Humean Libertarianism 9783110320701, 9783110320503

Table of contents :
CONTENTS
ACKNOWLEDGMENTS
Introduction
1 Determinism
1.1 Epistemic Determinism
1.2 Logical Determinism
1.3 Ontological Determinism
1.3.1 Determinism in Quantum Theory
1.3.1.1 Copenhagen-like Theories of Quantum Mechanics
1.3.1.2 Bohmian Hidden Variables Theories
2 Necessity and Laws of Nature
2.1 Necessitarianism
2.1.1 Armstrong, Tooley, and Dretske
2.1.2 Bird
2.2 Broadly Humean Accounts
2.2.1 Orthodox Humeanism
2.2.2 Best Systems
3 Libertarianism
3.1 Noncausalism
3.2 Causalism: Agent Causation
3.3 Causalism: Event Causation
4 Objections against Event-causal Libertarianism
4.1 Objections against Alternativism
4.1.1 The Consequence Argument and the Truth of Determinism
4.1.2 Frankfurt-style Cases
4.1.3 Alternative Possibilities and Modern Science
4.1.3.1 Jordan, Penrose, and Hameroff
4.1.3.2 Kane
4.1.3.3 Balaguer
4.2 Objections against Control and a Humean Solution
4.2.1 The Argument from Luck and Selected Responses
4.2.1.1 Kane
4.2.1.2 Mele
4.2.1.3 Balaguer
4.2.2 Libet’s Experiment
4.2.3 Control in Humean Libertarianism
5 Humean Libertarianism: Fortes, Foibles, and Future Follies
References

Citation preview

Marius Backmann Humean Libertarianism Outline of a Revisionist Account of the Joint Problem of Free Will, Determinism and Laws of Nature

Marius Backmann

Humean Libertarianism Outline of a Revisionist Account of the Joint Problem of Free Will, Determinism and Laws of Nature

Bibliographic information published by Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliographie; detailed bibliographic data is available in the Internet at http://dnb.ddb.de

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CONTENTS Introduction 1 Determinism 1.1 Epistemic Determinism 1.2 Logical Determinism 1.3 Ontological Determinism 1.3.1 Determinism in Quantum Theory 1.3.1.1 Copenhagen-like Theories of Quantum Mechanics 1.3.1.2 Bohmian Hidden Variables Theories

1 11 12 17 24 37 40 47

2 Necessity and Laws of Nature 2.1 Necessitarianism 2.1.1 Armstrong, Tooley, and Dretske 2.1.2 Bird 2.2 Broadly Humean Accounts 2.2.1 Orthodox Humeanism 2.2.2 Best Systems

53 60 60 72 89 98 101

3 Libertarianism 3.1 Noncausalism 3.2 Causalism: Agent Causation 3.3 Causalism: Event Causation

119 122 127 143

4 Objections against Event-causal Libertarianism 4.1 Objections against Alternativism 4.1.1 The Consequence Argument and the Truth of Determinism 4.1.2 Frankfurt-style Cases 4.1.3 Alternative Possibilities and Modern Science 4.1.3.1 Jordan, Penrose, and Hameroff 4.1.3.2 Kane 4.1.3.3 Balaguer

147 148 148 166 174 175 182 186

4.2 Objections against Control and a Humean Solution 4.2.1 The Argument from Luck and Selected Responses 4.2.1.1 Kane 4.2.1.2 Mele 4.2.1.3 Balaguer 4.2.2 Libet’s Experiment 4.2.3 Control in Humean Libertarianism

189 190 193 199 207 210 213

5 Humean Libertarianism: Fortes, Foibles, and Future Follies

229

References

235

ACKNOWLEDGMENTS

I would like to thank numerous philosophers in Münster, Cologne, Munich, and Bielefeld, especially Andreas Hüttemann, Thomas Grundmann, Alexander Reutlinger, Eva-Maria Jung, and Johannes Korbmacher for their helpful criticism, as well as Anna Blundell for her thorough proofreading. I would also like to thank Rebecca for her immense patience and my parents for their unconditional support.

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INTRODUCTION In the entire history of the free will debate, one fact always seemed certain: libertarianism, by its very definition as an incompatibilist position, cannot be reconciled with determinism.1 As I would like to show in this essay, it is this very cornerstone of the debate that has to undergo revision. At the end of this essay, I would like to have demonstrated that a certain account of libertarianism can be reconciled with a certain account of determinism, given that determinism is understood in a Humean fashion. This volume will consist of two main parts. In the first two chapters, we will discuss determinism and laws of nature regardless of their application in the free will debate. In the following two chapters, we will discuss the most prominent libertarian theories and their main problems. Firstly, I will explore the notion of determinism. It is a great defect of large portions of the free will debate that determinism is not properly analysed in this respect. We will see in chapter 1 that it is not only possible to make the usual distinctions between epistemic, logical, and ontological determinism, but that we can also distinguish at least two notions of ontological determinism2 which vary in strength depending on the theories of laws of nature that stand behind them. If we distinguish between two types of theories of laws of nature, necessitarian theories which propose modal forces in nature, and Humean theories which do not propose any modal forces, we yield two main types of ontological determinism: Humean determinism and necessitarian determinism. It is the very aim of this volume to show that a theory of free will that comes close to the traditional libertarian theories regarding the power to do otherwise and control is compatible with Humean determinism, but not with necessitarian determinism. So before we define a notion of free will that is compatible with Humean determinism, we have to make Humean determinism plausible. For this, we will in chapter 2 discuss the most popular theories of laws of 1 2

We will discuss the few exceptions to this rule in chapter 4.1. Throughout this essay, “determinism” will denote the theory of determinism.

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nature, which are David Armstrong’s, Michael Tooley’s and Fred Dretske’s necessitarian view,3 Alexander Bird’s dispositionalist account, the orthodox regularity theory,4 the best system view, most prominently put forth by John Stuart Mill, Frank Ramsey and David Lewis,5 and lastly a very recent amendment to the best system view, the so-called better best system view.6 At the end of the chapter, I will hopefully have shown that a Humean view is tenable. To show that a Humean view of laws and determinism is compatible with libertarianism, we have to discuss the various types of libertarian theories. We can distinguish three main types: noncausalist theories, agentcausal theories and event-causal views. These positions differ mainly in their view on what is taken to be the causes of free actions: events, agents taken as substances, or even nothing at all. We will return to these views in just a few lines below. In chapter 3, I will discuss and reject noncausalism and agent-causal theories, which leaves us with event-causalism. In chapter 4, I will explore the main arguments against the event-causal views of Robert Kane, Alfred Mele, who is actually agnostic about the truth of incompatibilism or compatibilism, but proposes two different libertarian views nonetheless, and Mark Balaguer.7 The problems that I will discuss are the consequence argument, the argument based on Frankfurt-style cases, arguments concerning the empirical evidence regarding the claims that event-causalists make about the workings of human brains, the argument from luck, and an argument based on the work of Benjamin Libet. I will try to show that these problems can be answered in a Humean fashion or can be settled independently. After having answered these problems in a Humean way, the outlines of a Humean libertarianism will hopefully begin to emerge. It has to be noted here that this essay is no attempt at a comprehensive discussion of all prominent theories of free will and a thorough defence of the one I propose. Instead, I will outline the above-mentioned libertarian theories and demonstrate how their problems can be solved in a 3 4 5 6 7

See e.g. Armstrong 1983 and 1998, Dretske 1977 and Tooley 1977. See e.g. Swartz 1995 and 2003. For a brief introduction, see Earman 1986, pp. 87-90. See Cohen & Callender 2009 and Schrenk 2008. See e.g. Kane 1996 and 2007, Mele 2006 and Balaguer 2010.

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Humean way. That in itself is not yet a thorough defence of Humean libertarianism and a refutation of all the other positions available. Likewise, I will concentrate on freedom, which, as we will see below, I take as a function of the power to do otherwise and agential control. The adjacent problems of moral responsibility and ethics will be left undealt with. Let us try to give an outline of the various libertarian theories. The range of possible types of positions in the traditional free will debate can be partitioned into a range of umbrella-positions which cover the actual theories. These main types of views on free will are a consequence of how one answers three central questions: Is freedom of will compatible with determinism? Is determinism true? And: do we have free will? If you answer the first with “yes”, you are a compatibilist. If you answer it with “no”, you are an incomaptibilist. Even in compatibilism, it is still relevant whether determinism is true or not, as some compatibilist positions require that determinism is true in order for humans to have free will.8 For all other compatibilist positions it is not relevant whether determinism is true or not, and the question whether we have free will has to be settled independently. If your answer to the original question about the compatibility of free will and determinism was “no”, then you are an incompatibilist. If you take determinism to be true, free will cannot be and you are a hard determinist. But if determinism is not true, it is still open whether we have free will or not. Incompatibilists that take determinism to be false and humans to be free are traditionally called libertarians.9 Lastly, there is the incompatibilist position that determinism is possibly false and yet we are still not free,10 which, according to John Martin Fischer, together with compatibilist theories that state that we have no free will is taken by a majority of philosophers.11 This partition into categories of possible positions is the traditional picture.

8 See e.g. Dennett 1984, p. 133. 9 See Fischer 2007, p. 3. 10 This position is e.g. taken by Derk Pereboom, who calls it “hard incompatibilism”. See Pereboom 2001, 2002 and 2007. 11 See Fischer 2007, p. 3.

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Yet there is still another way to arrive at a feasible definition of libertarianism, which does not require it to be grounded in the matrix of possible answers to the questions given above. It is possible to just consider what libertarians take free actions to be and define freedom accordingly. Traditionally, these definitional features of libertarianism are taken to be incompatible with determinism, hence the traditional belief that libertarianism is an incompatibilist theory. At the end of this essay, I hope to have shown that whether this is the case depends on your definition of determinism and laws of nature. The most important features that define libertarian theories apart from its incompatibility with determinism are the principle of alternative possibilities, the power to do otherwise, and control. 12 It is the definition of these criteria that can also be used to set the possible space for theories of free will. The principle of alternativism is the view that for an action to be free, somewhere in the process of deliberation and decision, there must exist at least two possible ways to act. Defenders of this principle claim that for an action to be free, at some point it must be the case that there are at least two real alternatives, and in addition to this that the agent has the power to cause either of these alternatives. This is commonly called the power to do otherwise. It is the principle of the power to do otherwise that prima facie clashes with determinism and traditionally marks libertarianism out as an incompatibilist theory. Taken thus, alternativism implies that the future is, as put by Jorge Luis Borge and frequently cited by Robert Kane, “a garden of forking paths”.13 Let us try to define the term “alternative” more technically. For this, let us consider Niko Strobach’s definition of alternative. In his defence of a neo-Kantian libertarianism, Peter Rohs discusses the notion of alternative and its implications for free will so thoroughly that we can lift the conceptual framework from his paper. Rohs utilises the definition of alternative given by Strobach:

12 Authors who stress the importance of these three criteria include e.G. Robert Kane (Kane 20022, Ansgar Beckermann (Beckermann 2004, p. 1), and Henrik Walter (Walter 1999, P. 24). 13 See Kane 2005, p. 7.

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Alternative = A possible development of the world h and another possible development of the world h' are real alternatives at time t, iff h and h' have an identical content until t.14 Rohs adds that in order to be alternatives, possible courses of the world need not only to be identical until t, but of course to be different afterwards. Adding this aspect to the original definition, we yield a clarified definition of alternative: Alternative = A possible development of the world h and another possible development of the world h' are real alternatives at time t, iff h and h' have an identical content until t and a mutually different content after t. This modified definition of „alternative“ will be used throughout this volume. The notion that the existence of alternative possibilities is a prerequisite for freedom is usually called the “principle of alternative possibilities”, or PAP for short. This principle has to be distinguished from the principle of the power to do otherwise (PPDO), which adds to PAP the condition that the agent has the power to cause either alternative: Power to do otherwise = At the moment of decision t there exist at least two real alternatives h and h' and the agent has the power to cause either of them. At this stage it should have become obvious where the work lies that has yet to be done. Firstly it seems obvious that the definition of “alternative” given above seems to collide with determinism. Determinism in an ontological sense can be taken to be the thesis that exactly these alternatives do not exist. In fact, Strobach defines determinism as the thesis that possible courses of the world with identical content until t necessarily have an identical content afterwards, which is in accord with John Earman’s definition of determinism as presented in his groundbreaking 1986 book.15

14 Strobach 2007, p. 56 and Rohs 2009, p. 134, my translation. In order to enhance readability, short, partly formalised definitions, formulae, and arguments that are citations will not be set in a smaller typeface which would have been the standard for citations. 15 See Strobach 2007, p. 56 and Earman 1986, p. 13.

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Libertarian freedom does not only depend on PAP and PPDO as developed above. It also depends on of the principle of control. Let us now try to develop a tentative analysis of latter term. Control has also been a main target for opponents of libertarianism and compatibilism in recent times. Roughly speaking, the principle of control requires that the agent is in some sense accountable for her actions, that she is the source of her own actions. The agent's actions have to happen due to her own beliefs and desires, for which according to some contestants she has to be ultimately responsible, which means that the agent's actions must not be determined by events beyond her control or even physically external to her. In the chapters 3.1-3.3, we will discuss the most prominent philosophical positions which concern the question whether and how the agent causes her actions. One of the main arguments against control is the argument from luck,16 which we will discuss in chapter 4.2.1. The debate about control concerns the proper relation of reasons to act and the actions, as well as the proper causal history of the reasons to act. In this volume, I will use Galen Strawson’s definition of reasons. Strawson holds that reasons are mental states, which does not entail that they are not reducible to physical states. These mental states are beliefs and desires.17 At first, we can, following e.g. Alfred Mele,18 distinguish two main notions of control: proximal control and ultimate control. According to Mele, to have proximal control over an action means that an agent's actions are directly caused by her own desires and beliefs. The falsity of determinism is not required for proximal control.19 Proximal control can, stripped of the specifics of Mele’s own account, be tentatively defined as follows: Proximal Control = An agent has proximal control over her actions iff her actions are caused by her beliefs and desires. That the agent's actions are caused by her beliefs and desires seems almost trivial, which, in fact, it is not, as we will see in chapters 3.1-3.3 and chapter 4.2. To some, this type of control does not go far enough. 16 17 18 19

See e.g. van Inwagen 1983, p. 16. See Strawson 1986, pp. 33-34. See Mele 1995, pp. 211-212. See e.g. Mele 2006, p. 7.

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Proximal control allows that the proximate causes of free actions, our beliefs and desires, are in turn caused by factors beyond the agent’s reach. It might be argued that in order to really control an action, an agent must also control the action’s causes. This type of control is called “ultimate control”. A tentative definition could go as follows: Ultimate Control = An agent has ultimate control over her actions iff they are caused by her beliefs and desires and these beliefs and desires were chosen by the agent. What does it mean for an agent to be the source of her own beliefs and desires? Kane, who discusses this aspect in terms of responsibility, insists that to be ultimately responsible for an action the agent must be responsible for the action’s proximate causes, which in Kane’s view means that the proximate causes of actions have to be caused by the agent’s character, which she formed in decisions which were undetermined by external factors.20 The notion of ultimate control also plays an important role for the famous consequence argument for incompatibilism, which argues that we have no control over our actions if they are the consequences of events in the past and the laws of nature, neither of which we control. In this volume, the consequence argument will, taken in conjunction with the hypothesis that determinism is true, be treated as an argument against the power to do otherwise, and not as an argument against control. The reason for this will become apparent in chapter 4.1.1. Above proximal and ultimate control, there are yet two more notions of control left to consider. Both definitions of control stated that control involved the causal efficacy of reasons to act. This is in accord with eventcausalist theories of action which claim that actions are per definitionem caused by reasons to act. The fact that an agent has a belief or a desire at a certain instant is an event. We will see in chapter 3.2, there are philosophers who do not take actions to be caused by events, but rather by the agent herself, who proponents of these theories view as a substance. The classdefining archetype for theories of this kind is Roderick Chisholm's view. Chisholm holds that there are two entirely different types of causation: 20 See Kane 2007, pp. 14 and 16-22. I will return to Kane’s view later in this volume.

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event causation, which is the type of causation that relates physical events, and agent causation, which relates agents and their physical effects.21 We will turn to agent causation in greater detail in chapter 3.2. For our purposes here it is sufficient to note that there is not only a different type of causation, but also a different kind of control involved. Let us try to give a tentative definition of this kind of agent-control: Agent-Control = An action is agent-controlled iff the cause of that action is the agent herself who is a substance and is not causally responsive to external physical causes. There is one last notion of control left to consider. As we will see in chapter 3.1, there are libertarians such as Carl Ginet and Hugh McCann22 who hold that free actions are not caused by reason-states, or that actions even lack a cause at all. This is the so-called noncausalist view. Noncausalism again requires its own notion of control which does not presuppose the causal efficacy of reason-states. Yet still for an agent to be in control of her actions and for these actions to be rationally explicable, they have to be done for a reason which in some way or another has to accompany the actions.23 We will turn to the subtleties and problems of the noncausalist view below, so let us tentatively define its notion of control as follows: Noncausal control = An action is controlled by the agent iff it is accompanied by a reason to act which is causally inefficacious in relation to the action. Thus at the end we have four possible definitions of control that are applicable to the most common types of libertarian theories. We will see all four definitions of control at work in the discussion of libertarian theories and the attacks against them below. One important terminological remark is in order. Often, the problems concerning the relation of reasons to actions and concerning the source of these reason-states are not discussed in terms of control, but in terms of origination, sourcehood or responsibility. Many discussions in the debate 21 22 23

See e.g.Chisholm 1982, p. 25. See e.g. Ginet 1990, 1997 and 2002, and McCann 1998. See e.g. McCann 1998, p. 180.

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about free will concern the notion of responsibility as a relation between reasons and actions, and the amount of control an agent has over his reasons to act. In fact, many arguments that are designed to show that some particular theory of free will does not procure a reasonable notion of moral responsibility try to demonstrate that an agent is not responsible for her action because she lacked proper control over them.24 In order to avoid the pitfalls of ethics, questions concerning responsibility or any moral considerations will be left undealt with in this volume. Although responsibility, sourcehood, origination and control are not synonymous (maybe sourcehood and origination are, but that is beside the point), what they have in common is that they are discussed in terms of reason-states and their relations to actions. To bundle all the arguments in the debate about free will that concern the relation between reason-states and actions, I will discuss them in terms of control. Whenever the respective authors’ terminology differs, I will allude to the difference. With these terminological considerations in mind, let us start to investigate whether some notion of free will which satisfies PAP, PPDO and control in a way that is close to how traditional libertarians understand them can be reconciled with Humeanism regarding laws of nature and determinism. To cite Peter Kosso: “enough with the slogans, it's time for details”.25

24 See e.g. Pereboom 2001, p. 116 for his discussion of his famous four-case argument, which we will discuss in chapter 4.2.3. 25 Kosso 1992, p. 114.

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1 DETERMINISM Although the notion of determinism has a great impact on the free will debate, it is not always as carefully presented as necessary. I will not attempt at an historic overview of the debate, but let us try to differentiate the main types of deterministic theories. Notions of determinism can be divided into three categories: epistemic determinism, logical determinism, and ontological determinism. As we will see, ontological determinism usually comes as a modal statement about the impossibility or necessity of the occurrence of events. Most of the attacks against libertarian free will are based on ontological determinism, but to show why only ontological determinism is relevant for our purposes, all three versions will be outlined below. Ontological determinism will be presented in greater detail than the other two versions because it is, as we will see, the variant of determinism that is relevant for our discussions of the principle of alternative possibilities and the power to do otherwise. Since ontological determinism is classically regarded as being incompatible with the power to do otherwise and the principle of alternative possibilities, we will also have to see whether ontological determinism is true. For this, we will take a brief look at quantum theory. This will also enable us to evaluate certain libertarian theories of free will which rely on an indeterministic interpretation of quantum theory in the chapters 3 and 4. In our discussion of ontological determinism, one important distinction will be made between theories of determinism that rely on necessitarian theories of laws of nature, and Humean varieties of determinism that do not propose modal forces in nature. One further distinction can be made between global and local determinism. Global determinism is the statement that the world in total is deterministic (however that may be defined) for all times past, present or future. Local determinism is the thesis that determinism does only apply to a certain restricted area, to certain types of processes or at certain times. In the rough outline of theories of determinism below, global or local determinism will not be differentiated. Whenever it makes any crucial difference they will be treated separately, but where it does not make any difference, they will not.

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1.1 EPISTEMIC DETERMINISM Epistemic determinism is the thesis that the world in total or any further to be specified isolated set of events is determined, if and only if it is on principle possible to forecast the state of that system at all times for all times. There has been some confusion in the debate about how to name epistemic determinism. Sometimes, it is referred to as "Laplacian Determinism",26 a label that is frequently attributed to ontologic determinism as well.27 Pierre-Simon Marquis de Laplace formulated the first influential modern theory of determinism that has become so commonplace that until this day it is often taken as the received view of determinism. In his famous thought experiment, Laplace asked us to imagine a vastly powerful mind, the Laplacian demon, who is informed about the exact state of the world at a certain time t and who knows all the laws of nature as well. Laplace states that given the truth of determinism, that demon would then be able to deductively infer any state of the world after t.28 The demon would be able to predict even the tiniest of details in the behaviour of any object in the world, be it even an elementary particle on a moon of some distant planet. It is this famous thought experiment by Laplace that gave rise to the current confusion about which version of determinism it illustrates, as it has been read either as illustrating the thesis of epistemic determinism, or as an addition to thesis of ontological determinism to the effect that, given ontological determinism were true, any future state of the world would be on principle predictable. Most texts that concern determinism at some point cite Laplace's famous passage containing the thought experiment, and this text will be no exception. Laplace writes:

26 John Earman for example uses “Laplacian determinism” as a label for epistemic determinism, because he interprets Laplace’s definition to be epistemic (see Earman 1986, pp. 6-8). 27 See e.g. Keil 2007, pp. 18-19. 28 See Laplace 1951, p. 282.

13 We ought to regard the present state of the universe as the effect of its antecedent state and as the cause of the state to follow. An intelligence knowing all the forces acting in nature at a given instant, as well as the momentary positions of all things in the universe, would be able to comprehend in one single formula the motions of the largest bodies as well as the lightest atoms in the world, provided that its intellect were sufficiently powerful to subject all data to analysis; to it nothing would be uncertain, the future as well as the past would be present to its eyes.29

There you can see the source of the confusion. Laplace ties the theses of ontological determinism and predictability tightly together without explicitly defining determinism in one sense or the other. Let us take a closer look at Laplace's definition. His criterion that the present state of the universe taken as a single unity ought to be regarded as the cause of the state of the universe that is to follow and as the effect of the state of the universe before is quite curious. Earman criticises that firstly, it is unclear which kind of causation can make sense of complete states of the universe instead of single events as causes and effects. Secondly, and even more importantly, it is not at all clear whether this definition of determinism can satisfy the intuition that determinism is a thesis that informs us about the necessity of one future course of events and the impossibility of any other courses of events different from the one that actually does happen. That one state of the universe causes another does not imply that this causation, even if we could find a theory of causation that can make sense of it, is deterministic as opposed to e.g. probabilistic.30 And then there is the reference to predictability. Laplace asserts us that if the world were deterministic, a mind as vast as his demon's would be able to predict any future event given he has access to complete knowledge of laws of nature and the exact present (or past) state of the universe. This statement has been contested lately, ever since chaos theory has given rise to the question whether really all ontologically determined processes were predictable on principle. Geert Keil for example, taken pars pro toto as a typical participant of the free will debate, holds that chaos theory suggests that some processes such as the forming of weather phenomena are so complex that their outcome is unpredictable. Two aspects of chaotic 29 30

Laplace 1951, pp. 281-282. See Earman 1986, pp. 5-6.

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systems seem to support such a claim. Firstly, there is the fact that chaos theory suggests that there exist complex physical systems in which tiny changes in the initial conditions could have vast changes in macroscopic effects. Tinker a bit with the initial conditions, and the outcome of the process could be entirely different. Secondly, in chaos theory the causal mechanism producing the macroscopic effects is so complex that it is impossible to reconstruct it formally as needed for a precise forecast. Nevertheless, a chaotic system could be perfectly ontologically determined. Hence, as Keil argues, determinism does not entail predictability and consequently should not be defined in terms of it.31 But chaos theory does not at all prove that there are physical systems which are ontologically determined, yet unpredictable on principle. We have to differentiate between deterministic chaos and indeterministic chaos. The crucial difference is that deterministic chaos merely mimics indeterminism, whereas in indeterministic chaos indeterministic laws apply.32 The fact that deterministic chaotic systems are not predictable stems from the extreme sensitivity to very small changes of the initial conditions and from the sheer complexity of that system.33 But that entails that the unpredictability is due to our human limitations to collect and process the crucial data, even when aided by means of computer science. That does not entail that nobody, not even with a more powerful mind than ours, better computers, and better mathematical models available to him than we have today, and enough time on his hand to actually collect the crucial data, could predict a deterministic chaotic system. So deterministic chaotic systems need not be unpredictable on principle, it is just impossible for humans of the year 2011 to do so, but there is no reason to presume that a mind of the Laplacian sort could not be up to the task, unless determinism fails to be true. In short, deterministic chaotic systems do not on principle forbid prediction, but we are just too limited to process the required information.

31 32 33

See Keil 2007, p. 17. See Eckhardt 2003, p. 50-51. See Suppes 1993, p. 249-250.

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So to wrap up, the confusion as to which version of determinism Laplace wanted to put forward can partly be solved when we look at his infamous statement that the entire present state of the universe is to be regarded as the effect of an earlier entire state of the universe and the cause of the state to follow. Laplace does not explicitly state that determinism is to be defined this way. However, it seems as though the alleged predictability that he so famously illustrated by his demon is merely a consequence of the ontological claim that any future state of the universe is a causal consequence of an earlier state. Nevertheless, this ontological aspect of Laplace’s characterisation of determinism raises the above-mentioned questions whether total states of the universe can be causes and whether the causation has to be deterministic. To cause an event does not necessarily mean to determine an event. We will turn to these problems in the paragraph which concerns ontological determinism. Now that we have established that Laplace was not necessarily a proponent of epistemic determinism, let us look at Karl Raimund Popper’s definition of epistemic determinism. Popper, in contrast to Laplace, dropped the notion of cause and effect altogether in his definition of ‘scientific’ determinism. Popper tried to define a theory of determinism that is free of any deep metaphysics and is as close to scientific practice as possible, if determinism was to be of any use as a concept at all. Popper defined scientific determinism (if only to refute it) as the thesis that any state of a closed physical system can on principle be predicted: The doctrine of ‘scientific’ determinism is the doctrine that the state of any closed physical system at any given future instant of time can be predicted, even from within the system, with any specified degree of precision, by deducing the prediction from theories, in conjunction with initial conditions whose required degree of precision can always be calculated (in accordance with the principle of accountability) if the prediction task is given.34

A couple of details have to be noted here in order to understand Popper's definition of determinism properly. Firstly, there is the principle of accountability. This principle states that the required degree of precision 34

Popper 1982, p. 36.

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for the prediction can be known before the act of prediction so that any failure to predict accurately cannot be excused by a lack of knowledge of the required precision of the initial data.35 Secondly, it has to be noted that Popper's demon is no superhuman demon at all, but only a super-scientist.36 Thus, Popper gets rid of the mentioning of metaphysical concepts like a godlike mind. But even more importantly, Popper's demon is just a physical spectator within a closed physical system. That is a very curious twist to the state of the problem, but inevitable, given Popper wanted his demon to be a finite mind of a quite mundane kind like a super-scientist or a super computer for example. Popper then criticises his own definition of scientific determinism by stating that a spectator who is part of a given closed physical system cannot be able to predict a complete future state of the system, including certain events of his own. To describe a closed physical system from within the system with whatever precision the spectator wants to, like a Popperian super-scientist should be able to, is especially problematic if we consider that observation is nothing but physical interaction and hence every observation distorts the physical system that is to be observed. Normally, this is no problem, as the precision required in everyday physics is nowhere near great enough to distort the observed phenomena to a relevant degree, although quantum events are an exception here. But a Popperian super-scientist should be able to predict as precisely as he likes, and by that he would distort what he wants to observe. Since the super scientist should be able to predict the entire state of the universe, he would distort what he wants to observe and predict when he calculates the effect of his interaction, and so forth ad infinitum. Ultimately, this is the reason why Popper rejects epistemic determinism.37 Epistemic determinism has the advantage of being largely void of any metaphysical assumptions, if you are inclined to call this an advantage. In contrast to ontological determinism, it does not include any notion of necessity, which would be in need of explication. But however plausible or implausible epistemic determinism might be, it is not incompatible with the libertarians’ claim that an agent has at least at some points in his life at 35 36 37

See Popper 1982, p. 36. See Popper 1982, p. 34. See Popper 1982, p. 36.

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least two genuine alternative possibilities how to act and can cause either of them. Predictability of one way how to act does not make any other alternative course of action impossible. The epistemic determinist might not have an ontological notion of possibility and necessity, but the libertarians have. To put it more clearly, that it is possible to predict a certain event does not entail that immediately before this event, there was no alternative in the sense discussed in the introduction. John Earman holds that the fact that a god-like demon can predict the future does entail that the world is deterministic, for the demon’s ability to predict may only indicate his precognitive ability rather than the fact that the world is deterministic. This of course does not hold for Popperian epistemic determinism, which does not require a godlike mind. But even in this view, the fact that the super-scientist is able to predict the future may be a consequence of the fact that the world is deterministic, but that does not define determinism. Earman holds that we should not […] confuse the implications of the doctrine with the doctrine itself.”38 Moreover, we have seen that determinism need not imply predictability. To put it in the words of, again, John Earman: “[…] determinism and prediction need not work in tandem; […].”39 So we do not have to consider further arguments for or against epistemic determinism, as it is of no importance here anyway. Let us now turn to a notion of determinism that might indeed be incompatible with alternative possibilities.

1.2 LOGICAL DETERMINISM Logical determinism is the consequence of a logical problem that results in the claim that because propositions about future events are true or false even before the events occur, the events that the true propositions refer to must happen necessarily. Logical determinism has often been discussed in connection with the theological problem that given God's omniscience, he must know, or be able to forecast, all events past, present, and future. And if God knows all future events and knows which propositions about future events are true and which are false, then the future events are necessarily going to happen as God predicts.40 Note, however, that 38 39 40

Earman 1986, p. 8. Earman 1986, p 9. For a thorough overview over the problem of divine foreknowledge and free will,

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although the problem of logical determinism and the problem of divine foreknowledge are intertwined, the existence of an omniscient mind is not necessary to spell out the problem of logical determinism itself, as the latter unfolds even without the presence of an omniscient mind. At the end of this section, we will take a brief look at a modern Ockhamist solution to the problem of logical determinism, mainly because of the interesting concept of necessity per accidens. An extraordinarily thorough discussion of the Ockhamists' solution can be found in Alfred Freddoso's 1983 article titled “Accidental Necessity and Logical Determinism”.41 The theory of logical determinism plays no central role in the current debate on free will, as most commentators seem to agree that something obviously must be wrong with it. I will leave most of the technical problems aside and concentrate on what I take to be the central criticism of logical determinism, i.e. that the truth or falsity of statements cannot necessitate (in an interesting sense of “necessitate”) future events. A brief discussion of Swartz's, Keil’s and Freddoso's solutions hopefully illustrates that point. So let us take a closer look at the problem. A very prominent example to illustrate logical determinism is Aristotle's sea battle.42 A slightly modernised version of this argument goes as follows: imagine two admirals preparing for a sea battle that is going to take place tomorrow. The three propositions “admiral A will win the oncoming sea battle”, “admiral B will win the oncoming sea battle” and “either admiral A or admiral B will win the upcoming sea battle” are all true or false before the sea battle. Which of the admirals will win we probably cannot say due to epistemic restrictions, but we know that, given the battle will have a definite outcome, at least two of these propositions already are true before the event: the disjunction and one of the other two propositions. Let us say that admiral A will win the sea battle. Then the proposition “admiral A will win the sea battle” is true. But if a proposition is true, it cannot be false. Hence, it is necessarily true. If a proposition is necessarily true, the opposite is impossible. So, since the proposition “admiral A will win the sea battle” is true even before the battle, it is impossible that the see Zagzebski 1991 and 2002. For a classical formulation and discussion of the argument from divine foreknowledge, see Pike 1965. 41 Below, I will cite a 2005 reprint of the original 1983 paper of the same name. 42 See Aristoteles De Interpretatione, chapter IX

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proposition “admiral B will win the sea battle” is true. Hence, so the argument goes, admiral B cannot possibly win. But if it is true today that admiral A will win the battle tomorrow, why should admiral B bother to fight at all?43 The argument rests on two important logical principles: the principle of the excluded middle and the principle of noncontradiction. Now expand Aristotle's argument to the total state of our universe at all future times, and for every event that is going to happen, there is a proposition that describes this event that is true before the event. Obviously, the contradiction of any of these true propositions is false. The logical determinists now say that because there is a set of propositions that correctly describes each and every future event such as the sea battle in Aristotle's argument, each and every event necessarily has to happen as described in the already true proposition.44 This result is baffling. But the problem is that although it seems perfectly clear that the truth or falsehood of a sentence or a proposition cannot necessitate future events, it is actually not quite so simple to put the finger on what is actually wrong with the argument. Norman Swartz, who discusses logical determinism briefly, sketches three possible options to reply to the argument, of which we will only consider the third, on which his own response to the problem is based: Swartz suggests that the truth or falsity of sentences or propositions does not necessitate events. The proposition “Admiral A wins the sea battle at time t”, is made true by the event of A's victory at time t. This does neither entail that the proposition did not have a truth value prior to t nor that his victory at time t backwardly caused the sentence to be true at any time prior to t. To accept backward causation would be even less appealing then to reject the principle of the excluded middle solely on the grounds of the problem of logical determinism or to accept that the relevant proposition did not have a truth value before t, which was Aristotle’s classical response to the argument.45 As Swartz points out, the relation between the 43 The last question signifies the importance of this argument to the problem of logical fatalism, which will not be discussed here. 44 See e.g. Swartz 2004 (no page numbering), or Freddoso 2005, p. 308 for a more carefully presented version of the argument. 45 See Aristotle, De Interpretatione, chapter IX, and Freddoso 2005, p. 309, for a

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truth value of the proposition and the events that makes the proposition true is a semantical relation, not a causal one. The truth value of a proposition regarding a future event that makes this proposition true or false may be unknown, or maybe even on principle unknowable to us, but that neither means that the proposition has no truth value prior to the event nor that the event in question makes the proposition true when it occurs and by this backwardly causes the sentence to be true prior to the event's occurrence.46 Swartz's refutation of logical determinism based on the third option rests upon the above-mentioned concern about a mixup between two types of necessity. Swartz states that causally necessitating an event is nothing a proposition could possibly do. Even if there is some sense in which it can be said that the truth of a proposition necessitates anything, it seems pretty obvious that propositions cannot causally necessitate an event. Any necessity within the realm of propositions cannot, if Swartz is to be believed, be the same kind of necessity as in the physical realm, if there even is any, which the Humean Swartz disallows.47 According to Swartz, only events can cause events, propositions cannot. If there is any sense in which an event can necessarily bring about another event is a further aspect to be discussed below. In fact, believers in Humean supervenience reject the idea that there is any necessity in the physical world at all.48 A very similar response is given by Geert Keil, who holds that the logical determinists’ talk of the inability to change the future is only a linguistic artefact. In a sense, Keil admits, we are not able to change the future: if we take our actual future to include everything what will happen, including our actions, then we cannot possibly change it. But that does not entail that we do not have the power to decide which of the possible futures come about. We may not be able to change the actual future, but we may very well be able to decide what future will be the actual future. And whether this is actually possible is not a question that is to be settled by logic, but by our debate about ontological determinism. The relevant sort modern account and refutation of Aristotle’s response. 46 See Swartz 2004, no page numbering. 47 See e.g. Swartz 1995, p. 85. 48 For a formulation of Humean supervenience that is neutral in respect to how to characterise the subvenient base, see e.g. Earman & Roberts 2005, p. 7.

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of necessity that is responsible for the question which events are determined to come about and which not is, according to Keil, metaphysical necessity, not logical necessity, which is the kind of necessity invoked by the arguments for logical determinism.49 Although Keil’s critique of the relevance of logical determinism is compelling, a remark is in order. Whether metaphysical necessity is the relevant sort of necessity for ontological determinism is very much disputed and is dependent on the theory of laws of nature behind it. We will turn to these questions later. Swartz’ and Keil’s objection that even if there is some sense in which the truth of a statement entails the impossibility of its contradiction, this modality cannot determine events, is what I take to be the central aspect of the problem of logical determinism: to mistake a semantic relation with necessitation. The unease attached to the circumstance that a sentence describing a future event such as “Marius will eat a cake later this day” has a truth value prior to my eating the cake that results in the assumption that the truth value of the sentence determines the event in the sense that it necessitates the event to happen. And this is obviously nonsense. A very different but promising line of response against logical determinism can be provided by application of Ockhamism to the present debate.50 For this, let us firstly discuss a more carefully formulated argument for logical determinism given by Alfred Freddoso in the context of his Ockhamist critique of logical determinism. Logical determinism of any form is in some way dependent on the notion of necessity per accidens. If e.g. it is contingently true at t that p is the case at t, then it is at every time after t necessary per accidens that it is true that p was the case at t.51 According to Freddoso, the argument for logical determinism rests on two principles: (B) If p entails q, and p is necessary per accidens at t, then no one has the power at or after t to bring it about that q is or will be false.

49 See Keil 2007, p. 24. 50 There are numerous other options available. For an overview, see Rice 2010 and Zagzebski 2002. 51 See Freddoso 2005, p. 304.

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(C) If p is true at t, then the proposition that p was the case is necessary per accidens at every moment after t, and the proposition that p was never the case is impossible per accidens at every moment after t.52 With these principles, Freddoso gives the following argument for logical determinism. Consider Katie, who washes her car at some definite moment in time T:53

(P1) The proposition that Katie will wash her car at T is true now, long before T. (assumption) (P2) So the proposition that it was the case that Katie will wash her car at T will be necessary per accidens at every future moment, including every moment that precedes or is identical with T. (from P1) and (C)) (P3) But the proposition that it was the case that Katie will wash her car at T entails the proposition that if T is present, then Katie is washing her car. (assumption) (P4) Therefore, no one (including Katie) will have the power at or before T to bring it about that it is or will be false that if T is present, then Katie is washing her car. That is, no one will have the power at or before T to bring it about that it is or will be true that Katie is not washing her car when T is present. (from (P2), (P3), and (B)54

The Ockhamists's response to that is, if you excuse the woefully brief roundup of the Ockhamist's stance, that the present bears a rather special ontological status that the past and the future do not. Alfred Freddoso and Marilyn McCord Adams count as two influential present day defenders of Ockhamism.55 The Ockhamists claim that there are soft facts about the past 52 Freddoso 2005, pp. 306-307. 53 In this case, I will depart from the usual notation in this essay and abide with Freddoso’s notation of capitalised Ts as determinate instances of time. 54 Freddoso 2005, p. 308. 55 See e.g. Freddoso 1983/2005, McCord Adams 1967, Alvin Plantinga 1986, and

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that depend upon the present. Freddoso argues that the entailment of (P2) by (P1) and (C) fails because of the falsity of the otherwise intuitively plausible principle (C). Freddoso argues that it is not the case that the fact that it is true before T that Katie will wash her car at T entails that it is necessary per accidens that it was the case that Katie will wash her car at T. Freddoso claims that (C) is too strong because the truth of the present tense proposition that Katie washes her car at T does not depend on the fact that the the future tense proposition that Katie will wash her car at T was true before T. Freddoso claims that the truth of the future tense proposition depends on what is purely present at T, and on nothing else. This is the primacy of the pure present that the Ockhamists propose. Consider the proposition that Katie will wash her car T is true before T. At T, if Katie has the power to do anything she likes, even not washing her car, she would have to have the power to make it the case that the future tense proposition that she will wash her car at T, which was true before T, had been false. That is, she has to have the power to change the past in a certain way. The Ockhamists claim that in a very restricted sense, she actually does. If the present can be described with present tense propositions whose truth does not depend upon the past and if the truth of past or future tense propositions depends upon the truth of present tense propositions, then there is a sense in which the truth of a past future tense proposition (i.e. a proposition in future tense issued in the past) before T depends upon the truth of the according present tense proposition at T. Obviously, this dependence is not causation, as this would indeed entail backwards causation, which has to be avoided at all costs, but a semantic relation instead. 56 The technical details of the debate about Ockhamism are frighteningly complex,57 and we will skip them here for the sake of brevity. Freddoso’s as well as Keil’s and Swartz's answer to the problem all point in the same direction: if we are talking about the fact that an event is determined, what Bruce Reichenbach 1988. For an overview of the Ockhamist solution in the context of divine foreknowledge, see Zagzebski 2002, pp. 53-55. Zagzebski concludes that Ockhamism has not been discussed much in the last decades, and that it will be interesting to see how it develops (See Zagzebski 2002, p, 55). 56 See Freddoso 2005, pp 308-310. 57 See Freddoso 2005, pp. 311-323 for some of the frighteningly complex details.

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we mean by that is that this event is necessary in a physical sense,58 and not that it is entailed by a proposition which is necessary per accidens. So to evaluate, logical determinism is a claim that intuitively strikes one as highly implausible but actually is rather hard to refute. The arguments by Swartz, Keil and Freddoso briefly recapitulated here hopefully show that logical determinism is no threat for libertarian free will and can and will be ignored in the further course of this book. So let us now finally turn to a version of determinism that actually is incompatible with libertarian free will.

1.3 ONTOLOGICAL DETERMINISM59 In contrast to the other versions of determinism briefly discussed above, ontological determinism does not rest upon predictability or logical entailment. Ontological determinism is the thesis that being determined or not is a feature of the world, not of our knowledge about it or of language. Possibly the most enlightening work on ontological determinism has been given by John Earman, whose landmark achievement “A Primer on Determinism”60 has gained textbook status. The discussion of ontological determinism in this book will be developed mostly along the lines of John Earman's analysis and will come in two stages. In the first stage we will concentrate on the conceptual problems of defining determinism, and in the second stage we will take a brief look at the question whether determinism is true or false. Remember that classical libertarianism requires the falsity of determinism. As we will see in chapter 1.3.1, it is very much possible that determinism could be true, which should serve as an additional incentive to investigate whether determinism of any sort is actually incom58 I would like to avoid the term “physically necessary” until we had the opportunity to define it properly. To repeat and to avoid confusion: whether the determination of set of events entails a strong kind of modality like nomological necessity is very much disputed. We will turn to this question in the next section and in chapter 2. 59 Henceforth in this book the use of the term “determinism” always refers to ontological determinism, unless any other form of determinism is explicitly mentioned. 60 Earman 1986.

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patible with libertarianism. In the first part of this chapter I will try to analyse Earman’s definition of determinism. As it turns out, Earman’s definition as it stands does not suffice to capture the strong modal intuitions about determinism that will be discussed below. For this, his definition needs to be augmented with a necessitarian view of laws of nature. But we will see that it is also possible to combine Earman’s definition of determinism with a Humean theory of laws of nature that denies the existence of modal forces in nature. Earman is, after all, a defender of a best system account of lawhood, which is a Humean theory in the sense that it does not propose any modal forces in nature.61 We will see in chapter 2 that there exist good arguments against necessitarian theories of laws of nature and that a broadly Humean view could be defended, which yields only the weaker sense of determinism hinted at above. As we will hopefully see in chapter 4, this weaker sense of determinism does not support the most prominent attacks against free will. John Earman holds that his definition of determinism is meant to capture a certain set of intuitions about determinism. In the following paragraphs we will see whether his own theories of determinism and laws of nature are actually up to this task. These intuitions are that if global determinism is true, then the unfolding of any event that happens past, present, or future, is fixed by the laws of nature and the initial conditions of the universe that obtained at the very beginning of time. So, if determinism is true, every event that has ever happened or indeed will happen is rendered inevitable by the initial state of the universe and the laws of nature. Thus, nothing and nobody would have the power to bring about a real change to this fixed course of the world, since every event that could change the fixed course of things would be determined as well and hence no change of this fixation would be possible. These are the intuitions that any traditional account of determinism seeks to capture. Before evaluating conceptual analyses of determinism, let us consider some definitions of determinism as given by philosophers working in that field. We will see that most of these definitions involve a notion of necessity or impossibility of events and an appeal to causality. Robert Kane for example tries to

61

See Earman 1986, pp. 87-90.

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identify the core notion that is behind all forms that determinism has taken throughout history. This core idea is that if determinism is true, then for any event there exist conditions that make that event necessary: But a core notion runs through all these forms of determinism, which explains why these doctrines appear to threaten free will. Any event is determined, according to this core notion, just in case there are conditions (such as the decrees of fate, the foreordaining acts of god, antecedent physical causes plus laws of nature) whose joint occurrence is (logically) sufficient for the occurrence of the event: it must be the case that if these determining conditions jointly obtain, the determined event occurs.62

A very similar definition can be found e.g. in Paul Edwards’ Encyclopedia of Philosophy. There philosophical determinism is defined as the thesis that for every occurring event, there exist conditions such that if they obtain, no other event could have happened.63 Ted Honderich on the other hand defines determinism along the lines of causality. He claims that for an event to be deterministic, it must have an ultimate explanation which consists in citing the causal factors that made the event necessary.64 His definition of a determinist theory of action, where he applies his take on determinism to human agents, consequently goes as follows: Let us understand determinism as the family of doctrines that human choices and actions are effects of certain causal sequences and chains – sequences such as to raise the further and separate question, as traditionally expressed, of whether the choices and actions are free.65

The list could go on for a long time, but to get the general idea this should suffice. There is one aspect that all of these definitions have in common. They all tie the notion of determinism to the inevitability or necessity 62

Kane 20022, p. 6, original italics.

63 64 65

See Edwards 1967, p. 359. See Honderich 2002, pp. 461 and 462. Honderich 2002, p. 464.

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of events. According to these definitions, if determinism is true, then all events are not simply the way they are, but they have to be the way they are, they are compelled to be as they are. When John Earman sets out to investigate the notion of determinism, he quotes a passage from William James which sets the tone for the more elaborate versions of determinism to follow: What does determinism profess? It professes that those parts of the universe already laid down absolutely appoint and decree what the other parts shall be. The future has no ambiguous possibilities hidden in its womb: the part we call the present is compatible with only one totality. Any other future complement than the one fixed from eternity is impossible. The whole is in each and every part, and welds it with the rest into an absolute unity, an iron block, in which there can be no equivocation or shadow of turning.66

The three definitions of determinism cited above clearly satisfy James' remarks, even Honderich's causal analysis. Earman dismisses popular causal analyses as definitions of determinism which come as the doctrine that every event has a cause as missing James' point because a cause might bring the effect about merely probabilistically as opposed to deterministically.67 Honderich's definition is useful nonetheless, as the missing element that serves to fix the future might enter the definition again by stressing and explicating the notion of “necessary cause”. John Earman sets out to investigate whether various popular versions of determinism are in accordance with James' vision. In the end he arrives at his own definition which he in an act of crass understatement calls a mere ‘transcription’ of James's passage.68 I, however, would like to demonstrate that it isn't, at least not if not augmented with a necessitarian theory of laws of nature. Earman tries to define the necessity of future events by sameness of possible worlds. His definition of determinism goes as follows:

66 67 68

James 1956, p. 150. See Earman 1986, p. 6 or e.g. Keil 2007, p. 27. See Earman 1986, p. 14.

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The world W ϵ  is Laplacian deterministic just in case for any W’ ϵ , if W and W’ agree at any time, then they agree at all times.69 Here  stands for the set of all physically possible worlds. Readers familiar with the debate have probably wondered why the notion of natural law has not been mentioned so far: physically possible worlds are all the worlds in which the same laws of nature apply as in the actual world. That means the only way these worlds can differ is in their initial conditions and the consequences of the laws and the initial conditions. If two physically possible worlds share the same initial conditions at the beginning of time they will be identical for all times – they will indeed be identical simpliciter. Take the state of our world as it is now, and let us suppose that the laws of nature cannot change, then there is exactly one possible future and all other alternative future courses of the world are impossible. This is clearly at odds with the libertarian principle of alternative possibilities. So to the traditional libertarian, determinism must be false, so that our will can possibly be free. Before we turn to the question whether global determinism is true or false, let us turn to Earman's idea that his definition should satisfy James' intuition. But does it? There is exactly one source of vagueness in Earman's definition and that is the notion of physical possibility. An event is physically possible iff it occurs in at least one possible world which shares the same laws as the actual world. But do not the different theories of laws of nature have an effect on how and even which future events shall be rendered impossible, or possible, or necessary? Take for instance a necessitarian theory of laws such as those proposed by David Armstrong, Fred Dretske and Michael Tooley.70 If we leave the diverging details aside, their theories share the same core idea. It is the idea that the regularity theory of laws of nature 69 Earman 1986, p. 13, original italics. Note that this is the strongest of three possible versions of determinism. The universal determinism given above can be distinguished from historical or futuristic determinism by altering the last subordinate clause in “… then they agree at all later times”, or …”then they agree at all earlier times”. Historical or futuristic determinism will be irrelevant to the remainder of this text. 70 See e.g. Armstrong 1983, Tooley 1977, and Dretske 1977, as well as chapter 2.1.1.

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cannot cope with a series of problems such as e.g. the distinction between accidental regularities and real laws of nature71 and that we therefore need a theory of laws of nature that can. The reason Armstrong and the other necessitarians think the regularity theory cannot cope with problems such as accidental regularities is that it lacks a notion of necessity to the effect that a law of nature makes its instances necessary, that it compels its instances.72 In Armstrong’s, Tooley’s and Dretske’s view, a law is a necessitation relation between universals, such that the instantiation of one universal necessarily brings about the instantiation of another universal.73 Immediately, the question arises what kind of necessity Armstrong is talking about. It cannot be logical necessity, as in his view, laws of nature are neither sentences nor propositions, but relations between universals. Armstrong requires from his laws of nature that it has to be possible that our world could have had a different set of laws or nature. So in his view, the laws of nature we have in our world do have a modal force so they can make their instances necessary, but they themselves could have been otherwise. Armstrong proposes a rather peculiar notion of natural or nomological necessity which compels nature to behave in a certain way.74 We will turn to Armstrong's definition of laws of nature and hence his notion of nomological necessity later in the text. What we must bear in mind for our purposes here is that laws of nature in the necessitarian view are equipped with a modal force that necessitates, or forces, its instances to be a certain way. So in this theory, once we have defined the notion of laws of nature and nomological necessity a little more thoroughly, we should have a fairly thorough understanding of why certain events are necessary and hence all other different incompatible alternatives impossible. Alexander Bird offers a different take on necessitarianism based on a dispositional analysis. In his view, the laws of nature are consequences of the dispositional character of

71 See e.g. Armstrong 1983, pp. 11-23. 72 See Armstrong's thorough discussion of the regularity theory and its problems all throughout Armstrong 1983. 73 See e.g. Armstrong 1983, p. 55. 74 See Armstrong 1983, p. 80.

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the fundamental properties. In this view, instances of laws of nature are metaphysically necessary.75 We will discuss Bird’s theory of laws of nature in chapter 2.1.2. But what happens when we propose a theory of laws of nature which does not propose natural or metaphysical necessity? Take the regularity theory for instance. The motivation to propose a regularity theory is actually to propose a theory of laws of nature that satisfies Humean supervenience. We could try to characterise Humean supervenience according to John Earman and John Roberts as follows: HS: What is, and what isn’t, a law of nature supervenes on the Humean base of facts.76 What exactly the Humean base of facts might be, is subject to debate. We will turn to this question in chapter 2.2, but it is safe to say here that modal facts such as the instantiation of necessitation relations between universals do not belong to the Humean base. That means that if Humean supervenience is true, there are no necessary connections between singular facts, and hence, there is no necessitation between instantiations of universals. Or to put it in the language of theories of supervenience: there is no difference in the laws without difference in properties of singular occurrent facts.77 Humean supervenience would rule out any Armstrongian theory of laws of nature in which there exists a relation of necessitation between two types of instances of properties of singular occurrent facts. The standard regularity accounts, however, do satisfy Humean supervenience.78 The classical regularity view of laws of nature is the theory that laws of nature 75 See e.g. Bird 2005, p. 355. 76 Earman & Roberts 2005, p. 7. 77 See Lewis 1986, p. ix-xvi. 78 I am not sure whether the term “supervenience” is really appropriate to express what Humean supervenience wants to express. Ultimately, it is the thesis that there is nothing but singular facts and the properties they instantiate. But supervenience does not necessarily entail any kind of ontological reduction. There are weak concepts of supervenience such as “de facto supervenience” for example (Macdonald 1995, pp. 141-143) that can be used to describe a constant covariation between two classes of properties but do not amount to a thesis that ontologically, there is nothing but the subvenient base.

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are propositions that describe regularities in the world. These propositions take the form of logically contingent omnitemporally and omnispacially true universally quantified propositions devoid of references to particular times and places as well as Goodmanised properties such as “grue”.79 So in these views, what is to be counted as a law of nature can, after its truth has been asserted, ultimately be decided on the grounds of features of the proposition. Obviously, even Humeans, who deny the existence of necessary connections between facts, still use the notion of physical possibility and physical necessity. Don’t be mislead by the Humean’s talk of doing away with necessity: physical necessity, understood as occurrence in every possible world that shares the same laws as the actual, and physical possibility, understood as occurrence in at least one possible world that shares the same laws, are concepts the Humeans use as well. These notions do not require the existence of a modal force in nature. We will return to clear up these conceptual obscurities in a short while. There has been some debate whether any regularity theory of laws of nature can correctly identify the set of physically possible worlds. George Molnar’s classic version of an argument by William Kneale80 we are about to look at in the next paragraph is designed to show that the regularity theory can make no sense of the notion of physical possibility. Thus, as physical possibility is such an important feature of our talk about the world, the regularity theory should be given up. As a rather interesting result of Molnar’s argument, it is the regularity theory of laws of nature that yields the smaller set of physically possible worlds, i.e., there are less worlds that are in accordance with the laws of nature than there are according to a necessitarian theory of natural laws. How is that possible? The aim of Molnar's and Kneale's Argument is to show that the regularity view of natural laws rules out too many possible worlds as physically impossible. Their argument goes as follows: consider the sentence “Somewhere, somewhen, there exists a river of Coca-Cola.” According to Molnar, let us consider this sentence as being false, for at no time in the history of the universe there exists a river of Coca-Cola. But Molnar also defends the 79 See Molnar 1974, p. 106 for a comprehensive set of properties that a proposition has to have if it is to be counted as a law of nature in the regularity theory. For an explication of the grue problem, see Goodman 1983, p. 74. 80 See Molnar 1974 and Kneale 1950.

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intuition that this sentence should be regarded as describing a physical possibility.81 In his view the regularity theory does not yield this result. If at no time in the course of the world there exists a river of Coca-Cola, then the proposition “At no time in the history of the universe there exists a river of Coca-Cola” is true and can be expressed in the way the regularity theory requires of its laws of nature. But if the proposition “At no time in the history of the universe there exists a river of Coca-Cola” is a law of nature, then it would be physically impossible that at any time there is a river of Coca-Cola. But according to George Molnar and other necessitarians it should very well be possible that at some point in the history of the universe there is a river of Coca-Cola, because there is nothing in nature that prohibits rivers of sweet liquids. To universalise the argument, in the regularity theory it is possible to construct a negative law of nature for every universally uninstantiated type of events, and hence each and every omnitemporally and omnispacially uninstantiated type of events would be impossible, even the very possible ones such as rivers of sugary beverages.82 Note, however, that this argument rests upon two pillars. It rests upon the assumption that there can be negative laws of the form “No F is a G” and the intuition that sentences such as “Somewhere, somewhen, there exists a river of Coca-Cola” express a real physical possibility. It is the intuition that there are unrealised but false physical possibilities.83 Let us not brood over arguments concerning theories of natural laws any further but return to our point at hand. We wanted to establish that different views of laws of nature yield different effects if we combine them with Earman's definition of determinism. Interestingly, or rather shockingly, the regularity theory turned out to be the more restrictive theory when it comes to the size of the set of physically possible worlds. The necessitarian account seems to be a more permissive theory, as it only prohibits instances of types of events that are directly incompatible with what a necessitarian law of nature deems necessary. And since necessitarian accounts of laws of nature make a distinction between accidental 81 82 83

See Molnar 1974, p. 108. See Molnar 1974, p. 106-108. See Molnar 1974, p. 108.

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regularities and “real” laws, the set of actual laws in our world is considerably smaller than within the regularity account and hence, there are less events that are actually prohibited by laws. The necessitarian accounts of laws of nature are explicitly designed to cope with the problem of accidental regularities. A regularity such as “At no time in the history of the universe there exists a river of Coca-Cola” would not count as a law of nature in such a necessitarian account, as it would not be deemed necessary that there never is a river of Coca-Cola. And hence, the incompatible event that there is a river of that soft drink does not occur, but would be physically possible nonetheless. This is an interesting result. Does this mean that the regularity theory of natural laws is far too restrictive to be compatible with libertarian free will? One of the components of libertarian free will is the acceptance of at least some version of the principle of alternative possibilities. But if any omnitemporally and omnispacially uninstantiated type of events is impossible, the set of real alternatives would shrink quite severely. Before we jump to conclusions and declare Humeanism as the more restrictive theory, there is yet another aspect to be considered that will turn out to be the more important one. Remember that the regularity theory is meant to serve as a theory of laws of nature that is compatible with Humean supervenience. And this means that proponents of the classical regularity theory usually deny that there is any sort of necessity in the world. Norman Swartz, who proposes an orthodox regularity theory, writes: To abandon necessitarianism means to elevate – and to live with – contingency: the world does not have to be the way it is; it just is .84

Here lies a problem for Earman’s definition of determinism: While both Humeans and necessitarians have a notion of physical necessity as occurrence in every world that shares the same laws, just how much oomph85 84 Swartz 1995, p. 85. 85 I borrow this wonderful expression from a paper by Markus Schrenk in which he discusses metaphysical necessity and dispositional essentialism. Apart from oomph,

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this physical necessity has depends on the theory of laws of nature that one proposes. Obviously, if the regularity theory is true and given that there are no probabilistic laws, then our world is deterministic in the sense that it is identical with every other world that shares the same regularities and the same initial distribution of facts. Likewise, within the framework of Humeanism, the physical necessity of an event translates into saying that it occurs in every world which shares the same regularities. So for the Humean, determinism is nothing over and above the thesis that our world is regular, which is not a modal thesis in the sense that the occurrent facts have to behave regularly. For the Humean, this is no problem, as this is simply everything that can be said about determinism. But compare this to necessitarian theories of laws of nature such as the Armtrong-Tooley-Dretske view or recent dispositionalist accounts such as Alexander Bird’s.86 In these accounts, physical necessity is initially not defined differently than in a Humean framework, i.e. an event is physically necessary iff it occurs in every world that has the same natural laws as ours. But still, as in necessitarianism natural laws are necessity-providing entities over and above the regularities, their physical necessity has more oomph than the physical necessity of the Humeans. In necessitarianism, the instances of the laws events are forced to be as they are by the laws of nature: the laws make the facts necessary. Combine this sense of necessity with the notion of physical necessity as occurrence in every possible world with the same laws as the actual and you yield a notion of physical necessity according to which a fact is physically necessary if it has to occur in every possible world. To distinguish these senses of necessity let’s call the first “physical necessity simpliciter”, the second “necessity with a vengeance”, and the third “physical necessity with a vengeance”. We could characterise them as follows: Physical necessity simpliciter: A fact is physically necessary simpliciter iff it occurs in every world that shares the same laws as the actual world.

Schrenk also introduces biff as an alternative, but for the sake of simplicity, I will stick to oomph (See Schrenk 2010, p. 727). 86 See Bird 2005 and 2007.

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Necessity with a vengeance: A fact is necessary with a vengeance iff it is compelled by a law of nature. Physical necessity with a vengeance: A fact is physically necessary with a vengeance iff it is compelled by the natural laws to appear in every possible world that shares the same laws as the actual world. This distinction, unusual as it may sound, reflects George Molnar’s worry that physical necessity (and possibility) as the Humeans understand it is but a sad excuse for real physical necessity (and possibility) as the necessitarians understand it.87 Obviously, not every fact that is compelled by a law of nature has to occur in every physically possible world, since the physically possible worlds can differ in their initial conditions. Thus not every fact which is necessary with a vengeance has to be physically necessary with a vengeance. If this distinction between the types of necessity above is applied to Earman’s definition of determinism, this implies that while in a Humean view determinism amounts to the thesis that all events are instances of lawful regularities, in a necessitarian view determinism entails that every event is compelled by natural laws to be as it is. This difference, however, is not accounted for in Earman’s original definition, while it seems to be implied in James’ view that determinism “professes that those parts of the universe already laid down absolutely appoint and decree what the other parts shall be”,88 which Earman sought to ‘transcribe’. So, parallel to our discussion of necessity, we might also distinguish two types of ontological determinism, utilising Earman’s definition: Humean determinism and determinism with a vengeance: Humean Determinism: The world w ϵ  is Humean deterministic just in case for any w’ ϵ , if w and w’ agree at any time, then they agree at all times.89

87 See Molnar 1974, pp. 106-108. 88 James 1956, p. 150, my italics. 89 Compare Earman 1986, p. 13, small type face added for consistency with the formal standard of this volume. See n. 93 in this volume.

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Determinism with a vengeance: The world w ϵ  is deterministic with a vengeance just in case for any w’ ϵ , if w and w’ agree at any time, then they are compelled to agree at all times by the natural laws that all the worlds in  share. Note that determinism with a vengeance does not presuppose that all the facts in w and w’ are physically necessary with a vengeance, it is sufficient that they are simply necessary with a vengeance, i.e. it is possible that there are possible worlds with the same laws as the actual in which some of the facts in w and w’ do not occur and vice versa, given that the initial conditions can vary. For this reason, physical necessity with a vengeance is not relevant to the general argument of this essay, which is why it will be ignored for the rest of this text. Geert Keil also distinguishes between a Humean and a necessitarian type of ontological determinism, which differ in the sense that only the latter warrants a modal force which compels the events to occur. Keil also holds that a notion of PAP can be preserved in such a view because the laws do not compel the agents’ actions, which belong to the Humean base over which the laws supervene.90 It has often been recognised by Humeans that an application of Humeanism to the debate about free will might have an import into the free will debate,91 and to spell out this import is the very aim of this book. So does Earman's definition of determinism really satisfy James' account of determinism, which it was meant to merely transcribe, if we believe Earman? By now, it should be fairly obvious that it does not do so necessarily. If you apply a regularity theory of laws of nature to Earman’s definition, to say that the world is deterministic is simply to say that every fact in the world is an instance of a lawful regularity. That is not the same as to say that determinism “professes that those parts of the universe already laid down absolutely appoint and decree what the other parts shall be”. Whereas the toothless Humean necessity simpliciter does not yield this result, necessity with a vengeance obviously does.92 In Armstrong's theory of 90 See Keil 2007, pp. 123-128. But on this basis, Keil proposes an ability-based notion of freedom, which will not be discussed any further in this essay. 91 See e.G. Swartz 2003, pp. 116-118. 92 At least it is meant to yield this result. Bas van Fraassen offered a thorough analysis as to why to his view the regularity account does not yield the desired result.

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laws of nature, an event that falls under a law of nature is necessitated by the law to be the way it is. Armstrong regards laws to be complex universals consisting of at least two monadic (or simple) universals which are normal properties and a necessitation relation (which is a universal itself) between these properties. So laws take the form N(F,G)93 where N is the necessitation relation and F and G regular properties. The whole complex N(F,G) then is construed to be a universal itself. As the law itself is a universal, it is instantiated in each and every instance of the law to the effect that anything's being an F necessitates its being a G in virtue of its being an F.94 We will return to Armstrong's account and the question of plausibility later in the text, but it is obvious here that in a very important sense, an Armstrongian law, in contrast to laws of the regularity account, does force its instances to be the way they are. This necessitation rules out any physically impossible events in a rather different way than the laws of the regularity account. The interesting question then, and indeed the whole point of this book, is to investigate if determinism with a vengeance and Humean determinism are likewise compatible with free will. In chapter 4, I will argue for the claim that the first is not compatible with libertarian free will, whereas the latter is.

1.3.1 DETERMINISM IN QUANTUM THEORY Now we have had a look at the conceptual aspects of defining ontological determinism in a hopefully satisfactory way, let us turn to the question whether there is any reason to believe that ontological determinism, regardless of the dispute over how to define it, is actually true. After See van Fraassen 1989, p. 104-109 for more details. We will return to the question of how plausible the necessitarian account is in chapters 2.1.1 and 2.1.2. 93 Unfortunately, there is no common standard amongst authors concerned with laws of nature regarding the question what to italicise. In order to avoid inconsistencies, I will stick to Theodore Sider’s (See Sider 1992) usage: predicates, universals, relations, instances of universals, and propositions will be set in italicised capitals, particulars and possible worlds will be set in italicised small-print letters, as will be instants of time. Direct quotations will not be altered, unless indicated. 94 See Armstrong 1983, p. 85-99.

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having read the last paragraph, you might ask why we should deal with the truth of determinism at all, given that the last chapter was devoted to the yet to be elaborated suspicion that free will is only at odds with a kind of determinism that is implausible, whereas a weaker, but more plausible Humean version of determinism is not. We shall look at whether determinism is true mainly for two reasons. Firstly, if determinism was false, we could spare us the pain of the next chapter that is devoted to defend a Humean stance of laws of nature and hence Humean determinism that seems to come with the regularity theory, and to attack the stronger necessitarian determinism even further by hinting at the implausibility of its supporting theory of laws of nature. Secondly, it serves as a reference point for the discussion of classical libertarianism which rests upon the falsity of determinism, and for the particular attacks against libertarianism shown in Chapter 4 below. If determinism was clearly false, then classical libertarianism could not be attacked from this side. But if determinism is true, classical libertarianism cannot be. This is the motivation that stands behind proposing with Humean libertarianism a theory of free will that is independent from the truth of determinism but still hopefully preserves a stronger notion of freedom than in classical compatibilism. One important aspect of determinism has to be noted. Determinism of an ontological kind is a metaphysical thesis. It does not become one by positing metaphysical entities such as a Laplacian demon, but because as a theory it is empirically untestable95 and, more importantly, because it contains ontological claims about the existence or non-existence of nomological necessity in nature. Because determinism in untestable, even if all our sciences suggested that there are undetermined processes in nature, it would always be possible to argue from the armchair that all alleged indeterministic events were not indeterministic at all, but that there are in fact yet undiscovered or indeed on principle unobservable or inconceivable hid95 Its untestability sets it apart from everyday empirical theories, which are likewise unprovable due to their inductive reasoning, but determinism is also unfalsifiable. Geert Keil suggests that the only way to falsify determinism would be to rerun the entire history of the universe and see if there are any deviations from the first run. That, of course, is entirely impossible. (Keil 2007, pp. 35-36). John Earman likewise suggests that determinism is a metaphysical theory, but that this fact does not make determinism mysterious (see Earman 1986, p, 10).

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den variables that in fact determine these events. Such a thesis may be implausible nonsense, but it could not on principle be refuted by empirical evidence. So why bother to look at science at all, if determinism cannot be proven or refuted by it? Because, pace scientific antirealists, if all empirical evidence suggest the falsity of determinism, then philosophers should not on pain of embarrassing themselves contradict science. Or if indeed our best current scientific theories unanimously suggested that there is no reason to think of any event as being caused indeterministically, we philosophers should not ignore these scientific results and for whatever reasons we may have simply state that the scientists are wrong. So, in lieu of real proof or refutation of determinism, it is still informative and indeed necessary in order not to embarrass ourselves to look at the hints science gives us. For this, we will consider quantum theory, which is important for two reasons. It is widely conceived of as an indeterministic theory and because of that, it has been seen as the most promising solution to the problem of free action in an otherwise deterministic universe. Quantum theory has been seen as a last resort for defendants of libertarianism ever since Pascual Jordan’s amplifier thesis.96 As it became more and more obvious that mind-states and brain-states are at least strongly and positively correlated, scientists and philosophers reached for quantum physics to secure indeterministic events in the brain that should secure, to cite and abuse Daniel Dennett’s lovely phrase, some elbow room97 for free will to operate. We will discuss Jordan and a more recent theory invoking quantum effects in the brain, the Orch-OR-theory of free will by Roger Penrose and Stuart Hameroff98 and their problems in chapter 4.1.2 when we turn to the problems of libertarian theories. To present the reason why quantum theory can be interpreted in a way that it permits indeterministic events is a hard task and often, this leads to massive misunderstandings about the nature of the theory. So before we turn to Pascual Jordan’s theory and indeed to the bulk of libertarian theories, of which some reach for quantum mechanics to secure indeterminism, 96 97 98

See Jordan 1938. The amplifier theory will be discussed below. See Dennett 1984. See e.g. Penrose & Hameroff 1996.

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let us take a good look at whether quantum theory actually is an indeterministic theory at all. Some problems arise in presenting quantum mechanics, apart from its complexity. Neither is there a single unanimously accepted theory of quantum mechanics, nor are these different varieties of quantum mechanics easily understandable, nor is it usually the case that philosophers who use quantum mechanics in their arguments for or against determinism or libertarianist theories of free will get it right. A brief look at the development of quantum mechanics should help to shed some light on this mind-boggling part of physics.

1.3.1.1 COPENHAGEN-LIKE THEORIES OF QUANTUM MECHANICS As seen above, quantum mechanics is often seen as a theory that allows genuine indeterminism in nature as it permits merely a probabilistic forecast of some micro level events. But this view is over-simplifying on two levels. Firstly there is the fact that the wave function, which describes the state of the particular micro-physical systems in question, is in itself perfectly deterministic,99 and secondly there is the fact that the indeterministic Copenhagen theory of quantum mechanics is not the only theory of quantum mechanics available. In fact, there are even more than just one Copenhagen-like theory. I will not delve into the maze of possible and actual subtle differences in all of the different theories, nor do i try to give a full account of quantum theory. What we have to establish here for later use in chapters 3 and 4 is a basic understanding of what is going on in the quantum world and how the two most prominent schools of thought differ from each other. Representing the indeterministic theories we will consider will be summarised as Copenhagen-like theories, the deterministic varieties will be represented by the Bohmian hidden variables theory. Other versions of quantum mechanics such as e.g. the multiverse interpretation by Hugh Everett100 and his followers are left out for the sake of brevity, as are all those details in quantum mechanics that are of no direct significance for the question of whether the quantum world is deterministic or not.

99 See Albert 1994, p. 34. 100 See e.g. Everett 1957 for details.

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The development of quantum theory started when in the year 1900 Max Planck discovered a baffling property of heat radiation. Heat radiation is the light emitted by heated bodies. The properties of the light such as its colour for instance do not only depend on the temperature of the glowing body, but also on the condition of the body’s surface. In order to achieve a neutral light you have to find a way of getting rid of the influence of the surface, which is possible with so-called black bodies. These black bodies are in fact just hollow bodies and the striking effect that they display is that when heated, the light inside the black body is such that all the influence the surface of the body has on light emission is eliminated. If you now punch a tiny hole in such a black body, the effect this hole has on the nature of the light inside the black body remains negligible, but the light emitted through that hole into the outside world is almost perfectly neutral, that is, it is almost “ideal light”, bare of all influence the surface of the light source might have.101 When Planck tried to interpret the properties of heat radiation, he could not make light of it in terms of the wave theory of light, which had been the orthodox interpretation of the nature of light since Thomas Young’s famous double-slit experiment, where he demonstrated that light shows a certain behaviour that could only be explained by it having the form of a wave.102 So Planck postulated that changes in energy of radiation such as light come in discrete levels. He described changes in energy of light in his famous formula E=hf, in which E stands for Energy, f for frequency and h is Planck’s famous constant. Planck thus postulated that light comes in discrete quanta, in photons.103 The wave theory of light on the other hand was very successful to explain some effects that light displays that are equal to the effects that other waves exhibit, those in water being the easiest to observe. The idea that light also sometimes seemed to behave like particle-radiation as Planck discovered when he described heat radiation led to heated discussions in the scientific community. Another piece of evidence for the particle theory of light is the socalled photoelectric effect which Einstein tried to make sense of. The photoelectric effect is the effect that light can knock electrons out of a sheet of metal on which a ray of light is cast. In order to explain this effect in terms 101 See Planck 1900, pp. 237-245. 102 See Young 1802, pp. 25-48. 103 See Planck 1900, pp. 239-240.

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of light as a wave, you have to assume that the effect needs some time, so that the wave can slowly rock the electron like a child on a swing until the electron finally changes its energy level and is knocked out of the atom. But this contradicts observation, as it can be shown that the electrons are knocked out of the sheet of metal immediately once light hits it, whereas a process of slowly bringing the electron up to speed would need more time. Einstein used Planck’s idea of light as quanta are able to explain this effect quite successfully.104 It is hard to understand how light sometimes shows the behaviour of particle radiation and sometimes the behaviour of electromagnetic waves. During the next years, these and other discoveries led to huge changes in the understanding of the very nature of nature. We will skip further details of the development of quantum mechanics here in order to avoid becoming to verbose. The most direct way to grasp what quantum mechanics is about is to consider its mathematical representation with which a lot of the essential concepts can be elucidated. To understand quantum mechanics more deeply, we cannot avoid taking a brief look at its mathematical representation. While the Schrödinger equation for any physical system in all detail is far too complex for a philosophical essay which is aimed at an audience of people interested in the free will debate and written by a non-physicist, it is nevertheless possible to explain some key concepts by discussing their mathematical formulation.105 The core of quantum mechanics is the mathematical calculus to describe the dynamics, i.e. the temporal development, of a quantum mech-

104 For Einstein’s paper on the photoelectric effect, see Einstein 1905, especially pp. 133 and 145-148. 105 The best introduction to the formal aspects of quantum mechanics suitable to be read by anybody not engaged in physics or maths on a professional level is David Z. Alberts excellent 1994 book Quantum Mechanics and Experience, from which the bulk of information regarding the formal aspects of quantum mechanics for this essay has been taken.

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anical system106 called the Schrödinger equation.107 This equation describes the temporal development of a physical system’s variables such as position and momentum. In quantum mechanics, a physical system is represented as a vector space with certain properties. Any particular physical state of that system is depicted as a particular vector within that space. The set of all possible vectors that fall within that vector space is the set of possible physical states that the system can be in. A vector space can have any dimension. Which dimension a particular vector space can have is determined by the number of directions that vectors that point in mutually perpendicular directions can have. Consider a standard two-dimensional vector space such as any old two-dimensional coordinate system for instance. For any vector within that space, only one direction is possible that is orthogonal to that vector. The vectors within the vector space that represents a particular physical system can have, depending on which physical state they represent, very different properties. Take for example a vector space that describes only the location and momentum of a particular physical system. Directions and velocities come in a continuum of possible values, and so do do the vectors of the according vector space. Any observable property of the physical system is represented by an operator. An operator is nothing more than a permutation instruction for all vectors in a particular vector space. It is a mathematical prescription how to change all the existing vectors in a particular way prescribed by the operator. An operator applied to an existing vector thus yields another vector. It can for example carry the instruction of adding +3 to the length of any vector or change its direction by any specified degree or a combination 106 In theory, there is no restriction in size for of counts as a quantum mechanical system and indeed it is a very interesting question why macro objects such as people, cats and planets do not show quantum effects. Anton Zeilinger and his research group are working on trying to produce quantum effects with bigger and bigger molecules, e.g. fullerenes, which consist of 60 carbon atoms (See Arndt et al. 1999, pp. 680-682). 107 If the Schrödinger equation is to be counted as a natural law it forcefully refutes the claim put forth for example by Geert Keil (See Keil 2007, p. 29-30) that natural laws are status laws and not dynamic laws. The Schrödinger equation is one of the most fundamental equations physics has to offer and still is quite clearly a dynamical law. In that paragraph Keil also makes the mistake of confuting dynamic laws with universally quantified conditionals, while these conditionals can clearly express a status as well as dynamics.

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thereof. Note that the resulting vectors are again vectors that fall within the given vector space. A vector that after transformation by an operator points in the same direction as the zero vector is called an eigenvector of that particular operator. That means that an eigenvector of an operator is the vector resulting after transformation of a zero vector via an operator when the vector merely changes its length by a specific factor that is called the eigenvalue. Since in quantum mechanics, physical states can be represented by vectors and observable properties are represented by operators, the state of a physical system represented by an eigenvector of the particular operator is called an eigenstate. Thus if any quantum mechanical system is in an observable state, its mathematical description takes the form of an eigenvector of the according operator. 108 Some properties a physical system can come in mutually incompatible pairs as described by the Heisenberg uncertainty principle. Take location and momentum of a quantum mechanical system as an example. Once a physical system is in a definite state regarding its position, its momentum is undetermined by a degree established by the accuracy the position was determined. This mutual dependency of these incompatible properties is obviously reflected in their mathematical description. The particular vector that describes the actual position the system occupies is a sum of the vectors that describe the system’s possible momenta under the permutation of a particular operator yielded by the definite location vector.109 Note how beautifully that shows us what superposition means – a concept we will have to consider again in the discussion of the Orch-OR-theory of free will. A system’s having a particular definite location is a superposition of its possible momenta, such that the system has no definite momentum at the same time is has a definite location. The very moment someone then tries to measure the exact momentum of that very same system, the measured momentum is a sum of all the possible positions the system can occupy under permutation of an operator, which, as you remember, portrays a particular observable property: the system’s definite measured momentum. That is why you cannot circumvent the Heisenberg principle by measuring momentum and location each at a time to yield a description of both momentum and location for a quantum mechanical physical system at a given time. The very moment 108 Albert 1994, pp. 29-31. 109 See Albert 1994, p. 33.

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you measure one of the incompatible pair of properties, the system is in a superposition of the other property and hence loses its having a definite value of that second property. Now we have come to the very core of why quantum mechanics is even of interest to us: the indeterminism of the Copenhagen theory. The Schrödinger equation in general is not indeterministic at all, it gives a perfectly deterministic description of the physical system in question in the sense that is does not contain any probabilities. Probability only enters the mathematical representation when a particular solution of the Schrödinger equation is yielded by measurement of one of the system’s properties. That is, because measuring the system’s location yields the superposition of it’s possible momenta, the calculus yields probabilities for any particular momentum the system can have. Suppose the vector that denotes the system’s location is |loc.>, which is a superposition of the system’s momentum. If the momentum then is to be determined by measurement, that is, if the exact vector that denotes the system’s actual momentum | mom.> is to be determined, the outcome of the measurement process is a matter of probability with a value below 1, according to the Heisenberg uncertainty principle.110 Measurement of a state of a system in superposition is the only probabilistic element in the mathematical description of quantum effects. Probability thus enters the quantum world only through measurement, that is through interaction with other physical systems. The idea that stands behind all of the Copenhagen-like theories of quantum mechanics is, then, that it is the indeterminate nature of nature itself that accounts for the probabilistic outcome of the measurement of a superposed aspect of a physical system, not, as in the hidden-variables-theories we will consider below, a lack of knowledge of our representation of quantum effects. Equally, superposition in Copenhagen-like theories means that the superposed property of a system actually is undetermined. To understand this more accurately, we have to introduce two key concepts here: wave function and collapse. A wave function, or Ψ-function, as it is often called, of a quantum system describes the state of a physical system in configuration space. Configuration space is the vector space that comprises all the 110 For the technical details, see Albert 1994, p. 35.

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physical information of all parts of a physical system. The wave function carries all information about the vector space of that physical system and the particular ways these vectors depend on each other, that is, which state is a superposition of another state. The wave function also carries information about how the physical system will behave over time, which behaviour is, surprisingly, strict.111 The Schrödinger equation in contrast is a general equation that describes the dynamics of quantum physical systems in a strictly deterministic way. That is why some scientists regard quantum mechanics as the physical theory which features the best functioning deterministic dynamical law of all physics, although it is deemed to produce undetermined results at times of measurement. 112 But the wave function also entails the probabilities of all the possible outcomes of all possible measurements. Thus the wave function as such is not probabilistic at all, it merely entails all the probabilities for all the possible values of superposed properties when measured. Such a measurement, whose outcome is probabilistic and yields one definite measured value of the measured property, is termed a “collapse” of the wave function. It is a matter of dispute within the group of proponents of Copenhagen-like theories how to interpret this collapse. As a matter of fact, Niels Bohr, one of the founders of the standard Copenhagen theory, argued that there is no collapse in the real world, as the Ψ-function serves only as a symbolic description of a physical system and not as a realistic representation in his view.113 What connects all Copenhagen-like theories is its stochastic element at times of measurement. Unlike folklore has it, quantum mechanics does give us a deterministic mathematical instrument, the Schrödinger equation. Taken as a dynamical law, it is in fact even one of the finest and most accurate deterministic laws around. At a moment of measurement this deterministic calculus collapses and yields a probabilistic result. As such, quantum theory in Copenhagen-like fashion also provides us with one of the very few genuine indeterminisms in physics. But as mentioned above, this is not the only way to interpret quantum mechanics. This will be looked at in greater depth in the following. 111 See Maudlin 2002, p. 215. 112 See Walter 1999, p. 43-45. 113 See Faye 2008.

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1.3.1.2 BOHMIAN HIDDEN VARIABLES THEORIES The idea that nature could have an indeterministic element is a truly thrilling one for every classical libertarian. If there really was some element of nature that behaved indeterministically, this would serve to refute any argument against libertarianism that refers to the incompatibility of free will and determinism and presumes that determinism was true.114 But unfortunately for the libertarian, the idea that there could be genuine indeterminism at work in physics did not, unsurprisingly, please every physicist. Popper described the proposal that microphysics could have an indeterministic aspect as a shock to early twentieth century physicists, who (wrongly, in Popper’s view) adhered to a dogmatically deterministic world view ever since Newton’s mechanics.115 So the proposal that physics might be indeterministic at a micro level at moments of interaction met serious challenges. David Bohm held a view comparable to Einstein’s116 insofar as he is similarly sceptical about indeterminism and tried to show that orthodox quantum mechanics is not complete as it requires what is now commonly being called “hidden variables” to retain determinism. The core idea that unites all of the so-called hidden variables theories that followed Einstein’s dislike of indeterminism was that all the strange and seemingly indeterministic phenomena that the Copenhagen theory suggested were the effects of unobservable variables that could explain away all the oddities of the indeterministic versions of quantum mechanics. In this paper, David Bohm’s theory shall stand pars pro toto for all hidden variables theories, since it is the best known of all theories of quantum mechanics which try to eliminate indeterminism by hidden variables. Whilst Bohm’s theory explains away the indeterminacies, it nevertheless accepts non-locality, thereby conforming to Einstein’s critique of indeterminism but dissenting from his ideas concerning non-locality.117

114 115 116 117

Let us for a moment ignore the possibility of a local determinism. See Popper 1982, p. 26 For the locus classicus, see Einstein, Podolski, and Rosen 1935. See Maudlin 2002, p. 121.

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We will treat Bohmian mechanics as we treated the Copenhagen-like theories of quantum mechanics. Whereas technical details are omitted, we will concern ourselves merely with the general ontological commitments of Bohmian mechanics. Tim Maudlin elegantly reproduces Bohmian mechanics along three main principles in which it diverges from the classical (i.e. Copenhagen-like) picture. The three principles are: I The properties given in the wave function that describes the dynamics of a physical system are not all the properties the system has. That is, there are properties a system can have that are not given in it’s wave function, like a definite location and a definite momentum at any time. In the mathematical description this is represented by the fact that a system can have properties represented by vectors which are not eigenvectors of the according operators. As only eigenstates of an operator are observable, the states that are not eigenstates of the according operator and which are not given in the wave function reflect physical properties a system has (like a definite momentum when its position is measured) that, although existent, remain unobservable, thus “hidden”. II In contrast to the classical picture, the wave function does not collapse at times of measurement or interaction and thus the physical system always develops according to the Schrödinger equation, which does not apply when the wave function collapses within the Copenhagen theory. III As discussed above, even the Schrödinger equation is deterministic as long as the wave function does not collapse. As no collapse occurs in Bohmian mechanics, the dynamics of a physical system remain deterministic at all times, even when measured and certain properties incompatible to those measured disappear into unobservable obscurity (those properties which are not eigenstates of the operator in question).118

Now you can see why the name “hidden-variables-theory” is misleading, as what is hidden are no variables in the strict sense of the word, but merely properties of the system that remain unobservable but which develop deterministically, which is why Maudlin calls these “hidden para118 See Maudlin 2002, p. 116-117.

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meters” in contrast to “variables”.119 Bohm’s theory deviates from the classical theory not only in the way the calculus is interpreted but also, and more importantly, on the ontological level. Physical systems do have a specific particular momentum and location at all times, in the same way as they have specific values for all mutually incompatible properties of orthodox quantum mechanics at all times. Any appearance to the opposite is due to restrictions of experience. But Bohm also introduces a new kind of entity to the world: wave functions. These are not merely abstract mathematical entities in Bohms’ view but real physical entities such as force fields that drag particles around on a micro level. Thus the term “wave function” describes an entirely different thing in Copenhagen-like theories than it does and in Bohmian theories.120 These Bohmian wave functions, as they are concrete physical entities, never collapse in the way they do in Copenhagen-like theories of quantum mechanics. Nevertheless, the bulk of the mathematical description remains identical in these two standard ways of thinking about the quantum mechanical world. In the Bohmian theory, a momentum of a particle is a function of the position of a particle as obtained by the wave function that pushes the particle around.121 Thus, not only does the particle actually have a definite location and momentum simultaneously at all times, they also can be exactly calculated which thereby secures determinism. In Bohmian theories, it is at least on principle possible to calculate at any time the position and momentum of a particle and predict its wave function for any time later with absolute certainty.122 How is it possible that the Bohmian and the Copenhagen theory yield the same predictions?123 This is due to our restrictions in measuring both position and momentum of a particle. Bohm’s theory assures that if the only thing that is given to our experience at a particular time is a particle’s 119 See Maudlin 2002, p. 117. 120 See Albert 1994, p. 135. 121 See Maudlin 2002, pp. 120-121. 122 See Albert 1994, pp.136-137. 123 The fact that the Bohmian and the Copenhagen theory yield the same predictions might suggest that these are not two different theories, but only two different ontological interpretations of the same theory. I will not take sides in this question; my use of the word “theory” does not indicate that I have any conviction regarding this case.

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momentum and the wave function, yet we are unsure about its position, the Bohmian theory yields exactly the same probabilities for the particle inhabiting various positions when we undertake a measurement as standard quantum mechanics gives us, only that these probabilities really are just epistemic in the sense that the particle always has a single definite position that is deterministically determined by its wave function, yet is not entirely open for us to calculate because we lack crucial information.124 This differs substantially from the indeterminacy of the Copenhagen theories, where that particle simply would not have a definite location until it is being measured and the outcome of that measurement would be a probabilistic affair, not because we lack information, but because there is nothing in the world that information could be about.125 We will leave Bohm and indeed the whole debate about quantum mechanics here, as no amount of detail yet to be told about it could possibly help us to understand the various theories about free will that will be discussed below. The conclusive experimentum crucis between the Copenhagen-like theories and Bohmian mechanics has, provided that this is even possible, yet to be designed and performed, or perhaps both theories are to be replaced by a final quantum theory, if any physical theory can ever be considered as final. At any rate, by now it should be clear that quantum theory is by no means unanimously seen as an indeterministic theory. Only at times of interaction or collapse of the wave function it can be seen to produce indeterministic results, and even then only if you adopt a theory of a Copenhagen fashion, which you could not call “unchallenged” by any reasonable standard. So at the end of the day, all the humble philosopher can maintain is that it might be possible that there is genuine indeterminism in nature, depending on what interpretation of determinism prevails. At the end of the conceptual considerations of determinism, we hoped for a clear signal from physics whether physicists consider the world to be deterministic or not. All we have learned from the above passages is that considering contemporary physics, the world may be deterministic, as well as it may not. So a proponent of libertarianism cannot wiggle himself out of the headlock of compatibilists or hard determinists by simply stating that 124 See Albert 1994, pp. 138-139. 125 See Maudlin 2002, p. 119.

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according to contemporary physics the world is not deterministic. This result is problematic for those libertarians whose theories of how free will operates rely on indeterministic quantum effects. But, even a determinism that does not rely on strong metaphysical necessity could be refuted in case any of the counterexamples listed above were conclusive, as nature then just wouldn’t be as orderly as commonly assumed, regardless of whether it is orderly by force or just is.

Before we go on to the next chapter, let us take stock. Firstly, we have seen that ontological determinism is widely regarded as a metaphysical thesis about the impossibility of certain future events. Thus, as it is a modal statement, it needs a modal force to secure the impossibility of other future events except the ones that do happen, or vice versa the necessity of the future. Even John Earman in his brilliant account of determinism leaves this modal force out in his analysis which thus either has to be backed up by an additional modal force which presumably comes from necessitarian laws, or hi analysis simply is reduced to the claim that nature is strict, and just happens to be strict. But such a claim obviously falls short of William James’ intuitive picture of the the future as a cast-iron unalterable block that Earman used as a starting point in his analysis: What does determinism profess? It professes that those parts of the universe already laid down absolutely appoint and decree what the other parts shall be. The future has no ambiguous possibilities hidden in its womb: the part we call the present is compatible with only one totality. Any other future complement than the one fixed from eternity is impossible. The whole is in each and every part, and welds it with the rest into an absolute unity, an iron block, in which there can be no equivocation or shadow of turning.126

We then had a look at the scientific picture of the strictness of nature and found it inconclusive whether determinism is true or not. Science has not yet decided whether determinism is true or if there could be genuine indeterminacies in nature. Thus, neither hard determinists, nor 126 James 1956, p. 150.

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compatibilists, nor libertarians can use present physics as a conclusive argument for their point. The important question that remains then is how the different types of theories of laws of nature fare. Whatever theory of laws of nature prevails decides which kind of determinism remains tenable: Humean determinism or determinism with a vengeance. In the following chapter we will now consider some contestants. In the end, I can hopefully show that a best system view of any kind, which can only support Humean determinism, is the most promising. What this entails for libertarianism will be seen in chapter 4.

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2 NECESSITY AND LAWS OF NATURE In chapter 1 we have discussed how to define determinism and whether our best current scientific theories suggest that it is true or not. We have seen above that the notion of determinism is inextricably tied to the notions of necessity and natural law. By now it has become more than just a sneaking suspicion that one’s choice of theory of laws of nature reduces the set of available theories of determinism to choose from to those that are compatible with the chosen theory of laws of nature. We have seen that the regularity theory yields a different version of determinism from the sense of determinism that needs a modal force. Before we turn to libertarianism in its various guises and how it actually in detail copes with the threat posed by ontological determinism, we will take a quick look at some theories of laws of nature. The theories of laws of nature covered below fall into two subgroups. Necessitarian theories of laws of nature maintain that natural laws necessarily entail their instances, while in Humean theories, modal forces in nature are rejected. In contrast to giving an exhaustive list of all the actual theories and their main problems as well as a conclusive answer to the question what a law of nature actually is, we will focus here on the ontological commitments of these theories. The restrictions of writing a book of a manageable size about free will forbid the thorough defence of one theory of natural laws and the equally thorough refutation of all the others. This essay does not aim at offering a comprehensive comparison of all the currently available theories of laws of nature, trade off all arguments for or against these positions, and in the end provide a definitive answer which position to favour. This is work for a very extensive book of its own. The aim of this essay is simple: the first step was to see that theories of determinism differ according to the theory of natural laws you put in, the second step will be to show that Humean accounts of laws of nature are hopefully defendable, and the third step will be to demonstrate that with this ontological background, a rebuttal of the most prominent attacks on libertarianism is at least possible. To achieve this, it is not necessary to carefully list all the necessitarian views and meticulously enquire their strengths and

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weaknesses compared to Humean accounts, but simply to give an overview of the available options and the metaphysical cost of necessitarianism that can be saved if Humeanism of any sort is possibly tenable. Accordingly, the bulk of this chapter will concern a defence of Humeanism, whereas necessitarian views will only be sketched relatively briefly to outline the opposition. If Humeanism is tenable, then there is no need for the ontologically more demanding necessitarianism. The central question any theory of laws of nature has to answer is how to distinguish laws from non-laws. For any theory that defines laws of nature as a certain set of sentences or propositions such as orthodox Humeanism, this amounts to the question how the sentences that are laws differ from those which are not. In any theory that treats laws of nature to be general facts in nature rather that sentences about them, the above question centres around the problem of how law-like facts differ from accidental facts. It is impossible to give an exhaustive and undisputed list of properties that laws in any theory share, as some property vital to one theory might be rejected in another, or some properties might trade off one against the other, and different theories of laws of nature give different answers to how to manage such a trade-off. Bas van Fraassen, who gives a list of twelve criteria, also states that not all of his criteria needed to be met, but any account on natural laws should respect the cluster of possible criteria as a whole.127 Nevertheless, theories of laws of nature can be identified by answering the question of how they cope with the following criteria I take from an overview by Andreas Hüttemann:128 I

TRUTH: On first sight, this criterion seems to be uncontroversial. Any sentence that is claimed to be a natural law needs to be true, or – if you favour a theory which holds that laws are not sentences – any sentence that expresses a law has to be true. Even if you lay aside any principal doubts whether truth is a meaningful concept, we will see that some-

127 See van Fraassen 1989, p. 26-38. 128 For all the criteria of natural laws depicted here, see Hüttemann 20072, pp. 139141.

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times, this criterium trades off against universality.129 Moreover, it is the case that some facts or sentences that scientists call laws are false, and more disturbingly, known to be false.130 II OBJECTIVITY: For a law to be objective it has to be independent of personal interests, opinions, preferences, and whether or not it is known to be law, i.e. there may be laws that will never be discovered. Note that this criterion can be at odds with pragmatic accounts of laws of nature. 131

III CONTINGENCY: Laws of nature need to be logically contingent. Sometimes this criterion is reformulated as the requirement that laws need to be synthetic truths about our world instead of analytic truths.132 To adopt contingency as a property of laws of nature entails rejection of Quine’s claim that analytic and synthetic statements are indistinguishable.133 IV NECESSITY: This seems to be at odds with the aforementioned criterion, but it is not, at least not necessarily. While the criterion of contingency sought to rule out analytic facts, in many accounts of laws of nature the laws describe necessary facts about our world which are to be distinguished from merely accidental facts.134 In accounts on laws which claim necessity with a vengeance as described in chapter 1.3, physical systems that behave lawfully have to behave as they do. Necessity with a vengeance that accounts for forcing the world to be a certain way is often called “physical” or “nomological” necessity to distinguish it from metaphysical or logical necessity. But we have seen in chapter 1.3.1 that this nomenclature is misleading due to the fact that even Humean accounts of laws of nature which deny the existence of necessity with a vengeance do use the term “physical necessity” to denote 129 See Hüttemann 20072, p. 139. 130 For a seminal discussion, see Cartwright 1983. 131 See Hüttemann 20072, p. 139. 132 ibid. 133 See Quine 1951. 134 See Hüttemann 20072, p. 139. We will see below that indeed a lot of the debate of laws of nature centres around the question how to differentiate between lawful facts and those which are merely accidental.

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existence in every world which shares the same laws as the actual world. Necessity with a vengeance is highly disputed. Firstly, it is disputed whether necessity with a vengeance is a real feature of our world. All regularity accounts on laws of nature dismiss necessity with a vengeance altogether, while some best systems accounts try to integrate some sense of necessity as a property of the best system rather than the world. Moreover, it is unclear what necessity with a vengeance actually is and whether it can do the job it is appointed to.135 So while necessity with a vengeance is seen by many philosophers as a crucial property of laws of nature, regularity theorists deny that it even exists. A word of caution is in order: The terms “necessity with a vengeance”, “physical necessity with a vengeance” and “physical necessity simpliciter” are of my making. As a consequence, when most participants of the debate about laws of nature talk about the necessitarian’s nomological necessity, they mean what I call necessity with a vengeance, i.e. a necessity that can actually compel nature to behave in a certain way. In the rest of the discussion of the various theories of laws of nature, I will adopt my terminology only when there is need for clarification. In general, all necessitarian theories propose some sort of necessity with a vengeance, and the Humean theories do not. Bas van Fraassen, who, as mentioned above, gave a similar list of criteria for natural laws, differentiates between several types of necessity in relation to natural laws. He lists the following ways in which laws relate to necessity:136 A. INFERENCE: This criterion is closely linked to what van Fraassen calls the “inference problem”, which, according to van Fraassen, together with what he calls the “identification problem” riddles the Armstrongian account on laws of nature. Van Fraassen points out that the following inference: It is a law of nature that A Therefore, A 135 See van Fraassen 1989, p. 166 for the so-called inference problem and identification problem. We will turn to these problems in chapter 2.1.1. 136 For all his readings of necessity rendered here, see van Fraassen 1989, p. 29-30.

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Is an inference that needs to be accounted for by some extra factor since it is not warranted by means of pure logic. So something in the laws of nature seems to warrant this inference that appears so intuitively valid. This extra factor could be necessity [with a vengeance]. B. INTENSIONALITY: This relates closely to the above-mentioned aspect of necessity and merely makes the minor point that the phrase “It is a law that” is intensional. As this point bears no significance to our project, we will leave it at simply mentioning it. C. NECESSITY BESTOWED: This and the following relation to necessity helps to distinguish for example David Armstrong’s theory of laws of nature from theories such as the one put forward by Alexander Bird. In Armstrongian necessitarian accounts, the lawful facts about the word are necessary facts and it is the laws of nature that bestow this necessity upon them. In those accounts, if it is a law that Fs are Gs, necessarily any F is a G. This necessity of lawful facts about the world is the above mentioned necessity with a vengeance. D. NECESSITY INHERITED: In contrast to Armstrong and his companions Alexander Bird holds the view that laws of nature not only bestow necessity upon nature but are necessary themselves. Van Fraassen also mentions that necessity inherited entails necessity bestowed, and necessity bestowed entails inference. The interesting question that we will look at below is whether the individual accounts by necessitarians can keep that promise of a chain of entailments. Let us return to Hüttemann’s criteria: V UNIVERSALITY: Usually, for something to be called a natural law it has to have a universal scope. Hüttemann distinguishes four readings of universality.

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A. UNIVERSALITY I: In this sense of universality, a law is universal if it holds for all times and places, so that it is not possible for a law to have spatiotemporal exceptions. If it is a law that no signal travels faster than the speed of light, it is not possible for a signal to travel at superluminal speed e.g. in smith’s garden and nowhere else. 137 B. UNIVERSALITY II: Another way of defining universality is to maintain that a law of nature holds for every item in our world, or in any world with the same laws of nature as in ours. That is to say, if it is a law that all ravens are black, than it is true for every single thing in our world that if it is a raven, then it is black.138 C. UNIVERSALITY III: A third reading of universality is that a natural law is true under all circumstances. Many, or indeed most of the generalisations of matters of fact scientists tend to call laws are not universal in that sense. Most laws hold only in defined circumstances given that no interfering conditions occur. Laws such as the latter are called ceteris paribus laws.139 D. UNIVERSALITY IV: A fourth sense of universality is that a law holds for all values of the included variables. If a law such as the BoyleMariotte-law for ideal gases for example has volume, pressure, and temperature as variables, it holds for any possible definite value of the variables. These different senses of universality are not mutually exclusive. In extreme cases, a law can be universal in all four of these senses or merely in one. VI THE ABILITY TO SUPPORT COUNTERFACTUALS: Counterfactuals are peculiar things. Since their truth conditions are quite hard to nail down logically. It is widely recognised that laws support certain counterfactuals and that hence the ability to support counterfactuals is seen as a criterion to distinguish laws from non-laws.140 The problem is, however, that a circle looms behind this seemingly unproblematic assumption. If a true counterfactual is defined as a counterfactual that is supported by 137 See Hüttemann 20072, p. 139. 138 See Hüttemann 20072, p. 140. 139 ibid. 140 See Hüttemann 20072, p. 141.

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a natural law, and a natural law is defined as a true universal generalisation which, in contrast to accidental generalisations, has the ability to support a counterfactual, the definitions of laws and counterfactuals are circular.141 The way to escape this problem is to find some extra factor that distinguishes natural laws from merely accidentally true universal generalisations, which can explain why laws have the ability to support subjunctive conditionals. As we will see in chapter 2.1, in necessitarian accounts, this extra factor is necessity with a vengeance. VII APPLICATION IN EXPLANATION AND PREDICTION: In the classical account on scientific explanation, the deductive-nomological model by Carl Gustav Hempel and Paul Oppenheim, laws feature as a necessary part of the antecedent conditions of the conditional that counts as an explanation of a particular fact that is given in the argument’s implication.142 Although the DN-account does have serious problems of its own, it is nevertheless plausible that a law of nature can be used to explain or predict the facts it entails.143 Laws play a central role in most accounts of explanation, such e.g. as the unification account144 and the causal account.145

With this cluster of criteria, we have a neat tool to exactly point out the differences between the various theories of laws of nature. Of the abovementioned criteria, the focus will lie on necessity, as this serves as the main differentiator between Humean and necessitarian accounts. In the following sections, I will give a brief overview of the most prominent theories of laws of nature and try to carve out their main weaknesses. I will also try to argue that a broadly Humean account of laws of nature is defendable.

141 See Vollmer 2000, pp. 217-218. 142 For the locus classicus, see Hempel & Oppenheim 1948. 143 See Hüttemann 20072, p. 141. 144 See e.g. Kitcher 1989. 145 See e.g. Woodward 2003 or Strevens 2008.

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2.1 NECESSITARIANISM What use would Humean determinism be for free will if the regularity theory that is needed to support it were implausible? The regularity theory in its various versions was subject to vigorous attacks, most notably put forth by David M. Armstrong, who subsequently developed his own influential account on laws of nature.146 But Armstrong’s necessitarian account is not unchallenged, and neither is it with Michael Tooley’s147 or Fred Dretske’s148 kindred approaches the only necessitarian theory available. Necessitarian theories can be subdivided by their answer to the question whether natural laws that entail their instances with a modal force are themselves contingent or not. Alexander Bird, who gives a joint account of dispositions and laws of nature, insists that laws of nature are metaphysically necessary, i.e. they are the same in every possible world that shares the same fundamental properties as the actual world, because the laws are fixed by the fundamental properties’ dispositional character, which is the same in every metaphysically possible world.149 David Armstrong on the other hand treats natural laws as metaphysically contingent. In his view, natural laws could have been different from how they actually are, because the fundamental properties could behave differently in different metaphysically possible worlds.150

2.1.1 ARMSTRONG, TOOLEY, AND DRETSKE David Armstrong developed his view on laws of nature along the lines of his general ontology. Armstrong made a strong case for universals as properties in his 1978 book “Universals and Scientific Realism”, in which he first outlined the idea of his theory of laws of nature. In 1983 his “What is a Law of Nature” was published in which he developed the idea in greater detail. Armstrong has improved it further ever since in response to various criticisms. The general idea behind Armstrong’s, as well as 146 See e.g. Armstrong 1978, 1983, 19971, and 19972. 147 148 149 150

See Tooley 1977. See Dretske 1977. See Bird 2005, p. 355. See Armstrong 1983, p. 172.

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Michael Tooley’s and Fred Dretske's theories of law of nature is that laws of nature refer to the relations that basic properties bear to each other. In Dretske’s words: Laws eschew reference to the things that have length, charge, capacity, internal energy, momentum, spin, and velocity in order to talk about these quantities themselves and to describe their relationship to each other.151

Since David Armstrong’s theory is by far the most advanced and detailed of the three, we will focus on his theory rather than Tooley’s and Dretske’s. Armstrong’s basic ontological commitment concerning properties is that properties are repeatable universals that we have an a posteriori epistemical access to via our best science. That means that no property can be a real property unless science tells us that it is real, thereby connecting the idea of scientific realism with a theory of properties. Armstrong thus consequently denies that every predicate of our language refers to a genuine property. He holds that properties which can be known a priori are no real properties and that there are many properties yet unheard of. He devises a simple test to answer the question whether a property is a real property: if it has been discovered a posteriori by science, it is a real universal, if not, it is not.152 Armstrong is an Aristotelian regarding properties, i.e. he denies that universals have any existence beyond their manifestations, that uninstantiated universals are impossible.153 Universals in Armstrong’s sense have to be instantiated in order to exist. That does not entail that a universal ceases to exist when its last instance is destroyed, or only exists for the period of its instantiation. For a universal to be real it suffices that the universal is instantiated at some time past, present or future. Thus there are no uninstantiated universals, and all the universals there are have to have been instantiated at some point in the history of the universe.154 Furthermore, Armstrong denies disjunctive as well as negative universals on the ground that one could easily manufacture an infinite number of 151 152 153 154

Dretske 1977, p. 263, original italics. See Armstrong 1983, p. 83 and 1978, p. 11. See Armstrong 1983, p. 83. See Armstrong 1978, p. 9.

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artificial universals if negative or disjunctive universals were allowed.155 Furthermore, it would be easy to construct such universals in an a priori way, as you could simply invent countless negative properties that just any particular in the whole universe have. Thus the restriction to an a posteriori context of discovery helps to reject non-kosher universals. In special cases Armstrong allows universals that violate some of the conditions shown above as “quasi-universals”. 156 Universals can come in a variety of fashions in Armstrong’s view. There are simple universals which are simple properties such as having a mass of 10.2 kilograms or polyadic universals which are relations between a certain number of particulars. Moreover, Armstrong admits higher-order properties which in turn can be simple or polyadic. Higher-order universals are properties of properties, such as relations holding between simple universals for example. In this case, the first order universals between which the n-adic second order universal or relation holds serve as second order particulars. Thus, a universal of lower order can be a particular in the sense that it is an instance of a higher-order universal. Take for example any relation R that bears between two particulars, Fa and Ga, which results in a complex state of affairs R(Fa,Ga). On a higher level, there can be a corresponding relation R that bears between the universals F and G, which act as particulars of a higher order here, resulting in the following state of affairs: R(F,G). Armstrong now holds two interesting views: firstly that the complex state of affairs R(Fa,Ga) is a proper instance of R(F,G), which acts as a complex universal here, and secondly that relation R is the very same in both complex state of affairs R(Fa,Ga) and R(F,G).157 This will become important to us for Armstrong’s answer to a particular problem of van Fraassen’s, which we will turn to below. Armstrong then goes on to define a natural law as a relation between universals, a necessitation relation, to be precise. In Armstrong’s view, it is a law that all Fs are Gs if the instantiation of F necessitates the instantiation of G. By instantiating F, a particular is necessitated to instantiate G in virtue of its being an F. The trick is then that the law itself is a universal of 155 See Armstrong 1978, pp. 20 and 23. 156 See Armstrong 1983, p. 79. 157 See Armstrong 1983, pp. 82-84.

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higher order, a polyadic universal which holds between universals of a lower order serving as particulars. Armstrong introduces the notation of N(F,G) for a simple law of nature between the universals F and G, where “N” stands for the necessitation relation. Thus the law of nature that holds between F and G necessitates all Fs in all physically possible worlds to be Gs.158 One of the claims Armstrong has to prove is that N(F,G) really entails the universally quantified conditional that all Fs are Gs. If it is a law that F necessitates G, it cannot be possible that there is an F that is no G, unless some inhibiting factor occurs. Armstrong maintains that if it belongs to the nature of F to necessarily bring G with it, then all Fs are Gs.159 Bas van Fraassen on the other hand identified a problem here. He points out that Armstrong has not yet answered the question what exactly this curious necessitation relation N is, and if he did, he could not show how the natural law entails the universal conditional. If Armstrong could demonstrate the latter, he would render the other problem of defining what N is insoluble. Van Fraassen calls these Problems the “identification problem” and the “inference problem”, which he takes to form a dilemma. In van Fraassen’s own words the two problems are: Identification problem: which relation between universals is the relation → (necessitation)? Inference problem: what information does the statement that one property necessitates another give us about what happens and what things are like?160

This problem is a worry that simply by calling a relation a “necessitation relation”, Armstrong has not yet identified the relation properly or shown that it may be reducible to a different, more intelligible relation, or how, given that the relation is identified properly, the fact that if F necessitates G entails that every F is a G. Something about the necessitation relation has to warrant such a conclusion, and this justification cannot merely 158 See Armstrong 1983, p. 85. 159 ibid. 160 Van Fraassen 1989, p. 96.

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consist of giving the relation a name that sounds as it would do the trick.161 Van Fraassen’s dilemma amply illustrates the metaphysical cost at which Armstrong’s account comes. Marc Lange poses the same central concern in form of the Eutyphro question: “Are the laws necessary in virtue of being laws, or are they laws in virtue of being necessary?”162 Unsurprisingly, Armstrong answers this question according to the first part of the Eutyphro question. So the law’s necessity must in some way be grounded in the relation the universals bear to each other. As a result, logical necessity is out of the question. If it is a law that Fs are Gs then in Armstrong’s theory it must be the case that F-ness necessitates G-ness and this should entail that any F is necessarily a G. But how could a contingent necessitation relation account for the necessity of the law’s consequences? Let us for a moment grant that there is a nomic necessitation relation between F-ness and Gness, and that any necessitation relation between universals must be accompanied by a regularity that all Fs are Gs. In virtue of which necessity, van Fraassen, Lange, and Lewis ask, can a contingent necessitation relation make the fact that all Fs are Gs necessary?163 David Lewis remarks that calling a relation “necessitation relation” and the necessity involved “nomological necessity” does not justify the inference that necessarily, every F is a G, just as being called “Armstrong” does not entail having mighty biceps.164 Marc Lange formulates his analogous criticism in the following way: If [...] [the laws’] necessity arises merely ex officio from their lawhood, then praising the laws for their necessity would be as empty as praising the gods for loving the good, if being good is nothing more than being loved by the gods.165

Lange continues to argue that standard reductive necessitarian accounts on laws that treat lawhood prior to necessity cannot distinguish laws from non-laws by their necessity. On pain of circularity, necessity cannot be 161 162 163 164 165

See van Fraassen 1989, p. 96. See Lange 2009, p. 47. See Lange 2009, pp. 96- 97. See Lewis 1983, p. 366 Lange 2009, p. 47.

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what makes the laws the laws, if being necessary is entailed by their lawhood.166 Bas van Fraassen construes the inference and identification dilemma as being insoluble. He maintains that the key to solve the inference problem is extensional exclusion: Iff all instances of F are instances of G, then F is extensionally included in G. That way, the fact that F is extensionally included in G entails that every F is a G: inference problem solved. On the other hand, the identification problem is not yet solved, because if extensional inclusion were the relation we are looking for, then the account of laws of nature would be trivialised, as every universal quantification would then qualify as a law. So the relation must be something other than extensional inclusion. But if it is something else than extensional inclusion, the identification problem might be solved, but the inference problem remained open as it had still to be shown how something else than extensional inclusion could entail that every F is a G.167 Of course David Armstrong and Michael Tooley replied to the inference and identification problem as posed by van Fraassen. We will briefly discuss these replies, as they amply illustrate the metaphysical cost at which this kind of necessitarianism comes. We will then turn to the dispositionalist accounts. It has to be noted that Armstrong recognised the importance of van Fraassen’s dilemma and proposed elaborate answers to it. As for the identification problem, Armstrong at first admitted that it was insoluble in a way that would satisfy critics of the like of van Fraassen. He conceded that the necessitation relation, or rather the idea of one universal necessitating another has to be accepted as primitive.168 While this may seem unsatisfactory, it actually fits Armstrong’s view perfectly. What would it mean for the necessitation relation to be explained or further enlightened? It would have to be reducible to another, more intelligible relation. But one cannot simply demand that a particular relation be reducible to anther just to please an urge for explanation. If a relation is not reducible, and if there exists no independent case for it having to be reducible, then so be it. Armstrong’s immediate answer to his request for reduction of the necessitation relation 166 See Lange 2009, pp. 46-48. 167 See van Fraassen 1989, p. 97. 168 See Armstrong 1993, p. 412.

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is that there simply is not anything the necessitation relation should be reduced to. A couple of years and papers later Armstrong did in fact reduce the necessitation relation to causation and proclaimed the identification problem solved.169 Armstrong’s immediate response to the inference problem, as given in “What is a Law of Nature?” relates closely to his elaborate theory of universals. Armstrong’s first answer to the inference problem was the following: Remember that in Armstrong’s view a law of nature, the necessitationrelation that holds between a number of universals, is itself a universal of higher order that is instantiated in every state of affairs the necessitation-related universals are instantiated in. By this, Armstrong claims to have solved the inference problem. Suppose there is a law that all Fs are Gs: N(F,G). By his general theory of universals, N(F,G) is itself a universal of higher order, so it is instantiated in any state of affairs where a particular is an F and a G, in virtue of that particular’s being an F it is compelled by the relation between the universals F and G that is instantiated in it also to be a G.170 This solution, however, did not satisfy van Fraassen, who pointed out that while this special feature of Armstrong’s theory that the laws of nature not only relate universals but are universals themselves that are present in their instances actually does explain why, if it is a law that all Fs are Gs, any F is a G, but does not entail that all Fs are Gs. To repeat: according to van Fraassen, Armstrong’s laws can explain why some particular F is a G, but the universal conditional that all Fs are Gs is not entailed by the law and hence, Armstrong has not solved the inference problem.171 169 See Armstrong 19972, p. 507. 170 See Armstrong 1983, pp. 88-93. 171 See van Fraassen 1989, pp. 106 and 107. Apart from Armstrong not being able to answer the inference problem and identification problem, Van Fraassen claims that Armstrong falls into the trap of the lawgiver’s regress. We will not discuss the regress here, as it would only serve as an additional proof for the point I am trying to make in this essay: That necessitarian accounts of laws of nature come at a considerable metaphysical cost. For anyone interested in van Fraassen’s depiction of Armstrong’s and Tooley’s situation regarding the lawgiver’s regress, see van Fraassen 1989, pp. 99107.

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Armstrong responded to van Fraassen’s criticism and proposed a way out of this dilemma. Armstrong holds the view that both problems, the inference problem and the identification problem, can be solved simultaneously and thus objects to the problem’s status as a genuine dilemma.172 Armstrong purports that the necessitation relation can be identified if one follows the path of inferences that lead us (or the informed scientist) to postulate a particular law of nature N(F,G). At first, one directly observes a singular instantiation of the universal F causing a particular instantiation of G. Armstrong maintains that singular causation – not merely joint occurrence, but causation – is directly observable.173 From this instance of singular causation one may infer that there is a regularity instantiated in that instance of singular causation, maybe perhaps other instances of the same sort have been observed. This inference of course is inductive. From that, Armstrong continues, one may infer that what is common to all these Fs causing Gs is the instantiation of the universals F and G and that what accounts for the regularity of causation of Fs causing Gs is the fact that the universal F causes G, or in other words, that there is a relation between Universals F and G such that being an F causes being a G. Thus the peculiar relation N translates into nothing more than causation that holds between the higher-level entities that are the universals F and G.174 Having achieved this, Armstrong turns to the inference problem, which he claims to solve easily against the backdrop of his solution of the identification problem. He claims that once granted that the relation between the universals F and G is indeed the causal relation, the inference to the particular instances of F and G is easy: in fact, it is even analytical. Armstrong maintains that if there is a causal relation between the universals F and G how could it be possible that there is no according relation between a particular instance of F and a particular instance of G? 175 Predictably, van Fraassen is not satisfied with Armstrong’s solution to the inference and identification problem. Van Fraassen criticises Armstrong’s solution of the identification problem, because in his view, it is a 172 See Armstrong 1993, p. 421. 173 See Armstrong 19972, p. 501. 174 See Armstrong 1993, p. 421, and 19971, pp. 225-230. 175 See Armstrong 1993, p. 422.

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mere identification by postulate. Armstrong claims that the causal relation holding between tokens is epistemically primitive and part of our everyday perception of the world. That statement alone is bold in itself, but Armstrong further claims that the relation that holds between the tokens also holds between their types, the universals, is the very same relation. So as familiar as we should be with the causal relation holding between tokens according to Armstrong, as familiar should we be with causation in the realm of universals. And although van Fraassen concedes that there is no logical obstacle to construe the very same relation as holding between types and their instances respectively, the idea of a causal relation between universals is surely quite unusual. How should it be construed that a universal causes, necessarily brings about, another universal? Normally the relata of causal relations are construed as events, not universals – universals themselves that is, not particular instances of universals.176 Be that as it may be, van Fraassen, correctly, as I would like to suggest here, also rejects Armstrong’s solution to the inference problem. So while not to escape just one horn of the identification/inference dilemma would suffice for failure, Armstrong manages to hit both horns. Armstrong claims that by postulating that the necessitation relation that holds between universals is the very same relation that holds between their instances, namely the causal relation, the inference from the universals’ standing in a necessitation relation towards one another to the universally quantified conditional would be easy, analytic, in fact. But van Fraassen correctly claims that this inference is unjustified: for two types to be in a certain relation towards one another does not entail their instances being related in the same way: He [Armstrong] really loses me there: if a relation holds between two types, and is the sort of relation that can also hold between their tokens, it still does not follow that their tokens are indeed so related. Romeo and Juliet’s fathers hated each other but their children did not. [...] Universals bear many relations to each other which do not transfer to their instances – why does this one?177

176 See van Fraassen 1993, p. 436. 177 van Fraassen 1993, p. 436.

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Van Fraassen’s criticism certainly seems correct. While one even may accept the postulated solution of the identification problem, although an identification by postulate is not very convincing, the inference problem remains unsolved unless Armstrong gives us an independent reason why we should accept that the causal relation, in contrast to other relations, transfers from holding between universals to holding between their instances. Simply calling it “causal” and postulating that this trans-order transitivity is a necessary criterion for a relation to be causal does not do the trick, unless there are independent arguments for this. Michael Tooley has an answer of his own to the identification/inference dilemma. At first he tried to answer to the identification problem by what Theodore Sider called the stipulative solution.178 Having solved the identification problem, he then tried to take on the inference problem with what Tooley called his speculative theory.179 Tooley’s stipulative solution to the identification problem is simple. He merely lists all the properties that a solution that is worthy of the name “necessitation relation” must have and then stipulates that such a relation exists. Tooley tries to identify the necessitation-relation, which he calls relation K and which Theodore Sider calls “Tooley-relation”180 as follows: The relation of nomic necessitation is identical with the unique relation, K, which satisfies the following open formula: ‘For any property, universals P and Q, its being the case that P and Q stand in relation [to]181 R (1) logically entails its being the case that for all x, if x has property P, then x has property Q; (2) is not logically necessary; (3) is not logically equivalent to its being the case that certain facts about particulars obtain.’182

178 See Sider 1992, p. 262. 179 See Tooley 1987, p. 124. 180 See Sider 1992, p. 262. 181 I believe there is a typing error in the original edition and that “to” should be deleted, since R is the relation between P and Q, not something to which P and Q are related. 182 Tooley 1987, p. 80. Tooley offers an even more condensed version of this definition which we will not discuss because it would demand further elaboration.

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The stipulative solution as an answer to identification problem is not very convincing if taken in isolation. To answer a critic who demands the identification of the so-called necessitation relation that the relation has to have a certain number of properties and then simply stipulate its existence is just not very convincing. As a consequence, Tooley addressed the inference problem in isolation, hoping that further elucidating how the Tooleyrelation does its job would convince his critics that the stipulative solution is correct. Tooley, in contrast to Armstrong, is a Platonist regarding universals. This entails that in Tooley’s account, universals can exist even if not instantiated by any particular.183 Tooley also maintains that composite universals exist consisting of single universals such as the conjunctive universal F&G that consists of universals F and G. In the case of a universal law then, where every F is a G, F and G are parts of a composite universal and exist only as parts of that complex universal. In order to close the case on the inference problem, Tooley then claims that if a universal F is instantiated in a certain particular, and universal F bears a Tooley-relation to G, which yields the complex universal F&G, where F can only exist in the composite, then F&G must also be instantiated. Tooley asserts us that if F brings with it the instantiation of F&G and hence the instantiation of G, every thing that is an F is also a G. If this reasoning is valid the inference problem is solved. In Tooley’s own words: If it is a law that everything with property P has property Q, then the universal which is property P exists, in that world,184 only as part of the conjunctive property P and Q. Therefore, the only way property P can be instantiated in a given individual, in a world where that law obtains, is if the conjunctive universal is instantiated in that individual.185

Tooley himself does not seem to put much emphasis on the solution of the inference problem, as he mentions it and its solution only in passing and rests his case with that statement given above. 183 See Tooley 1977, p. 686. 184 The phrase “…in that world…” is meant to express Tooley’s constraint that laws of nature are contingent. 185 Tooley 1987, pp. 128-129.

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But unfortunately, the speculative theory arguably does little to illuminate the Tooley-relation, but contrarily rather further obfuscates an already obscure relation. Sider explicitly criticises Tooley’s application of mereology to transcendent universals. Siders’ criticism is strikingly simple and straightforward: Tooley cannot provide a satisfactory answer to the questions of how we should construe something consisting of parts and, more to the point, as existing only as a part of something else, given that it has only transcendent existence, and how that entails that everything which instantiates one part of the complex universal also instantiates the other part, without appeal to a further principle which warrants that consequence. This principle, according to Sider, would have to be a radical one, and hence highly speculative.186 A radical principle regarding the mereological nature of transcendent universals is a principle that goes well beyond uncontroversial principles such as transitivity of parthood: if a is a part of b, and b is a part of c, then a is a part of c. While transitivity is no radical principle, principles such as “every universal is a mereological atom” or the opposite “every universal has proper parts” are. Sider warns Tooley that any reference to a radical principle would make Tooley’s solution to the inference problem less plausible: These considerations prompt the following warning to Tooley: beware that you do not forfeit your claim to illuminate, lest you make no improvement on the solution by stipulation! We must be clear here about the goal of the speculative theory: The notion of a Tooley relation is initially mysterious. The speculative theory seeks to dispel some of that mystery. To make clear to us how there could be such a thing, the speculative theory must not introduce mysteries greater than the original. Appeal to radical principles would do just this.187

In the rest of his paper, Sider discusses a number of possible candidates for this further principle and rejects all of them. Sider admits that this is no thorough refutation of Tooley’s ontology, but that it depicts the problems this ontology is beset with.188 186 See Sider 1992, pp. 263-264. 187 Sider 1992, p. 264. 188 See Sider 1992, pp. 264-270.

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I will not go further into the discussion, but what I think can be seen clearly from the argument as it is portrayed above is that neither Tooley’s, nor Armstrong’s answers to the inference and identification problem will convince any critic who is already sceptical about the ambitious ontology involved. Remember that these problems lie at the heart of Tooley’s and Armstrong’s accounts. If they are not solved convincingly, all further problems that these accounts may have are not even worth addressing. I will leave the discussion open at this point. In order to be an Armstrongian or Tooleyan necessitarian, you have to accept their stipulative and even speculative answers, which is a considerable cost for the acceptance of these theories. Let us discuss if there are some ontologically less demanding accounts available.

2.1.2 BIRD Dispositionalists present a different type of necessitarianism. Most recently, dispositional analyses have become increasingly popular. Some of the most prominent contemporary philosophers advocating such a view are Brian Ellis, Alexander Bird, Stephen Mumford, and Nancy Cartwright.189 In general, dispositional theories of laws of nature can be quite similar to the Armstrong-Tooley-Dretske-view, with the sole difference that in Armstrong’s view a law of nature is a relation between categorical properties, i.e. properties that are manifest at all times, whereas in dispositionalist accounts the relata are dispositions, i.e. properties that are manifest only given that certain manifestation conditions are fulfilled. These views of laws of nature share a good deal of problems with the classical ArmstrongTooley-Dretske-account of laws of nature. We have seen above that these takes on natural laws are afflicted by the inference and the identification problem, which according to Hüttemann also apply to these dispositionalist contingent necessitation accounts.190 Just by changing the relata of natural laws the identification and inference problem does not go away; it still has to be shown how exactly contingent natural necessitation can actually force 189 See e.g. Ellis 2001 and 2002, Mumford 2004, Bird 2005 and 2007, Cartwright 1989, Bartels 2000, and Hüttemann 20071 and 20072. 190 See Hüttemann 20072, p. 152.

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the manifestation of the dispositional property given that the manifestation conditions are met. Accordingly, our criticism of the ADT-view largely also applies here, so we do not have to give a detailed overview over these theories. However, Alexander Bird and his allies introduced a novel aspect to his theory of laws of nature, which consequently we will have to look at in a bit more detail: Bird claims that the laws of nature are entailed by the fundamental physical properties’ dispositional character.191 If for example all particulars that share a certain property are water-soluble,192 then it is a law of nature that they have to dissolve when placed in water under the right circumstances. This line of thought is very different from David Armstrong’s. Alexander Bird criticises Armstrong for his take on nomological necessity, which Armstrong takes to be a relation between instances of universals, which is contingent in the sense that there are possible worlds in which different laws of nature hold. Bird claims that he cannot make sense of this middle-way contingent necessity, whereas his necessity is more straightforward because it is entailed by the proposed fact that all fundamental properties have the same dispositional character in every possible world that shares the same properties.193 Bird thus claims to escape van Fraassen's inference and identification problem because he can show why certain properties always produce certain results by stating that it belongs to their essence to have these particular causal effects and he can show what it is that necessitates Fs to be Gs: their essence to produce Gs, which is the same in every possible world.194 Thus, in contrast to Armstrong, Tooley and Dretske, Bird takes nomological necessity not as contingent necessity, i.e. necessity that holds in our world and not in all possible worlds, but as Necessity with a capital “N”. For Armstrong, Tooley, and Dretske, for a state of affairs to be necessary it has to be necessitated by a law of nature, but that law of nature could well have been different. In Bird’s view, however, if a state of affairs holds necessarily it holds in all metaphysically possible worlds which share the same relevant properties as 191 See Bird 2007, p. 46. 192 Being water-soluble is probably no fundamental property, but as it is such a prominent example of a dispositional property, I will use it for illustration purposes. 193 See e.g. Bird 2007, p. 44 and Bird 2005, p. 355. 194 See Bird 2005, p. 355.

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ours. Thus the laws of nature are essential – necessary – features of any world which has the same relevant properties. We will turn to his reasons for this view further below. Let us discuss Bird’s theory in a bit more detail: Bird holds that all fundamental properties possess dispositional character as their essence. This view is expressed in Bird’s principle (DM): (DM) All sparse, fundamental properties have dispositional 195 essences. To give an example, being soluble in water is a dispositional property, as it designates an effect that will become manifest, given that certain conditions such as putting the particular in question in (e.g. not oversaturated) water were fulfilled. The particular in question thus can have a property that does not have to be manifest at all times to have that property. For a thing to be water-soluble it does not have to be actually dissolved, it might not even be dissolved at all at some time in its history and still be watersoluble. Bird offers a way of formalising the dispositional character of a certain property in the form of a conditional analysis (CA). Let D(S,M)) stand for “x is disposed to manifest M in response to S”, where S stands for the stimulus property, i.e. the property that makes the dispositional property M manifest: (CA)

D(S,M)x↔Sx□→Mx

Because Bird is a dispositional essentialist who holds that not only does a stimulus necessarily make the dispositional property manifest, but also that it does so in every possible world with the same fundamental properties, (CA)□ holds: (CA)□

□(D(S,M)x↔Sx□→Mx)196

195 See Bird 2007, p. 45. Bird in fact endorses not only (DM), but (SDM), which is the stronger claim that fundamental properties do not only have dispositional essences, they have no essences but dispositional essences (See Bird 2007, p. 72). 196 Bird 2007, p. 43. Here and in the following quotations from Bird 2005 and 2007, I adapted the italics to match my standard as described above.

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Thus, necessarily, a particular has a certain disposition if and only if, if the stimulus property occurred, the manifestation property would hold. Translated in layman’s terms, it is necessarily the case that a cube of sugar is water-soluble if and only if, were it to be put into water, it would dissolve. The conditional analysis (CA) entails that ∀x((Dx∧Sx)➝Mx).197 Whether or not dispositions can be analysed in this way is subject to an extensive debate. Bird confesses that strictly speaking, (CA) is not true for all cases. A lot of times, e.g. in the cases of finks or antidotes, the instantiation of a disposition and the instantiation of the stimulus together fail to entail the manifestation of the disposition, rendering (CA) false.198 But the falsity of (CA) does not entail the falsity of the dispositionalist theory of laws of nature. Bird claims that there are different sorts of laws: those which satisfy (CA) and are universal in the third sense given above, i.e. that they hold under any circumstances, and those which do not satisfy (CA): the cp-laws. Bird claims that in those cases where the conditional analysis fails, this failure can indeed serve to discover and fully understand the finks or antidotes present.199 Bird holds that all properties are to be identified by their dispositional character, even the ones that do not seem to be dispositional at first glance and normally are regarded as archetypes of categorical properties such as having a certain mass for example. But Bird points out that what identifies having a mass of 10.2 kilograms for example are the causal effects this property could produce if put in the right conditions and which are unique to that property.200 Moreover, and more importantly, Bird also is, as we 197 See Bird 2005, p. 355. 198 This may be the case with finkish dispositions or dispositions for which there exist an antidote. A finkish disposition is a disposition which changes whenever the stimulus occurs such that it fails to become manifest. Bird gives an example of a substance that has the disposition to brittle when struck if the substance is cold, but where the striking of the substance that according to the disposition should cause the substance to brittle heats the substance such that it loses the disposition of being fragile when struck. While a finkish disposition forecloses its own manifestation, an antidote is an external factor that gets in the way of a disposition’s becoming manifest, much like a normal antidote would get in the way of a poison that has the disposition to kill a person if ingested (See Bird 2005, pp. 357-359). 199 See Bird 2005, pp. 359-360. 200 See Bird 2007, p. 45 an chapters 4 (pp. 66-98) and 7 (pp. 147-168).

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have mentioned above, an essentialist. He claims that not only are all properties identified by their dispositional character, they also have the same dispositional character in all possible worlds. There is no possible world out there where the property “to have a mass of 10.2 kilograms” comes with a different dispositional character and produces different causal effects than in our world. Thus, we get principle (DEp), where P denotes a potency: (DEp)

□(Px⊃D(S,M)x)201

Which reads: “In all possible worlds, any object that possesses P is disposed to yield M in response to S. From (DEp) and (CA)□, Bird arrives at his definition of laws of nature, which not only solves the inference problem, but in essence to any obscure necessitation relation N also the identification problem, as there is simply nothing to be identified. So (DEp) and (CA)□ yields: (I)

□(Px⊃(Sx□→Mx)),202

from which, in a couple of simple mutations and from the assumption that x is arbitrary we finally get (V)

∀x((Px∧Sx)⊃Mx).203

As (V) holds in any possible world, we finally get (V□), which is Alexander Bird’s analysis of laws of nature: (V□)

□∀x((Px∧Sx)⊃Mx).204

Thus, the inference problem is solved – given that dispositional essentialism can be independently supported. As mentioned above, in dispositional essentialism the identification problem need not be solved, but simply dissolves, as there is no peculiar relation such as the Tooley Relation or Armstrong’s necessitation relation to be identified. 201 202 203 204

See Bird 2007, p. 45. See ibid. See Bird 2007, p. 46. See Bird 2007, p. 48.

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So why not buy into this, then? While Bird’s account is beautifully designed and argued for, it is metaphysically very ambitious. We have seen above that Bird’s view of laws of nature is embedded in, and indeed dependent on, his monistic dispositional essentialism, the view that every fundamental property is a potency, i.e. a property that is identified by its dispositional character, and every property has the same dispositional character in all possible worlds. Hence, in Bird’s theory, it is metaphysically, not just nomologically, impossible for an ice cube not to dissolve when placed in water under the right conditions. He develops this view along considerations of transworld identity, the question of what it is that makes a certain object, or a certain property, the same in one world and in another. If a particular or a property has one aspect to it in each and every possible world, then this aspect is called an essence. Bird develops his own view against the backdrop of a thorough critique of quidditism, which is the claim that a property’s trans-world identity is fixed by a primitive nonqualitative aspect, a quidditas.205 Quidditism is to properties what haecceitism is to particulars. Bird defines quidditism as follows: (QA1) For all fundamental universals F and powers X there is a world where F lacks X.206 This definition of quidditism also allows for the following two refinements, which, according to Bird, are entailed by (QA1): (QA2) For any world w1, any fundamental universal F, and any power X, where at w1, universal F has X, there is a world w2 like w1 in all fundamental respects except that the very same universal F lacks X. (QA3) For any world w1, any fundamental universal F, and any power X, where at w1, universal F lacks X, there is a world w2 like w1 in all fundamental respects except (i) that very same universal F possesses X, and (ii) F does not possess any powers inconsistent with X.207

205 The term “aspect” is used here to express neutrality with regard to whether the quidditas is a second-order property. 206Bird 2007, p. 71. 207 Bird 2007, pp. 71-72, my italics.

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From (QA1) via (QA2) and (QA3) Bird derives (QB1): (QB1): Two distinct worlds, w3 and w4, may be alike in all respects except that: (i) at w3, universal F has powers {C1, C2,…}; (ii) at w4, universal G has powers {C1, C2,…}; (iii) F≠G.208 Dispositional monism of the sort Bird proposes is incompatible with (QA1) – If (QA1) is true, dispositional monism cannot be. Note that Bird distinguishes between dispositional monism (DM), which is incompatible with (QA1)-(QA3), and strong dispositional monism (SDM), which in contrast to (DM), is not entailed by the denial of (QA1). Strong dispositional monism, the view that Bird endorses, is the claim that every fundamental property not only has a dispositional essence, but indeed consists of its dispositional essence, of its causal powers. If (DM) was true, it could on principle be the case that fundamental properties have a dispositional essence and in addition to that also have a quiddity. This possibility is ruled out by strong dispositional monism (SDM). Although (SDM) is, according to Bird, not entailed by the negation of (QA1), it is not compatible with (QB1). In fact, Bird announces that (SDM is in fact (DM) plus the negation of (QB1). Hence, Bird, who endorses (SDM), needs two arguments: one against (QA1) to establish (DM) and one against (QB1) to come from (DM) to (SDM).209 However, since (DM) is incompatible with (QA1-3), if Bird’s arguments against (QA1-3) fail, (DM) falls and ultimately, so does (SDM). Bird’s argument against (QA1) is a classical slippery slope role-swapping argument similar to Roderick Chisholm’s classical arguments against haecceitism.210 If (QA1) - (QA3) were true, then it would be possible to imagine a series of worlds where two fundamental properties step by step swap their causal powers. If we are still talking about the same property, then this property must have a quidditas, something over and above its causal roles that makes that property that property. Mumford describes the question as follows:

208 Bird 2007, p. 72, my italics. 209 See Bird 2007, pp. 72-73. 210 For Chisholm’s original argument, see Chisholm 1967.

79 The telling question these cases produce is how, if the causal role of a property is altered, are we still talking of the same property? If something has the causal role of F, why are we not now talking of F? And if F now has the causal role that G had, why is F not G? The only available answer seems to be: if the property had a quiddity over and above its causal role. But this allows that F and G could swap their entire causal roles and yet still be the same properties they were.211

Bird’s example is mass and charge: consider all causal powers mass and charge have in our world, and then conceive of a series of possible worlds in each of which mass and charge exchange one of their original causal powers they possess in our world, until we arrive at a possible world where mass has all the causal powers that charge has in our world and vice versa. The way to argue against (QA1) - (QA3) is to show that these worlds are not genuinely possible.212 Unfortunately, Bird does not give us conclusive reasons to think that they are not possible apart from our intuitions that supposedly tell us that a world where mass behaves as charge in our world and charge behaves as mass in our world is absurd, as are all the intermediate worlds. Bird’s argument against (QB1) is a little different as it does not rest on intuitions as much, but rather tries to highlight the sceptical consequences of (QB1). Bird concludes that through various iterations of property-swapping allowed in (QB1) we yield (QB2): (QB2): One and the same world w is such that: (i) at w, universal F has powers {C1, C2,…}; (ii) at w, universal G has powers {C1, C2,…}; (iii) F≠G.213 Instead of applying to different worlds as (QB1) does, (QB2) applies to one and the very same world. Note that Bird does not claim that (QB2) is a direct logical consequence of (QB1), Bird merely concludes that (QB2) is “implied in the quidditist picture”.214 The problem with (QB2) is now that there may be a lot of properties with the same causal profile which yet still 211 212 213 214

Mumford 2004, p. 104, my italics. See Bird 2007, p. 75. Bird 2007, p. 76, my italics. See Bird 2007, p. 76.

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may not be identical, which leaves us with the problem that we may never know which of these fundamental properties is actually instantiated, as all of these properties share the same causal profile.215 We will not follow the discussion any further, as we have already seen that his argument against (QA1-3) is questionable, and while the negation of (QA1-3) does not entail (SDM), (QA1-3) does entail (SDM)’s negation. But quidditism is not without contemporary defenders. Let me briefly sketch one of the most potent defences of quidditism. Jonathan Schaffer argues for what he calls quiddistic contingentism, which is the view that the relations between the properties and the causal role they play are contingent. That is to say that there are possible worlds in which like charges attract. Thus, according to quiddistic contingentism it is even possible that properties switch their entire causal profile, resp. switch their quidditas. The various necessitarian and contingentist views differ in the range of possible worlds they countenance. To a necessitarian regarding the causal profiles of properties such as Bird, a world in which like charges attract is not metaphysically possible, whereas it is for a quidditist. An anti-quiddistic contingentist holds that properties cannot change their causal profile entirely, because they are world-bound.216 Schaffer argues that contingentism is necessary for our usual modal counterfactual reasoning. In some contexts, it is useful to say that like charges might attract, given that certain conditions occur. Likewise, for counterfactual reasoning, it is often necessary to assume a small miracle, which could only be brought about by a small violation of the laws or of the causal roles of some properties.217 These two arguments are similar to an argument given by Robin Hendry and Darrell Rowbottom which we will discuss below. Schaffer also holds that contingentism is necessary for our standard way of thinking about propositions, conceivability and recombination.218 For the sake of brevity, let us consider only the argument from conceivability: If it is impossible that 215 See Bird 2007, pp. 77-79. 216 See Schaffer 2005, pp. 4-5. 217 See Schaffer 2005, p. 8. 218 “Recombination” here means the possibility of free reallocation of the zoo of entities between possible worlds. Consider two entities, x and y. There are possible worlds in which only x exists, such in which only y exists, and such in which both exist (see Schaffer 2005, p. 9).

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like charges attract, then this should be inconceivable. But it is conceivable, hence it is not necessary that like charges attract.219 Schaffer goes on to argue for quiddistic rather than anti-quiddistic contingentism, which latter holds that properties are world-bound and hence does not allow transworld identity of properties. Schaffer holds that almost all theories of properties allow for transworld identity, and that any view arguing against the transworld repeatability of properties should provide us with good reasons to accept such a view. Schaffer argues that there are no such good reasons.220 Let us take stock: in a first step of his argument for quiddistic contingentism Schaffer argued for contingentism, regardless of whether quiddistic or not. In the second part of the argument he argued for the possibility for transworld identity of properties, which together with his argument for contingentism establishes quiddistic contingentism. But Bird gives another argument against quidditism along the following lines: If quidditism was true, then it would, as we have seen, be possible that there are functionally equivalent but categorically distinct properties. If this was the case, we could not be certain whether our theoretical terms refer to the properties they are taken to refer to, because it would be possible that the functional role of a property could be multiply realised. That is to say that we could never be certain whether our theoretical terms refer to a particular property or to a functionally equivalent but categorically different property. Bird holds that we should not accept this sceptical consequence of quidditism. He holds that we should not be condemned to scepticism by the choice of our metaphysical theories.221 Schaffer’s reaction to this argument is that this scepticism is no different from any other possible world scepticism or scepticism about the external world. In fact he holds that it is a subspecies of scepticism about the external world, since it is a scepticism about the quiddistic aspect of the external world. The way 219 See Schaffer 2005, p. 10. The soundness of this argument obviously hinges on the impossibility of a Kripkean reply of the sort that the alleged conceivability stems from a misdescription, i.e. that, if we are saying that we can imagine that like charges attract, we are only speaking of like schmarges which schmattract. Schaffer discusses the Kripkean response at length (see Schaffer 2005, pp. 10-12). 220 See Schaffer 2005, pp. 13-14. 221 See Bird 2007, pp. 77-79.

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to react to sceptical arguments, Schaffer holds, is not to give in and infer from them to the falsity of the theory which sparked them, but to show how our theories of knowledge can solve these sceptical arguments.222 We could go on here for a very long time and list argument after counter-argument after argument for and against quidditism,223 but let us focus on the issue at hand. Bird claims that his theory of laws of nature, which is motivated by his essentialist dispositionalism, is better off than the other theories on the market. So let us investigate whether it does not have problems of its own. If that is the case, we should seriously consider whether it is worth the metaphysical cost at which it comes. There is an unease with this kind of reasoning which is parallel to Sider’s argument against Tooley’s solution to the inference argument. That unease is that the solutions to notorious problems should not be mysterious themselves. We should not counter problems we encounter in theories of properties by proposing such radical theories as essentialism. My unease at this kind of reasoning is analogous to David Hume’s discomfort with occasionalism: Though the chain of arguments which conduct to it [occasionalism] were ever so logical, there must arise a strong suspicion, if not an absolute assurance, that it has carried us quite beyond the reach of our faculties, when it leads to conclusions so extraordinary, and so remote from common life and experience. We are got into fairy land, long ere we have reached the last steps of our theory; and there we have no reason to trust our common methods of argument, or to think that our usual analogies and probabilities have any authority. Our line is too short to fathom such immense abysses.224

However, unease with an abundant ontology is no conclusive argument against a philosophical position. Rather, let us see whether the theory of laws of nature which is motivated by Bird’s dispositional essentialism proves to be successful. We will consider two objections against disposi-

222 See Schaffer 2005, pp. 16-20. 223 See e.g. Schaffer 2005, p. 19 and Bird 2007, pp. 77-79 for the details of the debate between these two authors. 224 Hume: Enquiry, section 7, part 1.

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tional essentialist conceptions of laws: First we will consider an argument by Robin Hendry and Darrell Rowbottom, then we will turn to an argument given by Markus Schrenk.225 Hendry and Rowbottom argue for a more admissive version of dispositional essentialism that would allow for some laws to be contingent. Why is this argument interesting for our overview of theories of natural laws? Because if (some of) the laws turn out to be contingently true in the dispositional essentialist picture, then the inference and identification problem strikes again. So let us discuss Hendry’s and Rowbottom’s argument. They do not challenge the essentialists’ criticism of quidditism, which is, as we have seen, one of the cornerstones of the argument for dispositional essentialism. Hendry and Rowbottom do, however, argue that what they call “nomic necessitarianism”, the doctrine that the laws of nature hold in all possible worlds, is not entailed by the denial of quidditism.226 The problem with dispositional essentialism is that it completely prohibits counterlegals that refer to some properties having slightly different causal roles than they have in our world. Such counterlegals are, as we will see, sometimes very useful in scientific analyses. Hendry and Rowbottom search for a middle ground between quidditism and dispositional essentialism so that certain counterlegals that are in widespread use in actual scientific practice could still be true. Hendry and Rowbottom use the boiling point of water as an example. We can ask what specific physical features of H2O lead to its compared to other hydrides unusually high boiling point. One usual way of explaining water’s unusually high boiling point is to counterlegally suppose how high the boiling point would have been, had H2O been bonded together with van der Waals force instead of via hydrogen bonding, marking out hydrogen bonding as the relevant factor that accounts for the

225 Another major complaint about dispositional essentialist conceptions of laws voiced by Marc Lange will be ignored here, as it required quite a lot space to be discussed properly. In short, Marc Lange argues that dispositional essentialism cannot account for the laws supporting counterfactuals and the laws holding under any counterfactual supposition that is logically consistent with the laws unless augmented by an extra principle (See Lange 2004). 226 See Hendry and Rowbottom 2009, pp. 669-670.

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unusually high boiling point of water. Such an explanation, however, is not available for the orthodox dispositional essentialist, as he could not state the truth conditions of such counterlegals.227 Hence, Hendry and Rowbottom plead for a middle ground between dispositional essentialism and quidditism: a dispositional essentialism that allows only for certain causal powers of a property to be contingent, which yields a position they call “dispositional contextualism”.228 They spell out their theory in the following terms: while they agree with Bird that the transworld identity of dispositional properties is fixed by their causal essences, Hendry and Rowbottom allow not only for actual dispositional essences, but also for merely possible ones. So a property’s identity is fixed by the dispositions it has, but apart from the actual dispositions, it has possible dispositions which bring certain manifestations about only in certain possible worlds. Thus a property can cause a different manifestation in one world than in another world.229 However, this move does not allow for quiddities to fix the identities of properties as one might think. The trick is that one property is not characterised by one set of dispositions it has in one world and characterised by a different set of dispositions in another. If that was true, then dispositional contextualism would require quiddities to fix transworld identity. According to dispositional contextualism, one property has the same set of dispositions in any possible world, but from world to world it may vary which of these dispositions are actual and which merely possible. The possible and actual dispositional profiles a property might show in different possible worlds have to stand in an appropriate similarity relation R to one another. 230 Let us assess Hendry’s and Rowbottom's proposal: One of the most obvious objections to that account is that if a property does exhibit a slightly different dispositional profile in different possible worlds, we are actually dealing with different properties. Hendry and Rowbottom respond to this criticism by stating that the only way to back this claim would be to show that the laws of nature are (metaphysically) necessary, which would 227 228 229 230

See Hendry and Rowbottom 2009, pp. 670-672. See Hendry and Rowbottom 2009, p. 672. See Hendry and Rowbottom 2009, p. 674. See Hendry and Rowbottom 2009, p. 674.

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be question-begging as the law’s necessity is taken to be entailed by dispositional essentialism.231 One might also refer to our modal intuitions and claim that by admitting that one and the same property can have different actual dispositional profiles in different possible worlds, one could also change the entire dispositional profile of a property piecemeal. Eventually, even causal role-swapping scenarios by changing the dispositional role of properties piecemeal would ensue. The modal intuitions involved are exactly the same that put the dispositional essentialists off quidditism. Hendry and Rowbottom respond to this regress argument by introducing a similarity relation R which can help us identify those properties which are still similar enough and those that are not. That similarity relation, however, remains critically underdetermined by the two authors: all we learn is that it is taken to be intransitive in order to block piecemeal causal roleswapping, but that is about it.232 So in the end the introduction of R seems ad hoc and and the relation itself underdetermined. As yet, Hendry’s and Rowbottom’s account is merely a sketch, so it is difficult to assess its potential. If they fail to further clarify and defend their account, there would be no way of introducing counterlegals in a dispositional essentialist picture. But since counterlegals are stock-in-trade tools of actual scientific practice, we need truth conditions for them. Bird insists that while our modal intuitions might push us towards accepting counterlegals, we should not rely on our intuitions. But Hendry and Rowbottom are quite right in stating that we then neither have any reason to follow Bird’s argument against quidditism, which was based on his modal intuitions in the first place.233 However, if the two authors turn out to be right and are able to spell out R, then we might end up with at least some of the laws being contingent, leading to the exposure to the inference and identification problem all the contingent necessitation views of laws of nature face.

Another more specific complaint than my rather vague discomfort with abundant metaphysics is a worry expressed by Markus Schrenk, who argues that while metaphysical necessity might do the job of connecting 231 See Hendry and Rowbottom 2009, p. 674. 232 See Hendry and Rowbottom 2009, p. 675. 233 See Hendry and Rowbottom 2009, p. 672.

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synchronic properties, it cannot connect diachronic instantiations of properties – it cannot bind events together in the way we demand from the necessitarian’s laws. In the new essentialists’ view, the stimulus brings about the effect with metaphysical necessity.234 Schrenk’s main argument for this claim is that whenever a causal process is stretched over time, whenever the cause is temporally prior to the effect, then it is at least on principle possible that the effect could be prevented. If that is the case, Schrenk argues, then the cause cannot bring about the effect with metaphysical necessity. Schrenk argues that if it is possible that the cause does not produce the effect, then the occurrence of the effect after the occurrence of the cause cannot be necessary because, by definition, if an event is necessary it cannot possibly not occur, given that the stimulus occurred.235 We will not go into detail here, but let us focus on Schrenk’s two main arguments to fully grasp the oddity of the claim that it is metaphysical necessity that links causes and effects and hence accounts for the necessity of natural laws. The two arguments Schrenk discusses rest upon two properties of metaphysical necessity: monotonicity and discreteness. The necessary connection is monotonic in the sense that if there is a necessary connection between events of type C and their effects, events of type E, this necessity should also hold in cases where a C is conjoined with another event A. Schrenk holds that metaphysical necessity is by definition monotonic – it holds no matter what. But if event A is a successful antidote, i.e. an event that prevents the effect E from occurring after it has been triggered, obviously the connection between C and E could not have been metaphysical necessity, as that would have been monotonic and would have brought about E no matter what, even if A occurred.236 If the dispositional essentialist wants to solve that problem she runs into the second problem. The obvious response to the monotonicity problem would be to state that not C is the correct relatum, but C with the addendum that any interfering factor is absent. The problem now is that metaphysical necessity is thought to be discrete, which means that it does not allow for a continuum of weaker causes and weaker effects. If C and E 234 See Bird 2007, p. 64, Ellis 2002, p. 110, and 2001, p. 286, cited after Schrenk 2010. 235 See Schrenk 2010, p. 730. 236 See Schrenk 2010, pp. 731-732.

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are related by metaphysical necessity, an impure C cannot lead to just a little bit E. The connection holds only between pure Cs and pure Es. Schrenk illustrates this point with the example of radioactive decay: suppose that a lump of uranium beyond its critical mass is disposed to chainreact. If boron rods are inserted into the uranium heap, they prevent the chain reaction. But if you pull them out gradually, there will be more and more free electrons, just until the boron rods cannot prevent the chain-reaction anymore. Since metaphysical necessity is discrete, it can account for the pure cases, i.e. for the cases where there is no interfering factor, no boron rods in our case, and where the interfering factors are completely present: in Schrenk’s example the boron rods are fully inserted. But it cannot account for all the cases in between, where the gradual decrease of boron leads to the gradual increase of free electrons. But laws of nature should be able to explain these cases, which is exactly what laws which require that all possible interfering factors are absent cannot.237 So this is the problem: either the essentialists admit the possibility of antidotes which prove that the connection between cause and effect cannot be metaphysical necessity, or they try to explain the antidote cases away, but then the problem of discreteness arises which prevents the explanation of intermediate states. But we would like to be able to give an explanation of these intermediate states. Remember that according to Hüttemann, laws play an important role in explanation and prediction.238 If Schrenk’s dilemma succeeds, either the dispositional essentialists have to admit that their laws cannot fulfil that role in all relevant cases, or they have to admit that the necessity involved is not metaphysical necessity. But in this case they are again faced with the inference and identification problem.

Let us sum up. In 2.1.1 we have seen that necessitarian theories of laws of nature that focus on universals are problem-laden and metaphysically quite expensive. We have seen that neither Tooley, nor Armstrong are able to satisfactorily solve the inference and identification dilemma. When we turn to dispositional accounts, we find that either they share the same 237 See Schrenk 2010, pp. 732-733. 238 See Hüttemann 20072, p. 141.

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problems as Armstrong, Tooley and Dretske, or, as it is the case with the new essentialists, have to reach even further into deep metaphysics. Dispositional essentialism, apart from breaching ontological austerity, has its own share of problems. As we have seen, dispositional essentialism cannot quite account for its claim that it is metaphysical necessity that compels nature to behave as it does. Moreover, maybe it even has no solution to the question of how to support counterlegals. Remember that one of the main motivations for the dispositional theories was to solve all the problems the Humeans have, but at the price of a more extensive metaphysics. But it seems that this more extensive metaphysics produces some problems of its own. But let us take a step back here. The whole programme of necessitarianism is driven by the urge to overcome Humeanism. Humeanism is, as we will see below, perceived by the necessitarians as being scourged with problems and not even being able to preserve our most basic intuitions, for example to the question how to distinguish accidental regularities from “real” laws. The necessitarians buy their solutions to these problems with abundant metaphysics. But is Humeanism really so badly off that we have to replace it? If it turns out that Humeans of some shape or form are able to answer the challenges posed to them by the necessitarians, why should we buy into the ontologically dissipative accounts? Let us for a moment recapitulate our situation. We have seen in chapter 1 that strong determinism is in need of necessity with a vengeance, a compelling force. The necessitarians could provide determinism with such a force, be it Armstrong’s necessitation relation or Bird’s metaphysical necessity that holds between spatiotemporal distinct events. By now it should be more than a sneaking suspicion that Humeanism cannot – and is specifically designed not to – provide such a compelling force in nature. But if Humeanism of some form is tenable and hence able to support Humean determinism, then we can evaluate what that entails for the standard arguments against libertarian free will. So let us investigate how Humeanism fares.

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2.2 BROADLY HUMEAN ACCOUNTS Humeanism differs from the necessitarian views sketched above in the respect that it denies any necessary connections between states of affairs, properties, etc. in nature. All recent Humean accounts on laws of nature, causation or ontology in general share the same basic ontological conviction that there are no modal forces in nature. In such a view, everything there is, and that includes laws of nature, supervenes on the basic facts and is not allowed to contain any modal force that compels nature to behave in a certain way as in Armstrong’s or Bird’s view. So any Humean proposes at least some form of Humean supervenience. John Earman and John Roberts give following definition of Humean supervenience applied to laws of nature: HS: What is, and what isn’t, a law of nature supervenes on the Humean base of facts.239

However, Humeans dissent over the question what the subvenient base consists of, i.e. what the basic ontological units are that our world is made up of. All the Humeans who might propose different accounts of what the Humean base consists of do however unanimously agree that nomic facts do not belong to the Humean base. David Lewis, who famously coined the phrase “Humean supervenience”, defined the Humean base as the spatiotemporal distribution of local qualities.240 This commits Lewis to deny any non-local qualities, which is at odds with our current best scientific theories.241 As we have seen in chapter 1.3.1, quantum theory in both of the most influential versions is non-local because both the Copenhagen theory as well Bohmian approaches allow quantum-entanglement, which is a nonlocal phenomenon. Thus, to defend a Lewisian subvenient base entails the

239 Earman & Roberts 2005, p. 7. 240 See Lewis e.g. 1994, p. 474. 241 See Earman and Roberts, 2005, p. 8.

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claim that at least one branch of current physics is wrong about locality – a claim that after the work of John Bell and Alain Aspect is a very bold one for any philosopher to make.242 Since some sort of Humean supervenience is part of each and every Humean account of laws of nature, we have to look at a series of counterexamples and criticism raised against it and assess whether Humean supervenience is defendable. If no sort of Humean supervenience succeeds to be defendable, all of the Humean accounts on laws of nature fail, including the orthodox regularity theory as well as best system analyses; so any defence had better be good. The most common kind of criticism levelled at Humean supervenience of any sort are thought experiments that allude to our intuitions about natural laws. Various counterexamples have been designed which all try to make the same point: that it is possible to conceive of a set of possible worlds which share the same Humean base but which differ in their laws. Let us discuss the two most prominent of these thought experiments. Michael Tooley asks us to conceive of a world that contains 10 types of elementary particles. The only interaction in this world are collisions between these particles. A host of ten different types of particles allows for 55 different kinds of collisions between them. But, and this is the twist in this argument, the 55th kind of collision between X-particles and Yparticles, as Tooley calls the uncooperative types of particles, never in the history of that universe ever happens. Collisions between these types of particles are not prohibited by any natural law, it just so happens due to the boundary conditions of that universe that this collision never occurs. So Tooley argues that as there is no law ever instantiated which governs the collision of X-particles and Y-particles, a supposedly infinite host of uninstantiated laws governing this evasive collision is possible. So according to Tooley, there are many, if not infinitely many, possible worlds with the 242 See e.g. Aspect et al. 1982. Tim Maudlin also argues against a Lewisian view of Humean supervenience because it presupposes locality, which is at odds with quantum theory (See Maudlin 2007, pp. 53-61). The other arguments against Humean supervenience that Maudlin invokes are that Humeanism cannot give an account of counterfactuals, chance, and physical possibility and necessity (see Maudlin 2007, pp. 64-68). These worries will not be discussed here because they can be addressed very differently within the scope of the various actual Humean theories of laws of nature.

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same Humean base which differ in respect to the one law that governs the collision between X-particles and Y-particles. This is a counterexample to Humean supervenience, because according to Humean supervenience it should not be possible that there be a difference in laws without a difference in the Humean base.243 John Carroll provides a similar counterexample. Carroll asks us to conceive of a total of four different worlds, U1, U2, U1*, and U2*.244 Suppose in world U1 there are X-particles and Y-fields. Every time an X-particle enters a Y-field in U1, it has spin up. Thus, it is a law in U1 that every X-particle in a Y-field has spin up. Carroll calls this law L1. In world U2, on the other hand, every X-particle behaves exactly as X-particles are supposed to behave in U1, but there is one single X-particle which goes by the illustrious name “b” which has spin down in a Y-field. Hence, L1 cannot be a law in U2. Both worlds also feature a mirror that is capable of reflecting Xparticles that is in position c, which allows b to fly past it into the nearest Y-field. The mirror is suspended from a well-greased hinge and thus can easily rotate so that in can block b’s way into the Y-field if rotated. Also, the basic laws of particle motion are the same in all the possible worlds at hand. So far, this does not serve as a counterexample to Humean supervenience. But now Carroll asks us to imagine a minor change to either U1 and U2, namely to slightly change the position of the mirror to position d in both worlds such that the stubborn particle b never enters the Y-field. Carroll calls the resulting worlds U1* and U2*. Now the defender of Humean supervenience faces a problem. In U1*, L1 holds as well as it does in U1. But in U2*, things are not as easy. In U2*, particle b never enters the Yfield, so the worlds U1* and U2* share the same Humean base, yet have a different set of laws, as according to Carroll, law L1 does not hold in U2*. Carroll comes to the conclusion that L1 does not hold in U2* as it is no law in U2 and a slight change such as the mirror’s position cannot account for a change in natural laws.245 So, to sum up, Carroll tries to construct a counterexample to Humean supervenience by envisaging two possible 243 See Tooley 1977, p. 669. 244 In order not to depart too far from Carroll’s notation, I will not set the possible worlds in this section in italicised small print letters, as would be in accord with the standard notation of this text. 245 See Carroll 1994, pp. 60-61.

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worlds with the same subvenient Humean base but a different set of laws, which, according to the defenders of Humean supervenience, is plainly impossible. Ultimately, the counterexample comes as a dilemma. The defender of Humean supervenience would either have to accept that L1 is a law in U2*, which would lead to the supposedly implausible conclusion that the position of a mirror can change the laws, or, as the second horn of the dilemma, they would have to hold the laws in U2 and U2* constant in order to avoid a change in laws by a repositioning of a mirror, but then the Humean base in U1* and U2* is identical, yet the laws are different, because L1 is a law in U1*, but not in U2*.246 While this counterexample strikes many as intuitively plausible, Carroll gives a more sophisticated formal version of it, which, as we will see, makes it quite a bit clearer for a defender of Humean supervenience to see where to attack it compared to the intuitive version given above. For this formal argument, Carroll introduces a modal principle, (SC): (SC) If ◊pP ∧ □p(P⊃Q), then if P were the case, Q would (still) be the case. From this, Carroll derives two further principles used in the formal version of the mirror argument, (SC*) and (SC’): (SC*) If ◊pP and Q is a law, then if P were the case, Q would (still) be a law. (SC’) If ◊pP and Q is not a law, then if P were the case, Q would (still) not be a law.247 The argument goes as follows: Let P be the proposition that the mirror is in position d. So according to (SC*), if the mirror is in position d in U1, L1 would (still) be a law. From (SC’), Carroll derives the counterfactual that in U2, if the mirror were in position d, L1 would (still) not be a law. Now, in order to assess whether the two counterfactuals given above are true, let us look at the closest possible worlds to U 1 and U2, U1* and U2*. As both are the closest possible worlds respective to U1 and U2, both must 246 See Carroll 1994, pp. 60-62. 247 Carroll 1994, p. 59.

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have the same laws as U1 and U2. But U1* and U2* agree on their Humean base, so according to Humean supervenience, they should have the same laws, which according to the mirror argument, they have not. Note, however, that Carroll allows U1* and U2* to each have a history very different from the history of U1 and U2 in order to account for the difference in the mirror’s position, so that Carroll need not rely on a small miracle to account for the change of the mirror’s position.248 These are two of the most prominent attacks against Humean supervenience as a basic ontological claim. What unifies all the broadly Humean accounts is the basic ontological commitment that there is nothing over and above the occurrent facts. There is some quarrel over what exactly these occurrent facts are, but all broadly Humean philosophers agree that laws are nothing more than patterns that these facts exhibit. So if Humean supervenience fails, so do all of the broadly Humean accounts of laws of nature. It is a big advantage of all of the three counterexamples depicted above that they are not specifically aimed at any particular thesis of Humean supervenience. So what could a defender of Humean supervenience reply to these criticisms? Firstly, the defenders of Humean supervenience, in this case Earman and Roberts, criticise that these arguments rest upon intuitions about the robustness of the nomic, which would render them circular. The first counterexample rests on the intuition that there are uninstantiated laws. In this thought experiment, laws are seen as something robust. Even if there is no collision between X-particles and Y-particles, defenders of the robustness of the nomic hold that there is a law that would hold in case of a collision. Again, this is an intuition a Humean simply does not share. 249 If at no time and in no place a certain conceivable type of event such as the nonexistent collision between X-particles and Y-particles actually takes place, a Humean has no reason to even postulate that there is a law that governs this kind of event, let alone a host of possibly infinitely many possible laws. Thus, as an argument, the counterexample is circular, as it rests on the same intuition it purports to support.250 Carroll’s counterexample is 248 See Carroll 1994, pp. 63-64. 249 Neither does David Armstrong who, as we have seen above, holds that there are no uninstantiated laws. 250 See Earman and Roberts 2005, p. 6.

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harder to refute. Remember that the only change in U1* and U2* compared to U1 and U2 is the position of a mirror which presumably changed the natural laws that hold in U2*. And if a defender of Humean supervenience somehow accounted for the stability of natural laws in U2 and U2*, then he would have to accept that U1* and U2* share the same Humean base but not the laws. So what to make of this problem? That is where Helen Beebee’s criticism sets in. Beebee regards both principles (SC*) and (SC’) as false, which, if she is right, would render the argument invalid. Remember (SC*): If ◊pP and Q is a law, then if P were the case, Q would (still) be a law. For this principle to be valid, it needs to be the case that for any world w, there exists a closest possible world w’ in which P is the case and which is still physically possible in respect to w. Beebee asks us to imagine that worlds w and w’ are deterministic worlds. So without small miracles, the worlds possibly need vastly different causal histories to account for the difference in, say, the position of a mirror. The closest possible world in which P is the case might in fact be a very distant possible world, as the vastly different causal history yields a vastly different distribution of the basic facts. Beebee asks us to imagine another possible world which has the same distribution of basic facts as w, except the position of the mirror at that fateful moment in time. Such a world might not be physically possible, because, if its history is identical to w, you need a small miracle to account for the different position of the mirror. So the closest physically possible world in which P is the case need not be the closest possible world simpliciter in which P is the case. Hence, the closest possible world in which P is the case need not be a physically possible world and thus it should have different laws of nature.251 Ultimately, Beebee’s argument casts doubt on whether U1* and U2* are really physically possible and hence share their natural laws with U1 and U2. Beebee’s argument is compelling. She continues to argue that (SC) and its derivatives (SC*) an (SC’) might be intuitively appealing, but only to those who already share anti-

251 See Beebee 2000, p. 588.

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Humean intuitions: Carroll’s thought experiment merely spells out the intuitions that anti-Humeans already have and hence is no compelling argument against those positions that do not satisfy these intuitions.252 John Roberts tried to refute Carroll’s problem in his beautifully titled 1998 article “Lewis, Carroll and Seeing through the Looking Glass” by attacking some of the premises. Roberts tried to argue that Carroll’s argument in its original form was either incomplete or inconclusive. In his analysis of the arguments, Roberts holds that the genuine possibility of U1* and U2* has to be motivated independently on pain of falling into the same trap as Tooley’s argument which solely relied on the intuitions it was designed to prove. According to Roberts, the only point of introducing U1 and U2 in the first place and not letting the argument start with U1* and U2* is to appeal to the plausibility of the possible worlds U1 and U2 from which to infer the genuine possibility of U1* and U2*. Roberts argues that for this entailment to be sound, however, Carroll needs to introduce further premises that he does not make explicit.253 Ultimately, Roberts’ argument is designed to attack these further premises. In detail, Roberts demands that in order to argue for the possibility of U1* and U2* from the possibility of U1 and U2, one has to show how the change in the position of the mirror that leads to U1* and U2* is physically possible in U1 and U2. That is to say, the total history H of U1* and U2*, which leads to the state of these worlds when the mirror is in position to reflect particle b has to be physically possible in U1 and U2. Accordingly, Roberts demands the introduction of these two further premises: 1. In U1, it is physically possibly that the total history is H. 2. In U2, it is physically possible that the total history is H. 254 Analogously to Helen Beebee’s criticism of the Mirror argument, Roberts argues that these two premises, while necessary for the tenability of the argument, are not self-evidently acceptable for a defender of Humean supervenience or a specific Humean theory of natural laws. Roberts objects that these premises require a non-Humean understanding 252 See Beebee 2000, pp. 588-590. 253 See Roberts 1998, p. 432-433. 254 Roberts 1998, p. 433, my italics.

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of laws of nature and of physical possibility. In order to arrive at the consequence of the argument, the repositioning of the mirror must not come with a change of laws in the respective worlds. Thus, it must be physically possible in both initial worlds that the total history is H and that the laws are still the same. But why should a Humean accept that the closest possible worlds to U1 and U2 in which the mirror is in position d and which share H share the same laws of nature? This seems to rest on the overtly un-Humean intuition that the total history of a world is made up of more or less accidental initial conditions and over and above that, a set of laws that govern how the world will develop given these initial conditions. To a Humean, the repositioning of the mirror and the redistribution of the Humean base in U1* and U2* to yield H might well lead to different laws of nature than in U1 and U2. So in the end, and that is Robert’s conclusion, unless the mirror argument is augmented with premises 1 and 2, it is no progress over Tooley’s question-begging argument.255 But Robert holds that even if augmented with the two additional premises 1 and 2, the mirror argument is no refutation of Humean supervenience. Roberts claims that if confronted with a best system analysis of natural laws which presumes Humean supervenience, the mirror argument fails to be conclusive. The core of Roberts counter-argument is the claim that with a best system analysis, the additional premises 1 and 2 fail to hold. According to the best system view, any world with total history H shares the same best system, among whose axioms L1 either is or is not. If it is, then L1 is a law in all worlds with the total history H, including U1* and U2*. But in that case, U2* would not have the same laws of nature as U2, and hence, total history H would not be possible in U2. Thus, if L1 was a law in all worlds that share the same total history H, then premise 2 would be false. If, on the other hand, L1 was no law in any world with history H, then it would not be a law in U1* which renders premise 1 false, as the premise required H to be possible in U1, which it is not, as L1 is a law in U1 but does not hold in U1* which has the total history H.256 So in conclusion, Roberts argues that the mirror argument is incomplete as it stands and inconclusive against a best system analysis of laws of nature. Thus, ultimately, the mirror argument pits the intuitions that make premises 1, 2, and 255 See Roberts 1998, pp. 434-435. 256 See Roberts 1998, pp. 433-435.

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(SC) and its derivatives seem so plausible against the truth of the best system view. As such, the argument is not better off than Tooley’s argument. As Roberts does not discuss any other Humean theories of laws of nature, his defence of Humean supervenience relies upon the tenability of the best system view, to which we will turn below. In 2005, Earman and Roberts argued that while Carroll’s argument may be conclusive, Humean supervenience is such a desirable theory that Carroll’s argument, while theoretically defendable, should not be taken as a reason to abandon Humean supervenience and replace it with a theory of metaphysically robust laws of nature such as Armstrong’s, Tooley’s or Carroll’s own.257 We have a clash of very powerful intuitions here. On the one hand there is the intuition that laws of nature are nothing over and above the occurrent facts and that there is no genuine necessity in nature, that there is no way in which the facts have to be the way they are, governed by the laws imposed on the facts from above. One the other hand there is the intuition that laws are robust against the occurrent facts. This is the intuition that laws cannot change if you change the occurrent (nomologically possible) facts in the world and that the facts are the way they are because they have to. But to rely on these intuitions renders all the arguments against Humean supervenience discussed above ultimately circular, hence I agree with Beebee that the arguments against Humean supervenience are question-begging. On these grounds, I do not accept that we should give up Humean supervenience. In the following paragraph, let us turn to the two main Humean traditions of theories of natural laws. If we find one of them defendable, we will not bother with the metaphysically much more expensive necessitarian views. The orthodox Humean account on natural laws is the classical regularity theory. This classical account has met some serious opposition over the years, which resulted in refinements and changes to the original classic regularity theory, or naive regularity theory, how its opponents call it. Undoubtedly the most commonly held of these refinements is the joint Mill-Ramsey-Lewis- account (MRL) as it is called by John Earman, who also endorses it.258 Let us see how these views compare. 257 See Earman & Roberts 2005, p. 6. And Carroll, 1994. 258 See Earman 1986, pp. 87-88.

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2.2.1 ORTHODOX HUMEANISM259 As mentioned above, classical accounts identify laws of nature merely by their syntactical form. One of the few contemporary defenders of the classical account is Norman Swartz, whose view will serve as a background here against which to set the MRL-view in the next chapter. In the classical view, a proposition is a law of nature if and only if it is a proposition with the following characteristics laid down by George Molnar, who used this definition to criticise the classical regularity account: D1: P is a statement of a law of nature if and only if: (i) P is universally quantified; and (ii) P is omnitemporally and omnispatially true; and (iii) P is contingent; (iv) P contains only nonlocal empirical predicates, apart from logical connectives and quantifiers.260 Let us consider these conditions. Condition one is pretty straightforward. Condition two excludes false sentences such as “all dogs are elephants” from qualifying as laws of nature. Perhaps unsurprisingly, this condition causes some problems which we will look at below. Condition three secures that a law of nature cannot be an analytically true sentence such as “all bachelors are unmarried”. It also serves to set the regularity theory apart from neo-essentialist theories of laws of nature such as Brian Ellis’ or Alexander Bird’s, who, as seen above, hold that laws of nature are necessary features of our world, given the existence of the fundamental properties. Condition four serves to exclude sentences which refer only to local matters of fact, which may even be omnitemporally true. One such statement could be “all the coins in my pocket are made of copper” or “all the fruits in Smith’s garden are apples”,261 which may well be true for all times 259 Although I do not endorse this view, I shun the name “naive regularity theory”. Orthodox Humeanism is not naive at all, it simply sacrifices a lot of commonsensical intuitions for the sake of ontological parsimony. 260 Molnar 1969, p. 79, my italics and capitals for “P”. 261 Michael Tooley constructs a counterexample to the regularity theory using this

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and places, but restricts the law of nature to one specific location, my pocket. Such facts intuitively seem accidental rather than lawful. This restriction, although intuitively plausible, brings some problems with it. Gerhard Vollmer remarks that strictly speaking, the universe is a location, and hence any law of nature that includes any predicate that refers to our universe would fail to qualify as a law. Moreover, there are some statements which are usually taken to be laws of nature such as Keppler’s laws, which explicitly quantify over the astronomical objects in our solar system and hence include local predicates, which would disqualify them from being genuine laws.262 Note that contrary to the usual perception of the regularity theory it is not entirely true that in Humeanism a law of nature can be identified merely by evaluating its syntactical form, as it is not to be decided on syntactical grounds whether a predicate is for example a local predicate. All these conditions applied, a sentence such as “All students in this room are born in July” would not qualify as a law. In the last few decades, the orthodox regularity theory faced severe criticism and nowadays only very few philosophers openly endorse it. David Armstrong launched the perhaps most ferocious attack on the orthodox regularity theory. Of the many problems he discussed263 we will concentrate on the problem of distinguishing laws from non-laws.

ACCIDENTAL GENERALISATIONS The problem of accidental generalisations arises because in the orthodox regularity view laws of nature are identified (almost) solely by their syntactical form. Intuitively, many sentences can have the required syntactical form that satisfies all of the above mentioned criteria without being a law of nature. While Armstrong’s criticism of the regularity theory regarding accidental generalisations is comprehensive and complex,264 the main idea behind the necessitarian’s unease with the problem of accidental generalisations can be made explicit by use of a very simple argument. Consider for instance Reichenbach’s famous example. Take the following very statement. See Tooley 1977, p. 686. 262 See Vollmer 2000, pp. 215-216. 263 See Armstrong 1983, pp. 11-66. 264 See Armstrong 1983, pp. 11-23.

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two sentences: “All gold spheres are smaller than one mile in diameter” and “All spheres of enriched uranium are smaller than one mile in diameter”. Syntactically, both sentences are equivalent and both comply with the criteria for natural laws that orthodox regularity theory requires: they are true for all times and places, are synthetic universal generalisations, do not contain Goodmanised predicates, contain no local or temporal predicates, no indexicals, etc. So according to the orthodox regularity view, both should count as natural laws, whereas intuitively, there seems to be a difference. The sentence about gold spheres seems to be accidental, as it seems to be an accidental feature of our universe that all the gold spheres in it are smaller than one mile in diameter. There even exists enough gold in the universe to construct such a sphere, and all it takes to build one is an incredibly rich and devoted person to build it. The sentence about the uranium sphere seems different: an object of enriched uranium of that size would simply explode, as the critical mass of enriched uranium is far less than such a massive object would weigh. So, intuitively, the sentence about the solid gold sphere merely states an accidental fact about the universe, whereas the sentence about spheres of enriched uranium seems to be a law of nature, yet both share the same syntactical form.265 The defendant of an orthodox regularity view will react to this problem claiming that it indeed begs the question: if you think that one of these sentences is a law of nature and the other one is not, than you already presuppose that there is a natural necessity at work which makes one of these sentences a law, but not the other. Consequently, an orthodox Humean denies that only the uranium sentence expresses a law of nature.266 Hence, whether you accept Reichenbach’s example as a counterexample to orthodox Humeanism boils down to a matter of intuitions. The orthodox Humean simply does not share the intuition that these two sentences differ in a way that can make one of them a law and the other not. Nowadays, most participants of the debate seem to accept Reichenbach’s argument and reject orthodox Humeanism. Let us sum up. Orthodox Humeanism might be counterintuitive, but it is possibly a defendable position. While rejecting it simply on the basis of intuitions would be quite rash, since intuitions are no secure inference tick265 See Reichenbach 1947, p. 368. 266 See Swartz 2003, p. 65.

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ets to the truth, it is still worthwhile to look for another theory of laws of nature which is not as counterintuitive yet still shares the same basic ontology, which is Humean supervenience. As our main focus has been on necessity in order to evaluate determinism and free will, let us try to make sense of it in orthodox Humean terms. Obviously, the notion of physical necessity simpliciter, defined as occurrence in every nomologically possible world, is sustained in orthodox Humeanism. A nomologically possible world w is a world where the same laws of nature, the same regularities as in our world hold. A physically necessary event then is a event that occurs in every nomologically possible world. We have already seen that this physical necessity simpliciter can only support Humean determinism. Determinism with a vengeance requires the stronger necessity with a verngeance. Consider the fact that there are no gold spheres in our universe that are bigger than one mile in diameter. For the orthodox Humean, this is a law of nature. Hence, it it a physically necessary fact that every lump of gold in the universe is smaller than a mile in diameter. Still, no lump of gold is in any way compelled by that law to be smaller than a mile in diameter. Nothing in the world, especially not the laws, forces lumps of gold to be smaller than a mile in diameter. In that sense, any lump of gold could have been bigger than a mile in diameter, although that fact is physically necessary. What seems to be a contradiction here is in fact none, we are simply talking about two different types of necessity: physical necessity simpliciter and necessity with a vengeance. Orthodox Humeanism obviously supports physical necessity simpliciter, because nomological necessity does not rely on a force in nature that compels, or forces things to be in a certain way. So orthodox Humeanism supports Humean determinism in the sense defined above, yet not determinism with a vengeance.

2.2.2 BEST SYSTEMS Finally, after rejecting all of the accounts mentioned so far for the reasons stated above, we come to a theory of laws of nature that is able to solve most of the problems directed against theories of laws of nature without giving in to excessive metaphysics. The best systems theory of natural laws is deeply rooted in a Humean tradition, yet, as we will see, it is not

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necessarily connected with Humean supervenience, although all the proponents of a best systems view accept Humean supervenience. Among the proponents of a best systems approach of some form or other are David Lewis, Frank Ramsey, John Earman, Jonathan Cohen, Craig Callender, and Markus Schrenk.267 What is common to all best system accounts (BSA) is that natural laws are taken to be universal generalisations as in orthodox Humean accounts, yet the best systems analysis provides an instrument to better distinguish accidental generalisations from lawful generalisations. The best system analyses do not entail Lewisian Humean supervenience. Whilst best systems analyses are based on a scepticism about modal powers in nature, they are neutral towards the question of whether there are mental properties or even whether there is a mental substance for instance. Although I do not follow this route, it is perfectly possible to defend a best system analysis of laws of nature and still be a substance dualist.268 Historically, best system analyses have been put forward by defenders of Humean supervenience such as David Lewis and thus to defend a best system account and still be a substance dualist may strike some as odd, but it is perfectly possible to do so, if for instance our best system was one which contained generalisations that imply the existence of a mental substance. You can be a sceptic about modal forces in nature and still be an interactionist substance dualist. In best systems accounts, a law is a universal generalisation that is an axiom or theorem of each of the systems that offer the best combination of simplicity and strength. A best system is the body of scientific theories and

267 See e.g. Lewis 1973 and 1994, Ramsey 1978, Earman 1986, Cohen and Callender 2009, and Schrenk 2008. 268 Perhaps surprisingly for a defendant of libertarianism, I am not promoting substance dualism here, but it has to be noted that the combination of a best system view with substance dualism is possible, if our best future science proposes a mental substance. Obviously, this would conflict with Lewis’ definition of the subvenient base.

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generalisations that science269 provides us with.270 David Lewis defines these systems as “deductively closed, axiomatisable sets of true sentences. Of these true deductive systems, some can be axiomatised more simply than others. Also some of them have more strength, or more information content, that others.”271 A deductively closed system of sentences is a set of sentences in which all sentences are entailed by a number of sentences, the axioms. The direct consequences of these axioms are the theorems of that system. Applied to science, a deductively closed set of sentences is the body of scientific knowledge given to us by our best sciences. The general idea of best system accounts, regardless of all subtleties which follow, is concisely put by David Lewis as follows: Take all deductive systems whose theorems are true. Some are simpler, better systematized than others. Some are stronger, more informative than others. These virtues compete: An uninformative system can be very simple, an unsystematised compendium of miscellaneous information can be very informative. The best system is the one that strikes as good a balance as truth will allow between simplicity and strength. How good a balance that is will depend on how kind nature is. A regularity is a law iff it is a theorem of the best system.272

It is important to mention that not all best system analyses of natural laws imply that there is only one possible best system. According to David Lewis, who first made this refinement, a sentence is a law iff it occurs as 269 “Science” in this context refers to an idealised future science that gives us a complete axiomatisable set of true sentences. Frank Ramsey describes the best systems as systems that science gave us “if we knew everything” (Ramsey 1978, p. 138). Other authors, including John Earman, do not explicitly refer to an idealised science, yet it is clear that our contemporary science is nowhere near a system of true sentences that is the best combination of strength and simplicity. 270 See Earman 1986, p. 88. 271 Lewis 1973, p. 73 (original italics). 272 Lewis 1994, p. 478. Note that laws are not defined uniformly throughout the debate. Sometimes, they are taken as the theorems of a best system, like in this quotation, or as its axioms (Ramsey 1978, p. 138) or as both (Lewis 1973, p. 73, and Psillos 2002, p. 151.). Although this is an interesting question of its own, I will not pursue it any further in this essay.

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an axiom or theorem in each of the best systems that science gives us.273 This departs from the view held by Frank Ramsey, who only spoke of one best system whose axioms are natural laws.274 To accept that there could be several best systems is related to the problem of language. The problem of language consists of the question if and how best systems differ when formulated in different languages. Some systems may, if formulated in different languages, fare differently in respect to simplicity, strength and the balance thereof. So immediately, the question arises how to compare simplicity and strength between these different systems. The problem could be solved if there was an independent way to define which predicates, or the kinds they refer to, are eligible for appearance in a best system. We will turn to this problem below. In the following, let us first see how the best systems approach fares with the problem of accidental generalisations. In addition to that, we thereafter will have to look at some of the inherent problems the best system theories faces, some of which we already hinted at above, such as the problem of language and doubts concerning the notions of simplicity and strength, their balance and their respective trans-system comparability. Let us see how a best system analysis might answer these threats. Remember the problem of accidental laws described above. Intuitively (pace orthodox Humeans) the sentence “All gold spheres are less than a mile in diameter” is an accidental generalisation, as it seems a contingent fact of the universe and it might very well be that someday a future rich prince will have the devotion and resources to build such a sphere; as Wesley Salmon points out, there would even be enough gold on earth for that task, given that it is possible to extract gold from sea water.275 In contrast, the sentence “All uranium spheres are less than a mile in diameter” is intuitively understood as a law of nature (or entailed by a law of nature), since it is physically impossible to build such a sphere because the critical mass of uranium is much less than it would take to build such a solid sphere of uranium of that diameter, hence the object would simply explode before 273 See Lewis 1973, p. 73. 274 See Ramsey 1978, p. 138. 275 See Salmon 1992, p. 19.

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completion.276 In best systems accounts, contrary to orthodox Humeanist accounts, this intuitive difference can easily be accounted for. While the sentence “All uranium spheres are less than a mile in diameter” serves as an axiom in the system that is the best combination of simplicity and strength, the sentence “All gold spheres are less that a mile in diameter” does not, as it does not add much strength to the best system, but comes at a significant price in simplicity.277

SIMPLICITY, STRENGTH AND RELATED PROBLEMS Let us have a closer look at the criteria of simplicity and strength. A lot of criticism has been provoked by these criteria, but let us define them a bit more carefully before we turn to the problems. The definition of simplicity and strength varies subtly over the different approaches. We could try to get a more detailed grasp of simplicity by carving out the various meanings “simplicity” can have: SIZE: A true deductive system is simple in this sense if it can be sustained with the use of as few axioms as possible. The less axioms a system has, the simpler it is.278 One question that immediately arises is whether conjunctive or disjunctive laws are allowed in this analysis. Any system can easily gain maximal simplicity in size regarding the number of axioms if all of them are formulated as one conjunction or disjunction, rendering this criterion of simplicity rather useless. ONTOLOGICAL SIMPLICITY AND CHOICE OF PREDICATES: Closely connected to the sense of simplicity outlined above, a system can be simple in the sense that it postulates only few theoretical entities. One system that includes all the microphysical entities modern science postulates plus God is in that 276 See Reichenbach 1947, p. 368. 277 Although these two sentences serve as prominent and frequently cited examples of syntactically equal sentences of which one is a law and the other is not, it is a bit misleading here. A sentence about uranium spheres is not a real law of nature, but more of a consequence of a real law about the critical mass of uranium. Hence, The sentence “All uranium spheres are less than a mile in diameter” is not an axiom of a best system, but is entailed by one. For convenience though, let us pretend that it is a law. 278 See e.g. Cohen and Callender 2009, p. 4.

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sense less simple than a system that includes the same entities but no God. Likewise, the sentences that make up deductive systems can also differ in simplicity relative to the language they are written in. Different sets of basic predicates yield different verdicts of simplicity. A language that contains disjunctive predicates as basic predicates for example can express some phenomena in a different manner than a language which does not contain disjunctive predicates. We will turn to this question in greater detail below. STRUCTURE: Systems with the same number of sentences and the same number of ontological commitments can still differ in simplicity. Intuitively, two deductively closed sets of the same number of sentences can still differ in structural complexity depending on the number of relations between these sentences. Cohen and Callender characterise this sense of simplicity as low syntactical complexity.279 Since simplicity is not easily reduced to just one of these options, it comes as a mixture of the three, which are each on its own hard to quantify. A deductive system may be quite simple ontologically, yet be of a comparatively large size. So how does it score in overall simplicity? And how does it fare in overall simplicity compared to another system that is smaller in size yet more complicated ontologically? We will turn to the problems related to these questions below. Compared to simplicity, strength seems more straightforward, but unfortunately it is not. John Earman highlights the fact that informational content cannot be objectively measured, as strength needs to be put into the context of its scientific application. An axiom of the system might not be very strong per se yet could be highly useful if it entails a lot of regularities or phenomena relevant to the intended field of application.280 This relates to the criticism that the notions of simplicity and strength are not only vague, but mind-dependent. What we accept as a useful amount of strength can vary according to the particular field of application and our mental capacit279 See Cohen and Callender 2009, p. 4. 280 See Earman 1986, pp. 88-89. Earman also explains the scientific practice of preferring deterministic laws, because they can be strengthened per se. Given the boundary conditions obtain, they entail all occurrences of related fact at all times past, present or future (ibid.)

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ies. Likewise, what counts as simple or strong might be dependent on context and human minds. What counts as simple to scientists or humans in general need not be simple simpliciter. Moreover, simplicity and strength trade off one against the other with no independent way to decide which to opt for in moments of trade-off – simplicity or strength. To rephrase, not only are simplicity and strength vague and seemingly pragmatic criteria, what counts as the best balance between them also is.281 To sum up, the criteria of simplicity and strength introduce a pragmatic element to the process of deciding what sentences may be called laws. As such it violates the intuition that it is an independent fact of our world what counts as a natural and what does not. These problems will be the pivotal points for our following discussion of the better best system view. Over and above the problem of direct mind-dependence, simplicity, strength, and balance are also dependent on the language the system is formulated in. If there is more than one language available, the question arises how to select the language the best system is to be formulated in. Let us consider these problems now and let us subsequently discuss a novel approach to solve them. As noted by Jonathan Cohen and Craig Callender, simplicity, strength, and balance are immanent criteria, meaning that they are to be defined relative to a system of fundamental predicates, or kinds.282 Hence, the language a system is formulated in matters in assessing simplicity, strength and balance. Simplicity is rather obviously immanent. Different (formal) languages can yield different basic predicates, and with these different basic predicates comes a different measure for what counts as simple. Barry Loewer makes this point by referring to Nelson Goodman’s famous grue-problem: Simplicity, being partly syntactical, is sensitive to the language in which a theory is formulated, and so different choices of simple predicates can lead to different verdicts concerning simplicity. A language that contains ‘grue’ and ‘bleen’ as simple predicates but not ‘green’ will count ‘All Emeralds are green’ as more complex than will a language that contains ‘green’ as a simple predicate.283 281 See Cohen and Callender 2009, p. 6. 282 See Cohen and Callender 2009, pp. 5-6. 283 Loewer 1996, p. 109. Original italics and quotes.

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Similarly, but a bit more surprisingly, strength is an immanent criterion in Callender’s and Cohen’s sense. The number of sentences that are deducible from the basic axioms of a system, that is the informational content of the system, depends on the choice of basic predicates, on the language in which the system is formulated. Lastly, balance fares no better than simplicity and strength in isolation. In order to strike a balance between simplicity and strength, both criteria need to be defined properly, which is only possible against the background of a chosen language. Hence, balance is dependent on the choice of basic predicates as well. The fact that simplicity, strength, and balance can only be defined against the backdrop of the language the system is formulated in leaves us with a problem. Imagine different systems that compete for the title of ‘best system’, but which are formulated using different basic predicates. Intersystem comparison of strength, simplicity, and balance seems impossible. Hence, it is impossible to tell which of the systems really is the best system and hence, there is no certitude about which are the laws of nature. Callender and Cohen call this problem the problem of immanent comparisons.284 There are different options how to respond to that problem. The most obvious response to the problem of immanent comparisons is to adopt a theory of natural kinds or natural predicates, as David Lewis does. David Lewis arrives at this conclusion after considering how to prohibit trivial generalisations such as ∀x(Fx), where ‘F’ is a predicate arbitrarily defined to holds for all things in a world where an arbitrary system S holds. If the predicate F was allowed as a genuine predicate, the trivial generalisation could even serve as a very simple best system.285 Lewis circumvents this problem by positing natural properties, to which the most basic predicates refer. Thus, systems can be compared regarding simplicity and strength, because all best systems share the same set of basic predicates. To posit natural kinds or predicates makes it possible to designate a correct language amongst all the rival languages that compete in formulating the system. A correct language in that sense is a language whose predicates refer to natural kinds. More precisely, in a correct language any predicate refers

284 See Cohen and Callender 2009, pp. 5-6. 285 See Lewis 1983, p. 42.

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to one and only one natural kind.286 A predicate such as “green” for example refers to the natural property of being green, while a predicate such as “grue” does not refer to any natural property. Neither does any disjunctive or conjunctive predicate in general ever refer to a natural kind in that view. To adopt natural kinds thus eliminates the problem of language since there is only one language, the correct one, in which to formulate the best systems, any system can be compared respective simplicity and strength. So while the comparison of simplicity and strength remains immanent to the language the systems are formulated in, it becomes objective since there is only one language any good system can be formulated in. So far, so good, but to posit natural kinds raises the question of how to identify the predicates that really refer to a natural kind and those who do not. And even more worryingly, David Lewis does not provide an answer to this question. He merely proposes that any anti-nominalism regarding predicates will do, but does not embrace a specific position. So it is up to living defendants of best systems accounts to choose a version of ant-nominalism to go with the best systems account. One possible answer to that question could be to propose an evolutionary theory that over time, humans have acquired a special ability to identify natural kinds, which we probably inherited from our ancestors who needed the ability to quickly and reliably tell friends from foes, poisonous from edible food, and dangerous from safe situations. This amounts to an evolutionary argument to the effect that humans have the ability to reliably identify natural kinds because they would not have lasted the vicious struggle for survival if they did not have that ability.287 Several problems bother that strategy. Even granted that this evolutionary story is correct, how are we justified to think that what works in the jungle, where we are able to tell mice from vicious tigers, works equally well in the realm of solid state physics. Even if our predicates that refer to vital kinds such as predators and food stock reliably refer to natural kinds it could still be possible that our ability to identify natural kinds fails in contexts that

286 See Lewis 1986, pp. 63-69. 287 See van Fraassen 1989, p. 52.

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are quite different than those that were predominant when we evolved that ability. There is, as van Fraassen put it, no close connection between the jungle and the blackboard.288 A second option how to identify natural kinds would be to point towards science again. In this view, the correct vocabulary would be the one in which the most successful best system is formulated at the end of science. In this view, we would know that the vocabulary the most successful best system is formulated in is true, because systems formulated in the correct vocabulary tend to be more successful than systems formulated using an incorrect choice of basic predicates. This view would contain an inference to the best explanation: The best explanation for the success of an axiomatic system is that it is formulated using a correct choice of basic predicates, that is that its basic predicates refer to natural kinds. Three issues arise with such a view. Firstly, van Fraassen offers a thought experiment designed to show the deficits of this view. Imagine an ideal science and a best system formulated in natural predicates. Now imagine a rogue scientist who submits a system which is simpler and more informative, but employs a language of new theoretical terms which do not refer to natural kinds. Van Fraassen correctly claims that this system would most probably be the one preferred by the scientific community because of its simplicity and strength.289 The onus of proof lies on the defendants of the natural kind view that this scenario that a system which uses unnatural predicates can never be simpler and stronger than a system formulated in a natural language. Secondly, van Fraassen argues that given there even is such a thing as a natural kind, the best way to find out whether a kind is correctly identified is to see whether it is a basic predicate of (one of) the best system(s). And if that is the case, how should it be possible to guide science towards the usage of certain predicates? In the case of the thought experiment, how would we even know which of the two best systems refers to natural kinds, given that the only way to tell that a predicate refers to a natural kind is that it is used in a successful scientific theory?290 Thirdly, overlooked by van Fraassen in this context, since he does not 288 See van Fraassen 1989, p. 52. 289 See van Fraassen 1989, p. 53. 290 See van Fraassen 1989, pp. 53-54.

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reconstruct the the argument for the claim that the most successful system will be formulated in a language referring only to natural kinds as an inference to the best explanation, there is the overall concern whether abductive reasoning is a justifiable form of inference.291 Taking all this into account, the view that those systems formulated in a correct language will always prove to be the most successful in the vicious jungle of scientific theories does not seem very promising. Hence, the problem of how to identify the correct kinds remains.

BETTER BEST SYSTEMS Recently, another kind of best system approach has been put forth, which is designed to solve the above-mentioned puzzles regarding natural kinds and can provide a theory of special science laws, which the classical MRL view could not for reasons which we will see below. To provide a possibility for special science laws would prove particularly helpful in the context of this essay because there is good reason to think that if there are laws which govern human behaviour, these laws would be laws of psychology, of neuroscience, and of biology. Jonathan Cohen, Craig Callender, and Markus Schrenk endorse such a view that they call the “better best systems account of lawhood” (BBS).292 Their view is that a more flexible MRL-account, which they call “relativised” MRL fares better than MRLaccounts which rely on the notion that all best systems have to share a common – once and for all fixed – set of predicates with which to formulate the best system in a number of respects. Relativised MRL is the claim that the choice of predicates used for the formulation of a best system is dependent on the needs of scientific practice. In this view, it is possible to parallelly sustain different best systems each developed according to specific areas of application. These systems are not transcendently comparable, but at least any system that uses a certain stipulated vocabulary would be comparable to any other system that uses the same vocabulary. According to Callender and Cohen, this relativised MRL allows for special science 291 See for example van Fraassen 1989, pp. 131-150 for a critique, or Lipton 2004 for a very thorough defence of inference to the best explanation. 292 See Cohen and Callender 2009, and Schrenk 2008.

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laws which refer to supervenient kinds.293 Consider the opposite: One particular vocabulary, most probably the vocabulary of fundamental physical properties, is the single “correct” vocabulary in which to formulate any best system. According to Callender and Cohen, in such a view, special science laws cannot be accounted for, because either are the supervenient kinds such as entropy or simple macro-properties such as volume or pressure impossible to translate into the vocabulary of fundamental physical properties, or, if it is indeed possible to translate them, their translation would be so long and complicated that generalisations over these translations would come at such a great price in simplicity that they would never be accepted as axioms of any best system.294 And even if the common vocabulary is not the vocabulary of fundamental physical properties, but perhaps a vocabulary of predicates referring to macro-properties, there still are problems. One is that once you distinguished a single set of predicates with which to formulate all best systems, be it by stipulation or because it refers to perfectly natural kinds, alternative systems which use a different vocabulary are not comparable to the best systems formulated in the common vocabulary – you will never know which system is the correct one as the basic mistake might not lie within the particular best systems but in their choice of a vocabulary. Relativised MRL now serves to avoid such concerns. Cohen and Callender demand that the vocabulary be stipulated according to the particular needs of scientific practise, which results in a multitude of best systems, each best in relation to the area of application. But within these areas of application, each system shares the same stipulated set of predicates and hence are comparable regarding strength, simplicity, and balance.295 At this stage an opponent of BBS could object that to allow for relativised stipulated languages, the choice of predicates becomes completely arbitrary and that the resulting laws do not tell us anything about nature, but only about the stipulated language it is formulated in. Cohen and Callender avoid this problem by proposing what they call “explosive realism of natural kinds”. They hold that nature allows for infinitely many ways of carving up, result293 See Cohen and Callender 2009, p. 24. 294 See Cohen and Callender 2009, pp. 14-15. 295 See Cohen and Callender 2009, pp. 22-24.

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ing in infinitely many different sets of basic predicates. Which of these sets of basic predicates to chose for a particular best system is a decision dictated by the needs of (the special) science, but the predicates themselves are natural: that nature allows for many ways of carving it up does not entail that the resulting sets of predicates are not natural.296 According to Cohen and Callender, another advantage of relativising MRL is that it allows for scientific change, as the sets of predicates used to formulate best systems are merely stipulated, they can be revised as science progresses. The stipulated sets of kinds are not stipulated once and for all, but can be adapted to changing demands and scientific progress.297 With this relativisation, Cohen and Callender also do away with the classic demand that a best system is what a future ideal science provides us with – a demand which rendered all concrete questions of intersystem comparability, simplicity, and strength a matter of the far future. While I am very sympathetic overall to BBS, it should be noted that it has some problems that arise because of the admission of best systems for each of the special sciences.298 For one, there still is no transcendent criterion of comparison if someone comes up with a best system that uses a different vocabulary than the stipulated one that the scientific community agreed upon for this particular field of enquiry. The second overall discomfort with Cohen’s and Callender’s approach is that it deviates from the usual MRL in the way that it does not treat the best system as the outcome of an ideal future science, but as an alterable and fallible systematisation of scientific knowledge. While I am sympathetic to this move in general, I fear that it might be problematic to maintain the basic principles of MRL if the best system is not the systematisation of the final product of final science: Is it really possible to construct a deductively closed set of sentences out of our present scientific knowledge? John Earman proposed to treat the terms “deductive system” and “theory” as synonymous.299 As long as the best system is taken to be a future, final theory of everything, we can char296 See Cohen and Callender 2009, p. 22. 297 See Cohen and Callender 2009, pp. 17-20. 298 See Reutlinger and Backmann, conference talk given on the 27th of January 2011 in Cologne. 299 See Earman 1986, p. 88.

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itably assume that this future theory fulfils the requirements for being a consistent deductively closed set of sentences. But does e.g. current Psychology meet the requirements for being a such a system in the sense that we could organise it so neatly that every sentence of it would be entailed by one of the theory’s axioms or theorems, without containing any logical inconsistencies? I fear current psychology may not be so consistent, and maybe almost none of the special sciences are, at least not in their current form. But that is a topic for further inquiry. Secondly, there is a problem with the character of special science laws, if they are taken as contingently true sentences. Marc Lange famously holds that allowing non-universal special science laws can open up a dilemma. These laws are non-universal in the third sense given above: they do not hold under any circumstances. As stated by Nancy Cartwright, most (if not all) special science laws do not instantiate perfect regularities.300 Lange concludes that special science laws, if expressed as perfect regularities, are false, which is the first horn of the dilemma. But if they are augmented with ceteris paribus clauses of the style “all Fs are Gs, given that nothing interferes”, then the second horn looms in the sense that the special science laws are prone to become trivially true.301 If Cohen and Callender want to allow special science laws, they have to solve this problem. Markus Schrenk, however, proposed a solution to this problem: He holds that we can identify a non-universal special science law as true if we can list all exceptions to the generalisation explicitly, rather than just adding “...given that nothing interferes”. If a proposition thus amended still fits into our best system, then it is a law. This way, we could arrive at true special science laws that are not trivial.302 Thirdly, special science laws often include idealisations. Economical laws e.g. often assume perfect competition, which includes e.g. that every participant of a market has complete information, or that no participant of a market has price-altering influence, and the like. Take for example the law of demand: “Under the condition of perfect competition, an increase of demand of a commodity leads to an increase of price, given that the quant300 See Cartwright 1983, p. 45. 301 See Lange 1993, p. 235, my italics for Fs that are Gs. 302 See Schrenk 2008, pp 127-129.

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ity of the supply of the commodity remains constant”.303 Strictly speaking, these laws assume perfect conditions that never, or rarely, occur. Hence, it may be argued that these laws have no instances.304 In isolation, it may be unproblematic to allow single laws with no instances, if they e.g. offer a great deal of strength without a big cost in simplicity. According to John Carroll, Newton’s first law might be such a law.305 But where to draw the line? In the end, we may end up on a slippery slope to a best system that has no instances at all. Lastly, there is the problem that relativised stipulated sets of kinds as a basis of our best systems violate the criterion of realism. Stathis Psillos holds that regularity views are realist theories in the sense that they are committed to the reality and the mind-independence of the proposed entities.306 Again, BBS’ commitment to stipulated relativised sets of kinds turns out to be problematic. What set of predicates we chose to describe a certain area of reality is dependent on the demands of the special science in question, and hence, it is partly dependent on human minds. But if the choice of basic predicates is partly mind-dependent, then it is also partly mind-dependent what the laws are. This is clearly a violation of Psillos’ demand for realism. The defendant of BBS could react to this charge by pointing out that while the choice which set of basic predicates to use may be mind-dependent, each set of basic predicates remains natural. According to explosive realism, nature allows for infinitely many ways of being carved up, but it does not allow any set of predicates unless it is natural. So the defendant of explosive realism may respond that the fact that the selection of one of the natural sets of basic predicates is mind-dependent does not entail that we do not have every reason to be realist about the entities the predicates refer to.

303 See Roberts 2004, p. 159 and Kincaid 2004, p. 177; cited after Reutlinger, Schurz, and Hüttemann 2011. 304 For the comprehensive classical discussion, see Cartwright 1986. 305 See Carroll 1990, p 193. 306 See Psillos 2009, p. 133. Note that he discussed this litmus test for realism in the context of a regularity view of causation. Nevertheless, these two criteria can be applied ti regularity views of laws of nature just as easily.

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To date, BBS is still a very young view, and hence it should not come as a surprise that it comes with its own share of problems. Let us await Cohen’s, Callender’s and Schrenk’s reaction to these problems before we give our final verdict. Until then, the proposal remains highly interesting, because it addresses a big problem for the MRL-view, which cannot accommodate the laws of the special sciences because of the MRL’s view reliance on a single language, which cannot accommodate supervenient kinds properly. The ability to accommodate special science laws is a unique feature amongst the theories of laws of nature discussed in this volume. As we have seen, both necessitarianism and dispositional essentialism hold that the properties which account for the natural laws have to be fundamental, which is why these views cannot give an account for special science laws. Before we sum up chapter 2.2 in general, let us evaluate BS and BBS. Orthodox Humeanism and BS/BBS are both true to Humean supervenience and in both views, laws are nothing but regularities which have no compelling force. Orthodox Humeanism and BS/BBS also share the same approach to physical necessity. Remember the distinction drawn between physical necessity simpliciter and necessity with a vengeance, and, accordingly, Humean determinism and determinism with a vengeance: Humean Determinism: The world w ϵ  is Humean deterministic just in case for any w’ ϵ , if w and w’ agree at any time, then they agree at all times.307 Determinism with a vengeance: The world w ϵ  is deterministic with a vengeance just in case for any w’ ϵ , if w and w’ agree at any time, then they are compelled to agree at all times by the natural laws that all the worlds in  share. Physical necessity simpliciter: A fact is physically necessary simpliciter iff it occurs in every world that shares the same laws as the actual world. Necessity with a vengeance: A fact is necessary with a vengeance iff it is compelled by a law of nature. 307 Compare Earman 1986, p. 13.

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In BS/BBS, an event is physically necessary if it occurs in all the worlds which are such that the same axioms and theorems are the basis of the best systems that order the scientific knowledge of these worlds. So in BS/BBS, a fact is physically necessary if it occurs in every world which shares a certain subset of regularities with our world, yet obviously, these laws do not compel the facts to occur. So like orthodox Humeanism, BS does support Humean determinism, but not determinism with a vengeance, since does not sustain necessity with a vengeance. Yet, BS is not as brutal to our intuitions as orthodox Humeanism is, and since its problems are far less severe than those of the necessitarian accounts and the arguments against Humean supervenience in general have failed to be conclusive, I propose that BS, possibly in the Cohen/Callender/Schrenk sense of BBS, is the best compromise between tenability, compatibility with our intuitions, and ontological parsimony available on the market of theories of laws of nature. The BBS view offers the very unique feature of giving a detailed account of how special science laws could be possible. But, and as it lies at the core of the argument that comprises the very raison d’être of this book that fact is worth repeating, BBS does support neither necessity with a vengeance, nor determinism with a vengeance. Let us take a look at the broader picture before we leave the debate about laws of nature behind and finally move on to the free will debate and the question how these are connected. In chapter 2, we have evaluated a considerable number of theories of natural laws. Amongst these theories, we rejected the necessitarian theories for not being able to solve the inference and the identification problem or, in the case of neo-essentialism, for its inability to support counterlegals, for its arguments against quidditism, and for its proposal that the facts are compelled by metaphysical necessity. Humean accounts, however, have not proved to be uncontroversial, either. But we have seen that the arguments against Humean supervenience in general are not conclusive and are even question-begging. Amongst the Humean accounts of laws of nature, Schrenk’s, Cohen’s and Callender’s better best system view seems very promising. Best system views of any kind have their own share of problems, such as the problem of immanent comparisons or the problem of language. But these problems are no more severe than those of the necessitarian theories, and the Humean theories

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propose a more austere ontology. In this essay, we do not need to refine our theory of laws of nature to any greater extent than we have done above. To turn to the topic of this essay: What does Humeanism tell us with regard to necessity and hence, what does it tell us with regard to determinism as discussed in chapter 1? Necessitarianism would have provided us with the notion of natural necessity with a vengeance which we would have needed to satisfy the Jamesian intuition about determinism as rendering our world, our future, as a cold and unalterable iron block. Best system views do not postulate any nomological forces in nature which enforce the world’s lawabiding behaviour, but are still able to distinguish between accidental and lawful generalisations. MRL- and BBS-views do not turn the future into an unalterable iron block, they do not leave us in a cold, fixed world. In chapter 4, we will finally see what this entails for the free will debate and whether a Humean account on laws of nature, which allows for strict laws, can account for free will in a libertarian sense.

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3 LIBERTARIANISM Now that we have discussed determinism and laws of nature, let us finally turn to libertarianism. Traditionally, libertarianism has been viewed as an incompatibilist theory of free will, as it requires the existence of real alternatives at the moment of decision, which seems to be incompatible with determinism. But in chapter 1.3 we have distinguished between two senses of determinism: a weaker, Humean sense of determinism, and a stronger, necessitarian account of determinism with a vengeance, which requires that apart from entailment by universal generalisation, determined events must be necessitated to come about. That this stronger, necessitarian claim is incompatible with the principle of alternative possibilities in the way that they are required by libertarian theories is uncontroversial, but could Humean determinism maybe compatible with it? To ascertain, let us start by analysing the main features of libertarian theories, before we turn to the question how and whether they conflict with both sorts of determinism in the following chapter. As all modern libertarian theories comply with the principle of alternative possibilities, modern libertarian theories can further be divided into two categories by how they deal with the principle of control. While I will not discuss each and every sort of libertarian theory of free will available on the market today and will not consider each and every aspect in which they can possibly differ, we will have to consider one main way how to distinguish libertarian theories, i.e. how they treat the question how and if free actions are caused. Remember the main hypothesis of this entire essay, which states that a Humean libertarian theory of free will which fulfils the libertarian criteria of alternativism and control can be made compatible with a Humean view on laws of nature and determinism. We have to take a look at how we, as agents, bring about our own deliberate actions and how the ‘elbow room’, to use Dennett’s lovely phrase,308 for the agent is created, i.e., how the flow of deterministic events is disrupted so that there can be real alternatives for the agent to choose from. 308 See Dennett 1984.

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At first we will take a look at noncausalist theories of free will. There are two types of noncausalist theories. Weaker theories hold that free actions need not be caused in a particular way to be free, whereas strong noncausal theories hold that free actions must not be caused at all. By denying any causal relevance of intentional mental events, the noncausalists circumvent the problem of mental causation.309 In this book, noncausalist theories will not take centre stage, not because they are fundamentally wrong – although I think they are – but because it is the very aim of this book to defend a version of libertarianism which is as strong as possible against the backdrop of a broadly Humean view of laws of nature. And dropping the causal relevance of reason-states does not make libertarianism any stronger a claim. Nevertheless, for the sake of completeness, we will take a brief look at the main noncausalist theories, and the chief arguments that show why they are wrong. In the second and third part of this chapter we will turn to causalist libertarian theories. Causalist theories are theories that state that actions, or decisions for that matter, are caused. Causalist theories can be divided even further into agent-causal theories and event-causal theories. As mentioned earlier, agent-causal theories postulate a special type of causation for free actions that is different from normal, everyday event causation. This special kind of causation serves to evade certain arguments that challenge libertarian theories of control which involve causation by the agent's intentional states. If agent-causalists are to be believed, free actions are caused by the agent, who is not an event but a substance, and hence need not to be caused herself. The agent as a substance in this view is something like a prime mover unmoved.

309 In fact, The problem of mental causation, i.e. the question of how mental events can cause overt actions, can be completely ignored in this essay because Humean libertarianism as I propose it does not presuppose psychophysical dualism. In fact, it does not presuppose any particular theory of the mind, as long as whatever is or represents a reason-state, i.e. having a belief or a desire, be that a nonphysical mental event or a neurological event, can cause an action. As we will see below, none of the event-causal libertarian views presuppose dualism either.

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Event-causal libertarian theories on the other hand do not need this special kind of causation, which can be viewed as an advantage, as agent causation has been attacked as “panicky metaphysics”.310 In event-causal views, actions are caused by intentional mental events such as beliefs and desires, but indeterministically so. The main advantage of event-causal theories is that they do not necessarily propose an agent-substance and a peculiar form of causation. Event-causal theories will not be discussed at great length in this chapter, because the main arguments against them will be discussed in chapter 4, where we also learn more about these theories’ details. As you can see from these rather opinionated opening remarks, it is event causation that will be preferred for my own take on Humean libertarianism. It would be very peculiar indeed to propose a theory of laws of nature that complies to Humean supervenience, and then turn to a theory of free will which proposes a peculiar kind of causation and possibly immaterial, causally independent agents. Again, as in our discussion of laws of nature, it has to be noted that this short chapter is no thorough refutation of noncausalism and agent-causation. But it does serve to show why I take event-causation as the most promising libertarian view. Before we turn to the main attacks against event-causal theories of libertarianism in chapter 4, where Humean libertarianism will finally take shape, let us try to investigate the most common libertarian theories in a little more detail.

310 See Dennett 1984, p.76. Dennett first applied this judgement to agent causation instead of libertarianism in general, against which the phrase was originally coined by Peter Strawson (see Strawson 1962, p. 25). See e.g. Kane 2007, p. 25, for one of the numerous applications of that phrase.

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3.1 NONCAUSALISM311 Noncausalist theories of free will do not do not claim that free actions have to be caused in a certain way, but they do hold that free actions must not be causally determined.312 Moreover, most noncausalists hold that free actions must not be caused at all. The two best known defenders of noncausalism are Carl Ginet and Hugh McCann.313 Both are committed to the view that although free actions are intentional, the action's being intentional and free requires that it is accompanied by an intentional mental event, but not caused by it.314 To understand the noncausalists’ account of free action, consider an action such as willingly raising one arm. This action is accompanied by an intentional mental act, a volition. This volition, however, need not cause the bodily motion of raising my arm. The agent’s impression of control over the free intentional action is due to its being accompanied by the volition. Ginet calls this feeling to be in control of intentional free action “actish phenomenal quality”,315 McCann holds that decisions are intrinsically intentional, and thus that the intentionality of an act is a feature of this act, but not its cause.316 To repeat, for the agent’s raising his arm to be free, the noncausalists do not allow it to be actually caused by the the appropriate reason-states. In this essay, we will for two important reasons not consider noncausalist theories any further. Noncausalist theories fail to give a reasonable account of control, which is one of the two main criteria for libertarian theories. By the same token, they also fail to provide good reason-explanations for free human actions. Secondly, noncausalism is epistemically questionable. As yet, there is no reason to claim that overt actions do not have a physical cause. 311 Robert Kane and Timothy O’Connor use the term “simple indeterminism” instead of “noncausalism” (See e.g. Kane 2006, pp. 53-57 and O’Connor 1993, p.502). I will stick to the more commonly used term “Noncausalism” here, although Kane’s term has the advantage that it is more appropriate for weak noncausalism, which does not require that free actions must not be caused. 312 For an overview over noncausal accounts, see Clarke 2002 and Ginet 2002. 313 See e.g. Ginet 1990, 1995, 1997, 2002, and 2007, as well as McCann 1998. 314 See e.g. McCann 1998, pp. 148-151 and Ginet 2002, pp. 386-389. McCann holds that although actions are intrinsically intentional, which accounts for the actions being done for a reason, they are not caused by reason-states. 315 See Ginet 1997, p. 89. 316 See McCann 1993, p. 9.

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Let us turn to the first criticism. While noncausalist theories respect alternativism, because they hold that free actions may not be deterministically caused, they fail to give a reasonable account of control. Remember our tentative outline of noncausal control as given in the introduction: Noncausal control = An action is controlled by the agent iff it is accompanied by a reason to act which is causally inefficacious in relation to the action. Traditionally, libertarians hold that for any action to be free, it needs to be controlled by the agent in one of the senses discussed in the introduction, which usually includes causal control. While standard libertarian theories diverge over the question what causes free actions, events such as the occurrence of a belief or a desire, or agents, most libertarians agree that control requires causation. Noncausal theories, however, fail to account for any of these senses of control. Noncausal theories to place free actions, or any actions for that matter, completely outside the agent’s causal reach: if the agent’s intentional mental acts accompany her actions, but do not cause them, how can the agent be in control of his actions? To experience an actish phenomenal quality, as Ginet calls it, or to maintain that an action is intrinsically intentional, while the intention remains causally irrelevant, does not place the action within the agent’s control according to the critics of agent causation. The charge is that, to put it bluntly, in the noncausalists’ theories free actions may feel like they under the control of the agents, but they are not. Ginet characterises the role the actish phenomenal quality plays as follows: The only way I can think of to describe this phenomenal quality is to say such things as “It is as if I directly produce the sound in my ‘mind’s ear’ (or the image in my ‘mind’s eye’, or the volition to exert), as if I directly make it occur, as if I directly determine it” – that is, to use agent-causation talk radically qualified by “as if”.317

317 Ginet 1990, p. 13.

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So to the noncausalists, the presence of intentions to act and the fact that the actions are not causally determined suffice to establish control.318 To refute the noncausalists’ sense of control, we need to find find a counterexample to the claim that actions are uncaused but still under the control of the agent. If we are able to give an example of an action that fails to be free because the agent had no causal control over it, yet still the appropriate causally ineffective reason-state occurred, we could refute noncausalism. To illustrate this point, Alfred Mele and Randolph Clarke point out that actions might be preceded by intentional mental events but be caused by something else, be it an uncontrollable impulse or a different mental event. In these cases, Clarke and Mele hold, we would not call the action having been done for that reason the intentional mental event constitutes. But then the action’s being accompanied by an intention, which might not be causally relevant for it, cannot constitute control.319 Alfred Mele gives the following thought experiment to illustrate this argument. An agent has the intention to open a window in order to let some fresh air into her room. A mad scientist decides to trick the agent and manipulated the agent’s brain insofar as the neuronal representation of the intention to open the window is disconnected from the act of opening the window. Instead, an unconscious process installed by the scientist causes the overt action to open the window. But the scientist manipulated the agent so that she still perceives her own intention to open the window and feels as if she opens the window on her own terms. She does not realise that the causal link between her intention and the action was severed. Mele holds that this action would not be seen as being under the control of the agent, because it did not have the appropriate cause, i.e. the agent’s intention. That the intention was present does neither explain the action, nor does it put it under the control of the agent.320 Ginet holds that the argument is question-begging, because it presupposes what it wants to prove, i.e. that free actions are normally caused by reason-states.321 I disagree. Mele’s argument amply illustrates the conceptual links between control and causal efficacy of reason-states. In no reasonable sense of the phrase could 318 319 320 321

See e.g. McCann 1998, p. 180. See Clarke 2002, p. 358, and Mele 1992, p. 253. See Mele 1992, p. 253. See Ginet 2002, pp. 389-390.

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the action in Mele’s thought experiment be done for the agent’s intention to open the window. If Mele is wrong and neuroscientists should some day find out that reason-states are not causally relevant for conscious actions, Mele would by force of his own argument have to conclude that we are not free. Mele does not presuppose that actions are caused by reason-states, but demonstrates that they have to, if we are to call them free. This objection can also be put in terms of the argument from luck. While, as we will see below, every libertarian theory struggles with the argument from luck, the argument hits noncausalism with full force. To put it briefly, the argument from luck states that if an agent could have done otherwise, even if the entire history of the universe until his action were identical, then his action is merely a matter of luck. And if an action is a matter of luck, it cannot be under the control of the agent.322 We will deal with this argument in much greater detail in chapter 4.2.1, where a solution will be discussed. This solution, however, will not be available to the noncausalist, because it states that while an element of luck is inextricably tied to free actions, the principle of control might be saved given that the agent’s very own beliefs and desires are causally relevant for her actions. This move, whether it is successful or not will have to be seen in chapter 4.2.1, is unavailable for the noncausalist who holds that free actions are not caused by reason-states. I agree with Randolph Clarke in his agreement to Timothy O’Connor’s position that the mere presence of a causally irrelevant reason-state does not suffice to establish control.323 For the same reason the noncausalists fail to satisfy the criterion of control, they fail to give an account of reason-explanations for free actions. The critics of noncausalism hold that if actions are not caused by the appropriate reason-states, then it is not possible to give a reason-explanation of any action. To illustrate this criticism, Randolph Clarke gives the following example: consider two people, Sue and Ralph. Both stay in different rooms, Ralph is asleep. Sue, the agent, has two desires to act: to get her glasses, which are in Ralph’s room, and to wake up Ralph, because she 322 See Mele 2006, pp. 6-9 for an exposition of the argument. 323 See Clarke 2003, p. 20, and for O’Connor’s view that Clarke references and agrees to, see O’Connor 2000, pp. 25-26. For a classic argument to the same effect, see Davidson 1980, p. 9.

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desires his company. She then enters Ralph’s room to retrieve her glasses and thereby wakes him up. Although she wanted to wake Ralph up, she did not intend to do so by entering his room, since she merely wanted to get her glasses. According to the noncausalists, an action is rationally explicable if the action concurred with an intention the agent had prior to the action. In this case, however, although Sue had the desire to wake Ralph up prior to entering his room, she did not act on her desire to wake him up, and hence the action of entering Ralph’s room cannot be correctly explained by citing her desire to wake him up. Instead, the only correct reason-explanation for her action is that she intended to get her glasses. Hence, stating intentions that an agent had prior to his action is not sufficient to give a reason-explanation of the action. So Clarke concludes that a reason-explanation of an action must not only refer to an intention the agent had prior to the action, but also that this intention was causally relevant for the action. In this example, Sue’s desire to get her glasses was causally relevant and hence a correct explanation for her entering the room, while her desire to wake up Ralph was not causally relevant and hence no explanation for her entering the room.324 Let us very briefly turn to the second argument against strong noncausalism. As yet, there is no empirical evidence that suggests that there are uncaused overt actions. There are arguments that supposedly show that sometimes, or even always, actions are not caused by the right causes, i.e. that they are not caused by reason-states. But that does not entail that they are uncaused altogether. The influential experiment by Benjamin Libet for example to which we will turn below in greater detail allegedly shows that free actions are not caused by the conscious intention to act because the conscious intention to act supposedly occurs after the action has been initiated.325 But that does not show that the action was not caused at all, only that intentions to act might be epiphenomenal. Even if uncaused events are possible in microphysics, it still would have to be proven that events such as these play a significant and systematic part in the physical bases of human action. So in the light of modern neuroscience, the noncausalists’ claims are completely unfounded. 324 See Clarke 2002, p. 360. 325 See Libet 1983 and 2002.

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In fairness, it has to be noted that noncausalists such as Carl Ginet do not simply develop their noncausalist accounts out of thin air. In the case of Carl Ginet for example, the noncausalist account of (free) action is formed after an extensive critique of event causation and agent causation.326 This criticism will not go unnoticed here and will be considered in the following two paragraphs on these positions. But if it is possible to uphold a causalist theory of free will in the light of this criticism, why should we settle for noncausalism? So for now, let us turn to these more popular theories of human action and let us see whether we can uphold one of them.

3.2 CAUSALISM: AGENT CAUSATION Varieties of agent causation have been proposed by a number of philosophers. In the early modern period, the idea was proposed by Thomas Reid and George Berkeley.327 In recent times, agent causation has been revived by Roderick Chisholm, who however subsequently distanced himself from the proposal that agent causation is categorically different from event causation.328 For this reason, we will mention Chisholm, although he was responsible for resurrecting the idea, only in passing. Other authors who propose a theory of agent causation include Randolph Clarke, Timothy O’Connor, and John Thorp.329 Even Kant’s original ideal of a “Kausalität aus Freiheit” which he defined as a distinct sort of causation that applies only to free actions and which is categorically different from normal causation in nature and hence does not have to bend to the rules that apply to causation in nature,330 has recently been resurrected by Peter Rohs.331 It has to be noted, however, that Kausalität aus Freiheit is not exactly identical to agent causation, but it shares the same basic idea: i.e. that there are two types of causation.

326 See e.g. Ginet 1990, pp. 6-14. 327 See Reid 1969 [1788] and Berkeley 1998 [1710]. 328 See e.g. Chisholm 1995, p. 95-101. 329 For Clarke, see e.g. Clarke 1993, 1996, and 2003. For O’Connor, see e.g. O’Connor 1995, 1996, 2000, 2002, and 2005. For John Thorp, see Thorp 1980. 330 See Kant, KrV B 560. 331 See Rohs 2009.

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Theories of agent causation share with noncausalism the view that free actions must be decoupled from the physical chain of causes and effects. To put free actions firmly in the control of the agent, proponents of agent causation hold the view that free actions and free decisions (i) must not be caused by any physical event, as every physical event is in turn (possibly deterministically) caused by another physical event, etc., which would place the action beyond the control of the agent, and (ii) the free action must be brought about by the agent himself, by a kind of causation that is only available to conscious agents. Usually, accounts of agent causation do not only apply to free actions, but to intentional actions in general.332 However, proponents of agent causation disagree on the exact causal relata of agent causation. Randolph Clarke for example proposes an integrated account that is designed to reconcile agent causation and event causation. Clarke holds that reasons, which are intentional states, cause the action, whereas the agent causes the reason’s causing the action when he decides which of the alternative reasons to act for.333 Timothy O’Connor, the other great contemporary proponent of agent causation, is convinced that when deciding what action to perform, agents cause intentions to act in a certain way for a certain reason, and that it is really these intentions that are causally responsible for the action to happen.334 It is a very interesting field of philosophical enquiry what exactly the agent is taken to be in theories of agent causation. Theories of agent causation are often dualistic, but this is no formal requirement to qualify as a theory of agent causation. Timothy O’Connor holds that Roderick Chisholm’s original account which took the agent as a substance which is different from the physical substance was dualistic.335 Timothy O’Connor also holds the mind to be a nonphysical substance that emerges from the physical states of the brain.336 Other proponents of agent causation have held that while certainly some sort of distinction between the physical 332 For thorough overviews over theories of agent-causation, to which I owe a lot of the structuring of this chapter, see Clarke 2003, ch. 8-10, Clarke 2008, and O’Connor 2002. 333 See Clarke 2003, pp. 136-137. 334 See O’Connor 2002, pp. 349-350, or O’Connor 2000, p. 113. 335 See O’Connor 2002, p. 342. 336 See O’Connor 2000, p. 109.

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realm and the agent must be made in order to account for the resulting two types of causation, this claim does not strictly entail substance dualism.337 However, what unites all theories of agent causation is the claim that there are two sorts of causation: one that accounts for the everyday physical events, and a categorically different kind of causation that accounts for (free) intentional actions. While in the physical world, events are the causes of other events, when it comes to free actions, it is the agent, and no event within or external to him that causes his actions. This entails that some physical events, i.e. for example our actions have no physical cause but an agent-cause. This obviously requires that the actions the agent causes (or his intentions to act in O’Connor’s view) via agent causation have to be causally undetermined by other physical events. There must not be a physical event-cause for an action so that the agent can cut in the flow of physical events and bring about some change with his own sort of causation. This is the aspect of theories of agent causation which marks them out as incompatibilist theories. Also, it puts the onus of proof unto the defenders of agent causation as it has to be proven that the according physical events have no physical event-cause. We will see to this problem below. The main feature of accounts of agent causation is then that the agent, qua being an agent, is not causally determined by physical events. Roderick Chisholm, who resurrected the idea of agent causation in the last decades of the 20th century, expressed this feature as follows: “In doing what we do, we cause certain events to happen, and nothing – or no one – causes us to cause those events to happen.”338 To put it in other words: the agent, which in Chisholm’s theory is a substance of his own and hence whose acts need not be caused by any event, is something of an unmoved mover in accounts of agent causation. And according to Chisholm, the only way to really put free actions under the control of the agent is to accept another sort of causation apart from the usual event causation that accounts for everyday causal relations in nature. Chisholm holds the view that no event could ever cause a free action, as this event-cause would have been caused by another event, and so forth until the chain of events stretches over 337 See e.g. O’Connor 2002, pp. 342-344 for a brief overview over this debate. 338 Chisholm 1982, p. 32.

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events that are outside and beyond the control of the agent. Hence, the principle of control would be violated. Agent causation solves this problem as in this theory, the cause of the action needs not be caused by any event altogether, but by the agent, via an intrinsically intentional form of causality unbeknownst to the physical world.339 Randolph Clarke’s theory of agent causation, however, is an exception to the rule that all accounts of agent causation require that free actions are never caused by an event. Clarke allows that free actions can be indeterministically caused by prior events and by the agent. Suppose the following scenario: an action has a probability of .6 to be caused by a previous event. Now the agent decides to perform that action and so she does. According to Clarke, it is possible that this action was caused by the agent as well as indeterministically by a preceding event, which might as well have been a reason-state. So Clarke allows for causal overdetermination of free intentional actions. By this, Clarke seeks to reconcile freedom with the causal principle which states that every event has a cause and that agents “are part of the causal order”.340 Note also that Clarke does state that every free action is overdetermined, as is entailed by the above cited claim that although the agent qua being agent causes every free intentional action, the agent is not detached from the causal order. Clarke even goes further to claim that free actions require the prior occurrence of certain events like for instance the acquisition of certain reasons to make these actions physically possible. In Clarke’s view, the agent acts as some kind of reason selector, he causes by his decision a certain reason or set of reasons to act by.341 The notion that certain types of events may be systematically causally overdetermined, i.e. regularly have more than one cause, has for instance been challenged by Jaegwon Kim, who holds that mental causation in nonreductive physicalism is impossible because it implies systematic over339 See Chisholm 1982, p. 25. 340 See Clarke 1993, pp. 193-194. Note that the causal principle would not be violated, even if the action was only caused by the agent. Clarke probably means the principle of the causal closure of the physical world, which states that if a physical event has a cause, then it has a physical cause. For various formulations of the causal closure principle, see Lowe 2000, pp. 573-574. 341 See Clarke 1993, p. 194.

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determination.342 The possibility of overdetermination has been defended e.g. by Theodore Sider.343 Carl Ginet criticises integrated accounts such as Clarke’s for their appeal to causal overdetermination. Ginet claims that if an event as e.g. the acquisition of a certain intention, plays a causal role in acting, why should it not be possible that in some cases, actions may be performed without the extra help of an agent causing the action alongside the causal relevant event? What use is an agent if the action can be caused independently without her by some event?344 Clarke’s response to this objection is that it is necessary that free intentional actions be caused, at least to some extent, by an agent, and not only by an event. The action might be causally overdetermined, but it is no intentional free action if it is not also caused by the agent. Moreover, Clarke states that it is indeed a law of nature that free actions are co-caused by agents. In Clarke’s view, it is nomologically necessary for every event that is an action to be brought about by an agent-involving event (such as forming an intention) as well as the agent himself. It is thus nomologically impossible for an action to be caused only by an agent or only by an agent-involving event.345 Clarke’s introduction of laws of nature at this point is problematic and will be dealt with shortly below. In order to evade the problem of overdetermination, Clarke discusses the view that the agent-involving event and the agent could be interpreted not as overdetermining causes, but as contributing causes. The difference is that in cases of causal overdetermination, the two (or more) causes are each sufficient causes for the effect, even if they occurred in isolation. Consider a classic example: Two hunters stalk and simultaneously shoot a deer. The two bullets hit the deer at exactly the same time and each bullet inflicts wounds that would have been fatal if having occurred in isolation. The deer’s death then is supposed to be overdetermined by the two causes, each of which would have been sufficient even in isolation. In the case of contributing causes on the other hand both causes could not serve as sufficient causes individually, but could only be jointly sufficient for the effect. Clarke likens human action to cases of causation in physics where several 342 343 344 345

See Kim 1993, p. 247 and 1998, pp. 44-45. See Sider 2003. See Ginet 2002, p. 397. See Clarke 2003, p. 145.

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separate causes are only jointly sufficient to produce a certain effect. He gives the example of a flammable substance which both needs a rise in temperature as well as an influx of oxygen to combust. The influx of oxygen and the rise in temperature each would not have been sufficient for the flammable substance to light. In this case, it is a matter of natural law that each of the contributing causes could not have produced the effect if they had occurred in isolation. Clarke maintains that the same holds for free intentional actions. Neither the agent-involving event of having a reason to act nor the agent could, as a matter of law, cause free intentional actions in isolation.346 While this argument serves to refute the charge that Clarke’s integrated account amounts to systematic overdetermination, it still remains an interesting question what exactly the natural law is supposed to be that integrates event causation and causation by the agent qua being a substance. As we will see shortly below, Clarke cannot answer this question satisfactorily.

Now that we have discussed the most common theories of agent-causation, let us focus on their main advantages and disadvantages. Initially, agent causation seems to have two main advantages, which we will discuss below: It explains how an action can be intentional and how the agent controls his actions. Thus, it provides answers to the libertarian criterion of control. The argument from intentionality states that if there was only one kind of causation that applied to everyday physical events as well as actions, it would not be intelligible how an action could be done for a reason. According to the proponents of agent causation, the intentionality of intentional actions could not be mediated by event causation. Events such as the occurrence of certain patterns of neuronal activity, they claim, cannot account for any sort of intentionality.347 The other main advantage of agent causal accounts is commonly regarded to be the way these theories deal with the argument from luck, which we have briefly discussed above and will return to in greater detail in chapter 4.2.1. On first impression, theories of agent causation can rebut the argument from luck more easily than theories of event causation. As mentioned above, the argument 346 See Clarke 2003, p. 146. 347 See O’Connor 2002, p. 339.

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is meant to show that an action, which was indeterministically caused by some event, was not in the control of the agent in the sense that it was not up to the agent which of the open alternative possibilities was brought about.348 Consider again a simple action such as raising one’s arm to order a glass of wine. If the principle of alternative possibilities is satisfied, then prior to the agent’s decision to rise her arm it was open whether he would raise her arm or not. But if it was the indeterministic occurrence of some event inside the agent that brought about her raising her arm, it was not up to her whether that event occurred or not. Likewise, the action, i.e. the agent’s raising her arm, did not occur intentionally, but because it was caused by chance. To put it differently: traditionally, libertarian views require that free actions are not causally determined by preceding events, but if they are indeterministically caused by a preceding event, how can the action be up to the agent and be under the control of the agent? Theories of agent causation provide a way to explain how the agent comes into play: before (free) intentional actions, the chain of causal determination is broken and the action is not causally determined by any preceding event, but now the agent steps in and causes the action she wants to perform, so the action is under the control of the agent and done for a reason.349 But theories of agent causation also have some serious disadvantages, even if we for a moment grant that they can cash in their advantages. In the course of this chapter, we will discuss two objections against agent causation, although there are a lot more:350 firstly, there is the problem that agent causation does not seem to be compatible with standard views on causation, and secondly, there is the problem that the theory’s ontological extravagance seems as a panicky ad-hoc-solution to some of the most persisting problems of free will.

348 For a depiction of the argument, see Mele 2006, pp. 6-9. 349 See e.g. O’Connor 2002, p. 340. 350 For an overview, see e.g. Kane 2005, pp. 47-52.

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INCOMPATIBILITY WITH STANDARD ACCOUNTS OF CAUSATION Arguably the most striking of the above-mentioned problems in the context of this essay is that agent causation is not compatible with any Humean picture of causation and laws of nature, regardless of how exactly the causal relation or the agent is understood on the various theories of agent causation. Agent causation, the indeterministic causing of an action by an agent, cannot be understood in terms of a Humean analysis, which is taken here not as an orthodox regularity view, but as any account of causation which is compatible with Humean supervenience. Any broadly Humean analysis of laws of nature and causation treats the causal relata as events. It is particularly dubious how agents qua substances fit in the Humean subvenient base. Remember Lewis’ account of Humean supervenience, which stated that everything there is supervenes on the spatiotemporal distribution of local qualities.351 We have seen above that Lewis’ account was problematic because of its insistence on locality, but nevertheless it should be clear what the core idea is: that everything there is supervenes on the occurrence of facts, on events. Clarke acknowledged in 1993 that agents qua perduring substances cannot function as causal relata in orthodox regularity accounts causation which treat causation as the instance of a lawful regularity, and neither can agents fulfil that role in counterfactual accounts of causation.352 According to Clarke, the agent qua substance figures as a cause, and not the agent’s having certain properties, which would be an event and so could easily figure as a cause in regularity accounts.353 Ten years later, Clarke states that while agent-causation is not compatible with any of the most common Humean accounts, it is not entirely impossible to combine an account of agent-causation with a Humean view of laws of nature and causation, if the latter was modified to accommodate agents as causes.354 That agent causation is not compatible with a Humean view of laws of nature and causation without requiring major modification of the according theories of laws and causation is in itself not yet an argument against agent 351 352 353 354

See Lewis e.g. 1994, p. 474. See Clarke 1993, p. 197. See O’Connor 2002, p. 344. See Clarke 2003, p. 187, n. 6.

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causation. But agent causation would be rendered all the more implausible if it was also incompatible with other standard views of causation. We will not attempt to give a thorough overview of all available theories of causation and whether agent causation is compatible with them, but since Clarke and O’Connor both propose either an ADT-account or a dispositionalist view, we have to investigate whether these are really compatible with agent causation. Clarke for example at first tied agent causation to an ADT-view of laws of nature and causation,355 and later argued that agent causation can be combined with either the ADT-view or dispositionalist accounts.356 We have seen in chapter 2.1 that the Armstrong-Tooley-Dretske view and the dispositionalist view are questionable. Let us first investigate the combination of agent causation with the ADT-view, and then turn to the question whether agent-causation can be combined with dispositionalism. Clarke begins his analysis by stating that agent causation is not distinguished from event causation by the type of relation, but by the type of relata. Contra the early Chisholm, he does not take agent causation to be an intrinsically intentional relation between an agent and the event that is her action.357 Clarke maintains that the agent causes her actions in the same way as one event causes the other, the only difference being that the first relatum is an agent and no event. As the agent causes her actions by ordering her reasons to act, the action is intentional, and the relation itself does not need to be. Clarke roots for the Armstrong-Tooley-Dretske view of laws of nature and causation, which he takes not to require that it is events that cause events. Clarke maintains that it is possible that the necessitation relation which the defendants of the ADT-view suppose holds between the causal relata can also hold between agents and events, not only between events.358 Clarke even gives an example of how the according law could look like. For this law to hold, three requirements have to be met: Clarke takes is as a necessary truth that if an action is performed freely, then it was caused by the agent according to reasons. Furthermore, Clarke takes it to be necessary, 355 See Clarke 1993. 356 See Clarke 2003, pp. 186-193. 357 As mentioned earlier, Chisholm later held the view that agent causation is just a subtype of event causation (See Chisholm 1995, pp. 95-101. 358 See Clarke 2003, p. 190.

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but not logically sufficient, for being a free agent that the agent must be capable of rational reasoning and self-governance. The natural law then is taken to be that “if an agent possessing that capacity [of rational reasoning and self-governance] acts on reasons, she acts on free will”.359 Clarke takes this to be a statement of contingent natural necessity, the kind of necessity with which laws in the ADT-view hold. This law together with the necessary truths given above is supposed to entail the causal relation between agent and action.360 But does this really qualify as a law in the ADT-view? The statements of necessity given above do not seem to express contingent natural necessity as envisaged by Armstrong. I cannot see any contingent necessity holding between two universals here, merely a definition of which conditions must be necessarily fulfilled for an action to be a free action. The “law” cited above is a definition, not a law. It entails by definition that any free action has to fulfil the requirements listed in the definition to be called a free action, but not that being an agent contingently necessitates acting for reasons. Clarke seems rather to misconstrue the ADT-view here. What ADT take as a law, a relation of contingent necessitation between two universals, is not arrived at by giving a definition of the concept of free action and throw in a statement of contingent necessity. In a more recent attempt at reconciling the ADT-view with agent causation, Clarke states that it is a natural law that the agent possesses certain causal powers which enables her to cause free intentional actions, given the relevant agent-involving events such as having reasons or the intention to act according to these reasons occur.361 But as the ADT-view construes laws of nature as relations between properties, any natural law governing agent causation must refer to a property that the agent possesses. Clarke tries to accommodate this by stating that the causal power an agent has is conferred to her by her having a certain property:

359 Clarke 1993, p. 198. 360 ibid. 361 See Clarke 2003, pp. 190-193.

137 […] [T]he need for the agent to be a coproducer in the situation is said to stem from possession by the agent of the property that confers an agent-causal power on her. That property, it is said, confers on the substance possessing it a causal power that, as a matter of natural law, is exerted when and only when that individual acts. It is the causal law governing agent causation that is said to tie the two causes together in this way.362

The gap that Clarke has to bridge is that in the ADT-view, the causal relata as well as the relata of natural laws are properties, whereas in agentcausation, the first relatum in both can also be an agent. To bridge this gap, Clarke holds that an agent can figure in ADT-relations of nomological necessity because the agent’s possessing a certain property bestows him with the causal power to act as a cause on his own.363 He admits that it is a puzzle “how […] the exercise of that causal power [can] be anything other than the substance’s possessing that property’s (an event’s) standing in the causal relation to an effect, as it is in cases of the manifestation of causal powers carried by other properties […]”.364 Let us not be fooled here. It does not suffice to claim that the agent has certain properties that bestow him with causal powers. If it is not the agent’s instantiating the property (an event) which is the cause, its not compatible with the ADT-view. Remember that for David Armstrong, only fundamental properties can figure in laws of nature. What fundamental properties there are is up for our best future science to decide.365 It is hard to see why Armstrong should allow for agents qua substances to figure in nomic relations then. Moreover, we have seen that Armstrong takes laws to be higher order universals, i.e. universals that hold between universals. I cannot see how an agent as a substance might fit in here without seriously altering – damaging – Armstrong’s view. Introducing a property which bestows causal powers but does not itself stand in a causal relation to the effect is plainly mysterious. If Clarke really wants to hold on to the ADT-view, he has to submit to the view that it is the agent instantiating a certain fundamental property which is what causes the action. This he cannot accept on pain of giving up 362 363 364 365

Clarke 2003, p. 146. See Clarke 2003, pp. 192-193. Clarke 2003, p. 192. See Armstrong 1983, p. 83.

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agent causation as the view that it is no event, but the agent qua substance that causes free actions. First Clarke gave up the notion that agent causation was a different type of causation and committed himself to the view that agent causation differs from event causation only in terms of the causal relata, and now it seems he would have to give up this idea as well, if he wants to hold on to the ADT-view. It seems the ADT-view is not compatible with agent causation at all and that Clarke’s integrated account by adoption of the ADT-view collapses into a theory of event-causation. So ultimately, his view faces a dilemma: either he accepts the ADT-view of laws and causation and gives up agent-causation, or he sustains agent-causation and has to accept that the causal relation remains mysterious. Like Clarke, Timothy O’Connor is also concerned with integrating his theory of agent causation within a nonreductive account of causation. Like Clarke, he also maintains that causation cannot be reconstructed in terms of a regularity account, but that it is an irreducible relation of causal production.366 Although it was originally O’Connor’s stance to combine agent causation with dispositionalism, Clarke as well recently discussed this proposal.367 O’Connor’s and Clarke’s attempt at integrating agent causation and dispositionalism are very similar, so we will treat them jointly. In order to integrate agent causation in a nonreductive theory of causation, O’Connor claims that agent causation, like regular event causation, is grounded in an object’s possessing certain properties which confer certain causal powers upon the object. In cases of event causation, it is the object’s instantiating these properties, i.e. events, that cause other events. In cases of agent causation, things are a little more complicated. O’Connor acknowledges that it cannot be the agent instantiating certain properties that causes his actions, as this would be nothing but event causation. 368 So according O’Connor, the agent causes his actions directly via the causal powers she possesses. These causal powers she possesses are grounded in the agent having certain properties that confer these causal powers upon her. O’Connor takes properties to have a categorical as well as a dispositional aspect.369 These properties bestow the causal powers upon the object. These 366 367 368 369

See O’Connor 1996, pp. 144-145. See Clarke 2003, pp. 188-190. See O’Connor 2000, p. 113. See O’Connor 1996, p. 144.

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causal powers are exercised if the object is placed in the right circumstances. O’Connor calls these properties which bestow causal powers onto the agent without themselves figuring in causal relations “choice-enabling properties”.370 In order to avoid his view collapse into event causation, O’Connor maintains that it is not the properties themselves that cause actions via their instantiations, but the agent, who happens to have the causal capacities she has because of the properties she instantiates: The agent-causal relation itself is conceived simply as follows: Wherever the agentcausal relation obtains, the agent bears a property or set of properties that is 'choiceenabling' […]. But this ‘active power’ – the causal power in virtue of which one has freedom of will – is not characterized by any function from circumstances to effects (as is the case with event causal powers). For the properties that confer such a capacity do not themselves (in the appropriate circumstances) necessitate or make probable a certain effect. Rather, they (in conjunction with appropriate circumstances) make possible the direct, purposive bringing about of an effect by the agent who bears them.371

Two questions arise from the quote given above: Does this view really avoid falling into the same trap as Clarke’s attempt at integrating the ADTview into agent causation, and even granted that it does, can it really be integrated into the dispositionalist accounts sketched in chapter 2.1.2? I fear that the answer to both these questions will be negative. Firstly, as it is the case with Clarke’s attempt at integrating the ADTview with agent causation, It is utterly unfathomable how the agent can have the causal powers which enable her to directly cause her actions bestowed upon her by the properties she has without these properties’ instantiations figuring in causal relations. Exactly as in Clarke’s case, It does not suffice to vaguely gesture towards properties that bestow causal powers upon the agent without giving a more detailed account of how exactly they can do so without figuring in the causal relation. But even given that O’Connor can solve this problem, the question remains how he can integrate his view on agent causation into a dispositionalist account. In 370 See O’Connor 1996, p. 145. 371 O’Connor 1996, p 145, original italics.

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the dispositionalist view, it is the instantiation of the stimulus that causes the manifestation of the disposition. This instantiation of the stimulus is an event. To pick a very recent work on this subject, Alexander Bird for example tries to elucidate a dispositional account of causation in a paper that will be published as a part of an anthology edited by Anna Marmodoro. In it, he tries to develop a dispositional account of causation from what he calls the “simple dispositional analysis” (SD): A causes B when A is the stimulus of some disposition and B is the corresponding manifestation.372 For agent causation to be integrated in this view, it would have to be possible that an agent can count as a stimulus for a dispositional property. I cannot see how that would be possible, given the standard way of conceiving the stimulus as a spatiotemporally located event. Andreas Hüttemann also put forth the idea that dispositions can provide us with an analysis of causation. In his view, the dependence between cause and effect is spelt out by counterfactuals, which in turn are grounded in dispositions. Hüttemann also holds that the causal relata are events.373 Again, it does not suffice for the agent-causalist to postulate that causal powers are grounded in properties to integrate agent causality into nonreductive theories of causation and laws of nature. In these, it is always events which are causes. To simply vaguely hint that the agent has certain properties that bestow her with the power to act on her own and act as a stimulus for certain dispositions, but that these properties do not need to be actually instantiated or manifest, does not suffice to integrate agent causation and dispositionalism. If Clarke and O’Connor really want to offer an account where the agent qua possessing certain properties that provide her with the causal powers to act without any instantiations of properties being the cause of her actions, they cannot simply reach for one of the existing nonreductive theories, they either have to modify them radically or they have to propose a completely new causal theory. The failure to integrate agent causation into any existing theory of causation and laws of nature makes agent causation all the more implausible.

372 See Bird, forthcoming, p. 2 of the manuscript. 373 See Hüttemann 20071, p. 218.

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So we have seen that agent causation is not only incompatible with any standard Humean account of causation and laws of nature, but also with the two discussed types of nonreductivist theories as well. We have to be careful here: to show that agent causality is incompatible with any standard view on laws of nature is no thorough refutation. So in the context of this essay, the objection that agent causation is incompatible with regularity views seems to beg the question: if it is the purpose to show that a Humean theory of laws of nature and causation and a weak sense of determinism can be made compatible with a certain sense of libertarianism which I want to defend, I cannot reject agent causation on the grounds that is is not compatible with a regularity theory. However, as chapter 2.2 has hopefully shown, there are good reasons to accept a best system account of lawhood and with it a broadly Humean view of causation. If that is correct, then a theory of action which is incompatible with an independently supported theory of laws of nature and causation loses some of its initial plausibility. Before we wrap up, let us focus on one more problem of theories of agent causation: its ontological extravagance and they way the defenders of agent causation arrive at it.

AD HOC EXTRAVAGANZA Perhaps the most influential of counter-arguments against agent causation is that it is ontologically demanding. Causation is a difficult enough concept even if one supposes that there is only one sort of causation, but to propose that there are two sorts of causation, by events and agents, is a claim so blatantly ontological extravagant that it is in dire need of motivation. The worry is that it seems ad hoc, if it cannot be independently motivated apart from its capability of stopping the regress of causes of actions and reasons that finally reaches conditions outside the agent’s reach, and filling the gap between a physically undetermined action and a conscious agent. That is why agent causation has been described as “panicky metaphysics”.374 Another worry about agent causation is that it is arrived at by stipulating solutions that are mysterious. Even granted that agent causation can actually account for free intentional actions, it arrives at that solution 374 See Dennett 1984, p.76, and Kane 2007, p. 25.

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by proposing an ultimately mysterious kind of causation which is intrinsically intentional and can only relate agents with the intentional actions that the agent brings about. The fact that the agent is actually causally undetermined by physical events is not demonstrated, but stipulated as a definiens of being an agent. Robert Kane discusses this problem in the context of the problems of control and rational explicability of actions. Stipulate that the agent is a prime mover unmoved and that the special causality he commands is as the defenders of agent causation propose, i.e. an intrinsically intentional kind of causation, and you get intelligibility and control for free. To Kane and others, this seems like a cheap solution: For agent-causalists to say that choices or actions that are immanently caused [immanent causation is Chisholm’s term for agent causation, M.B.] by agents cannot by their very nature be caused by prior events seems to answer this problem [i.e. how the agent and the agent alone can be the source of her actions, M.B.] by stipulation. In saying such a thing, agent causalists would seem to be defining immanent causation so that it cannot on principle be caused by other events. If so, they would be getting the result they want for free and not by honest toil.375

As can also be seen by its reluctance to be integrated in standard views of causation, agent causation remains a mysterious concept. This criticism is summed up by van Inwagen, who holds that: “In fact, I find it [agentcausation] more puzzling than the problem it is supposed to be a solution to. Obscurum per obscurius!”376 Moreover, it is obvious that the agent has to be moved in some way by the outside world, and hence cannot strictly be a prime mover unmoved. In order to make well-informed decisions, the agent must at least be able to perceive what is going on around her, so some events have to have a causal influence on the agent. What the defender of agent causation has to show is how, while events can have a causal influence on the agent when she is e.g. perceiving the outside world, she is unmoved – causally independent – when making a decision. The proponent of agent causation has to show 375 Kane 2005, p. 48 (original italics). 376 Van Inwagen 1983, p. 151.

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how it is possible that in some circumstances, events can have a causal influence on the agent, but not in cases of decision. This is very puzzling indeed. We will leave agent causation at that. If it is possible to defend a libertarian account of free will which is less problematic, I see no reason to propose agent causation. In fact, I hope we have seen above that noncausalism and agent causation are so problem-laden that if it is impossible to uphold a theory of event causation, we should better think of abandoning libertarianism altogether. So let us investigate whether we can give a tenable account of event-causation.

3.3 CAUSALISM: EVENT CAUSATION Event causalism is the view that there is only one single kind of causation which holds in the cases of (free) intentional actions and in everyday physical processes alike. It is the claim that the causal relata of actions and decisions are events, and events only. What sets (free) intentional actions apart from everyday physical processes is not the kind of causation involved in bringing about these actions but how it is caused by an event, given that a number of conditions are fulfilled. In other words, event causation is the theory according to which (free) intentional actions are not set apart from physical processes by the type of relation, but by the relata. According to event causalists, the causes of (free) intentional actions are manifestations of reasons taken as events. Event-causalism thereby accounts for the intentionality of actions not by proposing an intrinsically intentional sort of causation, but by identifying the intention within the cause, i.e. the reason for which the action is undertaken. Among the most prominent contemporary defenders of event causation are Alfred Mele,377 Mark Balaguer,378 Peter van Inwagen,379 and the most prolific defender of 377 See e.g. Mele 2006 and 1996. 378 See e.g. Balaguer 2010. 379 Peter van Inwagen defends event-causation, which should not be mistaken for a thorough defence of libertarianism. Peter van Inwagen holds the view that free will is neither compatible with determinism, nor is it in fact compatible with indeterminism (see van Inwagen 2002, p. 168). Yet, he claims that we clearly have and experience free will (see van Inwagen 2002, p 159). He concludes that free will is mysterious. But

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event-causal libertarian accounts: Robert Kane.380 Alfred Mele occupies a special position in the debate, because he holds that he is agnostic about the truth or falsity of incompatibilism and compatibilism. But he does hold that regardless of whether compatibilism or incompatibilism is true, there nevertheless are free and responsible actions, a view that he calls “agnostic autonomism”. Mele proposes strategies for the libertarian as well as for the compatibilist to answer the most prominent problems of these accounts. Since the proposals he offers for libertarianism are thoroughly event-causal, he will be treated as a proponent of event-causalism here, even if he officially remains agnostic about the question whether incompatibilism is actually true.381 In this chapter, I will not give a detailed account of all event-causal libertarian views, but will instead try to outline the common features of the most common accounts of event causation. I will discuss some of the most prominent contemporary event-causal theories and the main arguments against them in chapter 4, where I will also try to defend Humean libertarianism. My account of the core position of event-causalism will be based on Randolph Clarke’s own attempt at defining a core that most event-causalists can agree to, which he calls the “unadorned view” of event-causation.382 This view is a very simple version of what is more commonly called a “non-valerian” account. Non-valerian views locate the time of indeterminacy directly before the decision, not at some earlier time. A view of this kind is put forth in greatest detail by Robert Kane. In chapters 4.1.3.3 and 4.2.1.3, we will also discuss Mark Balaguer’s recent account. From this view we have to distinguish a second kind of event-causal accounts in which the action itself may be deterministically caused, but its cause may be indeterministically caused. As reason to act for example may indeterministically come to mind and then deterministically cause the action. Clarke calls these views “deliberative accounts”, which more commonly go by the name of “valerian accounts”.383 Valerian accounts have any tenable view of free will, van Inwagen holds, should be event-causal (See van Inwagen 2002, pp. 170-175). 380 See e.g. Kane 1996, 1999, 2002, 2005, 2007. 381 See Mele 2006, pp. 4-5. 382 See Clarke 2003, p. 31. 383 See Clarke 2003, pp. 57-69, esp. 58 n.2.

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been put forth prominently by Alfred Mele and Laura Ekstrom.384 We will turn to Mele’s valerian view in greater detail in chapter 4. For the broad exposition of event-causalism in this chapter, we will focus on non-valerian views. Non-valerian event-causalism, according to Randolph Clarke, is the view that a free action is nondeterministically and nondeviantly385 caused by some events within the agent. These events are instantiations of the agent’s beliefs, desires, and intentions to act. The agent thereby exercises active control over her actions, which are, as they are caused by her beliefs, desires and intentions, done for a reason. The agent has the power to do otherwise because her actions are indeterministically caused, which means that there are alternative courses of action, which the agent can also bring about. The most outspoken defender of non-valerian libertarianism, Robert Kane, claims that there is a competition of reason-states which can be causes of the agent’s actions, and which of them prevails in the end is a matter of indeterminism.386 The indeterminism thus is not always only a matter of whether or not an agent acts at all, i.e. if her reason-states happen to cause an action, but which reason-state or set of reason-states happen to be causally effective. Remember our two conditions for free actions: alternativism and control. In e.g. Kane’s event-causal libertarianism, alternativism is satisfied by the condition that there is a competition of reason states, each of which could prevail to indeterministically cause the action. The control requirement is fulfilled because it is the agent’s own reason states, her own beliefs, desires and intentions which cause her actions. The

384 See e.g. Mele 1995 and 2006, and Ekstrom 2000 and 2003. 385 For a discussion of deviant causation of actions, see Audi 1986, pp. 525-535. One example for a deviantly caused action is that an agent decides to raise her arm in order to greet a friend, but her arm is temporarily paralysed. Unaware of this, her decision to raise her arm activates a nearby machine that by emitting radiation causes her arm to raise. Moreover the agent was tricked to believe that her reason-states nondeviantly caused her waving. (See Audi 1986, p. 526.). In addition to these cases of deviant causation by reasons, there is the problem of deviantly acquired reasons. We will turn to deviantly acquired reasons again in chapter 4.2, where we will discuss control. 386 See e.g. Kane 2007, pp. 28-31.

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complete following chapter will be devoted to illustrate the most common objections raised against event-causalism in general to the effect that event-causalism cannot satisfactorily meet these conditions. Kane remarks that event-causal views of free will are often adopted by hard determinists and compatibilists in order to refute libertarianism.387 Obviously, hard determinists and incompatibilists who accept event-causal views of free will have to reject the view that any of the causal relations between beliefs, desires, and intentions and the action are indeterministic, thereby arguing against alternativism and the power to do otherwise. Arguments to this effect will be considered in chapter 4.1.3. As Kane’s account of event-causalism is in accord with Clarke’s, we can accept Clarke’s reconstruction of his opponents’ view as accurate. At first glance, event-causal theories circumvent some of the problems that haunt agent-causalism. Firstly, Event-causal theories of action are in accord with the most common theories of laws of nature and causation which state that causes are events, and events only. Event-causation fits any of the most common reductive and nonreductive theories available nicely. It is completely neutral to any of the views discussed in chapter 2. Regularity accounts and ADT-views, as well as dispositionalist accounts all take the relata that figure in laws of nature and in causal relations to be events, i.e. the instantiations of certain properties. They disagree on what exactly these properties are and how they are related, but not that it is the instantiations of properties that cause anything. Secondly, theories of event-causation are ontologically less extravagant. There has to be no causally independent perduring substance which can act as a cause but is uncaused, there is no causally undetermined agent as an unmoved mover. Theories of event causation in general do not have the aura of achieving their goals by ad hoc stipulations. But event-causal libertarian views face some problems as well, which we will discuss in the following chapter.

387 See Kane 2005, p. 61. Kane gives a very detailed account of event-causal libertarianism which he develops in a number of papers. He especially tries to give an account how the competition of reason-states can be reconciled with modern physics and neuroscience (See e.g. Kane 2007, pp. 28-31). We will turn to his account in more detail in chapter 4.1.3.2

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4 OBJECTIONS AGAINST EVENT-CAUSAL LIBERTARIANISM We will now turn to the most prominent attacks against libertarian theories and how the accounts of Robert Kane, Mark Balaguer and Alfred Mele, which I take to be archetypical event-causal views, can answer these arguments. Firstly, we will take a look at the consequence argument, which is originally an argument against control, but which, in conjunction with the hypothesis that determinism is true, can show that the agent cannot do otherwise. It is in the context of this argument that we will finally explore the notion of Humean libertarianism as incompatible with determinism with a vengeance, but compatible with Humean determinism. Secondly, there is the objection expressed by the Frankfurt-style cases that the power to do otherwise is no necessary condition for freedom. Thirdly, there is the worry that while the event-causalists’ view on action might be correct, there actually is no indeterminism which could account for the power to do otherwise. So event-causal theories of action might be correct, but libertarianism false. These objections will be considered in chapter 4.1. In chapter 4.2, we will explore two arguments to the effect that within the framework of event-causation, there is no satisfying sense in which an agent is in control of her own actions. The most prominent argument against control is the argument from luck, which is designed to show that an action which is indeterministically caused is ultimately just a matter of luck and hence not controlled by the agent. The second most prominent argument against control is the argument from Libet’s experiment which has been construed as to show that actions are caused subconsciously and not by reasons. In the course of this chapter, Humean libertarianism will also finally emerge. When discussing each of the above-mentioned arguments, we will also see how Humean libertarianism can answer them. Humean libertarianism will turn out to be a non-valerian event-causal view of free will that holds that PAP is satisfied by the absence of necessity with a vengeance, which renders it compatible with Humean determinism, but incompatible

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with determinism with a vengeance. Also, we will see in chapter 4.2.3 that it satisfies a notion of control which is very similar to traditional eventcausal libertarian views. For the sake of clarity, the details of Humean libertarianism will be spelt out below, so let us now discuss the problems for event-causal views.

4.1 OBJECTIONS AGAINST ALTERNATIVISM 4.1.1 THE CONSEQUENCE ARGUMENT AND THE TRUTH OF DETERMINISM The consequence argument as such is not an argument against libertarianism, but an argument for incompatibilism. So prima facie, libertarians should welcome it, as libertarianism is traditionally seen as an incompatibilist view. The argument has first been deployed by David Wiggins in 1973 and since then it has been steadily debated and improved, most notably by Peter van Inwagen.388 For this discussion, I borrow a reconstruction of the argument from one of Robert Kane’s more recent discussions of it, as his version nicely demonstrates the impact of the argument given in chapter 1 for distinguishing two types of determinism: Humean determinism and determinism with a vengeance, and, accordingly, physical necessity simpliciter and necessity with a vengeance. We will see how it can be converted into an argument not only for incompatibilism, but against libertarianism. Before we start, let us remember the above-mentioned two types of determinism and physical necessity: Humean Determinism: The world w ϵ  is Humean deterministic just in case for any w’ ϵ , if w and w' agree at any time, then they agree at all times.389 Determinism with a vengeance: The world w ϵ  is deterministic with a vengeance just in case for any w’ ϵ , if w and w’ agree at any time, then they are compelled to agree at all times by the natural laws that all the worlds in  share.

388 See Wiggins 1973, and e.g. van Inwagen 1983, 2002, 2004 . 389 Compare Earman 1986, p. 13.

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Physical necessity simpliciter: A fact is physically necessary simpliciter iff it occurs in every world that shares the same laws as the actual world. Necessity with a vengeance: A fact is necessary with a vengeance iff it is compelled by a law of nature. Before we turn to the much more technical version of the consequence argument as it is given by Peter van Inwagen, let us now for illustration purposes apply the above-mentioned distinctions to the argument as it is more easily understandable reconstructed by Robert Kane:

(1) There is nothing we can now do to change the past. (2) There is nothing we can now do to change the laws of nature. (3) There is nothing we can now do to change the past and the laws of nature. (4) If determinism is true, our present actions are necessary consequences of the past and the laws of nature. (That is, it must be the case that, given the past and the laws of nature, our present actions occur.) (5) Therefore, there is nothing we can do now to change the fact that our present actions occur.390

Obviously, in order to arrive at (5) we need the additional premise that determinism is actually true. From this, Kane arrives at the conclusion that if determinism is true, we do not have the power to do otherwise, which is a necessary condition for libertarian free will. Hence, if the consequence argument is valid and determinism true, libertarianism is false. Most of the criticism the consequence argument has provoked rested on the implication of (5) by (3) and (4), as this entailment in order to be valid requires an additional principle, the so-called “transfer of powerlessness principle”, which states that: 390 Kane 2007, p. 10 original italics.

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(TP) If there is nothing anyone can do to change X, and if Y is a necessary consequence of X (if it must be that, if X occurs, Y occurs), then there is nothing anyone can do to change Y.”391 However, some counterexamples against (TP) have been formulated that have forced defenders of the consequence argument such as Peter van Inwagen to refine (TP).392 Consequently, it is this principle that has proven to be the most controversial part of the argument, as many compatibilists attacked it by challenging the incompatibilist notion of “can”.393 An extraordinarily large number of papers and books has been produced to address this issue. Indeed, it has been argued that the debate has reached an impasse as both camps, the compatibilists and the incompatibilists, seem to have agreed upon the fact that they disagree about the meaning of “can” or “ability”.394 Another way of dealing with the argument for the compatibilists is to simply deny that the power to do otherwise is a necessary condition for free will. In my attempt at attacking the consequence argument, I will not follow these strategies for a very simple reason: both types of responses to this argument are designed to defend compatibilism. It is the very purpose of this essay to defend a version of libertarianism, so we should at any cost defend some sense of the power to do otherwise. So if we leave (TP) aside for a moment, the obvious connection to our observations regarding determinism and laws of nature lies within premise (2), and hence also (3), as well as in (4). Let’s begin with how necessitarian views of laws of nature and the resulting determinism with a vengeance deal with the fixity of the laws. According to necessitarianism, there is a straightforward sense in which our actions are the necessary consequences of the past and the laws of nature. Remember that in those accounts, laws are seen not as the regularities themselves, but as those entities that necessitate the regularities. These 391 Kane 2007, p. 11, my italics. Note that (TP) also requires that X is a necessary consequence of Y, which, if it is taken as nomological necessitation, is not warranted in a Humean worldview. 392 See e.g. van Inwagen 2002, pp. 165-167. 393 See e.g. Davidson 1973 and Vihvelin 1991. 394 For an excellent overview over the different strategies to attack and defend the consequence argument, highlighting the various versions of the transfer of powerlessness principle, see Kapitan 2002.

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laws decree, or compel, us agents to act as we do. As we are forced to act as we do and have no power to change the laws, we cannot do otherwise. So if the necessitarian view of laws of nature is correct and if determinism with a vengeance is true, we have no free will, granted that (TP) is valid. This seems to be a correct interpretation of what was intended by James’ intuitive account of determinism and what the proponents of the consequence argument tried to demonstrate. Anybody who proposes a necessitarian view of laws of nature and still wants to maintain a libertarian theory of free will has to argue that determinism with a vengeance is false. As one cannot reach for Humean determinism, one has to argue for indeterminism. One has to argue that somewhere in the course of deliberation and decision, there has to be a genuine indeterminacy. The obvious place to look for indeterminacy is the Copenhagen interpretation of quantum theory, so libertarians usually reach for quantum mechanics to secure indeterminacy. This provides a tremendous difficulty for proponents of this strand of libertarianism. Quantum effects usually happen to very small physical systems, while deliberation and decision-making require the concerted firings of quite large assemblies of neurones. So libertarians of this ilk have to give a detailed account how quantum indeterminacies that happen at a micro-level can be amplified so that whole assemblies of neurones change their behaviour. Nearly all accounts that tried to spell out theories such as Pascual Jordan’s original amplifier theory395 or Roger Penrose’s and Stuart Hameroff’s Orch-OR theory396 have been refuted or are highly unlikely ever to be confirmed.397 But how do regularity theorists fare when they try to defend the principle of alternativism? Traditionally, Humeanism has been associated with compatibilism and as libertarianism is traditionally seen as an incompatibilist theory, there has been no such animal as a Humean libertarian. But what if we apply the above-mentioned strategy to define libertarianism not as the theory that incompatibilism is true and that determinism is false, but as the theory that states that agents have the power to do otherwise, are in control of their own actions, and that these actions are rational in the sense that they are 395 See e.g. Jordan 1934 and 1938. 396 See e.g. Penrose and Hameroff 1996. 397 We will discuss these theories in chapter 4.1.3.

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done for a reason? Trivially, according to Humean determinism, all our present actions (as are all our actions simpliciter) are instances of lawful regularities. But also, according to the Humeans such as e.g. Norman Swartz, our “world does not have to be the way it is, it just is”. 398 This obviously also applies to human actions: They may be regular in the sense that they are in accord with the laws of nature, but they are not compelled by them – they are not necessary with a vengeance. So even premise (2) “There is nothing we can now do to change the laws of nature”, and thus, also premise (3) “There is nothing we can now do to change the past and the laws of nature” are questionable. Regularities can only appear to be unalterable, fixed for eternity and, in James’ words “an iron block” if we perceive them to be necessitated as in necessitarian views of laws of nature. This has been noted before by Michael Slote in 1982, but he did not further develop the idea. In his discussion of the consequence argument which, as most criticisms do, concentrated on (TP), he mentioned the idea that the consequence argument seems to presuppose a non-Humean view on laws of nature: Could it not be held that the supposition that humans lack the ability to alter, to affect, the laws that actually obtain involves a controversial theory about the nature of laws, namely, that they are not just true universal generalisations with the right sorts of predicates or systematic interrelations, but rather involve some sort of physical necessity above and beyond these other facets?399

Ultimately, Slote rejects the idea and concludes that the proposed inability to alter the laws could simply be a consequence of a general human weakness to do such a thing as altering the laws, and not the consequence of the laws’ having “(a mysterious) physical necessity”.400 Even amongst Humeans, this idea seems not to be very popular. However, some Humeans

398 Swartz 1995, p. 85. 399 Slote 1982, p. 8. 400 See Slote 1982, p. 8.

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such as Helen Beebee, Alfred Mele, and David Lewis have doubted the inalterability of the laws.401 The orthodox Humean Norman Swartz gestured in the same direction: I want to suggest that the claim in that argument – the claim that the Laws of Nature are not of our choosing – is a relic of the earlier view that Laws of Nature are God's inviolable prescriptions to the Universe. [break] If we fully abandon the view that the Laws of Nature are prescriptions, then the way is open for us to rescue the theory that Free Will exists.402

So, indeed, strange as it may sound, a Humean can accept that agents could in a sense change the laws, as those laws are nothing over and above the occurrent facts, some of which are our actions or consequences of our actions. Note that Lewis – who by the way, in best Humean tradition, was a compatibilist – proposed a weaker thesis: Lewis accepts the truth of the counterfactual claim that “I am able to do something that, if I did it, a law would have been broken.”403 How Lewis’ and Swartz’ diverging views on the ability to break the laws relate to each other will be addressed shortly below. Note also that in one sense no Humean can hold that we are able to break the laws: laws are (a subset of) generalisations that are true past, present, and future. So in that sense, agents can only have influence on what, at the end of it all, the laws are like, but they cannot falsify true propositions about past, present, and future facts. Helen Beebee and Alfred Mele developed the same idea that agents can change the laws, but in a (as is traditional for Humeans) compatibilist framework.404 Like Norman Swartz, they hold that a Humean view of laws of nature does not deprive us of the power to do otherwise, which they call “dual ability”. Consider an agent, Fred, who has to decide whether to have breakfast or skip it: 401 See Beebee and Mele 2002, and Lewis 1981. 402 Swartz 2004, internet source, original bold face type. 403 See Lewis 1981 p. 115. 404 Remember that Alfred Mele remains agnostic as to whether compatibilism or incompatibilism is true. He still holds the view, however, that there are free agents (See Mele 2006, p. 4).

154 To say that the laws are such that together with past facts they entail that Fred eats breakfast tomorrow is already to presuppose that Fred eats breakfast tomorrow; but this presupposition […] does not itself strip Fred of the ability to decide whether or not to skip breakfast and act accordingly. […]. On a Humean conception of laws, just as facts about the future do not deprive us of present dual ability, facts about what laws there are do not deprive us of such ability either, since the relevant feature of laws just is the fact that part of what laws describe is the future. Thus a Humean – unlike van Inwagen – can reject the general claim that ‘if P is a law of nature, then no one can render P false’ ([van Inwagen] 1983, p.63).405

Conveniently, Beebee and Mele rephrased their critique of the consequence argument in order to clarify it, which leads us, rather inconveniently, to a problem that Humean defenders of free will have to face. Beebee and Mele propose to scrutinise a possible worlds analysis of the power to do otherwise. The natural way to test whether one has the power to do otherwise is to test whether there is a possible world in which the agent does otherwise. Consider Fred and his breakfast decision again. The dispute between the defenders of the consequence argument and Beebee and Mele, so they claim, seems to be about the question which class of possible worlds is the one that Fred’s ability to have breakfast should be tested against. Beebee and Mele hold that it should only be worlds with the same past as the actual world, while the defenders of the consequence argument propose the additional restriction that the worlds also have the same laws.406 With their rejection of that additional premise, Beebee and Mele are on firm Humean ground: to a Humean, the past does not compel the future, and the laws are (a subset of) the regularities that hold at the end of time. So why restrict the class of worlds against which to test the claim that Fed has the power to skip breakfast to those worlds that do not only share the same past as the actual world, but also the same regularities? If determinism is true, then there is only one possible world that shares the same past and laws as the actual world: the actual world. The notion that two possible worlds have the same past and still in one Fred decides to have breakfast and in the other he does not is the starting point of the argument from luck, which we will discuss in chapter 4.2.1. 405 Beebee and Mele 2002, pp. 207-208, original italics, apart from “P”. 406 See Beebee and Mele 2002, p. 209.

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As noted above, Beebee and Mele clearly adhere to the traditional notion of compatibilism. But I would like to demonstrate in this essay that a strong, libertarian account of free will is incompatible with determinism with a vengeance, but compatible with Humean determinism. So the default notion of libertarianism as an incompatibilist thesis does not fully capture what I take to be the true core of libertarianism: that free agents have the power to do otherwise and act for a reason. But the question of how to construe libertarianism is independent from the fact that I can, and do, accept Beebee’s and Mele’s original way of attacking the consequence argument. To sharpen this view, let us return to premise (4) of the consequence argument: “If determinism is true, our present actions are necessary consequences of the past and the laws of nature. (That is, it must be the case that, given the past and the laws of nature, our present actions occur.).” All depends on how it is interpreted that something is a necessary consequence of a law of nature and what it means that our actions must occur. To repeat, if Humean determinism is true, then our actions are instances of strict regularities, but they are not compelled by some mysterious force. However, the intuition that they are compelled seems to be what is behind the consequence argument, at least in the way Robert Kane reconstructs it, when he clarifies premise (4) with the addition of “it must be the case that, […], our present actions occur.” Unfortunately, most proponents of the consequence argument never explicitly state what theory of laws of nature they propose and hence, whether they propose necessity with a vengeance, and likewise, if they endorse Humean determinism or determinism with a vengeance. But the way the consequence argument is presented hints towards a necessitarian reading. Peter van Inwagen’s way or presenting the consequence argument may be a bit more careful than Kane’s, but is ultimately in accord with the way Kane reproduced it. In order to be valid the argument rests on two inference principles:

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α ⎕p ⊦ Np β Np, N(p⊃q) ⊦ Nq.407 Read Np as “p and no one has or ever had any choice about whether p”. Thus, β is the above-mentioned transfer of powerlessness principle. Further, read “L” to be the conjunction of all the actual laws, “P0” to be a proposition that describes the entire state of the world in the remote past, and “P” as any true proposition. So here comes the argument: (1) ⎕((P0 & L) ⊃ P) (2) ⎕(P0 ⊃ [L ⊃ P])

1, standard logic

(3) N(P0 ⊃ [L ⊃ P])

2, α

(4) NP0

Premise

(5) N(L ⊃ P)

3,4,β

(6) NL

Premise

(7) NP

5,6,β.408

As you can see, van Inwagen also utilises the same crucial premises that we discussed above for Kane’s more accessible version of this argument: β is (TP), which is quite controversial – a fact that we will ignore here for reasons stated above, van Inwagen’s premise 1 is Kane’s premise (4), and van Inwagen’s premise (6) is Kane’s premise (2). So the same criticism against Kane’s premise (2) also applies to van Inwagen’s argument: is it really true that we cannot break the laws? As you can see from (1), van Inwagen also takes any true proposition about our world to be a necessary consequence of the laws of nature and some remote past state of the universe. Here it is open just how strong “⎕” is intended by van Inwagen: he 407 Van Inwagen 2002, p. 159. Please note also that van Inwagen holds that β is false in the way it is presented here and takes great care in reformulating it in van Inwagen 2002, pp 160-167. More on that in a short while. 408 Van Inwagen 2002, p. 159 my italics.

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takes the box to express necessity in the sense of truth in all possible worlds. Van Inwagen does not explicitly state whether he really means all possible worlds, or just all physically possible worlds. Here the same questions apply as for Kane’s premise with its strong modal talk (4) “If determinism is true, our present actions are necessary consequences of the past and the laws of nature. (That is, it must be the case that, given the past and the laws of nature, our present actions occur.)”. But, fortunately, our argument does not rest solely on the way Robert Kane presents premise (4). As seen above, van Inwagen’s version is much less outspoken in this regard.409 But nevertheless, whether Kane and van Inwagen or the other proponents actually do differ how they spell out this premise and how outspoken they are with regard to what kind of necessity and laws of nature they propose makes no difference for the question whether the argument is valid, as for the Humean, Kane’s premise (2), and respectively van Inwagen’s premise (6), are invalid anyway. As at least premise (2)/(6) is invalid, so is the overall conclusion that we cannot do otherwise. We may reconstruct the power to do otherwise, which was the very criterion for libertarian views the consequence argument was turned against by hard determinists, then as follows: Power to do otherwise = At the moment of decision t there exist at least two real alternatives h and h’, neither of which is necessary with a vengeance and the agent has the power to cause either of them. We are now at the very heart of the argument that this entire book consists of: that a libertarian view of free will that honours the criteria of alternativism (or the power to do otherwise, respectively) and control can be reconciled with a Humean worldview, even with a Humean understanding of determinism. This definition of the power to do otherwise is deliberately formulated to be unspecific as to which theory of causation to back it up with. This is to not exclude any theory of causation compatible with Humean supervenience as discussed in chapter 2.2. It has to be noted, though, that however the agent decides and acts, in order to be free, there must be a cause for the agent’s decision and action, and this cause needs to be a reason in order to satisfy the criterion of control. So whatever 409 See also van Inwagen 1983, p. 16.

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alternative the agent brings about, if this alternative is not caused by a reason-state then the action which demarcates that alternative is not free; a merely haphazard popping up of alternatives is not sufficient for freedom. We will return to the problem of control in chapter 4.2. Finally, after having seen van Inwagen’s formulation of the consequence argument, we can now consider David Lewis’ account of the freedom to break the laws and pit it against Beebee’s and Mele’s. As a Humean, Lewis was sympathetic to attacking the premise of the consequence argument that states that we are not able to break the laws. However, he approaches the task in a different way. Lewis sets out to defend compatibilism, although he does not hold that determinism is true.410 Lewis holds that, assuming that determinism was true – which, in Lewis’ view, it is not – we could still act freely even if our actions were determined by the laws and by past states of the world. Like Beebee and Mele, Lewis claims that we actually do have the power to break the laws. But, importantly, Lewis distinguishes between a weak and a strong sense in which we are able to break the laws: (Weak Thesis) I am able to do something such that, if i did it, a law would be broken. (Strong Thesis)I am able to break a law.411 Lewis is adamant that the weak thesis does not amount to say that something could be both a law and broken. As in Lewis’ view laws have to be unbroken regularities in order to become axioms or theorems of the best deductive systems, it would be contradictory to speak of a broken law. If a regularity is broken it cannot be a law. So his view that it is possible that a free agent’s action can be such that if he did it, a law would be broken, amounts to the thesis that the according regularity would be broken and hence would fail to be a law; it would, in Lewis’ words, at best be an “almost-law”.412 That is one reason why Lewis rejects the strong thesis: It

410 See Lewis 1981, p. 113. 411 Lewis 1981, p 115. 412 See Lewis 1981, p. 114.

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is plainly impossible to convert a law, which is a regularity that is unbroken past, present, and future, into a broken regularity. Our power to break the laws is merely counterfactual in Lewis’ view. The other reason why Lewis rejects the strong view is that in one sense it is extraordinarily incredible to him that we could break the laws. According to Lewis, we cannot break the laws in the sense that e.g. we can throw a stone so hard that it accelerates past the speed of light, or that our hand in throwing the stone itself moves faster than light. Lewis holds that in this sense, our actions can neither cause law-breaking events nor be law-breaking events themselves. So in order to ensure our counterfactual law-breaking power that is humbler than the unbelievable power to accelerate our hands beyond the speed of light, Lewis holds that we are able to do something that, if we did it, somewhere in the past before the action a small lawbreaking event, a “divergence miracle”, happened which was causally relevant for the divergent course of action.413 Lewis holds that we should not think of the action as to have caused the divergence miracle, as that would imply backwards causation. By postulating the divergence miracle Lewis circumvents the obvious objection that if we are able to break the laws with our actions, why then does it seem so counterintuitive to hold that we could accelerate a stone beyond the speed of light? In Lewis’ account, neither is there any law-breaking event that is caused by human action nor is any human action ever a law-breaking event as it would be the case in the stone-throwing example. The only counterlegal event is the divergence miracle that is no causal consequence of any action. At first sight it seems as though the occurrence of the divergence miracle would counterfactually depend on whether or not the divergent action (the action that, if it occurred, a law would be broken) occurs, in which case Lewis on his own account on causation would have to accept that the divergent action caused the temporally preceding divergence miracle, which would be a case of backwards causation. But Lewis denies that the divergence miracle counterfactually depends on the divergent action, as the divergent action only entails that some divergence miracle has occurred, but not that a particular divergence miracle has occurred. Hence, the occurrence of a particular divergence miracle does not counterfactually depend on the occurrence of 413 See Lewis 1981, pp. 116-117.

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a particular divergent action. Neither does the non-appearance of the divergence miracle counterfactually depend on the non-occurrence of the divergent action, as the divergence miracle might still have occurred, but could have been cancelled out by a second divergence miracle.414 Peter van Inwagen responded to this argument in 2004, but did not focus on Lewis’ charge against the premise that no one could ever break the laws, but on Lewis’ claim that the original argument by van Inwagen is allegedly circular.415 Van Inwagen goes on to modify the argument in order to remove the alleged circularity, but does not further discuss Lewis’ attacks on the crucial premise about our ability to break the laws. Van Inwagen suggests that this reflects a genuine philosophical dissent that he did not try to resolve by a knock-down argument,416 and that he is simply not willing to pay the price for compatibilism by accepting that free agents are able to render the laws of nature false: Well, [Lewis] would certainly have rejected one of [the consequence argument’s] premises. He would certainly have rejected this premise: “No one could possibly have this ability [to break the laws].” Well and good: if he doesn’t believe it, he doesn’t believe it and the obvious thing for him to do is to say so.417

This result would not be very satisfactory, and luckily van Inwagen does indeed discuss why he is not willing to pay the price of rejecting the premise that no one is able to change the laws. He invokes a scenario in which it would be completely absurd to state that someone is able to change the laws: consider Elijah, who is in Jerusalem and tries to convince his audience that he is able to be in Babylon in ten minutes time, which he cannot because the laws of nature in conjunction with the past entail that he cannot reach Babylon in ten minutes without performing a miracle. To perform such a miracle is entirely implausible to van Inwagen. Hence he 414 See Lewis 1981, pp. 117-118. 415 See Lewis 1981, p. 120. 416 See van Inwagen 2004, p. 348. 417 Van Inwagen 2004, p. 347, original italics. Remember that both van Inwagen as well as Lewis are concerned with compatibilism and hence pay no attention to libertarianism.

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invokes the same difficulty that is already mentioned above: if Lewis (or I) want to claim that we are able to break the laws (in some sense), then we have to accept that we have the ability to perform even such extraordinary miracles such as moving faster than the speed of light. So van Inwagen, without trying to present a knock-down argument, just raised the price for accepting the view that free agents are able to break the laws by making this even more implausible.418 And although Lewis defused this attack to a certain extent by proposing that not the action or their consequences themselves break the laws, but a small divergence miracle in the past which is causally relevant for the action, van Inwagen’s attack hits Beebee’s, Mele’s, (my,) and Swartz’ proposals with full force. So how does Lewis’ view relate to the one proposed in this essay and how shall we deal with the seemingly implausible consequence of our view that it entails that we are also able to break such sacrosanct laws such as the second law of thermodynamics? Lewis’ account seems to be much humbler than Beebee’s and Mele’s (and mine) in the respect that he does not have to claim that any action could ever cause or be a law-breaking event, while this seems to be a consequence of my account. In any form of Humeanism, the laws supervene on the facts, it is not the case that the laws exist prior to the events or could even pose some sort of resistance against counterlegal facts. But does that imply that I am committed to the view that, if I tried hard enough, I could throw a stone that consequently moved faster than the speed of light? My answer is this: so far, we have reason to believe that material objects do never exceed the speed of light. Thus, I have every reason to believe that I will never accelerate any material object to that kind of speed. But what exactly does it mean that we have “every reason to believe” that some event – be it an action or even the will or will not occur? This sounds as though I, secretly, still adhere to the idea that there is something in the world – the laws – which regulates what will come to pass and what will not. But this is not the case. It is the same old question that regularity theorists of all time have had to answer ever since Hume’s dilemma: How, if the laws are just patterns in occurrent facts and do not govern what the world is like, are we justified to infer inductively? I

418 See van Inwagen 2004, p. 350.

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will not try to answer the problem of induction here, but it has to be noted that the charge that Humeans have no good reason to expect the future resemble the past is nothing but the problem of induction. Likewise, our actions may be regular and in accordance with the laws that hold for neurological systems, and hence, we expect people to behave in accordance with past regularities. But still, from a Humean point of view, it seems absurd to think that the laws prohibit any different behaviour, just as it would be absurd to think that the laws prohibit superluminal movement. People behave in accordance to the relevant regularities and stones never exceed the speed of light. That is just the way the world is. But neither people nor stones are forced to behave as they do. We have seen in the chapters 1.3.1 that indeterminism, if there even is indeterminism in our world, happens at a micro level. Current neuroscience suggests that the neural mechanisms that are behind consciousness in general and decision in particular are best described by deterministic laws.419 Humeans are not committed to the view that these regularities have to change in the future or that they have changed in the past. However, to repeat, the are committed to the view that these deterministic laws are contingent. The future does not have to behave as the past did. So to return to the question of what to prefer, Lewis’ take on the fragility of laws or Beebee‘s and Mele’s, I do not try to present a thorough refutation of Lewis’ take on the freedom to break the laws. But, as we have seen, Beebee’s and Mele’s take on this matter is much less demanding. It does not depend on a particular theory of counterfactuals, and, more importantly, it does not depend on the possibility of divergence miracles. As a result, I favour Beebee’s and Mele’s more simple view. Before we wrap up, it is necessary to remark that there are three similar approaches available in the literature that did not find their way into the account so far. The reason for this is that these accounts, while pursuing a similar goal of reconciling libertarianism with determinism, argue quite differently than Beebee, Mele, and Lewis. the respective authors are Thomas Buchheim, Kadri Vihvelin, and Geert Keil.420 Let’s give a quick 419 At least, we will see in the following chapter that the most prominent attempts at locating indeterministic processes in the brain have failed. 420 See e.g. Buchheim 2004 and 2006, Vihvelin 2000, and Keil 2007.

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overview of how these authors’ views differ from the one proposed here and consequently, why their accounts will not expand any further into this essay. Thomas Buchheim takes determinism in a similar vein as Humean determinism is presented here, but he offers no explicit argument for it or against a necessitarian reading, other than his confession that he, for lack of knowledge of the debate about natural laws, abstains from judgement whether a governing law view is correct.421 He takes his abstention as sufficient to establish a non-governing view of determinism, which it is not. Likewise he takes the necessitation relation in van Inwagen’s consequence argument as logical necessity, which he (correctly) identifies as powerless when it comes to necessitating physical events.422 Despite the lack of argument and precision, the view does not depart too much from ours yet. Most importantly amongst other points of demarcation between Buchheim’s view and the one proposed here, Buchheim suggests a sort of modest agent-causation, which we have rejected. Similar to Randolph Clarke’s idea, Buchheim postulates that actions are caused by the agent as a whole, not by some physical part of her, but he holds that reason-states can still be causally relevant for the action.423 Again, Buchheim offers neither argument nor further clarification how this might be possible. All in all, Buchheim’s proposal will not act as a model for the further course of this essay. Kadri Vihvelin’s much more carefully presented account rests upon the view that when we judge whether an agent was free in the sense that she could have done otherwise, there are two ways of making that counterfactual judgement. One way would be to hold the laws fixed and see whether there are worlds which have the same laws as ours and in which the agent does otherwise. Vihvelin argues that if we test the ability to do otherwise by means of a counterfactual which we test by holding the laws fixed, it turns out that no agent ever has the power to do otherwise.424 But if we judge the power to do otherwise by holding the past fixed instead of the laws, a different picture emerges in which there are possible worlds in which the agent does otherwise but the laws are different. In these worlds, Vihvelin argues contra Lewis, who holds that the divergence miracle must 421 422 423 424

See Buchheim 2004, p. 48. See Buchheim 2006, p. 108. See Buchheim 2004, pp. 59-60, and 2006, p. 170. See Vihvelin 2000, pp. 153-155.

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have happened in the more remote past, the choice of the agent would be the divergent miracle.425 So far, Vihvelin’s view fits nicely into our argument. But in the end, she tries to defend herself against the argument that she cannot on this ground exclude such extraordinary powers such as walking on water and moving beyond the speed of light. She argues that when evaluating whether an agent had the power to do otherwise, we have to consider the agent’s capabilities. What the agent is capable of, however, is fixed by the laws of nature.426 However, we should not accept this. If we accept that we can judge a person to be able to do otherwise because there are possible worlds in which the agent does otherwise and which share the same past, but in which the agent’s choice is a divergence miracle which changes the laws, how can we know that the laws that are changed are not the ones that define the agent’s capabilities? In short, we cannot say that the agent is free to break the laws but only in the boundaries of the laws. Geert Keil argues in a very similar vein as Beebee, Mele, and Lewis. Keil also holds that a Humean understanding of laws of nature sustains a notion of PAP as we have discussed above. He also holds that a theory of laws of nature which complies with Humean supervenience of some form is inconsistent with the premise of the consequence argument which states that agents do not have the power to change the laws. Moreover, he holds that the theory of natural laws one proposes has an influence on what kind of determinism one can propose. A Humean view on natural laws cannot sustain a necessitarian view of determinism which holds that the facts are fixed or compelled. So far, his argument is completely in accord with the general argument of this essay. However, Keil builds from this an ability-based view of freedom which is different from the one put forward in this essay.427 I do not offer any arguments against his view on freedom, just as I do not offer conclusive arguments against most other accounts of freedom The sole purpose of this essay is to outline a Humean libertarianism, and not to defend it against all other views on the market. Keil’s proposal

425 See Vihvelin 2000, pp. 155-156. 426 See Vihvelin 2000, p. 159. 427 See Keil 2007, pp. 123-128 for his arguments concerning laws of nature an PAP, and pp. 130-136 for his ability-based view of freedom.

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is kindred to Humean libertarianism as proposed here, but a detailed discussion of it should be left for further research, since it is not necessary in the context of this essay.

To wrap up, We have seen that a chief argument for incompatibilism and against free will does depend on the theory of laws of nature that one proposes. With a Humean background, one can escape an argument against libertarianism that bases on the consequence argument. So a Humean can hold that an agent has the power to do otherwise: If an agent is not necessitated, not compelled, to behave as she does, then she has the possibility to act otherwise, even if, in a humble, Humean sense, her action was an instance of a lawful regularity. In a Humean view, regularities are contingent features of our world, and in that sense, there is nothing that keeps agents from influencing them. Any Humean is bound to the claim that the laws supervene on the occurrent facts: it is facts in, laws out. It is the facts that determine what the laws are and not the laws that govern what the facts will be. No Humean can hold the view that laws in some way govern the facts – to hold a view such as this means leaving the Humean team. So why would it be offensive for a Humean to think that our actions, which are nothing but occurrent facts, determine what the laws are? Nevertheless, let us adopt more careful vocabulary. The classical discussion centred around the question whether we could change the laws. And to repeat, strictly speaking, even in a Humean worldview, we cannot: A law is true past, present, and future. No action can falsify a proposition that is true past, present and future. But our actions, qua occurrent facts, determine what, at the end of it all, counts as a law. So our actions do not change the laws, they determine what the laws will be. On a related note, this does not entail that our actions are irregular, or haphazard: as David Hume famously pointed out, our everyday action, and even our survival, relies upon the fact that our actions and those of the people around us are regular.428 We simply assume that a sane person responds to social interaction as we expect them to do: when you ask a question in a philosophical seminar you expect your students to try to answer the question or look away inconspicuously. You certainly would not expect one of them to bite off 428 See Hume, Enquiry, section IX, 1.

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your head. In fact, you rely on the assumption that sane, well-informed, well-behaved people that are of sound mind and disposing memory will act regularly. So if you define libertarianism as I did above, i.e. as a theory that requires the truth of the principles of alternativism and control, libertarianism can be construed as a compatibilist theory. Libertarianism as reconstructed here is compatible with Humean determinism and incompatible with determinism with a vengeance. At this stage, a libertarian, or indeed any incompatibilist, could, and probably will, argue that this humble sense of the principle of alternativism and the power to do otherwise does not suffice and that free actions must not even be instances of strict, but powerless regularities which are not yet settled. But then libertarianism becomes all the more ambitious: you have to give a detailed account on how exactly the neuronal processes involved in decision-making can be indeterministic and then, on a different note, show how the agent then regains control over these actions. These problems will be addressed in chapter 4.2. Humean libertarianism may seem as a weaker theory of libertarianism in contrast to the garden variety libertarian theories. But as we will see from the problems they spark, Humean libertarianism might be the best you can hope for.

4.1.2 FRANKFURT-STYLE CASES In his seminal 1969 article, Harry Frankfurt designed a thought experiment that still have a huge influence on the debate about free will. This thought experiment was originally designed to show that the principle of alternative possibilities, i.e. the claim that for an action to be free, there have to be at least two alternatives to act, is false. Importantly, Frankfurt originally designed this argument to show the falsity of the principle of alternative possibilities as a prerequisite for moral responsibility. But it can be taken to also falsify that this principle is a prerequisite of libertarian freedom. Michael McKenna and David Widerker e.g. hold that the traditional view is that PAP is a necessary condition for freedom, and since freedom is a necessary condition for responsibility, so is PAP.429 Since the 429 See McKenna & Widerker 20032, pp. 2-3.

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publication of the original article, a vast and intricate debate about Frankfurt-style cases has emerged, which constantly produces new variations of the original thought experiment in order to accommodate arguments upon counter-arguments.430 We can leave it open here whether Frankfurt-style cases actually succeed and falsify traditional libertarianism, but we have to investigate whether they pose a threat for Humean libertarianism. After all, Frankfurt-style cases have been designed to show that the principle of alternative possibilities, which is one of the defining characteristics of Humean libertarianism, is false. The Frankfurt-style cases also apply to compatibilist notions of the power to do otherwise. Originally, Harry Frankfurt formulated his thought experiment as a refutation of PAP as a condition for moral responsibility. But unfortunately, it not always clear what the participants of the debate about Frankfurt-style cases talk about: freedom or responsibility. Laura Ekstrom for example discusses the Frankfurt-style cases in great detail in the context of moral responsibility, only to conclude that they fail to demonstrate that freedom does not require PAP.431 In fact it does not matter whether the Frankfurt-style cases are designed with responsibility or freedom in mind, since, given that PAP is a condition to libertarian views of freedom as well as responsibility, the thought experiments can be adapted to either subject by simply replacing “responsibility” with “freedom” or vice versa. While the Frankfurt-style cases can be directed against PAP as a necessary condition both for freedom and for responsibility, most of the counter-arguments focus heavily on moral responsibility with all its ethical implications, so it is difficult to adapt them to our purposes. As I have done throughout the paper and will continue to do, I will ignore the debate about responsibility and concentrate on freedom instead. Let us consider a Frankfurt-style example of John Martin Fischer’s design that is particularly prominent in the current debate. There is an agent, Jones, who is in a polling booth and is about to decide who to vote 430 For a good overview over the recent developments of the debate, see the various articles in Widerker and McKenna 20031, as well as their introduction to the anthology. Most of the depiction of the state of the debate in this text rests upon McKenna’s and Widerker’s excellent volume. 431 See Ekstrom 2002, p. 321.

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for: Bush or Gore. However, a liberal neurosurgeon called Black, who wants Jones to vote for Gore, has implanted a device in Jones’ head. This device monitors Jones’ brain activity and if Jones is about to vote for Bush, the device makes Jones’ to vote for Gore. If Jones votes for Gore on his own, the device does not interfere. Black installed this device in a way that it remains undetected by Jones. For his very own reasons, Jones decides to vote for Gore so that the device implanted by Black does not have to intervene. Intuitively, we would consider this to be a free action, but Jones clearly did not have alternative possibilities open before him, although for him it might have felt that way. Had he been about to decide to act against Black’s will, Black would have forced him to decide to vote for Gore. So there are at least some actions that are free and yet still the agent does not have the power to do otherwise.432 Several versions of the argument are available, created to refute various counterexamples. One popular way of countering the argument is to say that there must be some prior signs that the agent is about to decide contrary to the intervener’s plan, and that these “flickers of freedom” are sufficient for establishing alternatives. Hence, the agent could have done otherwise.433 Another response to Frankfurt-style cases which rely on a prior sign is given by David Widerker, who holds that the prior sign that appoints whether the intervener shall interact or not must either be a reliable sign for the agent’s action, in which case it determines the action, or it is not a reliable sign and causes the action only indeterministically. This response thus comes as a dilemma: either the sign is a deterministic cause, then the action done on the agent’s own accord is not free, or the prior sign is an indeterministic cause, but then the agent could have done otherwise. Either way, the Frankfurt-style argument fails.434 To counter this argument, the thought experiment has been modified in such a way that there are no prior signs which trigger the intervention. One popular version of this modification of the thought-experiment is given by Alfred Mele and David Robb. In their version of the argument, Black installed a deterministic process which brings about the desired action if the agent does not indetermin432 See Fischer 2002, p. 282. 433 The classic flickers of freedom response was given by Peter van Inwagen (See van Inwagen 1983). 434 See Widerker 2003.

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istically cause it by himself. In such a case, the deterministic process does not rely on prior signs.435 Another popular way of modifying the argument is to propose that Black interferes with Jones’ head in the way that he blocks all or all of the relevant alternatives to act such that the only way Jones can act is the way that Black wants him to. These examples also do not require prior signs.436 At first glance, the Frankfurt-style cases seem to be intuitively plausible. John Martin Fischer, an outspoken defender of the argument, states its intuitive plausibility as follows: I do not know how to prove the irrelevance thesis [the thesis that alternative possibilities are irrelevant to free will], but I find it extremely plausible intuitively. When Louis Armstrong was asked for the definition of jazz, he allegedly said, “if you have to ask, you ain’t never gonna know.” I am inclined to say the same thing here: if you have to ask how the Frankfurt-type cases show the irrelevance of alternative possibilities to moral responsibility, “you ain’t never gonna know.”437

Despite this allegedly obvious plausibility, there is a vast discussion about the Frankfurt-style cases. On principle, there are two possible ways to respond to the Frankfurt-style cases. Opponents of the Frankfurt-style cases could either argue that the agent indeed has the power to do otherwise in these examples, or they could argue that she is not free or morally responsible when she acts on her own. For the sake of brevity, I will only sketch what I take to be the most promising argument for the second line of response that is designed to show that the agent is not free or morally responsible when she acts on her own according to the plan of the controller, given by Robert Kane. Kane argues that even in elaborate Frankfurt-style cases which require no prior signs, the agent is not free and responsible for what she does if she acts on her own. The most prominent types of Frankfurt-style cases which require no prior signs contain either blockage or preemption. In cases of blockage, all (or all relevant) alternatives to act are blocked by (a process implemented by) the intervener, so that the agent can only opt for one way to act. If she does so on her own, 435 See e.g. Mele and Robb 1998, 2003, and Mele 2006, pp. 81-104. 436 See Hunt 2000 and 2003. 437 Fischer 2002, p. 292, original italics.

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she will not realise that the other alternatives are blocked. The most famous preemption case is Mele’s and Robb’s above-mentioned argument in which the intervener installed a deterministic process into the agent’s brain which will bring about the action that the intervener wants the agent to perform. Only if the agent acts on her own as the intervener desires, the process is preempted. Kane argues that in both kinds of arguments,438 if the agent acted on her own, she was not responsible for her action, because it was deterministically brought about by the intervener. Kane does not accept Mele’s and Robb’s claim that the deterministic process does in no way interfere with the action if the agent acts on her own as the intervener wants her to. Kane maintains that the process serves to prevent all (relevant) alternatives, and hence is causally relevant for the action. Kane maintains that the process together with the agent’s beliefs and desires deterministically bring about the action. But if the action is deterministically brought about, the standard libertarian should not accept this as a free, responsible action.439 In fact, as Bernard Borofsky points out, we could construe the implanted deterministic process and the agent’s own indeterministic process which leads to the decision as overdetermining the decision. But if the agent is overdetermined to act as the intervener wants her to, she cannot be free.440 This demonstrates why responses such as this are difficult to adapt to our program at hand. In Humean libertarianism, we distinguish between two types of determinism and hold that only one of them is incompatible with libertarianism. So for the Humean libertarian, it is of no avail to show that the agent is not free or morally responsible because her action is brought about deterministically. This leaves us with the second line of response, i.e. to show that the agent could indeed have done otherwise. Let us remember our definition of alternative: Alternative = A possible development of the world h and another possible development of the world h' are real alternatives at time t, iff h and h' have an identical content until t and a mutually different content after t. 438 In fact Kane construes the Mele/Robb-argument to be a blockage argument (See Kane 2003, pp. 94-95). 439 See Kane 2003, pp. 96-103. 440 See Berofsky 2003, pp. 118-119.

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The world in which Jones is about to act contrary to Black’s plan, so that Black intervenes, is an alternative in the strict sense to the world in which Jones decides on his own to act according to Black’s will. However the Frankfurt-style case is formulated, Jones’ overt action has different causes in both alternative worlds. In the world in which Jones acts on his own it is his own set of reasons to act which cause his decision or action, and in the world in which Black intervenes, the cause of the decision or action is a process initiated by Black. These worlds are alternatives in the strict sense, and Jones has the power to cause either. Hence, the Frankfurt-stye examples do not violate PAP and PPDO as it is defined here: Power to do otherwise = At the moment of decision t there exist at least two real alternatives h and h', neither of which is necessary with a vengeance and the agent has the power to cause either of them. In his defence of what he calls “daring soft libertarianism”, Alfred Mele argues for a similar response to the Frankfurt-style examples. Mele holds that in cases such as these, the agent has alternatives open before her: while the future is not open in the sense that she might decide and act contrary to the will of the intervener, the future is open nonetheless to the effect that she might bring about a world in which the intervener forces her to act unfreely. Because this alternative does not contain a free, controlled action, this alternative is merely nonrobust. If the agent could choose between at least two free actions, she would have robust alternatives open before her. The world in which the agent is about to decide otherwise, which decision is intercepted by the intervener’s machinery, is an alternative in the strict sense because it is different to the actual world, even if the decision and the action turn out the same. The agent has the power to bring about this alternative, although she might not even consciously notice the difference between acting on her own and acting because of the controller’s intervention.441 Mele holds that the agent in such Frankfurt-style scenarios is only in a weaker sense free: When and only when an agent freely A-s at a time at which he has at least a nonrobust alternative possibility, the action is *basically free.442 441 See Mele 2006, p. 115, original italics. 442 Mele 2006, p. 115. This notion of *basically free actions is a component of

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This has to be distinguished from basically free actions, for which it is a necessary condition that the agent had at least a robust alternative open before her.443 Mele holds that in many traditional libertarian accounts, it is a necessary condition not only that there are alternatives possibilities, but also that in these alternative possibilities are robust in the sense that all alternative actions are controlled, free actions. Robert Kane e.g. holds that for self-forming actions, the alternatives must contain free, controlled actions. The requirement that all relevant alternative actions must be free, controlled actions is the so-called “plurality condition.”444 Mele holds that to these accounts, the Frankfurt-style cases provide a counterexample, because in these cases, the alternative the agent has open before her is not robust enough to fulfil e.g. Kane’s plurality condition.445 The notion of *basically free actions is very illuminating: In the case of Frankfurt-style examples, there are at least two possible actions, one of which is free and the other is not. Mele concludes that for an action to be *basically free, the alternative action need not be free.446 This insight is particularly illuminating for the Humean libertarian, as in his view, even in a Humean deterministic universe the agent has at the time of decision the power to do otherwise than she actually does, as the laws do not prescribe a future course of events. But this alternative which lies open before the agent might just be a world in which his reason-states fail to cause the desired action and she does something else, something undesired, instead. This possible action clearly would not be free, as it would not be caused by an according reason-state. Nevertheless, it is an alternative in the sense discussed in the above chapter and hence the actual action, the one in which the agent did act according to her reason-states, was free. At this stage it is possible to object that this notion of alternative and the power to do otherwise is too wide: what the original Frankfurt-style examples were designed to show is that Jones could perform only one overt action, or that was only able to decide one way. But why should we Mele’s daring soft libertarianism, to which we will turn in greater detail in chapter 4.2.1.2. 443 See Mele 2006, p. 114. 444 See e.g. Kane 2007, p. 32. 445 See Mele 2003. p. 252-253. 446 See Mele 2006, p. 124.

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accept such a narrow view? Why should we restrict the relevant alternatives to only the ones which contain different overt actions or different conscious decisions? Why would one want to preclude worlds which are different from the actual and which are caused by the agent as relevant alternatives? There is independent reason to hold that PAP should not be interpreted in a way that the alternative has to contain a different overt action or decision: In simple cases of free actions, the alternative might be not to do anything different, but simply not to act. And this condition is met in the case of Frankfurt-style examples: if Jones is about to decide contrary to Black’s will and Black intervenes, Jones’ decision and his subsequent behaviour is a consequence not of Jones’, but of Black’s beliefs and desires, so it could be argued that it is not even an action at all, at least not Jones’. So in this sense, in Frankfurt-style cases, Jones has the ability to do otherwise even in a narrower sense: he has the ability to act or not to act at all. Still, there is another, more direct way to reject the Frankfurt-style as a Humean libertarian. In a Humean sense, Jones has the power to do otherwise regardless of whether the sense of alternative discussed above is too wide in order to be legible for PAP. As discussed in great length above in the context of the consequence argument, even if the world turns out to be deterministic, there is a sense in which an agent can always do otherwise: the laws of nature do not compel Jones to act in any particular way, since they do not compel anybody or anything to do anything at all. This entails that the process which Black starts in order to cause Jones to act as he, Black, pleases, does not prohibit any behaviour of Jones’, as well as any other physical fact does not compel Jones to do anything or forcefully prevent him from doing anything. If Jones’ action is not necessary with a vengeance, there is a sense in which Jones could have done otherwise, and neither Humean determinism nor Black can make Jones’ action necessary with a vengeance. If this Humean take on the power to do otherwise was conclusive in my discussion of the consequence argument above, it is conclusive here as well. But let us not be too hasty here. If this argument is correct, you might object, is it not the case that Jones could have done otherwise even if he did not decide on his own to vote for Gore, but caused by the device

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implanted by Black? If so, would we have to conclude that Jones was free even if he did not decide on his own? Clearly, this would be extremely counterintuitive. I agree that this consequence would in fact refute my proposal to solve the argument. But to conclude that Jones is free even if Black intervenes is to forget that PAP is not the only condition for freedom; Jones also has to be in control of his own actions. As we will discuss at greater length in chapter 4.2, an agent is in control of her own actions if her actions are caused by her own beliefs and desires. Because Jones’ action is not the effect of his own beliefs and desires in the case of Black’s intervention, he cannot be free, regardless of whether there is a sense in which PAP was satisfied. To conclude, to adopt the very same Humean libertarian strategy against the Frankfurt-style cases as against the consequence argument yields exactly the result we are looking for: If Jones decides on his own to vote for Gore, his action is free, because he is in control of his action in the sense that his own beliefs and desires cause it, and he is not forced to behave otherwise and could even bring about a different alternative in the strict sense. If, however, Black’s device intervenes, Jones’ action turns out to be unfree, not because his action is necessary with a vengeance (which it is not), but because Jones has no control over his action. We will turn to the problems surrounding the notion of control in the following chapter.

4.1.3 ALTERNATIVE POSSIBILITIES AND MODERN SCIENCE The Humean libertarianism proposed in this essay differs from garden variety types of libertarianism in a very important respect: as the weak sense of the power to do otherwise defended above is independent of the truth of determinism, the Humean libertarian fortunately does not have to show that indeterminism is true and how exactly indeterministic events in the brain can be both causally relevant for free actions and still under the control of the agent. This is a serious advantage, as up to this day no plausible theory of how indeterministic micro-physical events can be causally relevant for free actions and still be under the control of the agent has been empirically sustained. All of the proposals that will be discussed in this subchapter are empirically refutable, as they make claims about the phys-

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ical nature of the decision processes.447 For illustration, let us take a look at four major theories to this effect: Pascual Jordan’s original amplifier theory, Roger Penrose’s and Stuart Hameroff’s Orch-OR-theory, the most prominent contemporary event-causal libertarian theory which is Robert Kane’s libertarianism, and lastly, Mark Balaguer’s libertarian proposal.448 What all of these theories have in common is that they are designed to show that and how indeterministic microphysical quantum mechanical events can have effects on a macroscopic scale, i.e. on the firing patterns of rather large conglomerations of neurones. Theories to this effect are commonly called “amplifier” theories. Other proponents of some version of amplifier theory include such illustrious figures as John Searle, Karl Popper and John Eccles.449

4.1.3.1 JORDAN, PENROSE, AND HAMEROFF Let us first discuss Pascual Jordan’s classical amplifier theory. Jordan’s original theory was heavily influenced by the advent of quantum theory in the early 20th century. As we have already noted, quantum effects take place in microphysics,450 and decisions involve large assemblies of neurones. So in order to claim that decisions are not physically determined because of indeterministic microphysical quantum effects, some additional thesis has to be employed to show that these quantum processes have causal effects on the macrophysical level, or, more precisely, whether the macroscopical processes that govern our behaviour are controlled by indeterministic quantum effects.451 To claim that microphysical processes control the processes that account for our behaviour goes well beyond the more modest claim that incidentally, every once in a while a microphysical 447 A fact that was first noted by Pascual Jordan (see Jordan 1938, p. 537). 448 All four of these theories are event-causal. The existing agent-causal libertarian theories that require physical indeterminism in the brain will be ignored from now on as we have already rejected agent-causation in chapter 3.2. 449 See e.g. Searle 2007, pp. 74-76. and Popper and Eccles 1977. 450 Although, as Anton Zeilinger’s experiments with fullerene molecules suggest, there seems to be no principle restriction to the size of physical systems that can exhibit quantum mechanical effects. (See Arndt et al. 1999, pp. 680-682) 451 See Jordan 1938, p. 537

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process has a macroscopic effect. Obviously, as organisms such as humans are ultimately build from the littlest particles, it would be quite absurd to say that none of these particles does at times exhibit quantum effects. The crucial question is whether these effects get lost at the macro level or whether they have such stringent influence on the macrolevel that they can be said to control it. Jordan phrases the central problem as the question whether human beings are essentially macroscopical objects. If they are, then quantum processes have no systematic causal influence on the macro level. Jordan’s central claim is then that human beings are not essentially macroscopic objects.452 Jordan lists a number of microphysical processes that have an influence on the organism as a whole to prove his thesis. In his 1938 article Die Verstärkertheorie der Organismen in ihrem gegenwärtigen Stand he cites for example the effects that α-radiation has on a cellular level. According to Jordan, if an assembly of cells is bombarded with α-radiation, the cells do not react uniformly to the same level of radiation: some cells die sooner, some later, some survive. This difference cannot, as Jordan claims, be accounted for by the biological diversity among the cells, but by indeterministic microphysical effects of the radiation itself. Moreover, he claims that even one single impact of α-radiation can kill a cell. Jordan takes the fact that such a small-scale event as the impact of a single particle can kill a comparatively large-scale object like a cell as evidence for his amplifier theory.453 Most of the criticism against Jordan hinges on the fact that the evidence he lists in defence serves more to disprove his theory than to back it. Among the first who mentioned this peculiar fact was the biologist Erwin Bünning, who stated that the whole lot of Jordan’s examples of amplification are instances of quantum effects that are entirely irrelevant to decisionmaking. Moreover, most of Jordan’s examples such as the one given above are instances where, while doubtlessly there is a causal influence of microphysical events on biological organisms, these events are quite often lethal. Bünning goes on to claim that biological organisms whose successful operation depended on indeterministic quantum effects would be prone to spon-

452 See Jordan 1938, p. 538. 453 See Jordan 1938, p. 540.

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taneous death.454 As a consequence, the successful operation of biological processes depends on the fact that Jordan is wrong; would he be right, organisms would be susceptible to spontaneous death.455 Moreover, Bünning bemoans that most of Jordan’s arguments, as the one given above, concern extraneous influences on biological organisms, which are completely independent of the internal biological control mechanisms that could account for human action.456 Nowadays, Bünning’s criticism is widely accepted,457 so we need not follow the case any further. What Jordan’s failure demonstrates, however, is that any libertarian theory that lends its indeterminism from quantum physics needs to elaborate a lot more on the physical aspects of decision-making and on where exactly quantum effects come into effect there. The two most elaborate theses to this effect available today are Penrose’s and Hameroff’s Orch-OR-theory (Orchestrated Objective Reduction) and Robert Kane’s libertarian theory. Roger Penrose and Stuart Hameroff (P&H) avoid Jordan’s mistake of not investigating neuronal processes that are actually relevant for human decision-making. Like Jordan, however, they rely on quantum mechanics to secure indeterminism.458 Penrose and Hameroff are perfectly aware that in order to have a regular, systematic relevance to decision-making, quantum processes have not only occasionally to occur within the brain, but need to be a built-in part of regular decision processes. They are also aware that in order to explain human decision-making, they need to give an elaborate theory of how large assemblies of neurones can be simultaneously causally influenced by quantum processes. In order to achieve this goal, they perceive the human brain as a kind of quantum computer. Their theory is designed to be not merely a theory of free will, but to be a detailed neurophilosophical theory of consciousness in general. Penrose and Hameroff, before collaborating, started their respective investigations with the phenomena of seemingly non-algorithmic processing of 454 See Bünning 1935, p. 339. 455 See Bünning 1935, p. 346. 456 See Bünning 1943, p. 196. 457 See e.g. Walter 1999, pp. 196-197, although he complains about Bünning’s often careless and imprecise way of presenting his arguments. 458 As we will see, the indeterminism they propose is epistemic, not ontological.

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mathematic problems in the human mind (Penrose)459 and the mode of action of anaesthetics (Hameroff).460 To explain both types of phenomena, P&H located the relevant mechanisms in the microtubules of neurones, where they suspect that certain quantum processes take place, which we will discuss below. Microtubules are hollow cellular structures that form a kind of cellular skeleton. Before Penrose’s and Hameroff’s individual theories, these microtubules were not perceived as relevant to consciousness at all, and even nowadays, P&H have not convinced a majority of neuroscientists that microtubules actually do fulfil any crucial role for it.461 P&H have to deal with the same problem as Jordan: they have to give an explanation of how microphysical quantum phenomena can serve as a systematic control function for macrophenomena such as decision-making. In short, P&H’s theory holds that information processing is physically represented by quantum phenomena within the microtubules of neurones. Whenever the quantum states collapse, a solution is reached. According to P&H, the collapse takes the form of an orchestrated objective reduction. We will turn to what that means in a short while. First of all, P&H have to make the claim plausible that there even are sustainable quantum processes within the microtubules. As we will see, their theory requires that it is possible that there are quantum states within a large number of neurones, each of which contains roughly 107 tubulins (those subunits of microtubules in which the quantum effects are supposed to occur), of which at least 1000 are needed for an orchestrated objective reduction, which is the proposed quantum phenomenon that represents problem-solving and decision-making (we will se below what an orchestrated objective reduction is supposed to be). The faster the information processing needs to be, the more tubulins have to be involved, about 109 for a processing time of 500 msec.462 The quantum states have thus to be 459 See e.g. Penrose 1994. 460 See e.g. Hameroff 1994. 461 See e.g. Tegmark’s work who has shown that even if the microtubules could be in a state of superposition, the brain cannot sustain states of superposition for long enough so that they could have an influence on conscious decision-making (see Tegmark 2000). 462 For a concise overview over the physical and biological aspects of P&H’s theory discussed in this chapter, see Penrose and Hameroff 1995, pp. 102-104.

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sustained over a quite long period of time and, even more ambitious, have to be orchestrated in the sense that these quantum states collapse simultaneously in a large number neurones (hence Orch-…, we will turn to the …OR later). As we have seen in chapter 1.3.1.1, the wave function collapses when the physical system which is in a quantum state interacts with another physical system. Thus, P&H require an environment in which quantum processes, which in their theory are the basis of consciousness, are not disturbed. For this, they postulate that the microtubules are filled with ordered water463 and that the relevant quantum phenomena take place only in the dendrites, where there are no intracellular ions such as chloride which would disturb the ordering of water.464 P&H postulate (and it is nothing but a postulate) that within these microtubules of larger assemblies of neurones, there are physical systems which are simultaneously in quantum states. For this odd homogeneous behaviour some explanation needs to be given. The most likely candidate for an explanation for the supposed homogeneous behaviour of quantum systems within the microtubules of larger functional units within our brain is that the physical systems that are in quantum states are mass-entangled.465 These mass-entangled states (if it is mass-entanglement) according to P&H can be construed as parallel processing of information, thus the quantum states within the microtubules implement neurophysical functions. They remain in their quantum state while an agent deliberates and they collapse when he reaches a decision. As noted above, the collapse, or reduction of the wave-function, has to happen simultaneously within the microtubules of the cells that form a functional unit. According to quantum gravity, this simultaneous collapse is induced by the mass-distribution of the individual quantum states of the 463 Ordered water is dynamically coupled to the surface of the protein that the microtubules consist of. 464 See Walter 1999, p. 203. Walter holds that the presence of chlorides in the water in fact does prohibit the ordering of it and that hence quantum phenomena could not be sustained in the neuronal microtubules. P&H admit that chloride ions would disturb water ordering, but maintain that too few chloride ions are present in neurones to effectively halt water-ordering (see Penrose and Hameroff 1995, p. 107). 465 Unfortunately, however, P&H originally gave no explanation at all for the homogeneous behaviour of hundreds of superposed quantum systems, they did not even mention entanglement (Grush and Churchland 1995, p. 26). This, as we will see, turns out to be one of the major flaws of their account.

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tubulins. When this mass-distribution reaches a certain threshold, the complex mass-entangled quantum state within all the involved microtubules self-collapses (or, in other words, is objectively reduced, hence …OR).466 This view of the human decision and deliberation mechanisms as some kind of quantum computer is meant to account for some phenomena of human deliberation. Remember that Penrose’s original starting point was the question how humans solve certain mathematical puzzles. Granting Gödel’s incompleteness theorem, Penrose holds that certain information processing techniques are non-algorithmic, which is what Penrose needs quantum mechanics for. That a process is non-algorithmic means that there is no algorithm which would make the outcome of that process predictable or computable. But information processing techniques also must not be random, as that would not be compatible with the fact that these calculations are often successful. That is why Penrose introduces the yet unconfirmed theory of quantum gravity, which (only possibly, as P&H admit) gives an account of the self-collapse or objective reduction of the wave function as something which happens neither randomly, nor computably, nor predictably.467 Hence, P&H’s indeterminism is merely epistemic in the sense of principal non-predictability, or non-computability. P&H’s theory has provoked a lot of criticism for several reasons, of which we will concentrate only on the most important. My criticism of P&H’s theory is based mostly on a seminal article by Rick Grush and Patricia Churchland.468 Firstly, it is highly speculative. There is no empirical evidence that microtubules even contain ordered water, without which the described sustainable quantum states would be impossible due to the many interacting factors which would permanently force a collapse of the wave function, which is the reason why these are not observed on a macro level. Hence, there is no evidence that the supposed quantum effects even actually take place in our brain, and if they are not present in our brain, they cannot be responsible for consciousness in general and decision in particular.469 466 467 468 469

See Penrose and Hameroff 1995, pp. 102-104. See Penrose and Hameroff 1995, pp. 98 and 102-103. See Grush and Churchland 1995. See Grush and Churchland 1995, p. 23.

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Secondly, P&H need an auxiliary hypothesis that can explain how the quantum states within the ordered water in the microtubules of a larger assembly of neurones can be simultaneous and homogenous. This most probably would be mass-entanglement, but P&H offer no explanation why these quantum processes in hundreds of neurones should be entangled and how this entanglement could come about.470 Thirdly, they also need an auxiliary hypothesis that explains how the reduction of the wave function which serves as the solution to deliberation or problem-solving processes could be self-induced. This self-collapse or objective reduction is what Penrose suspects accounts for the non-algorithmic information processing whose results are neither computable nor random. The auxiliary hypothesis to account for this self-induced collapse is quantum gravity, which as yet is neither completed nor empirically sustained, but also, as it is still in statu nascendi, is not yet empirically refuted.471 Fourthly, even if the empirical and theoretical work that yet needs to be done will some day be done, P&H have still not shown that the postulated quantum phenomena in the microtubules have even a function for consciousness in general or decision-making in particular. P&H offer no specific mechanism that could explain how an orchestrated reduction of wave functions within the dendrites of cortical neurones could be the physical representation of a decision. They do give a speculative story on how quantum processes in the microtubules of dendrites might be orchestrated, but not how this actually influences, or even constitutes, conscious phenomena which are otherwise perceived as being grounded in firing-patterns of neuronal assemblies. That is, P&H have to give an account of how microtubules can encode, process, and pass on information, which is a process usually linked to neurotransmitter activities. And if the microtubules are to have an influence on neurotransmitter activity, how exactly might that work?472 Merely postulating that microtubules are crucial for neurotransmitter transport within the neurones473 does not constitute an answer 470 471 472 473

See Grush and Churchland 1995, p. 26. See Walter 1999, p. 201. See Grush and Churchland 1995, p. 26. As P&H do in Penrose and Hameroff 1995, pp. 105-106.

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as to how exactly quantum effects within the microtubules influence firing patterns of neurones in a way that would influence consciousness. As a consequence, the Orch-OR-theory is not particularly popular.474 It is not impossible that it might be empirically confirmed one day, but as yet the situation is not very promising. Grush and Churchland sum up their feelings towards the Orch-OR-theory in the following way: To avoid standing in shadowy places, we wish to state at the outset that in our view, the argument [for the Orch-OR-theory] consists of merest possibility piled upon merest possibility teetering upon a tippy foundation of “might-be-for-all-weknow’s” […] Our assessment is not that the Penrose hypothesis is demonstrably false […]. Neurobiology is simply not far enough along to rule out the Penrose possibility by virtue of having a well established, well tested, neurobiological explanation in hand. Rather, we judge it to be completely unconvincing and probably false.475

Even 16 years on, the general consensus does not seem to have changed in respect of the plausibility of the Orch-OR-theory and so we leave it at that.

4.1.3.2 KANE In contrast to P&H, Robert Kane does not even attempt at presenting a detailed neuronal mechanism for decision-making in his libertarian theory of free will.476 As we have seen above from the shortcomings of the OrchOR-theory, this might be an advantage. Still, some of the claims he makes are empirically testable. Kane, in contrast to most other libertarians, allows that some free actions are determined, as long as these actions are the causal consequences of beliefs and desires that were formed and shaped in what Kane calls self-forming actions, or SFAs for short. In contrast to everyday decisions, an SFA is closer to what an orthodox libertarian takes any free action to be: a controlled action done for a reason which is a dis474 See e.g. Vargas 2007, pp. 143-144. 475 Grush and Churchland 1995, p. 12. 476 Kane develops his theory in greatest detail in Kane 1996 and 2007.

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play of the agent’s power to do otherwise. According to Kane, these SFAs contribute to the character of the agent in the way that they shape the agent’s beliefs and desires which in turn causally influence (or even determine) future free actions.477 To cut a long story short: Kane does not have to show how each and every free action might be a display of the agent’s power to do otherwise, but only how SFAs can be caused in such a way that immediately prior to decision, there actually existed at least two possible worlds in which the mutually incompatible alternative actions are realised and the agent had the power to cause either of them. Kane holds that any SFA is a consequence of a genuine struggle to decide for a suitable course of action. Some actions, Kane holds, are so decisive that they partly determine similar future actions by shaping the agent’s character. In cases such as these, there exist at least two mutually incompatible sets of motivational states, each of which could cause one of the alternative courses of action. These incompatible sets of motivational states rival for being acted upon, and which set prevails is a matter of indeterminism. Kane further coins the concept of ultimate responsibility. He holds that free agents must be ultimately responsible for their actions in the sense that the agents themselves contributed to the beliefs and desires they hold.478 This is exactly what happens in SFAs. If there had not been real alternatives when the agent performed an action which formed her character, then the agent would in no meaningful sense be responsible for her character and her future actions, Kane maintains.479 Let’s consider an example. Sarah has to decide whether to go to college and study particle physics or to become a goldsmith. Let’s assume for the sake of simplicity that Sarah holds a couple of relevant beliefs and desires, amongst which are the desire to understand the foundations of our universe and the (correct) belief that she has the cognitive capacity and the endurance to complete her studies and become a good physicist. On the other hand, Sarah likes jewellery and has the desire to create beautiful things from precious metals. She has the desire to exercise craftsmanship and the belief that she has the capacity to become a very good goldsmith. The 477 See Kane 1996, p. 75 and 2007, p. 15. In earlier texts, Kane refers to SFAs also as “self-forming willings” (see e.g. Kane 1996, p. 125). 478 See Kane 2007, p. 14. 479 See Kane 1996, p. 77 and 2007, p. 22.

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unusually gifted Sarah also holds the belief that she can only complete one job training: either particle physicist or goldsmith. Hence, she has to form a decision, which is the result of a deep and long struggle. Kane holds that struggles such as these have to have their neuronal correlates, and that the underlying neuronal process in indeterminate in outcome. Kane envisages the following mechanism: before the will of an agent is set in an SFA, she struggles with the decision to perform a couple of alternative actions, all of which she has reasons to perform. In the case above where the agent had two possible alternative courses of action, she had two sets of reasons to act which were neuronally represented in the brain. The struggle the agent feels is not an illusion, but the perception of her brain’s parallelly processing both sets of reasons.480 Which one of these sets of reasons or neuronal processes prevails is a matter of indeterminism, which in Kane’s theory is taken as an obstacle that the agent has to overcome. If an agent has two alternative courses of action, both alternative sets of motivation are represented each in a neuronal network which acts upon the other. If both sets of motivations are equally strong, the parallel processing of the two becomes a chaotic process in the sense that a very small change can lead to macroscopic changes. As long as the neuronal conflict between the competing networks remains undecided, i.e., as long as the two alternative sets of reasons are equally strong, the brain is in a “thermodynamic equilibrium”, as Kane calls it: The two networks are connected so that the indeterminism that is an obstacle to her making one of the choices is present because of her simultaneous conflicting desire to make the other choice – the indeterminism thus arising from a tension-creating conflict in the will, as we said. This conflict, as noted earlier, would be reflected in appropriate regions of the brain by movement away from thermodynamic equilibrium. The result would be a stirring up of chaos in the neuronal networks involved.481

480 See Kane 2007, pp. 26-28. 481 Kane 2007, p. 28.

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Kane holds that as the resulting chaos is being “stirred up” by the sustained deliberation over the competing sets of motivations in such a conflict, quantum effects become relevant for decision-making, as they provide the small changes that chaos magnifies to influence the decision.482 Accordingly, Kane’s account is a modern take on the classical amplifier theory. A decision is reached when a quantum event ends the thermodynamic equilibrium and causes one of the competing neuronal networks to prevail, which Kane takes as to overcome the obstacle which is the indeterminism built in into to the process. Thus the indeterminism fulfils an interesting role in Kane’s account. It does not only serve as a way of securing the power to do otherwise, but he also interprets it in a way as to answer the common criticism regarding control. If a set of motivations to act prevails in such a scenario of inner struggle, it not only prevails over a competing set of motivations, but also over the indeterminism. The agent does not act because of the indeterminism in her brain, but despite it. What Kane has to make plausible then (apart from the claim that the brain is indeed a chaotic system) is that the choice which is based on an indeterministic quantum event in the brain is indeed under her control, that it is her decision. Kane answers this objection by stating that the agent still acts for her own reasons, it is her genuine own motivation which causes her action and which prevails over the other reasons to act. Agents have control over their actions, since they, as Kane puts it, “will have succeeded in doing what they were knowingly and willingly trying to do.”483 We will turn to this account’s implications for the problem of control later, as its defence will turn out useful for Humean libertarianism. but for now let’s focus on the empirical implications of Kane’s theory. As to this matter, Kane, although presenting a theory more sensitive to the philosophical problems of the free will debate than for example Pascual Jordan’s, fares no better than Jordan or Penrose & Hameroff. There is yet no empirical evidence that decision-making is indeed a chaotic process that can be influenced by quantum effects, or that a deep inner struggle is represented 482 See Kane 2007, p. 29 an 1996, p. 130. 483 Kane 2007, p. 30.

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by parallel processing. If Kane’s claims to this effect will ever be empirically refuted, his account has to be withdrawn however original and philosophically clever his solutions to the problems of PAP and control are.

4.1.3.3 BALAGUER Mark Balaguer has very recently proposed an event-causal libertarian account similar to Robert Kane’s.484 Balaguer holds that it is very much possible that we are free in a libertarian sense. He concentrates his analysis on what he calls “torn decisions”: according to Balaguer, a decision is torn if an agent has to decide between two or more alternatives for which she has equally good reasons. In the end, she just acts one way, without being convinced that the action she performs is the better alternative - she just acts. In contrast to Kane, these decisions are not always character-building. Some of these decisions may be as mundane as to choose which dessert to order. Balaguer holds that these torn decisions may turn out to be indeterministically caused, but he does not propose a theory as speculative as Robert Kane’s to back this claim.485 Balaguer holds that in order to be free decisions, these torn decisions must not be completely random, but have to be appropriately nonrandom. A decision is appropriately nonrandom in Balaguer’s view if it is authored and controlled by the agent and if the agent has plural control over the action, i.e. that however the agent acts, the action is authored and controlled by the agent.486 Balaguer proposes the following conditions for authorship and control: (A&C) An agent A has authorship and control with respect to a torn decision D if, but not necessarily only if, (i) A makes D in a conscious, intentional, purposeful way (i.e., D is an A-consciously-choosing event); (ii) A’s choice flows out of her conscious reasons and thought in a non-deterministically causal way; and (iii) once

484 See Balaguer 2004 and 2010. That Balaguer proposes this event-causal libertarianism does not entail that he endorses it. Balaguer holds that the truth or falsity of this libertarianism is a yet undecided empirical question (see Balaguer 2010, p. 69). 485 See Balaguer 2010, pp. 71-75. 486 See Balaguer 2010, p. 84.

187 A moves into a torn state and is going to make a torn decision, nothing external to her conscious reasons and thought has any causal influence over which options she chooses.487

If an agent at some points in his life makes decisions that are undetermined and authored and controlled by the agent, and in fact Balaguer holds that torn decisions are very common, then the agent is free. Balaguer holds that torn decisions are not the only decisions that can be free. It is also e.g. possible that sometimes the agent has no reasons for both options altogether – the choice just would not matter. Moreover, some decisions might be such that although they are undetermined, the agent might lean towards one of the alternative ways of acting. And most importantly, even actions that are completely determined can be free, if the agent had clear and determining reasons to act. For this, however, the agent must be a free agent, i.e. some of his decisions must be undetermined, and the supposedly free determined decision in question has to be authored and controlled by the agent.488 Although Robert Kane also allowed some free decisions to be determined, there is one big difference to be noted here: in Kane’s case, the free determined actions have to be causal consequences of the agent’s character which he formed in undetermined decisions – the SFAs–, whereas in Balaguer’s view, it suffices that some actions are undetermined, which do not necessarily have to contribute to the agent’s character. So in Balaguer’s view, not all our decisions have to be undetermined to be free, but if we someday should find out that none are undetermined, then we are not free in a libertarian sense.489 As noted above, Balaguer’s view is less speculative than many other libertarian theories on the market. Balaguer neither proposes an elaborate neuronal mechanism as Kane does, and nor does he make any bold claims about the ontological nature of the agent. In fact, he

487 Balaguer 2010, pp. 87-88, original italics. 488 See Balaguer 2010, pp. 122-123. For this, authorship and control obviously have to be defined in a different way as for torn decisions, i.e. without reference to undetermined processes. 489 See Balaguer 2010, p. 125.

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proposes a token-token physicalism and maintains that the reasons for which agents act are purposeful, conscious, intentional mental events which are identical to the appropriate physical neuronal events.490 Although Balaguer’s theory is less speculative as the above-mentioned, it nevertheless requires that the physical processes that constitute our decisions are undetermined. Balaguer holds that Kane’s theory makes so many empirically testable assumptions that it is quite unlikely that it may turn out true in all its details.491 But this criticism not entirely fair. At least, Kane does give an account on how it could actually be the case that the neuronal processes which constitute our free decisions are undetermined, whereas Balaguer simply claims that they have to be undetermined in the particular way he proposes in order to be free, and whether and how exactly that might be the case is an open scientific question. However, Balaguer’s hesitation to make any wildly speculative claims makes his theory probably the most likely libertarian theory to be true. Moreover, as we will see in the following chapter, Balaguer offers very helpful criticism of the argument from luck and establishes a notion of control that is very applicable to our purposes. Let us wrap up. Granted, the accounts presented in this paragraph are highly ingenious and original. But all of them make empirically testable claims about the neuronal nature of decision-making which are yet to be confirmed. All of the accounts rely upon quantum indeterminacy to secure the power to do otherwise. Only one of these accounts, the Orch-OR-account, presents a detailed mechanism how this might work. But unfortunately, doing so makes the Orch-OR-theory all the more implausible for reasons which we have discussed above. The other three theories, Jordan’s, Kane’s, and most of all, Balaguer’s, remain to a varying degree silent about the actual mechanism of decision and thus avoid immediate refutation, but they do propose that the brain, or at least the areas which are relevant to decision-making, is an indeterministic system, or that, in case of Kane’s account, a chaos can be “stirred up” by competing incompatible motivations to act. It would be unfair to criticise Jordan, P&H, Balaguer, and Kane for presenting theories that are empirically testable. It is to their great 490 See Balaguer 2010. p. 85. 491 See Balaguer 2010, p. 70.

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credit that they try to reconcile libertarianism with modern science. But unfortunately, all their accounts have as yet resisted empirical confirmation. As Grush and Churchland put it: “Given what is known, “very remote” is the label typically stamped on the possibility that quantum mechanical effects play any explanatorily significant role in neuronal function.”492 The Humean account on alternativism and the power to do otherwise presented in this chapter is able to present us with this core requirement of libertarianism without relying on abundant metaphysics or bold empirical claims. Let’s see how a Humean view of libertarianism can answer the problem of control and if it fares any better or worse than its main rivals in this respect.

4.2 OBJECTIONS AGAINST CONTROL AND A HUMEAN SOLUTION We have seen above that for an action to be free in a libertarian sense, it not only has to satisfy PAP and PPDO, but it must also be under the control of the agent. Whether an action is under the control of the agent is determined by the relation between the agent’s reason-states and the action. Moreover, control requires that the agent’s reason-states have the right sort of causal history. If both requirements are met, we can speak of an action as being under the control of an agent and being rationally explicable, i.e. intelligible. Since we already rejected noncausal and agent-causal views, we do not have to consider their respective definitions of control. This leaves us with two of the varieties of control noted in the introduction: Proximal Control = An agent has proximal control over her actions iff her actions are caused by her beliefs and desires. Ultimate Control = An agent has ultimate control over her actions iff they are caused by her beliefs and desires and these beliefs and desires were chosen by the agent. We will discuss these two definitions of control alongside the arguments against event-causal libertarian views that are aimed to show that the agent has no control over her actions. We will discuss two influential 492 See Grush and Churchland 1995, p. 10.

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arguments against control here: the argument from luck and the argument based on Benjamin Libet’s famous experiment. The consequence argument, which is often construed as an argument that demonstrates that if determinism is true, we have no control over our actions because we lack the power to do otherwise, does not have to be repeated here, since traditional libertarians reject the premise that determinism is true, and the Humean libertarian can reject the premise that there is nothing we can do now to change the laws. For the argument from luck, things are not as easy for the Humean libertarian. As Helen Beebee and Alfred Mele have pointed out, a Humean conception of alternativism and the power to do otherwise puts the Humean in the same uneasy position which standard libertarian theories are in: both have to answer the argument from luck. Roughly, the argument from luck goes as follows: if free actions are the consequences of indeterministic events, then how an agent acts is a matter of luck. And if an action is a matter of luck, then it is neither under the control of the agent nor rationally explicable. As a consequence, the argument from luck is an argument against the principle of control as well as against the demand that a free action has to be intelligible, i.e. rationally explicable.493 This chapter will consist of 3 parts. At first we will take a look at three of the most prominent event-causal libertarian defences of control against the argument from luck, then I will turn to an argument that rests upon the famous experiment by Benjamin Libet which, again, is an argument against the principle of control, because it is taken to show that reason-states are causally ineffective. After this, we will take a look at how a Humean libertarian might try to solve the problem from luck and what sense of control can be retained.

4.2.1 THE ARGUMENT FROM LUCK AND SELECTED RESPONSES To understand why Humean libertarianism faces the problem of luck, let us discuss it more carefully. Remember the Humean’s take on the power to do otherwise: Since the laws of nature supervene on the occurrent facts, of which some are our actions, the laws are in fact not fixed until the world 493 Randolph Clarke has come to the same conclusion regarding the argument from luck (See Clarke 2003, pp. 80-82).

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actually ends. To a Humean, our actions, just as all occurrent events, determine what the laws are like. Hence our actions cannot be compelled by the laws of nature. Roughly, the argument from luck states that if two possible worlds are exactly alike until some time where an agent makes a decision, and if it is possible that in the one world the agent acts one way and in the second world the other way, then it is a matter of luck how the agent acts, because there is no difference between the two worlds until the moment of decision that can account for the difference between the two worlds afterwards. As the argument is designed against classical incompatibilist theories, the argument and the response to it have to be modified in order to fit the Humean view proposed here. Whereas in standard libertarian accounts an indeterministic process accounts for the chanciness of action, it is the absence of determinism with a vengeance that accords for the openness of our actions in Humean libertarianism. The basic problem remains the same: if a possible world in which an agent does A and one in which she does not-A at t are alike until t, what is it in these worlds that accounts for the cross-world difference after t? Amongst the authors who propose a Humean view of the power to do otherwise, Alfred Mele is the one who most thoroughly discusses the argument from luck from a libertarian perspective.494 We will consider his exposition of the problem and the two possible solutions he proposes in greater detail below. However, I am convinced (and I try to demonstrate) that Robert Kane’s and Mark Balaguer’s answers to the argument from luck are more helpful than Mele’s and can be modified to fit Humean libertarianism. We will, however, see that Kane’s account of ultimate control, which he calls “ultimate responsibility”495 is problematic. I will discuss only the solutions to the argument from luck by Mele, Balaguer and Kane, as I hold them to be the most helpful responses available. Remember that in this essay, it is not necessary to defend Humean libertarianism against each and every other event-causal libertarian view. Humean libertarianism has its very raison d’être in the fact that determinism might actually be true, as we have seen in chapter 1. No other event-causal libertarian

494 See Mele 2006. 495 See e.g. Kane 2007, pp. 13-22 for his exposition of ultimate responsibility.

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account, except for Mele’s daring soft libertarianism, can accommodate determinism. Because of this, we only have to consider these event-causal accounts which prove to be helpful for our task at hand. Randolph Clarke tries to clarify the argument from luck with an example. Consider Peg, who has to make a decision about whether to lie or tell the truth. If she has the power to do otherwise, it is genuinely open whether she will lie or not. However she decides, she acts for a reason, for she has good reason to act out both alternatives, and her act will be caused by the appropriate reason-state. So there are two possible worlds, one in which she lies and one in which she does not. In the actual world, she decides to tell the truth. Both worlds are identical right up to the instant she decides. As there is no difference in both worlds that can account for the different further courses of these two worlds from the instant right before the decision onwards, it is a matter of luck how Peg acts. Hence, it is beyond her control.496 In Clarke’s own words: Everything prior to the decision, including everything about Peg, might have been exactly the same, and yet she might have made the alternative decision. Peg in some other possible world, or some of her counterparts, are exactly the same up to the moment of decision but decide not to tell the truth. To the extent that some occurrence is a matter of luck, the argument continues, it is not under anyone’s control. The indeterminism in the production of her decision (in comparison with an otherwise similar deterministic case, in which the indicated luck would be absent) […].497

Another popular way of representing the argument from luck goes as follows: imagine there is a God, and after an agent made an undetermined decision, God hits a replay button, rewinds the universe until a point in time shortly before the decision. This time, the agent could act differently. Suppose God hits the replay button several times, and sometimes the agent

496 There are myriads of versions of this argument around. See e.g. van Inwagen 1983 and 2002 and Haji 1999 and 2000. 497 Clarke 2003, p. 78.

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acts this way, and sometimes, she acts the other way. If that is the case, would we not say that the agent’s action is capricious and random, instead of controlled?498 Clearly, this argument is designed to refute a regular indeterministic libertarian account, which – as should be clear by now – the one proposed in this essay is not. A crucial difference has to be noted: if determinism turns out to be true, then to the Humean, both worlds do not share the same laws of nature. If Peg tells the truth in the actual world, then in a strict sense, the world in which Peg lies is not physically possible. The Humeans need not propose genuine indeterminism to secure the notion that Peg has the power to do otherwise. But unfortunately, that is nothing to become too exited about. Humeans that try to dismantle the argument by proposing that as there is no nomologically possible world in which Peg acts differently as she does in the actual world are, as Beebee and Mele correctly point out, guilty of bootstrapping. Any Humean trying to follow this strategy would be guilty of using a double standard: on the one hand the fact that the laws are not fixed before the facts is used to secure the libertarian criterion of alternativism and the power to do otherwise. So when it comes to a counter-argument where this alternativism is turned against the Humean, she cannot find an easy way out by proposing that this alternative is not nomologically possible because it features different laws of nature.499 Let us investigate the event-causal responses to the argument from luck. We have seen above that there are two basic varieties of event-causal libertarianism: valerian and non-valerian accounts. Let us start with the most prominent non-valerian event causalist, Robert Kane.

4.2.1.1 KANE Remember Kane’s view on free actions as sketched in chapter 4.1.3.2: in cases of indeterministic character-forming actions, SFAs, the agent is torn between at least two alternative courses of action. On the neurophysiological level there exist at least two parallelly processed efforts to 498 This is how van Inwagen presents the argument (see van Inwagen 2000, pp. 1415). 499 See Beebee and Mele 2002, p. 221.

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act in either way. The agent pursues both efforts until an indeterministic process tips the scale and one of these efforts prevails. A very important concept of Kane’s theory has to be noted here: the notion of ultimate responsibility, which is closely related to control. Remember that Kane allows that some, if not most, of an agent’s decisions may be deterministically brought about by the agent’s character. But Kane claims that the agent would not be responsible for her actions if her character was not formed by her SFAs which are indeterministic.500 I have repeatedly stated that I do not want to discuss responsibility in this essay because of the pitfalls of the ethical implications that concept has, but in this case, we have to consider Kane’s ultimate responsibility, because he takes it as a necessary condition for an agent to be free. In fact, the notion of ultimate responsibility is introduced by Kane so that free actions do not only satisfy alternativism and PAP, but to make sure that “the sources or origins of our actions lie “in us” rather than in something else (such as the decrees of fate, the foreordaining acts of God, or antecedent causes and laws of nature) outside us and beyond our control”.501 Accordingly, Kane takes ultimate responsibility to ensure control. In Kane’s view, an agent can only be free if her actions are consequences of her beliefs and desires, which are not imposed upon her from outside, but which the agent has formed herself. Kane holds that in order to be ultimately responsible for an action, the agent must be responsible for the causes of her actions, i.e. for her beliefs and desires, for her character. An agent can be responsible for her character if her character was formed in SFAs.502 Remember our preliminary definitions: Proximal Control = An agent has proximal control over her actions iff her actions are caused by her beliefs and desires. Ultimate Control = An agent has ultimate control over her actions iff they are caused by her beliefs and desires and these beliefs and desires were chosen by the agent.

500 See Kane 1996, p. 60. 501 Kane 2007, p. 14. 502 See Kane 2007, p. 14.

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Clearly, Kane’s notion of ultimate responsibility is sought to establish ultimate control. We have mentioned above that these notions of ultimate control face an influential argument. This argument is most clearly given by Galen Strawson, who calls it the “Basic Argument”: If it is a requirement for moral responsibility that the agent not only must decide how she acts because of her character, but also that she is responsible for her character, then she must have made intentional choices to have become the person she is. But these choices again must be grounded in her character for her to be responsible for them. This yields a regress, which entails that if the regress shall stop at some place (Kane calls SFAs “regress-stopping actions”503), then either must the agent form some of her reason-states uninformed i.e. without having good reasons to shape her character in some way, or we would have to accept that the most basic beliefs and desires of an agent are out of her control and caused by external factors. 504 As said over and over before, I will not consider moral responsibility in this essay. But the argument can be rephrased in terms of control. Indeed, Strawson held that the basic argument shows that the agent cannot be in control of her character.505 Kane acknowledges the intuitive force these regress arguments have. He holds that the regress can be stopped by an SFA, in which the beliefs and desires to chose from may be caused by factors outside the agent’s control, but the decision which of these beliefs and desires to act for is not causally determined by any external factor. Thus, Kane bites the bullet and accepts that the choice in these SFAs is not caused by the agent’s character: The only way to stop this regress is to suppose that some acts in our life histories must lack sufficient causes altogether, and hence must be undetermined, if we are to be the ultimate sources or grounds of, and hence ultimately responsible for, our own wills. These regress-stopping acts would be the “self-forming acts” or SFAs that are required by UR sometime in our lives, if we are to have free will506

503 See Kane 1996, p. 75. 504 See Strawson 1986, p. 48-50 for a classic exposition of this argument. See also Strawson 1994, pp. 18-19. 505 See Strawson 1994, p. 12. 506 Kane 2007, p. 16.

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Derk Pereboom applies the same strategy as Strawson in his critique of Kane’s ultimate responsibility. Pereboom holds that if Kane wants to show that our everyday actions are responsible because they are partly determined by our character that was formed in SFAs, why should we think that the agent is responsible for her character? In SFAs, there is no antecedent control or responsibility in the sense that the agent can control what his efforts are. Pereboom asks how responsibility is created in SFAs, if it is a conditions for responsible actions that they are determined by the character that was formed in SFAs?507 Again, the argument is couched in terms of responsibility. But it can be translated into terms of control: If everyday decisions can only be under the control of the agent if they are partly determined by his character which was formed in SFAs, how can the SFAs be under the control of the agent? This is an interesting result. Kane wanted to put forth a notion of ultimate responsibility (or control), only to concede that the very actions that should provide the agent with control over her actions were only proximally controlled, i.e. that they were indeterministically caused by the agent’s very own beliefs and desires, which do not have to be the consequences of earlier SFAs. But if Kane has to accept that the agent’s character is a result of a decision which is not determined by other beliefs and desires, these SFAs are partly a matter of luck. Derk Pereboom argues that the failure of ultimate responsibility entails that how the agent acts in SFAs then is just a matter of luck and hence not under the agent’s control.508 Kane’s answer is threefold: firstly, although luck is involved, the agent did not act by luck, but despite the “probability or chance of failure”. The agent “got lucky” in the sense that she luckily escaped the chance to fail, but that does not entail that her action was simply a matter of luck and uncontrolled.509 Secondly, the fact that some aspect of her action was indeterminate does not entail that the whole action is just a matter of luck, because the agent succeeded in the face of the possibility of indeterministic failure in doing what she tried to do all along. The elegant feature of Kane’s account is that due to the parallel processing of the incompatible 507 See Pereboom 2007, p. 49. 508 See Pereboom 2001, p. 50. 509 See Kane 2007, p. 32.

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efforts, this is true for either of the alternatives. When an agent ponders whether to do A or B, her parallelly processing both efforts to act either way ensures that she did what she was trying to do, regardless whether she does A or B. The demand that in SFAs, every possible option must be backed by a set of reason-states is the so-called “plurality condition”. Thirdly, when agents act, even if an indeterministic process is involved, they endorse the outcome and do not usually distance themselves from it. They recognise the action as being of their making.510 Kane does not jump to conclusions regarding control. The fact that indeterminism does not preclude control does not entail that it does not harm control at all. Kane admits that indeterminism diminishes control. Kane asks his reader to imagine 3 assassins with differing chances of success, which all try to shoot the prime minister. Two of the assassins suffer from nervous twitches. The chance of success for the first assassin is 50 percent, 80 percent for the second, and a 100 percent for the third, which is a “young, stud assassin” without any nervous twitches. Kane accepts that the second assassin has more control over his action than the first one, and that the third assassin is in total control. But Kane insists that all three assassins are equally responsible for killing the PM if each of them succeeds, as all three of them acted as they tried to. Kane concludes that indeterminism does diminish control, but that this is the price to pay for freedom which does come with indeterminism and hence with a lessened control. The indeterminism and the lessened control act as an obstacle that an agent must overcome in order to be free.511 This is an important result of Kane’s position. He holds that libertarianism, given that it traditionally involves indeterminism, entails diminished control, and any attempt to restore full control as in agent-causation has proven to be unconvincing: I think libertarians of free will have traditionally ignored this aspect of indeterminism. They knew indeterminism was required on their view, but assumed it could be entirely circumvented by special agencies. But hindrances and obstacles and resistance in the will are precisely what are needed for free will, which, like life itself, exists near the edge of chaos.512 510 See Kane 1996, p. 183 and 2007, pp. 32-33. 511 See Kane 2007, pp. 39-40. 512 Kane 2007, p. 39.

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To return to Strawson’s basic argument, we can see that it rests on a misunderstanding of what libertarians such as Kane want to propose. Strawson is correct in holding that it is impossible for an agent to be a causa sui. But Kane does not require this. He does not require that the options over which the agent has to decide over in SFAs are of her own choice. The reason-states the agent acts for may in SFAs be innate or the consequences of education. But which of these reason-states to act for is not determined by anything outside the agent. But, as the selection of a reason-state to act upon is an indeterministic process, it is partly a matter of luck. To wrap up, Kane’s theory has a number of weaknesses: Firstly, there is the above-mentioned worry that neuroscience may discover that the proposed parallel processing of competing incompatible efforts simply does not happen in the brains of human agents. But then Kane’s entire libertarian theory would collapse, not only his answer to the problem of luck. Secondly, there are worries whether, even without consulting neuroscience, it is plausible to suggest that an agent in SFAs actually pursues at least two incompatible efforts to act. Clarke remarks that it would be absurdly irrational for an agent to simultaneously pursue two different and mutually exclusive options.513 However, there are some lessons to be learned from Kane’s response. First and foremost, it is the insight that luck does not preclude control. It is, after all, the agent’s reason-states that cause the action in the case of rational action. The action is of her own making, despite the possibility of acting otherwise, and she endorses it. But if there are alternatives open before the agent which are not decreed by the past and the law of nature, there always remains an aspect of luck: that is the price to pay for free, unnecessitated action. Whether Kane’s view that luck actually diminishes control is acceptable will have to be discussed after we have had a look at Mark Balaguer’s event-causal libertarianism. Contrary to Kane, Balaguer does not hold that indeterminism even diminishes control.

513 See Clarke 2003, p. 88.

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4.2.1.2 MELE As noted above, Alfred Mele tries to defend libertarianism against the argument from luck. He discusses the argument in two stages. Firstly, he tries to show that what he calls “traditional libertarianism” is incoherent, and that free actions lack a complete explanation. In a second move, he discusses two suggestions how to solve the problem of luck, “modest libertarianism” and “daring soft libertarianism”. Before we discuss his argument, let us clarify some of the vocabulary Mele uses: Mele takes traditional libertarianism to be the thesis that free agents are morally responsible for their free actions and that if an action is free, both the action and the opposite of the actual action are compatible with the past and the laws of nature.514 A complete explanation in Mele’s view is a contrastive explanation why the agent did e.g. A instead of non-A.515 Lastly, a basically free action according to Mele is an action whose opposite is consistent with the actual past and the actual laws of nature. So A-ing is a basically free action if at the instance the agent A-ed, his not A-ing was compatible with the past and the laws of nature.516 Mele reconstructs the argument from luck in a similar vain as did Randolph Clarke: Traditional libertarianism states that there are what Mele calls “basically free actions”. Basically free actions require that there is a possible world with the same laws and the same past as the actual world in which the agent does not perform the actual basically free action. But there is no difference between the actual world and the possible world in which the agent did not perform the actual action that could give a contrastive explanation why the agent acted as she did and not otherwise, as these worlds are identical until the moment of decision. Hence, what the agent does is a matter of luck, and if it is a matter of luck then the agent cannot be responsible for, or in control of, what action she performs.517 But if the agent does not control what she does, then neither can she be free nor can she be responsible518 for what she does. 514 See Mele 2006, p. 4. 515 See Mele 2006, p. 70. 516 See Mele 2006, p. 6. 517 See Mele 2006. pp. 7-9 518 E.J. Coffman, whose critique of Mele’s answer to the argument from luck will be discussed below, offers a very careful reconstruction of Mele’s rendition of the argument from luck, which deviates greatly from how it is presented here. The reason

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We have to be very careful here. Contrary to his earlier work, Mele does not elaborate on the existence of alternatives in the Humean sense in his 2006 book from where I lift his treatment of the argument from luck. There he only considers the traditional dichotomy of determinism and indeterminism and presupposes the truth of necessitarianism concerning natural laws.519 Thus we cannot simply take Mele’s response to the argument from luck and apply it to Humean libertarianism. But we can take a look at his response and test whether some of its features may be applicable for a defence of Humean libertarianism against the argument from luck. Firstly, let us review the easiest way to deal with the problem of luck: Mele proposes what he calls “modest libertarianism”. In this valerian view, free actions may be deterministically caused, and hence two possible worlds in one of which the agent does A and in the other non-A at t are not identical before t. Still, some indeterminism is upheld in modest libertarianism as in this view, the indeterministic process happened at an earlier stage before the actual decision just before the action. Mele proposes that the indeterminism is located at the moment when an agent deliberates over what action she shall perform. A new belief, desire, or hypothesis may come to her mind. To a modest libertarian, this may be the result of an indeterministic process. The action itself then is deterministically caused by a belief or desire, which may have indeterministically come to the agent’s mind when she was pondering what to do.520 To shift the moment of indeterminism to some time before the decision is what marks Mele’s modest libertarianism as a valerian view. In Mele’s view, to shift the moment of indeterminism from the causing of the action to the forming of desires, beliefs, and the like which may become causally relevant for an action

for this is that Coffman places too big an emphasis on the notion of moral responsibility, but does not mention control at all in all the 5 steps of his argument. (See Coffman 2010, p. 158) Moreover, I wish to direct attention away from the notion responsibility since it is not the subject of our investigation here and concentrate on control instead. 519 See Mele 2006, p. 80, n. 23. 520 See Mele 2006, pp. 10-13.

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grants the agent control over her action. Although the agent in Mele’s view does not control which desires, beliefs, and hypotheses come to her mind, she can assess and weigh them: That a consideration is indeterministically caused to come to mind does not entail that the agent has no control over how he responds to it. Considerations that are indeterministically caused (like considerations that are deterministically caused to come to mind) are nothing more than input to deliberation.521

Laura Ekstrom offers a similar deliberative account with the difference that she focusses on the agent’s preferences. In Ekstrom’s view, an agent acts according to her preferences, which cause free actions. These preferences have to be acquired in an act of deliberation whose outcome is undetermined. To Ekstrom, free actions are those actions which are deterministically caused by a decision which in turn has been deterministically caused by the formation of a preference.522 Randolph Clarke points out that valerian libertarianism does not really solve the problem of luck, it just relocates the problem to a different point in time. If it is possible for free actions to be determined and hence it is possible to give a contrastive explanation for it because the indeterminism happened at an earlier stage in the process of forming the agent’s character, it then becomes a matter of luck what the agent’s character is like. So as the agent is not in control of her character, she is not in control of the actions that are determined by it.523 In a way, modest libertarianism simply defers the problem. Mele proposes as a second libertarian theory over and above modest libertarianism to answer the argument from luck: daring soft libertarianism.524 This theory is particularly interesting for Humean libertarianism which, as noted repeatedly above, I take to be compatible with indeterminism as well as with Humean determinism, but incompatible with 521 522 523 524

Mele 2006, p. 12. See Ekstrom 2000, pp. 106-116 and 2003. See Clarke 2003, p. 67. See Mele 2006, p. 105

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determinism with a vengeance. We could label Humean libertarianism as a kind of semi-incompatibilism.525 Similarly, Mele’s daring soft libertarianism could be called some kind of a semi-incompatibilism as well: It states that whereas libertarian intuitions lean towards the falsity of determinism, a weaker sense of freedom could even be maintained if determinism turns out to be true.526 Please note again that Mele does not distinguish between several varieties of determinism as it is done in this essay. Daring soft libertarianism contains the hypothesis that what Mele calls present luck does not preclude freedom. Present luck is the compatibility of the actual action and all the unperformed alternatives with the past and the laws of nature, which is the reason for the unavailability of a contrastive explanation why the agent performed the actual action and not any of the alternatives. But daring soft libertarianism offers a two-fold strategy: Even if our actions were not indeterministically caused, they could be free nonetheless, albeit in a weaker sense.527 To elucidate the daring soft libertarian’s response to the problem of luck, Mele firstly introduces the notion of a initiatory power which is particularly illuminating. This power to indeterministically cause actions which have no proximate deterministic causes entails that the cross-world difference between the world in which the agent performed the actual action and all the other possible worlds with the same past and laws in which she acts otherwise is just a matter of luck. In cases where this initiatory power is exercised, the proximate cause of an action is a reason to act in a certain way like a belief that it would be best to perform this very action at this very time which sustains the desire to perform it. Mele accepts that luck simply comes with that initiatory power and is there to stay.528 The important question is whether the resulting luck really precludes freedom. Note that this initiatory power Mele claims indeterministic agent have is different from the one that defenders of agent causation claim for their theory: it is no special power to exercise a special kind of causa525 I will not call it like that, as this could be mistaken to imply a kinship with John Martin Fischer’s semi-compatibilism (see e.g. Fischer 2007 or 2002 for brief recent accounts of semi-compatibilism) 526 See Mele 2006, p. 95. 527 See Mele 2006, p. 116. 528 See Mele 2006, pp. 113-114.

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tion, it is simply the ability to cause events which are not determined by the laws and the past. Obviously, this provokes the problem of luck. Mele sums up the daring soft libertarian’s response to luck as follows: Daring soft libertarians (DSLs) try to stare down the problem of present luck. They claim that present luck is entailed by an agent’s having a kind of initiatory power that they value and that its presence in a case of action does not preclude the action’s being freely performed or the agent’s being morally responsible for it. The softness of their libertarianism makes their situation less treacherous than that of conventional libertarians. Soft libertarians do not assert that free action and moral responsibility require the falsity of determinism.529

To make his position plausible, the daring soft libertarian has argue for two distinct claims: that free actions sometimes do not require indeterminism and that present luck does not undermine freedom. Mele tries to make the first claim plausible by reference to Frankfurt-type examples.530 We have discussed Mele’s defence of the Frankfurt-style examples above and need not consider it here any further than necessary to understand Mele’s position. Mele agrees with Frankfurt that the agent who decided on her own to act as the intervener wanted her to act is free in her decision. But, as we noted in chapter 4.1.2, Mele holds that in daring soft libertarianism, an agent can be free in a weaker sense, i.e. *basically free, if she has nonrobust alternatives open before her. An alternative is nonrobust if it is no free action of the agent. In daring soft libertarianism, an agent can be free if the alternative to a free action is an alternative in which she does not act freely.531 As mentioned above, Mele elsewhere defends the Frankfurt-style cases against such proposals. The reason is that for any libertarian theory such as Kane’s for example in which it is required that in cases of SFAs, the agent has to have robust alternatives in the sense that she can perform at least two alternative free and controlled actions,532 the Frankfurt-style 529 Mele 2006, p. 113 530 See Mele 2006, p. 115. This is particularly interesting in the light of Mele’s and Robb’s influential no-prior-signs version of the Frankfurt cases (See Mele and Robb 1998 and 2003). 531 See Mele 2006, pp. 113-115, and 2003, pp. 254-256. 532 See Kane 2007, p. 32.

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cases show that this condition is not fulfilled. If PAP, as in Kane’s proposal, is augmented with a plurality condition, the Frankfurt-style cases show that agents can be free even if this augmented PAP is violated.533 However, in his defence of daring soft libertarianism, Mele holds that the claim that alternatives have to be robust, as e.g. Kane proposes, requires motivation.534 The claim that luck does not undermine freedom is particularly interesting for our enterprise at hand because some aspects of it turn out to be compatible with Humean libertarianism. As noted above, Mele bites the bullet and accepts that free undetermined actions are partly a matter of luck. Mele holds like Kane535 that the agent’s character and her previous free actions play a role in decision-making by altering the probabilities of the indeterministically caused possible decisions.536 A person may for example have to decide whether to do A or B, and in the past she often decided to do A in similar circumstances. A-ing often produced favourable results, whereas her previous decisions to do B led her to regret B-ing afterwards, so the probability that she decides to do A is significantly higher than the probability to decide to do B. As her decision is undetermined, there is some luck involved, but still the decision is free. So while the cross-world difference between the worlds that contain the various alternative ways to act is a matter of luck, the agent still has some control over what action she performs: it is her character and her past experiences that alter the probability of the various possibilities to act, and ultimately, it is her conscious belief, her intention to act that brings about the action.537 As we have seen above, Robert Kane holds the similar view that indeterminism and consequently luck do not preclude freedom and responsibility.538 Mele accepts that there might be a Strawsonian regress lurking in the background: if we accept that decisions are only partly a matter of luck because the agent’s past and character shift the probabilities of the possible 533 534 535 536 537 538

See Mele 2003, pp. 252-253. See Mele 2006, p. 124. See Kane 2007, p. 14. See Mele 2006, pp. 121-122. See Mele 2006, pp. 133-134. See Kane 2007, p. 27.

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actions, what about the probabilities of these previous actions and the ones before them? What about the very first free actions? The worry is that these actions might be completely a matter of luck and controlled by the agent at all. To dispel reservations that these very first actions might not be up to the agent, Mele discusses a thought experiment of a young child whose actions are not fixed by his character, yet still we intuitively regard his actions as free and himself to be morally responsible for them. The young child called Tony has to decide whether to steal his sister’s toy or not, and, after considering how his father and his sister would react to him snatching the toy from his sister, he decides not to. Young Tony’s decision is indeterministic, so there is no complete contrastive explanation available why he did not snatch the toy from his sister as opposed to stealing it. Yet still, Mele holds that intuitively, young Tony does deserve some praise for not snatching the toy from his sister, just as he would have deserved some blame if he had done it. And if it is plausible that little Tony deserves some praise for his behaviour, why should not adults if and when they decide indeterministically deserve some praise of blame for their actions, contrary to what the argument from luck tells us? Mele uses this thought experiment to show that moral responsibility is not an all or nothing affair, but that it comes in degrees.539 The argument demonstrates that contra to Strawson, an agent can be at least partly responsible for her actions, even if she has no ultimate control over her reason-states. Note again that Mele discusses moral responsibility and not control, but, as seen above, we could take control as a prerequisite for responsibility and, given the argument from luck is successful, the absence of control as the reason for the absence of responsibility. Applied to our problem this would imply that control also comes in degrees, which has a lot intuitive plausibility. E.J. Coffman argued that Mele’s response to the argument from luck is not very convincing by Mele’s own standards. Mele spends considerable time defending the argument from luck against some counter-arguments. Coffman holds that in the light of Mele’s own defence of the argument form Luck, his own proposal to refute it falls short. Mele rejects e.g. Kane’s solution to the argument from luck. As we have seen above, Kane holds that in cases of self-forming actions, the agent tries to perform all the 539 See Mele 2006, pp. 129-133.

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alternative possibilities that are open to her. That way, the agent always does what she wants to do, regardless how she acts. Kane holds that this way, the agent can be in control of the action even if the outcome of the action is a matter of luck, because she tried to act like she does, regardless of what she does, even if what she does is a matter of luck and cannot be contrastively explained.540 Mele’s response to this is that simply wanting and endorsing how you act is not enough to establish control, if the action itself remains a matter of luck and if it is not up to you what you want to do, what your reasons, or in Kane’s case, your efforts are.541 Coffman holds that the same criticism can be levelled against the case of little Tony: Mele accepts that little Tony’s choice is undetermined and lacks a complete contrastive explanation, and it is not entirely up to Tony what he wants to do, yet still Mele holds little Tony responsible for what he does. Coffman concludes that Mele either has to drop his defence of the argument from luck or accept that he did not solve it.542 I will pick up this thread later in the discussion of Kane’s proposal. But even if Mele’s answer was convincing, unfortunately it is not possible to transfer Mele’s results to Humean libertarianism in full detail. To embrace the possibility that determinism does not preclude a weaker sense of libertarian freedom, although indeterminism seems more desirable from a libertarian perspective, clearly seems promising from a Humean libertarianist point of view. But again, we have to be careful: Mele accepts the Frankfurt-style cases and concludes that determinism does not pose a threat to freedom. As seen above, the Frankfurt-style cases are designed to show that the power to do otherwise is no prerequisite for freedom, and this clearly has great appeal to Mele who wants to leave it open whether necessitarian determinism or, as we called it, determinism with a vengeance, is true, which would entail that no agent ever has the power to do otherwise. But clearly the Humean libertarian cannot accept the possible truth of determinism with a vengeance. The solution lies within joining Mele in biting the bullet and accepting that luck is there to stay, but that luck does not necessarily preclude control. 540 See Kane 2007, pp. 32-33. 541 See Mele 2006, pp. 51-53. 542 See Coffman 2010, pp. 160-162 for details.

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4.2.1.3 BALAGUER Balaguer also discusses the argument from luck, which he represents as a “replay” or “rollback” type argument. Suppose that some of our decisions are undetermined. Suppose now that God presses a replay button and rolls back the state of the universe until shortly before an agent’s decision. If the agent now does otherwise than she did the first time, would her action not be a matter of luck? And if her action is a matter of luck, how can we consider the action as being controlled and authored by the agent?543 For ease of discussion, let’s focus on torn decisions, i.e. decisions in which the agent has equally good reasons to act either way which indeterministically cause the action. Remember Balaguer’s definition of authorship and control for torn decisions: (A&C) An agent A has authorship and control with respect to a torn decision D if, but not necessarily only if, (i) A makes D in a conscious, intentional, purposeful way (i.e., D is an A-consciously-choosing event); (ii) A’s choice flows out of her conscious reasons and thought in a non-deterministically causal way; and (iii) once A moves into a torn state and is going to make a torn decision, nothing external to her conscious reasons and thought has any causal influence over which options she chooses.544

Balaguer holds that a torn decision can be authored and controlled by the agent in this sense even if the agent in a replay of his decision might do otherwise. In fact, Balaguer holds, it would be very suspicious if every time God hits the replay button, the agent acts the same way. Then we might be inclined to think that the decision was in fact not torn after all, but that maybe some subconscious factor compelled the agent to act in a certain way. Balaguer holds that there is no tension between the agent acting differently in different replays of the decision and the fact that every time in these replays, it is the agent who authored and controlled the decision. The important factor here is that although the agent might act differently in different replays or in different possible worlds, it is the agent’s very own reasons to act which indeterministically cause her to act. Balaguer holds 543 See Balaguer 2010, p. 92. 544 Balaguer 2010, pp. 87-88, original italics.

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that while the action is nonrandom in the sense that it is caused by the agent’s reason-states, it may be random in the sense that precisely because the decision was torn, she might act differently in different replays or possible worlds. Lastly, Balaguer holds that there is no tension between there being certain fixed probabilities how the agent might act and the agent being author and controller of her own actions.545 Balaguer holds that the randomness involved in torn decisions does not even diminish control like Kane thinks luck does.546 In fact, Balaguer holds that we would have even less control if our torn decisions were not undetermined. He claims that in cases such as torn decisions, there is nothing to hope for except that it is the agent who acts, that it is her reasons which bring about the action. If torn decisions were not indeterministically caused, then this would only entail that the decision was not arbitrary and that something other than the agent’s reasons must be responsible for her action, because by definition the reasons to act in torn decisions are equally good for either option. If one of these reasons would deterministically cause the decision, then we would suspect that there must be some extra, possibly subconscious, factor that decides why this reason prevailed rather than the other, which in torn decisions must be equally good. As we have seen above, Balaguer also allows that some free decisions (not the torn ones) might be determined. But he holds that if every decision was determined, we would not have spontaneous control over our actions. But in a world in which some of our free decisions are undetermined and torn and others are clearly determined by one particular reason-state, both sorts are equally controlled and authored by the agents in the sense that it is the agents’ own reason-states which cause the action and that no external factor interfered.547 Balaguer also discusses a different kind of objection against control, the argument from alien implants. Suppose that an agent faces a torn decision between two alternatives to act, but the reasons to act either way have been implanted into the agent by a clever alien. This seems to be a counterexample to (A&C), because all of its conditions seem to be fulfilled, but still we would say that the action was not authored and controlled by the 545 See Balaguer 2010, pp. 92- 94. 546 We will turn to this in section 4.2.3. 547 See Balaguer 2010, pp. 97-99.

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agent in an appropriate way. Manipulation arguments such as these are part and parcel in the debate about compatibilism. Such arguments are designed to show that proximal control does not suffice. In these arguments usually we are asked to conceive of a clearly manipulated person who is not in control of his actions, yet analysis shows that the conditions for proximal control are met. Hence, proximal control is too weak.548 Again, most of these arguments are set in terms of moral responsibility, but again, they can be rephrased in terms of control. We will turn to these arguments in bigger detail at the end of this chapter. Balaguer’s answer to the manipulation cases is not satisfactory. He claims that the alien-implants case is no refutation of his analysis of authorship and control, because he does not try to give a conceptual analysis of authorship and control. All he cares about, Balaguer claims, are actual agents and actual torn decisions, and since no aliens implant reasonstates into actual human beings, we need not care about such cases.549 I do not think we should let Balaguer off the hook that easily, especially because I think that (A&C) is a very good conceptual analysis of authorship and control. His reluctance to discuss these cases is particularly irritating because Balaguer hints at what might be a promising answer to these fanciful counterexamples: we could maintain that in such cases as the alien-implant examples, the reasons-states that the agent acts upon are not really her reason states, but imposed on her from outside, and hence conditions ii and iii of (A&C) are violated. I will return to this strategy of refuting cases such as the alien-implant case when I will try to sum up the problem of control for the Humean libertarian in the last section of this chapter. But before I can do this, we have to discuss yet another counter-example to control. So far, we have always assumed that our decisions are caused by our reason-states. What if they are not? This is exactly the problem in the argument from Libet’s experiment.

548 See e.g. Pereboom 2001, pp. 111-115 and 2008 for the famous four-case argument and Mele 2006, pp. 188-195 and 2008, pp 280-284 for the famous zygote argument. 549 See Balaguer 2010, pp. 88-89

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4.2.2 LIBET’S EXPERIMENT In 1983, Benjamin Libet published the results of an experiment that shook the philosophical community involved in the free will debate to the core.550 Libet originally tried to defend freedom of will from the results of his own paper,551 but as a result of his experiment, both libertarianism as well as compatibilism suffered a serious blow. What unites libertarianism and compatibilism (if we leave noncausalism aside) is that both theories require that free actions need to be caused by the agent’s conscious will, or by the appropriate reason-states. It is this very bedrock of causalist libertarianism and compatibilism that many authors took Libet’s experiment to refute, while Libet himself sought to defend free will of any form by adopting a highly controversial hypothesis that we will turn to below. If Libet’s argument succeeds, we are in deep trouble. For event causal libertarian theories, it is necessary that free actions need to be caused by reason-states in order to be both under the control of the agent as well as to be rational. So if the argument succeeds, both criteria of control and rationality fall, and so does event causal libertarianism, and with it Humean libertarianism. For the experiment, a number of 30 test persons was given the task to perform a simple movement of their wrist within a period of 30 seconds. Within these 30 seconds, the test persons could choose freely when exactly to move their wrist. The exact instant at which the muscle contraction began was measured using electromyography (EMG). Additionally, they were given the task to report when they had formed the conscious decision to move their wrist. In order to measure the exact point in time when the decision took place, Libet placed the test persons in front of an oscilloscopic clock. This clock consists of a dot of light which quickly revolves around a clock face. The dot completes a full cycle once every 2.4 seconds, i.e. 25 times faster than a normal seconds hand. The test persons were given the instruction to remember the position of the dot of light at the instant when the wish to perform the wrist-movement first occurred. Libet tested this method of measurement by giving test persons a slight electric shock and asking them to report the exact instant when they felt that shock by this method, which turned out to be sufficiently accurate. Approxim550 See Libet 1983. 551 See Libet 2002, p. 563.

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ately 550 msec. before the onset of a person’s deliberate motor action, an electrical impulse, the so-called readiness potential (RP), can be measured on the scalp of that person. In his famous experiment, Libet recorded the exact point in time of the occurrence of the RP. The interesting result and the reason for the experiment’s notoriety is that the test persons reported the forming of their conscious will to move their hand consistently at a point in time approximately 200 msec. before the onset of the motor act. If you subtract 50 msec. error you get a corrected time of decision of 150 msec. before the the actual physical action began. This means that the RP occurred approximately 300 msec. before the conscious wish to move the hand.552 Libet concluded that the brain already initiated the action before the agent even formed the wish to perform it. This is the reason of the experiment’s notoriety: in almost all positive accounts of free will, whether they are of compatibilist or incompatibilist ilk, the conscious will, however that might be spelt out in the individual theory of free will, is taken to be the cause of free actions. But how can the conscious will be causally relevant, if it occurs after the action has been initiated by the brain?553 Libet, who tried to defend the causal efficacy of the conscious will, postulated that the conscious will, even if it does not actually start the action, could abort it, so the agent has the ability to veto the action.554 This proposal is problematic for two reasons: firstly, even given that such an ability to veto an already initiated action actually exists and can be proven, Libet’s own account presupposes dualism: he takes the conscious will which he supposes to be able to veto a physical process within the agent’s brain as non-physical. While proposing dualism is not a criminal offence, it sheds some light on Libet’s original problem. To Libet, it was not merely the fact that the action seems to have been initiated before the test persons formed their will, it is the fact that it is something physical which predates the mental act.555 Not all libertarian theories and probably even less compatibilist theories presuppose dualism, so this non-physical veto as a universal 552 553 554 555

See Libet 2002, pp. 553-555. See Libet 2002, p. 555. See Libet 2002, pp. 556-557. See Libet 2002, p. 561.

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answer to the problem is out of the question. Secondly, we have seen in this chapter of the paper that an action must be caused by the appropriate reason-states in order to be controlled and intentional, and it would require further argument why one should accept that an action can be controlled and rational when it is merely not vetoed by the the agent. Fortunately, we do not have to reach for Libet’s own solution in order to counter the problem. Libet’s challenge has been met with a number of critiques, of which I will list and agree to three: Firstly, Henrik Walter e.g. objected that the actual decision to move the wrist does not take place when the test persons report the urge to move it, but when the test conductor instructs the test persons, hence the decision takes place well before the RP occurs.556 Secondly, Mark Balaguer e.g. objected that Libet’s experiment involved a very basic motor action: many of the most important decisions a person has to face in his life are much more complex and do not involve a directly following motor action. We do not yet know whether the RP occurs when we make more elaborate decisions which doe not necessarily involve direct motor action.557 A grumpy office worker might for instance decide to become less of a nuisance and treat his colleagues better in the future. In actions as these, we do not know whether an RP would be formed. Thirdly, and most importantly, Geert Keil and Mark Balaguer e.g. hold that – unless you presuppose dualism – Libet’s experiment in itself does not prove anything relevant at all, until we do not know what the RP actually does. It might be argued that conscious decision-making involves a lot of brain activity, and to identify some brain activity that precedes the conscious decision, which has a neuronal correlate or which, in materialism, even is some neuronal activity, does not entail that the conscious will is epiphenomenal. To show that, the defenders of Libet’s experiment must demonstrate that the according neuronal processes which constitute beliefs and desires are causally irrelevant, and to identify a neuronal process which precedes these processes simply does not do the trick. To arrive at a negative conclusion regarding free will, it has to be shown what exactly the causal function of the RP is, whether it renders the conscious decision causally ineffective and whether it plays any role in appointing the 556 See Walter 1999, p. 307. 557 See Balaguer 2010, p. 161.

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alternative which is chosen by the agent.558 Of these three criticisms, the last one is the most important. That some unconscious neuronal activity always precedes the will to act does not entail that the will to act is causally irrelevant. But we should not feel too secure here. It is very well possible that some day neuroscientists could decipher the exact neuronal processes that are the basis of beliefs and desires, and find out that these processes are causally irrelevant for actions. But until then, there is no reason to worry that beliefs and desires are epiphenomenal and hence that our actions cannot be controlled in the sense defined in this essay. This result does, however, ultimately make the truth or falsity of Humean libertarianism a partly scientific problem, i.e. a problem that can be settled by means of empirical scrutiny. For this and other reasons, Mark Balaguer reaches the same conclusion regarding his own libertarian proposal.559 I will leave the discussion of Libet’s experiment at that and return to control in Humean libertarianism.

4.2.3 CONTROL IN HUMEAN LIBERTARIANISM Humean libertarianism is starting to take shape. We have seen in the previous chapters that PAP is compatible with Humean determinism, but incompatible with determinism with a vengeance. We have also seen how a Humean might answer popular arguments such as the consequence argument and the Frankfurt-style cases. In this chapter, I would like to give an outlook how a Humean might construe control. As noted above, control is often discussed in terms of moral responsibility, although the two concepts are obviously not synonymous. The most important argument against a libertarian reading of control is the argument from luck. But control spawns another problem. We discussed the most prominent notions of control for event-causalism, proximal control and ultimate control, and have seen that both are problematic: ultimate control may not be tenable, and proximal control encounters the above-mentioned manipulation cases.

558 See e.G. Keil 2007, p. 171 and Balaguer 2010, p. 162. 559 See Balaguer 2010, p. 69.

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The solution I want to propose for Humean libertarianism is to do some cherry-picking and take the best from Mele’s, Kane’s, and Balaguer’s positions and then sprinkle some original Humean libertarianism on top. Humean libertarianism is in the unfavourable position to be exposed to the argument from luck no matter if determinism is true or not. If the Humean libertarian wants to claim that even if Humean determinism is true, there are alternatives open to the agent at the moments of decision, because the laws and the past do not compel a particular future, then she has to go all the way and accept that even in Humean determinism the future is partly a matter of luck. None of the above-mentioned notions of control or solutions to the problem of luck are applicable to Humean libertarianism in full. Unlike all standard libertarian accounts, Humean libertarianism does not require the truth of indeterminism, so we need a notion of control that is compatible with Humean determinism and indeterminism. But it is of no avail to simply propose some kind of control if it is not plausible. Luckily, I think it is. Let me elaborate. In this section, I wish to argue briefly for the following claims: (1) Although ultimate control as sketched by Strawson may be untenable, the actual event-causal libertarians propose a notion of control that is much less strong. A similar notion of control can be upheld by Humean libertarians. Kane and Balaguer are right that the most important aspect of control is that it is the agent’s beliefs and desires that cause her actions. But that also suggests that contrary to Balaguer, manipulation scenarios such as the alien implant case do demonstrate an important feature of control, i.e. that the agent’s beliefs and desires must be acquired nondeviantly. (2) This notion of control however entails that it is inevitable to join Kane and Mele in biting the bullet and simply accept that there always remains an element of luck if PAP is satisfied. The solution to this is to join Mele and to “try to stare down the problem of present luck”.560 (3) Mark Balaguer is right in maintaining that luck, or randomness, might be there to stay, but that it does not necessarily diminish control. Kane, however, produced some examples in which it does. (4) Contrary to Kane (and Balaguer in the case

560 See Mele 2006, p. 113.

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of torn decisions), and in accord with Mele’ daring soft libertarianism, the plurality condition does not hold, i.e. the alternative to a free action might be an unfree, irrational, or even uncontrolled action. Let us try to make these claims plausible with the use of two scenarios. Stephen just graduated from school and now he ponders whether to join the army or go to university straightaway. The army would provide Stephen with an opportunity to spend some time before he goes to university, and he hopes that his time in the military could help him to make up his mind what career would be the best for him. Stephen considers studying avionics, which he could study at a well-reputed army university as well as at a civil university. Also, he likes the idea of earning some money while studying. On the other hand, Stephen dislikes weapons and is morally not comfortable with the prospect of possibly being sent abroad to some conflict, where he perhaps would have to fight for a cause he does neither understand nor accept. So Stephen broods over the decision for a while, and then decides not to join the army but to go and study avionics straightaway at a civil university. To the Humean, this decision is not forced by the laws and the past – it may even be undetermined. Stephen has got some good reasons to act either way, so when he finally reaches a decision, it is a decision caused by his own reason-states. His character, his motives, beliefs, and desires cause him to study straightaway, and after he reaches his decision, he endorses this decision and the subsequent action as his own. If he had decided to join the military instead, it also would have been his reason-states that caused the action. Either way, he overcomes the possibility of acting on a different set of reason-states, he overcomes the possibility that the prevailing reasons to act could fail. Similarly, his action is rational as well as it is under his control, since it is done for a set of reasons. It is no fluke, no action that he could not explain himself. When asked why he did not join the military, Stephen can list a number of beliefs and desires that made him chose not to. Consider a second example. Everything is exactly like in the first example, except that Stephen’s beliefs and desires for not joining the military but studying straightaway were, unbeknownst to Stephen, implanted into him by a peace-loving alien. Stephen does not realise that he was manipulated, and the alien even manipulated Stephen’s memory so that he

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feels that these pacifist beliefs and desires are originally his own. The alien, being a thorough pacifist, also eradicated Stephen’s beliefs and desires to the join the military, while he left Stephen’s belief that there is the objective possibility to join the military intact. Thus, Stephen knows that he could join the army, but he has no reasons to do so. Hence, he still has to make a decision, albeit an easy one. Subsequently, Stephen acts on the implanted reason-states and decides not to join the military. With these scenarios in mind, let us try to argue for claims (1)-(4) one by one: (1) Stephen controls his actions in case 1 in the sense that it is Stephen who causes them. Stephen has reasons to join the military, as well as to study straightaway. In each of these cases, it is a set of reason-states that causes Stephen to act. At this stage, at least 2 objections are possible. Firstly, it might be asked where these reason-states came from. Can Stephen be free when the beliefs and desires he has were caused by external factors or factors beyond his control? Secondly, one might ask whether a condition as weak as requiring that an action was caused by a reason-state of the agent is actually sufficient for the action to be under the control of the agent. To answer the first objection, let us remember the different types of control that are left after rejecting agent causation and noncausalism: proximal control and ultimate control: Proximal Control = An agent has proximal control over her actions iff her actions are caused by her beliefs and desires. Ultimate Control = An agent has ultimate control over her actions iff they are caused by her beliefs and desires and these beliefs and desires were chosen by the agent. As noted above, ultimate control is problematic. To recall, Strawson rejected it on the basis of a dilemma that he concluded ultimate control by reasons would entail: To ensure that reasons are caused by the agent and not ultimately by something external to the agent, it would be natural to demand that these reasons have to be caused by other reasons. But then a regress looms, as these reasons would also ultimately have to be caused by other reasons within the agent in order to fulfil the requirements of ultimate

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control, and so on. In order to stop this regress, a defender of ultimate control would have to state that some reasons which ground other reasons are chosen without the guidance of higher order reasons, or that the reasons may be innate, or simply be caused externally.561 Does that leave us with proximal control? Mark Balaguer for example did not require any further conditions over and above the requirement that free actions must be caused by reason-states of the agent, which yields a notion of proximal control.562 Proximal control is an originally compatibilist notion of control. What sets a libertarian notion of control apart from a compatibilist notion is a requirement that the reasons an agent acts for are not ultimately determined by factors outside the agent. Mele satisfies this criterion in modest libertarianism by holding that some reason-states just indeterministically pop up inside the agent’s mind.563 In daring soft libertarianism, no further requirement for control is proposed, because Mele’s daring soft libertarian accepts the possibility that determinism (with a vengeance) may turn out to be true.564 Kane satisfies this further demand on control by stating that SFA’s, which shape the agent’s character, must be undetermined.565 Balaguer again does not propose a further constraint on control over and above that is must be the agent’s own reason-states which cause an action, but he as well holds that an agent can only be free if some of his actions are undetermined. At least some of these undetermined actions again contribute to shaping the agent’s character.566 So what about the Humean libertarian? Obviously, in Humean libertarianism, we cannot use a notion of control that presupposes the falsity of Humean determinism. Instead, as Humean determinism does not prohibit the power to do otherwise as defined in chapter 4.1.1, we need a notion of control that is stronger than the typically compatibilist notion of proximal control to highlight the fact that because agents have the power to do otherwise, they contribute to shaping their own characters. While a Humean 561 562 563 564 565 566

See Strawson 1986, pp. 28-29 and 48-50, and 1994, pp. 12-14. See Balaguer 2010, pp. 97-99. See Mele 2006, pp. 10-13. See Mele 2006, p. 95 and 80, n.23, for Mele’s necessitarian confession. See e.g. Kane 1996, p. 60. See Balaguer 2010, p. 74.

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libertarian notion of control may have to be stronger that proximal control, it also has to be weaker than the untenable Strawsonian notion of ultimate control, which, as we have seen, none of the most prominent event-causalists propose anyway.567 Still, some of our most basic beliefs and desires may be caused by interaction with our surroundings. Such interaction may be education, experience, or even manipulation (we will turn to manipulation cases a few lines below). An agent need not, indeed she cannot, be a causa sui or the ultimate source of all his beliefs and desires. All that is required for her to be in control is that she can develop her beliefs and desires further, that he can shed them, strengthen them and weigh them in decisions which are not necessitated. So this is my tentative proposal: HL-control: An agent is in control of her action iff that action is caused by one or more of the agent’s reason-states which are the unnecessitated consequences of her genetical makeup, the causal interaction with her surroundings, and her own deliberative mechanisms. These reasons have to be able to undergo a conscious life-long reason selection process. Before we wrap up, we have to make an excursion here and return to the causes of our beliefs and desires. There is a debate amongst defenders and attackers of compatibilism about the causes of our reasons for which we act. Some of the opponents of compatibilism hold that a compatibilist notion of control, i.e. something like proximal control as defined here, is actually compatible with manipulation cases in which we intuitively would not consider the agent in control of her actions. Mele holds that the manipulation arguments all have a similar structure: We are shown a manipulated agent, Mele calls him Manny, which we intuitively hold not responsible for his actions. That Manny is not responsible is the first premise (the Mannypremise). The second premise is that there is no significant difference between Manny and a normal unmanipulated agent living in a deterministic world (the no-difference premise). Hence, determined agents are not responsible for their actions.568 567 Geert Keil holds that it is a myth that libertarians propose that the free will must be entirely unaffected by external factors. Keil claims that no serious libertarian ever proposed such a view (see Keil 2007, pp. 92-94). 568 See Mele 2008, p. 265.

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Before we discuss the most prominent manipulation argument, an important caveat is in order. Originally, arguments such as this were designed to show that compatibilists have no satisfactory notion of responsibility. So why do we have to discuss them here? Because in these arguments, responsibility is defined in the same vein as we defined control: there is a traditionally compatibilist notion of proximal responsibility in which an agent is responsible iff her actions are caused by her beliefs and desires, and an ultimate, traditionally incompatibilist notion of responsibility in which an agent is responsible for her actions iff her actions are caused by her beliefs and desires and if her beliefs and desires are not causally determined by anything outside the agent.569 Again, I do not want to discuss moral responsibility, because I agree with Mark Balaguer that moral responsibility and freedom should be discussed separately.570 But if, as we have seen, responsibility is defined so similarly, one might ask whether these authors are not also discussing control and not only responsibility. In fact, it seems as though the arguments for or against responsibility could be phrased so that the agents have or lack responsibility in these arguments because they have or lack control over their actions. Derk Pereboom, who devised the important four-case argument we will discuss now holds that: “[...] if an action results from a deterministic causal process that traces back to factors beyond the agent’s control, then he is not morally responsible for it”.571 What these arguments have to show then is that the respective agents in them have no control over their actions. In the discussion of the arguments, I will stick to the term responsibility rather than control, because I do not wish to distort the respective authors’ terminology. When I discuss the implications of these arguments for HL-control I will switch back. Moreover, in these discussions it is always presupposed that the proximal notion of responsibility is compatibilist and the ultimate notion is incompatibilist. The authors that partake in the debate about these arguments do not usually consider Humeanism, and Alfred Mele, who did consider Humeanism in his 2002 paper with Helen Beebee, explicitly presupposes 569 See Strawson 1994, pp. 16-17 570 See Balaguer 2010, pp. 39-44 for his argument to this effect. 571 Pereboom 2001, p. 116.

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necessitarian determinism in his discussion of the manipulation arguments.572 So these arguments are no counter-arguments to Humean libertarianism, because they presuppose that an agent does not have a power to do otherwise if determinism is true as we discussed in chapter 4.1. Yet still, these arguments are instructive because they sharpen our view on the question of what conditions must be fulfilled so that we intuitively regard an agent in control of her actions. The most prominent manipulation argument is Pereboom’s famous four-case argument. Pereboom asks us to imagine Professor Plum, who is often rationally egoistic, which in a certain situation leads him to kill Ms. White. Pereboom designs four cases in which Plum is decreasingly manipulated to commit his murder. In the first case, Plum is created by neuroscientists (Team Plum, as McKenna calls them),573 who subsequently go on to permanently control each and every move of Plum. They implant beliefs and desires and manipulate how Plum processes these beliefs and desires. By this, team Plum manipulates Plum in such a way so that they make him kill Ms White. In the second case, they do not control him directly up to the kill, but they programmed his beliefs and desires and the way they are processed by him beforehand, so that when he is in a situation such as exactly before Ms. White’s killing, Plum kills. In the third case, Plum is a normal person, but when he was a child, he was so brainwashed and trained that he had the kind of beliefs and desires such that whenever Plum is in a situation such as before Ms. White’s killing, Plum kills. In the fourth case Plum is an ordinary human being living in a deterministic universe who was ordinarily brought up, which deterministically caused him to hold the beliefs and desires that make him kill Ms. White. Pereboom asks us in what way, given that determinism is true, is the fourth Plum more responsible for his action than in the first three cases? In cases 1-3, we would say that Plum is not in control of his killing, but what about case four? What makes case four so special that the compatibilist can hold him responsible? According to Pereboom, in all four cases Plum’s beliefs and desires were

572 See Mele 2006, p. 80, n.23 573 See McKenna 2008, p. 149.

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ultimately caused by factors outside the agent. Pereboom concludes that an agent cannot be responsible if his choices and the options to choose from are determined574 There are three ways to respond to this argument.575 Firstly, one could reject the Manny-premise and hold that Plum actually was responsible in cases 1-3. This is the way Michael McKenna responds to this argument.576 Secondly, one could reject the no-difference premise and hold that Plum is not responsible in cases 1-3 because his reason-states do not have the right history. This is Alfred Mele’s, John Martin Fischer’s, Mark Ravizza’s, and Ishtiyaque Haji’s response to these arguments.577 Thirdly, one could reject the no-difference premise and hold that Plum 1-3 was not responsible for killing Ms. White because the relevant reason-states are not properly integrated in his mesh or hierarchical system of beliefs and desires. This is e.g. Harry Frankfurt’s and Michael Bratman’s view, which we will not discuss here.578 I will instead focus on the first two ways of responding to this argument. As the manipulation arguments are no straight counterexamples to Humean libertarianism, we do not have to look at each and every argument and counter-argument, for that would be a very laborious and ultimately superfluous task for our purpose at hand indeed, but I will do some cherrypicking again and pick out the most helpful responses which help us shape a tenable notion of control in Humean libertarianism. Alfred Mele pointed out that determinism cannot be the relevant factor in Pereboom’s argument. Mele asks us to imagine an indeterministic process attached to Plum’s decision-making such that when he is about to reach a decision, there is the slight chance of a breakdown of his mental capacities. Even with that sort of indeterminism built in, we would still not regard Plum as responsible in cases 1-3. Accordingly, that Plum is determined to kill by a set of reason-states does not seem to be the relevant factor 574 See Pereboom 2001, pp. 111-115. 575 For a very comprehensive overview, which helped me tremendously to shape this section, see McKenna 2009. 576 See McKenna 2004 and 2008. 577 See e.g. Mele 1995, 2006 and 2008, Fischer and Ravizza 1998, Fischer 2004 and 2007, and Haji 1998.) 578 See e.g. Frankfurt 2002 and Bratman 2003, 2004 and 2007.

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for not holding him accountable for the kill in cases 1-3.579 Mele holds that because determinism is not the relevant factor here, the argument does not show what it was designed to show: that determinism renders agents unable to be responsible for their actions. Rather, Mele proposes that ascriptions of freedom and responsibility are history-sensitive. What makes us think that Plum 1-3 is not responsible for his own actions is the fact that the reason-states he decides for are manipulated, that they have a deviant history.580 Plum’s history renders him not responsible in the manipulation-cases because his normal reasons-processing mechanisms are bypassed: the manipulation renders Plum incapable of shedding the reasons that lead him to kill Ms. White, or to acquire reasons that would prevent him from the deed.581 Mele also holds that manipulation does not necessarily preclude responsibility. A person who in the course of his life sheds the manipulated beliefs and desires, or acts upon other beliefs and desires she nondeviantly acquired, may very well be responsible for her actions.582 Michael McKenna offers a different line of response. While Mele attacks the no-difference-premise, McKenna attacks the Manny-premise. He holds that the defender of proximal control should better disagree with Pereboom’s claim that Plum 1-3 is not responsible for his killing. He holds that even Plum in case 1 can be responsible for his act, if the scenario is amended in a certain way. The key is how to construe the workings of team Plum. If Plum is an ordinarily functioning human being who is able to causally interact with his surroundings and deliberate about his beliefs and desires, and team Plum merely functions as what McKenna calls a “causal prosthetic” which simply provides the causal input Plum would have got anyway in an unusual manner, Plum can be a responsible agent even if team Plum sometimes remotely controls Plum. The other manipulation 579 See Mele 2006, pp. 142-144 and 2008. Yet another argument concerning proximal control has been proposed by Alfred Mele, the so-called “zygote argument”. We will very briefly turn to this argument below (See Mele 2006, pp. 188-195 and 2008, pp. 280-284.) 580 See Mele 2006, p. 166. 581 See e.g. Mele 2008, p. 271. 582 See Mele 2006, p. 167. For objections, see Dennett 2003, Arpaly 2003, and Kapitan 2000. For Mele’s responses, see Mele 2006, pp. 173-187.

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cases can be construed similarly: if the manipulators do not put Plum “out of the causal loop”, and his normal reasoning mechanism remains intact, Plum may still be a responsible human.583 Mele and Fischer partly agree. Both hold that in certain manipulation cases, though not necessarily in case Plum 1, the manipulation is such that it holds Plum’s normal mechanisms for evaluating and shedding his beliefs and desires intact, so he can still form his character in causal contact with the world, even though some of his beliefs and desires were ultimately determined by team Plum. 584 To make this claim plausible, Mele provides an influential manipulation argument that is designed to show that even manipulated agents can be responsible. Consider a goddess, Diana, who wants that a certain agent, Ernie, does A at a particular time in the future. For this, she designs a zygote and implants it into Mary’s womb. Diana equipped the zygote that is to become Ernie with all the properties that ensure that in a deterministic universe of whose exact state and laws she has information, Ernie does what Diana wants at that certain time in the Future. Now consider Bernie, who is exactly like Ernie except that Bernie was conceived in a regular way without an interfering goddess. Mele holds that Bernie is no more responsible for his actions as Ernie, since both of them where left alone by meddlesome goddesses after their birth and both where able to shape their beliefs and desires in a normal way with their deliberative systems through causal interaction with their surroundings.585 Let us return to the issue of control. Although not all of the arguments of the compatibilist manipulation debate about moral responsibility can be transformed in order to fit our notion of control, because these arguments often rely on moral intuitions and are deeply rooted in the debate about compatibilism, the responses by Mele and McKenna in particular are very instructive in order to understand the notion of control a Humean libertarian can have. Remember the second scenario in which Stephen decides not to join the military. His decision is caused by a set of reason-states implanted into his mind by a peace-loving alien. Would we intuitively consider Stephen a free agent who is in control over his decision not to join the 583 See McKenna 2008, pp. 149-152. 584 See e.g. Fischer 2006, p. 232 and Mele 2006, pp. 142-144. 585 See Mele 2008, pp. 279-280 and 2006, pp. 188-195 .

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military? Probably not. But let us not jump to conclusions here. Consider the following two scenarios: In the first case, the alien implants Stephen’s pacifist reason-states immediately before his decision and blocks any process of evaluating, weighing, or shedding these reason-states. We would hardly take Stephen to be in control of his decision not to join the military. But what about the second case: The hippie alien implanted Stephen’s pacifist beliefs and desires 5 years before his actual decision and left his mind otherwise intact. Over the years, Stephen was able to evaluate, shed, strengthen, and weigh his reasons in his unnecessitated decisions, but his pacifist reason-states stayed with him; in fact, Stephen grew quite fond of them. Over the years, he had many opportunities to shed them and strengthen his bellicist side, but he did not. If, after some years, he decides not to join the military, why should we not consider him in to be control of this action? So to conclude, if an agent has the opportunity to shape his character over a long time by making decisions which are open in the sense of PAP, it does not matter if these reasons were innate, caused by external factors, or implanted. If a manipulator wants to rob an agent of her control of these actions, she has to make sure that the agent is not able to shed, weigh, strengthen and evaluate them. Only then the agent is not in control of her actions. That also demonstrates why Humean libertarianism proposes a kind of freedom worth wanting: by acknowledging PAP and PPDO, Humean libertarianism does procure the agent with enough leeway to be able to sidestep manipulation cases and to be free in the face of Humean determinism. In (necessitarian) compatibilism, even the process of shedding, weighing, evaluating and strengthening of reason-states is necessitated. Not so in Humean libertarianism. The leeway opened up by PAP saves us from the inevitability of a necessitarian determinism with a vengeance in which each and every step of us would be necessitated by the laws and the initial conditions. Indeed, Alfred Mele realised the potential that Humeanism has in this debate. He recognises that Humeanism about laws may not be very popular, but that a manipulation scenario such as the zygote case would not be a counterexample to a Humean position, because Ernie’s decisions contribute to what the laws may be. So Diana cannot know the laws when she creates Ernie. She may make a guess, she may even be right – after all,

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Humeans do not suppose that nature has to be irregular – but she cannot know. Since Ernie’s actions contribute to determining what the laws will be, he is not compelled to act as Diana planned. Hence her design cannot render Ernie powerless regarding his choices: “On a Humean view of laws, in Gideon Rosen’s words, ‘it may turn out that the laws are as they are in part because’ Ernie acted as he did.”586 To spell out this view is the very aim of this book. With these considerations in mind, HL-control as defined above: HL-control: An agent is in control of her action iff that action is caused by one or more of the agent’s reason-states which are the unnecessitated consequences of her genetical makeup, the causal interaction with her surroundings, and her own deliberative mechanisms. These reasons have to be able to undergo a conscious life-long reason selection process. together with PAP seems to cope quite well with these manipulation cases. I will leave HL-control at that. Because Humean libertarianism acknowledges PAP it can sustain a significantly stronger notion of control than compatibilist notions. Still, HL-control remains weaker than ultimate control as attacked by Galen Strawson. But, as we have seen, this much control might not be had anyway, so HL-control is as strong as it gets, provided that some form of Humean analysis of natural laws and determinism is true.

(2) After the discussion of Mele’s, Kane’s and Balaguer’s answers to the problem of luck, it is safe to say that there is always a moment of luck if PAP is fulfilled. We have seen in chapter 4.1 that even if Humean determinism was true, agents would still have the power to do otherwise. But if we take the proposal serious that there are real possible alternatives in free actions even if Humean determinism is true, we have to concede that our actions are always partly a matter of luck. I agree with the abovementioned libertarians that luck is there to stay. The important question is if and how much this moment of luck diminishes control.

586 Mele 2008, p. 284, original quote and italics. Mele quotes Rosen 2002, p. 705.

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(3) That an action is partly a matter of luck does not necessarily diminish HL-control. Stephen ponders whether to join the army or study straightaway and is not compelled to act either way. When he decides to study straightaway, his decision is caused by his very own reasons, it is Stephen who decides and endorses what to do. I agree with Balaguer, 587 who holds that given that a decision is really open, we should expect Stephen to decide differently in different reruns of the decision after God pressed the replay button. Still, it was Stephen who authored and controlled the action in the sense that it was his reason-states which caused the action, that it was him who decided. In fact, we would be suspicious if Stephen did not decide differently in different reruns of the decision. That both outcomes of Stephen’s decision are compatible with his past and his reason-states is an indicator that the decision was really open – which is exactly what we expect if an agent has the power to do otherwise. But there is one sense in which indeterminism might diminish control, and that is wonderfully illustrated by Kane’s case of the three assassins. Remember the three assassins who wanted to kill the PM. One assassin was a young, stud assassin who had a 100% chance of hitting his target. The other two assassins had an 80% and a 50% chance of hitting the PM due to nervous twitches in their arms. Kane holds that the young, stud assassin has more control over his action as the other two.588 A similar example is given by Robert Audi: Consider Tom, who is a very poor golfer. Tom tries to hole a putt, swings wildly about, hits the ball accidentally on his backswing, the ball flies around, hits a tree and a golf cart and lands in the hole. Would we say that Tom was in total control of his action?589 Obviously not. Similarly, the assassins have differing control over their actions. So how can we resolve this tension between saying that although our everyday decisions a partly a matter of luck, they are under our control and on the other hand claim that accidentality diminishes agential control? There is one crucial difference to be made: In the assassins and the golfer cases, the accidentality is located after the decision. The nervous assassins and the hapless golfer have diminished chances to fulfil their 587 See Balaguer 2010, p. 93. 588 See Kane 2007, pp. 39-40. 589 See Audi 1986, pp. 527-528.

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decisions, hence their actions are not entirely under their control. But the luck objection that Balaguer tried to solve concerns the question which reason-state causes the action. That luck at a later stage diminishes control does not entail that it diminishes control at an earlier stage. According to this analysis, Tom the hapless golfer has full control over trying to hole the putt, because it were his reason-states which caused the try to hole the putt, but because of his ineptitude he had a greatly diminished control over the success of his attempt. There is no tension between these cases.

(4) Lastly, I join Alfred Mele in his view that the plurality condition does not hold. In his defence of daring soft libertarianism, Mele holds that an action can be free, even if its alternative is no free, controlled action, i.e. if there are nonrobust alternatives available. The Frankfurt-style cases provide counterexamples only to those libertarian theories which hold that free actions not only have to satisfy PAP, but also the additional condition that the alternatives must be robust in the sense that the agent performs different free, controlled actions in all of them.590 Mele also holds that this additional condition requires independent defence.591 Consider the Frankfurt-style cases. We have already seen above that a Humean might say that an agent who is influenced by a Frankfurtian intervener still has the power to do otherwise in a relevant sense: she can bring about an alternative in which the action was caused by the intervener, not her. In this case, she is not free. But she is free in the case where she acted on her own. So it seems perfectly possible that the alternative of an action might be an unfree action, or maybe even no action at all. The Frankfurt-style cases demonstrate exactly that: we would intuitively hold that Jones is free if he choses to vote for Gore on his own. But in such a case, Jones has a nonrobust alternative open before him. We would not consider Jones free if he has no alternative possibilities open before him at all, which would be the case if determinism with a vengeance was true. As seen above, Kane introduced the plurality condition mainly to defend his position against the argument from luck and in order to sustain ultimate responsibility. Since I hope to 590 See Mele 2003, pp. 252-253, and 2006, p. 115. 591 See Mele 2006, p. 124.

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have demonstrated that the argument from luck can be answered and HLcontrol can be upheld even without the application of a plurality condition, we have no need to propose one. So before we move on, let us try to give a definition of a free action in Humean libertarianism: An agent’s decision is HL-free iff at the moment of decision t there exist at least two real alternatives h and h’, neither of which is necessary with a vengeance and the agent has the power to cause either of them. The proximate causes of this decision have to be one or more of the agent’s reason-states which are the unnecessitated consequences of her genetical makeup, the causal interaction with her surroundings, and her own deliberative mechanisms. These reasons have to be able to undergo a conscious life-long reason selection process. As seen above, this does not require the truth of indeterminism, although it would not be inconsistent with it, and neither does it require some extra factor such as an agent-substance. It neither makes divine prime movers unmoved out of us humans, nor does it make us the playthings of nature. Such a freedom seems to be worth wanting indeed.

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5 HUMEAN LIBERTARIANISM: FORTES, FOIBLES, AND FUTURE FOLLIES Let us conclude. As mentioned repeatedly above, this essay should merely outline HL and show that it can answer most of the arguments given against traditional libertarianism. Let us try to evaluate its success concerning this task by giving a brief overview over HL’s advantages and disadvantages. To conclude, I will also give an outlook on what further work needs to be done.

FORTES Most of the authors in the free will debate do not give an integrated account of determinism and laws of nature which can be combined with their respective views on free will. In fact, the debates about determinism and laws of nature are mostly ignored in the free will debate, although the importance of natural laws and determinism for the free will debate seems to become increasingly noticed. While authors such as Helen Beebee, Alfred Mele, David Lewis, Kadri Vihvelin, Norman Swartz, John Earman, Geert Keil and Thomas Buchheim recognise the potential import a Humean view on laws of nature might have for the free will debate, none of these authors pays equal attention to laws of nature, determinism and freedom. To fill this gap and make a tentative proposal of a Humean libertarian theory was the aim of this essay. We have seen in chapter 4 that the consequence argument in conjunction with the hypothesis that determinism is true, the Frankfurt-style arguments, the arguments regarding the empirically questionable claims the traditional libertarians make, the argument from luck, and the argument from Libet’s work can be answered either independently or against the backdrop of a Humean theory of laws of nature. Another advantage of a Humean theory of any kind is its ontological austerity. For determinism and laws of nature, it is the commitment to Humean supervenience that excludes metaphysically demanding notions

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such as modal forces in nature. Humeanism regarding laws of nature does not require a specific theory of universals as it is necessary in Armstrong’s account, nor does it require essentialism as in Bird’s theory. Of course, ontological austerity in itself is no argument for or against a position. But we have seen in chapter 2 that the MRL-view and the BBS-view are defendable theories. The same picture emerged in the other half of this essay. We have seen that a Humean account of libertarianism does not need agent substances or uncaused actions, it does not even require the truth of indeterminism. We have also seen in chapter 3.2 that contemporary theories of agent causation propose the truth of a necessitarian theory of causation and laws of nature such as Bird’s view or the ADT-account. On close inspection we have seen that agent causation is not compatible with dispositionalism and the ADT-view, indeed these theories of free will seem to be incompatible with any of the existing theories of causation and laws of nature. Humean libertarianism, as an event-causal account, can avoid these problems. Moreover, Humean libertarianism does not require a notion of ultimate control as it is argued against by Galen Strawson. Humean libertarianism does not hold that a human agent is a causa sui in the sense that she is the ultimate source of every feature of her character. We have seen that traditional event-causalism, at least in the contemporary form of Mele’s, Kane’s, and Balaguer’s view, does not propose such a notion of ultimate control either. What sets Humean libertarianism apart from its traditional event-causal libertarian cousins is its greater compatibility with actual science. Humean libertarianism does not need to propose the truth of indeterminism. Whether determinism is true is a question which is, as we have seen in chapter 1, not yet settled. That quantum theory is an indeterministic theory is by no means uncontested. To be fair, the proponents of deterministic interpretations of quantum theory are probably in a minority, but the dispute still remains open. What speaks in favour of Humean libertarianism is that it is compatible with Humean determinism as well as with indeterminism. Accordingly, HL does not require any indeterministic processes in the agent’s brain. As we have seen in chapter 4.1.3, the specific indeterministic neuronal processes as proposed by the various participants of the debate are empirically questionable. Jordan’s original amplifier theory is com-

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monly deemed to be refuted, Penrose’s and Hameroff’s account has met very serious opposition, and Kane’s account of an indeterministic parallel processing of competing efforts of will has no empirical grounding whatsoever. To be fair, it is not yet empirically refuted, but it is highly speculative nonetheless. Balaguer’s view is empirically less demanding, but only because he does not make any positive claims about the nature of neuronal processes. However, Balaguer’s libertarianism also requires that at least some of our decisions and their underlying neuronal processes are indeterministic. Humean libertarianism shares with all event-causal libertarian theories the commitment that beliefs and desires are causally effective. If some day the neurosciences should identify the proper neuronal states that constitute beliefs and desires and if these neuronal states should turn out to be epiphenomenal, then none of these theories is tenable, and HL is no exception here. But this empirical refutability should not be taken as a disadvantage, as long as the empirical consequences of theories of free will are not as bold as in Kane’s or P&H’s accounts.

FOIBLES As any philosophical account, HL is not without its weaknesses. The main objection most likely will be that the proposed account of PAP and PPDO, because it allows indeterminism as well as Humean determinism, is too wide to meet the demand of libertarianism. As argued in chapter 4.1, the Humean notion of the openness of the future is a direct consequence of the Humean account. All Humean accounts hold that the laws supervene on the occurrent facts, thus what the occurrent facts are for the whole history of the universe is not yet settled. Hence, the future is open in the sense that it is not yet decided what the laws will be. It is not our actions that are the consequences of the laws (at least not until the end of time), but it’s the laws that are the consequences of our actions. But to repeat, and we should not be blinded by the Humean’s rhetoric here, the Humean view of laws of nature does not commit the Humean to the view that humans can run at superluminal velocity if they want to. As it seems now, we have every reason to expect that nature behaves regularly in the sense that science

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seems to have discovered regularities that have held so far and we expect them to also hold in the future. Of course, we do not know whether the regularities discovered so far will hold in the future, but, as discussed above, this is nothing but the problem of induction. Related to the unease about the Humean notion of PAP and PPDO, there is the concern that HL is just a compatibilism in disguise. To rephrase a self-critical question asked by Mark Lange: am I cheating?592 After all, I have repeatedly claimed that HL is compatible with Humean determinism. But let us not overlook that HL is not compatible with any necessitarian view of laws of nature and determinism. Humean libertarianism is an incompatibilism regarding modal forces in nature. If determinism with a vengeance is true, we are forced to act as we act and hence we are not free. What I tried to achieve in this text is not just fancy wordplay. It was the very aim of this book to clear up a major misapprehension that is very common in the debate about free will: in most publications, freedom is tested against an unspecified determinism. Claims are being made on a regular basis whether freedom is compatible with determinism without giving a proper definition of determinism and without discussing whether determinism involves modal forces. To commit a theory of free will to the truth of Humeanism is risky. Humeanism concerning laws of nature is not particularly popular at the moment. Necessitarians might indeed be inclined to take this essay as a good reason to rid themselves of two unpopular theories: Humeanism regarding laws and libertarianism. To defend a MRL- or BBS-view of laws of nature is no easy task given the ferocity of the attacks from such formidable authors such as David Armstrong and Alexander Bird. But firstly, the arguments against Humean supervenience have turned out not to be conclusive. We have also seen that the necessitarian views have severe problems of their own which are by no means less severe that those of the MRL- and BBS-views. With the BBS-view, the Humeans have the decisive advantage to offer a view of natural laws that can cope with special science laws which require supervenient kinds. This advantage is particularly

592 See Lange 2009, p. 188.

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important for the free will debate if we consider that with a theory of special science laws, we could maybe offer an account of psychological or neuroscientific laws which hold for human action.

FUTURE FOLLIES The work is not yet done. To tie a notion of libertarianism to an MRLor BBS-view requires the continuous defence of these theories of laws of nature. So some of the future work for the Humean libertarian does not lie in the defence of her libertarian theory, but in the further defence of her theory of natural laws. In chapter 2 the question whether an MRL-view has to be amended with the BBS-view or not was left undecided. Both theories have their share of problems. As noted above, the MRL-view’s most pressing problem is the problem of language and the resulting problem of intersystem comparability. The defendant of an MRL-view has either to argue for natural properties or for a stipulation of kinds as discussed in chapter 2. Furthermore, it remains very exciting to see how the BBS-view will fare in the future. This proposal is still fairly young and it remains to be seen how its defenders answer the criticism levelled against it. The main criticisms against the BBS-view are the problem that it may turn out to fail Psillos’ realism test, that it may be subject to Lange’s dilemma, that the idealisations that are part and parcel in the special sciences might yield laws or even entire best systems without instances, and that it still fails to offer a criterion of intersystem comparability. To elucidate these questions is not only worthwhile in itself, but also necessary in order to sustain HL. Over and above the debates in natural philosophy and philosophy of science discussed here, there also remain open questions concerning HL’s notion of freedom. A large part of the debate about free will centres around one notion that I have mentioned only in passing: responsibility. Theories of freedom are often judged by their ability to give an account of human agents as moral subjects. I have not yet investigated the moral implications of HL and that work some day has to be done. However, if Strawson’s suspicion is correct that the arguments against the various libertarian theories’

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accounts of responsibility rest upon the claim that these theories cannot sustain agential control, I am confident that these arguments can be met by the defence of control given above.

I hope that this essay, even if it did not convince the reader of Humean libertarianism, has demonstrated the importance of the debate about natural laws for the debate about free will. It is an unfortunate historical artefact that more authors of the free will debate have discussed the ethical implications of free will than its grounding in natural philosophy and philosophy of science. Hopefully, this essay was able to fill this gap. Since many of the recent additions to the free will debate which do consider the implications that theories of laws of nature have for the free will debate are quite recent, I hope this essay can further fuel this debate in order to elucidate the implications of natural laws and free will. To conclude, Humean libertarianism offers a view that is not as ontologically and empirically questionable as traditional libertarian views and offers a stronger notion of freedom than compatibilism. It neither renders us agents as implausible godlike creatures who are over and above the physical events as the agent-causalists are trying to portray us, nor does it entail empirically questionable consequences about neuronal processes, nor does it make us the playthings of nature. As such, Humean libertarianism offers a notion of freedom worth wanting indeed.

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