On the genealogy of color : a case study in historicized conceptual analysis 9781138928145, 1138928143

Table of contents :
1. The Problem of Color Realism 2. The Aristotelian Strand 3. The Cartesian Strand 4. Descartes's Quandary 5. Moving Beyond the Problem of Color Realism

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On the Genealogy of Color

“Adams’s book offers a richly textured history of the interplay between theoretical components in our evolving concepts of color.” —Jonathan Cohen, University of California San Diego, USA “This book is impressive not just because it shows how our ‘ordinary’ concept of color involves incompatible commitments inherited from radically different philosophical theories of color, but because it also demonstrates how awareness of the history of philosophy can completely change how we think about contemporary debates.” —Nat Hansen, University of Reading, UK In On the Genealogy of Color, Zed Adams argues for a historicized approach to conceptual analysis, by exploring the relevance of the history of color science for contemporary philosophical debates about color realism. Adams contends that two prominent positions in these debates, Cartesian antirealism and Oxford realism, are both predicated on the assumption that the concept of color is ahistorical and unrevisable. Adams takes issue with this premise by offering a philosophical genealogy of the concept of color. This book makes a significant contribution to recent debates on philosophical methodology by demonstrating the efficacy of using the genealogical method to explore philosophical concepts, and will appeal to philosophers of perception, philosophers of mind, and metaphysicians. Zed Adams is Associate Professor of Philosophy at The New School for Social Research, USA.

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73 On the Genealogy of Color A Case Study in Historicized Conceptual Analysis Zed Adams

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On the Genealogy of Color A Case Study in Historicized Conceptual Analysis Zed Adams

First published 2016 by Routledge 711 Third Avenue, New York, NY 10017 and by Routledge 2 Park Square, Milton Park, Abingdon, Oxon OX14 4RN Routledge is an imprint of the Taylor & Francis Group, an informa business © 2016 Taylor & Francis The right of Zed Adams to be identified as author of this work has been asserted by him in accordance with sections 77 and 78 of the Copyright, Designs and Patents Act 1988. All rights reserved. No part of this book may be reprinted or reproduced or utilised in any form or by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying and recording, or in any information storage or retrieval system, without permission in writing from the publishers. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data Adams, Zed. On the genealogy of color : a case study in historicized conceptual analysis / Zed Adams. — 1 [edition]. pages cm. — (Routledge studies in contemporary philosophy ; 73) Includes bibliographical references and index. Color (Philosophy) I. Title. B105.C455A33 2015 111'.1—dc23 2015027148 ISBN: 978-1-138-92814-5 (hbk) ISBN: 978-1-315-68201-3 (ebk) Typeset in Sabon by Apex CoVantage, LLC

Dedicated to Rebecca Childers

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The aim is not to doubt or debunk, but to understand. —John Haugeland

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Contents

Figures Preface: Disentangling Our Concept of Color Acknowledgments 1

2

3

The Problem of Color Realism 1.1 Cartesian Anti-Realism 1.2 Oxford Realism 1.3 Survey of Considerations in Support of the Intrinsic View 1.4 Experimental Evidence 1.5 The Need for a Genealogy of Color

xiii xv xix 1 2 3 9 13 18

The Aristotelian Strand 2.1 Aristotle on Perception 2.2 Color as the Proper Object of Vision 2.3 The Doctrine of Species 2.4 The Aristotelian Distinction between True and Apparent Colors 2.5 The Persistence of the Aristotelian Strand

27 27 28 32

The Cartesian Strand 3.1 Descartes on Light and Vision 3.2 Descartes’s Criticism of the Aristotelian Distinction between True and Apparent Colors 3.3 Descartes’s Criticisms of the Doctrine of Species 3.4 Descartes on Color as the Proper Object of Vision 3.5 The Cartesian Distinction between Primary and Secondary Qualities 3.6 The Cartesian Strand’s Presence 3.7 Interlude: Where We Find Ourselves Now

50 50

34 37

52 58 64 66 69 73

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5

Contents Descartes’s Quandary 4.1 Descartes’s Vacillation 4.2 A Genealogical Explanation for Descartes’s Vacillation 4.3 The Emergence of Dispositionalism 4.4 Philosophical False Friends

85 85 92 95 97

Moving Beyond the Problem of Color Realism 5.1 The Target/Content Distinction 5.2 The Problem with Cartesian Anti-Realism 5.3 The Problem with Oxford Realism 5.4 The Way Out of Descartes’s Quandary 5.5 Conclusion: Against Ahistorical Conceptual Analysis

112 112 116 122 128

Index

139

130

Figures

2.1 3.1 3.2 5.1

Aristotle’s Theory of the Rainbow Descartes’s Theory of the Rainbow Descartes’s Account of the Visual Process The Strip

35 55 62 113

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Preface Disentangling Our Concept of Color

Nietzsche suggests that concepts influenced by history are like ropes held together by the intertwining of strands, rather than by a single strand running through the whole thing. To analyze such concepts is not to find necessary and sufficient conditions for their use but to disentangle the various strands that have become so tightly woven together by the process of historical development that they seem inseparable. Such analysis would take place most effectively in conjunction with historical theorizing, because it is the historical synthesis of strands that hides their separability from view, and it is thus by going back and forth between historical and conceptual considerations that one can hope to make progress in either the history or the conceptual analysis. —Maudemarie Clark, “Nietzsche’s Immoralism and the Concept of Morality” (1994)1

Conceptual analysis too often proceeds under the assumption that concepts can be examined and understood completely apart from their history. This assumption is so widespread, and so entrenched, that it can sometimes be hard to recognize the possibility of an alternative, historicized approach to conceptual analysis, let alone to appreciate that such an alternative approach might be better situated to help us understand the concepts that are at the center of some of our most longstanding and intractable philosophical debates. This book is a case study in historicized conceptual analysis. In it, I argue that our contemporary concept of color is made up of multiple, conflicting strands of thought that have become intertwined only through their historical juxtaposition and interaction, rather than through any “intuitive” or “logical” unity. I have three goals. The first is to challenge the dominance of the widespread project of trying to offer an ahistorical conceptual analysis of our concept of color. If our contemporary concept of color is made up of multiple, conflicting strands, then it is pointless to try to identify a single set of necessary and sufficient conditions for its use. The second is to unravel the philosophical problem of color realism, a problem that we have come to have as the result of the apparent inseparability of these strands.

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We will only make this problem worse if we continue to ignore the extent to which it results from the entanglement of these conflicting strands. The third is to undermine the appeal of a pair of widely held philosophical views about color, Cartesian anti-realism and Oxford realism. These views take themselves to be opponents in the debate over the problem of color realism, but they share a commitment to thinking that the content of our concept of color is ahistorical and unrevisable, that it is “part of a massive central core of human thinking which has no history” (Strawson 1971, 10). Through the genealogy of our concept of color that I offer in this book, I aim to show that this commitment is mistaken, as are philosophical views that rest upon it. Having laid out the positive goals of my book, it will help to clarify two things that I am not trying to do. First, my aim is not to cast doubt upon, or somehow debunk, our ability to think about color. My aim is to understand how the problem of color realism arises, and why it seems so intractable. As the title of the book indicates, the method I adopt is drawn from Nietzsche’s On the Genealogy of Morality. But, in the first instance, I mean only to be inheriting one aspect of Nietzsche’s genealogy, the particular way in which he criticizes “the ageold practice among philosophers . . . [to] think essentially ahistorically” (Nietzsche 1887/1998, 10 [emphasis in original]). The target of Nietzsche’s criticism is a group of “English psychologists” whom we “have to thank for the only attempts so far to produce a history of the genesis of morality” (Nietzsche 1887/1998, 9). Nietzsche’s criticism is that their putatively “historical” method for understanding morality is at bottom ahistorical, in that they tend to focus on one or another aspect of how our concept of morality is now used and then project that aspect onto the origin of the concept. The fundamental problem is that this method leads these “historians” to overlook the ways in which “the cause of the genesis of a thing and its final usefulness, its actual employment and integration into a system of purposes, lie toto caelo apart” (Nietzsche 1887/1998, 50). The problem is not just that these putative “historians” have misdescribed the actual historical development of our moral concepts. The problem is also that their histories rest upon a fundamental misconception of the nature of moral concepts themselves. For example, in offering a history of the moral concept of punishment, these “previous genealogists of morality” have “discover[ed] some ‘purpose’ or other in punishment, for example revenge or deterrence, [and] then innocently place[d] this purpose at the beginning as the causa fiendi of punishment” (Nietzsche 1887/1998, 50). The problem with this origin story is that, as Nietzsche puts it, [T]he concept “punishment” in fact no longer represents a single meaning at all but rather an entire synthesis of “meanings”: the previous history of punishment in general, the history of its exploitation for the most diverse purposes, finally crystalizes into a kind of unity that is

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difficult to dissolve, difficult to analyze and—one must emphasize—is completely and utterly undefinable. (Today it is impossible to say for sure why we actually punish: all concepts in which an entire process is semiotically summarized elude definition; only that which has no history is definable.) (Nietzsche 1887/1998, 53 [emphasis in original]) Underlying the essentially ahistorical attempt to analyze moral concepts that is given by Nietzsche’s “English psychologists” is a philosophical presupposition: the presupposition is that the contemporary meaning or significance of a concept rests upon a single, univocal use that ahistorical conceptual analysis will (supposedly) allow us to discover. As a way of challenging this presupposition, Nietzsche offers a genealogy of the concept of morality, one that aims to disentangle the different strands of thought that have historically become intertwined in it. Nietzsche’s goal, ultimately, is to show that this concept does not admit of a single definition (or, in other words, that it does not consist in a single strand of thought). It is in this sense that my approach is similar to Nietzsche’s. My target is a different group of philosophers, who are attempting to understand a different concept (the concept of color, not morality). And I aim only to disentangle this concept, not to debunk it. My approach is similar to Nietzsche’s, however, in that it involves challenging the age-old philosophical tendency to think essentially ahistorically about conceptual analysis. In the first instance, the philosophers targeted by my critique are those who assume that how we think about color is ahistorically fixed and unrevisable. Like Nietzsche, I argue that attempts to offer ahistorical conceptual analyses of our concepts overlook the ways in which the history of those concepts can involve multiple, intertwined strands of thought. Moreover, like Nietzsche, I argue that contemporary philosophical problems concerning our use of concepts are often the direct result of tensions between these intertwined strands. The second thing I am not trying to do is somehow show that the historicity of thought about color penetrates color experience itself. That is, I am not trying to show that competing views about the nature of color lead the holders of those views to experience colors differently. The question of the precise relationship between cognition and perceptual experience is an interesting and important issue, and color vision has long been at the center of serious studies of this issue, but I do not intend for anything I say in this book to take a stand on it. If we were to get Aristotle, Descartes, J. L. Mackie, and John McDowell into a room together at the same time, we might well find that differences in their linguistic and cultural backgrounds lead to differences in their abilities to discriminate colors, or in the speed and ease with which they learn how to categorize colors, or in their abilities to remember the colors they have seen, or in what colors they ascribe to stereotypical instances of familiar objects, or in their tendencies to exaggerate similarities within color categories and differences between categories. But

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none of these differences in color perception, learning, and memory have anything to do with how they think about the nature of color. Accordingly, for my purposes in this book, it will help to introduce a distinction between first-order and second-order color claims: First-order color claims are claims about what color category one would put the color of something in, or how a particular color looks compares and contrasts with how other colors look. For example, the claim that fire engines are red, or the claim that neon orange looks very different from navy blue, are both first-order color claims. Second-order color claims are claims about the nature of color properties themselves. For example, the claim that “colors are intrinsic, nonrelational properties that exist independently of light and perceivers” is a second-order color claim. My claims about the historicity of color thought are limited to claims about the historicity of second-order color claims. It might well turn out that there is evidence for the historicity of first-order color claims, but I do not intend to be providing any such evidence in this book, and my argument does not presuppose that there is such evidence. It is enough, for my purposes, to show that there is a historicity to different strands of second-order claims about the nature of color, and that this historicity helps us to understand how the problem of color realism arises and why it seems so intractable, as well as why disentangling these strands might allow us to move beyond this problem. Z. A. Los Angeles May 23, 2015 NOTE 1. Clark (1994, 22).

WORKS CITED Clark, Maudemarie. “Nietzsche’s Immoralism and the Concept of Morality.” In Nietzsche, Genealogy, Morality: Essays on Nietzsche’s Genealogy of Morals, edited by Richard Schacht, 15–34. Berkeley: University of California Press, 1994. Nietzsche, Friedrich. On the Genealogy of Morality: A Polemic. Trans. M. Clark and A.J. Swensen. Indianapolis: Hackett Publishing Company, 1998. Strawson, P.F. Individuals: An Essay in Descriptive Metaphysics. London: Routledge, 1971.

Acknowledgments

Writing this book has been a lonely, isolating task. It has been the mental and physical equivalent of the world’s longest layover. My back aches and I am eager to have real time, back-and-forth conversations about the thoughts expressed in it, rather than struggling to articulate these thoughts to a mute laptop, with no sense of whether the words I’m typing succeed at saying anything at all. The sense of isolation that I have felt, however, is belied by a number of very real ways in which this book has been a communal effort. First, I simply would not have been able to write this book were it not for the considerable wealth of work that is now readily available in the history of science and philosophy. In the main body of the text, I make every effort to identify my debts in this regard, but the work of several writers has played such a significant role that I simply must mention them here. Perhaps first and foremost, I am indebted to work in the history of optics by Olivier Darrigol, Henry Guerlac, David Lindberg, Alan Shapiro, and A. Mark Smith. In the history of color science, the work of Robert Crone, Klaas Halbertsma, and J. D. Mollon has been invaluable. And in the history of philosophy, I have benefited considerably from the work of David Clemenson, Gary Hatfield, Theo Meyering, Alison Simmons, and Willem van Hoorn. Second, throughout the entire period of researching and writing this book I was fortunate to have the help of a series of hard-working and astute research assistants, provided by the New School for Social Research. Juan Carlos Gonzalez helped get the citations in order. Amie Zimmer also helped with the citations and took care of getting permission to reprint copyrighted material. Jason Fisette did a considerable amount of research on the nineteenth-century history of color language studies, none of which made its way into this book, but which was crucial in getting me to think about the historicity of thought about color. He also read through portions of the manuscript and gave me useful comments. Jake Browning did an even more considerable amount of research, on everyone from Democritus to Helmholtz, and on everything from the cognitive penetrability of perceptual experience to criteria for individuating the senses. He also read

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through the entire manuscript and gave me insightful, critical comments on every chapter. I could not have written this book without his assistance and feedback. Third, the loneliness of writing this book has been tempered by the support, encouragement, and conversation of a number of colleagues, friends, and relatives. I first presented the core idea of this book at a conference on color at Auburn University organized by Michael Watkins, and I am grateful to his invitation and to the discussion that ensued. C. L. Hardin was also at this conference, and it would be hard to overstate the effect of his subsequent encouragement and feedback. His enthusiasm has consistently helped me to overcome my doubts about the value of attempting to write this book. I do not think this book achieves anything like what I originally hoped it would, but Hardin’s encouragement has made it possible for me to appreciate the truism that it would be better to make the attempt than to give up without trying. Hardin also introduced me to Rolf Kuehni, who provided a copious number of helpful comments on large portions of the manuscript. I also presented the core idea of this book at a conference at the University of Chicago organized by Nicholas Gaskill and Jonathan Schroeder, and I am grateful to their invitation and the discussion that ensued. In particular, I am grateful to conversations at this conference with Jonathan Cohen and David Hilbert. I am pretty sure that they both remain dubious about the philosophical, rather than merely historical, significance of what I say here, but their open-mindedness and willingness to hear me out led me to fully appreciate, for the first time, the genuine possibility of a philosophical community that rests upon nothing more than a shared sense of curiosity about a topic, rather than adherence to any particular set of philosophical dogmas. I am equally indebted to my colleagues at the New School for Social Research for their unhesitating support of this admittedly idiosyncratic project. They have been nothing but encouraging, and I doubt that I would have felt that it was even possible, let alone worthwhile, to write this book if I had been a member of any other department. Simon Critchley’s positive comments on a fellowship application in which I first proposed the idea of this project made me think that it might actually be worth doing, and Jay Bernstein’s enthusiastic reaction to a talk I gave on it confirmed this thought. Dick Bernstein and Dmitri Nikulin both gave helpful comments on parts of the manuscript. Finally, among all of my colleagues in my department, I am especially indebted to Alice Crary for the manifold ways in which she has aided me as a mentor and friend. For comments on the manuscript, in addition to the people already mentioned, I am grateful to Kenny Easwaran, Jay Elliott, Adam Gies, Daniel Harris, Joe Lemelin, and Zach Weinstein. I owe special thanks in this regard to Eliot Michaelson, for his willingness to give multiple rounds of comments on multiple drafts of the material. I am especially indebted to Nat Hansen and Chauncey Maher for their resolute support of this project throughout its annoyingly long period of

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development. There have been many times when the only thing moving this project forward has been their encouragement, and I sometimes wonder whether Joe Gould would have been able to complete his Oral History of Civilization if he had had friends like them. Finally, for the first few years that I worked on this book, I could not help noticing that the overwhelming majority of acknowledgments sections end by thanking a significant other, “without whom completing this book would not have been possible.” I was single at the time, and as the isolation involved in writing risked becoming overwhelming, I began to worry that this phrase was not a mere rhetorical flourish but a genuine necessary condition on finishing a book-length manuscript. Luckily, I had friends like Danielle Roderick and Josh Parkinson, as well as my parents and sister, Jim, Jane, and Kim, who kept the loneliness from becoming crippling. And I had the city of Los Angeles, which served as an effective antidote to the misery of writing. It is all the more ironic, then, that I end this acknowledgments section by thanking my fiancée, Rebecca Childers, for being the most wonderful person I have ever met, and who has made all of this seem just a little bit less important than getting to spend time together with her.

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1

The Problem of Color Realism

THE QUESTION OF COLOR REALISM . . . concerns the question whether any of the properties material objects actually have are identical with those that color experience represents them as having. Realists give an affirmative answer to this question, anti-realists or error-theorists a negative one. —Kathrin Glüer, “Colors without Circles?” (2007)1

In this chapter, I perform a biopsy on the problem of color realism. It concerns the question of whether colors, as we ordinarily conceive of them, really exist. I use this debate to motivate the need for a genealogy of our concept of color. My goal is to show how an exclusive focus on ahistorical conceptual analysis tends to lead to an impoverished understanding of not only how we think, but also why we think the ways we do, about colors. This chapter has five sections. In §1.1, I introduce Cartesian anti-realism, the view that colors, as we ordinarily conceive of them, do not exist.2 In §1.2, I introduce a prominent line of response to Cartesian anti-realism, Oxford realism, which argues against Cartesian anti-realism by rejecting its account of how we ordinarily conceive of colors.3 Underlying the debate between Cartesian anti-realists and Oxford realists is a debate about how, exactly, we ordinarily conceive of colors. Throughout §§1.2–1.4, I explain the contributions that Oxford realists, Cartesian anti-realists, and others have made to this underlying debate. My goal in these sections is to make explicit an assumption structuring their contributions to this debate, an assumption that I take to be emblematic of ahistorical conceptual analysis. I call this assumption the univocality assumption. The univocality assumption holds that an adequate answer to the question, “How do we ordinarily conceive of colors?” must identify a single, univocal, strand of thought. In the final section (§1.5), I argue that if we really want to understand how we think about colors, and to properly appreciate the role that this conception plays in raising the problem of color realism, then we should reject the univocality assumption. Moreover, we should do this not just at the level of how groups think, but also at the level of how individuals think. The rejection of this assumption motivates the need for a genealogy of color because

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it raises the question of how and why we might have come to have a concept of color that involves multiple, conflicting strands of thought.

1.1

CARTESIAN ANTI-REALISM Color Eliminativism is the denial that physical objects have the colours that we attribute to them, in our everyday thought and talk: the visually conspicuous features that we naively and pre-reflectively attribute to physical objects. And Colour Realism (at least, in one form) is the natural opponent for eliminativism, is the denial of this denial. —Barry Maund, “Colour Eliminativism” (2011)4

In this section, I introduce Cartesian anti-realism, the view that “there are no colors, as they are ordinarily conceived” (Maund 2006, 246). I introduce this view by outlining a prominent contemporary argument for it, due to J. L. Mackie and Barry Maund (among others). My goal in this section is to bring out how Mackie’s and Maund’s argument for Cartesian anti-realism explicitly rests upon a claim about how we ordinarily conceive of colors, and implicitly rests upon the univocality assumption. Mackie’s and Maund’s argument has two premises.5 The first premise is a conceptual claim about how we ordinarily conceive of colors.6 It holds that color experience represents colors as being intrinsic properties of objects, properties that exist independently of their relations to light and perceivers. In this respect, Cartesian anti-realists hold that color experience represents colors as ontologically similar to other paradigmatically intrinsic properties of objects, such as shapes. As Mackie puts this point, “our dominant ordinary view gives [colors and shapes] much the same status” (Mackie 1976, 16). In short, the first premise in the argument for Cartesian anti-realism is the conceptual claim that we ordinarily conceive of both shapes and colors as ontologically on par: they are both conceived as intrinsic properties of objects that exist independently of their relations to light and perceivers. The second premise is an ontological claim about what there really is. It holds that modern science has discovered that there is nothing in the world that corresponds to our ordinary concept of color. In this respect, Cartesian anti-realists think colors are decidedly not on par with shapes. As Mackie puts this point, [T]hough science has changed the details of its accounts since the seventeenth century, the broad outlines of its message on this issue have remained the same: the literal ascription of colours as we see colours . . . forms no part of the explanation of what goes on in the physical world in the processes which lead on to our having the sensations

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and perceptions that we have, but, by contrast the features actually used in the construction of such explanations still include spatial position and arrangement and motions (of various sorts) of items most of which are countable at least in principle. (Mackie 1976, 18) In short, the second premise is the ontological claim that modern science has shown that colors and shapes are not ontologically on par, because it has retained an explanatory role for shapes that it has not retained for colors.7 Taken together, these two premises imply that colors, as we ordinarily conceive of them, do not really exist. As Maund puts this conclusion, “the world contains no colours, as traditionally conceived, i.e., as traditionally understood and as represented in perception” (Maund 2006, 248).8 It is in this sense that Cartesian anti-realism explicitly rests upon a claim about how we ordinarily conceive of colors. Cartesian anti-realism implicitly rests upon the univocality assumption insofar as it holds that thought about color is not just sometimes erroneous, but always erroneous, in virtue of a kind of general representational failure that is due to how color perception or color experience itself represents colors. Maund is one of the few Cartesian anti-realists to make this assumption explicit; as he puts it, “our ordinary colour talk is univocal, employing a concept [that refers to a property] that is not instantiated in material bodies” (Maund 2011, 383).

1.2

OXFORD REALISM When Locke said that the secondary qualities were powers in things to produce sensations in us, he stated the facts correctly, but he did not realize that his statement was only an analysis of the plain man’s use of secondary quality adjectives. . . . When in ordinary life we say “The paper isn’t really red,” we always intend to imply that the paper has some other colour as a dispositional property. —William Kneale, “Sensation and the Physical World” (1951)9

In this section, I introduce Oxford realism, a prominent line of response to Cartesian anti-realism. Oxford realism is the view that colors, as we ordinarily conceive of them, exist, but it could just as easily (and perhaps more accurately) be thought of as a kind of anti-anti-realism, insofar as the argument for it is entirely structured around undermining the argument for Cartesian anti-realism. Specifically, Oxford realists critically respond to the argument for Cartesian anti-realism by rejecting the first premise of this argument, claiming instead that how we ordinarily conceive of colors actually accords with the kinds of properties that Cartesian anti-realists themselves take there to be in the world (as spelled out in the second premise of the argument for Cartesian anti-realism). I introduce the argument for

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Oxford realism by looking at two versions of it, due to John McDowell and Gareth Evans. In this section, I have the same goal as the previous section: to bring out how the argument for the position under discussion (in this case, Oxford realism) explicitly rests upon a claim about how we ordinarily conceive of colors and implicitly rests upon the univocality assumption. The argument for Oxford realism begins by accepting the second premise in the argument for Cartesian anti-realism, the claim that “the literal ascription of colours as we see colours . . . forms no part of the explanation of what goes on in the physical world in the processes which lead on to our having the sensations and perceptions that we have” (Mackie 1976, 18). Here is one contemporary Oxford realist, John Hyman, endorsing this second premise: [T]here is no need to accept that colors are qualities that physical objects really possess in order to explain how our experiences of color are produced. . . . [A] sketchy grasp of optics is more than enough to dispose of the idea that we can explain why things appear variously colored to various observers by predicating colors of them. (Hyman 2006, 21–22) And here is McDowell: it is “obvious” that colors “cannot be credited with causal efficacy” (McDowell 1985, 142–143; cf. McGinn 1983, 14–15). Having accepted the second premise in the Cartesian anti-realist argument, Oxford realists go on to reject the first premise, the claim that we ordinarily think of colors and shapes as ontologically similar. They argue against this premise on the grounds that close attention to how we actually ordinarily think about color reveals that we think about color in relational terms, as dispositions to produce certain sorts of visual experiences.10 Here is how Keith Allen summarizes this aspect of the Oxford realist argument (which he himself does not endorse): [P]roponents of this approach claim that the view of colour implicit in common sense is already the view that colours are mind-dependent dispositional properties. . . . [T]his view has proved especially popular at Oxford, where in one form or another it has passed through successive generations of ‘Oxford philosophers.’ (Allen 2007, 137 [emphasis in original])11 Oxford realists propose that close attention to how we actually think about color shows that the first premise in the Cartesian anti-realist argument fundamentally mischaracterizes our ordinary conception. Oxford realists conclude from this that the Cartesian anti-realist argument has not given us any good reason to think that colors do not exist. It is in this roundabout way that they propose to defend color realism. In the rest of this section, I give a more detailed account of two versions of the Oxford realist argument against Cartesian anti-realism: a shorter version due to McDowell and a longer version due to Evans.

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Here is how McDowell puts his critical response to Cartesian anti-realism: According to Mackie [and other Cartesian anti-realists, the] conception of primary qualities that resemble colours as we see them is coherent; that nothing is characterized by such qualities is established by merely empirical argument. But is the idea coherent? This would require two things: first, that colours figure in perceptual experience neutrally, so to speak, rather than as essentially phenomenal qualities of objects, qualities that could not be adequately conceived except in terms of how their possessors would look; and, second, that we command a concept of resemblance that would enable us to construct notions of possible primary qualities out of the idea of resemblance to such elements of experience. The first of these requirements is quite dubious. . . . But even if we try to let it pass, the second requirement seems impossible. (McDowell 1985, 113) As this passage makes clear, McDowell’s response is based upon rejecting the first premise in the argument for Cartesian anti-realism, the claim that we ordinarily conceive of colors as intrinsic properties of objects that are ontologically similar to shapes. McDowell rejects this premise for two related reasons. First, McDowell rejects this premise on the grounds that it involves conceiving of colors “neutrally.” A neutral conception of a property is one that does not make essential reference to any particular way of perceptually experiencing that sort of property. McDowell is dubious of the intelligibility of being able to conceive of colors neutrally because he doubts that we are able to conceive of colors independently of how objects are disposed to look. To see what he might be getting at here, it helps to think about the following difference between our conceptions of shape and colors: it is obvious that we are able to conceive of shapes independently of how they are disposed to look, but it is not obvious what it would be to conceive of colors independently of how they are disposed to look. McDowell seems to think that this difference suffices to cast doubt on the intelligibility of extending a “neutral” conception of properties from the case of shapes to the case of colors.12 Second, McDowell rejects this premise on the grounds that it involves conceiving of colors as the sort of thing that might “resemble” our perceptual experiences of those properties. McDowell is dubious of the intelligibility of this way of conceiving of colors because he doubts that it makes sense to say that any of the properties that causally explain the production of our perceptual experiences might “resemble” our perceptual experiences of those properties. In a footnote, he cites an essay from P. F. Strawson that contains an elaboration of this point: Mackie suggests that there is a genuine resemblance between subjective representation and objective reality as far as shape is concerned; but this

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The Problem of Color Realism suggestion is quite unacceptable. It makes no sense to speak of a phenomenal property as resembling a non-phenomenal, abstract property such as physical shape is conceived to be by scientific realism. (Strawson 2011, 140–141 [emphasis in original])

In short, McDowell is dubious of the coherence of saying that any of our perceptual experiences might “resemble” the properties that causally explain the production of those experiences. For our purposes, the crucial thing to note about both of McDowell’s reasons for rejecting the first premise in the argument for Cartesian anti-realism is that they both aim to show that this premise is incoherent. McDowell’s underlying reason for arguing that this premise is incoherent is that it asks us to think about colors in a way that he thinks is manifestly at odds with the only way we have for thinking about them, which is in dispositional terms. Here is how he puts this conceptual claim about how we ordinarily think of colors: A secondary quality [such as the color red] is a property the ascription of which to an object is not adequately understood except as true, if it is true, in virtue of the object’s disposition to present a certain sort of perceptual appearance: specifically, an appearance characterizable by using a word for the property itself to say how the object perceptually appears. Thus an object’s being red is understood as something that obtains in virtue of the object’s being such as (in certain circumstances) to look, precisely, red. (McDowell 1985, 111) McDowell proposes that thinking about colors just is thinking about how objects are disposed to look. Accordingly, he thinks that it is simply incoherent to propose that we ordinarily conceive of colors in terms that do not essentially involve how objects are disposed to look. Evans’s argument is similar to McDowell’s, but it involves attributing a considerable bit more metaphysical subtlety to how we ordinarily think about colors. This metaphysical subtlety is due in part to the context in which Evans’s argument occurs, as part of an attempt to inherit and revise Strawson’s project of descriptive metaphysics. This is the project of making explicit the “shared and universal conceptual scheme which we human beings have, and know that we have, and for which no justification in terms of more fundamental concepts or claims can be given” (Snowdon 2009, §5). There are three steps to Evans’s argument.13 First, he claims that only some of our experiences of the world allow us to draw a clear distinction between properties of the experience and properties of the object of the experience. This is not just about being able to numerically distinguish the experience from what it is about (when it is not self-referential). It is also about being able to qualitatively distinguish the two: according to Evans, it must be possible for the object of such an

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experience to have properties that are qualitatively distinct from the properties of the experience itself. In short, for Evans, only some of our experiences of the world exhibit this sort of numerical and qualitative duality—such as our experiences of shapes. It is only with regard to such experiences (and not with regard to some of our other experiences, such as our experiences of color or smell) that it is possible to distinguish between the experience and its properties, and what the experience is about and its properties. Second, Evans claims that the duality of these experiences is possible only on the basis of having “an elementary theory” (Evans 1985, 269) about the object of the experience (i.e., what the experience is about). Crucially, for Evans, an elementary theory is not something one can arrive at merely by observing regularities in experience. After all, such regularities might be nothing more than properties of experience itself, and not properties of what the experience is about. As such, an elementary theory is something prior to experience, something that we bring to it in order to distinguish properties of the experience from properties of what the experience is about. Evans does not say much about the structure of such theories, or how we might arrive at them. He does, however, offer an example of such a theory: the theory of “primitive mechanics” (Evans 1985, 269) that we use to make sense of the behavior of physical objects. A grasp of such a theory makes it possible to draw a distinction between cases in which a change in our experience implies a change in the physical object that the experience is about, and cases in which a change in our experience does not imply any such change. In short, for Evans, in order for an experience to be the sort of experience that makes it possible to draw a distinction between properties of the experience and properties of what the experience is about, we must have a way of thinking about the object of the experience that is in some important sense prior to our experience of it (or experiences of it). Third, Evans claims that we have such a theory for primary qualities (such as shape) but not for secondary qualities (such as color). Evans’s support for this third claim is primarily negative: he does not proceed by giving a positive account of what our theory of shape involves, but rather, proceeds by arguing that there cannot be such a theory for color. This is because, according to Evans, how we think about colors is exhausted by our experiences of them. For Evans, there is nothing more to something being a certain color than for it to be disposed to look a certain way. To think that there is more to our conception of color is, for Evans, to be in the grips of an illusion. The illusion is the suggestion that how we ordinarily think about colors has the resources to make sense of what colors are independently of how we experience them. In Evans’s words: “it inevitably involves an attempt to make sense of an exemplification of a property of experience in the absence of any experience” (Evans 1985, 272 [emphasis in original]). To bring out the illusory nature of such an attempt, Evans compares it to “conceiving of a pain which no one feels upon the model of a pain which one does feel” (Evans 1985, 273).

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The third step in Evans’s argument is the one most often emphasized by other advocates of Oxford realism. It is the claim that our ordinary thought about color is exhausted by thinking about how objects are disposed to look. Evans’s formulation of the argument for Oxford realism is valuable because he makes explicit the two preceding steps that lead up to this third step: first, the idea that only some of our experiences of the world allow us to distinguish clearly between properties of the experience and properties of the objects of experience, and, second, that we are able to draw this distinction only if we have a way of thinking about their objects that is in some important sense prior to our experiences of them. Here is how an early representative of Oxford realism expresses the third step of Evans’s argument:14 [Someone who thinks it is coherent to claim that our thoughts about colors exhibit the same kind of duality as our thoughts about shapes] may be challenged to assign any positive predicate to [a color] quality in itself . . . and it will be found he can give none . . . and a further proof that he is under an illusion and can really give none is that if he tries, he can only describe its positive character by reference to the positive character of the sensation which it causes, and can never do anything else; and this either means that there is no quality assignable to the thing except the power of producing the sensation in us, discoverable or implied in our perception. (Wilson 1904/1926, 774 [emphasis in original]) The underlying idea here is that our ordinary thought about colors is exhausted by thinking about how objects are disposed to look. It is for this reason that advocates of Oxford realism think that it is incoherent to suppose that our thoughts about colors exhibit the sort of duality that characterizes, for instance, our thought about shapes. From these three steps, Evans arrives at the same conclusion as McDowell: we must conceive of colors in relational terms, as dispositions to produce characteristic sorts of visual experiences in perceiving subjects. Evans does not assume that this aspect of our ordinary conception is obvious. (He notes, for instance, that it is not part of the meaning of color terms (Evans 1985, 272 fn. 27).) But he nonetheless does think that dispositionalism is built into how we ordinarily think about color. For our purposes, there are two crucial things to note about both McDowell’s and Evans’s arguments for Oxford realism. First, like the argument for Cartesian anti-realism, they explicitly rest upon a claim about how we ordinarily conceive of colors. Second, they implicitly rest upon the univocality assumption. This assumption is most evident in the Oxford realist claim that it is incoherent to suppose that we ordinarily conceive of colors as intrinsic properties of objects that are ontologically similar to shapes (Evans 1985, 273 fn. 30; McDowell 1985, 113) because the only way we have for

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thinking about colors is in terms of how objects are disposed to look (Evans 1985, 228–169; McDowell 1985, 111).

1.3 SURVEY OF CONSIDERATIONS IN SUPPORT OF THE INTRINSIC VIEW Locke . . . was criticized, most famously by Berkeley, for not paying sufficient attention to the claims of common sense. In particular, he was criticized for violating our common sense intuitions about the parity of shape and color, and about what goes on when color is perceived.15 —Janet Levin, “Dispositional Theories of Color and the Claims of Common Sense” (2000)16

As we have seen, at the bottom of the debate between Cartesian anti-realists and Oxford realists is the question of how, exactly, we ordinarily conceive of colors. Oxford realists argue that close attention to how we actually think about color shows that we conceive of colors in relational terms, as dispositions to produce characteristic sorts of visual experiences. In this section, I survey five considerations that have been offered in favor of the alternative view, the intrinsic view, which holds that we ordinarily conceive of colors as intrinsic properties of objects that are ontologically on par with shapes. My goal, as in the previous two sections, is to bring out how all of these considerations implicitly rest upon the univocality assumption. Here are the five considerations.17 The most basic consideration that has been offered in favor of the intrinsic view is that there is a duality to color experience that suffices to think of colors as intrinsic properties of objects. This is a quantitative duality, one that makes it possible to draw a distinction between color experiences and what the color experiences are about. The thought is that this quantitative duality shows that we ordinarily think of color experiences as referring to properties of objects, not to properties of experiences. Here is how Gilbert Harman puts this point: When you think about visual representation, it is very important to distinguish (a) qualities that experience represents the environment as having from (b) qualities of experience by virtue of which it serves as a representation of the environment. When you see a ripe tomato your visual experience represents something as red. The redness is represented as a feature of the tomato, not a feature of your experience. (Harman 1996, 253) This first consideration has been put in many ways: for instance, in terms of the “intentionality”18 of color experience, or its “outer-directed,”19

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“transparent,”20 or “diaphanous”21 character. The basic point is that color experience represents colors as being properties of objects in the world, not properties of experience. The thought is that this puts our experience of colors on par with our experience of shapes. Furthermore, it shows how our experience of colors is manifestly unlike our experience of aches, insofar as our experience of aches does not exhibit this quantitative duality and we do not ordinarily think of aches as being properties of objects in the world outside of our bodies. A second consideration that advocates of the intrinsic view have invoked is that our ordinary experience of color involves color constancy, the ability to identify the colors of objects across changes in the conditions under which we see them.22 This ability suggests that there is a sense in which we perceive the colors of things as something that is constant across changes in how they look to us. For example, if I pass my hand over my computer keyboard right now, the keyboard is cast in a shadow. But this change in how the computer keyboard looks does not make me think that the color of the keyboard itself has changed. Instead, I think of the color as unchanging across this change in my visual experience of it. This implies that I am able to draw a kind of reality/appearance distinction with regard to the color of the keyboard, between its real color and how that color merely appears when it is cast in a shadow. Here is how Keith Allen brings out the relevance of this point for how we ordinarily conceive of colors: To say that colours are mind-independent is to say that colour is one thing, our experience of colour another. As such, Mind-Independence entails a distinction between appearance and reality. Colour constancy is evidence of this appearance-reality distinction. (Allen 2011, 158) In this respect, the perceptual constancy of colour is on all fours with the perceptual constancy of shape and size. (Allen 2007, 145) Allen’s point is that with both shape and color, we do not take just any change in our experience of them to automatically imply a change in them; in this respect, he thinks our experiences of shapes and colors are on par. And, once again, it helps to contrast our experience of colors with our experience of aches. A change in my experience of an ache just is a change in the ache; but a change in my experience of a color—say when it is cast in a shadow—does not, in itself, imply a change in the color. A third consideration is that we teach color words through a process of ostensive definition that presupposes that the properties that the words refer to are properties of objects in the world, not properties of our experiences of those objects. Here is how Joshua Gert puts this point: [I]t is not possible for a teacher to point to the sensations of a language learner in order to teach the language learner which sensations are sensations of red, and which are sensations of green. Rather, someone who

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is teaching colour words to someone else must make use of publicly observable objects. (Gert 2006, 568) In short, the fact that we teach color words by reference to publicly observable objects, rather than by making reference to our experiences of those objects, is thought to suggest that we ordinarily conceive of colors as intrinsic properties of the objects themselves, rather than as dispositional properties. A fourth consideration is a direct attack on the claim that we think of colors as dispositions. This consideration takes the form of arguing that if we thought of colors as dispositions, then we would be unable to imagine colors such as “killer yellow,” a yellow that instantly kills anyone who looks at it before they are able to visually experience it. But since (the consideration holds) we are able to imagine “killer yellow,” then we do not think of colors as dispositions. This consideration is originally due to Saul Kripke, who introduced it in lectures and talks, but it has been developed in articles by Justin Broackes, David Lewis, and Mario Gomez-Torrente (Broackes 1992; Lewis 1997; Gomez-Torrente 2011). Here is how Justin Broackes summarizes this consideration: If . . . we make sense of these cases of killer yellow, it can only be because we have—independently of the dispositional thesis . . . a view on what it takes for something to be yellow. We must have, therefore, a conception of the nature of colours, just as we have a conception of the nature of platinum and of other chemical substances. (Broackes 1992, 444) The underlying thought is that if it is possible to imagine a color such as killer yellow, then we must not think of colors as dispositions to produce visual experiences. This is because killer yellow is a color that cannot produce any visual experiences in anyone, since it kills anyone who looks at it. A fifth consideration is a further attack on the claim that we think of colors as dispositions. It has two parts: first, taking a stand on how we think about dispositions, and, second, arguing that this is not how we think about colors. An early formulation of this attack is due to G. F. Stout: When we . . . think of the books in our library as red, blue, green, and yellow, we think of them as they would appear to us were we there to look at them in ordinary daylight. But we proceed quite otherwise in the case of mere possibilities. When we think of a hayrick as inflammable we do not do so by representing it as if it were actually in flames. When we think of a window pane as brittle we do not represent it as actually being broken. In such a case we consciously distinguish between possibility and its actualisation. We do not lose sight of the possibility as such and mentally substitute the actuality. (Stout 1904, 144)

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This consideration is based upon a general claim about dispositions: when we think about an object having a certain disposition, we think of that disposition as a possibility that is available to the object but not, in the first instance, as something that is actually manifested by it. By contrast, when we think about the color of an ordinary opaque object, like the red color of a book cover, we do not think of it the first instance as a possibility, but as something that is actually manifested by the object. To see this contrast, consider a paradigmatic example of a disposition: something being fragile. When we think about a china vase as being fragile, we think about it as having the possibility of breaking if dropped, but we do not think of it, in the first instance, as actually being broken. When we think of a red book cover, by contrast, we think of it as actually being red. The thought is that this shows that we do not think of the redness of the book cover as a disposition. A related consideration has been introduced by Boghossian and Velleman (1989), Johnston (1992), and McGinn (1996). It takes the form of arguing that there is a way that colors would look if they were dispositions, and that colors do not look that way.23 Here is how Johnston puts this consideration:24 A course of experience as of the steady colors is a course of experience as of light-independent and observer-independent properties, properties simply made evident to appropriately placed perceivers by adequate lighting. Contrast the highlights: a course of experience as of the highlights reveals their relational nature. They change as the observer changes position relative to the light source. They darken markedly as the light source darkens. With sufficiently dim light they disappear while the ordinary colors remain. They wear their light- and observerdependent natures on their face. Thus there is some truth in the oft made suggestion that (steady) colors don’t look like dispositions; to which the natural reply is “Just how would they have to look if they were to look like dispositions?”; to which the correct response is that they would have to look like colored highlights or better, like shifting unsteady colors, e.g. the swirling evanescent colors that one sees on the back of compact discs. (Johnston 1992, 226–227) This consideration is based upon a specific claim about how colors would look if they looked like dispositions: they would look like they manifestly depend upon the lighting conditions and/or the line of sight of the perceiver, in the manner of the shifting, unsteady colors on the backs of compact discs. The thought is that, since the colors of ordinary opaque objects do not look like that, they do not look like dispositions. For our purposes, the crucial thing to note is that all five of these considerations in favor of the intrinsic view rest upon the univocality assumption. The only apparent exception is due to Mark Johnston, insofar as he argues

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that we do think of the shifting, unsteady colors on the backs of compact discs as dispositions, but even Johnston assumes that there can be only a single, univocal way of thinking about the steady colors of things. It is in this sense that the intrinsic view rests upon the univocality assumption.

1.4

EXPERIMENTAL EVIDENCE Philosophers have disagreed about whether [a certain view] coheres with our intuitions—some philosophers reject the . . . view whereas others defend it. Philosophers on both sides have brought sophisticated and subtle moves to bear on the issue. But until recently, what they haven’t systematically done is ask people. —Shaun Nichols, “Folk Concepts and Intuitions” (2004)25

We have now seen that there is considerable disagreement between Cartesian anti-realists, Oxford realists, and others on the question of how we ordinarily conceive of colors. Given that this is a question about how we ordinarily conceive of colors, one way of arriving at an answer presents itself: why not simply survey ordinary people? That is, why not ask ordinary people about how they think about colors, and do so outside of the context of asking them about the problem of color realism (so as to avoid having their responses influenced by whatever views they might have about that problem)? So far, there have been two studies that aim to identify this aspect of how people ordinarily think about color: Cohen and Nichols (2010) and Roberts et al. (2014). One problem with taking these studies to decide this question is worth mentioning upfront: they arrive at conflicting results. Cohen and Nichols claim to find evidence that we ordinarily conceive of colors in relational terms. Roberts et al. claim to find evidence that we ordinarily conceive of colors in non-relational terms. In this section, however, I shall argue that there is a second, more significant, problem with these studies, a problem we have seen before: they rest upon the univocality assumption. This is surprising, for although these surveys deploy a method for studying ordinary thinking about color that is different from that of more traditional philosophical theorizing, these surveys still share a substantive commitment with those traditional approaches. In this section, I summarize these two surveys, with the goal of bringing out the role that the univocality assumption plays in them. Cohen and Nichols (2010) report the results of a survey of 31 undergraduates at the University of California, San Diego. The survey was designed to identify whether these undergraduates think of color and shape as ontologically on par: specifically, whether they think of color and/or shape as relational or non-relational. The survey aimed to do this by asking the undergraduates about what they think about two scenarios involving

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The Problem of Color Realism

observers who disagree about the colors and shapes of objects. Here are the scenarios and the questions they asked about them: Andrew the alien and Harry the human view a ripe tomato in good light, at a distance of 1 meter. Harry says that the ripe tomato is red, while Andrew says that the very same ripe tomato is not red (in fact, he says it is green). Which of the following do you think best characterizes their views? (Check one and give a brief justification for your answer.) 1. The tomato is red, so Harry is right and Andrew is wrong. 2. The tomato is not red, so Andrew is right and Harry is wrong. 3. There is no fact of the matter about unqualified claims like ‘the tomato is red’. Different people have different visual experiences when they look at the same object, and it is not absolutely true or false that the tomato is red. And here is another scenario involving shape properties: Abigail the alien and Harry the human view an ordinary compact disc under good light, at a distance of 1 meter. Harry says that the CD is round, while Abigail says that the very same CD is not round (in fact, she says it is triangular). Which of the following do you think best characterizes their views? (Check one and give a brief justification for your answer.) 1. The CD is round, so Harry is right and Abigail is wrong. 2. The CD is not round, so Abigail is right and Harry is wrong. 3. There is no fact of the matter about unqualified claims like ‘the CD is round’. Different people have different visual experiences when they look at the same object, and it is not absolutely true or false that the CD is round. (Cohen and Nichols 2010, 222) Cohen and Nichols propose that these questions are a good guide to how the undergraduates think about the ontology of color. They hold that, if the undergraduates think there is a fact of the matter as to what shape or color it really is, then that suggests that they think of color or shape (or both) as intrinsic properties of the object; if not, then that suggests that they think of color or shape (or both) as relational properties of objects. Cohen and Nichols found that the undergraduates preferred the relational answer 47% of the time with regard to color but only 30.9% of the time with regard to shape. They take this to be evidence in favor of thinking that we do not ordinarily think of colors and shapes as ontologically on par. That said, however, since a slight majority of the test subjects (53%) thought that there was a fact of the matter in the color case, the survey is hardly univocal evidence in favor of thinking that we ordinarily think of colors as relational. Moreover, the fact that 30.9% of the test subjects reported thinking that there is no fact of the matter about shape further

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complicates interpreting the results of the survey, for at least two reasons. On the one hand, if we take it to be a reliable guide to how the test subjects think, it suggests that a sizeable percentage of them think of shapes and colors as ontologically on par. On the other hand, it casts doubt on whether we should take the survey to be a reliable guide to how the test subjects really do think about the ontology of color and shape, insofar as it seems independently implausible to think that 30.9% of people think that shapes are relational properties of objects. Roberts et al. (2014) report the results of a survey of 129 online respondents. 31 of these respondents had post-graduate training in philosophy (PhilPost), and the remaining 98 had no post-graduate training in philosophy (Non-PhilPost). Their survey was designed to overcome what they take to be methodological problems with Cohen and Nichols’s survey. They argue that Cohen and Nichols’s survey does not adequately distinguish between linguistic, perceptual, and ontological claims about how people ordinarily think about the nature of color and shape. They argue that the specific sentence that Cohen and Nichols use as evidence of relationalist intuitions (namely, the sentence “there is no fact of the matter about unqualified claims like ‘the tomato is red’ ”) could be taken to be a claim about language (and thus an expression of linguistic disagreement), or a claim about perception (and thus an expression of perceptual disagreement), or a claim about ontology (and only in this case an expression of the relational nature of color or shape). Moreover, they point out that agreeing with this sentence could simply be evidence of a reluctance to avoid ascribing blame to either one or the other of the perceivers. As a way of correcting these methodological problems, Roberts et al.’s survey asks a series of preliminary questions about these other issues before asking the target question about ontology. They asked individual respondent about color, or shape, but not both. Here are their scenarios and questions: Disagreement case. Alex and Harry examine an object. Alex and Harry examine the object in typical lighting from the same position. They are both fluent English speakers and have normal eyesight. Harry says that the object is red [or round], while Alex says that the very same object is green [or cube shaped]. After reading either a colour or shape case, participants were asked to evaluate 7 statements on a [L]ikert26 scale with 10 items from disagree to agree: Epistemic. We could find out who is right about the colour [or shape] of the object. Fault. One of them, and possibly both, is at fault for getting the colour [or shape] wrong. Appearance. The object may appear in different ways to Alex and Harry, and so, for all we know, both of them could be correctly reporting how the object appears to them.

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The Problem of Color Realism Meaning. Alex and Harry may only disagree about what the words “red” and “green” [or “round” and “cube shaped”] mean, and so given how they may be individually using the words, they could for all we know both be right about the colour [or shape] of the object. Verbal. People often disagree about what word best describes how an object appears. For example, people often disagree about whether something should be called “red” or “orange” [or “round” or “cube”]. Perceptual. People disagree a lot about what colours [or shapes] things perceptually appear to have. Target. In reality, there is an absolute fact of the matter about the colour [or shape] of the object regardless of how it appears to Alex and Harry and regardless of what they think, say, or do. (Roberts et al. 2014, 7–8)

As these statements make clear, Roberts et al. made a special effort to distinguish statements about ontology from statements about knowledge, blame, phenomenology, meaning, language, and perception. The target statement about ontology is listed last, in order to ensure that participants will not mistake it for any of the other questions. Roberts et al. found that most participants (72.3%) held anti-relationist views about color, and (85.9%) held anti-relationalist views about shape. In the Non-PhilPost, the percentage of respondents who responded similarly to color and shape is even closer (74% color and 84% shape). Roberts et al. conclude from this that there is no significant statistical difference in Non-PhilPost between how they ordinarily think about the ontology of color and shape. It is only among PhilPost that they found a difference (64.7 color and 92.9 shape), and they argue that this difference is not statistically significant given the level of agreement on the Likert scale. Roberts et al. conclude from these findings that most people think of colors and shapes as ontologically on par. Here is how they put this conclusion: [A]s we found that only in PhilPost were participants less antirelationalist about colour than shape, it seems that it is not widely held amongst ordinary people that colours are less objective than shapes. This is of course compatible with colours being less objective than shapes, but it is a reason for caution: The intuitive position seems to be that colours are no less objective than shapes. (Roberts et al. 2014, 13) For our purposes, the crucial thing about these surveys is how both Cohen and Nichols and Roberts et al. interpret their respective results. In both cases, they interpret their results as evidence in favor how everyone, all of the time thinks about color. Here is Cohen and Nichols: [T]he picture that emerges is that, for our participants, colours are somewhere in the middle—less often treated as relational than delicious

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and sweet, but more often treated as relational than square. (Cohen and Nichols 2010, 226). And here is Roberts et al.: We are confident, contrary to Cohen and Nichols, that anti-relationalism about colour is in accordance with our phenomenally-informed, pretheoretic intuitions and so is likely the correct view on colour. (Roberts et al. 2014, 16) The crucial thing is that both Cohen and Nichols and Roberts et al. assume that there is a single way that we ordinarily think about color. This is a surprising assumption to make when interpreting either of their studies, since both studies, by their own lights, found evidence of variation in how people think about color. Neither study, however, concludes that this evidence of variation might actually reflect differences in how we think about color. It is in this sense that they both assume that an adequate answer to the question, “How do we ordinarily conceive of colors?” must take the form of identifying a single, univocal, way of thinking about colors. Neither Cohen and Nichols nor Roberts et al. give any reasons in support of the univocality assumption. However, Roberts et al. do consider, and reject, one possible source of variation in how we might ordinarily think about color. The one possibility that they consider is that their respondents might have been influenced by their own background familiarity with color science. Here is what Roberts et al. have to say about this possibility: The fact that only a small number of participants (5/67) in our pilot explicitly appealed to quasi-scientific views weighs against [thinking that participants’ responses were influenced by such views]. It is possible that the number influenced (perhaps tacitly) by such views was really much higher. However, absent any concrete reason to think that this is the case, we are not worried. It seems plausible that when it comes to something as visual as colour that for most people phenomenology would be the principal influence; when one thinks of a colour it is the phenomenal character of that colour that is foremost before one’s mind. (Roberts et al. 2014, 15–16) Roberts et al. reject the possibility that background familiarity with color science might influence how people ordinarily think about color on the grounds that only a small number of their respondents explicitly invoked scientific considerations in their responses. They are certainly right to demand evidence of this influence from anyone who suggests that it might matter for how we think about color. But it is striking to see how this demand for evidence immediately evaporates when they themselves go on to invoke “the phenomenal character” of color as “the principle influence” on how people

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The Problem of Color Realism

ordinarily think about color. Presumably, if a demand for evidence is legitimate with regard to claims about the influence of color science, it is equally legitimate with regard to claims about the influence of the “phenomenal character” of color. However, Roberts et al. do not provide any evidence whatsoever for the claim that the reason that some of their respondents think of colors as intrinsic properties of objects is because of the influence of “the phenomenal character” of colors. Even worse: the question of evidence for this claim does not even come up. There is, I think, a telling explanation for why Roberts et al. (and many others) have failed to recognize the need for evidence for the widespread claim that “the phenomenal character” of color is “the principle influence” on how people think about color. It is due to a tendency to slide between two different sorts of claims about color, a tendency that is vividly illustrated by this very quotation from Roberts et al. itself. The quotation begins by talking about how we think about color, as such, and rightly demands evidence for supposing that our thoughts about color, as such, may or may not be influenced by background familiarity with color science. But it ends by talking about how we think about a particular color, and then simply assumes that how we think about that particular color will be determined by “the phenomenal character” of our experience of that color. From the beginning to the end of this quotation, therefore, there is a significant slide between two different sorts of claims about color. The slide is between second-order claims about the nature of colors and first-order claims about how colors look. The problem with this slide is that it is much easier to see how first-order color claims about how colors look might be due to nothing more than “the phenomenal character” of looking at colors. It is quite different to claim that second-order color claims about the nature of color, as such, might be due to nothing more than “the phenomenal character” of looking at color, as such.

1.5

THE NEED FOR A GENEALOGY OF COLOR Nietzsche’s understanding of concepts explains why . . . our concepts need clarification. [It is] precisely because they are products of a complicated historical development. Different strands have been tied together into such a tight unity that they seem inseparable and are no longer visible as strands. To analyse or clarify such a concept is to disentangle these strands so that we can see what is actually involved in the concept. History can play a role in analysing a concept because at earlier stages the ‘meanings’ that constitute it are not as tightly woven together and we can still perceive their shifts and rearrangements. —Maudemarie Clark, “Friedrich Nietzsche” (1998)27

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19

The preceding sections might make it seem like I think we should merely reject the univocality assumption at the level of trying to understand how groups think about color. In this fifth and final section, I motivate the need for a genealogy of color by drawing attention to the possible presence of variation within how individuals themselves think about color. That is, I aim to bring out how there is not merely interpersonal variation in thought about color, but intrapersonal variation. It is this sort of variation that I think most clearly brings out the need for a genealogy of color that disentangles these different strands of thought. Consider the following hypothetical scenario, from Edward Averill: [S]uppose that the paints in two pots, A and B, appear to normal humans to be the same shade of yellow in sunlight; and suppose that the paint in pot A reflects only light from the red and green parts of the spectrum and the paint in pot B reflects only light from the yellow and blue parts of the spectrum (the large majority of which will be light from the yellow part of spectrum). A figure is painted on a canvas with paint from pot A, and the background is filled in with paint from pot B. The canvas now appears to be a uniform shade of yellow to normal human beings looking at it in sunlight. . . . [However] if the canvas were placed under a light source that emitted light from the yellow band of the spectrum only it would appear to normal observers to have a black figure on a yellow background. (Averill 1985, 283) Now ask yourself the following question: is this canvas the same color all over, or not? When I ask myself this question, I find that I simultaneously want to give two conflicting answers: I want to say that the canvas is, and is not, the same color all over. As evidence that I am not alone here, consider David Hilbert’s initial response to a similar question about a similar scenario.28 Hilbert first points out how, on the one hand, it seems intuitive to say that the canvas is the same color all over, for the following reason: It seems absurd to suppose that there are differences of color between objects that are not perceivable by normal human perceivers in normal circumstances. (Hilbert 1987, 84–85) Hilbert’s first point is that it seems intuitive to say that the canvas is the same color all over, because denying that intuition would imply the absurd result that what normal human perceivers in normal circumstances see is not a reliable guide to the colors of things. But, on the other hand, Hilbert points out that it also seems intuitive to say that the canvas is not the same color all over, for the following reason: It is important to remember that there is an objective physical difference [between the figure and the background.] Although they appear

20

The Problem of Color Realism to have the same color in normal conditions, they do reflect different percentages of light at some wavelengths. . . . [If we accept the first intuition, then] we are committed to saying that we can see a real difference between the dispositions of objects to reflect light by suffering from illusion as to their colors. We can see that the objects are physically different by mistakenly seeing them as different in color. In fact, the only way we can visually determine this physical difference is by suffering from a visual illusion of color difference. . . . The claim that there are observable physical differences between objects which can only be observed as a result of being wrong about some other property of those objects is highly counter-intuitive. (Hilbert 1987, 90)29

Hilbert’s second point is that it also seems intuitive to say that the canvas is not the same color all over, because denying that intuition would imply the absurd result that seeing the canvas as being differently colored is a visual illusion (i.e., that although this difference in how the paints look reveals a real difference between them, this difference in how they look does not reveal a difference in their colors). This is, I submit, a case in which one and the same person can have conflicting intuitions about the color of something because of conflicting intuitions about the nature of colors, as such. This is, in other words, a case in which one’s first-order color beliefs might be influenced by one’s second-order beliefs about the nature of colors. Importantly, this is not a case in which there is variation in the phenomenology of color experience. (This is not a case of cognitive penetration of color experience.) It is a case in which there appears to be variation in one’s beliefs about the nature of colors themselves. In response to this sort of apparent variation in how we, as individuals, think about the nature of colors, there is, I think, an overwhelming tendency to try to explain it away. We are inclined to think that this sort of variation must be more apparent than real. Rather than immediately try to explain this variation away, however, I think that it is worth considering an alternative approach that has not been sufficiently explored, which is to consider the possibility that this variation is due to conflicting but intertwined strands of thought in how we think about the nature of colors themselves. Perhaps our very concept of color contains distinct strands of thought that have become intertwined to such a degree that they now seem inseparable and are no longer visible as distinct strands. As a way of motivating the idea that this conflict is due to our concept of color, consider how this same example does not seem to provoke conflicting intuitions if we ask questions about light or vision with regard to it. For example, ask yourself the following questions: do both the figure and the background relate to light in the same way? More specifically, do they have the same surface spectral reflectance profiles?30 My own immediate response to both of these questions is a simple and straightforward “No.” Now ask

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21

yourself the following further questions: do the figure and background look the same? Not always. More specifically, do they look the same in sunlight? Yes. Do they look the same in yellow light? No. Even more specifically, are we able to visually discriminate the different surface spectral reflectance profiles of the figure and background when we look at them in the sunlight? No. What about in the yellow light? Yes. The crucial thing to notice is that all of these questions about light and vision seem to admit of simple, straightforward, univocal answers. It is only when I ask myself about the color (or the colors) of the figure and background that I find myself with conflicting intuitions about what to say. If we really want to understand what is going on here, why we find ourselves in this philosophical quandary about color, then I think that we must abandon the assumption that an adequate answer to the question “How do we ordinarily conceive of colors?” must take the form of identifying a single, univocal, way of thinking about colors. Accordingly, for the remainder of this book, I will abandon this assumption. As an alternative way of trying to make sense of why we find ourselves in this philosophical quandary about color, I propose to explore the question of how and why we might have come to have a concept of color that involves multiple, conflicting strands of thought. The method I adopt for exploring this question is genealogical. Through looking at the history of these strands of thought, I think we will be better positioned to disentangle the distinct roles that they now play in how we think about color.

NOTES 1. Glüer (2007, 107 & 109–110). 2. Prominent contemporary advocates of Cartesian anti-realism include Mackie (1976); Boghossian and Velleman (1989); Landesman (1989 and 1993); Maund (1995, 2006, and 2011); Averill (2005); Levine (2006); Pautz (2006). I call this view Cartesian anti-realism because of its origins in Descartes. I discuss these origins in Chapters Three through Five. For now, the following remark from Malebranche will have to suffice: “Only since Descartes do we respond to these confused and indeterminate questions, whether fire is hot, grass green, sugar sweet, and so on, by distinguishing the equivocation of the sensible terms that express them. If by heat, color, flavor, you mean such and such a movement of insensible parts, the fire is hot, grass green, sugar sweet. But if by heat and the other qualities you mean what I feel near fire, what I see when I see grass, and so forth, then fire is not hot at all, nor is grass green, and so forth” (Malebranche 1674–5/1997, 441). 3. Prominent contemporary advocates of Oxford realism include Strawson (1979); Evans (1985); McGinn (1983); McDowell (1985); Wiggins (1987); Hyman (2006). I call this view Oxford realism because of its origin in a series of philosophers at Oxford. Early Oxford realists include John Cook Wilson (1904/26), H.A. Prichard (1906), Gilbert Ryle (1949), and William Kneale (1951), For a partial history of Oxford realism, see Allen (2007). 4. Maund (2011, 363).

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The Problem of Color Realism

5. The following account of their argument is indebted to Miller (2003, 112–115). 6. As Barry Maund puts it, “The first step for a Colour Eliminativist (and for the opposing Colour Realist) is to spell out, in more precise detail, what our ordinary understanding consists in, and what are the properties our ordinary colour names name. Our enquiry thus begins with addressing some conceptual and semantic questions” (Maund 2011, 363). 7. The second step has quite a number of presuppositions of its own. Just to mention two such presuppositions: it presupposes that shapes, as we ordinarily conceive of them, play an explanatory role in science, and that explanatory role is a good indication of something’s ontological status. Both of these presuppositions are quite contentious, but since this chapter is concerned with the role that the Cartesian anti-realism’s first premise plays in its argument, I do not discuss them further here. 8. Here is how Paul Boghossian and David Velleman put this same point: “The best interpretation of colour experience ends up convicting it of widespread and systematic error” (Boghossian and Velleman 1989, 82). And here is Joseph Levine: “Color perception seems to present us with information about the external world—that objects have certain properties—but we can’t find a place for these properties in our theory of the world. . . . There really are no colors” (Levine, 2006, 276). 9. Kneale (1951, 123). 10. John Hyman is not a canonical Oxford realist in this sense, insofar as he argues against dispositionalism (Hyman 2006, 45–56), even though he thinks that “there is an intrinsic tie between color and sentience” (Hyman 2006, 17). But he shares with other Oxford realists the following three core commitments: (i) Cartesian anti-realism is based upon a mischaracterization of how we ordinarily conceive of color (Hyman 2006, 21–6); (ii) this mischaracterization essentially involves overlooking the ways in which we ordinarily conceive of color as essentially involving a relationship between objects, light, and perceivers (Hyman 2006, 15–17); and (iii) how we ordinarily conceive of colors is not historically contingent (Hyman 2006, 19–20 and 2012, 108–109). 11. Maund summarizes this aspect of the Oxford realist argument in similar terms: “These writers are agreed that the correct characterization of the colors of physical objects is in dispositional terms, and in this they are in agreement with Locke and Descartes. Where they differ is in refusing to allow that this dispositional view is anything but a natural one to take. The natural view and the common-sense view is simply the dispositional view” (Maund 1991, 256). 12. I discuss this aspect of McDowell’s argument in more depth in Chapter Five. 13. The following account of Evans’s argument is indebted to Allen (2007). 14. Here are two more expressions of this third step, due to Strawson and Hyman. Here is Strawson: “[Mackie’s account of how we ordinarily conceive of colors] effects a complete logical divorce between a thing’s being red and its being red-looking. Although it is a part of the theory that a thing which is, in itself, red has the power to cause us to seem to see a red thing, the logical divorce between these two properties is absolute. And, as far as I can see, that divorce really produces nonsense. The ascription of colours to things becomes not merely gratuitous, but senseless. Whatever may be the case with shape and position, colours are visibilia or they are nothing” (Strawson 1979, 109 [emphasis added]). And here is Hyman: “I am proposing that the fundamental principle, from which any attempt to explain our basic conception of colors must proceed, is that an object’s color is part of how it looks. Similarly, the smell of a thing is how it smells, and the taste of a thing is how it tastes. I do not want to insist that these principles are self-evident—that is, that everyone

The Problem of Color Realism

15.

16. 17.

18. 19. 20. 21. 22.

23.

23

who understands them will perceive immediately that they are true. For what is self-evident to one person may need to be proved to another. But once they are recognized as true, it will be clear that there is a fundamental difference between an object’s color or smell or taste, on the one hand, and its shape, on the other. For example, if an egg is white and round, then being white is part of its appearance but being round is not. Looking round is part of its appearance—that is, part of how it looks. But being round, as opposed to looking round, is not. Hence, the statement that an object has a certain color already involves the idea of its appearance, in a way that the statement that it has a certain shape does not. So there is an intrinsic tie between color and sentience, as there is between smell or taste and sentience, which does not exist between sentience and shape” (Hyman 2006, 17). An earlier version of this same criticism is due to Margaret Cavendish, from 1666: “For the opinion which holds that all colours are caused by the various reflexion of light, has but a weak and uncertain ground, by reason the refraction or reflexion of light is so inconstant, as it varies and alters continually; and there being so many reflexions and positions of light, if they were the true cause of colours, no colour would appear constantly the same, but change variously, according to the various reflexion of light; whereas, on the contrary, we see that natural and inherent colours continue always the same, let the position and reflexion of light be as it will” (Cavendish 2001, 75). Levin (2000, 151). This survey of considerations is selective. I do not discuss, for instance, Campbell’s claim that our commonsense concept of color involves attributing to colors the sort of causal role that is characteristic of intrinsic properties of objects (Campbell 2006), nor do I discuss Hazlett and Averill’s claim that colors cannot look like dispositions, because (they think) nothing can look like a disposition to look a certain way (Hazlett and Averill 2010). Figures who put the point this way include Harman (1990, 34); Byrne and Hilbert (2003, 52); Holman (2006, 234). Levin (2000, 158) puts the point this way. Figures who put the point this way include McGinn (1996, 541); De Anna (2002, 95); Martin (2002, 378); Tye (2002, 45); Campbell (2005, 105); Byrne (2006, 223); Holman (2006, 230). Figures who put the point this way include Moore (1903, 41); Martin (2002, 378). More specifically, color constancy is the ability to re-identify the color of something even when the intensity or the spectral composition of the illumination conditions change and, therefore, even when the intensity or the spectral composition of the light being reflected by the object changes. For example, a blue bird will reflect primarily 430nm light when it is illuminated by sunlight but it will reflect primarily 570nm light when it is brought inside and illuminated by a tungsten light. Because of color constancy, however, we are able to continue to perceive blue birds as blue even when they are brought inside. This is the case even though something that is outside would be perceived as differently colored if it were to reflect primarily 570nm light. For example, a goldfinch that reflects primarily 570nm light when it is outside will be perceived as yellow. Summing up, color constancy is the ability to perceive a color as constant even across changes in illumination conditions. It is worth noting how this version of the fifth consideration rests upon a significant presupposition that the other version does not. The presupposition is that thinking that colors are dispositions necessarily entails that colors will look like dispositions. I discuss this presupposition at greater length below.

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24. Here is Boghossian and Velleman: “If colours looked like dispositions, however, then they would seem to come on when illuminated, just as a lamp comes on when its switch is flipped. Turning on the light would seem, simultaneously, like turning on the colours; or perhaps it would seem like waking up the colours, just as it is seen to startle the cat. Conversely, when the light was extinguished, the colours would not look as if they were being concealed or shrouded in the ensuing darkness: rather, they would look as if they were becoming dormant, like the cat returning to sleep. But colours do not look like that; or not, at least, to us” (Boghossian and Velleman 1989, 85). And here is McGinn: “[C]olor is perceived as intrinsic to the object, in much the way that shape and size are perceived as intrinsic. No relation to perceivers enters into how the color appears; the color is perceived as wholly on the object, not as somehow straddling the gap between it and the perceiver. Being seen as red is not like being seen as larger than or to the left of. The ‘color envelope’ that delimits an object stops at the object’s spatial boundaries” (McGinn 1996, 541–2). 25. Nichols (2004, 515). 26. A Likert scale asks respondents to rate their responses to questions on a scale, measuring how much they agree or disagree with a particular response. It is designed to measure the intensity of their feelings for particular responses. 27. Clark (1998, 854). 28. Hilbert himself ultimately ends up endorsing only one of these answers, the second. For present purposes, what matters is that he thinks both of these answers seem intuitively appealing. 29. The point is that if we were to go with the other intuition, and hold that the canvas is all the same color, then that would imply that although we are making a mistake when we see it as two colors, that mistake tells us something true, because we are, in fact, seeing a real difference between the figure and the background when we see the them as being different colors. The point is that it is absurd to think that mistakes are a way of getting at the truth. 30. The spectral reflectance profile of a surface is the proportion of incident light that it is disposed to reflect at each wavelength of the visual spectrum.

WORKS CITED Allen, Keith. “The Mind-Independence of Colour.” European Journal of Philosophy 15 (2007): 137–158. ———. “Revelation and the Nature of Colour.” Dialectica 65, no. 2 (2011): 153–176. Averill, Edward W. “Color and the Anthropocentric Problem.” Journal of Philosophy 82 (1985): 281–303. ———. “Toward a Projectivist Account of Color.” The Journal of Philosophy 102, no. 5 (2005): 217–234. Boghossian, Paul and J. David Velleman. “Colour as a Secondary Quality.” Mind 98 (1989): 81–103. ———. “Physicalist Theories of Color.” The Philosophical Review 100 (1991): 67–106. Broackes, Jusin. “The Autonomy of Colour.” In Reduction, Explanation, and Realism, edited by Kathleen Lennon and David Charles, 421–465. Oxford: Oxford University Press, 1992. Byrne, Alex. “Color and the Mind-Body Problem.” Dialectica 60, no. 3 (2006): 223–244.

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Byrne, Alex and David Hilbert. “Color Realism and Color Science.” Behavioral and Brain Sciences 26 (2003): 3–21. Campbell, John. “Transparency vs. Revelation in Color Perception.” Philosophical Topics 33 no. 1 (2005): 105–115. ———. “Manipulating Colour: Pounding an Almond.” In Perceptual Experience, edited by T. Gendler and J. Hawthorne, 38–48. Oxford: Oxford University Press, 2006. Cavendish, Margaret. Observations upon Experimental Philosophy. Edited by Eileen O’Neill. Cambridge: Cambridge University Press, 2001. Clark, Maudemarie. “Friedrich Nietzsche.” In Routledge Encyclopedia of Philosophy, edited by Edward Craig, 844–861. London: Routledge, 1998. Cohen, Jonathan and Shaun Nichols. “Colours, Colour Relationalism and the Deliverances of Introspection.” Analysis 70, no. 2. (2010): 218–228. de Anna, Gabrielle. “The Simple View of Colour and the Reference of Perceptual Terms.” Philosophy 77, no. 299 (2002): 87–108. Evans, Gareth. Collected Papers. Oxford: Oxford University Press, 1985. Gert, Joshua. “A Realistic Colour Realism.” Australasian Journal of Philosophy 84, no. 4 (2006): 565–589. Glüer, Kathrin. “Colors without Circles?” Erkenntnis 66, no. 1–2 (2007): 107–131. Gomez-Torrente, Mario. “Kripke on Color Words and the Primary-Secondary Quality Distinction.” In Saul Kripke, edited by Alan Berger, 290–323. Cambridge: Cambridge University Press, 2011. Harman, Gilbert. “The Intrinsic Quality of Experience.” Philosophical Perspectives 4 (1990): 31–52. ———. “Explaining Objective Color in Terms of Subjective Reactions.” Philosophical Issues 7 (1996): 1–17. Hazlett, Allan and Edward W. Averill. “A Problem for Relational Theories of Color.” Philosophy and Phenomenological Research, 81, no. 1 (2010): 140–145. Hilbert, David. Color and Color Perception. Stanford: CSLI Publications, 1987. Holman, Emmett. “Dualism and Secondary Quality Eliminativism: Putting a New Spin on the Knowledge Argument.” Philosophical Studies 128, no. 2 (2006): 229–256. Hyman, John. The Objective Eye: Color, Form, and Reality in the Theory of Art. Chicago: Chicago University Press, 2006. Hyman, John. “Replies.” Lebenswelt 2, 103–117, 2012. Johnston, Mark. “How to Speak of the Colors.” Philosophical Studies 68 (1992): 221–263. Kneale, William. “Sensation and the Physical World.” Philosophical Quarterly 1 (1951): 109–126. Landesman, Charles. Color and Consciousness: An Essay in Metaphysics. Philadelphia: Temple University Press, 1989. ———. The Eye and the Mind. Norwell, MA: Kluwer, 1993. Levin, J. “Dispositional Theories of Color and the Claims of Common Sense.” Philosophical Studies 100, no. 2 (2000): 151–174. Levine, Janet. “Color and Color Experience: Colors as Ways of Appearing.” Dialectica 60, no. 3 (2006): 269–282. Lewis, David. “Naming the Colours.” Australasian Journal of Philosophy 75, no. 3 (1997): 325–342. McDowell, John. “Values and Secondary Qualities.” In Morality and Objectivity: A Tribute to J.L. Mackie, edited by Ted Honderich, 110–129. London: Routledge & Kegan Paul, 1985. McGinn, Colin. The Subjective View: Secondary Qualities and Indexical Thoughts. Oxford: Clarendon Press, 1983.

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———. “Another Look at Color.” Journal of Philosophy 93, no. 11 (1996): 537–553. Mackie, J.L. Problems from Locke. Oxford: Clarendon Press, 1976. Malebranche, Nicholas. The Search after Truth. Edited and translated by Thomas M. Lennon and Paul J. Olscamp. Cambridge: Cambridge University Press, 1674–5/1997. Martin, M.G.F. “The Transparency of Experience.” Mind & Language 17 (2002): 376–425. Maund, Barry. “The Nature of Color.” History of Philosophy Quarterly 8 (1991): 253–263. ———. Colors: Their Nature and Representation. Cambridge: Cambridge University Press, 1995. ———. “The Illusion Theory of Colours: An Anti-Realist Theory.” Dialectica 60 (2006): 245–268. ———. “Color Eliminativism.” In Primary and Secondary Qualities: The Historical and Ongoing Debate, edited by Laurence Nolan, 362–385. New York: Oxford University Press, 2011. Miller, Alex. An Introduction to Contemporary Metaethics. Cambridge: Polity Press, 2003. Moore, G.E. “The Refutation of Idealism.” Mind 12, no. 48 (1903): 433–453. Nichols, Shaun. “Folk Concepts and Intuitions: From Philosophy to Cognitive Science.” Trends in Cognitive Sciences 8, no. 11 (2004): 514–518. Pautz, Adam. Color Eliminativism. Austin: University of Texas, 2006. Prichard, H.A. “Appearances and Reality.—I.” Mind 15, no. 58 (1906): 223–229. Roberts, Pendaran, James Andow, and Kelly Schmidtke. “Colour Relationalism and the Real Deliverances of Introspection.” Erkenntnis 79, no. 5 (2014): 1173–1189. Ryle, Gilbert. The Concept of Mind. Chicago: University of Chicago Press, 1949. Snowdon, Paul. “Peter Frederick Strawson.” Stanford Encyclopedia of Philosophy, Fall 2009 edition. Accessed April 2, 2015. http://plato.stanford.edu/entries/ strawson/. Stout, G.F. “Primary and Secondary Qualities.” Proceedings of the Aristotelian Society, 4 (1904): 141–160. Strawson, P.F. “Perception and Its Objects.” In Perception and Identity, edited by G. F. MacDonald, 41–60. London: MacMillan, 1979. Strawson, P.F. “Perception and Its Objects.” In Philosophical Writings, 125–145, Oxford: Oxford University Press, 2011. Tye, Michael. “Representationalism and the Transparency of Experience.” Noûs 36, no. 1 (2002): 137–151. Wiggins, David. Needs, Values, Truth. Oxford: Basil Blackwell, 1987. Wilson, J.C. “Primary and Secondary Qualities.” In Statement and Inference Vol. II, edited by A. Farquharson, 764–800. Oxford: Oxford University Press, 1904/1926.

2

The Aristotelian Strand

The object of sight is the visible, and what is visible is colour . . . [C]olour is what lies upon what is in itself visible; ‘in itself’ here means not that visibility is involved in the definition of what thus underlies colour, but that that substratum contains in itself the cause of visibility. Every colour has in it the power to set in movement what is actually transparent; that power constitutes its very nature. That is why it is not visible except with the help of light; it is only in light that the colour of a thing is seen. —Aristotle, On the Soul1

In this chapter, I begin my genealogy by tracing the history of the Aristotelian strand of thought about color. It holds that color is an inherent property of objects that exists independently of light and perceivers. My goal is to make explicit some of the core commitments of this way of thinking about color, in order to show how these commitments persist in how we currently think, as well as how they lay the groundwork for the Cartesian strand’s emergence in opposition to these commitments.2 As a way of spelling out the Aristotelian strand, I draw liberally from both Aristotle’s own writings as well as from those of a number of Scholastic Aristotelians (especially those that were familiar to Descartes and his contemporaries). The Aristotelian strand is, in this sense, a composite. It combines sources in Aristotle’s own writings with lines of inheritance and development in the writings of Scholastic Aristotelians.

2.1

ARISTOTLE ON PERCEPTION Generally, about all perception, we can say that a sense is what has the power of receiving into itself the sensible forms of things without the matter, in the way in which a piece of wax takes on the impress of a signet-ring without the iron or gold. —Aristotle, On the Soul3

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The Aristotelian Strand

At the core of the Aristotelian strand is the general claim that sense organs are able to perceive objects in virtue of being able to take objects’ forms without thereby taking on their matter. This act of taking on the form of an object involves a change or alteration in the sense organ.4 Aristotle understands this change in teleological terms, as the actualization of a potentiality in the sense organ. Each sense organ has the ability to take on a specific sort of form, and the sense organs are individuated in terms of the sort of form that they have the ability to take on. The potentiality of sense organs is, in this sense, limited. As the Scholastic Aristotelian Eustachius puts it, “no faculty can escape the limits of its proper object—vision can perceive only what is visible, hearing what is audible, and so on” (Eustachius 1609/1614, in Ariew et al. [1998, 87]). Perception takes place when a sense organ’s potential to take on its characteristic sort of form is actualized. In the rest of this chapter, I focus on the following three aspects of the Aristotelian strand of thought about color. It is these three aspects that are most directly entangled in the problem of color realism. (§2.2) Color as the Proper Object of Vision (§2.3) The Doctrine of Species (§2.4) The Aristotelian Distinction between True and Apparent Colors

2.2

COLOR AS THE PROPER OBJECT OF VISION In dealing with each of the senses we shall have first to speak of the objects which are perceptible by each. The term ‘object of sense’ covers three kinds of objects, two kinds of which we call perceptible in themselves, while the remaining one is only incidentally perceptible. Of the first two kinds one consists of what is special to a single sense, the other of what is common to any and all of the senses. I call by the name of special object of this or that sense that which cannot be perceived by any other sense than that one and in respect of which no error is possible; in this sense colour is the special object of sight. —Aristotle, On the Soul5

Aristotle introduces color as the proper object of vision. He has two aims in doing so. First, he aims to introduce a distinction between color and two other types of things that we are capable of perceiving through vision, which he refers to as common and incidental objects of vision. Common objects include things like motion, which can be perceived by more than one sense (DA II.6, 418a17–418a19). Incidental objects include things like someone’s social role, which are not directly perceived at all, but which coincide with things that are directly perceived, and can be inferred from them (DA II.6, 418a20–418a25).

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Second, he aims to use color to define vision. For Aristotle, a sense organ is functionally defined in terms of its proper object, the particular sort of quality that it alone is capable of perceiving. Vision is, in this sense, functionally defined as the eye’s ability to see color. Aristotle takes this functional definition quite literally: as he puts it, “when seeing is removed the eye is no longer an eye, except in name—no more than the eye of a statue or of a painted figure” (DA II.1, 412b20–21).6 His point is that the relationship between a sense organ and its proper object is not at all accidental or contingent; it is essential to a sense organ being the sense organ that it is that it be able to perceive its proper object. As Thomas Aquinas puts this aspect of Aristotle’s view, “the essence of each sense and its definition lies in its being naturally suited to be affected by such a sensible. For the defining account of any capacity consists in its relationship to its proper object” (Aquinas c. 1268/1951, in [Pasnau 2000, 29] [emphasis in original]). Importantly, defining vision in terms of color is not the same thing as defining color in terms of vision or holding that the existence or nature of colors in any way depends on vision. With regard to the existence of colors, Aristotle is quite clear that they exist prior to, and independent of, vision. He states that “the perceptible seems to be prior to perception” (Cat 7, 8a6–8, trans. Ackrill) and “the destruction of the perceptible carries perception to destruction, but perception does not carry the perceptible to destruction” (Cat 7, 7b35). With regard to the specific natures of different colors, Aristotle is quite clear that colors are not defined by how they look. Rather, the nature of each color is defined by the specific mixture of ingredients that makes it up. Here is how he puts this point: Colours will thus, too be many in number on account of the fact that the ingredients may be combined with one another in a multitude of ratios; some will be based on determinate numerical ratios, while others again will have as their basis a relation of quantitative excess. (Sens. I.3, 440b18–440b23, trans. Beare)7 For Aristotle, individual colors are defined by these ratios. As Alison Simmons summarizes this point, “[t]o be blue, for example, is not to look a certain way, but to have a certain essence and definition” (Simmons 1994, 118). These two points combine to illustrate the strong sense in which Aristotle is “an unabashed realist about objects of sense” (Broadie 1993, 137).8 Simply put, Aristotle’s realism about colors means that he does not think that the nature or existence of colors depends on being perceived; colors are what they are and exist independently of our perception of them.9 Aristotle’s realism about colors is further illustrated by his account of how the perceptual process takes place. In Myles Burnyeat’s words, the proper objects of perception “are the chief factors in the causal explanation

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of perception” (Burnyeat 1995b 19–20). In the case of visual perception, this process involves three factors: colors, the medium of vision, and the eye. The visual process begins when colors cause an alteration in the medium that stands in between colors and the eye. It is this medium that then causes an alteration in the eye. Aristotle refers to this medium as the transparent, because it is something that is capable of being transparent, such as air, water, or glass. His reason for thinking that there must be such a medium is rather straightforward: If what has colour is placed in immediate contact with the eye, it cannot be seen. Colour sets in movement what is transparent, e.g. the air, and that, extending continuously from the object of the organ, sets the latter in movement. (DA II.7, 419a12–15) For an alteration in this medium to take place, however, the medium must be in a certain state: its potentiality to be transparent must be actualized or, more simply, it must actually be transparent. Light, or illumination, is the actualization of the potentiality of the medium of vision to be transparent. Light is, in this sense, a state of the medium of vision. As Jean De Groot puts this point, “Aristotle treated light solely in relation to its role in visual perception” (De Groot 1991, 21). Illumination/transparency is the state of the medium of vision that makes it possible for us to see the colors of things through this medium. A helpful way of thinking about Aristotle’s conception of light is to think about how we say that children can play outside as long as it is light out.10 In a similar way to which “being light out” makes it possible for children to play outside, Aristotle thinks that “being light out” makes it possible for us to see the colors of things. Significantly, this implies that Aristotle does not hold that color experiences are caused by light. Instead, being illuminated/transparent is the state of the medium of vision that makes it possible for colors to cause color experiences. “Being light out” is the state that the transparent medium must be in in order for it to be possible for colors to be causally efficacious. In Gary Waldman’s words, “Aristotle would, like us, say that one cannot see in the dark because there is no light, but in his theory the inability to see stems from the inability of the medium to transmit the colors of opaque bodies” (Waldman 2002, 3). Accordingly, for Aristotle, light does not play a causal role in the process of color perception. This is because light is not the sort of thing that can play a causal role. As he puts it, “light is neither fire nor any kind whatsoever of body nor an efflux from any kind of body (if it were, it would again itself be a kind of body)” (DA II.7, 418b14–17); or even more simply, “[l]ight or darkness . . . leave bodies quite unaffected” (DA II.12, 424b7–8). Simply put, Aristotle holds that colors cause color experiences, not light.

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Perhaps the clearest way to appreciate how Aristotle is thinking about light here is to note that he does not think it involves any sort of motion whatsoever. As he puts it: Empedocles (and with him all others who use the same forms of expression) was wrong in speaking of light as ‘travelling’ or being at a given moment between the earth and its envelope, its movement being unobservable by us; that view is contrary both to the clear evidence of argument and to the observed facts. (DA II.7, 418b21–24) For Aristotle, rather than involving any form of motion, light is a state of the medium that stands in between the colors of things and our eyes, the state of it actually being transparent, such that we can see the colors of things through it. As Paul Lettinck puts this aspect of Aristotle’s view, “light is not some substance traveling from the light source to the eye or vice versa; it is not a motion, but a certain condition of the transparent, which comes about and disappears instantaneously” (Lettinck 1999, 244). Thus, Aristotle has two related reasons for thinking that colors exist independently of vision. First, colors themselves are required for initiating the causal process that leads to visual perception; i.e., colors, not light, are the causes of visual experiences. Here is how he puts this point: Whatever is visible is colour and colour is what lies upon what is in itself visible; ‘in itself’ here means not that visibility is involved in the definition of what thus underlies colour, but that that substratum contains in itself the cause of visibility. (DA II.7, 418a28–31) Second, sense organs cannot, by themselves, actualize their potentiality to take on their characteristic sorts of forms; they must take on these forms from outside of themselves. For Aristotle, our ability to have experiences of red is, in this sense, dependent upon the independent existence of redness. Here is how he puts this point: For sensation is surely not the sensation of itself, but there is something beyond the sensation, which must be prior to the sensation; for that which moves is prior in nature to that which is moved, and if they are correlative terms, this is no less the case. (Met. IV.5, 1010b30–1011a2, trans. Ross)11 Thus, Aristotle holds that just as there is a necessary connection between being an eye and being able to see colors, there is also a necessary connection between seeing colors and the independent existence of those colors, outside of the eye. In sum: for Aristotle, color, not light, is the proper object of vision, and vision itself is functionally defined as the ability to perceive color. As he

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puts it, “sight is the sight of something . . . in fact it is relative to colour” (Met. V.15, 1021b1–2). Richard Sorabji nicely summarizes this aspect of Aristotle’s view when he points out that, “[o]ne description of colour [that Aristotle gives] is that it is the object of sight, but this is used to define sight, not colour” (Sorabji 2004, 129–130; see also Sorabji 1971).12 2.3

THE DOCTRINE OF SPECIES [A] species intentionalis is called here some formal sign of something which is presented to the senses . . . The species is called ‘intentional’ because the sense by means of the species reaches for the object. For example, when the eye perceives a color in the distance, the philosophers say that a certain similarity of the color itself . . . is received by the eye, i.e., a certain quality which, propagated by the color itself through the medium of air and received by the sense of sight itself, has the power to represent the color itself. —Eustachius of Saint-Paul, A Compendium of Philosophy in Four Parts (1609)13

The doctrine of species is a central part of the Scholastic Aristotelian account of sense perception, with recognizable roots in Aristotle’s own account of the sensory process.14 Scholastic Aristotelians first started using the word “species” in their accounts of sense perception in the thirteenth century, as the result of Latin translations of Arabic translations of Aristotle’s On the Soul. “Species” is a translation of the Greek word “eidos/eidē,” meaning form, shape, or kind (Preus 2007, 96–97).15 The doctrine of species is a way of interpreting Aristotle’s claim that sense perception involves a sense organ “receiving into itself the sensible forms of things without the matter” (DA II.12, 424a18–19 [emphasis added]). Species are the Scholastic Aristotelians’ way of understanding the specific role that forms play in this process, as the causal intermediaries that stand in between an object and a sense organ and make it possible for the sense organ to perceptually represent that object. By the early seventeenth century, the doctrine of species found widespread acceptance by Scholastic Aristotelians.16 It was endorsed in all three of the textbooks on Aristotle that Descartes studied in school, as well as the textbook by Eustachius that Descartes discovered (or possibly rediscovered) later in life and which he described as “the best book ever written” on Scholastic Aristotelian philosophy (CSM III 156).17 The doctrine of species is an elaboration of the role that Aristotle attributes to the medium in the perceptual process. As with Aristotle, the doctrine holds that sense perception begins when a sensible quality of an object alters the medium between the object and the sense organ. Species enter at the next stage, as a way of explaining how the alteration of the medium brings about the alteration of a sense organ. The doctrine holds that when

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a sensible quality alters the medium of perception, it produces something in the medium that resembles that quality without being identical to it. This something is a species. Once this species is produced in the medium it then multiplies, or produces further and further instances of itself, in the medium. This process of producing further and further species is repeated until it brings about an alteration in the sense organ of a perceiver. As with Aristotle, this alteration involves the sense organ taking on the form of the object of perception, without its matter. It is at this point that the sense organ perceptually represents its object. For our purposes, the crucial thing to note about the doctrine of species is that it is a resemblance theory of perceptual representation.18 It is a resemblance theory because it holds that color experiences represent colors in virtue of resembling them. The doctrine is, in this sense, a theory about how it is that color experiences represent, are about, or refer to, anything at all.19 According to this doctrine, color experiences represent their object in virtue of sharing a form with those objects, in virtue of, in this sense, resembling the objects that they represent. Here is how Katherine Tachau summarizes this aspect of the Scholastic Aristotelian view: [It is] precisely insofar as [species] are exact likenesses of their generating objects [that] these images are able to make their objects present to and within the percipient mind, i.e., to represent external reality. . . . [S]pecies are “natural signs (signia naturalia) of their objects. These signs can be distinguished from conventional ones established or, in Baconian terms, “imposed” (imposita) arbitrarily as are the particular significative sounds of particular languages. The distinction lies in the fact that, in contrast to those that signify conventionally (ad placitum), the relation of an intention or species to its generating object is innate, by virtue of their shared nature. (Tachau 1988, 16–18 [emphasis in original]) As Tachau’s summary brings out, the claim that color experiences represent colors in virtue of resembling them is intended to contrast with other, nonresemblance-based forms of representation. Whereas words, for instance, do not represent their objects in virtue of resembling those objects, the Scholastic Aristotelians hold that color experiences do represent their objects in virtue of resembling them. Simmons explains this aspect of the doctrine by saying that “it is their being similitudes that is supposed to account for the referential representationality of sensory experience: it is because it is a similitude of the quality which produced it that a species in my eye makes me see that quality out there” (Simmons 1994, 104–105 [emphasis in original]).20 In sum: the doctrine of species is a resemblance theory of perceptual representation, which holds that color experiences represent colors in virtue of resembling them and which thereby ensures that most color experiences accurately represent their objects.21

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2.4

THE ARISTOTELIAN DISTINCTION BETWEEN TRUE AND APPARENT COLORS [I]t is not necessary for the object to be present in the manner in which it is seen, but only in the manner in which it is capable of impressing a species [on the sense organ]. When the neck of a dove appears to be multi-colored, it is not necessary that the colors be really present to the eye; it is enough that the rays of light act on the neck of the dove in such a way that it is rendered apt for causing the species of these colors. When this happens the exterior sense indeed perceives, in some fashion, an absent thing, namely, the color, for the color is not present. —Francisco Suárez, Commentary on Aristotle’s On the Soul (1575)22

Although Aristotle and the Scholastic Aristotelians think that color experiences are by-and-large veridical, they do not think that these experiences are immune to error. As a way of explaining the possibility of perceptual error with regard to the colors of things, they introduce a distinction between true and apparent colors. This distinction is implicit in Aristotle’s Meteorology,23 becomes explicit in Posidonius’s first-century B.C.E. work in meteorology,24 and runs throughout Scholastic Aristotelian textbooks up to the early seventeenth century.25 The distinction between true and apparent colors is a particular way of thinking about what it would be for something really to be a certain color, as opposed to it merely appearing to be that color. According to this distinction, something really is a certain color if that color inheres in it.26 For example, the blueness of blue jeans is a true color, because it inheres in the jeans. By contrast, the colors we see on the shimmering iridescent necks of doves are apparent colors because they are constantly changing (or disappearing altogether). Followers of Aristotle refer to this second sort of color in many different ways: as apparent, changing, iridescent, transient, emphatical, accidental, phantastical, fugitive, or false. Running throughout all of these ways of referring to apparent colors is a common theme: whereas true colors are really there because they inhere in objects, apparent colors are mere appearances that are not really there because they are (in some sense) due to reflection. The distinction between true and apparent colors has its origins in Aristotle’s theory of the rainbow.27 Perhaps surprisingly for many of us today, Aristotle and many of his followers think that the colors of the rainbow are apparent colors: that is, that they are mere appearances that are not really there. To see why they think this, it will help to spell out some of the specifics of Aristotle’s theory.28 According to Aristotle, when we see rainbows, we are seeing a distorted reflection of the sun, one that produces an optical illusion.29 The reflection we are seeing is off of raindrops, which function as tiny mirrors that reflect

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the color, but not the shape, of the sun. These tiny reflections produce an illusion in two respects. First, like all mirrors, they make it appear as if something is somewhere that it is not. In the case of rainbows, they make it appear as if the sun’s color is somewhere in the sky that it is not. The view that mirrors produce optical illusions in this manner is a mainstay of ancient and medieval optics.30 For example, in Ptolemy’s Optics, mirrors are discussed “primarily as examples of optical illusions—in them, we see objects in places where they really do not exist” (Pendergrast 2003, 64). In the same manner, Aristotle thinks that the tiny mirrors that produce the apparent colors of the rainbow make it appear as if the sun’s color is directly in front of one’s eyes, when in fact it is behind them. The second respect in which these tiny reflections produce an illusion is with regard to the particular colors we see in them, the three apparent bands of red, green, and violet they produce in the sky.31 Since the sun is not actually red, green, and violet, these colors are distorted reflections of the sun’s color, akin to the distorted colors we see in a darkened mirror.32 In sum, for Aristotle, when we see a rainbow, we are seeing a double illusion: we are seeing distorted reflections in front of us of the color of the sun behind us. That Aristotle thinks individual raindrops function as darkened mirrors explains why he thinks the colors that we see in them are mere appearances, but it does not explain why we see different bands of apparent colors in the rainbow. To explain how these different apparent colors are produced, Aristotle proposes that the raindrops that produce the rainbow make up a perfect hemisphere, with the observer at its center (see Figure 2.1, below). The hemisphere has its base on the plane of the horizon, with the observer (O)

Figure 2.1

Aristotle’s Theory of the Rainbow (from Dales 1973, 83)

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in the center of this plane, the sun (S) on the hemisphere directly behind the observer, and the rainbow (E´ to E´´) directly in front. Aristotle uses this mathematical model to explain a number of observable features of the rainbow: its three different bands of apparent color, its apparent shape and location in the sky, and why it appears to move with the observer.33 Aristotle’s explanation for how the three different bands of apparent color are produced is based on the supposition that the distance of an object from one’s eyes weakens one’s ability to see its true color. Here is how he puts this supposition: [W]hen sight is reflected it is weakened and, as it makes dark look darker, so it makes white look less white, changing it and bringing it nearer to black. When the sight is relatively strong the change is to red; the next stage is green, and a further degree of weakness gives violet. (Meteor. III.4, 374b23–27)34 Thus, since the distance from the observer to the sun, via the raindrops, is shortest with regard to the region of the raindrops that make up the uppermost band of the rainbow, the apparent color of this region is red; since the distance from the observer to the sun is slightly further with regard to the middle band, its apparent color is green; and since the distance from the observer to the sun is even further with regard to the lowest band, its apparent color is violet. The apparent shape, location, and movement of the rainbow are all explained by the supposition that the raindrops that produce the rainbow through reflection make up a perfectly smooth hemispheric mirror. As one moves around inside this curved mirror, the apparent location of the rainbow in the sky moves with one. For our purposes, Aristotle’s theory of the rainbow is significant because it provides us with a paradigmatic example of what it would be for something to appear to be a certain color without really being that color. Scholastic Aristotelians inherited this aspect of Aristotle’s theory of the rainbow and its associated distinction between true and apparent colors, with one modification. The modification is that, whereas Aristotle explains apparent colors in terms of the reflection of sight, Scholastic Aristotelians explain them in terms of the reflection of light.35 As Eustachius puts the underlying basis for the contrast between true and apparent colors, some “colors are only apparent, not true and fixed, because they result from the mere reflection of rays” (Eustachius 1614, 235, translated by Jake Browning and Jay Elliott). Or, as Marco Antonio de Dominis puts it, Apart from the actual colours of the bodies remaining in the bodies themselves—no matter what is the cause of their origin—Nature has some colours which are able to change or to be altered. These are called emphatic and apparent and I [de Dominis] am accustomed to call them the bright or gleaming colours. I have no doubt that these colours

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are derived from light, in fact, they are nothing other than light itself. (De Dominis 1611, Chap. 3, p. 9, in Halbersma [1949, 27] [emphasis in original]) For the Scholastic Aristotelians, the distinction between true and apparent colors boils down to a distinction between two different ways in which light relates to the perception of colors: with the perception of true colors, light is involved only in the sense that the medium of vision must actually be illuminated/transparent; with the perception of merely apparent colors, by contrast, light is the cause of the experience itself. Here is how Antonio Rubio explains what is going on when we perceive the merely apparent colors of the rainbow: [I]n the case of the rainbow the eye sees light that appears to it as red, or as some other color—not through a species of color, but through a species of light. Thus the eye sees by an act of vision which is identical to that by which the very same object would be seen if there were no deception. (Rubio 1621, 394, in Hoffman [1996, 367–368], which is revised from Clemenson [2001, 121–122]) It is crucial to note the echo of Aristotle in Rubio’s claim that this appearance is deceptive: the apparent colors of the rainbow (or other apparent colors) are optical illusions because they result from nothing more than reflection. In sum: the distinction between true and apparent colors is a prominent and influential way of drawing a reality/appearance distinction with regard to color experiences. According to this distinction, an object really is the color it appears to be if that color inheres in the object itself, independently of light. An object only appears to be a certain color if that apparent color depends upon light. With experiences of true colors, light is necessary to see them, but the colors themselves exist independently of light. With apparent colors, their very existence depends upon light.

2.5

THE PERSISTENCE OF THE ARISTOTELIAN STRAND The distinction between light and color was universal in early optical thought . . . [I]n Aristotle’s scheme light is not itself visible, but signifies a state of the medium that makes colored bodies on the other side of it visible; color, rather than light, is the “proper object” of sight. —David C. Lindberg, “The Science of Optics: Science in the Middle Ages” (1978)36

At the core of the Aristotelian strand of thought about color is a particular way of thinking about the relationship between color, light, and vision. According to this way of thinking, light makes it possible for us to see the colors of

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things, but the colors of things are themselves independent of light and perceivers. As a way of demonstrating the persistence of the Aristotelian strand in how we think about color, consider the following two intuition pumps.37

Intuition Pump #1 There is a completely dark, windowless closet in your apartment. Sitting on the floor of your closet is a perfectly normal rubber basketball that you never use, because you are a lazy bastard. When you open the door of the closet and turn on the overhead light, the basketball looks orange, just like other rubber basketballs.

Ask yourself the following questions: Q1: Does turning on the overhead light change anything about the basketball? Q2: When you turn on the overhead light and look down at the color of the basketball on the floor, are you thereby seeing the light from the overhead light? In response to Q1, I am inclined to say that turning on the overhead light does not change anything about the basketball. All that it does is make it possible for me to see the color of the basketball, which is something that is there anyway, regardless of whether the light is turned on or off or whether I am looking at it or not. In response to Q2, I am inclined to say that when I turn on the overhead light and look at the basketball, I am not seeing the light from the overhead light. I am just seeing the color of the basketball. If you share these inclinations, then that attests to the presence of the Aristotelian strand in how we think about the relationship between color, light, and vision. We both think that light merely makes it possible for us to see the colors of things. Furthermore, when we look at the colors of things in the light, we are seeing only the colors of things, not the light itself. Colors, in this sense, exist independently of light.

Intuition Pump #2 You are a professional truck driver. You are making a delivery that involves backing your truck down a narrow alley up to a loading dock. In order to see what is behind the truck, you must rely entirely on your side view mirrors. Doing so, you are surprised to see that someone standing on the dock is wearing a Santa Claus suit on top of a Chewbacca costume.

Ask yourself the following questions: Q3: Is the redness that you are seeing a property of the Santa Claus suit? Is it a property of the side view mirror?

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Q4: Do you think the Santa Claus suit will continue to be the same color in the dark that it is in the light? Will the mirror be the same color in the dark that it is in the light? Q5: Do you think that the Santa Claus suit will continue to be the same color if you change your line of sight on it? Will the mirror continue to be the same color if you change your line of sight on it? In response to Q3, I am inclined to say that the redness I am seeing is a property of the Santa Claus suit, but not the mirror. The redness of the suit is merely reflected by the mirror. With Q4, I am inclined to say that the Santa Claus suit will continue to be red in the dark, but the mirror will not continue to be the same color. With Q5, I am inclined to say that the Santa Claus suit will continue to be red even if I change my line of sight, but that the mirror will not continue to be the same color. Once again, if you share these inclinations, then that equally well attests to the continuing presence of the Aristotelian strand in how we think about color, because they imply that there is a fundamental difference between the true redness of the Santa Claus suit, and the merely apparent “redness” of the mirror, in terms of how each relates to light and perceivers. True colors, in this sense, are thought of as independent of light and perceivers.

Evidence For evidence that the Aristotelian strand plays a role in contemporary philosophical debates about color, we need look no further than Mark Johnston’s “How to Speak of the Colors” (1992). In this influential essay, Johnston tries to articulate some of our “core beliefs” about color, beliefs that he thinks define what it is to think about color at all. Here is one such belief (introduced in the previous chapter): A basic phenomenological fact is that we see most of the colors of things as “steady” features of those things, in the sense of features which do not alter as the light alters and as the observer changes position. . . . A course of experience as of the steady colors is a course of experience as of light-independent and observer-independent properties, properties simply made evident to appropriately placed perceivers by adequate lighting. Contrast the highlights: a course of experience as of the highlights reveals their relational nature. They change as the observer changes position relative to the light source. They darken markedly as the light source darkens. With sufficiently dim light they disappear while the ordinary [i.e., “steady”] colors remain. They wear their light- and observer-dependent natures on their face. Thus there is some truth in the oft-made suggestion that (steady) colors don’t look like dispositions; to which the natural reply is “Just how would they have to look if they were to look like dispositions?”; to which the correct response is that they would have to look like colored highlights or better, like shifting,

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In this passage, Johnston introduces a distinction between our experience of “steady” and “unsteady” colors. Johnston claims that steady colors are experienced as existing independently of light and perceivers, whereas unsteady colors are experienced as relational, insofar as “[t]hey change as the observer changes position relative to the light source.” Johnston’s distinction between steady and unsteady colors perfectly parallels the Aristotelian distinction between true and apparent colors. This parallel is perhaps most evident in the example that Johnston uses as an illustration of unsteady colors: namely, the shifting unsteady colors on the back of compact discs. His example of these unsteady colors plays exactly the same role that rainbow colors and the colors on the necks of doves play in the Aristotelian account. In both cases, this sort of example is introduced to bring out a contrast between these apparent colors and the true colors of things, which are thought to exist independently of light and perceivers. His invocation of this example in this context is vivid evidence of the Aristotelian strand’s presence in contemporary philosophical debates about color.

NOTES 1. Arist. DA II.7, 418a26–418b2, trans. Smith. 2. The approach that I take in this book to the history of philosophy and science is idiosyncratic, to say the least. On the one hand, I aim to give a fairly detailed account of some of the specific contributions that Aristotle, Descartes, and their followers have made to how we think about the relationship between light and vision. On the other hand, this account is intended to serve a philosophical function: it is introduced to disentangle the different strands of thought that are intertwined in how we currently think about color, as a step towards showing how the problem of color realism rests upon this entanglement. Given that my historical account has this philosophical function, there are many aspects of Aristotle’s, Descartes’s, and their followers’ views that I do not discuss in any detail. (Most prominently, perhaps, are their contributions to the debate between intromissionist and extramissionist theories of vision.) Furthermore, there are many important exegetical debates about how, exactly, we should read specific aspects of Aristotle’s, Descartes’s, and their followers’ texts that I bracket. My decision not to discuss certain aspects of their views, as well as to bracket certain exegetical debates, is deliberate. I think that if a comparatively small number of historical considerations are highlighted, we will be better situated to see how these specific considerations are entangled in the problem of color realism. 3. Arist. DA II.12, 424a18–21. 4. There is an enormous interpretative debate about how to understand the precise sense in which Aristotle thinks that sense organs take on the forms of the objects they perceive. So-called Literalists think that the sense organ literally comes to have the same qualities as the objects perceived (Slakey 1961; Sorabji 1971, 1972, and 2004; Sisko 1996; Everson 1997). So-called

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5. 6.

7.

8. 9. 10. 11.

12.

13. 14.

15.

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Spiritualists think that this claim should be understood analogically and need not involve any material change (Broadie 1993; Burnyeat 1995a; Witt 1995; Johanson 1997; Esfeld 2000; Murphy 2005). Advocates of a middle-ground (or so-called Broad Church) reading think that perception involves a material change, but one in which the sense organ comes to resemble the object of perception without literally taking on the same quality as it (Lear 1988; Ward 1988; Silverman 1989; Granger 1990 and 1992; Price 1996; Bradshaw 1997; Magee 2000; Caston 2004; Bolton 2005; Lorenz 2008). This book brackets this interpretative debate. Arist. DA II.6, 418a7–14. For discussion of some of the perplexing consequences of this aspect of Aristotle’s hylomorphism, see Ackrill (1972/73). Meyering (1989, 40–45) argues that the continuing influence of this aspect of Aristotle’s view explains why the retinal image was almost universally ignored until Kepler’s pioneering work. As Meyering points out, even in al-Haytham’s (Alhazen) otherwise pioneering account of the visual process, “only the living eye is sensitive to the forms of light and color from the visible object” (Meyering 1989, 41) and any invocations of mechanical forms of image production (such as in a camera obscura) are not intended as literal descriptions of any part of the visual process. Aristotle does not specify what ingredients he is referring to here. Richard Sorabji argues that these ingredients are Aristotle’s four basic elements. As he puts it, “[t]he obvious mixture for [Aristotle] to be referring to is the mixture of the four elements, earth, air, fire, and water, which he describes at such length in the De Generatione et Corruptione. All compound bodies are produced ultimately through the mixture of these elements” (Sorabji 1971, 293). For similar claims about Aristotle’s perceptual realism about colors, see also Silverman (1989, 280); Burnyeat (1995b, 19–20); Everson (1995, 271) and (1997, 126–127); Broakes (1999, 72–80); Code (2008, 12). Broackes (1999) is an insightful discussion of this aspect of Aristotle’s thought about color. I owe this helpful analogy to Jake Browning. Here is Celia Wolf-Devine’s helpful elaboration of this idea: “Our senses must be understood as in potency relative to their objects and can sense only when acted on by those objects, just as the combustible requires the presence of something from outside to make it burn. Otherwise we could sense things at will, which we cannot do” (Wolf-Devine 1993, 12). Here is how Hamlyn and Pasnau make this same point: “[For Aristotle, the] relation between the sense and its object is an essential one . . . That is to say that if we use the sense we must perceive the kind of object in question, since the sense is defined by reference to the kind of object” (Hamlyn 1968, 105). “[T]he proper sensibles are special because of how they make an impression on our senses. Our senses are designed so as to be well suited to detect such objects, and so it is appropriate to define and distinguish those senses in terms of the different objects they are suited to detect” (Pasnau 2000, 30). Eustachius (1609/1614, III 330), in Van Hoorn (1972, 165). For a clear overview of the doctrine of species, see Hatfield (1998) and Simmons (1999, 527–530). For a history of the development of the doctrine, see Lindberg (1976), Tachau (1988), and Spruit (1994). For a detailed account of the doctrine as it was held by the Scholastic Aristotelians of Descartes’s time, see Simmons (1994). For a debate on whether the notion of species is a proper reading of Aristotle by his followers, see Burnyeat (1995a and 1995b) and Sorabji (1995). There is, in this sense, a (merely) terminological similarity between Scholastic Aristotelian accounts of vision and those of ancient atomists, such as

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Empedocles and Democritus, who explained vision in terms of eidola or images that constantly streamed off of objects and flowed to perceivers. For an overview of ancient atomist theories of vision, see Siegel (1959), O’Brien (1970), and Lindberg (1976). For a summary of Aristotle’s and his followers’ criticisms of these theories see Avotins (1980). 16. A caveat is in order: at least 6,653 book-length commentaries on Aristotle were published between 1500 and 1650 (Blum 1988, 141–148). Unsurprisingly, these commentaries are not in complete agreement on the nature of sense perception. The aim of this section on the doctrine of species is to identify, as far as is possible, general points of agreement in the Aristotelian textbooks that were familiar to Descartes. These general points of agreement should not be taken to imply that these textbooks are in complete agreement in all details, or even that everyone writing on Aristotle accepted the doctrine of species. From the very inception of the doctrine of species, there were many critics. For example, Durandus of Saint-Pourçain and William of Ockham were notable dissenters early in the tradition (for discussion of these debates, see Lindberg [1976] and Kraml [2006]). That said, Descartes himself seems to have thought that the differences between Scholastic Aristotelians are mostly superficial, and that he was arguing against aspects of their thought that are shared by all of them. Here is how he puts this point in a letter to Mersenne: I do not think that the diversity of the opinions of the scholastics makes their philosophy difficult to refute. It is easy to overturn the foundations on which they all agree, and once that has been done, all their disagreements over detail will seem foolish. (CSM III 156) 17. In his letters, Descartes mentions studying textbooks on Aristotle by the Coimbrian Commentators, Toletus, and Rubio (CSM III 148). He also mentions discovering Eustachius (CSM III 160). Hatfield (1998, 956) notes that all four of these authors subscribed to the doctrine of species. For a summary of the sort of Aristotelian education that Descartes received at La Flèche, see Garber (1992, 5–9) and Gaukroger (1995, 51–61). For a summary of Descartes’s discovery of Eustachius, see Gaukroger (2002, 32–35) and Edwards (2012, 89–90). For a general account of Descartes’s engagement with Scholastic Aristotelianism, see Ariew (1999 and 2011). For a general overview of the Scholastic Aristotelian textbook tradition, see Schmitt (1988). For a general overview of Scholastic Aristotelianism in the seventeenth century, see Ariew (1998) and Ariew and Gabbey (1998). For a useful reminder of how reading the Scholastics through their critics can grossly distort some of the subtleties of their positions, see Edwards (2007). 18. It is worth noting that all of the Scholastic Aristotelians of Descartes’s time took species to be material forms, unlike many earlier advocates of the doctrine, who took them to be, in some sense, immaterial. This aspect of the history of Scholastic Aristotelian thought is clearly summarized in Gilson (1930, 20–30); Van Hoorn (1972, 164–168); Simmons (1994, 91–103). The early seventeenth-century consensus on the materiality of species is well indicated by Antonio Rubio’s straightforward assertion that “sensible species have corporeal and not spiritual being” (Rubio 1621, 326, in Simmons 1994, 94). 19. For a clear overview of theories of perceptual representation, see Cummins (1991). 20. Here is Gary Hatfield’s gloss on this same point: “[according to the doctrine of species] a kind of identity arises between the sensory power and the object sensed, which identity permits the power to be ‘directed toward’ or ‘attentive of’ the object, and so to cognise it” (Hatfield 1998, 956).

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21. Here is Stuart Clark’s useful summary of this aspect of the doctrine of species: “All the metaphors associated with this process of visual cognition, notably those of mirroring, painting, and the making of impressions in wax, evoke an expectation of representational accuracy. They suggest that the doctrine of visible species was supposed to guarantee visual certainty, give or take the various errors or ‘fallacies’ of vision that were described and explained away in the textbooks on cognition, optics, and ophthalmology. Broadly speaking, the mind had direct access to accurate pictures of the world; the world was what it appeared visually to be” (Clark 2007, 1–2). 22. Suárez (1575/1978, 522–524), in Clemenson (2000, 36). 23. Although commentators on Aristotle commonly take the distinction between true and apparent colors to have its roots in Aristotle’s Meteorology, Aristotle himself does not explicitly introduce and defend any such distinction in that text (or anywhere else in his extant corpus). In the rest of this section, I spell out how the theory of the rainbow that Aristotle introduces in the Meteorology implicitly introduces this distinction. For those interested in the Aristotelian roots of this distinction, however, it is worth noting a comment that Aristotle makes in his debate with Hippocrates and Aeschylus about the color of comets. Hippocrates and Aeschylus thought that the colors of halos and comets are both due to reflection. Aristotle denies that both of these colors are similar, holding instead that “the colour of the halo is due to reflection, whereas in the case of comets the colour is something that appears actually on them” (Meteor. I.7, 344b7–8, trans. Webster). This is as close as I have been able to find of an instance of Aristotle explicitly invoking a distinction between (merely apparent) colors that are due to reflection and (true) colors that inhere in objects. For general histories of the reception of Aristotle’s meteorological writings, see Taub (2003); Heidarzadeh (2008); Martin (2011). 24. The full text of Posidonius’s work in meteorology has been lost, so our only evidence that he articulated and defended the distinction between true and apparent colors is due to Seneca (1963/1971), who argues against Posidonius’s claim that rainbow colors are illusory. For a collection of the extant fragments from Posidonius, see Kidd (1999). 25. For discussion of the history of the true/apparent distinction, see Halbertsma (1949, 22–27); Westfall (1962); Shapiro (1984, 3–5); Guerlac (1986); Boyer (1987, 53); Shea (1991, 211–212); Kemp (1990, 264); Hoffman (1996); Lee and Fraser (2001, 210–211); Crone (1999); Clemenson (2000); Werrett (2001, 143); Atherton (2004, 35–36); Gal and Chen-Morris (2010, 195–196); Darrigol (2012). 26. For Aristotle, the true colors of objects inhere in them in the strong sense that they are the direct result of the mixture of those objects’ ingredients. As he puts it, “when bodies are mixed their colours also are necessarily mixed at the same time; and that this is the real cause determining the existence of a plurality of colours—not superposition or juxtaposition. For when bodies are thus mixed, their resultant colour presents itself as one and the same at all distances alike; not varying as it is seen nearer or farther away” (Sens. I.3, 440b12–17). 27. Here is how Philoponus puts the origins of this distinction: “Aristotle . . . teaches us that some of the processes have substance and are really such as they appear . . . while others are only apparent and are due to optical illusion without being in reality such as they appear, e.g., the rainbow, the halo, rods, mock suns and similar things” Philoponus (2011, 29–30). For general histories of rainbow studies, see Boyer (1987) and Lee and Fraser (2001). For a specific focus on ancient studies, see Sayili (1939), Taub (2003), Johnson (2009), and Stothers (2009). For a focus on seventeenth-century studies, see Sabra (1981).

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28. One significant aspect of Aristotle’s theory of the rainbow that I do not discuss in the main body of the text is the way in which it seems to rest upon a fundamentally different theory of vision than the one offered in On the Soul and Sense and Sensibilia. The difference is that whereas in On the Soul and Sense and Sensibilia Aristotle argues for an intromissionist theory of vision, in the Meteorology he appears to be presupposing an extramissionist theory. This apparent discrepancy has been noted by many commentators on Aristotle, at least as far back as Alexander of Aphrodisias in the third century C.E. Aristotle himself might have been unworried by this discrepancy, insofar as in Generation of Animals he says that “it makes no difference whether we say, as some do, that seeing is caused by the sight going forth from the eye . . . or whether we say that seeing is due to the movement coming from the objects” (GA V.I, 780b33–37, trans. Platt). However, given that the primary cases of vision perception that he discusses in the Meteorology involve optical illusions, there might be a possible explanation for this apparent discrepancy. Perhaps his extramissionist-sounding comments in the Meteorology are more of an attempt to differentiate cases of perceptual error from cases of veridical perception than they are an abandonment of his commitment to an intromissionist theory of vision. For general discussion of why Aristotle might have adopted these two different theories of vision in these two different contexts, see Lindberg (1976, 217 fn. 39) and Johnson (2009, 340–343). 29. For discussion of Aristotle’s theory of the rainbow, see Sayili (1939), Dales (1973, 81–92), Boyer (1987, 37–55), Smith (1999, 149–153), Lee and Fraser (2001, 105–109), Stothers (2009, 30–31), and Wilson (2013, 236–270). 30. For a useful overview history of mirrors, see Gregory (1997, 47–65). For an overview history of philosophers’ views on mirrors, see Pendergrast (2003). Here is how David Lindberg summarizes the significance of the theoretical connection that Aristotle draws between rainbows and mirrors: “Aristotle’s theory of the rainbow leads to a discussion of mirrors, [which] raises what was to become one of the central questions of the science of mirrors [in the ancient and medieval worlds]—whether the image observed in a mirror has an objective existence there or is merely the object itself perceived outside its true place” (Lindberg 1976, 87). 31. Aristotle also thinks that we sometimes see a fourth apparent color in the rainbow, yellow, but that this appearance is even more of an illusion than the other three apparent colors, since it is the result of simultaneous color contrast. As he puts it, “[t]he appearance of yellow [between the red and green bands] is due to contrast; for the red is whitened by its juxtaposition with green” (Meteor. III.4, 375a13–14). 32. Since the mirrors of Aristotle’s time were darker than the mirrors we are familiar with today, this would have been a much more familiar phenomenon for him than it is for us. The Greeks did not have silver-backed glass mirrors; they used highly polished pieces of bronze, silver, and gold as reflective surfaces. See Gulick (1902, 132). 33. Aristotle was not the first to note that the rainbow moves with the observer, nor the first to think that this movement impugned its reality. An associate of Plato’s, Philip, had already noted this, and also used it to argue that rainbows are produced in the same manner as mirror images (which also move with the observer). See Boyer (1987, 37). 34. This is a good example of Aristotle’s apparent commitment to an extramissionist theory of vision, insofar as he explains the optical illusion involved in seeing rainbow colors in terms of sight being weakened by reflection. 35. Once again, this is connected up with the question of Aristotle’s apparent commitment to an extramissionist theory of vision in the Meteorology.

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36. Lindberg (1978, 356). 37. The phrase “intuition pump” is due to Dennett (1988), although I use the phrase in a slightly different sense than Dennett himself.

WORKS CITED Ackrill, John Lloyd. “Aristotle’s Definitions of Psuchê.” Proceedings of the Aristotelian Society 73 (1972/73): 1991–1933. Ariew, Roger. “Aristotelianism in the 17th Century.” In Routledge Encyclopedia of Philosophy Volume 1, edited by Edward Craig, 386–393. London: Routledge, 1998. ———. Descartes and the Last Scholastics. Ithaca: Cornell University Press, 1999. ———. Descartes among the Scholastics. Leiden: Brill, 2011. Ariew, Roger and Alan Gabbey. “The Scholastic Background.” In The Cambridge History of Seventeenth-Century Philosophy, edited by Daniel Garber and Michael Ayers, 425–453. Cambridge: Cambridge University Press, 1998. Aristotle. The Complete Works of Aristotle, edited by J. Barnes. Princeton: Princeton University Press, 1984. Atherton, Margaret. “ ‘Green Is Like Bread’: The Nature of Descartes’ Account of Color Perception.” In Perception and Reality: From Descartes to the Present, edited by Ralph Schumacher, 27–42. Paderborn: Mentis, 2004. Avotins, Ivar. “Alexander of Aphrodisias on Vision in the Atomists.” The Classical Quarterly, New Series, 30 no. 2 (1980): 429–454. Blum, P. R. “Der Standardkursus der katholischen Schulphilosophie im 17. Jahrhundert.” In Aristotelismus und Renaissance–In memoriam Charles B. Schmitt, 127–148, eds. Keßler, Ch. H. Lohr & W. Sparn, Wiesbaden: Otto Harassowitz, 1988. Bolton, Robert. “Perception Naturalized in Aristotle’s De anima.” In Metaphysics, Soul, and Ethics in Ancient Thought: Themes from the Work of Richard Sorabji, edited by Ricardo Salles, 209–244. Oxford: Clarendon, 2005. Boyer, Carl. The Rainbow: From Myth to Mathematics. 2nd ed. Princeton: Princeton University Press, 1987. Bradshaw, David. “Aristotle on Perception: The Dual-Logos Theory.” Apeiron 30, no. 2 (1997): 143–162. Broackes, Justin. “Aristotle, Objectivity and Perception.” Oxford Studies in Ancient Philosophy 17 (1999): 57–113. Broadie, Sarah. “Aristotle’s Perceptual Realism.” The Southern Journal of Philosophy 31 (1993): 137–159. Burnyeat, Miles. “Is an Aristotelian Philosophy of Mind Still Credible? (A Draft).” In Essays on Aristotle’s De anima, edited by Martha Nussbaum and Amélie O. Rorty, 15–26. Oxford: Clarendon Press, 1995a. ———. “How Much Happens When Aristotle Sees Red and Hears Middle C? Remarks on De anima 2.7–8.” In Essays on Aristotle’s De anima, edited by Martha Nussbaum and Amelie O. Rorty, 421–434. Oxford: Clarendon Press, 1995b. Caston, Victor. “The Spirit and the Letter: Aristotle on Perception.” In Metaphysics, Soul, and Ethics in Ancient Thought: Themes from the Work of Richard Sorabji, edited by Ricardo Salles, 245–320. Oxford: Oxford University Press, 2004. Clark, Stuart. Vanities of the Eye: Vision in Early Modern European Culture. Oxford: Oxford University Press, 2007. Clemenson, David. Species, Ideas and Idealism: The Scholastic and Cartesian Background of Berkeley’s Master Argument. PhD dissertation, Rice University, 2000.

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Clemenson, D.L. Species, ideas and idealism: The scholastic and Cartesian background of Berkeley’s master argument. Diss. Rice University, 2001. Code, Alan. “Aristotelian Colors as Causes.” In Festschrift for Julius Moravcsik, edited by Dagfinn Follesdall and John Woods, 235–242. London: College Publications, 2008. Crone, Robert. A History of Color: The Evolution of Theories of Light and Color. Dordrecht: Kluwer, 1999. Cummins, Robert. Meaning and Mental Representation. Cambridge, MA: Bradford Books, 1991. Dales, Richard. The Scientific Achievement of the Middle Ages. Philadelphia: University of Pennsylvania, 1973. Darrigol, Oliver. A History of Optics from Greek Antiquity to the Nineteenth Century. Oxford: Oxford University Press, 2012. De Dominis, Antonius. De radiis visus et lucia in vitris perspectivis et iride. Venice, 1611. De Groot, Jean. Aristotle and Philoponus on Light. New York: Garland Publishing, 1991. Dennett, Daniel. “Quining Qualia.” In Consciousness in Modern Science, edited by A.J. Marcel and E. Bisiach, 42–77. Oxford: Oxford University Press, 1988. Descartes. The Philosophical Writings of Descartes. 3 volumes. Translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch. Volume 3 including Anthony Kenny. Cambridge: Cambridge University Press, 1988. [Abbreviated as CSM.] Edwards, Michael. “Aristotelianism, Descartes, and Hobbes.” Historical Journal 50, no. 2 (2007): 449–464. ———. “Philosophy, Early Modern Intellectual History, and the History of Philosophy.” In The Pursuit of Philosophy: Some Cambridge Perspectives, edited by Alexis Papzoglou, 81–94. West Sussez: Wiley-Blackwell, 2012. Esfeld, Michael. “Aristotle’s Direct Realism in ‘De Anima.’ ” The Review of Metaphysics 54, no. 2 (2000): 321–336. Eustachius a Sancto Paulo. Summa philosophiae quadripartita: de rebus dialecticis, moralibus, phisicis, & metaphysicis. Paris, 1609/1614. Everson, Stephen. “Proper Sensibles and kath'hauta Causes.” Phronesis 40 (1995): 265–292. ———. Aristotle on Perception. Oxford: Oxford University Press, 1997. Gal, Olfer and Raz Chen-Morris. “Baroque Optics and the Disappearance of the Observer: From Kepler’s Optics to Descartes’ Doubt.” Journal of the History of Ideas 71, no. 2 (2010): 191–217. Garber, Daniel. Descartes’ Metaphysical Physics. Chicago: University of Chicago Press, 1992. Gaukroger, Stephen. Descartes: An Intellectual Biography. Oxford: Oxford University Press, 1995. ———. Descartes’ System of Natural Philosophy. Cambridge: Cambridge University Press, 2002. Gilson, Etienne. Études sur le rôle de la pensée médiévale dans la formation du système cartésien. Paris: J. Vrin, 1930. Granger, Herbart. “Aristotle and the Functionalist Debate.” Apeiron 23, no. 1 (1990): 27–50. ———. “Aristotle and Perceptual Realism.” The Southern Journal of Philosophy 31 (1993): 161–171. Gregory, Richard. Mirrors in Mind. Oxford: Spektrurn/New York: W. H. Freeman, 1997. Guerlac, Henry. “Can There Be Colors in the Dark? Physical Color Theory Before Newton.” Journal of the History of Ideas 47, no. 1 (1986): 3–20.

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Gulick, Charles. The Life of the Ancient Greeks: With Special Reference to Athens. New York: D. Appleton and Company, 1902. Halbertsma, K.T.A. A History of the Theory of Colour. Amsterdam: Swets & Zeitlinger, 1949. Hamlyn, David. “Koine Aesthesis.” Monist 52 (1968): 195–209. Hatfield, Gary. “The Cognitive Faculties.” In The Cambridge History of SeventeenthCentury Philosophy. 2 Volumes, edited by Daniel Garber and Michael Ayers, ii, 954–961. Cambridge: Cambridge University Press, 1998. Heidarzadeh, Tofigh. A History of Physical Theories of Comets, from Aristotle to Whipple. Dordrecht: Springer, 2008. Hoffman, Paul. “Descartes on Misrepresentation.” Journal of the History of Philosophy 34 (1996): 357–381. Johanson, T.K. Aristotle on the Sense-Organs. Cambridge: Cambridge University Press, 1997. Johnson, Monte. “The Aristotelian Explanation of the Halo.” Apeiron 42 (2009): 235–358. Johnston, Mark. “How to Speak of the Colors.” Philosophical Studies 68 (1992): 221–263. Kemp, Martin. The Science of Art: Optical Themes in Western Art from Brunelleschi to Seurat. New Haven: Yale University Press, 1990. Kidd, Ian. Posidonius: The Translation of the Fragments, Volume III. Cambridge: Cambridge, 1999. Kraml, Hans. “Why Did Ockham Reject Species?” In Intellect and Imagination in Medieval Philosophy, edited by M.C. Pacheco and J. Meirinhos, 1547–1554. Turnhout: Turnhout Brepols, 2006. Lear, Jonathan. Aristotle: The Desire to Understand. Cambridge: Cambridge University Press, 1988. Lee, Raymond and Alistair Fraser. The Rainbow Bridge: Rainbows in Art, Myth, and Science. University Park: Penn State Press, 2001. Lettinck, Paul. Aristotle’s Meteorology and Its Reception in the Arab World with an Edition and Translation of Ibn Suwar’s Treatise on Meteorological Phenomena and Ibn Bajja’s Commentary on the Meteorology. Leiden/Boston/Koln: Brill, 1999. Lindberg, David. Theories of Vision from al-Kindi to Kepler. Chicago: University of Chicago Press, 1976. Lindberg, David, “The Science of Optics.” In Science in the Middle Ages, 338–68, ed. David C. Lindberg, Chicago: University of Chicago Press, 1978. Lorenz, Hendrik. “The Assimilation of Sense to Sense-Object in Aristotle.” Oxford Studies in Ancient Philosophy 33 (2008): 179–220. Magee, Joseph. “Sense Organs and the Activity of Sensation in Aristotle.” Phronesis: A Journal for Ancient Philosophy 45, no. 4 (2000): 306–330. Martin, Craig. Renaissance Meteorology: Pomponazzi to Descartes. Baltimore: Johns Hopkins University Press, 2011. Meyering, Theo. Historical Roots of Cognitive Science. Boston: Kluwer, 1989. Murphy, Damian. “Aristotle on Why Plants Cannot Perceive.” Oxford Studies in Ancient Philosophy 29 (2005): 295–339. O’Brien, Denis. “The Effect of a Simile: Empedocles’ Theories of Seeing.” Journal of Hellenic Studies 90 (1970): 140–179. Pasnau, Robert. “Sensible Qualities: The Case of Sound.” Journal of the History of Philosophy 38, no. 1 (2000): 27–40. Pendergrast, Mark. Mirror Mirror: A History of the Human Love Affair with Reflection. New York: Basic Books, 2003. Philoponus. On Aristotle Meteorology 1.1–3. Translation with introduction and commentary by Inna Kupreeva. London: Bristol Classical Press, 2011.

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Preus, Anthony. Historical Dictionary of Ancient Greek Philosophy. Maryland: Scarecrow Press, 2007. Price, A.W. “Aristotelian Perceptions.” Proceedings of the Boston Area Colloquium in Ancient Philosophy 12 (1996): 285–309. Rubio, Antonio. Commentarii in libros Aristotelis De Anima. Colonia Agrippina, 1621. Sabra, A.I. Theories of Light from Descartes to Newton. Cambridge: Cambridge University Press Archive, 1981. Sayili, Aydin. “The Aristotelian Explanation of the Rainbow.” Isis 30, no. 1 (1939): 65–83. Schmitt, Charles. “The Rise of the Philosophical Textbook.” In The Cambridge History of Renaissance Philosophy, edited by Charles Schmitt and Quentin Skinner, 792–804. Cambridge: Cambridge, University Press, 1988. Seneca. Naturales Quaestiones, Books 1–3. Translated by Thomas Corcoran. Cambridge, MA: Loeb Classical Library, 1963/1971. Shapiro, Alan E. (Editor). The Optical Papers of Isaac Newton. Volume 1. The Optical Lectures, 1670–1672. Cambridge: Cambridge University Press, 1984. Shea, William R. The Magic of Numbers and Motion: The Scientific Career of René Descartes. Canton, MA: Science History Publications, 1991. Siegel, R.E. “Theories of vision and color perception of Empedocles and Democritus; some similarities to the modern approach.” Bulletin of the History of Medicine XXXIII (1959): 14–159. Silverman, Allan. “Color and Color-Perception in Aristotle’s ‘De Anima.’ ” Ancient Philosophy 9 (1989): 271–292. Simmons, Alison. “Making Sense: The Problem of Phenomenal Qualities in Late Scholastic Aristotelianism and Descartes.” PhD Dissertation, University of Pennsylvania, 1994. ———. “Jesuit Aristotelian Education.” In The Jesuits: Culture, Learning and the Arts, 1540–1773, edited by J.W. O’Malley, S.J. Gauvin Alexander Bailey, Steven J. Harris, and T. Frank Kennedy, 522–537. Toronto: Toronto University Press, 1999. Sisko, John. “Material Alteration and Cognitive Activity in Aristotle’s ‘De Anima.’ ” Phronesis 41, no. 2 (1996): 138–157. Slakey, Thomas. “Aristotle on Sense Perception.” The Philosophical Review 70, no. 4 (1961): 470–484. Smith, A. Mark. Ptolemy and the Foundations of Ancient Mathematical Optics: A Source Based Guided Study. Philadelphia: American Philosophical Society, 1999. Sorabji, Richard. “Aristotle on Demarcating the Five Senses.” The Philosophical Review 80, no. 1 (1971): 55–79. ———. “Aristotle, Mathematics, and Colour.” The Classical Quarterly 22, no. 2 (1972): 293–308. ———. “Intentionality and Physiological Processes: Aristotle’s Theory of Sense Perception.” In Essays on Aristotle’s De anima, edited by Martha Nussbaum and Amélie O. Rorty, 195–225. Oxford: Clarendon Press, 1995. ———. “Aristotle on Colour, Light and Imperceptibles.” Bulletin of the Institute of Classical Studies 47, no. 1 (2004): 129–140. Spruit, Leen. Species Intelligibilis from Perception to Knowledge, Volume 1: Classical Roots and Medieval Discussions. Leiden: E. J. Brill, 1994. Stothers, Richard. “Ancient Meteorological Optics.” The Classical Journal 105 (2009): 27–42. Suárez, Francisco. Suarez commentaria una cum quaestionibus in libros Aristotelis De anima. Edited by Salvador Castellote. 2 vols. Madrid: Editorial Labor, 1575/1978.

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Tachau, Katherine. Vision and Certitude in the Age of Ockham: Optics, Epistemology and the Foundation of Semantics 1250–1345. Boston: Brill Academic Publishing, 1988. Taub, Liba. Ancient Meteorology. London: Routledge, 2003. Van Hoorn, Willem. As Images Unwind: Ancient and Modern Theories of Visual Perception. Amsterdam: University Press of Amsterdam, 1972. Waldman, Gary. Introduction to Light: The Physics of Light, Vision, and Color. New York: Prentice-Hall, 2002. Ward, Jule. “Perception and Logos in De anima ii I 2.” Ancient Philosophy 8 (1988): 217–233. Werrett, Simon. “Wonders Never Cease: Descartes’s Météores and the Rainbow Fountain.” The British Journal for the History of Science 34, no. 2 (2001): 129–147. Westfall, Richard. “The Development of Newton’s Theory of Colour.” Isis 53, no. 3 (1962): 339–358. Wilson, Malcolm. Structure and Method in Aristotle’s Meteorologica: A More Disorderly Nature. Cambridge: Cambridge University Press, 2013. Witt, Charlotte. “Dialectic, Motion, and Perception: De Anima Book 1.” In Essays on Aristotle’s De anima, edited by Martha Nussbaum and Amélie O. Rorty, 27–56. Oxford: Clarendon Press, 1995. Wolf-Devine, Celia. Descartes on Seeing: Epistemology and Visual Perception. Carbondale: Southern Illinois University Press, 1993.

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The Cartesian Strand

[W]hen we say that we perceive colours in objects, this is really just the same as saying that we perceive something in the objects whose nature we do not know, but which produces in us a certain very clear and vivid sensation which we call the sensation of colour. —René Descartes, Principles of Philosophy (1644)1

In this chapter, I continue my genealogy by tracing the history of the Cartesian strand of thought about color. It holds that color experiences do not, in themselves, inform us about their external causes. The Cartesian strand emerges as the result of the discovery that color experiences are produced by the transduction of light by the retina.2 This chapter has two goals. The first is to explain why this discovery raises problems for the Aristotelian strand. The second is to distinguish the different aspects of the Cartesian strand’s critique of the Aristotelian strand. This should help us to resist the tendency to treat the Cartesian critique as a wholesale, indiscriminate rejection of the Aristotelian strand.

3.1

DESCARTES ON LIGHT AND VISION [T]he Peripatetick Schools, though they dispute amongst themselves divers particulars concerning Colours, yet in this they seem Unanimously enough to Agree, that Colours are Inherent and Real Qualities, which the Light doth but Disclose, and not concur to Produce. —Robert Boyle, Experiments and Considerations Touching Colours (1664)3

The Cartesian strand emerges as the result of the discovery that color experiences are produced by the transduction of light by the retina. This discovery implies a fundamentally different relationship between light and vision than that presupposed by the Aristotelian strand. In this chapter, I summarize three Cartesian criticisms of the Aristotelian strand that result from this

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discovery. Before summarizing these three criticisms, it will help to begin with a brief account of Descartes’s views on light and vision.4 Descartes offers several different models for understanding light. In his Optics alone he proposes three different models or “comparisons” for thinking about light: (i) as akin to the vibrations that pass through the cane that a blind man uses to guide himself through the world; (ii) as akin to the pressure in a wine vat that forces wine out of a hole in the bottom of it; (iii) as akin to the speed and direction of a tennis ball as it breaks through a thin fabric (Descartes 2001, 65–83). For our purposes, however, there is one crucial similarity running throughout all of the models Descartes proposes. The crucial similarity is that they all take light to be a type of motion (specifically, a tendency to motion).5 Here is how Descartes puts this thought: Consider light as nothing else, in bodies that we call luminous, than a certain movement or action, very rapid and very lively, which passes toward our eyes through the medium of the air and other transparent bodies. (Descartes 2001, 67) In this respect, Descartes’s conception of light is fundamentally at odds with Aristotle’s conception. For Aristotle, light is not a type of motion; rather, illumination/transparency is the state of the medium of vision that makes it possible for us to see the colors of things through this medium. As David Lindberg puts it, for Aristotle “terms like ‘propagation’ and ‘transmission,’ which imply progressive motion, are not appropriate for describing light” (Lindberg 1976, 8). By contrast, Descartes regards light as a type of motion, one that is itself capable of putting other things into motion.6 Descartes’s views on vision take as their starting point Kepler’s work in optics.7 As Descartes puts it, “I admit that Kepler was my first teacher in optics” (AT III 86 [my translation]). From Kepler, Descartes inherits the idea that the eye is an optical instrument, in which the transparent front part of the eyeball (the crystalline humor) functions as a lens that focuses and inverts the incoming light, projecting it on the inside of the opaque back wall of the eyeball (the retina).8 Kepler himself refuses to give a positive account of what happens beyond this point, thereby implicitly introducing a distinction between the optics of light and the physiology of vision. Here is how Kepler introduces this distinction: How the representation or picture [projected on the retina] is connected to the visual spirits which reside in the retina and in the nerve . . . this I leave to be disputed by the [physiologists]. For the armament of the Opticians does not take them beyond this first opaque wall

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The Cartesian Strand encountered within the eye [i.e., the retina]. (Kepler [1604/1964, 147–148], in Darrigol [2012, 31])

The only thing that Kepler says about what happens beyond this point is that it does not involve light, on the grounds that “this hidden journey, which, since it occurs through opaque and therefore dark places and is brought about by means of spirits which differ totally from humors and other transparent things, already exempts itself entirely from optical laws” (Kepler [1604/1964, 148], in Lindberg [1976, 204]). Descartes agrees with Kepler that light is not involved in the visual process after being transduced by the retina. But Descartes is not as restrained as Kepler, and he proposes an account of the ensuing physiological process. According to Descartes, the transduction of light stimulates the fibers in the optic nerve connected to the retina. The stimulation of these nerves causes the tubules at the opposite ends of these fibers to dilate. The dilation of these nerve endings leads to the release of animal spirits by the pineal gland. Finally, the animal spirits released by the pineal gland flow toward the dilated nerve endings, producing a pattern or “picture” on the surface of the pineal gland. According to our current understanding of the physiology of color vision, virtually every step in Descartes’s account of this process involves serious inaccuracies.9 For the purposes of this chapter, however, the specific inaccuracies of Descartes’s account of what happens after light is transduced by the retina are much less important than the ways in which the discovery that light is transduced by the retina itself raises problems for the Aristotelian strand. The next three sections focus on three criticisms of the Aristotelian strand that result from the discovery that color experiences are produced by the transduction of light by the retina. Specifically, they focus on Descartes’s criticisms of: §3.2: The Aristotelian distinction between true and apparent colors §3.3: The doctrine of species §3.4: Color as the proper object of vision

3.2

DESCARTES’S CRITICISM OF THE ARISTOTELIAN DISTINCTION BETWEEN TRUE AND APPARENT COLORS [S]ince we judge other Sensible Qualities to be True ones, because they are the proper Objects of some or other of our Senses, I see not why Emphatical Colours, being the proper and peculiar Objects of the Organ of Sight, and capable to Affect it as Truly and as Powerfully as other Colours, should be reputed but imaginary ones. —Robert Boyle, Experiments and Considerations Touching Colours (1664)10

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Given that the Aristotelian distinction between true and apparent colors originates in Aristotle’s theory of the rainbow, it is fitting that Descartes’s criticism of this distinction occurs in the context of offering his own theory of the rainbow.11 Descartes’s theory constitutes a landmark moment in the history of rainbow studies, in that it is the first theory to successfully explain many of the most salient observable aspects of rainbows entirely in terms of mathematical laws. As Raymond Lee and Alistair Fraser put it in their history of rainbow studies, “Descartes, despite occasional missteps, did what no one before him could—he clearly laid out a mechanistic, microscopic theory of the rainbow that is still valid and useful today” (Lee and Fraser 2001, 192). The list of observable aspects of rainbows that Descartes’s theory successfully explains is impressive. It explains why rainbows are arched, why the apparent position of a rainbow changes as one’s line of sight on it changes, why both primary and secondary rainbows have consistent locations in the sky (at 42° and 52° angles, respectively), why the order of colors in secondary rainbows is the inverse of the order of colors in primary rainbows, and why the primary rainbow is brighter than the secondary rainbow.12 In addition to successfully explaining these aspects of rainbows, Descartes’s theory also serves as a useful model for how Descartes proposes to arrive at scientific knowledge more generally. As he puts it: The rainbow is such a remarkable phenomenon of nature, and its cause has been so meticulously sought after by inquiring minds throughout the ages, that I could not choose a more appropriate subject for demonstrating how, with the method I am using, we can arrive at knowledge not possessed at all by those whose writings are available to us. (Descartes 2001, 332) As the last clause of this sentence indicates, Descartes takes his theory of the rainbow to be an especially clear example of how he proposes to arrive at the kind of scientific knowledge that his opponents (such as the Scholastic Aristotelians) are not able to achieve. Significantly, this theory is the only concrete example he ever gives of how he thinks we should arrive at this kind of scientific knowledge.13 It is, in this sense, our only illustration of how Descartes thinks we should use mathematical laws to explain physical phenomena. Moreover, as Stephen Gaukroger notes, it is one of the only two examples of mathematical laws being used to explain physical phenomena that was produced in the first half of the seventeenth century—the other being Galileo’s theory of free falling objects (Gaukroger 2006, 382). Descartes arrived at his theory of the rainbow on the basis of a theoretical supposition, but he also drew heavily on empirical investigation and experimentation. The supposition was that, with regard to the mechanical laws that explain their behavior, there is no difference between naturally

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and artificially produced objects. As Descartes put it, “I do not recognize any difference between artefacts and natural bodies except that the operations of artefacts are for the most part performed by mechanisms which are large enough to be easily perceivable by the senses” (CSM I 288). On the basis of this supposition, Descartes went on to investigate how human-made water fountains produced artificial rainbows. (Water fountains were a popular spectacle in palace gardens in sixteenth- and seventeenthcentury Europe.14) He found that the fountains that produce rainbows are fountains that spray water droplets. From this, he concluded that rainbows are produced by individual water droplets. In order to identify exactly how individual water droplets produced rainbows, Descartes built an artificial water droplet, one that was large enough to easily perceive what was going on inside of it (unlike natural water droplets). To do this, he took a large transparent glass sphere, possibly a chamber pot,15 and filled it with rainwater. With his back to the sun, he held the glass sphere in front of him and raised and lowered it while looking into it. He found that when he raised the sphere so that it was at a 42° angle from his eyes, a brilliant red color appeared. When he then slightly lowered the sphere below this 42° angle, it appeared yellow. When he lowered it further, it then appeared blue, and when lowered further still, the others colors of the rainbow appeared. Significantly, the order of colors Descartes observed corresponded exactly to the order of colors of primary rainbows in the sky (and in water fountains). When he raised the sphere above a 42° angle he noted that it did not produce any colors until he reached a 52° angle, at which point it once again appeared red, albeit not as brilliantly as at 42°. Raising the sphere even further, he then observed yellow, then blue and then the other colors of the rainbow. This time the order of colors he observed corresponded exactly to the order of colors in the secondary rainbow—which is the inverse of the series of colors in the primary rainbow. Having identified the angles at which the various colors of the primary and secondary rainbows are produced by the glass sphere (i.e., the artificial water droplet), Descartes went on to examine how the sphere modified16 light in order to produce these various colors. To do this, he investigated what happened to the colors he observed in the sphere when he moved an opaque object around three regions: first, in the region between the sun and the sphere; second, inside the sphere; and, third, in the region between the sphere and his eyes. When he viewed the sphere at a 42° angle and put the opaque object precisely on the line between A and B (see Figure 3.1), he found that the red color disappeared. The red equally well disappeared when he put the opaque object inside the sphere precisely on the line in between B and C; it also disappeared when he put it on the line between C and D; however, the red did not disappear when he put the opaque object anywhere else inside the sphere. Finally, when he put the opaque object precisely on the line between D and E, he once again found that he could not

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see any red in the sphere. By measuring the angles at each of these points, he discovered that the angle at C corresponded to the law of reflection and the angles at B and D corresponded to the law of refraction. This discovery allowed him to offer an explanation in terms of mathematical laws for how colors are produced in the primary rainbow. Descartes then repeated this procedure while viewing the sphere at a 52° angle, once again looking for the different points at which an opaque body prevents the sphere from looking red. Doing so, he arrived at a mathematical explanation for how colors are produced in the secondary rainbow. Here is Descartes’s own summary of what he discovered: [T]he primary rainbow is caused by the rays which reach the eye after two refractions [at B and D] and one reflection [at C], and the secondary by other rays which reach it only after two refractions [at G and K] and two reflections [at H and I]; which is what prevents the second from appearing as clearly as the first. (Descartes 2001, 334)

Figure 3.1

Descartes’s Theory of the Rainbow

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For our purposes, the most significant aspect of Descartes’s theory of the rainbow is the manner in which he goes on to explain how the different bands of color in it are produced. Descartes explains the differences between these bands of colors in terms of the different ways that the physical motion of light ends up being modified by passing through the raindrops. Drawing upon the third of his models of light mentioned above—the tennis ball model—Descartes proposes that each of the colors that we see in the rainbow is a function of the ratio of two dimensions of motion of the invisible tennis ball-like particles that make up the raindrops. These two dimensions of motion are (i) the speed at which the individual balls rotate (around their own axes) and (ii) the speed at which they move forward (in straight lines). As he puts it: [T]he nature of the colors appearing at [a specific point in the rainbow] consists only in the fact that the particles of the fine substance that transmits the action of the light have a stronger tendency to rotate than to move in a straight line; so that those which have a much stronger tendency to rotate cause the color red, and those which have only a slight stronger tendency cause yellow. . . . [G]reen appears where they turn just a little more slowly, and blue where they turn very much more slowly. (Descartes 2001, 337–338) In other words, if the speed of rotation of the tennis ball-like particles is much greater than the speed of the forward motion of these particles, then red is produced; if the speed of rotation is only a little bit greater than the speed of forward motion, then yellow is produced. If the speed of rotation is just a little bit smaller than the forward motion, then green is produced; if it is much smaller, then blue is produced.17 For our purposes, the specifics of this proposal are much less important than the fundamental idea underlying them.18 The fundamental idea is that the different colors of the rainbow are produced by the different ways in which the motion of light is modified by being refracted, reflected, and refracted again by its passage through the raindrops. More specifically, each of these different colors corresponds to a different sort of motion in the particles that make up the raindrops. As Descartes puts it, “Those which have a much stronger tendency to rotate cause the color red and those which have only a slightly stronger tendency cause yellow” (Descartes 2001, 337). In others words, for each of the different colors in the rainbow, there is a different type of motion in the light particles. As A. I. Sabra puts this aspect of Descartes’s view, “In Descartes’ theory the individuality of all colours is strongly suggested by the fact that to each colour on the spectrum there corresponds a definite physical (and, as it happens, periodic) property, the rotational velocity of the corresponding globules [i.e., particles]” (Sabra 1967, 67).

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So far, this is just an explanation of how the colors of the rainbow are produced. What is significant about this explanation is that Descartes goes on to use exactly the same sort of explanation to explain how (what the Scholastic Aristotelians call) the true colors of objects are produced. As he puts it, “it is quite obvious that we should not look for anything else in the colors displayed by other objects” (Descartes 2001, 338).19 Descartes’s reason for thinking that both true and apparent colors are produced in the same way is that light plays the same role in both cases. Simply put, our experiences of both sorts of colors are produced by the transduction of light by the retina. This is why Descartes “cannot approve the distinction made by the philosophers when they say that there are some true colors, and others which are only false or apparent” (Descartes 2001, 338). Here is how Henry Guerlac summarizes this aspect of Descartes’s view: [Descartes] appears as [one of] the earliest modern figure[s] to recognize that light is not merely an auxiliary agent making colors visible to us but the true source of color. He is [one of] the first as well to insist that color is color and to attack the scholastic philosophers for their sharp distinction between “true” colors and those that are merely “apparent,” “false,” or “emphatical,” like the colors of the rainbow. (Guerlac 1986, 13–14 [emphasis in original]) In sum: Descartes rejects the Aristotelian distinction between true and apparent colors on the grounds that it rests upon the false presupposition that light plays a different role in producing our experiences of apparent colors than it plays in the case of producing our experiences of true colors. According to the Aristotelian strand, only experiences of apparent colors are produced by light, and it is because of this that these experiences are mere appearances. Descartes’s radical proposal is that the experiences of both true and apparent colors are brought about by the transduction of light by the retina. This proposal fundamentally undermines the Aristotelian distinction between true and apparent colors and, along with it, the Aristotelian strand’s means for drawing an appearance/reality distinction with regard to color experiences. (Descartes’s own alternative appearance/ reality distinction with regard to colors will be introduced below.) Significantly, among figures working in the seventeenth century, Descartes was not alone in rejecting the Aristotelian distinction between true and apparent colors. The list of other such figures includes Kepler, Beeckman, Gassendi, Grimaldi, De La Chambre, Boyle, and Charleton.20 Running throughout their shared rejection of the Aristotelian distinction is a common theme: the Aristotelian distinction misconstrues the role that light plays in producing color experiences. Experiences of both true and apparent colors are produced by the transduction of light by the retina.

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3.3

DESCARTES’S CRITICISMS OF THE DOCTRINE OF SPECIES For example, when I see a stick, it should not be supposed that certain ‘intentional forms’ [species] fly off the stick towards the eye, but simply that rays of light are reflected off the stick and set certain movements in the optic nerve and via the optic nerve in the brain, as I have explained at some length in the Optics. —René Descartes, Meditations on First Philosophy (1641)21

Descartes’s attitude toward the doctrine of species is dismissive, to say the least. At one point he even sarcastically refers to species as “those small images flitting through the air” that “worry the imagination of the philosophers” (Descartes 2001, 68). Underlying his dismissiveness, however, is a serious pair of criticisms, both of which attack the doctrine on the grounds that it is superfluous. The first criticism argues that the doctrine is not needed to explain the causes of color experiences. The second criticism argues that the doctrine is not needed to explain how color experiences represent colors. Descartes thinks that if he can show that the doctrine is not needed to explain these aspects of sense perception, he will have undermined its appeal altogether.22 In order to spell out Descartes’s two criticisms of the doctrine of species, it will help to being by giving a step-by-step outline of the stages in Descartes’s account of the visual process. For example, here are the stages involved in the case of someone seeing the color of a pair of blue jeans in the sun: 1. External distal cause: the rotating particles in the sun, which have an equal ratio of rotation to forward motion. 2. External intermediate cause1: the straight line of rotating particles in the medium that stands in between the sun and the jeans, which have the same equal ratio of rotation to forward motion as the rotating particles in the sun. 3. External intermediate cause2: the texture of the surface of the jeans, which modifies the incoming motion of light from the sun, resulting in a motion that has a low ratio of rotation to forward motion. 4. External intermediate cause3: the straight line of rotating particles in the medium that stands in between the jeans and the eye, which has a low ratio of rotation to forward motion. 5. Proximal cause: the absorption by the retina of the motion of the rotating particles in the transparent medium, which involves particles in the retina taking on a low ratio of rotation to forward motion (the same ratio that is in the medium between the jeans and the retina).23 6. Internal intermediate cause1: the motion of the optic nerve, which does not involve the same low ratio of rotation to forward motion as

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the particles in the retina. Descartes, following Kepler, does not think that light is involved in the visual process at this stage or beyond it. 7. Internal intermediate cause2: the dilation of the tubules at the end of the optic nerve. 8. Internal effect: the pattern (or “picture”) of animal spirits released by the pineal gland as they flow out towards the dilating tubules on the surface of the brain.

Descartes’s First Criticism of the Doctrine of Species Descartes’s first criticism of the doctrine of species focuses on whether species are the best explanation for how perceivers are in perceptual contact with the objects of perception. According to the doctrine, two separate and independent factors are required for visual contact with the colors of things. First, the transparency of the medium of vision must be actualized by being illuminated by light. Second, the colors of objects must produce species in this transparent medium, and these species must be multiplied through the medium until they inform the sense organs of perceivers. As Descartes notes in the quotation at the beginning of this section, however, these two separate factors are not needed to explain how perceivers are in visual contact with the colors of things: the motion of light suffices to explain how this is possible. Using the technical terms just introduced, the motion of light suffices to explain the entire causal chain from the distal cause through to the proximal cause, via the medium. Accordingly, Descartes concludes that the central explanatory posit of the doctrine of species—the multiplication of species through the medium—is completely superfluous. As he puts it, “that there is no need to assume that something material passes from the objects to our eyes to make us see colors and light, nor even that there is anything in these objects which is similar to the ideas or the sensations that we have of them” (Descartes 2001, 68).24 It is unnecessary because “nothing reaches our mind from external objects through the sense organs beyond certain corporeal motions” (CSM I 304). Here is how Ann MacKenzie puts this first criticism of the doctrine of species: Descartes’ specifically scientific objection to the bogus causal story generated by tradition is that it blocks scientific understanding of every aspect of the sensory process. It cannot explain how images are formed by physical objects, or how they are transmitted through the medium, or received by the sense organ, or transmitted to the brain. (MacKenzie 1990, 136)

Descartes’s Second Criticism of the Doctrine of Species Descartes’s second criticism of the doctrine of species focuses on whether resemblance is the best explanation for how color experiences represent

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colors. According to the doctrine, perceptual experiences represent their objects in virtue of resembling them. Descartes simply rejects this aspect of the doctrine—the idea that perceptual representation is best explained in terms of resemblance—and holds instead a no-resemblance theory of perceptual representation, according to which perceptual experiences do not represent their objects in virtue of resembling them.25 Descartes begins his criticism of this aspect of the doctrine by pointing out that it would be a mistake to assume that perceptual representations must resemble their objects in order to represent them, because there are many representations that do not involve resemblance. Here is how he makes this point: Words . . . bear no resemblance to the things they signify, and yet they make us think of these things, frequently even without our paying attention to the sound of the words or to their syllables. Thus it may happen that we hear an utterance whose meaning we understand perfectly well, but afterwards we cannot say in what language it was spoken. (CSM I 81) In itself, this is not much of a criticism of the doctrine of species. After all, the doctrine itself holds that words are “conventional” representations that need not resemble what they represent, and that it is precisely in this respect that words differ from “natural” representations such as perceptual experiences. Accordingly, the doctrine can concede that some representations— such as words—do not involve resemblance, without thereby concluding that perceptual representations do not involve resemblance. Happily, Descartes’s second criticism does not end here. This is merely a rhetorical maneuver, designed to prepare his readers for the perhaps surprising suggestion that perceptual experiences are similar to words and do not rely upon resemblance to represent their objects. Here is how Descartes puts this suggestion: Now if words, which signify nothing except by human convention, suffice to make us think of things to which they bear no resemblance, then why could nature not also have established some sign which would make us have the sensation of light, even if the sign contained nothing in itself which is similar to this sensation? (CSM I 81) Here, Descartes suggests that perceptual experiences might function as natural signs that are akin to words in their not needing to resemble what they represent, but that differ from words in that they are the product of nature and not human convention. In itself, however, this is just a suggestion, one that might be surprising for Aristotelian Scholastics to hear, but one that does not yet provide any positive reason for them to abandon their commitment to a resemblance theory of perceptual representation.

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Descartes’s positive reason for thinking that perceptual representation does not involve resemblance is his account of the visual process. On his account, the inner stages of this process (stages six through eight) involve a fundamentally different form of motion than the external stages (stages one through five). Specifically, when light is received by the retina, it is converted from one form of motion to another. I will call this point of conversion the point of transduction. Because of this transduction, Descartes holds that perceptual representation simply cannot involve resemblance. Here is how Theo Meyering summarizes this aspect of Descartes’s view: Descartes concludes that scientific developments make the copy theory [i.e., the doctrine of species] untenable. That is to say, the physical impressions on the sensitive parts of the sensory organs (and finally the physiological patterns on the walls of the pineal gland) differ demonstrably both from their mechanical causes (the external objects and their various movements) and from the sensations which they in their turn generate. (Meyering 1989, 80) In sum: Descartes’s second criticism of the doctrine of species is that perceptual representations do not represent their objects in virtue of resembling them because the relevant resemblance that would be required for this to be the case is simply not present in the visual process. At this point, an important qualification is in order: the preceding gloss on Descartes’s second criticism would be misleading if it were taken to imply that there is no resemblance whatsoever between the inner effects and their external causes. This would be misleading not just because of the trivial point that everything resembles everything else in some respect or another. It would be misleading because on Descartes’s own account of the visual process there is one significant similarity between the inner effects and their external causes.26 Figure 3.2 makes this similarity evident. As this illustration shows, on Descartes’s account of the visual process, there is a similarity between the pattern of animal spirits flowing out of the pineal gland (on the left) and the causes of this pattern in the external world (on the right): specifically, the spatial relationship between the flow of animal spirits at points (a), (b), and (c) on the pineal gland mirrors the spatial relationship of the rotating particles at (A), (B), and (C) in the external world. In this sense, there is a resemblance between the inner effects and their external causes, in spite of the conversion of motion from one form to another in the center of the illustration (as well as the inverted spatial relationship of the points on the surface of the retina). Descartes’s account of the perceptual process does, in this sense, involve resemblance. Having conceded that there is a sense in which Descartes’s account involves resemblance, it is worth noting that this spatial similarity between the pattern of animal spirits on the pineal gland and its external cause does not imply a color similarity between the pattern and its external cause.

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Figure 3.2

Descartes’s Account of the Visual Process

Descartes gives no indication whatsoever that he thinks the pattern of animal spirits is multi-colored, that if (A) were red and (B) were blue, (a) would be red and (b) would be blue. The motion at (A) involves rotating particles, whereas the motion at (a) involves flowing animal spirits. Additionally, it is crucial to realize that even the spatial similarity between the internal pattern and its external cause is quite limited, in a way that this illustration unfortunately obscures by placing (A), (B), and (C) on the same vertical plane. If (A), (B), and (C) were on different vertical planes, that would not imply that (a), (b), and (c) would be different distances from the surface of the pineal gland. This brings out a crucial feature of Descartes’s account that is worth emphasizing: for Descartes, the transduction of light by the retina involves a form of resemblance that is strictly at the level of structural isomorphism, rather than (anything like) shared properties. Descartes himself makes this point by noting that even with regard to pictorial representation, strict resemblance in the sense of shared properties is often a detriment, rather than an asset. As he puts it, [I]n order . . . to represent an object better, [images such as engravings] must not resemble it. Now we must think in the same way about the images that are formed in our brain, and we must note that it is only a question of knowing how they can enable the mind to perceive all the

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diverse qualities of the objects to which they refer; not of [knowing] how the images themselves resemble their objects. (Descartes 2001, 90) Equally crucially, however, it is essential to note that even given the structural isomorphisms between the patterns of animal spirits on the pineal gland and their external causes (as well as the tendency that Descartes sometimes has to draw analogies between these patterns and pictorial representations), Descartes himself recognizes that there is a clear problem with thinking that these patterns are similar to pictures that we perceive. For, as he notes: [A]lthough this picture [i.e., the internal effect], in being so transmitted into our head, always retains some resemblance to the objects from which it proceeds, nevertheless, as I have already shown, we must not hold that it is by means of this resemblance that the picture causes us to perceive the objects, as if there were yet other eyes in our brain with which we could apprehend it. (Descartes 2001, 101)27 The problem with thinking that visual perceivers perceive the internal effects is that it opens up an endless regress. If, in order to perceive the external causes of visual experiences, perceivers must first perceive their internal effects, then, in order to perceive these internal effects, they presumably must perceive the internal effects of these internal effects. And, if in order to do that, they must perceive the internal effects of these internal effects of these internal effects, then an endless regress opens up.28 One final point needs to be made about the role of structural isomorphisms in Descartes’s account of the visual process. As C. R. Gallistell notes, Isomorphisms are formal correspondences between distinct systems of mathematical study. The best known such isomorphism is the one discovered by Descartes and Fermat between geometry and algebra: the isomorphism that is the foundation of analytical geometry and calculus. Descartes discovered a procedure—the use of Cartesian coordinates— that mapped the entities studied by geometers—points, lines, curves, and surfaces—into the entities of algebra—numbers, vectors (strings of numbers), and equations. (Gallistel 1990, 15) Given Descartes’s pioneering work with structural isomorphisms in mathematics, it is unsurprising that he might draw upon them as part of his explanation of the perceptual process.29 The most significant thing about the role that structural isomorphisms play in Descartes’s account, however, is that they underlie perhaps the most radical aspect of Descartes’s noresemblance theory of perceptual representation: the idea that the relationship between types of color experiences and types of motion is completely arbitrary. As Descartes puts this point,

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Descartes’s point is that, in itself, it does not matter whether TypeA or TypeB or TypeC color experience represents TypeX motion. All that matters is that there be a one-to-one causal relationship between types of color experience and types of motion; that is, for TypeA color experience to represent TypeX motion and TypeB color experience to represent TypeY motion, TypeX motion must cause TypeA color experience and TypeY motion must cause TypeB color experience.30 The key point is that for Descartes there is an arbitrary relationship between types of color experience and the types of motion that they represent. Summing up this qualification to Descartes’s second criticism of the doctrine of species: although it is true that on Descartes’s account of the visual process there is a sense in which the inner effects resemble their external causes, this resemblance is only an arbitrary structural isomorphism, according to which it is irrelevant which type of inner effect is caused by which type of external cause. For Descartes, the only thing that matters is that there be a one-to-one relationship between types of internal effects and types of external causes. With this qualification in place, I can now offer a summary account of Descartes’s criticism of the doctrine of species. Descartes’s criticism is that resemblance simply does not play the role accorded to it by Scholastic Aristotelians in their account of perceptual representation. It neither explains how perceivers are in perceptual contact with the objects of perception, nor explains how perceptual representations represent their objects of perception.

3.4

DESCARTES ON COLOR AS THE PROPER OBJECT OF VISION [R]egarding light and color . . . it is necessary to think that the nature of our mind is such that the force of the movements in the areas of the brain where the small fibers of the optic nerves originate cause it to perceive light; and the character of these movements cause it to have the perception of color: just as the movements of the nerves which respond to the ears cause it to hear sounds, and those of the nerves of the tongue cause it to taste flavors. —René Descartes, Optics (1637)31

According to the Aristotelian strand, sense modalities are functionally defined in terms of their abilities to take on different sorts of forms; vision is defined

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by color, just as hearing is defined by sound. This sort of definition is possible because Aristotle thinks there is a prior, and independent, difference between these different sorts of qualities. Descartes’s criticism of this aspect of the Aristotelian strand is that it gets things the wrong way around. In short, for Descartes, color is defined by vision; vision is not defined by color. According to Descartes, the difference between vision and hearing is based upon a difference in the sense organs themselves, in terms of how each of these organs responds to external stimuli. It is not based upon a prior, and independent, difference in the sorts of qualities perceived. This is because there is a sense in which what these sense organs are stimulated by is, at bottom, the same sort of thing: in both cases, it is matter in motion. Here is how Descartes puts this point: [The] sensation [of color] can be attributed only to the force of the blow which moves the small fibers of the optic nerve, as a strong light would do. And if this same force touched the ears, it could cause some sound to be heard; and if it touched the body in other parts, could cause it to feel some pain. (Descartes 2001, 102)32 Descartes’s point is that the place to locate the difference between the sensation of color and the sensation of sound is in the way in which the eye and the ear respond to the same sort of external stimuli (namely, matter in motion). It is these differences in the character of how the sense organs respond, rather than differences between different kinds of external stimuli, that define the differences between color and sound. In this respect, Descartes is the originator of a view that is often thought to have emerged much later, in the early nineteenth century.33 This view is the doctrine of specific nerve energies, which is often thought to have originated with Charles Bell in 1811 and to have been popularized by Johannes Peter Müller in 1835.34 As Arun Singh puts this doctrine, “In [a] nutshell, the doctrine of specific energies state[s] that every nerve produces its own characteristic quality of sensation and these qualities depend upon the structure and function of the nerve rather than upon characteristics of [the] stimulus” (Singh 1991, 66). Here is Müller’s own formulation of this idea, substituting electricity for matter in motion: [T]he same cause, such as electricity, can simultaneously affect all sensory organs, since they are all sensitive to it; and yet, every sensory nerve reacts to it differently; one nerve perceives it as light, another hears its sound . . . One nerve perceives a luminous picture through mechanical irritation, another one hears it as buzzing, another one senses it as pain. (Müller 1835, 752, in Clarke and O’Malley 1996, 205) Like Descartes, Müller identifies the differences between different sorts of perceptual experiences not in terms of fundamental differences in their

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external stimuli, but rather in terms of differences in how the sense organs themselves respond to these stimuli. In sum: Descartes and those who inherit his views on color, such as Robert Boyle, invert the Aristotelian conception of the relationship between vision and color. As Peter Anstley puts it, “In On the Soul Aristotle sought to demarcate the five senses by reference to their objects such as colours, sounds, etc. By contrast, [Descartes and] Boyle sought to explicate colours and sounds by reference to the senses” (Anstley 2000, 28). 3.5 THE CARTESIAN DISTINCTION BETWEEN PRIMARY AND SECONDARY QUALITIES We know size, shape and so forth in quite a different way from the way in which we know colours, pains and the like. This will be especially clear if we consider the wide gap between our knowledge of those features of bodies which we clearly perceive . . . and our knowledge of those features which must be referred to the senses . . . To the former class belong the size of the bodies we see, their shape, motion, position, duration, number and so on . . . To the latter class belong the colour in a body, as well as pain, smell, taste and so on. —René Descartes, Principles of Philosophy (1644)35

On the basis of his account of the visual process, Descartes introduces a distinction between two different sorts of objects of knowledge. I will call this distinction (following tradition) the distinction between primary and secondary qualities. My point in introducing this distinction is to bring out how it does not at all line up with the Aristotelian distinction between true and apparent colors. In order to make sense of Descartes’s motivations for introducing this distinction, it will help to introduce an imaginary case that is not a case of visual perception, but which is structurally identical to Descartes’s account of the visual process. I hope this imaginary case will allow us to think through some of the implications of Descartes’s account of the visual process without being distracted by the influence of the Aristotelian strand. Consider the following case: You have a type of cell phone that only accepts incoming calls and which arbitrarily assigns a one-to-one relationship between ring tones and incoming phone numbers. For instance, your phone has arbitrarily assigned the theme from Knight Rider to the phone number (415) 624-5975 and the theme from Sanford and Son to the phone number (217) 494-0492. Once your phone assigns a ring tone to a number, it consistently uses that same ring tone for that number (and only

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that number). Crucially, although each phone number gets its own ring tone, the phone never displays the actual phone numbers to you. Schematically, here is what is going on in this case: (415) 624-5975 → Knight Rider theme (217) 494-0492 → Sanford and Son theme In such a case, notice that there are two different sorts of knowledge that one could have about incoming phone calls. The first sort of knowledge is provided just by receiving calls: it is knowledge of what the various ring tones sound like. For instance, if (415) 624-5975 calls, one will hear the Knight Rider theme. One will thereby, just in virtue of having received that call, be in a position to know what this ring tone sounds like. The second sort of knowledge is not provided by simply receiving calls: it is knowledge of the various phone numbers. For instance, if (217) 494-0492 calls, one will hear the Sanford and Son theme, but one will not, just in virtue of having received that call, be in a position to know that (217) 494-0492 is calling. To have that sort of knowledge, you need something more. So far, this is just a distinction between knowledge that is made possible simply by receiving calls and knowledge that requires more than that. But now notice that there is a further difference between your knowledge of ring tones and your knowledge of phone numbers: ring tones, unlike phone numbers, are arbitrarily assigned by your particular cell phone. Your phone could just as easily have assigned the theme to All in the Family or the A Team to (415) 624-5975. This implies a further difference between your knowledge of ring tones and your knowledge of the phone numbers corresponding to those tones: in knowing that your phone is ringing with a particular tone, you thereby know what that tone sounds like—which is something that depends upon your particular cell phone—whereas if you know what phone number is calling you, you thereby know something that does not depend upon your particular cell phone. The distinction between your knowledge of ring tones and your knowledge of phone numbers is, in this sense, a distinction between cell phone-dependent and cell phoneindependent facts. That said, although your cell phone arbitrarily assigns ring tones to phone numbers, the same phone number will always produce the same ring tone (since there is always a one-to-one relationship between ring tones and phone numbers). For instance, in the case above, all and only calls from (415) 624-5975 will produce Knight Rider ring tones, and all and only calls from (217) 494-0492 will produce Sanford and Son ring tones. There are, thus, senses in which hearing ring tones does and does not give you knowledge of phone numbers. The sense in which it does not give you knowledge of phone numbers is that hearing the Knight Rider ring tone does not tell you that (415) 624-5975 is calling (no matter how many times that number

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calls you). The sense in which it does give you knowledge of phone numbers is that hearing the Knight Rider ring tone a second time allows you to know that it is the same number as before (even if you do not know what specific number that is). Alternately, first hearing Knight Rider and then hearing Sanford and Son allows you to know that the second call is from a different number. This situation makes it possible for us to say that hearing a ring tone allows us to perceive that a specific phone number is calling, even if we do not know what number it is. It also makes it possible for a distinctive sort of error to occur with regard to thinking about the ring tones, a sort that is not possible with regard to thinking about the phone numbers. In the case of ring tones, it is possible for us to make the mistake of thinking that the phone numbers themselves might resemble the ring tones that we hear. Imagine, for instance, how it would be a mistake to think that the harmonic relationship between the notes in the ring tone’s melody is an indication of the numerical relationship between the digits in the phone number. Descartes’s account of the visual process is structurally identical to the situation with this cell phone. Specifically, the cell phone case illustrates two of Descartes’s key ideas about the visual process: (i) there is a one-toone relationship between external physical causes and internal physiological effects, and (ii) the specific pairings of external physical causes and internal physiological effects is arbitrary. The combination of (i) and (ii) implies that color experiences both do and do not tell us something about their external physical causes. Realizing this makes it possible for us to make sense of some of Descartes’s most perplexing comments about color. Consider, for instance, the following comment: [W]hen we say that we perceive colors in objects, this is really just the same as saying that we perceive something in the objects whose nature we do not know. (CSM I 218) In this comment, Descartes is pointing out that according to his account of the visual process, the sameness or difference of inner psychological effects allows us to know that they are being produced by the same or different external causes. In neither case, however, does this allow us to know what these external causes are. When Descartes says that “We know size, shape and so forth in quite a different way from the way in which we know colours, pains and the like” (CSM I 217 [emphasis in original]) he is introducing a distinction between sensory-transduction-independent knowledge and sensory-transductiondependent knowledge, akin to the difference between knowing phone numbers and knowing ring tones. For example, on Descartes’s account of the visual process, our sensory knowledge of color essentially involves inner physiological effects of external physical causes, where there is an arbitrary relationship between these inner effects and their external causes,

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in virtue of the contingent way in which the retina just happens to transduce the motion of light.36 It is in this sense that our knowledge of color is sensory-transduction-dependent. By contrast, on the assumption that it is possible to know about the external physical causes of color experiences in a way that does not itself consist in knowing only the arbitrary assignment of inner physiological effects to these external causes, then there is a sensory-transduction-independent way of knowing about these causes. (Descartes himself thinks our knowledge of shape is an example of this other sort of knowledge. One need not agree with his choice of example in order to agree that there is this distinction between sensorytransduction-independent and sensory-transduction-dependent sorts of knowledge.) The objects of these two different sorts of knowledge are primary and secondary qualities. On this way of understanding the distinction, primary qualities are sensory-transduction-independent objects of knowledge and secondary qualities are sensory-transduction-dependent objects of knowledge.37 With the distinction between primary and secondary qualities in place, we can now bring out how it makes possible a distinctive sort of error. The error would be to think that our knowledge of secondary qualities is knowledge of primary qualities, or that sensory-transduction-dependent knowledge is the same as sensory-transduction-independent knowledge. Here is how Descartes introduces the possibility of this distinctive sort of error: [W]e easily fall into the error of judging that what is called colour in objects is something exactly like the colour of which we have sensory awareness; and we make the mistake of thinking that we clearly perceive what we do not perceive at all. (CSM I 218) The distinctive sort of error that Descartes is imagining here is that of conflating knowledge that essentially involves the arbitrary assignment of inner psychological effects with knowledge that does not involve the arbitrary assignment of inner psychological effects. It is precisely this sort of error that Descartes thinks the Aristotelian strand encourages.

3.6

THE CARTESIAN STRAND’S PRESENCE If, as Descartes would have it, light is simply a mechanical impulse or pressure transmitted instantaneously through contiguous particles of Air, then what about color? Either it comes to us by means of another kind of pressure transmitted through the aereal medium, or it is somehow ‘intended’ by light. Forced by logic to choose the latter alternative, Descartes explained color in terms of a spin imparted to the spherical particles of Air when the light-impulse

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The Cartesian Strand through them is interrupted by crass bodies, such as crystals. Variation in the rate of spin thus give rise to differences in color, red, for instance, being due to a faster spin than blue. It is impossible to overstate the importance of this idea, for, by reducing color to a mechanical by-product or ‘intention’ of light, Descartes took the first and most important step toward eliminating the long-standing distinction between light and color as intimately related but nonetheless independent entities. —A. Mark Smith, Descartes’ Theory of Light and Refraction (1987)38

At the core of the Cartesian strand of thought about color is a particular way of thinking about the relationship between color experiences, light, and vision. According to this way of thinking, although color experiences make us aware of colors (they are, after all, color experiences), they do not, in themselves, inform us about their external causes (which involve the transduction of light by the retina). There is, in this sense, something that color experiences make us aware of (how colors look) at the same time that there is something that they do not inform us of (their external causes). As a way of demonstrating how the Cartesian strand has come to play a role in how we think about color, consider the following two intuition pumps.

Intuition Pump #3 You are at Turnbull and Asser shopping for a tie with stripes that match the color of the windowpane pattern on your tweed jacket from Cordings. You find one with bold diagonal lines that you like. Looking at the tie alongside the jacket, the color of the lines looks the same as the color of the pattern, and everyone that you ask at the store agrees. You purchase the tie. When you return home, however, you use a microscope to compare the individual threads in your new tie with individual threads in your jacket and you discover that no individual threads in the tie match the individual threads that make up the windowpane pattern. The difference is that the color of the bold diagonal lines on the tie is the result of a simultaneous contrast effect, produced by the close juxtaposition of both lighter and darker threads, whereas the threads making up the windowpane pattern are uniform.39

Now ask yourself the following question: Q6: Was everyone at the tie store in the grips of a collective illusion when they said that the color of the diagonal lines was the same as the color of the window pane pattern? In response to Q6, I am inclined to deny that everyone at the store was the grips of collective illusion, because when it comes to the colors of things, seeing is knowing, in the sense that if two things look the same color

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(to normal perceivers in normal conditions), then they are the same color. That is, since everyone at the shop agrees that the color of the bold diagonal lines looks the same as the color of the windowpane pattern, they are the same color.

Intuition Pump #4 Impressed by your discovery about the threads in your tie, you start to examine the colors of other objects in your apartment. You are surprised to find out that when you look at a Cadbury Fruit & Nut chocolate bar through an empty toilet paper tube (which blocks your awareness of the surrounding colors and the background illumination conditions), it looks orange, not brown. A quick survey of other things in your apartment reveals that everything that normally looks brown looks either orange or yellow when viewed through the empty toilet paper tube.40

Now ask yourself the following question: Q7: Have you just discovered that nothing is ever brown? In response to Q7, I am inclined to say that I have not just discovered that nothing is ever brown. Rather, I have just discovered that looking brown—which is the same as being brown (when things look brown to normal perceivers in normal conditions)—requires seeing objects in context, not through empty toilet paper rolls. If you share these inclinations, then that attests to the presence of the Cartesian strand in how we both think about the relationship between color experiences, light, and vision. It implies that we both think there is a sense in which looking the same color suffices for being the same color. It implies, in other words, that we both reject some of the underlying theoretical commitments of the Aristotelian strand, such as the idea that a rainbow’s looking red does not suffice for it being red. Moreover, it implies that we would probably both reject the following Aristotelian characterization of what it is for something to be blue: [For Aristotle] [t]o be blue, for example, is not to look a certain way, but to have a certain essence and definition. We should not be misled by the fact that we are talking here about sensible qualities into confusing perceptible character with essence and definition. The essence of a sensible quality [for Aristotle] is that by which it is what it is, and its definition is that by which we understand what it is; and neither the essence nor the definition is identical with the perceptible character of that quality, though it is true that without that essence it would not look (or sound, taste, feel, etc.) the way it does to us. (Simmons 1994, 118) According to the Aristotelian strand, there is a difference in kind between the blueness of a pair of blue jeans and the blueness of a rainbow.41 According

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to the Cartesian strand, by contrast, these are both equally well instances of blueness.

Evidence For evidence that the Cartesian strand has become an intuitive way of thinking about color, such that it plays a role in contemporary philosophical debates about color, consider the following comments from P. F. Strawson, David Hilbert, and John Hyman: Colors are visibilia, or they are nothing. (Strawson 1979, 56) Colors that cannot be seen . . . are not plausibly colors at all. (Hilbert 1992, 359) Our basic conception of colors is rooted in one fundamental principle, namely, that an object’s color is part of its appearance, in other words, that it is part of how it looks. (Hyman 2006, 15) Running throughout these comments is a shared idea: looking a certain way is an essential part of what it is to be a certain color. For further evidence of the Cartesian strand’s presence in contemporary philosophical debates, as well as evidence of how there can be intra-personal variation in how one and the same contemporary philosopher thinks about colors, consider the following quotation from Mark Johnston’s “How to Speak of the Colors” (the same article that was quoted as evidence of the continuing presence of the Aristotelian strand in the last chapter): I take myself as having come to understand the complete nature of the property of being nauseated one afternoon twenty five years ago when I tasted a juicy apricot on a ferry crossing from Melbourne to Hobart [in rough seas]. Similarly, if I conceive of the magenta of the sunset as a (constituted) disposition to produce a certain visual experience in subjects like me, and I now discover myself to be responding just so, I can be in possession of all there is to know about the essential nature of the dispositional property that is magenta. I do not thereby know the contingent details of how magenta might be physically realized here before my eyes or anywhere else. But that is ignorance of the relation between the disposition and the other properties which happen to realize the disposition. I do seem to know everything intrinsic and essential to the response-disposition that is magenta. (Johnston 1992, 258) In this quotation, we can see the Cartesian idea that there is something that color experiences make us aware of (how colors look) at the same time that there is something that they do not inform us of (their external causes). This is vivid evidence of the Cartesian strand’s presence in contemporary philosophical debates about color.

The Cartesian Strand 3.7

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INTERLUDE: WHERE WE FIND OURSELVES NOW

Think back to the four intuition pumps that have now been introduced. The first and second asked whether we find it intuitive to think that colors exist independently of light and perceivers. The third and fourth asked whether we find it intuitive to think that there is a sense in which looking the same color suffices for being the same color. If you are like me, and find either (or both) the first and second intuition pumps compelling at the same time that you find either (or both) the third and fourth intuition pumps compelling, then we find ourselves in a peculiar sort of situation. It is a situation in which we find aspects of two distinct strands of thought about color to be intuitive, even though one of these strands (the Cartesian) only first emerges in opposition to the other (the Aristotelian). In such a situation, our thought about color is unified only in the historically contingent sense that these conflicting strands of thought, “have been tied together into such a tight unity that they seem inseparable and are no longer visible as strands” (Clark 1998, 854). This is a peculiar sort of unity. These strands seem inseparable only because of their historical juxtaposition and interaction, not because of any intuitive or logical connection between them. This peculiar sort of unity brings with it the possibility of a peculiar sort of problem. The problem is that these two strands of thought introduce two different reality/appearance distinctions that cut across each other: the Aristotelian distinction between true and apparent colors, and the Cartesian distinction between primary and secondary qualities. These are two conflicting ways of thinking about whether something really is colored. To see why this peculiar situation is problematic, it will help to introduce some technical terminology for referring to the two conflicting reality/appearance distinctions introduced by the Aristotelian and Cartesian strands: The Aristotelian distinction (between true and apparent colors): real1 vs. apparent1 The Cartesian distinction (between primary and secondary qualities): real2 vs. apparent2 Now consider the situation of someone, like myself, who finds both the Aristotelian and the Cartesian strands to be intuitive. The problem is that if my thought about color exhibits this sort of historically contingent unity (which does not presuppose logical consistency), it is all too easy for me to assume that for colors to be real, they must be both real1 and real2 simultaneously. If I make this assumption, however, then the apparently innocent philosophical question “Are colors real?” turns out not to be innocent at all. In such a situation, this very question presupposes that colors simply

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cannot be real, because it is impossible for colors to be both real1 and real2 simultaneously. Consider, for example, the blueness of a pair of blue jeans. This blueness is real1 in the sense of not being apparent1, but this does not imply that it is real2 in the sense of not being apparent2. All real1 colors are apparent2. A further problem is that if I fail to recognize the historically contingent nature of my conflation of these two senses of “real,” I am likely to be dissatisfied with either a positive or a negative answer to the question “Are colors real?” On the one hand, since colors cannot be both real1 and real2, I am unlikely to be content with thinking that colors are simply “real.” On the other hand, since there are plenty of examples of colors—like the blueness of blue jeans—that are not merely apparent1 in the manner of visual illusions, I am likely to be dissatisfied with thinking that colors are simply “merely apparent.” The fundamental problem is that insofar as the question “Are colors real?” presupposes the conflation of real1 and real2, I am unlikely to find any answers to this question satisfying.

NOTES 1. Descartes (CSM I 218). 2. By referring to this as a “discovery,” I do not mean to imply that everything about the Cartesian strand is true, or that everything about the Aristotelian strand is false. The full story is much more complicated. Although it is worth noting that many of “the details of Descartes’ explanatory account are widely erroneous when viewed from the perspective of modern scientific theory” (Cottingham 1990, 232), it is equally worth noting that many of the bigger picture aspects of Descartes’s account of light and vision are not widely erroneous, and do suffice to raise substantive problems for the Aristotelian strand. Accordingly, this chapter begins the process of assessing what is, and is not, true in each of these strands by disentangling three specific Cartesian criticisms of three specific aspects of the Aristotelian strand. 3. Boyle (1664, 84). 4. For discussions of Descartes’s views on light and vision that pay special attention to the scientific background to these views, see Sabra (1967, 17–135), Van Hoorn (1972, 150–206), Maull (1978), Smith (1987), Meyering (1989, 7–108), MacKenzie (1990), Shea (1991, 227–249), Wolf-Devine (1993), Ribe (1997), Gaukroger (2001, 135–160 and 180–221), Atherton (2004), Buchwald (2008), Osler (2008), and Schuster (2013). 5. For simplicity’s sake, I here treat a tendency to motion as a kind of motion. Descartes himself switches between referring to light as a kind of motion and a tendency to motion and at (CSM III 73–4) claims that motion and tendencies to motion obey the same laws. 6. One caveat is worth mentioning. Descartes, like Aristotle, thinks that the illumination of a transparent medium is instantaneous. That does not, however, stop Descartes from thinking that light is a type of motion, because he thinks that the propagation or transmission of the motion of light happens in an instant. His first two models for understanding light are explicitly intended to bring out how light can be a type of motion that is instantaneously transferred through a medium. As he puts it, with regard to his first model, it “will prevent you from finding it strange at first that [the light of the sun] can extend its rays

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7. 8.

9. 10. 11.

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in an instant from the sun to us; for you know that the action with which we move one of the ends of a stick must thus be transmitted in an instant to the other end” (Descartes 2001, 67). For overviews of Kepler’s work in optics, see Lindberg (1976, 185–208), Straker (1976), Crombie (1991), Smith (2004), Mancosu (2006), Gal and Chen-Morris (2010), Darrigol (2012, 26–36), and Smith (2015). Kepler himself drew upon the work of Felix Platter, who was the first (in 1583) to clearly state that the retina is the part of the eye that plays the receptive role in vision. Previous theorists held that it is the exterior surface of the eye that plays the receptive role. For discussion, see Howard (1996, 32). Although it will not be emphasized here, the discovery of the inverted retinal image is tremendously philosophically significant in its own right. As A. Mark Smith puts it, “At bottom, therefore, Kepler’s account of retinal imaging represented not a continuation, but a repudiation of the medieval optical tradition. At issue was the relationship between objective cause, in the form of light and color, and subjective effect, in the form of perceptual impressions. Medieval optics was explicitly designed to bind the two as tightly as possible by means of intentional representations. Keplerian optics was implicitly designed to sever this bond by interposing the opaque wall of the retina between the perceiving subject and the perceived object. Out of the resulting disjunction arose not only the modern science of physical optics but also the mind-body dualism of Descartes and his philosophical successors” (Smith 2004, 194). The problem for Aristotelian Scholastic accounts is not just that the retinal image is inverted, however. A further problem is that this image only has the form it has in virtue of the focusing role of the crystalline humor in the front of the eye. For discussion of this additional problem for the Aristotelian Scholastic view, see Meyering (1989, Chap. 4). For a survey of our current understanding of the physiology of color vision, see Palmer (1999, Chap. 3). Boyle (1664, 31). For discussion of Descartes’s theory of the rainbow, see Minnaert (1954, 174–176), Westfall (1962, 339–334), Sabra (1981, 60–68), Boyer (1987, 200–219), Tiemersma (1988), Shea (1991, 202–225), Armogathe (2000), Lee and Fraser (2001, 181–193), Werrett (2001), Gaukroger (2006, 382–389), and Buchwald (2008). Descartes’s theory of the rainbow was not completely unprecedented. In the fourteenth century, both Theodoric of Freiburg (1250–1310) and Kamāl al-Dīn al-Fārisī (1267–1319) proposed similar theories, according to which the primary rainbow results from two refractions and one reflection, and the secondary rainbow results from two refractions and two reflections (for a clear summary of Theodoric’s work, see Wallace [1959]; for al-Fārisī’s, see Topdemir [2007]). It is only in retrospect, however, that their accounts have come to be widely known. They did not know of each other’s work, and their work was mostly likely unknown to Descartes and his contemporaries. Moreover, unlike either Theodoric or al-Fārisī, Descartes was able to give a completely mathematical account of the reflections and refractions involved in producing rainbows. He was able to do this because he was familiar with both laws involved, the laws of reflection and refraction. On the one hand, given that the law of reflection was known since antiquity, this law was available to both Theodoric and al-Fārisī. On the other hand, the law of refraction was first published by Descartes only in 1637, alongside his theory of the rainbow, so this law was unavailable to either of them. (Descartes was not the first to discover the law of refraction, though he was the first to publish its discovery. Both Thomas Harriot and Willebrord Snellius independently discovered the law of refraction before him (for a summary of Harriot’s work,

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12.

13.

14. 15.

16.

The Cartesian Strand see [Kwan et al. 2002]; for Snellius [or Snell or Snel], see Hentschel [2001]). Neither used the law of refraction to explain rainbows, however, and Descartes probably discovered it independently (for discussion see Scott [1976, 38–39], Shea [1991, 149–150], and Gaukroger [1995, 141]). Taken as a whole, Descartes appears to have arrived at his theory of the rainbow on his own. As Carl Boyer puts it in his history of theories of rainbows, “Descartes did not simply rediscover the fourteenth-century theory, as many histories hold; he gave it true scientific status by showing the quantitative agreement of theoretical calculations with the results of observations” (Boyer 1987, 211). The question of who should get credit for this theory, however, is irrelevant for our purposes. What is significant about Descartes’s theory is that it successfully uses mathematical laws to explain many of the most salient observable aspects of rainbows. The primary rainbow is the rainbow we normally see, at 42° in the sky, made up of bands of red, orange, yellow, green, blue, indigo, and violet (viewed from top to bottom). The secondary rainbow is the rainbow we sometimes see in addition to the primary rainbow, when one sees a double rainbow. It is 10° above the primary rainbow, at 52° in the sky, one tenth as bright as the primary rainbow, twice as wide, and the order of its colors is inverted. For a clear summary of the similarities and differences of primary and secondary rainbows, see Schaaf (1983). I know of no better visual introduction to the distinction between primary and secondary rainbows than the “Yosemitebear Mountain Double Rainbow 1–8–10” video: http://www.youtube.com/ watch?v=OQSNhk5ICTI (accessed online November 15, 2013). For Descartes’s comments on his theory of the rainbow as a way of understanding his method, see the quotation at the beginning of this section as well as his letter to P. Vatier on 22 February 1638 in which he claims that “I have given a glimpse (of the method [outlined in the Discourse on Method]) in describing the rainbow.” (CSM III 85). As Jed Buchwald notes, “the only account that Descartes ever developed which invokes his model [of the invisible world] in relation to both quantitative implications and to experiments is the one that he provided for the rainbow.” (Buchwald 2008, 1) For discussion of Descartes’s theory of the rainbow as a model for his method for arriving at knowledge, see Smith (1987), Garber (1988 and 1992), Hatfield (1988), and Tiermersma (1988). For an illuminating discussion of the history of these fountains and their impact on Descartes’s thought, see Werrett (2001). Descartes himself only describes this glass sphere as a “perfectly round and transparent large flask” (Descartes 2001, 332) but Armogathe (2000, 252) and Gaukroger (2006, 382) speculate that it might have been a chamber pot, given that that was what earlier experimenters (such as Libert Froidmont) used. Witelo also used a water filled glass, but, unlike Descartes, he explicitly denied its relevance to “natural” rainbows, on the grounds that its colors were produced “artificially.” See Lee and Fraser (2001, 161). Descartes’s theory holds on to one key element of earlier theories, the idea that the colors of the rainbow are produced by the modification of light, in the sense that the raindrops change the color of the light passing through them. It is not until Newton’s pioneering work that this idea is finally abandoned, in favor of the idea that the colors of the rainbow are produced by the separation of light, in the sense that the raindrops filter out the distinct colors that are already present in the light. The distinction between modification and separation theories is important, as Westfall (1962), Shapiro (1980 and 1994), Nakajima (1984), and Zemplén (2005) all emphasize. That said, this distinction is orthogonal to the focus of this chapter, which is on Descartes’s reasons for rejecting aspects of the Aristotelian strand.

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17. Jed Buchwald provides the following useful model of the sort of motion involved in Descartes’s account, in terms of the motion of billiard balls: “If the billiard ball has not been hit too hard, then it will roll on the table without slipping, which establishes a direct link between its rotational speed about the point of contact with the table and its translational speed. If, per contra, the ball is hit hard, the connection between rolling and translating will be broken, and it will slip along the surface while spinning. Anyone who has spent a moment watching or, even better, playing billiards has seen or experienced the effect. White light then corresponds to the state of the beam when the (tendency to) rotation of the spheres is coupled to their (tendency to) translation; colours arise when the two are decoupled” (Buchwald 2008, 19). 18. Moreover, as noted above, Descartes himself gives multiple different models for how he understands the motion of light. Even Descartes’s general claim that “light [is] a certain movement or action” (Descartes 2001, 67) stands in need of qualification. For, as Gaukroger notes, “It is the pressure, not the motion of the balls that does the work, and ‘the force of light does not consist in any duration of motion, but only in the pressing or first preparation of motion, even though actual motion may not result from this pressure’ (Art. 63). Light is, in short, a pressure caused by a tendency to centrifugal motion” (Gaukroger 2002, 149–50). 19. An entire book could be written about this sentence. In what follows, I explain one reason Descartes has for thinking that his account of rainbow colors generalizes to all colors. But I do not explore why he took it to be “obvious” that his account generalizes, or how generalizing in this manner simultaneously has the benefit of opening up new lines of inquiry at the same time that it has the cost of (seeming) to close down others (at least temporarily). 20. For discussion of Kepler’s rejection of this distinction, see Lee and Fraser (2001, 179); for Beeckman, see Crone (1999, 58); for Gassendi, see Guerlac (1986, 16); for Grimaldi, see Westfall (1962, 344); for De La Chambre, see Crone (1999, 74); for Boyle, see Shapiro (1984, 4); for Charleton, see Guerlac (1986, 17). 21. Descartes (CSM I 295). 22. Here is how Descartes makes this point, with regard to the first part of the doctrine of species, on the supposed need to posit colors and other “substantial forms” and “real accidents” to explain the causal process of sense perception: “But the principal argument which induced philosophers to posit real accidents was that they thought that sense-perception could not be explained without them, and this is why I promised to give a very detailed account of sense-perception in my writings on physics, taking each sense in turn” (CSM II 293). 23. For Descartes, that the retina’s absorption of light produces the same rotating motion in the eye is evident from the literal blueness of the retinal image (in the case of seeing of a pair of blue jeans). Descartes notes this at (Descartes 2001, 94). In this sense, Descartes takes Aristotle’s wax seal analogy (DA II.12, 424a18–21) even more literally than Aristotle himself (pace Literalist readings of Aristotle’s account of sense perception). As Descartes puts it, “Sense perception occurs in the same way in which wax takes on an impression from a seal. It should not be thought that I have a mere analogy in mind here: we must think of the external shape [or motion] of the sentient body as being really changed by the object in exactly the same way as the shape [or motion] of the surface of the wax is altered by the seal” (Descartes CSM I40). 24. Alternately, Descartes claims that “It is necessary, to take care, not to suppose that the mind, to perceive needs to regard some images which are sent by the objects to the brain, which generally is what the philosophers will make us

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25. 26.

27.

28.

29. 30. 31. 32.

The Cartesian Strand believe.” “It is necessary to beware of assuming that in order to sense, the mind needs to perceive certain images transmitted by the objects to the brain, as our philosophers commonly suppose” (Descartes 2001, 89). For useful discussion of Descartes’s no-resemblance theory of perceptual representation, see Van Hoorn (1972, Chap. 5); Meyering (1989, Chap. 6); Simmons (1994, Chaps. 3 and 4). This similarity is explored in Watson (1995, 19–48), in the context of arguing for the provocative claim that all accounts of perceptual representation must involve similarities at some level or another (in a non-trivial sense). The presence of this similarly has, I think, misled some readers of Descartes to overlook the differences between Descartes’s no-resemblance account of perceptual representation and the resemblance accounts of his Scholastic Aristotelian opponents (e.g., Hwang 2011). Here is how Ned Block puts this same point 344 years later: “Brain scientists have found no pictures in the brain and even if they had, the presence of pictures wouldn’t explain the phenomena unless the brain also contained an internal eye to view them and an internal flashlight and internal hands to manipulate them, etc. (And even if we postulate an internal eye, would there be still another eye in that eye’s brain?)” (Block 1981, 2). I am here bracketing the enormous interpretative debate about whether Descartes thinks that perceivers perceive inner representations in some other sense. On a traditional, representationalist reading of Descartes, perceivers directly or immediately perceive inner representations and only indirectly perceive the external world. Advocates of this representationalist reading include Reid (1764/1970), Kemp Smith (1902), Hamelin (1921), Ryle (1949), Bennett (1965), Kenny (1968), Rorty (1979), Reed (1982), Wells (1984), Bolton (1986), Mackenzie (1989), Cottingham (1990), Watson (1995), Nelson (1996), Wilson (1999a and 1999b), Simmons (2003), Atherton (2004), and Smith (2005). On a more recent, anti-representationalist reading of Descartes, the only sense in which Descartes thinks that there are inner representations is in the sense of acts of perception themselves. On this reading, Descartes thinks that in these acts, when they are veridical, we directly perceive the external world. This anti-representationist reading is mostly based on criticisms of the traditional reading, such as criticism that rests upon the conflation of a causal intermediary with a perceptual intermediary. As Ronald Arbini puts this criticism: “For Descartes, the role of the back-of-eye image in the process of perception is a theoretical one and not one providing an object of observation. Whatever else is wrong with [the representationalist reading], it should be clear that [it] systematically confuse[s] the roles of observable and theoretical entities in geometrical theories like those of Descartes and Kepler” (Arbini 1983, 327). Simply put, the fact that Descartes thinks that there are inner causal intermediaries that play a role in bringing about conscious visual experiences of the colors of things does not imply that he thinks that we consciously perceive any of these causal intermediaries. Advocates of this antirepresentationalist reading include Turbayne (1963), Arbini (1983), Yolton (1984), Cook (1987 and 1996), Keating (1999 and 2001), Brown (2007), Pessin (2009), and Hwang (2011). This connection is explored in Haugeland (1989, Chap. 1). This is a necessary but not sufficient condition because Descartes does not think that causation suffices for representation. This topic is discussed at length in the next two chapters. Descartes (2001, 101). This quotation is yet another example of how there are two sides to many of Descartes’s programmatic statements. On the one hand, this statement has the

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33.

34.

35. 36.

37.

38. 39.

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benefit of making it conceivable that light and sound might have a shared form (e.g., that they might both be waves), something which is inconceivable on the Aristotelian account. On the other hand, this statement has the cost of overlooking the fact that if you shine a light on someone’s eardrum, he or she does not hear anything. For a useful discussion of the history of analogies and disanalogies between light and sound, see Darrigol (2010a and 2010b). Others who credit Descartes with originating this view include (Crombie 1990) and (Hatfield 2009). As Gary Hatfield puts it: “Descartes is responsible for an early statement of a principle that is similar to Johannes Müller’s law of specific nerve energies. Descartes held that the various sensory nerves operate according to similar mechanical principles: by the motion of nerve threads, which cause an opening of the nerve tubules, causing a flow of animal spirits, causing a sensation in the mind. . . . The character of the sensation depends upon which nerve is affected: optical, auditory, olfactory, and so on, each of which terminates in a specific region of the brain. In this way, Descartes introduced the conceptual framework according to which the characteristics of changes in a brain state are directly correlated with characteristics of the resulting sensations” (Hatfield 2009, 13). For a useful overview on Bell’s and Müller’s work, see Boring (1929). Boring notes that, “there is in this doctrine not one single principle that was new with Müller.” However, “Müller gave the theory explicit and precise formulation” and “though he may have originated nothing in it, he placed the seal of orthodoxy upon it” (1929, 81). Descartes (CSM I 218 [emphasis in original]). As a way of making the arbitrariness of this relationship intuitive, it helps to think of the transduction involved in literal terms, in terms of the conversion of one sort of motion into another sort of motion. Think, for instance, of the way in which different sorts of shock absorbers convert the vertical motion of a car in different ways. I do not wish to give the impression that this is the only way in which one might formulate a distinction between primary and secondary qualities, or even that this is the only way in which Descartes himself suggests that we might formulate such a distinction. (Descartes himself does not use the terminology of “primary” and “secondary” qualities, but one need not use that specific terminology to draw such a distinction.) My formulation of Descartes’s distinction between primary and secondary qualities is merely intended to bring out one aspect of his thought as clearly as possible. I am bracketing the considerable amount of debate that surrounds the larger question of how, exactly, this distinction should be drawn, or even whether it represents a tenable distinction (or set of distinctions) at all. For the purposes of this chapter, the only thing that matters about Descartes’s invocation of something like (what has come to be called) a primary/secondary quality distinction is that such a distinction offers us quite a different way of understanding the appearance/reality distinction as it relates to colors than that offered by the Aristotelian distinction between true and apparent colors. My point is that regardless of how one formulates a distinction between primary and secondary qualities, this distinction does not line up with the Aristotelian distinction between true and apparent colors. For a useful overview of some of the different formulations of the primary/secondary quality distinction in the seventeenth century, see MacIntosh (1976). For a useful collection of articles on the history of the primary/secondary quality distinction, see Nolan (2011). Smith (1987, 78–80). Simultaneous contrast is “a change in [the] apparent lightness, hue, and/ or chroma of a colored field caused by an adjacent or surrounding field of

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different lightness, hue, and/or chroma” (Kuehni 2005, 185–6). For a clear overview of color contrast effects, see Arnkil (2013, 92–114). For the history of studies of color contrast, see Wade (1999, 144–146). 40. Brown is a contrast color. As Jonathan Cohen explains, “Contrast colors are colors whose appearance depends essentially on contrast effects—[they are] colors that cannot appear in the absence of contrast. Contrast colors include many we encounter everyday (outside the psychophysics laboratory), such as brown, olive, pure white, and pure black. That these colors disappear when contrast is eliminated is a striking fact: subjects are often surprised that brown objects, when viewed through a reduction tube, appear either orange or yellow” (Cohen 2009, 23). 41. It is worth noting that when Aristotle talks about contrast colors, he seems to treat them as illusions. See (Meteor. III.4, 374b7–375a29).

WORKS CITED Anstley, P. R. The Philosophy of Robert Boyle. London: Routledge, 2000. Arbini, Ronald. “Did Descartes Have a Philosophical Theory of Sense Perception?” Journal of the History of Philosophy 21 (1983): 317–337. Aristotle. The Complete Works of Aristotle. Edited by J. Barnes. Princeton: Princeton University Press, 1984. Armogathe, Jean-Robert. “The Rainbow: A Privileged Epistemological Model.” In Descartes’ Natural Philosophy, edited by Stephen Gaukroger, John Schuster, and John Sutton, 249–57. London: Routledge, 2000. Arnkil, Harald. Colours in the Visual World. Helsinki: Aalto ARTS Books, 2013. Atherton, Margaret. “ ‘Green Is Like Bread’: The Nature of Descartes’ Account of Color Perception.” In Perception and Reality: From Descartes to the Present, edited by Ralph Schumacher, 27–42. Paderborn: Mentis, 2004. Bennett, Jonathan. “Substance, Reality, and Primary Qualities.” American Philosophical Quarterly 2 (January, 1965): 1–17. Block, Ned J. “Introduction.” In Imagery, 1–18. Cambridge, MA: MIT Press, 1981. Bolton, Martha. “Confused and Obscure Ideas of Sense.” In Essays on Aristotle’s Ethics, edited by Amélie O. Rorty, 389–403. Berkeley: University of California Press, 1986. Boring, Ewald. A History of Experimental Psychology. New York: AppletonCentury-Crofts, 1929. Boyer, Carl. The Rainbow: From Myth to Mathematics. 2nd ed. Princeton: Princeton University Press, 1987. Boyle, Robert. Experiments and Considerations Touching Colours. London: Henry Herringman, 1664. Brown, Deborah. “Objective Being in Descartes: That Which We Know or That By Which We Know.” In Representation and Objects of Thought in Medieval Philosophy, edited by Henrik Lagerlund, 135–153. Hampshire, England: Ashgate Publishing, 2007. Buchwald, Jed Z. “Descartes’s Experimental Journey Past the Prism and Through the Invisible World to the Rainbow.” Annals of Science 65, no. 1 (2008): 1–46. Clark, Maudemarie. “Friedrich Nietzsche.” In Routledge Encyclopedia of Philosophy, edited by Edward Craig, 844–861. London: Routledge, 1998. Clarke, Edwin and C.D. O’Malley. The Human Brain and Spinal Cord: A Historical Study Illustrated by Writings from Antiquity to the Twentieth Century. Second Edition. San Francisco: Norman Publishing, 1996.

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Cohen, Jonathan. The Red and the Real: An Essay on Color Ontology. Oxford: Oxford University Press, 2009. Cook, Monte. “Descartes’ Alleged Representationalism.” History of Philosophy Quarterly 4 (1987): 179–193. ———. “Descartes and the Dustbin of the Mind.” History of Philosophy Quarterly 13, no. 1 (1996): 17–33. Cottingham, John. “Descartes on Color.” Proceedings of the Aristotelian Society New Series 90 (1990): 231–246. Crombie, A. C. “Kepler: De Modo Visionis. A translation from the Latin of Ad Vitellionem Paralipomena, V, 2, and related passages on the formation of the retinal image.” In L'Aventure de la Science, Mélanges Alexandre Koyré, 135–72, Paris: Hermann, 1964. ———. Science, Optics and Music in Medieval and Early Modern Thought. London: Hambledon & London, 1990. ———. “Expectation, Modelling and Assent in the History of Optics. II. Kepler and Descartes.” Studies in History and Philosophy of Science 22, no. 1 (1991): 89–115. Crone, Robert. A History of Color: The Evolution of Theories of Light and Color. Dordrecht: Kluwer, 1999. Darrigol, Oliver. “The Analogy Between Light and Sound in the History of Optics from the Ancient Greeks to Isaac Newton. Part 1.” Centaurus 52, no. 2 (2010a): 117–155. ———. “The Analogy Between Light and Sound in the History of Optics from the Ancient Greeks to Isaac Newton. Part 2.” Centaurus 52, no. 3 (2010b): 206–257. ———. A History of Optics from Greek Antiquity to the Nineteenth Century. Oxford: Oxford University Press, 2012. Descartes, René. Oeuvres de Descartes. 11 vols. Edited by Charles Adam and Paul Tannery. Paris: J. Vrin, 1983. [Abbreviated as AT.] ———. The Philosophical Writings of Descartes. 3 vols. Translated by John Cottingham, Robert Stoothoff, and Dugald Murdoch. Volume 3 including Anthony Kenny. Cambridge: Cambridge University Press, 1988. [Abbreviated as CSM.] ———. Discourse on Method, Optics, Geometry, and Meteorology. Translated by Paul J. Olscamp. Indianapolis: Hackett, 2001. Gal, Olfer and Raz Chen-Morris. “Baroque Optics and the Disappearance of the Observer: From Kepler’s Optics to Descartes’ Doubt.” Journal of the History of Ideas 71, no 2 (2010): 191–217. Gallistel, Charles. The Organization of Learning. Cambridge, MA: Bradford Books, 1990. Garber, Daniel. “Descartes and Method in 1637.” In PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association. Philosophy of Science Association (January, 1988): 225–236. ———. Descartes’ Metaphysical Physics. Chicago: University of Chicago Press, 1992. Gaukroger, Stephen. Descartes: An Intellectual Biography. Oxford: Oxford University Press, 1995. ———. “Descartes on Seeing: Epistemology and Visual Perception.” Philosophical Books 37, no. 1 (1996): 36–38. ———. Francis Bacon and the Transformation of Early-Modern Philosophy. Cambridge University Press, 2001. ———. Descartes’ System of Natural Philosophy. Cambridge: Cambridge University Press, 2002. ———. The Emergence of a Scientific Culture: Science and the Shaping of Modernity, 1210–1685. Oxford: Oxford University Press, 2006.

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Guerlac, Henry. “Can There Be Colors in the Dark? Physical Color Theory Before Newton.” Journal of the History of Ideas 47, no. 1 (1986): 3–20. Hamelin, Octave. Le système de Descartes. Paris: Librarie Felix Alcan, 1921. Hatfield, Gary. “Science, Certainty, and Descartes.” In PSA: Proceedings of the Biennial meeting of the Philosophy of Science Association (January 1988): 249–262. ———. “Rationalist Roots of Modern Psychology.” In Routledge Companion to Philosophy of Psychology, edited by John Symons and Paco Calvo, 3–21. London: Routledge, 2009. Haugeland, John. Artificial Intelligence: The Very Idea. Cambridge: MIT Press, 1989. Hentschel, Klaus. “Das Brechungsgesetz in der Fassung von Snellius.” Archive for History of Exact Sciences 55 (2001): 297–344. Hilbert, David. “What Is Color Vision?” Philosophical Studies 68 (1992): 351–370. Howard, Ian P. “Alhazen’s Neglected Discoveries of Visual Phenomena.” Perception 25 (1996): 1203–1218. Hwang, Joseph W. “Descartes and the Aristotelian Framework of Sensory Perception.” Midwest Studies in Philosophy 35 (2011): 111–148. Hyman, John. The Objective Eye: Color, Form, and Reality in the Theory of Art. Chicago: University of Chicago Press, 2006. Johnston, Mark. “How to Speak of the Colors.” Philosophical Studies 68 (1992): 221–263. Keating, Laura. “Mechanism and the Representational Nature of Sensation in Descartes.” Canadian Journal of Philosophy 29, no. 3 (1999): 411–429. ———. “The Role of the Concept of Sense in Principles IV, 189–98.” British Journal for the History of Philosophy 12, no. 2 (2001): 199–222. Kenny, Anthony. Descartes: A Study of his Philosophy. New York: Random House, 1968. Kepler, J. Ad Vitellionem paralipomena. Frankfurt: C. Marnius & Heirs of J. Aubrius, 1604. Portions of this are translated in Crombie (1964). Kuehni, Rolf. Color: An Introduction to Practice and Principles. 2nd ed. Hoboken, NJ: John Wiley & Sons, 2005. Kwan, Alistair, John Dudley, and Eric Lantz. “Who Really Discovered Snell’s Law?” Physics World 15, no. 4 (2002): 64. Lee, Raymond and Alistair Fraser. The Rainbow Bridge: Rainbows in Art, Myth, and Science. University Park: Penn State Press, 2001. Lindberg, David. Theories of Vision from al-Kindi to Kepler. Chicago: University of Chicago Press, 1976. Macintosh, John J. “Primary and Secondary Qualities.” Studia Leibnitiana 8, no. 1 (1976): 88–104. MacKenzie, Ann Wilbur. “Descartes on Life and Sense.” Canadian Journal of Philosophy 19, no. 2 (June 1989): 163–192. ———. “Descartes on Sensory Representation: A Study of the Dioptrics.” Canadian Journal of Philosophy, Supplementary Volume 19 (1990): 109–147. Mancosu, Paolo. “Acoustics and Optics in the Early Modern Period.” In The Cambridge History of Science, vol. 3: Early Modern Science, edited by Lorraine Daston and Katharine Park, 596–631. Cambridge: Cambridge University Press, 2006. Maull, Nancy. “Perception and Primary Qualities.” PSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association 1 (1978): 3–17. Meyering, Theo. Historical Roots of Cognitive Science. Boston: Kluwer, 1989. Minnaert, Marcel. The Nature of Light and Color in the Open Air. New York: Dover, 1954. Müller, J. Über die organischen Nerven der erectilen männlichen Geschlechtsorgane des Menschen und der Säugethiere. Berlin, 1835.

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Nakajima, Hideto. “Two Kinds of Modification Theory of Light: Some New Observations on the Newton-Hooke Controversy of 1672 Concerning the Nature of Light.” Annals of Science 41, no. 3 (1984): 261–278. Nelson, Alan. “The Falsity in Sensory Ideas: Descartes and Arnauld.” In Interpreting Arnauld, edited by Elmar Kremer, 319–333. Toronto: University of Toronto Press, 1996. Nolan, Lawrence. (Editor) Primary and Secondary Qualities: The Historical and Ongoing Debate. New York: Oxford University Press, 2011. Osler, Margaret J. 2008. “Descartes’s Optics: Light, the Eye, and Visual Perception.” In A Companion to Descartes, edited by Janet Broughton and John Carriero, 124–142. Oxford: Blackwell Publishing, 2008. Palmer, David. “Boyle’s Corpuscular Hypothesis and Locke’s Primary-Secondary Quality Distinction.” Philosophical Studies 29, no. 3 (1999): 181–189. Pessin, Andrew. “Mental Transparency, Direct Sensation, and the Unity of the Cartesian Mind.” In Topics in Early Modern Philosophy of Mind, edited by Jon Miller, 1–37. Dordrecht: Springer/Kluwer Academic Publishers, 2009. Reed, Edward S. “Descartes’ Corporeal Ideas Hypothesis and the Origin of Scientific Psychology.” Review of Metaphysics 35 (1982): 731–752. Reid, Thomas. An Inquiry into the Human Mind. Chicago: University of Chicago Press, 1764/1970. Ribe, Neil M. “Cartesian Optics and the Mastery of Nature.” Isis 88, no. 1 (1997): 42–61. Rorty, Richard. Philosophy and the Mirror of Nature. Princeton: Princeton University Press, 1979. Ryle, Gilbert. The Concept of Mind. Chicago: University of Chicago Press, 1949. Sabra, A.I. Theories of Light from Descartes to Newton. Cambridge: Cambridge University Press Archive, 1967/1981. Schaaf, Fred. Wonders of the Sky. Mineola: Dover Publications, 1983. Schuster, John. Descartes-Agonistes Physico-mathematics, Method & CorpuscularMechanism 1618–33. Dodrecht: Springer Science+Business Media, 2013. Scott, Joseph F. The Scientific Work of Rene Descartes (1596–1650). London: Taylor and Francis, 1976. Shapiro, Alan E. “The Evolving Structure of Newton’s Theory of White Light and Color.” Isis 71, no. 2 (1980): 211–235. ———. (Editor). The Optical Papers of Isaac Newton. Volume 1. The Optical Lectures, 1670–1672. Cambridge: Cambridge University Press, 1984. ———. “Artists’ Colors and Newton’s Colors.” Isis 85, no. 4 (1994): 600–630. Shea, William R. The Magic of Numbers and Motion: The Scientific Career of René Descartes. Canton, MA: Science History Publications, 1991. Simmons, Alison. “Making Sense: The Problem of Phenomenal Qualities in Late Scholastic Aristotelianism and Descartes.” PhD Dissertation, University of Pennsylvania, 1994. ———. “Descartes on the Cognitive Structure of Sensory Experience.” Philosophy and Phenomenological Research 67, no. 3 (November, 2003): 549–579. Singh, Arun Kumar. The Comprehensive History of Psychology. Delhi: Motilal Banarsidass Publishing, 1991. Smith, Norman Kemp. Studies in the Cartesian Philosophy. New York: Macmillan, 1902. Smith, A. Mark. “Descartes’s Theory of Light and Refraction: A Discourse on Method.” Transactions of the American Philosophical Society 77, no. 3 (1987): i–92. ———. “What Is the History of Medieval Optics Really About?” Proceedings of the American Philosophical Society 148, no. 2 (2004): 180–194. ———. From Sight to Light: The Long Passage from Ancient to Modern Optics. Chicago: University of Chicago Press, 2015.

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Smith, Kurt. “Descartes’s Ontology of Sensation.” Canadian Journal of Philosophy 35, no. 4 (2005): 563–584. Straker, Stephen M. “The Eye Made “Other”: Dürer, Kepler, and the Mechanization of Light and Vision.” In Science, Technology and Culture in Historical Perspective, edited by Louis A. Knafla, 7–24. Calgary: University of Calgary, 1976. Strawson, P.F. “Perception and Its Objects.” In Perception and Identity, edited by G.F. MacDonald, 41–60. London: Macmillan, 1979. Tiermersma, Douwe. 1988. “Methodological and Theoretical Aspects of Descartes’ Treatise on the Rainbow.” Studies in History and Philosophy of Science 19, no. 3 (1988): 347–364. Topdemir, Hüseyin. “Kamal Al-Din Al-Farisi’s Explanation of the Rainbow.” Humanity & Social Sciences Journal 2, no. 1 (2007): 75–85. Turbayne, Colin. “The Myth of the Metaphor.” Journal of Aesthetics and Art Criticism 22, no. 2 (1963): 226. Van Hoorn, Willem. As Images Unwind: Ancient and Modern Theories of Visual Perception. Amsterdam: University Press of Amsterdam, 1972. Wade, Nicholas. A Natural History of Vision. Cambridge, MA: MIT Press, 1999. Wallace, William A. The Scientific Methodology of Theodoric of Freiberg. Fribourg, Switzerland: University Press, 1959. Watson, Richard. Representational Ideas from Plato to Patricia Churchland. Dordrecht: Kluwer, 1995. Wells, Norman J. “Material Falsity in Descartes, Arnauld, and Suarez.” Journal of the History of Philosophy 22, no. 1 (1984): 25–50. Werrett, Simon. “Wonders Never Cease: Descartes’s Météores and the Rainbow Fountain.” The British Journal for the History of Science 34, no. 2 (2001): 129–147. Westfall, Richard. “The Development of Newton’s Theory of Colour.” Isis 53, no. 3 (1962): 339–358. Wilson, Margaret D. “Descartes on Sense and ‘Resemblance’.” In Ideas and Mechanism, 10–15. Princeton, NJ: Princeton University Press, 1999a. ———. “Descartes on the Representationality of Sensation.” In Ideas and Mechanism, edited by 69–83. Princeton, NJ: Princeton University Press, 1999b. Wolf-Devine, Celia. Descartes on Seeing: Epistemology and Visual Perception. Carbondale: Southern Illinois University Press, 1993. Yolton, John W. Perceptual Acquaintance from Descartes to Reid. Minneapolis: University of Minnesota Press, 1984. Zemplén, G. A. The History of Vision, Colour, & Light Theories. Bern: Bern Studies in the History and Philosophy of Science, 2005.

4

Descartes’s Quandary

Some of our philosophical problems about concepts are the result of their history. Our perplexities arise not from that deliberate part of our history which we remember, but from that which we forget. A concept becomes possible at a moment. It is made possible by a different arrangement of earlier ideas that have collapsed or exploded. —Ian Hacking, Historical Ontology (2004)1

In this chapter, I describe Descartes’s Quandary, the predicament that Descartes and his contemporaries find themselves in as the result of the Cartesian strand’s criticisms of the Aristotelian strand. I have three goals in describing this quandary. First, I aim to properly characterize the situation that Descartes and his contemporaries find themselves in as the result of their criticisms. I argue that, rather than leaving them well-positioned to take a straightforward position on the nature of color, their criticisms leave them in a philosophical quandary about how to go on thinking about color. The basic problem is that they are left with a pair of hard questions for how to go on thinking about the perception of colors, questions that cannot both be answered in a consistent manner without thereby leading to significant revisions in how they tend to think about what perception can and cannot do. The first goal of this chapter is to properly characterize this situation, so as to make sense of why it leaves them in a philosophical quandary. The second goal is to explain how dispositionalism about color emerges as an apparently attractive view in the context of this quandary. Dispositionalism emerges as an attempt to avoid confronting the difficulties raised by this quandary in a non-revisionary manner. The third goal is to bring out how dispositionalism is ill-equipped to fulfill its promises in this regard.

4.1

DESCARTES’S VACILLATION A philosophical problem has the form: “I don’t know my way about.” —Ludwig Wittgenstein, Philosophical Investigations (1953)2

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In this section, I offer two sorts of evidence for thinking that Descartes finds himself in a philosophical quandary as the result of his criticisms of the Aristotelian strand. First, I give a close reading of one of Descartes’s comments on color, one that usefully illustrates how his criticisms of the Aristotelian strand do not, in themselves, imply a positive view about the nature of color. Second, I compile a series of other comments by Descartes, in which he appears to vacillate between a number of distinct, and incompatible, positions on the nature of color. It will help to begin by outlining the standard story that is often given about the historical context of Descartes’s comments on color. I will then use this standard story as a foil for my close reading. Here is a representative example of the standard story:3 There is a story about seventeenth-century philosophy which goes roughly as follows. Descartes broke with the scholastic tradition by advancing an austere new mechanistic theory of the physical world; according to this theory, bodies intrinsically possess only geometrical properties. Descartes thus stripped the world of many properties which were formerly classified as unambiguously physical. Some of the properties which were left over from the new scientific picture of the world could be safely discarded; the powers, natures, and faculties beloved of the scholastics are obvious examples. But there were many other properties, such as secondary qualities, which could not be treated in this cavalier fashion; they had to be located somewhere, and Descartes invented a new concept of mind in order to accommodate them. (Jolley 1990, 1)4 According to the standard story, Descartes’s austere mechanistic account of the physical world suffices to banish colors to the “dustbin of the mind.”5 Here is how Alison Simmons summarizes the implications of this story for Descartes’s thought about color: [Descartes] excised colors, sounds . . . from the corporeal world . . . [and] relocated [them] in the mind in the form of sensations that do little more than give an ornamental . . . flair to our sense perceptual experience. (Simmons 1999, 347) On the standard story, Descartes relocates colors to the mind, taking them to be nothing more than artifacts of our visual experience, because there is no room for them in the world. There is no room for them in the world because objects in the world intrinsically possess only geometric properties. The standard story usually ends here, but doing so fails to make explicit why there is no room for colors in the world. There is, in other words, a suppressed premise in the standard story, one that is almost never made explicit. The suppressed premise is that colors are not—and cannot be—geometric

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properties of objects. Presumably, the reason that this suppressed premise is rarely made explicit is that it seems obvious that colors are not geometric properties of objects. One of the overarching goals of this book is to make us wary of assuming, in a philosophical context, that second-order claims about the nature of color are obvious. It is worth noting, therefore, that the claim that colors are not geometric properties of objects is not something that either Aristotle or Descartes took to be obvious. Far from it: there are times when both Aristotle and Descartes are fine with describing colors in geometric terms. For example, here is Aristotle explaining the differences between colors in terms of different ratios:6 As the intermediate colours arise from the mixture of white and black, so the intermediate savours arise from the Sweet and Bitter; and these savours, too, severally involve either a definite ratio, or else an indefinite relation of degree, between their components, either having certain integral numbers at the basis of their mixture, and, consequently, of their stimulative effect, or else being mixed in proportions not arithmetically expressible. (Sens. I.4, 442a13–442a17, trans. Beare) And here is Descartes explaining the differences between colors in terms of different ratios: The differences between colors depends . . . solely on the different ratios of forward to rotational movement. (Descartes, AT II 468 [my translation]) These quotations from Aristotle and Descartes do not exhaust everything that they have to say about the nature of color, or what they each think about the relevance of mathematics for understanding color.7 Far from it. But they should make us wary of the suppressed premise in the standard story, the assumption that it is simply obvious that one cannot describe colors as geometric properties of objects. With this initial worry about the standard story in place, we can now give a close reading of a particular comment by Descartes, one that usefully illustrates the quandary he finds himself in as a result of his criticisms of the Aristotelian strand. The comment is from Descartes’s Meteorology, from the section in which he introduces his theory of the rainbow: [S]ince all [colors’] real nature is that they appear, it seems to me a contradiction to say that they are false and that they appear. (Descartes 2001, 338) If we read this comment with the standard story in the background, then it is easy to assume that it relegates colors to the dustbin of the mind. This,

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for example, is how Celia Wolf-Devine reads this comment.8 As she puts her reading, There are . . . hints of a deeper idealism [about color] in this passage. The statement that “all their real nature is to appear” [sic] certainly seems to make of colors something subjective. An “appearance” after all must be an appearance to someone. Colors cannot be identified with the spinning motion of the light particles if “all their real nature is to appear,” since without a perceiver there is no appearance. Descartes also seems to identify colors with their appearance to the perceiver in saying that they cannot appear and be false. If this is so, it would seem that after images (the yellow colors seen by the jaundiced man, etc.) would all be true and, indeed, that all talk of our color perceptions being true or false at all would be ruled out. (Wolf-Devine 1993, 47–48)9 On Wolf-Devine’s reading, Descartes’s comment is intended to take a straightforward position on the nature of color. She takes Descartes’s position to be that colors are merely part of how the world appears to individuals. Accordingly, colors cannot be identified with anything outside of the minds of those individuals; they certainly cannot be identified with purely geometric properties such as the ratio of rotational to forward movement of light particles. Moreover, on Wolf-Devine’s reading, Descartes’s claim that it is “a contradiction to say that [colors] are false and that they appear” commits him to thinking that the very idea of “misperceiving” the colors of things is confused. After all, if colors are merely part of how things appear to individuals, then there is no way for those appearances to be mistaken. In sum, with the standard summary in the background, it is easy to read this comment by Descartes as relocating colors to the dustbin of the mind. The previous two chapters are intended to draw attention to parts of the historical context of Descartes’s comment that are left out of the standard story. (As Ian Hacking puts it, these are “[not] part of our history which we remember, but . . . which we forget” [Hacking 2004, 37].) With these other parts of the historical context in place, it becomes possible to offer a revised reading of this comment, one that challenges Wolf-Devine’s reading. Here is the comment again, this time including the preceding sentence (which Wolf-Devine quotes but does not discuss in her reading): And I cannot approve of the distinction made by the philosophers when they say that there are some true colors, and others which are only false or apparent. For because the entire true nature of colors consists only in their appearance, it seems to me to be a contradiction to say that they are false, and that they appear. (Descartes 2001, 338) If we read this comment in the context of the history of the Descartes’s opposition to the Aristotelian strand, we can see that in the first sentence

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Descartes is expressing his rejection of the Aristotelian distinction between true and apparent colors. According to the Aristotelian distinction, some colors are mere appearances, because our experiences of these colors are brought about by light, whereas other colors are really there, because our experiences of these colors are brought about by the colors themselves. Descartes rejects this Aristotelian distinction on the grounds that it rests upon a false presupposition: namely, that light plays a role in producing our experiences of apparent colors that it does not play in producing our experiences of true colors. As Descartes notes: light plays the same sort of role in both cases. This provides us with an entirely different way of reading Descartes’s comment. On my revised reading, Descartes’s point is not to make a positive claim about the nature of color. Rather, his point is that the Aristotelian strand’s account of what they call “apparent” colors applies equally well to what they call “true” colors. The clause “since all their [i.e., colors’] true nature is that they appear” is intended to point out that experiences of (what the Scholastic Aristotelians call) “true” colors are brought about by light, in just the same way that experiences of (what the Scholastic Aristotelians call) “apparent” colors are brought about by light. It is in this sense that all color experiences are “apparent”: they are all brought about by light. Thus, contrary to Wolf-Devine’s insistence that “[c]olors cannot be identified with the spinning motion of the light particles if ‘all their real nature is to appear,’ ” on my revised way of reading Descartes’s comment, his point is precisely to draw attention to the role that purely geometric properties of light particles play in producing all color experiences. Finally, the clause “it seems to me a contradiction to say that they are false and that they appear” can now be read as pointing out that since the manner in which experiences of (what Scholastic Aristotelians call) “true” colors are produced is the same as the manner in which experiences of (what Scholastic Aristotelians call) “apparent” colors are produced, the very idea that “apparent” colors are “not true” (i.e., false) is self-contradictory. In other words, if the very reason for thinking that “apparent” colors are “apparent” applies equally well to “true” colors, then the very distinction between “true” and “apparent” colors is undermined. Rather than making a positive claim, according to which colors are relocated to the dustbin of the mind, this clause is merely making the negative claim that the Scholastic Aristotelian reason for thinking that “apparent” colors are unreal is unfounded. As Walter Charleton puts this revised way of reading Descartes’s comment, What can remain to interdict our total Explosion of that Distinction of Colours into Real or Inhaerent, and False, or only apparent, so much celebrated by the Schools? For, since it is the Genuine and Inseparable Propriety of Colours, in General, to be Apparent; to suppose that any Colour Apparent can be False, or less Real than other, is an open Contradiction, not to be dissembled by the most specious Sophistry; as

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In short, on my (and Charleton’s) reading of Descartes’s comment, his ultimate point is that it is a mistake to suppose that (what the Scholastic Aristotelians call) “apparent” colors are any less real than (what they call) “true” colors. There is an important difference between these two readings that extends beyond the specifics of this particular passage. The difference concerns what each reading takes the philosophical significance of this passage to be. On Wolf-Devine’s reading, Descartes’s austerely mechanistic account of the physical world implies a positive philosophical position about color: colors are relocated to the dustbin of the mind. Accordingly, it takes the philosophical significance of this passage to be that it allows us to identify Descartes’s positive philosophical position about the nature of colors. On my revised reading, by contrast, Descartes’s specific criticism of a specific aspect of the Aristotelian strand does not leave him with a positive philosophical position about the nature of color. On the contrary, it leaves him with the realization that one aspect of how we used to think about color collapses in upon itself. On my revised reading, what is philosophically significant about this passage is the difficulty it identifies for how to go on thinking about color. That is, far from leaving Descartes with a positive position, the Cartesian strand’s criticism of the Aristotelian distinction between true and apparent colors leaves him in a philosophical quandary about how, exactly, to go on thinking about color. For further evidence that Descartes’s criticism of the Aristotelian strand leaves him in a philosophical quandary, it will help to compile some of Descartes’s other comments on color. Consider, for example, the following four comments: Comment (1): [W]e easily fall into the error of judging that what is called colour in objects is something exactly like the colour of which we have sensory awareness; and we make the mistake of thinking that we clearly perceive what we do not perceive at all. (CSM I 218) Comment (2): [C]olours, smells, tastes and so on, are, I observed, merely certain sensations which exist in my thought. (CSM II 297) Comment (3): [W]hatever you may suppose color to be, you will not deny that it is extended. (CSM I 41) Comment (4): [W]e have every reason to conclude that the properties in external objects to which we apply the terms light, colour, smell, taste, sound, heat and cold—as well as the other tactile qualities and even what are called ‘substantial forms’—are, so far as we can see, simply various dispositions in those objects which make them able to set up various kinds of motions in our nerves . (CSM I 285)

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Reading these passages alongside one another makes it difficult to know how we should characterize Descartes’s positive view on the nature of color. At the most basic level, it is difficult to tell from these comments whether Descartes locates colors inside or outside the mind. Comment (2) seems to locate colors inside the mind, but comment (3) seems to locate colors outside the mind (given that, for Descartes, the defining feature of the world outside the mind is extension). At a more complex level, it is difficult to tell from these comments what sort of philosophical theory of color Descartes holds. Consider, for example, the following standard taxonomy of positions in the philosophy of color:10 Error Theory: the view that all of our beliefs about colors are systematically false. Subjectivism: the view that colors are properties of inner experience. Physicalism: the view that colors are physical properties of external objects. Dispositionalism: the view that colors are dispositions to produce a characteristic sort of visual experience. If we ask ourselves which of these positions Descartes holds, the answer is that he seems to hold all of them—which is obviously problematic. Comment (1) suggests that he holds an error theory of color; comment (2) suggests that he holds a subjectivist theory; comment (3) suggests that he holds a physicalist theory; and comment (4) suggests that he holds a dispositionalist theory. Many who have read Descartes with the intention of identifying which position he occupies in this taxonomy have noted that he appears to vacillate considerably in this regard: Descartes, Boyle, Locke and other writers of the earlier period could vacillate rather unselfconsciously among the views of, say, colors as dispositions or powers to cause sensations, as the mechanistic structures in objects that accounted for the “powers,” or as the sensations themselves. (Wilson 1992, 234) Descartes appears to waver between several different theories of color. (Wolf-Devine 1993, 48) [L]ike many other writers of the seventeenth century Descartes vacillates between taking colors to be dispositions of objects, taking them to be mechanical structures that underlie these dispositions, and taking them to be sensations in the mind. (Cook 1996, 19) In short, many have noted that Descartes appears to vacillate between different positions on the nature of color.11 The almost universal response to this apparent vacillation, however, has been to attempt to explain it away. Almost every commentary on Descartes’s views on color argues that Descartes “really” holds one or another of these positions, and that any

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appearance to the contrary is misleading. An academic cottage industry has emerged, dedicated to identifying Descartes’s “official” position on the nature of color. Thus, some hold that Descartes is an error theorist about color,12 others that he is a subjectivist;13 some that he is a physicalist;14 and others that he is a dispositionalist.15 Almost no one is willing to defend the conclusion that it is a mistake to try to identify Descartes’s “official” position on the nature of color.16 To the extent that this conclusion is even considered, it tends to be summarily rejected on the grounds that it would imply that a philosopher of Descartes’s acuity is guilty of having inconsistent views. As Lawrence Nolan puts this point, “One problem with this conclusion is that, if true, it would mean that Descartes also contradicts himself, for many of these alleged vacillations occur in single works. But this seems implausible” (Nolan 2011a, 82).17 In sum: although standard readings of Descartes on color assume that Descartes must be committed to a single, positive view on the nature of color, there is considerable textual evidence for thinking that he instead found himself in a philosophical quandary with regard to how we should think about color and that he vacillates between a number of distinct, and incompatible, positions in response to this problem. Accordingly, what is needed is an explanation for why Descartes vacillates between these different positions. 4.2 A GENEALOGICAL EXPLANATION FOR DESCARTES’S VACILLATION [P]hilosophical problems are created when the space of possibilities in which we organize our thoughts has mutated. —Ian Hacking, Historical Ontology (2004)18

In this section, I offer a genealogical explanation for Descartes’s vacillation between different positions on the nature of color. I argue that if we understand how Descartes’s criticisms of the Aristotelian strand mutate the space of possibilities for thinking about color, we will be able to understand why he is led to vacillate between these different positions. In other words, understanding the structure of Descartes’s Quandary will allow us to understand his reasons for vacillating. To see the structure of this quandary, consider the situation of someone who recognizes that the discovery that all color experiences are produced by the transduction of light by the retina undermines the basis for the Aristotelian Scholastic distinction between true and apparent colors. This implies that the sense in which Aristotle and the Scholastic Aristotelians think that the colors of things exist independently of light and perceivers is false. Colors simply do not, in that sense, exist independently of light and perceivers. Perhaps, however, there is some other sense in which they do. Descartes’s

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own account of the visual process is able to provide another sense in which color perception involves something that exists independently of perceivers: namely, in terms of geometric properties of the rotating particles of light that produce color experiences.19 I think it is for this reason that we find Descartes making comments like comment (3) above, comments that seem to locate colors outside the mind and seem to identify them with the ratios of rotational to forward motion of light particles. Thus, we find Descartes claiming that “the nature of the color [red] consists only in the fact that the particles of the fine substance that transmits the action of the light have a stronger tendency to rotate than to move in a straight line” (Descartes 2001, 337). This would be the end of this genealogy, and a straightforward way to characterize Descartes’s account of the nature of color, were it not for the fact that choosing to go on talking about color in this manner raises a hard question for how we should think about perception more generally: Hard Question (1): Can perception represent things to us without thereby making us aware of what those things are? If we were to answer this question positively, then the question of how to go on thinking about color in the light of Descartes’s criticisms of the Aristotelian strand would be settled. For example, it would imply that our perceptual experiences of red things represent whatever the external physical causes of red experiences turn out to be. Descartes, however, answers this question negatively, and he here provides a useful illustration of the kind of response that many of us have to the suggestion that redness is identical to a specific ratio of rotational to forward movement in particles of light (or something similar). Significantly, Descartes’s reason for answering this question negatively has nothing whatsoever to do with his criticisms of the Aristotelian strand, nor does it rest upon any sort of claim that is specifically about color or color perception, so one could agree entirely with his criticisms of the Aristotelian strand but disagree with his reason for answering this question negatively. Descartes’s reason for answering this question negatively is (what I will call) his internalism about the content of mental representations.20 For Descartes, the content of a mental representation is determined by facts internal to the thinker of that thought, facts that are available to the thinker just in virtue of having the thought. As Martial Gueroult puts it, “[for Descartes] what constitutes an idea . . . is the character it possesses that an internal investigation reveals, to be manifest to our consciousness as the picture of something external” (Gueroult 1984, 138). This means that if a color experience does not make it possible for a thinker, just in virtue of having that experience, to know that it was caused by a specific ratio of rotational to forward movement in light particles, then that color experience cannot represent that ratio. As Ralph Schumacher puts this aspect of Descartes’s view, “[w]ithin Descartes’s

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theory of mental representation there is no place for ideas which represent something without thereby giving us epistemic access to its nature” (Schumacher 2004b, 89). By answering question (1) negatively, however, Descartes thereby becomes unable to locate colors outside the mind in the rotation of light particles. He is thereby forced to locate colors somewhere else, somewhere where thinkers are in a position to know about them just in virtue of having visual experiences of them. The only place, however, that fits this description is in visual experience itself. It is for this reason that we find Descartes making comments like comment (2) above, comments that locate colors in the mind and that identify them with visual experiences themselves. Thus, we find Descartes claiming that “sensations of tastes, smells, sounds, heat, cold, light, colors, and so on . . . do not represent anything outside our thought” (CSM I 219). Once again, this would be the end of this genealogy, and a straightforward way to characterize Descartes’s account of the nature of color, were it not for the fact that settling on this way of talking about color raises a second hard question: Hard Question (2): Do color experiences represent things outside of thought at all? It is at this point that we come closest to seeing a genuine vacillation in Descartes. It is not at the level of explicitly contradicting himself, of explicitly saying that color experiences both do and do not represent things outside of thought. It is at the more subtle level of going on to say that how we ordinarily talk about colors involves representing them as being something outside of thought.21 For example, Descartes repeatedly uses phrases like “what is called color in objects” (as in comment (1) above, emphasis added) as a way of pointing out that we ordinarily talk as if colors are properties of objects outside of thought.22 Talking as if colors are properties of objects outside of thought, however, is a way of representing them as outside of thought. Descartes’s reason for answering this second question positively, therefore, is (what I will call) his deference to ordinary speech. It is crucial to notice that this deference involves holding on to one key aspect of the Aristotelian strand: the idea that we think of colors as existing outside of thought. At this point, we find Descartes, as the result of answering this second question positively, making comments like comment (1) above, comments that claim to discover the possibility of a systematic sort of error in color experience. Thus, we find Descartes claiming that, [W]hen we suppose that we perceive colours in objects . . . we do not really know what it is that we are calling a colour; and we cannot find any intelligible resemblance between the colour which we suppose to be in objects and that which we experience in our sensation . . . And so we easily fall into the error of judging that what is called colour in objects is

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something exactly like the colour of which we have sensory awareness; and we make the mistake of thinking that we clearly perceive what we do not perceive at all. (CSM I 218) In sum: we can now give a clear articulation of the structure of the quandary that Descartes finds himself in as the result of his criticisms of the Aristotelian strand. The quandary is structured around two hard questions that cannot be answered consistently without thereby leading to significant revisions in how we tend to think about what perception can and cannot do. The first question is whether it is possible for perception to represent things to us without our knowing what those things are. If one answers this first question negatively (as Descartes does, on the basis of his internalism), it becomes difficult to see how one can hold that color perception represents things outside of thought. The second question is whether color experiences represent things outside of thought. If one answers this second question positively (as Descartes does, on the basis of his deference to ordinary speech), it becomes difficult to see why one is not committed to thinking that color experiences are systematically erroneous. The basic structure of the quandary is that it seems impossible to hold both that colors exist outside of thought and that color experiences are not widely erroneous without giving up either internalism or a deference to ordinary speech. In the next section, I argue that dispositionalism first emerges as an appealing position on the nature of color because it seems to provide a way out of Descartes’s Quandary.

4.3

THE EMERGENCE OF DISPOSITIONALISM [M]any of our conceptual misadventures arise precisely because our “linguistic training” has not prepared us adequately for dealing with a vexatious world. —Mark Wilson, Wandering Significance (2006)23

In this section, I give a genealogical explanation for the emergence of dispositionalism about colors, the view that colors are dispositions to produce characteristic sorts of visual experiences. There are four steps to my explanation. First, I make a preliminary point about the use of the word “disposition” in the seventeenth century. Second, I draw a distinction between two forms of dispositionalism about color: light dispositionalism and experience dispositionalism. Both of these forms of dispositionalism are present in the writings of Descartes and his contemporaries, and are sometimes conflated, so it will be crucial to draw a clear distinction between the two. Third, I explain why light dispositionalism is not an attractive solution to Descartes’s Quandary. Fourth, I explain why experience dispositionalism seems to provide a way out of this quandary.

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When discussing dispositionalism in the context of the seventeenth century, it is essential to note that the word “disposition” and its cognates was commonly used in two distinct ways during this period.24 On the one hand, this word was often used to refer to an object’s texture, usually understood in terms of the corpuscular structure of the surface of the object. On the other hand, this word was also used to refer to an object’s powers, usually understood in terms of the object’s ability to bring about certain effects. However, as Peter Anstey notes, these two uses of “disposition” are related in the works of figures such as Descartes, Boyle, and Locke, insofar as these figures hold that “it is in virtue of the ‘disposition’ [texture] of its parts that snow has the ‘disposition’ [ability] to reflect light” (Anstey 2000, 87).25 It is also crucial to draw a distinction between two forms of dispositionalism about color, in terms of two different sorts of effects that an object’s texture has the ability to bring about. First, an object’s texture can have the ability to bring about certain effects on light, in virtue of the ways in which its texture changes the physical character of light by reflecting, refracting, or otherwise modifying it. This is light dispositionalism, the view that color should be identified with a disposition to modify light. The following comment from Boyle suggests such a view:26 [B]ecause there is in the body that is said to be coloured, a certain disposition of the superficial particles, whereby it sends the Light reflected, or refracted, to our eyes thus and thus alter’d, and not otherwise, it may also in some sense be said, that Colour depends upon the visible body. (Boyle 1664 II.3, 10) This passage is especially useful for our purposes, because it makes clear how light dispositionalism is able to locate colors in objects, rather than in the light modified by those objects (and subsequently transduced by the retina). It is able to do this because it identifies color with an object’s disposition to modify light. The second sort of effect that an object’s texture has the ability to bring about is on perceivers. Specifically, it is the ability to bring about certain visual experiences. This is experience dispositionalism, the view that color should be identified with a disposition to bring about color experiences in perceivers. The following comment from Locke suggests such a view:27 [T]he ideas of primary qualities of bodies, are resemblances of them, and their patterns do really exist in the bodies themselves; but the ideas produced in us by these secondary qualities, have no resemblance of them at all. There is nothing like our ideas existing in the bodies themselves. They are in the bodies we denominate from them, only a power to produce those sensations in us; and what is sweet, blue, or warm, in idea, is but the certain bulk, figure, and motion of the insensible parts in the bodies themselves, which we call so. (Locke 1689/1975, II.viii.15)

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This passage is also useful for our purposes, because it makes clear how experience dispositionalism is also able to locate color in objects, rather than in experiences, because it also identifies color with an object’s disposition to bring about color experiences. Both light and experience dispositionalism are well-equipped to accommodate Descartes’s deference to ordinary speech, insofar as both are able to locate colors in objects (rather than in light or experiences). However, light dispositionalism is ill-equipped to accommodate Descartes’s internalism, insofar as it identifies an object’s color with that object’s disposition to modify light. The reason that this entails abandoning internalism is simply that knowing that objects are disposed to modify light is not something that one comes to know just in virtue of having color experiences. As the Aristotelian strand makes manifest, it is perfectly possible to have color experiences without in any way thinking that these color experiences are brought about by objects’ dispositions to modify light. Experience dispositionalism, by contrast, does seem well-equipped to accommodate both Descartes’s deference to ordinary speech and his internalism, insofar as it identifies colors with an object’s disposition to bring about color experiences. The crucial thing to note is that this is something that one can know about an object just in virtue of having color experiences. It is for this reason that experience dispositionalism seems to provide a way out of Descartes’s Quandary.

4.4

PHILOSOPHICAL FALSE FRIENDS How does [this sort of] philosophical problem . . . arise?——The first step is the one that altogether escapes notice. We introduce an analogy but we leave the nature of this analogy undecided. Sometime perhaps we shall know more about [it]—we think. But that is just what commits us to a particular way of thinking about the matter. . . . (The decisive move in the conjuring trick has been made, and it was the very one that we thought quite innocent.)—And now the analogy which was to make us understand . . . falls to pieces. —Ludwig Wittgenstein, Philosophical Investigations (1953)28

In this section, I offer a genealogical critique of experience dispositionalism. To do this, I focus on a specific aspect of how experience dispositionalism was first introduced by Descartes and his contemporaries. Focusing on this aspect will allow us to see how it does not, in fact, do what it was introduced to do, which is to provide a way of holding on to the Aristotelian and Cartesian strands simultaneously. It does not, in this sense, provide us with a way out of Descartes’s Quandary. Rather than offer us a substantive, illuminating solution to this problem, experience dispositionalism ends up offering us nothing more than a merely verbal solution.

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There is an obvious worry that many will have about the form of critique offered in this section, so it is worth addressing that worry up front. The worry is that attending to the context in which dispositionalism first emerged, and using that context to argue that dispositionalism is false, commits the genetic fallacy. The genetic fallacy is the mistake of thinking that errors made in the genesis of an idea must carry over into any subsequent formulation of that idea. There are two reasons why the genealogical critique that follows does not commit the genetic fallacy. First, this genealogical critique does not aim to show that dispositionalism is false. This genealogy is perfectly compatible with dispositionalism being true; the worry it aims to raise is that the only sense in which dispositionalism seems to be true is a completely trivial sense. I am here agreeing with Alex Byrne and David Hilbert’s conclusion that the main problem with dispositionalism “is not falsity, but insipidity” (Byrne and Hilbert 2011, 359). One way to read this genealogy is as an attempt to complement Byrne and Hilbert’s critique of dispositionalism by offering a historical analysis of how and why an insipid view would nonetheless seem informative and useful to so many philosophers. Second, rather than aiming to show that dispositionalism is false, this critique aims to show that it does not, in fact, do what it was introduced to do. It aims to explain, in other words, how and why a completely trivial idea could mistakenly seem to be an informative and useful idea. The goal is to undo a conceptual misadventure by identifying the point at which a philosophically uninformative idea first arose, by giving a genealogical account of why it mistakenly seemed informative in the first place. If this genealogy is able to do that, then it will, at least to that extent, have undermined the most historically significant motivation for dispositionalism. The easiest way to see the problem with dispositionalism is to focus on an analogy that Descartes and many of his contemporaries introduce as a way of motivating how they propose to think about color and color experience in the light of Descartes’s criticisms of the Aristotelian strand. Consider the following quotations from Descartes, Boyle, and Locke: A sword strikes our body and cuts it; but the ensuing pain is completely different from the local motion of the sword or of the body that is cut— as different as colour or sound or smell or taste. We clearly see, then, that the sensation of pain is excited in us merely by the local motion of some parts of our body in contact with another body; so we may conclude that the nature of our mind is such that it can be subject to all the other sensations merely as a result of other local motions. (CSM I 284) [I]n case a pin should chance by some inanimate body to be driven against a man’s finger, that which the agent doth is but to put a sharp and slender body into such a kind of motion, and that which the pin doth is to pierce into a body that it meets with, not hard enough to resist its motion—and so, that upon this there should ensue such a thing as

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pain, is but a consequent that superadds nothing of real to the pin that occasions that pain—so, if a piece of transparent ice be, by the falling of some heavy and hard body upon it, broken into a gross powder that looks whitish, the falling body doth nothing to the ice but break it into very small fragments, lying confusedly upon one another, though, by reason of the fabric of the world and of our eyes there doth in the daytime, upon this comminution, ensue such a kind of copious reflection of the incident light to our eyes as we call whiteness. (Boyle 1991, 35) How secondary qualities produce their ideas. After the same manner, that the ideas of these original qualities are produced in us, we may conceive that the ideas of secondary qualities are also produced, viz., by the operation of insensible particles on our senses. For, it being manifest that there are bodies and good store of bodies, each whereof are so small, that we cannot by any of our senses discover either their bulk, figure, or motion,—as is evident in the particles of the air and water, and others extremely smaller than those; perhaps as much smaller than the particles of air and water, as the particles of air and water are smaller than peas or hail-stones;—let us suppose at present that the different motions and figures, bulk and number, of such particles, affecting the several organs of our senses, produce in us those different sensations which we have from the colours and smells of bodies; e.g., that a violet, by the impulse of such insensible particles of matter, of peculiar figures and bulks, and in different degrees and modifications of their motions, causes the ideas of the blue colour, and sweet scent of that flower to be produced in our minds. It being no more impossible to conceive that God should annex such ideas to such motions, with which they have no similitude, than that he should annex the idea of pain to the motion of a piece of steel dividing our flesh, with which that idea hath no resemblance. (Locke 1689/1975, II.viii.13) Running throughout these quotations is a suggestive analogy. The analogy is between color experience and pain experience.29 The point of the analogy is that pain experience provides a useful model for thinking about the relationship between color experience and color. There are three parts to this model. First, pain experiences do not resemble their external causes. Second, in spite of this lack of resemblance, pain experiences are nonetheless able to make us aware of their external causes. Third, pain experiences are able to make us aware of their external causes without thereby making us aware of whatever paradigmatically primary qualities are present in those external causes. If we consider this analogy in the context of Descartes’s problem, it can seem to provide us with a putative solution. The putative solution is that we should take how we already think about pain experience and use it as a model for thinking about the relationship between color experience and color. Specifically, the model suggests that color experiences can make us

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aware of colors as the external causes of those experiences, without the experiences, in themselves, making us aware of whatever paradigmatically primary qualities are present in those external causes. In short, the analogy seems to provide us with a model for thinking about how Descartes’s problem can be solved in a way that does not require giving up either internalism or a deference to ordinary speech. If the point is to take how we already think about pain experience and use it as a model for thinking about color experience, however, there is a rather significant problem with this analogy. This problem arises as a result of how we tend to think about the relationship between pain experiences and their external causes. Consider, for example, the case of a fire that produces a painful burning sensation in me when I get close to it. The problem is that, as Antoine Arnauld and Pierre Nicole pointed out long ago, “we never say that the fire is in pain” (Arnauld and Nicole 1662/1996, 50). By contrast, we do say that objects are this or that color. The disanalogy that Arnauld and Nicole are highlighting is that although we do not think of pain experiences as making us aware of properties of objects, we do think of color experiences as making us aware of properties of objects.30 Were we to start thinking about color experience on the model of how we already think about pain experience, therefore, we would have to give up on a significant aspect of how we tend to think about color experiences: namely, that they make us aware of properties of objects. This is a preliminary reason for thinking that the proposed analogy between color experience and pain experience will not allow us to hold on to both the Cartesian and Aristotelian strands simultaneously. It does not allow us to do this because it can hold on to internalism only at the cost of forcing us to give up on a deference to ordinary speech. At this point, it is worth considering a rejoinder on behalf of dispositionalism. The rejoinder is to propose that the analogy between color experience and pain experience is only intended to motivate the very idea of it being possible for sensory experiences to make us aware of their external causes without thereby making us aware of anything about those external causes. The problem with this rejoinder becomes clear when we reflect upon how, exactly, we would have to think about colors in the light of this disanalogy. We would have to think about colors as bare dispositions, as dispositions that do not have any categorical basis in the underlying properties of objects. On a bare dispositionalist account of what it is for an object to be red, the object is not disposed to look red in virtue of any underlying properties of the object. It looks red solely in virtue of being disposed to look red. There are two related problems with this sort of bare dispositionalism about colors. The first is that it implies that it would be possible for two objects to be identical in every respect, except that one is disposed to look red and the other is not. But, upon reflection, it seems seriously implausible that the only difference between two objects could be that one is disposed to look red and the other is not, without any further difference between them that

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would explain this difference in dispositions. As Gareth Evans puts it, there is “a deep conceptual prejudice of ours that is offended by dispositional properties without categorical grounds” [Evans 1985, 276]).31 The second, related, problem is that this possibility is incompatible with a basic aspect of the Cartesian strand itself: the idea that there is a one-to-one relationship between the external physical causes of color experiences and color experiences themselves. After all, if bare dispositionalism allows for the possibility of two objects that are identical in every respect, except that one is disposed to look red and the other is not, then one-and-the-same external cause can be disposed to produce different color experiences (in one-and-the-same perceiver, in one-and-the-same set of conditions). This problem for the rejoinder brings out a deeper, more fundamental problem for the very analogy between color experience and pain experience. The problem is that this analogy does not begin to take into account the discovery that motivates the Cartesian strand in the first place: namely, the discovery that light plays a role in producing color experiences that is overlooked by the Aristotelian strand. The clearest way to see this problem is to notice that the relationship between pain experiences and their external causes is a two-place relation, whereas the relation between color experiences and their external causes is a three-place relation. Consider, once again, the case of a pain sensation produced by a fire. In such a case, there are only two factors involved: (i) the fire and (ii) the burning sensation. Now contrast this with a case of seeing the blue color of a pair of blue jeans. In such a case, there are three factors involved: (i) the blue jeans, (ii) the experience of seeing the blueness of these jeans, and (iii) the light that is illuminating these blue jeans.32 The fundamental problem with the analogy between color experience and pain experience is that it assumes, contrary to the discovery that motivates the Cartesian strand in the first place, that blue jeans are disposed to produce experiences of blue in and of themselves. But this is simply false. Whereas fires are disposed in and of themselves to produce experiences of pain, blue jeans are not similarly disposed in and of themselves to produce experiences of blue. At this point, it is easy to wonder why the analogy between color experience and pain experience would be thought to motivate dispositionalism at all. What is needed is an explanation for why the analogy between color experience and pain experience could seem so appealing in spite of this fundamental disanalogy between the two cases. The explanation, I think, is that this situation involves a particularly misleading case of (what I will call) philosophical false friends. The phrase “false friends” (faux amis) is normally used in the context of learning a new language to describe cases in which the new language has words or phrases that look or sound similar to words or phrases in one’s home language, but which mean something quite different. For example, in spite of looking the same, the French word “pain” means something quite different from the English word “pain.” Thus, if one is an English speaker learning French, it is all too easy to make the mistake

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of assuming to that “pain” means the same thing in French that it means in English. Philosophical false friends, by extension, are words or phrases that look or sound similar but mean quite different things in the context of different philosophical theories. As Hacking notes, Sometimes one can find almost the same sentence, in an earlier epoch, as one that is common in a later way of thinking: a precursor indeed! . . . [However] [d]espite the words being the same, so much had happened that the meaning was different (Hacking 2006, xxi). In the context of the interaction of the Aristotelian and Cartesian strands, something like this is going on with regard to the following phrase: Philosophical False Friend: Seeing the colors of things depends on light. This phrase can seem like something that the Aristotelian and Cartesian strands can agree upon. It is, after all, a phrase that they both would endorse. The problem is that it means something completely different in each case. It is, in this sense, an example of a philosophical false friend. In the context of the Aristotelian strand, the phrase “seeing the colors of things depends on light” means that in order to see the colors of things, the transparent medium must actually be illuminated/transparent. In this context, light is simply a condition of the transparent medium, the condition of it actually being transparent. Light does not, in this sense, play any role in bringing about color experiences. It simply makes it possible for colors to bring about color experiences. In the context of the Cartesian strand, by contrast, the phrase “seeing the colors of things depends upon light” means something quite different. It means that color experiences are themselves brought about by the transduction of light by the retina. In this context, light is itself a form of motion, and therefore is itself capable of bringing about color experiences. Having disambiguated this phrase, if we ask ourselves which of these two meanings better fits the analogy between color experience and pain experience, it is, perhaps surprisingly, the Aristotelian meaning. The superficial appeal of the analogy between color experience and pain experience is based upon thinking that we can use the phrase with its Aristotelian meaning at the same time that we can use it in a Cartesian context, without thereby changing what we mean by our words. It is in this sense that the appeal of dispositionalism is based upon a merely verbal agreement, an agreement on nothing more than a particular string of words, regardless of the meanings of those words. In sum: in this section, I have offered a genealogical critique of dispositionalism. My critique aims to show how dispositionalism only appears to be able to hold on to the Aristotelian and Cartesian strands simultaneously. To bring out how dispositionalism glosses over the tensions between these

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two strands, rather than resolving them, I have spelled out the two distinct senses in which each of these strands holds that “seeing the colors of things depends upon light.” My strategy, in other words, has been to bring out how these strands’ merely verbal agreement on this phrase obscures the underlying tension between them.33 NOTES 1. Hacking (2004, 37). 2. Wittgenstein (1973, §123). 3. Influential versions of this standard story include Burtt (1924/1954), Husserl (1936/1970), and Dijksterhuis (1950/1961). 4. Acceptance of this story is widespread enough that it plays the role of a background assumption in many debates in the philosophy of color. For example, consider the following summary statement from Alex Byrne and David Hilbert’s introduction to their anthology of essays on the philosophy of color: Galileo and, following him, an impressive parade of philosophers including Descartes and Locke seem to have thought that modern science straightforwardly shows that physical objects are not colored. (Byrne and Hilbert, 1997, xx) 5. See Nolan and Whipple (2006, 33 fn. 1) for a history of the phrase “dustbin of the mind.” Here is how Nicholas Jolley summarizes this way of reading Descartes (which Jolley endorses): Descartes subscribed to what might be called a dustbin or grab bag conception of the mind. The items that fall under the umbrella of the mental, for Descartes, are whatever is left over from the picture of the world once matter is defined in purely geometrical terms. (Jolley 2000, 57) 6. It is worth noting that the ratios that Aristotle is talking about here are not ratios of different pigments. “The Aristotelian system is not concerned with the behavior of pigments but with the working of colors in nature” (Ackerman 1980, 39). As Alan Shapiro explains: The common painter’s practice of mixing pigments emerged gradually in the late middle ages and did not become widely accepted until the Renaissance, when painters freely experimented with mixed pigments. . . . [T]he idea that white and black are different from the chromatic colors and could not generate them . . . was perhaps the most radical fruit of Renaissance revisions of the concept of color. (Shapiro 1994, 600–601) (For a history of the artistic practice of mixing pigments, see Orna [2013].) The ratios that Aristotle is talking about here are most likely the ratios of the mixture of elements that make up the colors. As Richard Sorabji notes: Aristotle says in the De Sensu that other colours are produced through the mixture of black bodies with white (SS 3, 440a3–b23). The obvious mixture for him to be referring to is the mixture of the four elements, earth, air, fire, and water, which he describes at such length in the De Generatione et Corruptione. All compound bodies are produced ultimately through the mixture of these elements. (Sorabji 1971, 293) For an account of Aristotle’s reasons for identifying different colors with different ratios, see Barker (2007).

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7. For discussion of Aristotle’s attitude towards the use of mathematics in understanding colors, see Sorabji (1972). For discussion of Descartes’s attitude, see Buroker (1991). 8. For evidence that the standard story is in the background of Wolf-Devine’s reading, note that she quotes (approvingly) Dijksterhuis’s account of the standard story at (Wolf-Devine 1993, 33). 9. It is tangential to the main issue here but worth mentioning that Wolf-Devine is clearly conflating two distinct phenomena in this quotation: (i) after images and (ii) the yellow tint that the world is supposed to take on for people with jaundice. After images are the images floating in one’s visual field “following either brief, intense illumination of the eye or prolonged fixation on an illuminated stimulus” (Wade 1998, 159). For example, if one stares at a bright light for a few second and then looks away, one will see an after image of that light floating in one’s visual field. “[T]he yellow colors seen by the jaundiced man” are the yellow colors that jaundiced people are supposed to see permeating the world. First of all, this is not, in fact, how the world looks to people with jaundice. People with jaundice have yellow skin but do not see the world tinted in yellow. (This confusion is old, at least as old as Lucretius’s On the Nature of Things, from the first century B.C.E. [Lucretius 2007].) Second, even in actual cases of people who see the world tinted in yellow (such as when one first puts on a pair of yellow-tinted sunglasses), this is not what after-images are like. That said, the conflation between after-images and seeing the world tinted in yellow does not affect the substance of WolfDevine’s point. 10. This sort of standard taxonomy can be found in Byrne and Hilbert’s introductory essay to their anthology of readings on the philosophy of color (Byrne and Hilbert 1997). 11. Other readers who have noticed this sort of apparent vacillation in Descartes, Boyle, or Locke include Hamilton (1853/1857, 338), Mackie (1976, 15), Troyer (1976, 211), Smith (1990, 237), Maund (1991, 253–263), Blackburn (1993, 280), Nichols (2003, 471–2), Atherton (2004, 28), Stuart (2003, 64), Jacovides (2007, 243), Nolan (2011b, 6), Pasnau (2011, 512–518), and Durt (2012, 49–50). 12. For readings of Descartes as an error theorist, see Costa (1983), Mackenzie (1989/1990), Wilson (1992), Byrne and Hilbert (1997), Stroud (2000), Hyman (2006), and Maund (2012). 13. For readings of Descartes as a subjectivist, see Wells (1984), Cook (1987), Buroker (1991), Field (1993), Menn (1995), Nelson (1996), Keating (1999), Smith (2005), and Downing (2011). 14. For readings of Descartes as a physicalist, see Cottingham (1990), Beyssade (1992), Wolf-Devine (1993), Alanen (1994), Hoffman (1996), Simmons (1999), De Rosa (2007), Buchwald (2008), Hwang (2011), and Gal-Chen and Morris (2012). 15. For readings of Descartes as a dispositionalist, see Jolley (1990), Gaukroger (1995), Thompson (1995), and Dicker (2013). 16. Notable exceptions are Schmaltz (1995 and 1996), Atherton (2004), and Pasnau (2011), although no one offers the genealogical explanation for this vacillation that I give. 17. Others have rejected this conclusion on similar grounds. Here is Simon Blackburn: “It might seem fairly shocking that a philosopher could vacillate over which of these to endorse” (Blackburn 1993, 280). And here is Christoph Durt: “[I]t seems unlikely that philosophers as intellectually sharp as Descartes and Locke [would] blatantly contradict themselves” (Durt 2012, 50). 18. Hacking (2004, 37).

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19. For the purposes of this chapter, the differences between Descartes’s account of the external causes of color experience and a contemporary account do not matter. (For a useful contemporary account, see Nassau [2001].) It is, however, worth noting two significant differences between Descartes’s and contemporary accounts: (i) Descartes assumes that there is a one-to-one relationship between types of external causes and types of color experiences, and (ii) Descartes does not clearly distinguish between the proximal and distal causes of color experiences. 20. Descartes’s most extended articulation and defense of internalism takes place in the First and Third Meditations. For discussions of Descartes’s internalism, see Kemmerling (2004), Schumacher (2004b), and Cassam (2008). 21. For discussion of this aspect of Descartes’s comments on color, see Nolan (2011b). 22. It is in this same sort of context that we find Malebranche reminding us that “[w]e naturally think that color is spread out on the surface of objects” (Malebranche 1674–5/1997, 634) and, more than 330 years later, David Chalmers reminding of the same point: Phenomenologically, it seems to us as if visual experience presents simple intrinsic qualities of objects in the world, spread out over the surface of the object. When I have a phenomenologically red experience of an object, the object seems to be simply, primitively, red. (Chalmers 2010, 398) 23. Wilson (2006, 19). 24. Authors who note the distinction between these two ways of using “disposition” during this period include Wolf-Devine (1993, 48), Anstey (2000, 87), Atherton (2004, 29), Kaufman (2006, 178), and Pasnau (2011, 521). 25. For further discussion of the way in which these two uses “disposition” are related for Descartes and his contemporaries—to the extent that they may not even be sharply distinguished for them—see Rickless (forthcoming). 26. I say “suggests” because Boyle, like Descartes and Locke, appears to vacillate between a number of different positions on the nature of color. I take this apparent vacillation to be evidence that Boyle also finds himself in Descartes’s Quandary. As with Descartes and Locke, this apparent vacillation has led to an academic cottage industry that aims to identify Boyle’s “official” position on the nature of color. For readings of Boyle as a dispositionalist, see Jackson (1929), O’Toole (1974), Ben-Chaim (2004), and Kaufman (2006). For readings of Boyle as a physicalist, see Alexander (1974) and Pasnau (2011). For readings of Boyle as a subjectivist, see Mandelbaum (1974), Keating (1993), and Downing (2011). Curley (1972) and Anstey (2000) both argue that Boyle’s vacillation is real and that it is a mistake to attempt to identify his “official” position on the nature of color. Here is Curley: “Boyle was drawn in different directions on this issue, and . . . he was drawn in different directions for good reasons, even if he was not clear about what those reasons were” (Curley 1972, 447). Here is Anstey: “there is little prospect of offering a fully consistent interpretation of [Boyle’s] doctrine of the sensible qualities without turning a blind eye to important texts” (Anstey 2000, 107). 27. Once again, I say “suggests” because Locke, like Descartes and Boyle, appears to vacillate between a number of different positions on the nature of color. I take this apparent vacillation to be evidence that Locke also finds himself in Descartes’s Quandary. As with Descartes and Boyle, this apparent vacillation has led to an academic cottage industry that aims to identify Lockes’s “official” position on the nature of color. For readings of Locke as a dispositionalist, see Jackson (1929), Yolton (1970), Curley (1972), Wilson (1979),

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28. 29. 30. 31. 32.

33.

Descartes’s Quandary Campbell (1980), Bolton (1983), Lowe (1995), Hyman (2006), and Chappell (2007). For readings of Locke as a physicalist, see Alexander (1974), Troyer (1976), Ayers (1991), McCann (1994), Keating (1998), Jacovides (1999 and 2007), Heil (2005), and Downing (2009). For readings of Locke as a subjectivist, see Berkeley (1710), and Kant (1783/1977). For readings of Locke as an error theorist, see Mackie (1976), Stroud (2000). For a reading of Locke as holding that colors are relations that only exist in the event of being perceived, see Stuart (2003 and 2013). Wittgenstein (1973, §308). It is worth noting that this analogy does not seem to have lost any of its suggestiveness over the years. For a recent invocation of it in this same context, see Langsam (2000). Moreover, we do not think of pain experiences as making us aware of their causes as abiding properties of objects, properties that persist independently of our experience of them. It is at this point that I am inclined to invoke one of John Haugeland’s philosophical maxims, “Don’t get weird beyond necessity” (Haugeland 1998, 120). I am intentionally discussing a case of seeing the color of an ordinary opaque object, and not the case of seeing the color of a light source itself, on the assumption that a large part of the appeal of dispositionalism is due to its apparent ability to account for the (putatively) abiding colors of ordinary opaque objects. It would be disingenuous (and implausibly ad hoc) to insist that dispositionalism is a really only a theory of the colors of light sources and not the colors of ordinary opaque objects. Here is James Conant’s helpful gloss on the sort of strategy I am adopting here: “The aim . . . is to furnish [one’s target] with a perspicuous representation of the various things he might mean by his words in order to show him that, in wanting to occupy more than one of the available alternatives at once and yet none in particular at a time, he is possessed of an incoherent desire with respect to his words” (Conant 2005, 64).

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Jolley, Nicholas. The Light of the Soul: Theories of Ideas in Leibniz, Malebranche, and Descartes. Oxford: Oxford University Press, 1990. ———. “Malebranche on the Soul.” In The Cambridge Companion to Malebranche, edited by Steven M. Nadler, 31–58. Cambridge University Press, 2000. Kant, Immanuel. Prolegomena to Any Future Metaphysics. Edited and translated by James Ellington. Indianapolis: Hackett, 1783/1977. Kaufman, Dan. “Locks, Schlocks, and Poisoned Peas: Boyle on Actual and Dispositive Qualities.” Oxford Studies in Early Modern Philosophy 3 (2006): 153–198. Keating, Laura. “Un-Locke-ing Boyle: Boyle on Primary and Secondary Qualities.” History of Philosophy Quarterly 10, no. 4 (1993): 305–323. ———. “Reconsidering the Basis of Locke’s Primary-Secondary Quality Distinction.” British Journal for the History of Philosophy 6, no. 2 (June 1998): 169–192. ———. “Mechanism and the Representational Nature of Sensation in Descartes.” Canadian Journal of Philosophy 29, no. 3 (1999): 411–429. ———. “The Role of the Concept of Sense in Principles IV, 189–98.” British Journal for the History of Philosophy 12, no. 2 (2001): 199–222. Kemmerling, Andreas. “As It Were Pictures: On the Two-Faced Nature of Cartesian Ideas.” In Perception and Reality: From Descartes to the Present, edited by Ralph Schumacher, 43–68. Paderborn: Mentis, 2004. Langsam, Harold. “Why Colours Do Look Like Dispositions.” Philosophical Quarterly 50, no. 198 (2000): 68–75. Locke, John. Essay Concerning Human Understanding. Edited by P.H. Nidditch. Oxford: Oxford University Press, 1689/1975. Lowe, E.J. Routledge Philosophy Guidebook to Locke on Human Understanding. London: Routledge, 1995. Lucretius. The Nature of Things. Translated by Alicia Stallings. London: Penguin, 2007. MacKenzie, Ann Wilbur. “Descartes on Life and Sense.” Canadian Journal of Philosophy 19, no. 2 (June 1989): 163–192. ———. “Descartes on Sensory Representation: A Study of the Dioptrics.” Canadian Journal of Philosophy, Supplementary Volume 19 (1990): 109–147. Mackie, J.L. Problems from Locke. Oxford: Clarendon Press, 1976. Malebranche, Nicholas. The Search after Truth. Edited and translated by Thomas M. Lennon and Paul J. Olscamp. Cambridge: Cambridge University Press, 1674–5/1997. Mandelbaum, Maurice. “Locke’s Realism.” In Philosophy, Science, and Sense Perception, 1–60. Baltimore: Johns Hopkins Press, 1974. Maund, Barry. “The Nature of Color.” History of Philosophy Quarterly 8 (1991): 253–263. ———. Color. The Stanford Encyclopedia of Philosophy. Edited by E.N. Zalta, 2012. . McCann, Edwin. “Locke’s Philosophy of Body.” In The Cambridge Companion to Locke, edited by Vere Chappell, 56–88. Cambridge: Cambridge University Press, 1994. Menn, Stephen. “The Greatest Stumbling Block: Descartes’ Denial of Real Qualities.” In Descartes and His Contemporaries: Meditations, Objections, and Replies, edited by Roger Ariew and Marjorie Grene, 182–207. Chicago: University of Chicago Press, 1995. Nassau, Kurt. The Physics and Chemistry of Color: The Fifteen Causes of Color. Second Edition. New York: Wiley-Interscience, 2001. Nelson, Alan. “The Falsity in Sensory Ideas: Descartes and Arnauld.” In Interpreting Arnauld, edited by Elmar Kremer, 319–333. Toronto: University of Toronto Press, 1996.

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Nichols, Ryan. “Reid’s Inheritance from Locke, and How He Overcomes It.” Journal of the History of Philosophy 41, no. 4 (2003): 471–491. Nolan, Lawrence. “Descartes on ‘What We Call Color,’ ” In Primary and Secondary Qualities, edited by Lawrence Nolan, 81–108. Oxford, Oxford University Press, 2011a. ———. (Editor) Primary and Secondary Qualities: The Historical and Ongoing Debate. New York: Oxford University Press, 2011b. Nolan, Lawrence and John Whipple. “The Dustbin Theory of Mind: A Cartesian Legacy?” Oxford Studies in Early Modern Philosophy 3 (2006): 33–55. Orna, Mary Virginia. The Chemical History of Color. New York: Springer, 2013. O’Toole, Frederick J. “Qualities and Powers in the Corpuscular Philosophy of Robert Boyle.” Journal of the History of Philosophy 12, no. 3 (1974): 295–315. Pasnau, Robert. “Scholastic Qualities, Primary and Secondary,” In Primary and Secondary Qualities: The Historical and Ongoing Debate, edited by Lawrence Nolan, 41–59. Oxford University Press, 2011. Rickless, Samuel, “Qualities.” In The Routledge Companion to Seventeenth Century Philosophy. Edited by Dan Kaufman. London: Routledge, forthcoming. Schmaltz, Tad M. “Malebranche’s Cartesianism and Lockean Colors.” History of Philosophy Quarterly 12, no. 4 (1995): 387–403. ———. Malebranche’s Theory of the Soul: A Cartesian Interpretation. Oxford: Oxford University Press, 1996. Schumacher, Ralph. “The Content of Experience: Descartes and Malebranche on the Perception of Secondary Qualities.” In Perception and Reality: From Descartes to the Present, edited by Ralph Schumacher, 88–107. Paderborn: Mentis, 2004. Shapiro, A. “Artists’ Colors and Newton’s Colors.” Isis 85, No. 4, 600–630, 1994. Simmons, Alison. “Jesuit Aristotelian Education.” in The Jesuits: Culture, Learning and the Arts, 1540–1773, edited by J.W. O’Malley, S.J. Gauvin Alexander Bailey, Steven J. Harris, and T. Frank Kennedy, 522–537. Toronto: Toronto University Press, 1999. Smith, A.D. “Of Primary and Secondary Qualities.” Philosophical Review 99, no. 2 (1990): 221–254. Smith, Kurt. “Descartes’s Ontology of Sensation.” Canadian Journal of Philosophy 35, no. 4 (2005): 563–584. Sorabji, Richard. “Aristotle on Demarcating the Five Senses.” The Philosophical Review 80, no. 1 (1971): 55–79. ———. “Aristotle, Mathematics, and Colour.” Classical Quarterly 22 (1972): 293–308. Stroud, B. 2000. The Quest for Reality: Subjectivism and the Metaphysics of Colour. Oxford: Oxford University Press. Stuart, Matthew. “Locke’s Colors.” The Philosophical Review 112, no. 1 (2003): 57–96. ———. Locke’s Metaphysics. Oxford: Oxford University Press, 2013. Thompson, Evan. Colour Vision: A Study in Cognitive Science and Philosophy of Science. London: Routledge, 1995. Troyer, John. “Primary Qualities and the ‘Corpuscular Philosophy.’ ” The Southern Journal of Philosophy, 14, no. 2 (1976): 203–211. Wade, Nicholas. A Natural History of Vision. Cambridge, MA: MIT Press, 1998. Wells, Norman J. “Material Falsity in Descartes, Arnauld, and Suarez.” Journal of the History of Philosophy 22, no. 1 (1984): 25–50. Wilson, Margaret. “Superadded Properties: The Limits of Mechanism in Locke.” American Philosophical Quarterly 16, no. 2 (1979): 143–150. ———. “History of Philosophy in Philosophy Today; and the case of the sensible qualities.” The Philosophical Review 101, no. 1 (1992): 191–243.

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Wilson, Mark. Wandering Significance. Oxford: Oxford University Press, 2006. Wittgenstein, Ludwig. Philosophical Investigations. Translated by G. E. M. Anscombe. Third Edition. Oxford: Blackwell, 1973. Wolf-Devine, Celia. Descartes on Seeing: Epistemology and Visual Perception. Carbondale: Southern Illinois University Press, 1993. Yolton, John W. Locke and the Compass of Human Understanding: A Selective Commentary on the Essay. Cambridge: Cambridge University Press, 1970.

5

Moving Beyond the Problem of Color Realism

Several familiar problem areas in the philosophy of perception will be seen to converge in this topic, among them: (i) picking out what is perceived from among the various causal antecedents of the perceiving; (ii) the normativity of objective perception (that is, the possibility of misperception); (iii) the respect in which objective perception depends upon an understanding of what is perceived; (iv) the relevance of language to the possibility of objective perception; and (v) the prerequisite character of the perceiving self or subject. —John Haugeland, “Objective Perception” (1996)1

In this chapter, I explain how we can move beyond the problem of color realism. I do so by arguing that the differences between Cartesian antirealism and Oxford realism turn out to be superficial in comparison to their underlying similarities, and that their similarities include collapsing a distinction that equally well undermines both of their positions. This chapter has five sections. In §5.1, I introduce the target/content distinction, drawn from the work of Robert Cummins (Cummins 1996 and 2010). In §5.2, I argue that Cartesian anti-realism collapses the target/ content distinction, and that this undermines its argument for thinking that there are no colors. In §5.3, I argue that Oxford realism also collapses the target/content distinction, which undermines its response to Cartesian anti-realism. In §5.4, I spell out how the target/content distinction provides us with a way out of Descartes’s Quandary. In §5.5, I conclude by drawing two larger morals from this case study in historicized conceptual analysis. 5.1

THE TARGET/CONTENT DISTINCTION We are looking through my pictures of opera singers. You ask me what Anna Moffo looked like in her prime, and I hand you a picture, which happens to be a picture of Maria Callas. . . . We can distinguish between the target of my representing—Anna Moffo, the

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singer the picture I handed you was supposed to represent on this occasion—and the content of the picture I produced—Maria Callas. —Robert Cummins, “Representation and Indication” (2004)2

In this section, I introduce the target/content distinction, drawn from the work of Robert Cummins, and explain why philosophical positions that collapse this distinction are incapable of making sense of the possibility of either inaccurate or accurate representation. Appreciating the target/content distinction will be necessary for understanding not only what is wrong with both Cartesian anti-realism and Oxford realism, but also how we can escape Descartes’s Quandary. Cummins introduces the target/content distinction in order to explicitly distinguish two aspects of particular acts of representation.3 As he puts this point, [T]here are two senses in which representations are semantically related to the world, the content sense and the target sense, but the distinction is not marked in ordinary vocabulary. The distinction is there . . . but it is marked only by different uses of the same expressions in ordinary language. (Cummins 2010, 136 [emphasis in original]) As a way of bringing out the need for this distinction, consider Figure 5.1, which is used by Robert Venturi, Denise Scott Brown, and Steven Izenour in Learning from Las Vegas to represent the Las Vegas strip. Cummins argues that questions like “What does this map represent?” or “What does this map refer to?” are “systematically ambiguous” (Cummins 2010, 135). To see this ambiguity, consider how there are two distinct sorts of answers that one might give to the question, “What does this map represent?” The first sort of answer identifies what Cummins calls the target of the representation, which is the aspect of the world that the representation aims to represent. In the case of this map, it aims to represent (among other things) the comparative heights of the casino signs along the Las Vegas strip. The second sort of answer identifies what Cummins calls the content of the representation, which is how it represents its target as being. In the case of this map, it represents (among other things) the casino signs on the strip as being a number of different heights: for example, the sign represented by the middle-left “W” is represented as being (roughly) half as tall as the casino sign represented by the middle-right “W.”

Figure 5.1

The Strip (from Venturi et al. 1977, 14)

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It can be hard to recognize the need for the target/content distinction if one thinks only about cases of accurate representation, because if a representation is accurate, its target and content are aligned. Consider, therefore, a case of inaccurate representation. Imagine that this map misrepresents the comparative heights of the casino signs along the Strip in Las Vegas. Imagine, for instance, that in the actual world the casino sign represented by the middle-left “W” is twice as tall as the sign represented by the middleright “W.” In such a case, although the target of this part of the map is the comparative height of a casino sign that is (in fact) twice as tall as its neighbor, the content of this part of the map is that this sign is half as tall as its neighbor. There is, in this sense, a mismatch between the aspect of the world that this map aims to represent and how it represents that aspect as being. It is this sort of mismatch between target and content that allows us to make sense of the possibility of misrepresentation. There are three related respects in which the target/content distinction is crucial for understanding representation. First, it brings out a minimal criterion of adequacy for theories of representation: any adequate theory of representation must give independent accounts of how the targets and contents of representations are determined.4 This is because targets and contents are two distinct aspects of how representations relate to the world. The clearest way to see this is to return to our imaginary case of misrepresentation. The target/content distinction gives us a way of explaining what is going on here: the target is the actual comparative heights of the casino signs; the content includes representing the middle-left sign as half as tall as the middle-right sign; and this is a case of misrepresentation because there is a mismatch between this target and this content. The point is that, in order to make sense of how this sort of mismatch is possible, one must explain how the target and the content of this representation are fixed independently of one another. If they are not, then whatever fixes the one always fixes the other, thereby making mismatches and misrepresentation impossible. Here is how Cummins puts this point: It is precisely the independence of targets from contents that makes error possible. If the content of a representation determined its target, or if targets determined contents, there could be no mismatch between target and content, hence no error. Error lives in the gap between target and content, a gap that exists only if targets and contents can vary independently. (Cummins 1996, 7) Accordingly, a minimal criterion of adequacy for any theory of representation is that it must provide independent accounts of how the targets and contents of representations are determined. Second, the target/content distinction brings out how “representational error” is ambiguous between (what I will call) representational failure and misrepresentation. Representational failure occurs when something that

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someone thinks is a representation fails to represent anything at all. For instance, consider a case in which I make check marks on the left-hand pages of a notebook as a way of recording my weekly beer consumption, but make check marks on the right-hand pages of the same notebook for no particular reason at all. If I were to tell my fiancée that the marks on the lefthand pages represent my weekly beer consumption, she might mistakenly think that the check marks on the right-hand pages represent something else that I am not telling her about. In such a case, her thinking that these marks represent something is not sufficient for it to be the case that they do so. The target/content distinction once again gives us a clear way of explaining what is going on here. In this case, she mistakenly thinks that the marks on the right-hand pages have a target, when they do not. Representational failure (in this sense) is importantly different from misrepresentation. Misrepresentation occurs when a representation represents something as being a certain way when it is not, in fact, that way. As Cummins puts this point (echoing Jerry Fodor), misrepresentation “occurs when a representation is applied to something that it is not true of, for example, when one applies a representation of a horse to a cow” (Cummins 2010, 136 [emphasis in original]). The point is that misrepresentation actually presupposes two distinct forms of representational success: in order for the middle-left “W” to misrepresent the height of the sign it represents, it must succeed at having both a target and a content. Although representational failure can occur when something fails to have a target at all, misrepresentation can occur only when a representation has a target and a content, and its target is not the way that its content represents it as being. It is for this reason that representational failure and misrepresentation are distinct forms of representational error. Third, the target/content distinction brings out how accurate representation involves three achievements: (i) having a target, (ii) having a content, and (iii) having the content match the target. Inaccurate representation (misrepresentation) involves achieving the first two of these, and trying to achieve, but not succeeding at achieving, the third. The point is that any theory of representation that collapses the target/content distinction is precluded from explaining the possibility of either accurate or inaccurate representation. This is because if this distinction is collapsed, there is no way to explain how a representation’s content either matches or mismatches its target. In sum, the target/content distinction identifies two ways in which representations are semantically related to the world, and any adequate account of representation must explain how targets and contents are determined independently of one another. As Cummins puts this point, “[i]t is precisely the failure to allow for these two factors that has made misrepresentation the Achilles heel of current theories of representation” (Cummins 1996, 7). In the next two sections, I argue that the failure to acknowledge the target/ content distinction is the Achilles heel of both Cartesian anti-realism and

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Oxford realism. They both fail to achieve their respective goals because they both collapse the target/content distinction.

5.2

THE PROBLEM WITH CARTESIAN ANTI-REALISM Even if I do not refer my ideas to anything outside myself, there is still subject-matter for error . . . For example, I may say whiteness is a quality; and even if I do not refer this idea to anything outside myself—even if I do not say or suppose that there is any white thing—I may still make a mistake in the abstract, with regard to whiteness itself and its nature of the idea I have of it. —René Descartes, Conversation with Burman (1648)5

In this section, I identify a fundamental problem for Cartesian anti-realism. Cartesian anti-realists aim to convict color experiences of being inherently guilty of error. The problem is that the argument they adopt for achieving this aim ends up collapsing the target/content distinction and, in so doing, has the consequence of making it impossible for it to convict color experience of error at all. In order to bring out the self-undermining nature of their argument, I draw upon a series of influential passages from Descartes’s Meditations and Principles of Philosophy. I use these passages to bring out the specific way in which the argument for Cartesian anti-realism collapses the target/content distinction and thereby undermines itself. Recall that Cartesian anti-realists aim to show that color experience is guilty of a distinctive sort of error, one that is supposed to pervade all of our thoughts about color, such that it suffices to justify the blanket conclusion that “our color ascriptions are false and our color sensations illusory” (Landesman 1993, 104). Cartesian anti-realists do not proceed by going through individual color experiences and showing that they are individually guilty of error. Rather, they aim to show that a systematic kind of representational error originates in our very conception of colors. They hold that the reason that “objects do not have the colour properties that our experiences represent them as having” is that “[t]here are no colours in the world, so conceived” (Maund 2006, 248). It is in this sense that they think that “[t]he best interpretation of colour experience ends up convicting it of widespread and systematic error” (Boghossian and Velleman 1989, 82). This accusation of widespread and systematic error might seem surprising when one considers mundane observations about color experience, such as the following: There are two books on my desk: Phillip Bricker and R. I. G. Hughes’s Philosophical Perspectives on Newtonian Science and Nelson Goodman’s Languages of Art. When I look at the Bricker and Hughes volume, its cover looks blue, and when I look at the Goodman volume,

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its cover looks red. I am reliably able to distinguish the books in virtue of having these color experiences, as well as reliably able to re-identify them in the same way. Importantly, neither Descartes nor any of the contemporary Cartesian antirealists introduced in Chapter One would dispute any of these mundane observations. They all concede that color experiences allow us to discriminate and re-identify objects in the external world. Descartes would happily make a series of further concessions. He would note that my different color experiences correspond to real differences in the book covers.6 He would note that my different color experiences have identifiable physical causes.7 He would note that my different color experiences function as “natural signs” of these physical causes.8 And he would note that my ability to discriminate and re-identify these books by seeing their colors is a clear example of how sensory experiences help us to navigate the world.9 These mundane observations are helpful, for two reasons. First, they bring out how Cartesian anti-realists are committed to showing that color experience is inherently guilty of misrepresentation, not representational failure. Representational failure is failing to represent anything at all. But holding that color experiences fail to represent anything at all is manifestly incompatible with the concession that color experiences allow us to discriminate and re-identify objects in the external world. Thus, Cartesian anti-realists are committed to showing that color experience is inherently guilty of misrepresentation.10 Second, they foreground a difficulty that we should keep in mind as we consider the argument for Cartesian anti-realism. The difficulty is understanding how, if Descartes concedes that color experiences allow us to reliably discriminate and re-identify objects in the external world, he can also hold that color experience is inherently guilty of widespread and systematic error. In short, given his concessions, how can Descartes also hold that “[t]he epistemological bottom line . . . is that [color] sensations are inherently non-veridical and can play no role in the mind’s search after truth” (MacKenzie 1990, 125)? As Lilli Alanen puts this difficulty for Descartes, “if sensory ideas can be used as (mostly) reliable signs instituted by nature for pragmatic (biological) purposes, they can hardly be inherently false” (Alanen 2003, 160 [emphasis in original]). Descartes’s response to this difficulty is a useful illustration of the Cartesian anti-realist strategy in general. Descartes proposes that our thought about color is, in itself, guilty of a distinctive sort of representational error, one that he calls “material falsity.”11 Here is how Descartes introduces the idea of material falsity: [With regard to things such as] light and colours, sounds, smells, tastes, heat and cold and the other tactile qualities, I think of these only in a very confused and obscure way, to the extent that I do not even know

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Moving Beyond the Problem of Color Realism whether they are true or false, that is, whether the ideas I have of them are ideas of real things or of non-things. For although, as I have noted before, falsity in the strict sense, or formal falsity, can occur only in judgments, there is another kind of falsity, material falsity, which occurs in ideas, when they represent non-things as things. (CSM II 30)

Here is how he elaborates on this idea soon after: Such ideas obviously do not require me to posit a source distinct from myself. For on the one hand, if they are false, that is, represent nonthings, I know by natural light that they arise from nothing—that is, they are in me only because of a deficiency and lack of perfection in my nature. If on the other hand they are true, then since the reality which they represent is so extremely slight that I cannot even distinguish it from a non-thing, I do not see why they cannot originate from myself. (CSM II 30) And here is how he later clarifies this idea: [A]s for the confused ideas of gods which are concocted by idolaters, I see no reason why they too cannot be called materially false, in so far as they provide idolaters with subject-matter for false judgments. . . . It is easy to show by means of examples that some ideas provide much greater scope for error than others. Confused ideas which are made up at will by the mind, such as the ideas of false gods, do not provide as much scope for error as the confused ideas arriving from the senses, such as the ideas of colour and cold (if it is true, as I have said, that these ideas do not represent anything real). (CSM II 163) Upon first reading these passages, it can seem like there is a straightforward way of understanding what Descartes is saying: namely, that he thinks that our thought about color is systematically false because it does not correspond to anything in the world. However, if one reads these passages in the context of some of Descartes’s other views, things quickly become confusing. First, the passages seem to conflict with Descartes’s other statements about falsity. The passages above suggest that Descartes thinks that there is a kind of falsity that is exhibited by color experiences taken by themselves. This is confusing because Descartes also holds that ideas, taken by themselves, cannot be true or false. As he puts it, “as far as [my] ideas are concerned, provided they are considered solely in themselves and I do not refer them to anything else, they cannot strictly speaking be false” (CSM II 26). Moreover, when he introduces “formal falsity” earlier in the same text, he often refers to it simply as “falsity” (or, “falsity properly understood”) and he claims that merely entertaining an idea of something that does not exist (such as a chimera) is not enough for that idea to be false. In order for

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this idea to be false, I must mistakenly judge that this idea “resemble[s], or conform[s] to, things located outside me” (CSM II 26). Whereas, if I merely entertain such ideas on their own, “without referring them to anything else, they could scarcely give me any material for error” (CSM II 26). The problem is that Descartes nonetheless wants to claim that color experiences, taken by themselves, give us “subject-matter for false judgments” (CSM II 163). Thus, a first confusing aspect of Descartes’s idea of material falsity is that it appears inconsistent with his other statements about falsity. Second, the passages seem to conflict with Descartes’s other statements about the causes of color experiences. The passages above suggest that color experiences are not caused by anything. This is confusing because, as we have seen, Descartes holds that color experiences have external causes. Moreover, he also holds that “in order for a given idea to contain such and such objective reality [i.e., representational content], it must surely derive it from some cause which contains at least as much formal reality [i.e., actual existence] as there is objective reality in the idea” (CSM II 28–9). The problem is that if color experiences “arise from nothing” (CSM II 30), then it is hard to see how they can have any representational content. And if they do not have any representational content, they can hardly “represent non-things as things” (CSM II 30). Thus, a second confusing aspect of Descartes’s idea of material falsity is that it is either a direct contradiction of what he holds about the external causes of color experiences, or it implies that color experiences do not have any representational content at all, in which case they cannot be guilty of misrepresentation. Third, the passages seem to conflict with Descartes’s other statements about what makes ideas about what they are about in the first place. The passages suggest that some of our ideas (e.g., color experiences) inherently misrepresent the nature of the things that they are about. This is confusing because, given the other things Descartes says about ideas, it would seem to be impossible for them to do this. At this point, there are three things worth remembering about what Descartes says about ideas. First, he holds that “there can be no ideas which are not as it were of things” (CSM II 30) and, second, he holds that “insofar as different ideas represent different things, it is clear that they differ widely” (CSM II 28). The first statement suggests that he thinks that all ideas are representational, and the second suggests that he thinks that ideas are individuated in terms of what they represent. Third, he holds that what a particular idea represents is determined by how the thinker thinks about the nature of the thing represented. (This is another way of putting his internalism about the content of mental representations, introduced in Chapter Four.) The problem is that these three commitments make it impossible for an idea to inherently misrepresent the nature of what is it about. To see this, consider the case of someone having a certain idea, ideac, and ask yourself whether this idea could misrepresent chimeras as having the features of minotaurs. The important thing to remember is that the representational content of

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ideac is what determines which idea it is, and the representational content of this idea is determined by how the thinker of this idea thinks about the nature of the thing represented by this idea. Thus, if I am thinking ideac and I think about the nature of the kind of thing represented by ideac as having the head of a bull and the body of a man, then I cannot be misrepresenting chimeras as minotaurs, because I am simply thinking about minotaurs! Even if I am standing in front of a chimera when I have this thought, given what Descartes says about how ideas are individuated, I am nonetheless still thinking about minotaurs (assuming that I am still thinking about the nature of the thing represented by this idea as something that has the head of a bull and the body of a man). Thus, the third confusing aspect of Descartes’s idea of material falsity is that it appears inconsistent with his own account of what makes ideas about what they are about in the first place. I am far from the first to note that Descartes’s passages on material falsity seem confusing if they are read in the context of his other commitments. The idea of material falsity has been called “a model of confusion confounded” (Wilson 1978, 97), “a headache or a red herring, if not a plain inconsistency” (Beyssade 1992, 5), and “obscure in the extreme . . . [such that] one might be forgiven for thinking that Descartes [is] guilty . . . of incoherent thought” (Wee 2006, 6). In sum, “[m]any contemporary Cartesian scholars find Descartes’s views on material falsity hopelessly confused” (Scholl 2005, 55).12 Although it is widely recognized that Descartes’s idea of material falsity seems confusing, the most common response to this confusion has been to attempt to explain it away by offering a reading of these passages that aims to make the idea of material falsity consistent with Descartes’s other commitments.13 As I did with Descartes’s apparent vacillation over the nature of color, however, I propose to focus on this confusion itself, as a way of drawing a larger philosophical moral. I think the right question to ask ourselves is this: what, exactly, is missing from Descartes’s account such that this confusion seems inevitable? What is missing from Descartes’s account is the target/content distinction.14 To see this, consider once again the example of ideac. The reason that Descartes’s own formulation of material falsity cannot explain how ideac could misrepresent chimeras as minotaurs is that Descartes’s internalism leads him to collapse the distinction between the targets and contents of ideas. Descartes’s internalism commits him to thinking that what a particular idea is about is determined by how the thinker (of the idea) thinks about the nature of what the idea is about. This means that, for Descartes, the content of an idea (i.e., how the thinker of the idea thinks about the nature of the thing represented by the idea) determines its target (i.e., what the idea aims to represent). The problem is that if the content of an idea determines its target, then it becomes impossible to explain how that idea can misrepresent anything. To see what is missing here, consider what happens if we explicitly introduce a target/content distinction to the discussion, deny that

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the content of an idea determines its target, and give independent accounts of how each of these aspects of ideac are determined. It then becomes possible to see how ideac can misrepresent chimeras as minotaurs. If we are able to give independent accounts of how the target and content of ideac are determined, then the target of ideac could be fire-breathing creatures with the body of a lion and three heads, while the content of ideac could be creatures with the head of a bull and body of a man. The problem is that it becomes possible to explain this misrepresentation only if we deny Descartes’s claim that the content of an idea determines its target and, unlike Descartes, give independent accounts of how each of these aspects of representations are determined. In order to see just how problematic collapsing the target/content distinction is for Cartesian anti-realism, consider the following pair of passages from the Principles of Philosophy: [W]e must be very careful to note that pain and colour and so on are clearly and distinctly perceived when they are regarded merely as sensations or thoughts. But when they are judged to be real things existing outside our mind, there is no way of understanding what sort of things they are. (CSM I 217) [W]e easily fall into the error of judging that what we call color in objects is entirely similar to the color which we sense, and thus of supposing that we clearly perceive what we in no way perceive. (CSM 1 218) Upon first reading these passages, it can seem that Descartes is clearly providing Cartesian anti-realism with a possible way in which color experience could be guilty of systematic representational error. Here is how Barry Maund characterizes this sort of error: Descartes’ view, as I understand it, is and indeed must be, that with respect to our color-experiences we can and should distinguish between the-color-as-the-representational content of our experience and the color-as-an-inherent-feature-of the experience. Physical bodies have color in the first sense but do not have color in the second sense. Nevertheless, he contends, there is a natural tendency for us to think that physical bodies do have colors in this second sense . . . [and] that view is incorrect. (Maund 1991, 255 [emphasis in original]) The problem with this reading of Descartes, however, is that if one collapses the target/content distinction, then it becomes impossible to explain how we might have this “natural tendency” at all. To see the problem, consider what happens when we try to spell out Maund’s account with regard to an example of a particular color experience. There are three parts to this example: the color experience itself (call this experiencec), the property of the object that this experiences aims to represent (call this

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colortarget, i.e., “the-color-as-the-representational content of our experience”), and how the experience represents that property of the object as being (call this colorcontent, i.e., “the color-as-an-inherent-feature-of the experience”). Maund claims that Descartes holds that we have a “natural tendency” to have experiences like experiencec that misrepresent colortarget as colorcontent. The problem is that by Descartes’s own lights, experiencec cannot do this. Descartes holds that the content of an experience determines its target. This means that experiencec does not, and cannot, in any sense aim to represent colortarget. So it cannot misrepresent colortarget as colorcontent. All that experiencec is capable of representing (in any sense) is colorcontent. Here is how Ralph Schumacher summarizes this problem: On the one hand, Descartes claims that the content of our ideas of secondary qualities is exhausted by the phenomenal content of our sensations. If we clarify the content of these ideas, we find out that we have a clear and distinct apprehension only of the qualitative character of certain sensations, but not of the nature of their causes. But on the other hand, Descartes also claims that our ideas of secondary qualities represent something existing without the mind—namely, certain combinations of primary qualities. These two claims are incompatible, because, according to his theory of ideas, the intentional content of ideas determines which objects are represented by them. (Schumacher 2004, 100 [emphasis in original]) There is a general philosophical moral to draw from this problem for the argument for Cartesian anti-realism. The moral is that if one collapses the target/content distinction, then it becomes impossible to explain how color experiences can represent anything at all, inaccurately or accurately. This should make it clear why the target/content distinction needs to be explicitly introduced into the discussion of whether color experience is guilty of widespread and systematic representational error. The problem is that once this distinction is explicitly introduced into this discussion, whatever apparent plausibility the Cartesian anti-realist position has vanishes. In sum: the problem with Cartesian anti-realism is that the argument for it is self-undermining. It aims to convict color experiences of being inherently guilty of error. But, in its effort to do so, it collapses the target/content distinction. This has the consequence of making it impossible for Cartesian anti-realists to make sense of how color experiences might inaccurately (or accurately) represent anything at all.

5.3

THE PROBLEM WITH OXFORD REALISM A conception of what it is for something to have a given secondary quality is not separable from a conception of what it would be like to

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establish that that is so in the most direct way: that is, by a suitable sensory experience in suitable circumstances (say, having the thing look red to one in appropriate lighting conditions). That is what it means to say that secondary qualities are essentially phenomenal qualities. —John McDowell, “Mathematical Platonism and Dummettian Anti-Realism” (1989)15

In this section, I identify a fundamental problem for Oxford realism. Oxford realists aim to absolve color experiences from being inherently guilty of error. The problem is that the argument they adopt for achieving this aim ends up collapsing the target/content distinction and, in so doing, has the consequence of making it impossible for them to credit color experience with being accurate. In order to bring out the self-undermining nature of this argument, I draw upon a series of passages from Gareth Evans’s, John McDowell’s, and Colin McGinn’s arguments for Oxford realism. I use these passages to bring out the specific way in which the argument for Oxford anti-realism collapses the target/content distinction and therefore undermines itself. Recall that Oxford realists aim to show that color experiences cannot be guilty of widespread and systematic representational error. They aim to do this by showing that “a certain kind of skepticism about secondary qualities is incoherent” (McGinn 1983, 12). They argue that Cartesian anti-realists’ blanket skepticism about secondary qualities (including colors) rests upon “a gratuitous slur on perceptual ‘common sense’ ” (McDowell 1985, 113). They argue against this slur on the grounds that it overlooks the “intrinsic tie between color and sentience” (Hyman 2006, 17). It is because of this intrinsic tie between being colored and looking colored that Oxford realists hold that color experiences cannot be guilty of widespread and systematic representational error. In this section, I argue that Oxford realism is a mistaken way of responding to Cartesian anti-realism. My argument in this section does not focus on Oxford realism’s commitment (shared with Cartesian anti-realism) to the false assumption that our ordinary concept of color involves a single, univocal strand of thought that is ahistorically fixed and unrevisable. Rather, it focuses on a second surprising parallel between these putatively opposed positions: a tendency to collapse the target/content distinction. In order to bring out this second parallel, I focus on an apparent vacillation within Oxford realists between apparently distinct claims about how we can, and cannot, conceive of colors. Once again, I think there is a philosophical moral that we can draw from this apparent vacillation. As noted in Chapter One, the Oxford realist argument against Cartesian anti-realism rests upon a pair of related claims about how we ordinarily conceive of color. Oxford realists hold, first, that we ordinarily think of colors in relational terms, as dispositions to produce characteristic sorts

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of visual experiences, and, second, that it is simply incoherent to think of colors as intrinsic properties of objects that are ontologically on par with shapes. For this reason, Oxford realists are committed to denying the “intelligibility of a non-dispositional concept” (Evans 1985, 273 fn. 30 [emphasis in original]) of color. Given this commitment, however, it is striking to come across passages such as the following (from Gareth Evans), which appear to vacillate on how we can conceive of color: For an object to have [what Evans has just called a “sensory property” such as color] is for it to be such that, if certain sensitive beings were suitably situated, they would be affected with certain experiences, though this property may, in its turn, be identified with what we should normally regard as the ground of the disposition. However, in the first instance, a sensory property is a dispositional property. (Evans 1985, 269) In response to this passage, it is reasonable to wonder what, exactly, Evans thinks. Does he, or does he not, think that a non-dispositional concept of color is coherent? His argument against Cartesian anti-realism rests upon the claim that our ordinary thought about color is exhausted by thinking about colors in dispositional terms. As he puts this claim, “[a]ll it can amount to for something to be red is that it be such that, if looked at in the normal conditions, it will appear red” (Evans 1985, 272 [emphasis added]). This appears to be why he thinks that colors are “propert[ies] of experience” (Evans 1985, 272 [emphasis removed]). The problem is that he also seems to allow for the possibility that colors can “be identified with what we should normally regard as the ground of the disposition” and that the grounds of these dispositions are themselves “capable of being characterized independently of the disposition[s]” (Evans 1985, 275). If he allows for this possibility, however, it is hard to see how he can claim that our ordinary thought about color is exhausted by thinking about colors in dispositional terms. In short, Evans appears to vacillate on whether he thinks a nondispositional concept of color is, or is not, coherent. Significantly, this same apparent vacillation also appears in John McDowell’s defense of Oxford realism. Consider the following passage: [A]n object’s being red is understood as obtaining in virtue of the object’s being such as (in certain circumstances) to look, precisely, red. . . . I have written of what property-ascriptions are understood to be true in virtue of, rather than what they are true in virtue of. No doubt it is true that a given thing is red in virtue of some microscopic textural property of its surface; but a predication understood only in such terms—not in terms of how the object would look—would not be an ascription of the secondary quality of redness. (McDowell 1985, 111–112)

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Once again, as with Evans, the question is whether McDowell thinks a non-dispositional concept of color is, or is not, coherent. In this passage, McDowell introduces a distinction between two ways in which we can understand what it is for a particular object to be red: a dispositional and non-dispositional way. The dispositional way is given in secondary quality terms, in terms of “the object’s being such as (in certain circumstances) to look” a certain way. The non-dispositional way is given in primary quality terms, in terms of “some microscopic textural property of its surface.” The confusion arises at the end of the passage, where it is unclear whether the final sentence is meant to undermine what was said earlier, or not. (Evans’s passage is similar in this regard.) The problem is that the final sentence in McDowell’s passages is ambiguous between two readings, only one of which supports Oxford realism. In this final sentence, McDowell claims that “a predication [of “red”] understood only in [primary quality] terms . . . would not be an ascription of the secondary quality of redness.” On a first reading, McDowell is claiming that understanding an object as being red in primary quality terms would not involve understanding it as being red (in any sense). This reading supports the Oxford realist claim that a non-dispositional understanding of redness is incoherent. On a second reading, McDowell is claiming that understanding an object as red in primary quality terms would not be the same as understanding what it is for something to be red in secondary quality terms. This reading does not support Oxford realism at all, however, because it manifestly does not preclude understanding an object as red in primary quality terms. It merely claims that there are two ways of understanding an object as red: the primary and secondary quality ways. The problem is that McDowell’s own argument against Cartesian anti-realism rests upon the claim that it is incoherent to propose that we can understand an object as red in primary quality terms. It is for this reason that McDowell, like Evans, appears to vacillate on whether he thinks a non-dispositional concept of color is, or is not, coherent. McDowell himself does not elaborate on this apparent vacillation in his thought. But he does end this passage by citing an illuminating section from Colin McGinn’s own defense of Oxford realism. Towards the end of the section McDowell cites, McGinn offers the following proposal for how we should think about the relationship between colors, understood as dispositions, and the grounds of those dispositions: [I]n the case of secondary qualities, the most we should demand is that for any instantiation of such a quality there should be some ground in the object which explains (in conjunction with certain other facts) the perceiver’s experience; we should not expect the stronger proposition that there is one such ground for any instantiation of the quality. (McGinn 1983, 14 [emphasis in original])

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McGinn’s proposal is that it is possible to hold on to the Oxford realist claim that “colours are intrinsically dispositional” (McGinn 1983, 14 [emphasis in original]) while at the same time conceding that these dispositions have grounds in objects that can be independently characterized (as Evans and McDowell suggest). He does this by pointing out that this concession need only take the form of holding that, for any particular experience of an object’s color, there is something in the object (in conjunction with other facts about the world and the perceiver) that causally explains the perceiver’s experience. For many contemporary readers, McGinn’s proposal might sound familiar, insofar as it sounds like a color version of the sort of token-identity theory pioneered by Donald Davidson (and others) in the philosophy of mind (Davidson 1970). However, given the preceding section, I think we are in a position to see how the view that McGinn is proposing is also surprisingly similar to Cartesian anti-realism. Recall three core features of Descartes’s own argument for Cartesian anti-realism:16 Feature one: Descartes concedes that for any particular experience of an object’s color, there is something in the object (in conjunction with other facts about the world and the perceiver) that causally explains the perceiver’s experience. Feature two: Descartes holds that it would be a mistake to think that this color experience represents this external cause in the object. Feature three: Descartes’s argument for thinking that this color experience does not represent this external cause rests upon collapsing the target/content distinction, because it holds that the content of a color experience determines the target of that experience. This makes it impossible to see how color experiences are capable of inaccurately, or accurately, representing anything at all. All three of these features are explicitly present in McGinn’s version of Oxford realism. Feature one is present because McGinn holds that for any particular experience of an object’s color, there is something in the object (in conjunction with other facts about the world and the perceiver) that causally explains the perceiver’s experience. Feature two is present because McGinn holds that it would be a mistake to think that this color experience represents this external cause. As he puts it, “[c]olours, for example, are not to be identified with wavelengths of the spectrum” (McGinn 1983, 12–13). For McGinn, the properties represented by color experiences are not whatever properties causally explain perceivers’ color experiences; as he puts it, “secondary properties do not explain our perceptions of them; primary properties are what do that” (McGinn 1983, 15).

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Feature three is present because McGinn’s argument for thinking that this color experience does not represent this external cause rests upon collapsing the target/content distinction. This is the result of the combination of the following two claims: (i) that “[color] experiences necessarily consist in representing the world as having certain qualities” and (ii) that “we [Oxford realists] are explaining the instantiation of [these qualities] in terms of the production of experiences with a certain intentional content” (McGinn 1983, 7). Consider, once again, our example of experiencec. McGinn, like Descartes, holds that experiences are individuated in terms of what they represent. As he puts it, “[color] experiences are distinguished by their representational content” (McGinn 1983, 7). McGinn also holds that the property of an object that a color experience aims to represent (its colortarget) depends upon how it represents that property of being (its colorcontent). As he puts it, “experiential facts are constitutive of the presence of the quality in question” (McGinn 1983, 8 [emphasis in original]). (This should remind us of McDowell’s claim that colors are “essentially phenomenal qualities” [McDowell 1998, 357].) This means that McGinn holds that the colortarget of experiencec is constituted by the colorcontent of that experience. It is in this sense that Oxford realists, like Cartesian anti-realists, collapse the target/content distinction. The problem is that this makes it impossible to see how color experiences are capable of accurately (or inaccurately) representing at all. Having noted these three surprising similarities between Cartesian antirealism and Oxford realism, what differences remain between these two putatively opposed views? The most obvious difference is that they give different accounts of how we ordinarily conceive of color. But even this difference is not enough for these views to be genuinely opposed, because their different accounts actually conflict only on the assumption that there is a single, univocal way in which we ordinarily conceive of colors. If, however, the genealogy offered in the preceding three chapters is correct, then this assumption is baseless. Accordingly, this difference between Cartesian anti-realism and Oxford realism turns out not to be enough for them to be genuinely opposed. This is the first reason why we should move beyond the problem of color realism. There is, simply put, no substantive disagreement between Cartesian anti-realism and Oxford realism. There is, however, one further difference between Cartesian anti-realism and Oxford realism that is worth mentioning: Oxford realists aim to show that color experiences are not guilty of widespread and systematic representational error, on the grounds that they hold that color experiences reveal properties of objects to us, not merely properties of experience (pace Evans). Even this difference between Oxford realism and Cartesian anti-realism, however, becomes markedly less significant once we make explicit the sort of properties of objects that Oxford realists think that color experiences are able to reveal to us. McGinn’s defense of Oxford realism is especially helpful

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in this regard, because he is extremely clear about what sort of properties these are: What we should claim is that being red consists in looking red; this is why the equivalence [between looking red and being red] asserted by the dispositional thesis about red holds. . . . The force of the ‘consists in’ claim might be put by saying that, whereas an object looks square because it is square, an object is red because it looks red. (McGinn 1983, 6) As McGinn makes clear, the only sense in which Oxford realists hold that color experiences are able to reveal properties of objects to us, and not merely properties of experience, is in terms of objects being disposed to produce color experiences in us. As the passage above from Descartes’s Principles of Philosophy should remind us, however, this is something that Descartes (and all other Cartesian anti-realists) also hold. Thus, this is yet another point of substantive agreement between Cartesian anti-realism and Oxford realism, not a point of substantive disagreement. In sum: the problem with Oxford realism is that the argument for it is self-undermining. It aims to show that color experiences cannot be guilty of widespread and systematic representational error. But, in its effort to do so, it collapses the target/content distinction. This has the consequence of making it impossible for Oxford realists to make sense of how color experiences might accurately (or inaccurately) represent anything at all. 5.4

THE WAY OUT OF DESCARTES’S QUANDARY The moral of the story is that what we take ourselves to be thinking about are the targets of our representations, not their contents. —Robert Cummins, Representations, Targets, and Attitudes (1996)17

In this section, I explain how the target/content distinction allows us to escape from Descartes’s Quandary. It does so by revealing how this quandary rests upon overlooking an ambiguity in the question, “What do color experiences represent?” Recall the structure of Descartes’s Quandary. It is structured around trying to hold on to the following two thoughts at the same time: (i) Color experiences make us aware of properties of external objects. (ii) Color experiences do not, in themselves, inform us of their external causes. The most important thing to remember about this quandary is that Descartes finds it perplexing—as evidenced by his tendency to vacillate between

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different positions on the nature of color—even though he takes himself to have arrived at a theoretically informed account of the external causes of color experiences (based on his theory of the rainbow), in terms of a specific sort of physical property of light (specifically, the ratio of rotational to forward movement of light particles).18 In response to this quandary, Descartes recoils from holding that what we see when we see colors are these physical properties of light. In this respect, he is far from alone, either in his own time or more recently. Here is G. E. Moore, writing over two and a half centuries later: Consider yellow, for example. We may try to define it, by describing its physical equivalent; we may state what kind of light-vibrations must stimulate the normal eye, in order that we may perceive it. But a moment’s reflection is sufficient to shew that those light-vibrations are not themselves what we mean by yellow. They are not what we perceive. (Moore 1903/1993, 62 [emphasis in original]) And here is Robert Pasnau, more recently: Color . . . just is that familiar quality that we detect through the sense of sight. If we stop talking about that, then we stop talking about color. (Pasnau 2011, 516) Descartes’s, Moore’s, and Pasnau’s recoil is motivated by a shared worry. The worry is that revising the way we think about color to include a theoretically informed account of the external causes of color experience would be changing the subject. We would no longer be talking about color. Here is how McGinn expresses this worry: [The a]scription [of secondary qualities such as colors] cannot be revised as a result of scientific theory or superior perceptual sensitivity because what it is to have them is just a matter of how things seem from a particular point of view. (McGinn 1983, 124) The worry shared by all of these thinkers is that any revisions to how we think about color that take into account the discovery that color experiences are produced by the transduction of light by the retina (or other theoretically informed discoveries about the external causes of color experiences) are bound to lead us to abandon thinking about color at all. The target/content distinction allows us to see that this worry is baseless. If we explicitly introduce the target/content distinction to this situation, we can see that the question, “What do color experiences represent?” is ambiguous between asking about either the targets or the contents of these experiences. These are two distinct ways in which color experiences are semantically related to the world. Accordingly, any adequate theory of how

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color experiences are semantically related to the world must explain how the targets and contents of these experiences are determined independently of one another. I am not here going to take a stand on what, exactly, such an explanation might look like.19 For our purposes, it suffices to note two points that follow merely from the observation that any adequate theory of representation must explain how targets and contents are determined independently of one another. The first point is that the targets of color experiences can remain constant across changes in their contents. To see this, consider how a particular experience of seeing something as red can have the same target regardless of whether the content of this experience is any of the following: Content #1: looking a certain way Content #2: having a certain mixture of the four elements (earth, air, fire, and water) Content #3: having a certain ratio of rotational to forward movement Content #4: having a certain surface spectral reflectance profile The important thing to recognize is that shifting from one of these contents to another does not suffice to imply that one has “changed the subject” of this experience. The target of this experience can perfectly well stay the same across this shift in contents. The worry that any revision to our concept of color must “change the subject” is based on the assumption that the content of an experience exhausts its semantic relationship to the world. But, as the target/content distinction reminds us, that assumption is simply a mistake. The second point is that these multiple contents are not, in and of themselves, mutually exclusive. To see this, notice that the mere fact that these contents are different does not suffice to imply that they conflict. Content #1, for instance, is compatible with either #2, #3, or #4. The primary reason we should be inclined to accept #1 and #4, and reject #2 and #3, is simply that #1 and #4 are accurate, and #2 and #3 are inaccurate. In sum: keeping the target/content distinction clearly in view allows us to escape from Descartes’s Quandary. It does so by revealing how the question “What do color experiences represent?” is ambiguous between asking about the targets and contents of color experiences. The targets of color experiences can perfectly well stay the same across changes in their contents.

5.5 CONCLUSION: AGAINST AHISTORICAL CONCEPTUAL ANALYSIS Family failing of philosophers.—All philosophers have the common failing of starting out from man as he is now and thinking they can reach their goal through an analysis of him. They invariably think of ‘man’ as an aeterna veritas, as something that remains constant

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in the midst of all flux, as a sure measure of things. Everything the philosopher has declared about man is, however, at bottom no more than a testimony as to the man of a very limited period of time. Lack of historical sense is the family failing of all philosophers; many, without being aware of it, even take the most recent manifestation of man, such as has arisen under the impress of certain religions, even certain political events, as the fixed form from which one has to start out. They will not learn that man has become, that the faculty of cognition has become. —Friedrich Nietzsche, Human, All Too Human (1878)20

In this section, I conclude by drawing two morals from the preceding case study. We are now well positioned to see how “the age-old practice among philosophers . . . [to] think essentially ahistorically” (Nietzsche 1998, 10) about our concepts runs the risk of producing a distorted picture of these concepts. The first moral concerns the possible forms that conceptual change and revision can take. In Chapter One, I surveyed a large number of examples of ahistorical conceptual analysis, with the goal of bringing out their shared commitment to the univocality assumption, the assumption that how we think about color must involve a single strand of thought running throughout, rather than multiple, intertwined strands of thought. Chapters Two and Three were designed to challenge the univocality assumption, by offering historical and introspective evidence of the presence of multiple, conflicting strands of thought about color. Beyond blinding us to this multiplicity, however, the univocality assumption comes with an additional cost. It also blinds us to a distinction between two different levels at which a concept might be revised or modified over time: either at a wholesale or retail level. Wholesale revision involves the complete, indiscriminate revision or elimination of an entire way of thinking. Retail revision is much more piecemeal, involving the modification of this or that strand of a concept, without implying that the concept itself must be completely overhauled or abandoned. One of the goals of Chapter Three was to distinguish three different aspects of the Cartesian strand’s critique of the Aristotelian strand, so as to resist the tendency to treat the Cartesian critique as a wholesale, indiscriminate rejection of the Aristotelian strand. Distinguishing these different aspects of the Cartesian strand’s critique allows us to see, in other words, how it is possible for our concept of color to be revised at an extremely fine-grained level, at the level of individual fibers within individual strands of thought. Consider, for instance, the statement that “color is the proper object of vision.” With regard to this statement, Aristotle and Descartes are philosophical false friends, insofar as they both are willing to assert the words “color is the proper object of vision,” while nonetheless assigning completely different meanings to these words. Aristotle takes them to express the idea that vision is defined

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in terms of color, whereas Descartes takes them to express the quite different idea that color is defined in terms of vision. This is a genuine point of tension between the Aristotelian and Cartesian strands, one that an ahistorical approach to conceptual analysis primes us to overlook. But perhaps what is needed to deal with this tension is only a retail-level revision in how we think about color. Revising (or even abandoning) the idea that color is the proper object of vision need not, in itself, entail a wholesale, indiscriminate rejection of our concept of color (or even all of either the Aristotelian or Cartesian strands). Hence my first moral: ahistorical conceptual analysis risks making conceptual revision out to be an all-ornothing affair, whereas it can perfectly well take the form of piecemeal modification and change. The second moral concerns the relationship between our concept of color and our other concepts. By treating our concept of color as part of “a massive central core of human thinking which has no history” (Strawson 1971, 10), ahistorical conceptual analysis promotes and sustains the assumption that this concept is somehow autonomous from whatever else we might discover about the world. Tellingly, both Cartesian anti-realists and Oxford realists make this assumption. The fundamental problem with this assumption, as we have seen in Chapters Two and Three, is that how we think about color is not independent of how we think about the nature of light and its role in the visual process. But if how we think about color depends upon how we think about light and vision, and how we think about light and vision is itself revisable as the result of new discoveries about the world, then the assumption that our concept of color is somehow autonomous starts to look less like an intuitive deliverance of common sense and more like a dogma. The dogma is that there is a fundamental cleavage between concepts that are revisable on the basis of new discoveries about the world, and concepts that are unrevisable because they are somehow autonomous of such discoveries. Hence my second moral: historicized conceptual analysis helps us to overcome an untenable dualism between revisable and unrevisable concepts and thereby better understand the mind’s beholdenness to the world. NOTES 1. Haugeland (1996/1998, 242 [emphasis in original]). 2. Cummins (2010, 112). 3. The target/content distinction is only one of many distinctions that are necessary for thinking about representation. Another is the act/object distinction, the distinction between the act of representing something and the object that does the representing. In what follows, I will generally use the word “representation” as shorthand for the object that does the representing in a particular act of representing something. Whenever it might matter whether I am referring specifically to the act or object of representation, I will explicitly distinguish the two.

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4. In this chapter, I do not endorse any particular theories of target- or contentfixation. My aim is to remain as neutral as possible with regard to how, exactly, one might explain how these are determined. For my purposes, the only point that matters concerns something that can be established prior to having arrived at fully worked-out theories of either target- or content-fixation. 5. Descartes (CSM III 337). 6. “[F]rom the fact that I sense very different colors . . . I rightly infer that there are in the bodies from which these various sensory perceptions come, certain variations corresponding to them, though perhaps not similar to them” (Descartes CSM II 56). 7. “If the speed at which they turn is much smaller than that of their rectilinear motion, the body from which they come appears blue to us; while if they turning speed is much greater than that of their rectilinear motion, the body appears red to us” (Descartes CSM I 323 [emphasis in original]). 8. “[I]f words, which signify nothing except by the institution of men, are sufficient to make us conceive of things which they have no resemblance, why is Nature not able to have also established a certain sign which makes us have the sensation of light, even though this sign has no feature which is similar to that sensation” (Descartes CSM I 81). 9. “For the proper purpose of sensory perceptions given me by nature is simply to inform the mind of what is beneficial or harmful for the composite of which the mind is a part” (Descartes CSM II 58). 10. MacKenzie (1989, 1990, and 1994) and Keating (1999 and 2001) read Descartes as holding (what they call) a non-representationalist view of color experiences, but they do not distinguish between the targets and contents of representations and appear to conflate representational failure and misrepresentation. For an independent criticism of their reading on textual grounds, see De Rosa (2007). 11. Notable discussions of Descartes’s idea of “material falsity” include Kenny (1968), Cottingham (1976 and 1990), Wilson (1978 and 1999), Arbini (1983), Gueroult (1984), Wells (1984), Pariente (1985), Bolton (1986), Normore (1986), Nadler 1989, MacKenzie (1989, 1990, and 1994), Buroker (1991), Beyssade (1992), Schmaltz (1992 and 1997), Field (1993), Alanen (1994), Menn (1995), Hoffman (1996), Nelson (1996), Vinci (1998), Wells (1998), Garcia (1999), Keating (1999 and 2001), Simmons (1999 and 2003), Kaufman (2000), Secada (2000), De Rosa (2004, 2009, 2010, and 2013), Schumacher (2004), Scholl (2005), Smith (2005), Bailey (2006), Brown (2006, 2007, 2008, and 2011), Wee (2006), Clemenson (2007), Behan (2008), Pessin (2009), Naaman-Zauderer (2010), Hwang (2011), Nolan (2011), Shapiro (2012), and Hatfield (2013). 12. The claim that Descartes’s idea of material falsity is confusing goes back to Antoine Arnauld’s “Letter to a Distinguished Gentleman” (i.e., the Fourth Set of Objections to Descartes’s Meditations). As Arnauld puts it: “[W]hen the distinguished gentleman asserted that falsity properly so-called can be found only in judgments, he nevertheless admits a bit later that ideas can be false— not formally false mind you, but materially false. This seems to me to be out of keeping with his first principles” (in Descartes 2006, 122). For other examples of claims that Descartes’s idea of material falsity is confusing, see Kenny (1968, 118–121 and 245–246), Cottingham (1976, 67), McRae (1979, 218), Field (1993, 309), Hoffman (1996, 369), Ayers (1998, 1100 fn. 39), and Shapiro (2012, 379). 13. For example, some have proposed that the material falsity of color experiences is the product of false judgments made in childhood, judgments that mistakenly conflate the opacity of thoughts about color with the clarity of thoughts

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about things like shape (MacKenzie 1989, Alanen 1994 and 2003, Keating 1999 and 2001). Another proposal is that these mistaken judgments are then reinforced by the influence of Scholastic Aristotelianism (Nelson 1996). Others have proposed that materially false ideas are only contingently false, that they can become true if they are informed by a proper scientific understanding of what they are about (Bolton 1986, Brown 2007). Others have proposed that materially false ideas arise from conflating the means by which thoughts about shape are able to represent their objects (in virtue of resemblance) with the means by which thoughts about color are able to represent their objects (in virtue of being natural signs or indications) (Cottingham 1990, Pessin 2009, De Rosa 2010). Others have proposed that materially false ideas are caused by distortions inherent in our sensory representational schema itself (Field 1993, Smith 2005). Others have proposed that materially false ideas are false because they represent we-know-not-what (Nadler 1989, Secada 2000, Nolan 2011). Others have proposed that color experiences are materially false because they represent color as an independently existing substance rather than as a sensory dependent mode (Bolton 1986, Menn 1995, Garcia 1999). Others have proposed that materially false ideas are not representational at all but we mistakenly take them to be so (Normore 1986). Another proposal is that materially false ideas are not representational but only representationlike and, as such, do not represent anything about the world but merely point towards things in it (Beyssade 1992). Another proposal is that materially false ideas are so confused we do not know whether they represent or not (Wells 1984). One more proposal is that materially false ideas arise from conflating the aspects of sensory states that are relevant for self-preservation with the aspects of sensory states that are relevant for representing how the world is (Simmons 1999). 14. Some readers have claimed to find such a distinction in Descartes. See, for example, Pariente (1985), Wilson (1999), Nelson (1996), Smith (2005), and Wee (2006). However, there is no explicit textual evidence for such a distinction in Descartes, as the advocates of this reading themselves acknowledge. As Margaret Wilson, one of the primary advocates of this reading of Descartes puts it, in order to find such a distinction in Descartes “[o]ne must . . . be prepared to be very flexible in interpreting his words” (Wilson 1999, 73) and to hold that “he has merely expressed himself ineptly” (Wilson 1999, 75). Moreover, Wilson herself draws attention to passages in which Descartes seems committed to denying that the targets and contents of representations can be independently determined; as she herself summarizes one such passage, it suggests that “an idea’s referentially representing [i.e., having the target] a does depend on the idea’s somehow presentationally exhibiting [i.e., having the content] a” (Wilson 1999, 82 [emphasis in original]). In other words, Wilson herself admits that there are no passages in which Descartes explicitly introduces a target/content distinction, and that there are passages in which it seems that he explicitly collapses this distinction. 15. McDowell (1998, 357). 16. These three features are all present in the follow passage from Descartes’s Principles of Philosophy: “It is clear, then, that when we say that we perceive colors in objects, this is really just the same as saying that [1] we perceive something in objects such that we do not know what it is, but which produces in us a certain very manifest and vivid sensation which is called the sensation of color. But . . . as long as we merely judge that there is something in objects (that is, in the things, of whatever kind exactly they may be, from which our sensations come to us) such that we do not know what it is, then we avoid error; indeed, we are actually guarding against error, since the recognition that

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17. 18.

19.

20.

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we are ignorant of something makes us less liable to make any rash judgement about it. But [2] it is quite different when we suppose that we perceive colors in objects. Of course, we do not really know what it is that we are thus calling by this name “color,” and we cannot understand any resemblance between the color that we suppose to be in objects and that which we experience in sensation. But because we do not notice this very fact, and because there are many other things, such as size, shape, number, etc., that we clearly perceive to be sensed or understood by us in a way that is not different from the way they are or at least could be in objects, [3] we easily fall into the error of judging that what we call color in objects is entirely similar to the color which we sense, and thus of supposing that we clearly perceive what we in no way perceive” (CSM I 218). Cummins (1996, 121). For our purposes, the differences between Descartes’s account of the external causes of color experiences and a more contemporary account (such as Nassau [2001]) do not matter, because neither Descartes’s nor Nassau’s account is available to us just in virtue of having color experiences. Two candidates for how the targets of color experiences might be determined are (i) in terms of the biological function of the visual system, or (ii) in terms of the information that the visual system makes available to us about the external world. For discussion of these candidates, see Cummins (1996, Chap. 8). Nietzsche (1878/1996, 12–13).

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Index

academic cottage industries 40–1 fn. 4, 78 fn. 28, 92, 105 fn. 26, 105–6 fn. 27, 133–4 fn. 13 ahistorical conceptual analysis xv–xviii, 130–2 Allen, K. 10 analogy between color and pain 7, 98–101 arbitrariness of relationship between color experiences and their causes 63–4, 66–9 Aristotelian distinction between true and apparent colors 34–7, 43 fn. 23, 43 fn. 25, 52–7, 73–4, 77 fn. 20 Aristotle: on color 28–37; on light 30–1; on vision 27–8 Averill, A. 19–21 Boyle, R. 50, 52, 57, 66, 91, 96, 98–9 Broackes, J. 11 Cartesian anti-realism 2–3, 116–22 Clark, M. xv, 18 cognitive penetrability xvii–xviii Cohen, J. 13–15, 16–17 color: Aristotle’s theory of 28–37; Descartes’s theory of 52–69, 86–103, 116–122; and geometry 87, 103 fn. 6; and ordinary speech 94–5; as the proper object of vision 28–32, 64–6, 72, 131–2 contingency of relationship between color experiences and their causes see arbitrariness of relationship between color experiences and their causes Cummins, R. 112–15

Descartes, R. on color 52–69, 86–103, 116–22; on light 50–2, 57; on vision 50–2, 58–9 Descartes’s Quandary 92–5, 128–30 descriptive metaphysics xvi, 6, 130–2 dispositionalism 3–9, 95–103, 122–8 doctrine of species 32–3, 58–64 doctrine of specific nerve energies 65–6; see also arbitrariness of relationship between color experiences and their causes Dominis, M. 36–7 experimental evidence of intuitions about color 13–18 Eustachius 28, 32, 36, 42 fn. 17 Evans, G. 6–9, 101, 123–4 final dogma of empiricism 132 first-order/second-order color claims xviii genealogical method xv–xviii, 130–2 Hacking, I. 102 Harman, G. 9–10 Hilbert, D. 19–21, 98 Hyman, J. 4, 22 fn. 10, 72 internalism 93–5, 119–122 intrinsic view of color 9–13 introspective evidence of intuitions about color 19–21, 38–9, 70–2 Johnston, M. 12–3, 39–40, 72 Kepler, J. 51–2, 57, 75 fn. 8

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light: 12, 19–21, 36–7; 38–40, 69–72; Aristotle’s theory of 30–1; Descartes’s theory of 50–2, 57; transduction of by retina 61–2, 68–9 Locke, J. 91, 96–7, 98–9 Mackie, J.L. 2–3 McDowell, J. 4, 5–6, 124–5 McGinn, C. 125–8, 129 material falsity (or materially false ideas) 117–120, 133–4 fn. 13 Maund, B. 2–3, 121–2 misrepresentation 114–16 Nietzsche, F. xv–xviii, 130–2 Oxford realism 3–9, 122–8 Philoponus 43 fn. 27 philosophical false friends 101–2, 131–2 Posidonius 34, 43 fn. 24 primary/secondary quality distinction 66–9, 73–4 problem of color realism 1–9, 73–4, 112–28 rainbow: Aristotle’s theory of 34–7; Descartes’s theory of 53–7 representational failure/misrepresentation distinction 114–15 resemblance theory of perceptual representation 33, 59–64; see also doctrine of species

Roberts, P. 15–18 Rubio, A. 37, 42 fn. 17 steady/unsteady colors 12–13, 39–40; see also Aristotelian distinction between true and apparent colors Stout, G.F. 11–12 Strawson, P.F. xv–xvi, 5–6, 72, 130–2 Suárez, F. 34 target/content distinction 112–16, 120–2, 127, 129–30 transduction of light by retina 61–2, 68–9 true/apparent distinction see Aristotelian distinction between true and apparent colors and primary/secondary quality distinction univocality assumption 1, 3, 8–9, 17–18, 20–1, 130–2 vacillation: in Boyle 105 fn. 26; in Descartes 90–2, 94–5, 104 fn. 11; in dispositionalism 95–7; in Evans 124; in intuitions about color 19–21, 73–4; in Locke 105–6 fn. 27; in McDowell 124–5 vision: Aristotle’s theory of 27–8; Descartes’s theory of 50–2, 58–9; intromissionist and extramissionist theories of 44 fn. 28 Wolf-Devine, C. 88–90