Elements of Christian Philosophy

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Elements of Christian Philosophy

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Elements of Christian Philosophy

ETIENNE GILSON Member of the Pontifical Academy of Saint Thomas Aquinas Rome Director of Studies in the Pontifical Institute of Mediaeval Studies Toronto

DOUBLEDAY & COMPANY, INC. Garden City, New York

Nihil obstat: Armand Maurer, C.S.B., Censor Deputatus Imprimatur:

James C. Cardinal McGuigan, D.D., Archbishop of Tor onto

Date: 14 November 1959 A cknonxle dgmen ts: The author wishes to thank the following publishers for permission to use materials under their copyright: Doubleday & Company, Inc., for permission to quote from St. Thomas’ On the Truth of the Catholic Faith, Book I, tr. A. C. Pegis, and Book II, tr. J. F. Anderson (Garden City, N.Y.: Doubleday & Company, Inc., 1955 and 1956); B. Herder Book Co., for permission to quote St. Thomas’ Compendium of The¬ ology, tr. C. Vollert, S.J. (St. Louis: B. Herder Book Co., 1947); Random House, Inc., for permission to quote many passages from Basic Writings of Saint Thomas Aquinas and Introduction to Saint Thomas Aquinas, tr. A. C. Pegis, (New York: Random House, Inc., 1944 and 1948).

All Rights Reserved Copyright (C) i960 by Doubleday & Company, Inc. Printed in the United States of America Designed by Faith Nelson



The words “Christian philosophy” do not belong to the language of St. Thomas Aquinas, but they are the name under which, in his En¬ cyclical Letter Aeterni Patris, Pope Leo XIII designated the doctrine of the Common Doctor of the Church in 1879. Such as it is described in this epoch-making document, Christian philosophy is that way of phi¬ losophizing in which the Christian faith and the human intellect join forces in a common investigation of philosophical truth. The study and the teaching of Christian philosophy are both beset with many difficulties. Lirst of all, in the form it has been given by St. Thomas, it presupposes for its understanding an elementary knowl¬ edge of the philosophy of Aristotle. The study of the Philosopher takes time, and when the moment comes for the student to tackle the doctrine of Thomas himself he still needs to be trained in the art of uniting the light of faith and the light of the intellect. As often as not, he has been warned to be careful about keeping his faith out of philo¬ sophical research in order to preserve whole and entire its rational purity. It is then too late for any student to adopt a new approach to St. Thomas, and it is to be feared that the very nature of Thomism will remain thereafter unknown to him. Another difficulty arises from the theological method followed by St. Thomas in those very works in which his own philosophical views are found in their purity, namely, the two Summae and the long series of his Disputed Questions. As a theologian, Thomas felt perfectly free to draw arguments from many and diverse philosophies and to confirm his conclusions by means of all sorts of reasons whose very multiplicity is liable to embarrass beginners. This complex situation is the problem to which the present book seeks to bring, if not a solution, at least a working introduction. Its author’s experience suggests that students often fail to find their way in the teaching of the Common Doctor for lack of a proper mastery of fundamental principles or elements. We call here “elements” those key notions and doctrinal positions that are not always explicitly stated in the discussion of each particular problem, but whose knowledge is re¬ quired for a complete understanding of St. Thomas’ answers. Such are:


Foreword, first and foremost, the specific nature of the way in which the theolo¬ gian uses philosophy according to the view of St. Thomas; second, the Thomistic notion of being, including the consequences it entails for the doctrine of the transcendental; last, not least, the impact of this same notion on the many philosophical problems in whose data it is included —God, substance, efficient causality, creation, the structure of finite being, the nature and unity of man, the soul, the human intellect and its object. These and other key notions are so many basic doctrines that need to be correctly understood before the student attempts to face the colossal array of particular questions and answers, objections and re¬ plies, that make up the body of the Christian philosophy of St. Thomas Aquinas. The detailed study of St. Thomas really has no end, but this fact is one of the charms of a life spent in the company of the Common Doctor of the Church. Something new is always there to be learned from him. The real danger is that the student may spend years pondering St. Thomas’ doctrine without realizing that he has not yet even begun to grasp its meaning. This is bound to happen every time the student misses the only true gateway there is to the proper understanding of Thomism, namely, a certain metaphysical notion of being tied up with a certain notion of the Christian God. To describe these two notions, and to show them at work in a small number of capital problems, such has been our main concern in writing the present book. Elements of Christian Philosophy does not pretend to replace any other book. We would rather like to think that it will help to confer upon other interpre¬ tations of St. Thomas the fullness of their own religious meaning.







Chapter i. The teacher of Christian truth Chapter 2. Sacred doctrine PART II: GOD




Chapter 3. The existence of God


I. The existence of God is not self-evident II. The existence of God is demonstrable

44 48

hi. Demonstrations of the existence of God A. The way of motion



a. The language of the proof


b. The meaning of the proof


c. Interpretation of the first way


b. The way of efficient causality


c. The way of possibility and necessity d. The way of the degrees of perfection e. The way of purposiveness

72 74


F. The meaning of the five ways


Chapter 4. Metaphysical approaches to the knowledge of God I. Materialistic scientism


II. The Cause of substantial mutations hi. The Cause of being


a. Being and unity


b. Being and perfection

c. Being and existence Chapter 5. The essence of God



pp 101


I. Whether the human mind can arrive at the knowledge of God? II. The simplicity of God hi. HE WHO IS

104 m


iv. Reflections on the notion of being





Chapter 6. God and the transcendental 133 I. The problem of the divine names II. Being and unity



in. Being and the true


iv. Being and the good


v. The forgotten transcendental: Pidchrum Chapter 7. Being and creation


Chapter 8. Being and causality




Chapter 10. Man and knowledge Chapter 11. Man and will NOTES TO THE TEXT



Chapter 12. Man and society

261 281


Chapter 1. The teacher of Christian truth Chapter 2. Sacred doctrine PART II



Chapter 9. The human soul






Chapter 3. The existence of God


Chapter 4. Metaphysical approaches to the knowledge of God Chapter 9. The essence of God 303 PART III


Chapter 6. God and the transcendentals Chapter 7. Being and creation


Chapter 8. Being and causality




Chapter 9. The human soul


Chapter 10. Man and knowledge Chapter 11. Man and will Chapter 12. Man and society BIBLIOGRAPHY













Chapter i. The teacher of Christian truth The nature and significance of the work done by Saint Thomas Aquinas cannot be fully understood by those who approach it as if there had been nothing before it.1 When he himself began to teach theology and, later on, philosophy (as he was to do in his commentaries on Aristotle), Thomas Aquinas was well aware of the general context in which his own work was necessarily going to be done. Up to the last years of the twelfth century, when the Christian world unexpectedly discovered the existence of non-Christian interpretations of the universe, Christian theology had never had to concern itself with the fact that a non-Christian interpretation of the world as a whole, including man and his destiny, was still an open possibility. When Thomas Aquinas began to develop his own doctrine—that is to say, about 1253-54—Christianity had already discovered Greek philosophy. The discovery owed nothing to Thomas Aquinas himself. To be sure, his later commentaries on Aristotle were to be major contributions to a better interpretation of the teaching of the Philosopher; but anyone pretending that he was discovering the world of the Greek philosophers about 1250 would simply have been at least fifty years late. By that time, every Christian university teacher knew that a non-Christian ex¬ planation of the world was possible; he even knew what that explana¬ tion was, at least in its broad outline. But the question of the proper attitude to adopt toward it was very complex, and every teacher had to evolve his own answer. To a man of the thirteenth century in western Europe, what did the term “philosopher” mean? Among other things, it meant a pagan. A philosopher was a man who, born before Christ, could not have been informed of the truth of Christian Revelation. Such was the situation of Plato and Aristotle. The Philosopher par excellence was a pagan. Others, born after Christ, were infidels. Such was the situation of Alfarabi, Avicenna, Gabirol, and Averroes. Whatever the case, it can be said that


Revelation and the Christian teacher in general one of the connotations of “philosopher” was a “pagan” philosopher. Of course there is nothing absolute in the use of words, and exceptions can always be found. For instance, Boethius has some¬ times been called a “philosopher” and counted as one. But this use of the word is exceptional, and countless cases can be quoted in which the pagan connotation of the word “philosopher” is certain.2 Here, however, we should be careful to observe that this was a ques¬ tion of usage, not of definition. In describing philosophia, no thirteenthcentury theologian would have said that, in essence, philosophy was pagan. Had he been asked to define a philosopher, the same theologian would probably not have said that, unless he was a pagan, a man could not be a philosopher. The point I am emphasizing is that, as a matter of fact, when a theologian said “the philosophers” or “a philosopher,” what he normally had in mind was a man who, not being a Christian, had dedicated his life to the study of philosophy. The general truth of this remark is confirmed by the frequent antithetical use made by thirteenth-century theologians of the words philosophi and sancti. Albert the Great does not hesitate to quote two different series of definitions of the soul: those by the sancti and those by the philosophi. “A philosopher,” in other words, was not a “saint”; that is, he was not a man sanctified by the grace of baptism. If a theo¬ logian thought it proper to resort to philosophy in his own theological work, as was the case with Thomas Aquinas, he was not normally called a philosopher, but rather a philosophans theologus (a philosophizing theologian) or, more simply still, a philosophans (a philosophizer). This was not a strict rule. But judging from their customary use of the two words, it does not seem to have entered the minds of thirteenthcentury theologians that one and the same man could be, at one and the same time, both a “philosopher” and a “saint”.3 One of the consequences of this all-embracing classification was that in its concrete reality philosophy appeared to many a theologian as an undifferentiated mass of doctrines containing the teachings of almost all those who, being unacquainted with Christian truth, or not accepting it, had tried to achieve a consistent view of the world and of man by means of reason alone. This philosophical conglomerate is well rep¬ resented by the encyclopedia of Albert the Great, in which elements borrowed from all available sources are blended together and reduced to a sort of loose unity. If we knew them better than we do, such encyclopedias as the unpublished Sapientale of Thomas of York would give us a still more impressive view of what the word philosophia meant 12

The teacher of Christian truth to the mind of a thirteenth-century theologian. Aristotle is there, es¬ pecially


his Averroistic


but so



Gundissalinus, Gabirol, Cicero, Macrobius, Hermes Trismegistus: in short, the whole philosophical literature available at the time is rep¬ resented in it. Here special mention should be made of the influence exercised by the masters in arts in the first European universities. Having to teach the doctrine of Aristotle, they first had to ascertain the exact meaning of his writings. In so doing, they naturally had to discount Christian faith and theology, but they also had to separate the teaching of Aristotle from the foreign elements which his translators and interpreters had blended with it. It is a revealing fact that, in his Commentary on the Sentences of Peter Lombard, Thomas Aquinas still considered the Liber de Causis an authentic work of Aristotle. This was much more than a mere case of false attribution. In order to attribute the Plotinian Liber de Causis to Aristotle, one must have an extremely vague notion of the overall meaning of Aristotle’s metaphysics. During the years he spent in Italy, from 1259 to 1268, Thomas Aquinas found at his disposal new translations of the writings of Aristotle, or revisions of older translations, made by William of Moerbeke, and he availed himself of this opportunity to write com¬ mentaries on the nature of Aristotle’s doctrine. It is difficult to charac¬ terize in a few words the new Aristotle seen by Thomas Aquinas. Some of the features at least are easily visible. Strictly speaking, it is not cor¬ rect to say that Thomas baptized Aristotle. On the contrary, every¬ where that Aristotle either contradicts the truth of Christianity (the eternity of the world) or simply falls short of it (creation ex nihilo), Thomas either frankly says so or at least does not attribute to Aristotle what he did not expressly assert. For instance, it is remarkable that, in commenting on the Metaphysics of Aristotle, in which the causality of the Prime Mover plays such an important part, Thomas Aquinas does not once use the word creatio. Neither does he attempt to prove the immortality of the soul in his Commentary on the De Anima. Aristotle had not presented the whole philosophical truth, and Thomas was well aware of the fact, but he did not try to make him say it. On the other hand, Thomas Aquinas has clearly seen that, in the writings of Aristotle as we now have them, a certain number of points are incompletely determined, and he saw no reason why, in such cases, an interpretation of the doctrine attributed to the Philosopher should necessarily be preferred on the ground that it was the least easy of all


Revelation and the Christian teacher to reconcile with the teaching of Christian faith. For instance, on the problem of the agent intellect, there was in Averroes a noticeable hard¬ ening of the position of Aristotle; but Thomas did not consider it useful to render Aristotelianism as more brutally opposed to Christian truth than it actually was in the authentic teaching of Aristotle himself. In short, it can be said that Thomas has removed from Aristotle all the obstacles to Christian faith that were not evidently there. At any rate, if he has baptized Aristotle, Thomas did not do so in his commentaries, but rather in his own theological writings. When he did so, baptism produced its normal effect: the vetus homo first had to die so that a new man could be born. The name of this new Christian had to be a Christian name: not Aristotle, but Thomas. After thus removing the unnecessary obstacles, Thomas Aquinas found himself in a rather different position from that of the other theo¬ logians. There was nothing fundamentally wrong with this purified Aristotle; his only shortcoming was that, on certain points, he had simply failed to see certain truths, and this failure could be remedied by completing his doctrine. The real difficulty was that, in order to com¬ plete Aristotle, one had first to modify certain basic notions in philoso¬ phy and, thereby, to submit the philosophy of Aristotle to far-reaching modifications. Even purified of gross errors, Aristotelian doctrine still could not provide Thomas Aquinas with a ready-made philosophy; but he seems to have seen it as the very summit of philosophical speculation. Aristotle really was for Thomas the Philosopher par excellence: that is, a witness of the very best that the natural reason of man can do when it investigates truth without the help of divine revelation. From this point of view, Aristotle appeared to Thomas Aquinas as having stated, not the whole truth accessible to human reason, but at least the whole philosophical truth. Thanks to the accomplishment of Aristotle, Thomas knew how far philosophy could proceed on the way to complete truth. By the same token, Thomas had gained a clear notion of what it meant to philosophize, and this knowledge deprived him of the simple answers to which, before him, theologians had often resorted. Afore precisely, 1 homas could not content himself with adopting, in any particular case, the kind of philosophy that was easiest to reconcile with Christianity. For instance, he could not borrow his definition of the human soul from Aristotle and at the same time borrow from Plato his demonstrations of the immortality of the soul. What is most im¬ portant to realize in approaching the works of Saint Thomas Aquinas is that piecisely because he had now understood what a philosophical

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