A Brief History of the Soul E-Book

Stewart Goetz

• Herausgeber: John Wiley & Sons
• Kategorie: Geisteswissenschaft
• Sprache: Englisch

Seitenzahl: 405

Veröffentlichungsjahr: 2011

Beschreibung

This book is a clear and concise history of the soul in western philosophy, from Plato to cutting-edge contemporary work in philosophy of mind. * Packed with arguments for and against a range of different, historically significant philosophies of the soul * Addresses the essential issues, including mind-body interaction, the causal closure of the physical world, and the philosophical implications of the brain sciences for the soul's existence * Includes coverage of theories from key figures, such as Plato, Aquinas, Locke, Hume, and Descartes * Unique in combining the history of ideas and the development of a powerful case for a non-reductionist, non-materialist account of the soul

Leseprobe

Contents

Cover

Half Title page

About the Authors

Brief Histories of Philosophy

Title page

Copyright page

Dedication

Acknowledgments

Introduction

Chapter 1: The Soul in Greek Thought

Plato

Aristotle

Chapter 2: The Soul in Medieval Christian Thought

Augustine

Aquinas

Chapter 3: The Soul in Continental Thought

Descartes

Malebranche and Leibniz

Chapter 4: The Soul in Locke, Butler, Reid, Hume, and Kant

Locke

Butler

Reid

Hume

Kant

Chapter 5: The Problem of Soul—Body Causal Interaction

Causation and Dualism

Why Not Locate Souls in Space?

Property/Event Dualism or Dual Aspect Theory

Chapter 6: The Soul and Contemporary Science

The Soul and the Brain

The Soul and Scientific Methodology

Soul–Body Causal Interaction and the Conservation of Energy

Chapter 7: Contemporary Challenges to the Soul

The Ghost in the Machine Objection

The Private Language Argument

Ockham’s Razor and Identity

Argument from Neural Dependence

Arguments from Personal Identity

Argument from Evolution

Chapter 8: Thoughts on the Future of the Soul

Naturalism versus Theism

The Physical World

Cross-Cultured Inquiry

Value Inquiry

Bibliography

Index

A BRIEF HISTORY OF THE SOUL

Stewart Goetz is Ross Frederick Wicks Distinguished Professor in Philosophy and Religion at Ursinus College. He has written extensively on the philosophy of mind and action theory and his books include Freedom, Teleology, and Evil (2008), Naturalism (with Charles Taliaferro, 2008), and The Soul Hypothesis (edited with Mark Baker, 2011).

Charles Taliaferro is Professor of Philosophy at St. Olaf College. He is on the editorial board of the American Philosophical Quarterly, Religious Studies, Sophia, and Philosophy Compass. His books include Consciousness and the Mind of God (1994, 2004), Naturalism (with Stewart Goetz, 2008), A Companion to Philosophy of Religion, 2nd edition (edited with Paul Draper, Wiley-Blackwell, 2010), and The Image in Mind (with Jil Evans, 2010).

Brief Histories of Philosophy

Brief Histories of Philosophy provide both academic and general readers with short, engaging narratives for those concepts that have had a profound effect on philosophical development and human understanding. The word “history” is thus meant in its broadest cultural and social sense. Moreover, although the books are meant to provide a rich sense of historical context, they are also grounded in contemporary issues, as contemporary concern with the subject at hand is what will draw most readers. These books are not merely a tour through the history of ideas, but essays of real intellectual range by scholars of vision and distinction.

Already Published

A Brief History of Happiness by Nicholas P. White

A Brief History of Liberty by David Schmidtz and Jason Brennan

A Brief History of the Soul by Stewart Goetz and Charles Taliaferro

Forthcoming

A Brief History of Justice by David Johnston

This edition first published 2011© 2011 Stewart Goetz and Charles Taliaferro

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Library of Congress Cataloging-in-Publication DataGoetz, Stewart.A brief history of the soul / Stewart Goetz and Charles Taliaferro.p. cm.—(Brief histories of philosophy)Includes bibliographical references and index.ISBN 978-1-4051-9633-8 (hardcover : alk. paper)—ISBN 978-1-4051-9632-1(pbk. : alk. paper) 1. Soul. I. Taliaferro, Charles. II. Title.BD421.G64 2011128′.109—dc22

2010043497

A catalogue record for this book is available from the British Library.

This book is published in the following electronic formats: ePDFs 9781444395914; Wiley Online Library 9781444395938; ePub 9781444395921

We dedicate this book to Roderick Chisholm, author, teacher, and mentor, and to John Strassburger, friend, colleague, and president emeritus of Ursinus College

Acknowledgments

We thank Nick Bellorini for inviting us to undertake this project, and Jeff Dean, Tiffany Mok, and Ben Thatcher of Wiley-Blackwell for their kind and generous support. We owe a special debt of gratitude to Manuela Tecusan for absolutely first-rate copy-editing advice. We are also deeply grateful to the John Templeton Foundation for providing financial assistance that supported our work on the book. Finally, we thank Tess Cotter for assistance in preparing the manuscript and Michael DelloBuono for compiling the bibliography.

Introduction

The current intellectual climate is quite hostile to the idea that we are embodied souls. The idea that there might be more to us than our physical bodies is out of step with contemporary secular philosophy. There is a prevailing assumption that we human beings and other animals are thoroughly physical–chemical realities. To be sure, physio-chemical organisms like us have extraordinary powers and capacities (powers to think and choose, and capacities to feel pleasure and pain), but most philosophers today think this does not make us in any way non-physical or entail that there is more to us than physio-chemical processes. Daniel Dennett offers this summary of the current materialist view of the natural world and the mind:

The prevailing wisdom, variously expressed and argued for, is materialism: there is only one sort of stuff, namely matter—the physical stuff of physics, chemistry, and physiology—and the mind is somehow nothing but a physical phenomenon. In short, the mind is the brain. According to materialists, we can (in principle!) account for every mental phenomenon using the same physical principles, laws and raw materials that suffice to explain radioactivity, continental drift, photosynthesis, reproduction, nutrition, and growth. (Dennett 1991, 33)

From the standpoint of a comprehensive form of materialism, talk about “souls” only makes sense as a metaphor for referring to one’s

values or identity, as for instance in “Jones sold his soul to become a celebrity.” The existence of the soul retains some life in fictional worlds such as J. K. Rowling’s hugely popular Harry Potter books (a soul can be sucked out of a character by the kiss of a dementor) but not in the real world. In Philosophy of Mind, Jaegwon Kim says the following about the soul:

The general idea […] is that because each of us has a soul, we are the kind of conscious, intelligent, and rational creature we are. Strictly speaking, we do not really “have” souls, since we are in an important sense identical with our souls-that is, each of us is a soul. My soul is the thing that I am. Each of us “has a mind,” therefore, because each of us is a mind. All that is probably a bit too speculative, if not totally fantastical, for most of us to swallow. (Kim 2006, 29)

The traditional account of the soul is still mentioned in the average philosophy of mind textbook, but rarely taken seriously. For example, in The Problem of the Soul Owen Flanagan contends that, if we recognize the soul at all, we need to see that it is the very same thing as the brain:

The mind or the soul is the brain. Or better: Consciousness, cognitition, and volition are perfectly natural capacities of fully embodied creatures engaged in complex commerce with the natural and social environments. Humans possess no special capacities, no extra ingredients, that could conceivably do the work of the mind, the soul, or free will as traditionally conceived. (Flanagan 2002, xii)

Is the prevalent materialist outlook beyond challenge? Could there still be a sound case for holding that there is more to being a human (and perhaps an animal, too) than physio-chemical processes?

In this book we explore the history of the idea that we are embodied souls. Many contemporary philosophers who reject the view that we are, or contain, souls yet acknowledge that such a view seems natural, and even a matter of common sense. William Lyons writes that the view “that humans are bodies inhabited and governed in some intimate if mysterious way by minds (or souls) seemed and still seems to be nothing more than good common sense” (Lyons 2001, 9). One way to bring out the apparent common sense of such a stance is to appreciate how we think about death. We often think that, when a person dies, the person either perishes or (if we subscribe to religious traditions) is with God or in some kind of afterlife, heaven or reincarnation. In any case, we often treat a person’s dead body as a corpse (or remains), and not as the same thing as the man himself or the woman herself. Even to allow for the possibility of one’s surviving the death of the body is to court the possibility that one is more than a body. Moreover, it is puzzling to think how it can be that all our sensations, conscious experiences, and so on are the very same thing as brain states. To be sure, there is an evident, clear sense in which our sensations are affected by the brain, and it appears that our bodily processes are affected by our beliefs and desires. But establishing a correlation between the mental and the physical is not the same thing as establishing their identity. Colin McGinn rightly points out the apparent distinction between the mental and the physical:

The property of consciousness itself (or specific conscious states) is not an observable or perceptible property of the brain. You can stare into a living conscious brain, your own or someone else’s, and see there a wide variety of instantiated properties—its shape, colour, texture, etc—but you will not thereby see what the subject is experiencing, the conscious state itself. (McGinn 1991, 10–11)

So, while many contemporary philosophers (including McGinn) deny the traditional belief that we are embodied souls and deny that consciousness is more than brain states, the belief that there is more to us than physical–chemical processes has some initial, commonsense credibility.

As it happens, we actually accept the truth of this apparent commonsense distinction of soul and body. In the philosophy of mind literature, the position we hold would customarily be called substance dualism, though the term “dualism” is so fraught with misunderstanding and meets with such derision that we will only use it sparingly. “Dualism” as a philosophical term is a late invention (so-called dualists, from Plato to Descartes, did not use any equivalent expression in their languages, or any of its cognates). Indeed, ancient Greek does not even have a word for “dualism.” We will, however, pay close attention to all the classical and contemporary objections to “dualism.”

Our aim is to set before you a brief history of the idea that we are embodied souls. We are deeply committed to making this a fair and balanced history, but it will also contain a sustained investigation into what we may gain from this history for our thinking constructively about the soul today. One of our goals in this book is to explain, at least in part, why a history of the soul terminates with an age in which those who are learned deny the very existence of that which is the subject of this book. The arguments of those who deny the soul’s existence are powerful and complex but, we hope to show, unconvincing. Even if we are unsuccessful, we believe that reading a history of the soul written by advocates of the soul will make for a more dramatic and interesting engagement than if the authors were to think that the notion of soul is only of antiquarian interest.

We are convinced that the time is right for a brief history of the soul. While a form of materialism that rejects the soul is the dominant position of the day, not all the materialists are content with the current state of play in their field. A life-long materialist, William Lycan finds himself not persuaded by the philosophical case for dualism; but he is not convinced by the case against it either—nor does he embrace the philosophical case for materialism:

Being a philosopher, of course I would like to think that my stance is rational, held not just instinctively and scientistically and in the mainstream but because the arguments do indeed favor materialism over dualism. But I do not think that, though I used to. My position may be rational, broadly speaking, but not because the arguments favor it: Though the arguments for dualism do (indeed) fail, so do the arguments for materialism. And the standard objections to dualism are not very convincing; if one really manages to be a dualist in the first place, one should not be much impressed by them. (Lycan 2009, 551)

Although Lycan is not persuaded by arguments for dualism, there has been a renaissance of philosophical work on the soul over the past twenty years, which indicates that the case in favor of its existence is better than Lycan estimates. In light of this development, it is timely to consider the arguments for and against different conceptions of the soul (and thus for and against materialism) not just in contemporary philosophy, but also from a comprehensive, historical perspective.

Two final points before we get started: First, we make liberal use of quotations in our brief history, so that the many figures we cover can speak for themselves. We believe that all the main figures we cover have important things to say to us today, and we hope that this history will prompt you to read these fascinating philosophers directly. In a longer history, more of each philosopher would be represented and more philosophers would be part of the story. But here we are aiming to engage both newcomers and seasoned scholars in thinking or re-thinking the history of the soul and its bearing on our own thinking about human nature today.

Second, all subsequent references to the Platonic dialogues and works in the Aristotelian corpus can be consulted in the editions listed in the bibliography. When we wish to specify one translation rather than another for a quoted passage, we add the translator’s name in a bracket.

Chapter 1

The Soul in Greek Thought

In this chapter our focus is on the two best known figures of ancient Greek philosophy: Plato (428/7–348/7 BCE) and Aristotle (384–322 BCE). There are other major philosophers in Greek thought, both before Plato and after Aristotle, and some of them hold a place of honor in the development of great future ideas, such as the hypothesis that the material world is made up of atoms, or the thesis that life evolved; but Plato and Aristotle are the most important ones in shaping the history of the soul.

Plato

Before diving into Plato’s view of the soul, three important points need to be observed. First, because the central figure in Plato’s dialogues is the philosopher Socrates, the question about which views are Socrates’ and which are Plato’s is not easy to answer, if it is answerable at all. For the sake of brevity and clarity of presentation, we will not enter the debate about this matter and we will not distinguish between Socrates’ and Plato’s thought. We will simply assume that Socrates’ philosophical views about the soul are Plato’s.

Second, we stress that Plato’s treatment of the soul is philosophical in nature. It is necessary to emphasize this point because it is not uncommon in certain circles (e.g. theological; see Chapter 2) to find assertions to the effect that Plato invented the idea of the soul and, therefore, that the concept of the soul is a Greek idea. Nothing could be further removed from the truth. Belief in the existence of the soul is, as we pointed out in the Introduction, commonsensical in its nature, in the sense that it is espoused by the ordinary person. What Plato did was to philosophize about the nature of the soul in which ordinary people believe.

Third, the Greek term used in ancient philosophical texts and commonly translated as soul is psyche, a noun derived from the verb psychein, which meant to breathe. For philosophers, psyche came to stand, not for breath, but for the life of a being or for that which generates and constitutes the essential life of a being. The great philosopher and classicist A. E. Taylor offers this overview, in which he points out that psyche can involve (though this meaning is secondary) consciousness—a term that was probably coined in the seventeenth century by Ralph Cudworth, to stand for “awareness”:

Consciousness is a relatively late and highly developed manifestation of the principle which the Greeks call “soul.” That principle shows itself not merely in consciousness but in the whole process of nutrition and growth and the adaptation of motor response to an external stimulation. Thus consciousness is a more secondary feature of the “soul” in Greek philosophy than in most modern thought, which has never ceased to be affected by Descartes’ selection of “thought” as the special characteristic of psychical life. In common language the word psyche is constantly used where we should say “life” rather than “soul,” and in Greek philosophy a work “on the Psyche” means what we should call one on “the principle of life.” (Taylor 1955, 75)

As we shall see in different chapters, the definition of the soul is dynamic, though Plato’s view on the soul or psyche has great historical significance, coming as it does as from the first major contributor to the philosophy of the soul. As an aside, we note that the term “soul” in English today is derived from sawel/sawol in Old English, as found in the Vespasian Psalter and in Beowulf. What, then, did Plato have to say about the soul? His thoughts are many and wide-ranging in scope, and they seem to develop over time in ways that sometimes present problems of consistency. We will focus on those thoughts that comprise the core of his view and, when appropriate, we will point out the tensions among them.

We begin with the end of Socrates’ life. While Socrates is in prison and not long before he drinks the hemlock that will bring about his death, his friend Crito asks him about how he would like to be buried. “Any way you like, replied Socrates, that is, if you can catch me and I don’t slip through your fingers. […] I shall remain with you [Crito and other friends] no longer, but depart to a state of heavenly happiness […] You [the other friends] must give an assurance to Crito for me […] that when I am dead I shall not stay, but depart and be gone” (Plato 1961: Phaedo, 115C–D). From this response of Socrates to Crito’s question it seems reasonable to infer that Plato believes the “person” Socrates is his soul (as opposed to his soul plus his body, or just his body).

Like most philosophers after him up until Descartes in the seventeenth century, Plato claims that the soul is that which imparts life to its body (Phaedo, 105C–D). Moreover, because the soul is that which gives life to its body and cannot acquire a property that is contrary to its essentially life-giving nature, the soul itself can never perish (Phaedo, 105D–E). Plato’s rationale behind this view of properties is tenuous; but, for a start, we simply note that he thought of the soul as essentially and fundamentally alive, whereas he did not think this was the case with the body. The soul is indestructible or imperishable, and thereby the soul is unlike its body and other material things, which by nature are always changing and never keep to the self-same condition (Phaedo, 79C). When a person dies, the body may perish but the soul endures. Plato argues that, because change is always from contraries (e.g., that which becomes bigger does so from that which is smaller, and that which is darker comes from that which is lighter), the soul must have come from the realm of the dead and return there after completing its life in this world, only to return once again to the realm of the living (Phaedo, 70C–72E). While belief in reincarnation may strike western secular readers as preposterous, it is interesting to take note not only of the presence of a belief in reincarnation in the ancient west (one of the best known Presocratic philosophers, Pythagoras, taught reincarnation, and reincarnation is in evidence in one of the greatest Roman epic poems, Virgil’s Aeneid, Book VI), but also of its widespread adherents today, among Hindus and Buddhists. In any case, given the way Plato describes reincarnation, the soul has to be thought of as something that is distinct from the body.

The soul’s recurring journey from death to life and back again entails that it is embodied more than once. This view also seems to involve a concept of the soul as a substantial individual being, as opposed to a mode of the body. In the Phaedo the idea that the soul may be just a mode of the body is considered as an objection to the Socratic–Platonic position. An interlocutor in the dialogue raises this point. Could it be that what Socrates and Plato refer to as the soul is not a substantial individual entity, but more like a harmony? One may play a stringed instrument (a lyre, for example) and produce what appears to be more than the instrument (melodious sound); yet this is not a separate substance, but a mode of the lyre. Melodious sound is the way a lyre sounds when played, and if (so the interlocutor argues) the lyre is broken, the melodious sound will end:

The body is held together at a certain tension between the extremes of hot and cold, and wet and dry, and so on, and our soul is a temperament or adjustment of these same extremes, when they are combined in just the right proportion. Well, if the soul is really an adjustment, obviously as soon as the tension of our body is lowered or increased beyond the proper point, the soul must be destroyed, divine though it is—just like any other adjustment, either in music or in any product of the arts and crafts, although in each case the physical remains last considerably longer until they are burned up or rot away. (Phaedo, 86C; Tredennick’s translation)

In the dialogue, Socrates argues that the soul cannot be like the lyre and the music it makes, because the soul actually pre-exists the body; and, if the soul pre-exists the body, it is not identical with it. Socrates thereby seeks to break the analogy proposed, because the way a lyre sounds cannot exist before the lyre exists. The case for a pre-natal existence of the soul, developed in detail by Plato elsewhere in the same dialogue (and in others, too), deserves a brief comment here. For example, in the Meno he argues that knowledge is recollection of what the soul was aware of before birth:

[A man] would not seek what he knows, for since he knows it there is no need of the inquiry, nor what he does not know, for in that case he does not even know what he is looking for. […] Thus the soul, since it is immortal and has been born many times, and has seen all things both here and in the other world, has learned everything that is. So we need not be surprised if it can recall the knowledge of virtue or anything else which […] it once possessed […] for seeking and learning are in fact nothing but recollection. (Meno, 80E, 81D)

The most famous illustration of the “anything else” that is recalled by the soul involves the interrogation of a slave boy who, when prodded with the right questions, “rediscovers” a proof of the Pythagorean theorem (Meno, 85E–86A).

The Platonic case for pre-natal existence would be hard to defend today, but if it is even conceivable that the soul can pre-exist its body, then there is at least an appearance that the soul is not the body, and thus not a mere mode of the body. Another way to make Plato’s case against the soul being a mere mode is to appeal to our understanding of ourselves as substantial beings existing over time. Arguably, when you love a person, you love a concrete individual. But if the person, or soul, is a mode of something else (say, a living animal body), then it appears that your beloved is a phase or a shape of his/her body. Is it plausible to believe that the object of your love is a certain aspect of that body? Isn’t it more reasonable to believe that you love a substantial being and that, when your beloved dies, she is no more (at least not in this life), while her body remains? Socrates took something akin to this position and, in the Crito, he comforted his disciples, who were weeping over his immanent death, by claiming that they might bury his body, but he, Socrates, would be elsewhere. (We will return to this question when considering the work of Aristotle.)

Reincarnation means re-embodiment; and in Plato’s account of the soul the material body is not only something that is ever changing, but also it is that which effectively serves as a prison for the soul, and as such is evil (Phaedrus, 250C). As we examine further Plato’s view of the soul–body relationship, it is important to recognize that early philosophers were interested in the soul for more than purely theoretical reasons. They also sought to evaluate the moral and spiritual condition of the soul. According to Plato, the embodied soul is attracted by the pleasures of the body, such as those of food and drink and love-making (Phaedo, 64D). These pleasures distract the soul from its true purpose of being (what we might think of as the soul’s meaning of life), which is to reason about and know (or recollect) what is true. However, Socrates says:

I suppose the soul reasons most beautifully [without the need for recollection] when none of these things gives her pain—neither hearing nor sight, nor grief nor any pleasure—when instead, bidding farewell to the body, she comes to be herself all by herself as much as possible and when, doing everything she can to avoid communing with or even being in touch with the body, she strives for what is. (Phaedo, 65C; Brann’s translation)

What is are the immaterial Platonic Forms or Ideas, which are abstract objects like the concepts of justice, circularity, rationality, humanness, and so on. The soul possesses knowledge when it is focusing on these Forms and philosophizing about them and their relationships with each other. The soul is happy when it beholds the Forms directly, because what it ultimately desires more than anything else is the truth (Phaedo, 66b).

Plato seems to regard reason/intellect as that which alone constitutes the essence of soul, and tells his readers that the soul is nourished by reason and knowledge (Phaedrus, 247D). The less a soul is nourished by these, the greater its forgetfulness and resulting wrongdoing and the lower its level of re-embodiment. Thus Plato claims that

the soul that hath seen the most of being shall enter into the human babe that shall grow into a seeker after wisdom or beauty, a follower of the Muses and a lover; the next, having seen less, shall dwell in a king […] or a warrior and ruler; the third in a statesman, a man of business, or a trader; the fourth in an athlete, or physical trainer, or physician. (Phaedrus 1961, 248D–E)

Elsewhere Plato states: “Of the men who came into the world, those who were cowards or led unrighteous lives may with reason be supposed to have changed into the nature of women in the second generation” (Timaeus, 90E–91A). (While such a view would be labeled sexist today, we should note that Plato held a higher view of women than his contemporaries when he affirmed in the Republic that women can make ideal rulers). Furthermore, “those who’ve made gorging and abusing and boozings their care […] slip into the classes of donkeys and other such beasts” (Phaedo, 81E). In the Timaeus again, Plato expresses the view that the “race of wild pedestrian animals […] came from those who had no philosophy in any of their thoughts […] In consequence of these habits of theirs they had their front legs and their heads resting upon the earth to which they were drawn by natural affinity” (Timaeus 1961, 91E).

Plato’s position on pleasure and the body may seem to us today as too derisive, and we will not defend it; but it is worth appreciating that Plato’s teacher Socrates, and probably Plato himself, were veterans of a massive war, the Peloponnesian War (431–404 BCE) in which their side (Athens and her allies) was decisively defeated. Perhaps Plato’s warnings about bodily pleasure and being prey to other sensory desires stemmed from his (and other Athenians) belief that Athens’ entry into war was largely the result of a desire for worldly goods. His account on the soul definitely situates the soul as oriented toward more enduring goods than imperial wealth.

Let us consider further Plato’s understanding of the soul–body relationship. We have already touched upon his view of how bodily pleasures seduce the soul away from its proper activity of contemplating the Forms. When the soul is seduced in this way, events in the body causally affect it. For example, the eating of foods, the drinking of liquids, and sexual intercourse cause the soul to experience pleasure. Plato was also aware that the soul moves its physical body when it pursues, among other things, bodily pleasures, some of which it should forego. How does the soul move the body? When discussing the concept of motion, Plato claims that that which can move itself is the most powerful and superlative kind of mover (Laws, 894D). At one point, Plato suggests defining the word “soul” as “the motion which can set itself moving” (Laws, 896A), and he thinks of the soul as “the universal cause of all change and motion” (896B) because motion in a series that has a beginning must begin with the motion of a self-mover (894E; 895B). Motion that is produced in a thing by that thing itself is most like or akin to the motion of thought (Timaeus, 89A) and, as a result, when the soul moves the body that is its vehicle (Timaeus, 69C), it is the soul that governs and the body that is governed (Laws, 896C). In short, it is our souls that move us wherever we go (Laws, 898E) and Plato seems to believe that the soul moves the body by first setting itself in motion.

The soul, then, is a self-mover that moves the body. Is there anything more that might be said about the soul’s movement of the body? Plato believes that there is. In a passage in the Phaedo, at 97B–99D, Socrates informs his interlocutor that he once heard someone reading from a book by an earlier philosopher, Anaxagoras, in which the author claimed that mind is responsible for all things, and it orders the world and the objects in it in the best possible way. Socrates recollects how he thought he had discovered, to his great pleasure, a teacher after his own mind. However, upon reading Anaxagoras further, he discovered a man who did not acknowledge any kind of explanatory role for the mind. Socrates’ words deserve quotation in full:

And to me his [Anaxagoras’] condition seemed most similar to that of somebody who—after saying that Socrates does everything he does by mind and then venturing to assign the causes of each of the things I do—should first say that I’m now sitting here [in prison] because my body’s composed of bones and sinews, and because bones are solid and have joints keeping them separate from one another, while sinews are such as to tense and relax and also wrap the bones all around along with the flesh and skin that holds them together. Then since the bones swing in their sockets, the sinews, by relaxing and tensing, make me able, I suppose, to bend my limbs right now—and it’s through this cause that I’m sitting here with my legs bent. And again, as regards my conversing with you, he might assign other causes of this sort, holding voices and air and sounds and a thousand other such things responsible, and not taking care to assign the true causes—that since Athenians judged it better to condemn me, so I for my part have judged it better to sit here and more just to stay put and endure whatever penalty they order. Since—by the Dog—these sinews and bones of mine would, I think, long ago have been in Megara or Boeotia, swept off by an opinion about what’s best, if I didn’t think it more just and more beautiful, rather than fleeing and playing the runaway, to endure whatever penalty the city [Athens] should order. But to call such things causes is too absurd. (Phaedo, 98C–99A; Brann’s translation)

More generally, Socrates is suggesting something like the following. When we go to explain our bodily actions, it is misguided to think that we can ultimately explain them in terms of physical causes alone, without any reference to purposes (ends or goals). In other words, there are at least two kinds of explanations, one that is causal and the other that is teleological (telos is the Greek word for purpose, end, or goal). While it is no doubt true that, if Socrates (contrary to fact) had fled to Megara, his bones and sinews would have been caused to move in certain ways, it is also true in such a case that the movements of his bones, sinews, and body to Megara would ultimately have been explained by the purpose for which Socrates was fleeing his cell in Athens. From the first-person perspective of Socrates (the perspective of self-awareness or introspection), this purpose would have been something like “so that I save my life.” Moreover, as Socrates goes on to point out (Phaedo, 99B), there is a distinction between those things (in this case, bones, sinews, and the like) without which this purpose could not become active so as to do any explanatory work (what philosophers call “necessary conditions”) and the purpose itself. To maintain that the necessary conditions are the explanation itself is, Socrates claims, a most serious mistake.

So far, we have primarily surveyed Plato’s thoughts about the soul’s extrinsic nature, as it relates to the body and to reincarnation. Plato has equally interesting and important views about the soul’s intrinsic nature (its nature independently of its relationship to a physical body). What is not clear, however, is whether his views about the soul’s intrinsic nature are consistent.

For example, on the one hand, as we have already seen, Plato maintains that the soul is indestructible and imperishable. He explains this fact about the soul in terms of its indissolubility (Phaedo, 80A–B). Unlike bodies, which are composite and whose components are constantly changing (Timaeus, 43A), a soul keeps to the self-same condition (Phaedo, 80B) and is thereby likely to be non-composite, or without parts (Phaedo, 78C). Plato also stresses that the soul is akin to the invisible Forms, which are grasped by thought and not by the senses (Phaedo, 79A–D).

On the other hand, Plato claims that the soul has “parts,” whose existence is clearly manifested in everyday life. More specifically, the soul has three parts. On the one hand, there is the appetitive and lowest part of the soul, which does not comprehend reason (it is non-rational) but experiences pleasure and pain and has low desires (Timaeus, 71A, 77B). At the other extreme, there is the rational part of the soul (Republic, 440E), which is the part that beholds the Forms and ought to rule over the other two parts. In between these two parts of the soul is a third one, which is spirited in nature. This part’s function is that of rising to the occasion, in support of the rational part, when that one is at odds with the appetitive part. As Plato views the life of the soul, excessive pains and pleasures are its greatest enemies insofar as they tempt the soul to engage in inappropriate behavior. Pleasure is the greatest incitement to evil action, while pain is a deterrent to action that is good (Timaeus, 69D). Excessive pleasures provoke abuse of food, drink, and sex, while excessive pains elicit cowardly behavior. Reason must govern the unreasonable eagerness to attain the former and avoid the latter, and in order to do so it harnesses the emotion (e.g. anger) of the high-spirited part of the soul to support reason in its battle with the appetites. Plato goes so far as to locate the three different parts of the soul in different areas of the body. The rational part is located in the head; the appetitive in the midriff; and the high-spirited in between the other two, midway between the midriff and the neck, “in order that being obedient to the rule of reason it might join with it in controlling and restraining the desires when they are no longer willing of their own accord to obey the word of command issuing from the citadel” (Timaeus, 70A).

Plato’s assertion that the soul has parts is puzzling in light of his other claim, that the soul keeps to the self-same condition because it is likely without parts. Perhaps these three parts are not so much separable things that make up a soul (the way three people might make up a singing trio), but they are three capacities or powers possessed by a single soul. On this view, the appetitive part is the soul’s capacity to be subject to appetitive urges, the rational part is the soul’s power to reason, and so on. But, no matter how Plato’s two positions may be reconciled (if they can be reconciled at all), they serve to highlight an important issue, which will be with us throughout the remainder of this book. This issue is the question of whether the soul has or lacks parts, whether it is complex or simple in nature. Plato raised this matter but did not clearly resolve it. The contemporary philosopher David Armstrong has used Plato in an effort to support the view that the self does have parts (Armstrong 1999, 23). He points out that in the Republic Plato argues for the existence of parts of soul from the fact that we are the subjects of, and can consider acting for the purpose of, fulfilling either one, but not both, of two competing desires:

But, I [Socrates] said, I once heard a story which I believe, that Leontius the son of Aglaion, on his way up from the Piraeus under the outer side of the northern wall, becoming aware of dead bodies that lay at the place of public execution at the same time felt a desire to see them and a repugnance and aversion […] (Republic, 439E)

Contrary to what Armstrong (and, perhaps, Plato) would have us believe, if these desires are parts of the self, they are not substantive parts in the sense of being substantial entities in their own right, whose loss would entail a corresponding substantial diminishment in the size of the self. To see that this is the case, we can suppose that Socrates loses one or both of the desires—to see the dead bodies and not to see them (the loss of a desire is not an uncommon experience that each of us has). Does Socrates experience a substantial loss of himself? Not in the least. All of him will remain after the loss of either or both of these desires. Socrates will have changed, but not in the sense that there will be less of him in a substantive sense. He will survive this kind of psychological change in his entirety. Therefore, we will need an argument other than the one brought forth by Armstrong from Plato to support the idea that the self has substantive parts.

Regardless of whether Plato ever espoused a clear position on the matter of the soul’s substantive simplicity, he was aware of the soul’s nature as a unit in perception and cognition and of the problem that this poses for the idea that the soul has parts. In a discussion about knowledge and perception in the Theaetetus, Socrates asks: “Is it more correct to say that we see and hear with our eyes and ears or through them?” Theaetetus responds, “I should say we always perceive through them, rather than with them,” and Socrates retorts as follows:

Yes, it would surely be strange that there should be a number of senses ensconced inside us, like the warriors in the Trojan horse, and all these things should not converge and meet in some single nature—a mind, or whatever it is to be called—with which we perceive all the objects of perception through the senses as instruments. (Theaetetus, 184C–D)

In other words, Plato recognizes that it will not do to liken an individual mind to a group of individuals who are parts of a whole, where one person sees the lightning, another hears the thunder, yet another smells the rain, and yet one more feels the rain’s impact on his skin, but there is no single individual that is aware of all of these things at once. No; one and the same individual simultaneously sees the lightning, hears the thunder, and smells the rain whose impact he feels on his skin. Hence Plato reasons that the senses through which we are aware of the thunderstorm must be instruments of the soul that somehow converge at the single point that is the soul itself, which is the subject of awareness. Were this convergence not to obtain, there would be no single soul or mind that is aware of all that is going on, but only a multiplicity of perceivers. A fact that deserves noting is that this unity of consciousness of which Plato was aware is still something that puzzles contemporary brain scientists. Thus, in commenting about contemporary speculations about consciousness, John Searle says:

I need to say something about what neurobiologists call “the binding problem.” We know that the visual system has cells and indeed regions that are specially responsive to particular features of objects such as color, shape, movement, lines, angles, etc. But when we see an object we have a unified experience of a single object. How does the brain bind all of these different stimuli into a single, unified experience of an object? The problem extends across the different modes of perception. All of my experiences at present are part of one big unified conscious experience […]. (Searle 1997, 33)

We will have more to say about the unity of consciousness in our discussions of subsequent philosophers’ views of the soul.

Aristotle

Without question, the other major Greek philosopher of the soul was Aristotle. Though he was a student of Plato at the Academy in Athens, he was not one who blindly accepted his teacher’s views. Some passed his scrutiny, others did not.

Like Plato, Aristotle believes that the soul gives life to its body. Because the soul is the first principle of living things (Aristotle 1986: De anima, 402a), Aristotle maintains “that the ensouled is distinguished from the unsouled by its being alive” (De anima, 413a). In short, everything that is alive has a soul, including organisms like plants and trees. One should not conclude, however, that Aristotle believes that plants and trees see, hear, and think. To avoid saying anything like this, he distinguishes between kinds of soul, which are hierarchically arranged. The lowest kind of soul, which is the kind that plants and trees have, is what Aristotle terms a “nutritive” soul. Whatever has it is alive (De anima, 415a). It is best to think of a nutritive soul as the principle that is responsible for the nourishment, growth, and decay of an organism. “Now of natural bodies some have life and some do not, life being what we call self-nourishment, growth and decay” (De anima, 412a).

According to Aristotle, one step up from the nutritive soul is the sensitive soul, which is the soul that accounts for perception in the form of touch, sight, smell, taste, and hearing. It is the existence of the sensitive soul that distinguishes animals from plants and trees. Nothing that is alive is an animal, unless it is able to perceive (De anima, 413b). Because animals both live and perceive, the question arises as to whether they have two souls, a nutritive one and a sensitive one. Aristotle makes it clear (at 414b) that they have only one soul, because the lower member of the hierarchical series (in this case, the nutritive) is present in the form of its powers (nourishment, growth, and decay) in the higher soul. In other words, the higher soul incorporates the powers of the lower into itself and thereby eliminates the need for the lower-level soul itself.

Human beings are animals, but different ones from beasts (nonhuman animals), so the question arises as to what distinguishes humans from the beasts. According to Aristotle, a human being possesses a kind of soul that is one step further up the ladder from the kind that is possessed by beasts. The kind of soul in question is one that enables a human being to think, suppose, and know (De anima, 413b, 429a). Its possession renders a human being a rational animal. In keeping with the point made in the previous paragraph, a human being does not have three souls but only one, where the rational soul incorporates the nutritive and perceptive powers that define the lower-level souls.

While Aristotle agrees with Plato about the existence of the soul and its life-giving power, he takes issue with several of his teacher’s beliefs about the soul. For example, consider the issue of how the soul is related to the body. According to Plato, the soul’s relationship to a body is contingent. The body you have now is not your body in virtue of some essential necessity; you could have had a different body. (And, if Plato is right about reincarnation, you will come to have a different body.) Formally, Plato’s position can be put this way: while a rational soul A gives life to, and has, a human body B, A could have given life to, and could have had, human body D. Moreover, rational soul C, which gives life to, and has, D could have enlivened and had B. Indeed, on Plato’s view, rational soul A could have had the body of a dog. Aristotle believes that this kind of radical contingency between a soul and its body is wrong:

But there is one absurdity that this [Platonic view] has in common with most theories about the soul. The soul is connected with the body, and inserted into it, but no further account is given of the reason for this nor of the condition that the body is in. Yet this would seem to be required. For it is by their partnership that the body acts and the soul is affected, that the body comes to be moved and the soul produces motion. And none of these is possible for things whose mutual connection is contingent. […] The point is, however, that each body has its own form and shape. (De anima, 407b; Lawson-Tancred’s translation)

Aristotle believes that an adequate account of the soul must be able to explain why it is that a particular soul has a particular