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- Herausgeber: John Wiley & Sons
- Kategorie: Geisteswissenschaft
- Serie: This is Philosophy
- Sprache: Englisch
This is Philosophy of Mind presents students of philosophy with an accessible introduction to the core issues related to the philosophy of mind.
- Includes issues related to the mind-body problem, artificial intelligence, free will, the nature of consciousness, and more
- Written to be accessible to philosophy students early in their studies
- Features supplemental online resources on https://www.wiley.com/en-us/thisisphilosophy/thisisphilosophyofmindanintroduction and a frequently updated companion blog, at http://tipom.blogspot.com
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Seitenzahl: 455
Veröffentlichungsjahr: 2013
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Table of Contents
Series page
Title page
Copyright page
Dedication
How to Use This Book
Acknowledgments
1: Meet Your Mind
Aspects of Mind
Philosophical Problems
Conclusion
2: Substance Dualism
Arguments for Substance Dualism
Mind–Body Interaction as a Problem for Substance Dualism
Conclusion
3: Property Dualism
Introducing Property Dualism: Qualia and the Brain
The Inverted Spectrum
Attack of the Zombies
The Knowledge Argument
The Explanatory Gap Argument
Does Property Dualism Lead to Epiphenomenalism?
How Do You Know You're Not a Zombie?
Conclusion
4: Idealism, Solipsism, and Panpsychism
Solipsism: Is It Just Me?
Idealism: It's All in the Mind
Panpsychism: Mind Is Everywhere
Conclusion
5: Behaviorism and Other Minds
Behaviorism: Introduction and Overview
The History of Behaviorism
Objections to Behaviorism
The Philosophical Problem of Other Minds
Conclusion
6: Mind as Brain
Introducing Mind–Brain Identity Theory
Advantages of Mind–Brain Identity Theory
A Very Brief Overview of Neuroscience
Some General Remarks about Identity
Arguments against Mind–Brain Identity Theory
Conclusion
7: Thinking Machines
Can a Machine Think?
Alan Turing, Turing Machines, and the Turing Test
Searle's Chinese Room Argument
Responses to the Chinese Room Argument
The Silicon Chip Replacement Thought Experiment
Symbolicism versus Connectionism
Conclusion
8: Functionalism
The Gist of Functionalism
A Brief History of Functionalism
Arguments for Functionalism
The Varieties of Functionalism
Arguments against Functionalism
Conclusion
9: Mental Causation
The Problem of Mental Causation
Basic Views of Interaction
Qualia and Epiphenomenalism
Anomalous Monism
The Explanatory Exclusion Argument
Conclusion
10: Eliminative Materialism
Introduction and Overview
Basic Ingredients of Contemporary Eliminative Materialism
Arguments for Propositional Attitude Eliminative Materialism
Arguments against Propositional Attitude Eliminative Materialism
Qualia Eliminative Materialism: “Quining” Qualia
Conclusion
11: Perception, Mental Imagery, and Emotion
Perception
Mental Imagery
Emotion
Conclusion
12: The Will: Willpower and Freedom
The Problem of Free Will and Determinism
Sources of Determinism
Compatibilism
Incompatibilism
What Might Free Will Be, If There Were Any Such Thing?
Conclusion
13: Intentionality and Mental Representation
Introducing Intentionality
The Inconsistent Triad of Intentionality
Internalism versus Externalism
Theories of Content Determination
Conclusion
14: Consciousness and Qualia
Optimism about Explaining Consciousness
Focusing on Several Different Uses of the Word “Conscious”
Rosenthal's Higher Order Thought Theory of Consciousness
First Order Representation Theories of Consciousness
Conclusion
15: Is This the End? Personal Identity, the Self, and Life after Death
Problems of Personal Identity
The Problem of Persistence
Approaches to the Problem of Persistence
Life after Death
Conclusion
Index
This Is Philosophy
Series editor: Steven D. Hales
Reading philosophy can be like trying to ride a bucking bronco—you hold on for dear life while “transcendental deduction” twists you to one side, “causa sui” throws you to the other, and a 300-word, 300-year-old sentence comes down on you like an iron-shod hoof the size of a dinner plate. This Is Philosophy is the riding academy that solves these problems. Each book in the series is written by an expert who knows how to gently guide students into the subject regardless of the reader's ability or previous level of knowledge. Their reader-friendly prose is designed to help students find their way into the fascinating, challenging ideas that compose philosophy without simply sticking the hapless novice on the back of the bronco, as so many texts do. All the books in the series provide ample pedagogical aids, including links to free online primary sources. When students are ready to take the next step in their philosophical education, This Is Philosophy is right there with them to help them along the way.
Forthcoming:
This edition first published 2014
© 2014 John Wiley & Sons, Inc.
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Library of Congress Cataloging-in-Publication Data
Mandik, Pete.
This is philosophy of mind : an introduction / Pete Mandik.
pages cm. – (This is philosophy ; 2996)
Includes bibliographical references and index.
ISBN 978-0-470-67447-5 (alk. paper) – ISBN 978-0-470-67450-5 (pbk. : alk. paper) 1. Philosophy of mind. I. Title.
BD418.3.M3535 2013
128'.2–dc22
2013006408
A catalogue record for this book is available from the British Library.
Cover design by www.cyandesign.co.uk
For Rachelle and Delia
How to Use This Book
Despite the enormous advances in understanding that humans have made about themselves and the world around them, many mysteries remain. Many of those mysteries have to do with the mind. This guide to philosophical approaches to the mind is intended to be useful both to students taking a course with a teacher and readers tackling the subject on their own. The book's 15 chapters were written with a typical 15-week university semester in mind, though it is not essential that all the chapters be read or read in precisely the order in which they are presented. Although there is cross-referencing between the chapters to aid those reading from beginning to end, the chapters can serve as stand-alone units, with each chapter ending with an annotated bibliography. As much as possible, the annotated bibliographies contain links to readings available on the Internet.
Here's another thing for Internet users to keep in mind: I encourage readers—both students and teachers—to consult the companion blog for this book, located at http://tipom.blogspot.com. The blog is a frequently updated online resource compiling relevant additional readings, videos, visual aids, pointers to relevant scientific work, and definitions of key terms. Teachers in particular are encouraged to start off on the blog at http://tipom.blogspot.com/p/teacher-tips.html, although students might get something out of looking at that part as well!
Acknowledgments
For valuable comments on early versions of some of this material, I am grateful to Jeff Dean, Steven Hales, Chase Wrenn, and several anonymous referees. Very special thanks for highly thorough help goes to Helen Kemp, Josh Weisberg, and Tad Zawidzki.
For love, support, and advice based on a truly humbling grasp of English, I thank my wife, Rachelle Mandik.
1
Meet Your Mind
1.1
Unless you've lost your mind, or never had one in the first place, likely you'll agree that your mind is a pretty special part of you. Maybe, even, your mind is all that you are—maybe you're nothing but a mind. Maybe that's too extreme, but you do have to admit that your mind is an excellent candidate for your single most defining feature. It's certainly a much better candidate for the seat of your you-ness than your foot, your liver, or your haircut. So what is this special thing, this mind of yours? In this chapter we'll examine some of the main aspects of the mind that philosophers have been interested in. We'll also look at some of the main philosophical problems concerning the mind.
Aspects of Mind
1.2
Because you have a mind, there are certain special things you can do. You can think and perceive. You can enjoy and you can suffer. You can learn from the past and plan for the future. You can make choices. You can spring into action. You can dream.
1.3
Because you have a mind, there are special things that you have. You have beliefs. You have feelings. You have mental images. You have memories. You have the reasons for the way that you act.
Thought and experience
1.4
Stop and attend to your mind right now. What do you notice about your own mind? What's in it that isn't in your foot, your liver, or your haircut? One striking collection of items populating your mental landscape is your experiences, especially your sensory experiences. You see colors and shapes. You hear noises and melodies. You feel textures and temperatures. Further, you have experiences besides those that are straightforwardly sensory. You experience a faint twinge of anxiety or are overcome by an intense dread. These are your emotional experiences.
1.5
In addition to your experiences, when you attend to your mind you may notice various thoughts that you have. You are thinking when you believe that there are leftovers in the fridge, wonder whether the weather will be nice tomorrow, or doubt that you will win a million dollars. Beliefs, judgments, and doubts are kinds of thoughts.
1.6
Like philosophy in general, philosophy of mind is rife with controversy. One sort of controversy concerns the view that our mental states may be sorted into the experiences and the thoughts. Are these groups too few? Perhaps there is more to the mind than thoughts and experiences. Perhaps mental images or emotions are neither thoughts nor experiences. Another perspective is that sorting mental states into thoughts and experiences is to create more groups than there really are. Maybe all mental states are really a kind of experience. Or, instead, all are just thoughts. We will return to such controversies later. Suffice for now to say that the most widely held view on this matter is that there are both thoughts and experiences and there may be other sorts of mental states as well.
Conscious and unconscious
1.7
At least since the time of Freud, if not earlier, people have been familiar with the idea that some of our mental states occur unconsciously, while others occur consciously. Freudian psychologists sought to explain much human behavior in terms of unconscious desires such as the unconscious desire to kill one of your parents and have sex with the other one. Perhaps another example of the unconscious is the unconscious knowledge that guides an expert as they hit a tennis ball or play a musical instrument. They aren't consciously thinking of what they're doing, and when they do try to consciously attend to, for instance, what comes next in the music that they are performing, this act of consciousness makes them make a mistake.
1.8
In contrast to such unconscious mental states there are, of course, the conscious ones. Consider your experience of the words that you are reading right now. In attending deliberately to the words on the screen or page you consciously experience the way they look (or feel, if you are reading this in Braille).
Qualia
1.9
One fascinating aspect of our mental states, an aspect mostly associated with our conscious sensory states, is something that philosophers call a quale (singular, pronounced KWAH-LAY) and qualia (plural, pronounced KWAH-LEE-AH). The word “qualia” comes from the Latin for “qualities,” and philosophers of mind reserve the term for special qualities of mental states. One important phrase that helps philosophers of mind convey the idea of qualia is the phrase “what it's like.” Consider the question of what it's like to see red as opposed to seeing blue. Imagine the difficulty in explaining to someone who has been blind their whole life what it's like to see red. Would it really suffice to describe it as like seeing something warm or seeing something that makes people hungry? Or instead must such descriptions necessarily leave something out? Consider the philosophers' puzzle of the inverted spectrum: Is it possible that what it's like for you to see red is the same as what it's like for me to see green and vice versa? These are difficult philosophical questions. Anyway, the main point for now is that insofar as you followed this brief discussion employing the phrase “what it's like” in connection with conscious sensory experiences, you have a feel for what qualia are. Qualia are the subjective aspects of experiences, the aspects of what it's like to have experiences.
Sensory perception
1.10
It's difficult to deny the importance of sensory perception. One old and influential philosophical position, empiricism, even goes so far as to hold sensory perception to be the source of all our ideas and knowledge: Nothing gets in the mind without first getting in the senses.
1.11
Saying what makes sensory perceptions distinctive is an interesting philosophical problem. What serves to distinguish, say, visually perceiving a cat from merely thinking about a cat? One sort of answer to this question is that in the case of perception there must be a direct sort of causal interaction between the perceiver and the thing perceived whereas there need not be such interaction between a thinker and the thing thought about. You can think about things that are too small or too far way to have noticeable effects on you, but noticeable effects are a requirement on the perception of perceptible objects.
Emotion
1.12
Emotions are a very interesting sort of mental state. Consider thinking, without having any emotional reaction one way or another, that there is a dog in the room. Now compare this to being angry or being happy that there is a dog in the room. What differentiates the mere thought from the anger or the happiness? In the case of anger we might be tempted to say there's something intrinsically negative in it, whereas the mere thought is neither positive nor negative. There's something to this suggestion, but it seems not enough. The fear that there's a dog in the room is negative too, but it doesn't seem to be exactly the same sort of thing as anger. So there must be more to these negative emotions than simply adding some negativity to otherwise neutral thoughts.
Imagery
1.13
Here's an exercise of imagination. Imagine a capital letter “J” and a capital letter “D.” Now imagine that the letter “D” is rotated 90 degrees counterclockwise and placed on top of the “J.” Now answer this question: What common object does the resulting figure resemble? If you answered “umbrella” you've thereby demonstrated the power of mental imagery. The word “imagery” is closely associated with things of a visual nature, but there can also be nonvisual mental imagery. It thus makes sense to talk about forming mental images of smells or imagining hearing certain sounds. One thing that's interesting about mental imagery is the way it seems to sit astride the contrast we drew earlier between thoughts and sensory experiences. Images are more similar to sense experiences in some ways and more similar to thoughts in others.
1.14
Let us note now a similarity that thoughts and images share that distinguishes each from sensory perception. We can exert a kind of direct control on our thoughts and images that we cannot exert on what we perceive. Suppose you see a red stop sign. While you can easily imagine or think about the stop sign as being some other color, you cannot simply choose to perceive the red stop sign as green. If you wanted to see it as green, you'd have to exert some indirect control on your perception, like painting the sign green.
Will and action
1.15
We have, so far, contrasted thoughts and experiences, conscious states and unconscious states, perception and imagery. Here's another contrast of special importance: It's the contrast between what happens to us and what we do. Where perceptions and experiences are things that happen to us, action and will clearly concerns what we do. One way in which some philosophers have sought to explain the difference between what we do and what merely happens to us is by making reference to a special faculty of will, a faculty by means of which events are caused that count as actions we've performed instead mere happenings that occur.
Self
1.16
Consider the following questions that concern personal identity: Who are you? What distinguishes you from other people? What sort of thing is a person? What distinguishes people from mere objects?
1.17
Some have sought to answer such questions by referring to a certain kind of entity—a self. What is a self? It's what makes you a somebody instead of nobody at all, a person instead of a mere object. And it's what serves to distinguish you from everybody else. Some philosophers have denied that there is any such thing as a self. The philosopher David Hume, being an empiricist, stressed the grounding of what we know in what we can perceive with the senses. Some think of the self as the thing that has experiences, a thing separate from the experiences themselves. But Hume invites us to pay close attention to our experiences and notice that all we are able to attend to are the experiences themselves, for instance, an experience of heat, of color, or of shape. Try as we might, looking inward, we never catch a glimpse of any entity doing the glimpsing—we find only what is glimpsed. Perhaps, then, the self is nothing at all.
Propositional attitudes
1.18
One way in which philosophers think about certain mental states, especially mental states such as beliefs and desires, is as what philosophers call “propositional attitudes.” When a person has a propositional attitude, there is a proposition—roughly, a declarative sentence, a sentence that may be either true or false—toward which they bear an attitude, examples of which include believing, doubting, wondering, judging, desiring, fearing, and intending. Consider the following examples, and note that each attitude is in italics and the proposition toward which the attitude is directed is in bold.
1.19
Other examples of propositional attitudes are not as obvious as 1–4, but nonetheless, we can identify the proposition toward which an attitude is directed. Consider these cases:
In 5 and 6, the attitudes are obvious: intending in the case of 5 and desiring in the case of 6. However, what are the propositions in question? We can answer that question by considering another: What proposition has to be true for Eileen to accomplish what she intends and what proposition has to be true for Franklin to obtain what he desires? The answer to that question is this: The two propositions that must be true are “Eileen goes to the movies on Saturday” and “Franklin eats the biggest piece of pizza.” We can now take this information and assemble versions of 5 and 6 that more closely resemble 1–4. While it may sound a little weird to describe things in the following way, there's nothing strictly incorrect about 5* and 6*:
Philosophical Problems
1.20
We've seen some of the main aspects of mind that have interested philosophers, but to see what really interests philosophers we need to look at the puzzles and problems that arise when we try to understand aspects of the mind. First and foremost among these problems is that old classic, the mind–body problem.
Mind–body problem
1.21
When we contemplate the various mental states and mental properties it may strike us how very different they are from physical states and properties. But what makes something physical? First off, consider your own body. Your body is a physical thing, and it has the sorts of properties—physical properties—that are the proper study of physics and other physical sciences like chemistry. Your body has mass, it takes up a certain volume of space, it moves through space with a certain momentum, and it has various chemical constituents (e.g., hydrogen, oxygen, and carbon). The human body is not the only thing worth calling a “physical body.” Tables and chairs are physical bodies. So are rocks rolling down hills and apples falling out of trees (as are the hills and the trees). So, anyway, minds and mental properties seem to be very different from physical bodies and physical properties. We are led, then, to wonder what sort of relations there can be between mental things and properties on the one hand and physical things and properties on the other.
1.22
So, now that we have a bit of a feel for what minds and bodies are, what is the mind–body problem? It's probably best to think of it as a cluster of closely related problems. The main problems in this cluster are:
1.23
To help get a further feel for the mind–body problem, it helps to contemplate the ideas of the one philosopher who has been most central to subsequent discussions of the mind–body problem, the philosopher René Descartes. Descartes thought that the mind was radically different from physical bodies. He held that minds were essentially thinking things that didn't take up any space and that physical bodies were essentially unthinking things that did take up space. This is the essence of his substance dualism, which we will discuss at much greater length in chapter 2.
1.24
Given how radically different minds and bodies are supposed to be, a puzzle arises about how they can ever interact. Call this the problem of interaction. We'll say a lot more about this problem in chapter 9, but for now let's look at a quick sketch. To see how this problem arises for Descartes' substance dualism (aka Cartesian substance dualism), let's take this in a series of steps. First, note that minds and bodies do seem to interact. In fact, there are two directions of interaction, one for perception and one for action. In the case of perception, something happens in the world that has a causal effect on our minds. A car explodes causing us to see a ball of fire and hear a loud BOOM! In the case of action, something happens in the mind that has a causal effect on the world. Suppose I wanted to blow up a car. I have, in my mind, an intention to make things go BOOM! Next, I formulate a plan in my mind to gather the required explosives. And eventually, in the world, there's a mighty explosion.
1.25
Let's go on now to the second step in seeing what's problematic about the problem of interaction for Cartesian substance dualism. Note what usually happens when one thing causes another. They must be at the same place at the same time. To light the fuse, the flame must be brought near it. To boil the water, the pot must be put on the stove. To heal the wound, the medicine must be put on it. Causation seems to require proximity. Even in cases that look like action at a distance, like when a remote is used to turn on a television, something crosses the space in between, in this case invisible radiation. However, in Cartesian substance dualism, while bodies take up space, minds do not. Taking up no amount of space, they therefore are nowhere. They simply aren't located in space. How, then, can anything happening in space affect or be affected by anything outside of it? And here's a related problem: How come things happening in your mind have a direct effect on your body but not on mine?
1.26
To avoid the problem of interaction, as well as other problems that arise for Cartesian substance dualism, many philosophers of mind have been driven to reject dualism and embrace some version or other of monism. If we describe dualism as the view that there are fundamentally two sorts of things in the universe, the mental and the physical, then we can describe monism as the view that there is only one sort of thing. Maybe, then, everything is mental. (That's an option we'll explore further in chapter 4.) Or, to take a more popular option, maybe everything, including your mind, is physical. How, though, can the mind be physical? Well, perhaps the right way to think of this is to just say that your mind is your brain (see chapter 6). This would certainly resolve the problems surrounding interaction, for, clearly, brains can have effects on and be affected by physical bodies. However, this sort of solution runs into other problems.
1.27
If the mind is a physical thing like a brain, it still seems that, in addition to its physical properties, it also has distinctively mental properties. Take, for example, qualia. What it's like to see red or feel pain is something I know only from the inside. No amount of investigation of my brain from the outside seems sufficient to reveal the nature of my qualia. It has therefore seemed plausible to many philosophers that qualia are a kind of nonphysical mental property. This kind of thinking leads to a different kind of dualism than the dualism of Descartes. As we'll explore further in chapter 3, this is a dualism of properties instead of a dualism of substances.
Other problems
1.28
While the mind–body problem is perhaps the central problem in philosophy of mind, there are other problems as well, and we'll take a very quick look at them in the remainder of this chapter. In particular, we will be looking at the following problems:
the problem of perceptionthe problem of other mindsthe problem of artificial intelligencethe problem of consciousnessthe problem of intentionalitythe problem of free willthe problem of personal identityThe problem of perception
1.29
The problem of perception involves a conflict between two individually plausible ideas about the nature of perception. The first is that when we perceive, we are thereby in a direct sort of relation to some object in the world. When I open my eyes and see a red book on the table before me, I am thereby in a relation with that red book. The red book is there, and my perceiving it is a kind of openness to this object in the real world.
1.30
The second idea about perception is an idea that comes from philosophical reflection on misperceptions and hallucinations. Perhaps you seem to see a pink elephant in the room with you, but as a matter of fact you are really dreaming or hallucinating. Since there is no pink elephant in the room with you, whatever you are perceptually aware of, it cannot be a pink elephant. Many philosophers have hypothesized that this something that you are thereby aware of while dreaming or hallucinating is a mental something. Let's call it a perceptual idea. In hallucinating a pink elephant, you aren't aware of any real pink elephant, you are aware of an idea of a pink elephant.
1.31
Viewed from the “inside,” both an accurate perception of a real object and a false perception of a hallucinated object can seem just the same. Since they can seem the same, there has to be something in common between the two situations. One sort of view that some philosophers have found attractive is to say that what's common to both the accurate perceptual case and the false hallucinatory case is that what one is really directly aware of is an idea in one's mind. Thus, even when I accurately perceive a red book on the table, I'm only indirectly aware of the red book. What I'm directly aware of is the idea of the red book. So, both the accurate perception of a red book and the hallucination of a red book are something very similar, for both involve a direct awareness of an idea in my own mind. However, many philosophers have found this to be an unhappy result. If all we are ever directly aware of are the insides of our own minds, the so-called external world starts to sound like some extra stuff that might as well not be there anyway. The proposed irrelevance of the real world strikes many as a deeply disturbing idea. These sorts of ideas, and the philosophical responses to them, are going to be explored more thoroughly when we get to chapters 4 and 11.
The problem of other minds
1.32
Suppose you see someone acting as though they were in pain and it occurs to you that they are only acting. A very good actor can act convincingly as if they are in pain without actually being in pain. A good actor can do this for other mental states besides pain—they can act hungry, angry, confused, deranged, or enraged without actually being in those mental states. The very possibility of playacting helps to highlight the contingent relationships between our inner mental lives and our outward behaviors. (Sad behavior is related to sadness only contingently if it's possible to have sadness without the behavior or vice versa.) However, given the assumption that the relation between mind and behavior is contingent, the possibility arises that those other human bodies that you see everyday actually are moving and speaking without any inner mental lives at all. Now, if that is a genuine possibility—a possibility that you can't rule out simply by observing behaviors—then the following question arises: If you do know that others have minds, how do you know it? The problem of answering this question is the problem of other minds.
1.33
One sort of solution to the problem of other minds is to adopt a kind of behaviorism. On this sort of view, what a mental state is is something closely tied to particular kinds of behaviors. And so, regardless of whether a mental state belongs to you or someone else, what ultimately grounds your knowledge of the mental state is knowledge about certain kinds of behavior. We will take up further discussion of both behaviorism and the problem of other minds in chapter 5.
The problem of artificial intelligence
1.34
The way we've talked about the problem of other minds so far has been in connection with other people and to ask whether they have minds (and if they do, how we know that). Another sort of question we can ask is whether things that are very different from people can nonetheless have minds. What about, for example, computers and robots? In science fiction stories we are often presented with futuristic machines capable of thinking and behaving intelligently. Could there ever be, in real life, artificial forms of genuine intelligence? Can a machine think? Some philosophers answer “yes.” They say that humans themselves are a kind of machine, and that our own brains are a kind of computer. This is a version of a view known as functionalism, to be explored further in chapters 7 and 8.
1.35
Now, if this latter kind of idea is correct, that humans themselves are kinds of thinking machines, the question arises of how such machines—human machines—work in order to give rise to thoughts. If we are thinking machines, then what are the general mechanical requirements on being a thinking thing? What sorts of things would you have to build into a machine if you were going to give it the power to think?
1.36
One sort of proposal that has received a lot of attention from philosophers is that thinking is essentially linguistic and that the general mechanical requirements on thinking can only be satisfied by a machine that implements a language of thought. This hypothetical language of thought is a system of symbols that are combined in various rule-governed ways to form the various thoughts—beliefs, desires, etc.—that we have. As will be discussed further in chapter 7, the language of thought hypothesis is highly controversial, and many of its opponents propose that mechanical minds will need to be much more explicitly brain-like, and be constructed as highly connected networks—artificial neural networks composed of parallel distributed processors.
The problem of consciousness
1.37
Regardless of whether thinking is best explained mechanistically by reference to an inner symbol system, there are separate questions about how to explain other aspects of the mind, aspects beyond simply thinking. What about conscious sensations like a feeling of pain or a visual sensation of a bright shade of red? How can a mechanical or physical system have those aspects of mentality most distinctive of consciousness? Some philosophers have held that those aspects of consciousness, like the quale that goes along with seeing a bright shade of red, will never be explained by any kind of physical process. Some philosophers hold that there's an explanatory gap—no matter how much you may know about the physical processes in some creature's brain, you'll never be able to explain why there's a red sensation versus either a green sensation or no sensation at all. Other philosophers are far more optimistic about explaining consciousness, and we will examine, in chapter 14, proposed philosophical explanations of consciousness.
The problem of intentionality
1.38
Let's leave aside conscious sensations for just a moment and go back to questions about thinking. Earlier we were wondering about the requirements of being able to think. We mentioned the problem of whether thinking requires the existence of a language of thought. But there's another sort of problem connected to thinking, and it's a problem that we might state in this way: What sort of relation is it that takes place between a thinker and the things the thinker thinks about? This problem is the problem of intentionality.
1.39
Another way of stating the problem is in terms of “aboutness.” When we think, we think about things. I'm thinking about the planet Jupiter right now. Jupiter is one thing; my thought about it is another. But what is this “aboutness”? Is it a relation between Jupiter and me? If aboutness is a relation, then it looks like it's a very weird sort of relation. One thing that's really weird about “aboutness” is that I can think about things that don't even exist. I can think about unicorns—magical horses with horns—even though there really is no such thing. The problem of intentionality, the problem of explaining “aboutness,” will be taken up in chapter 13.
The problem of free will
1.40
It seems to be a pretty important part of our conception of ourselves that we take ourselves and others to do certain things freely. On the face of it, it looks like a pretty important part of deciding whether someone is morally responsible for something is to decide whether or not they did it of their own free will. However, perhaps the very idea of free will is mistaken. Perhaps everything that happens has to happen that way (it's all fated or predetermined) and thus there's really no such thing as a person acting of their own free will. Everything that a person does is actually something that they were made to do by a complicated network of causes involving both biological and societal factors. Or maybe not. The problem of free will, taken up in chapter 12, is the problem of whether there is any, and if so, what its nature is.
The problem of personal identity
1.41
So-called identical twins aren't truly identical. The Olsen twins, Mary-Kate Olsen and Ashley Olsen, aren't truly identical, since they aren't one and the same person. They are merely similar. True identity has to do with the conditions under which something counts as one and the same.
1.42
Here's a general problem about identity: How much can a single thing change without becoming a second thing? Suppose I take a precious wooden chair and burn it until it's a pile of ash. Many people would regard that as a second thing: I no longer have a chair, I have a pile of ash. Another series of changes I can introduce to the chair is to gradually replace parts of it. One day I replace one of the legs, another day I replace the seat, and so on, until each part has been replaced and the resulting chair has none of the original wood in it. Is the chair I have after making all these replacements one and the same as the chair I started with? Or have I instead gradually destroyed one chair while creating a second one?
1.43
These sorts of puzzles about identity can be applied to entities besides chairs. From birth to adulthood, a person undergoes many changes. During their life, cells in their body die and are eliminated as waste, while new cells grow to replace them. This replenishment of materials is one of the main functions of the nutrition we take in through food and drink. Like the chair described earlier, a person has their parts (at molecular and cellular levels) replaced. An adult is no longer a baby. But is the adult one and the same person as the baby? Did you used to be a baby, or are you instead some other person who has replaced the baby?
1.44
One of the greatest changes that occurs to a person's body is that their body will die. Many religious traditions hold that there is life after death—that a person can continue their existence despite the death of their body. Perhaps their life after death is a purely spiritual existence in a nonphysical heaven or hell, or perhaps they are reincarnated and live in a new body. Either way, different positions concerning the mind–body problem and personal identity have different things to say about whether and how life after death might be possible. A functionalist who rejects substance dualism can nonetheless embrace the possibility of life after death. On one such version of the view, the relation of mind and body is analogous to the relation, in computers, between software and hardware. Surviving death is fundamentally the running of an old piece of software on a new piece of hardware. We will further explore the questions of personal identity and life after death in chapter 15.
Conclusion
1.45
The mind is most certainly one of the strangest and most wonderful parts of existence, and surely plays a central role in what it means to exist as a person. However, so much about the mind is ill understood, and there are many controversies amongst philosophers about how best to tackle the various topics related to the mind, topics such as feeling, thinking, and acting. Some of these controversies concern the most vexing problems in all of philosophy. Such problems include the problem of free will, the problem of artificial intelligence, and the question of what, if anything, happens to us after we die.
Annotated Bibliography
Bourget, David and Chalmers, David (eds.) (2012) “Philosophy of Mind, General Works,” PhilPapers, full text available at http://philpapers.org/browse/philosophy-of-mind-general-works, accessed February 5, 2013. This frequently updated online bibliography contains many entries with abstracts and links to the full text of articles.
Mandik, Pete (2010) Key Terms in Philosophy of Mind (London: Continuum). More than just a dictionary of philosophy-of-mind terminology, this book also contains entries on key texts and key thinkers in the philosophy of mind.
Mandik, Pete (ed.) (n.d.) “Further reading,” in This is Philosophy of Mind: The Blog, http://tipom.blogspot.com/search/label/Further%20reading. A frequently updated collection of additional readings on various topics in the philosophy of mind.
2
Substance Dualism
2.1
Consider, just for a moment, something horrible. Consider what would happen to you if your body, including your brain, were totally destroyed. Imagine your body falling into a vat of acid or a pit of lava, its molecules violently and completely scattered in all directions. Question: Could you survive such a horrible event? On one view, the answer is “yes.” On this view you are your mind and your mind is a completely distinct thing from your physical body. Surviving death, then, is easy to do.
2.2
The idea that you are nonphysical and wholly distinct from your physical body is found in many religious traditions. However, our concern here is not with religious approaches to such an idea, but instead with philosophical ones. We will examine the main philosophical reasons in favor of and against the view known as substance dualism.
Arguments for Substance Dualism
2.3
Philosophers are very interested in examining arguments, both pro and con, for various positions. Philosophers of mind are no exception. Here we'll take a look at three kinds of arguments for substance dualism. They are (1) Leibniz's law arguments, (2) explanatory gap arguments, and (3) modal arguments. Along the way we'll also look at some criticisms of these arguments.
Leibniz's law arguments
2.4
At the heart of substance dualism is the idea that your mind and your brain are two distinct things, not one and the same thing. At the heart, then, is the idea of the nonidentity of two things. Central to the logic governing the ideas of identity and nonidentity is a principle of reasoning philosophers and logicians have come to call “Leibniz's law.” For our purposes, we can represent Leibniz's law as the indiscernibility of identicals, the principle that if x and y are one and the same, then x and y must have all of their properties in common. And if there is some property that the one has and the other lacks, then x and y are distinct. They are two distinct things, not one and the same thing.
2.5
Leibniz's law is obviously relevant to substance dualism. If there are one or more properties that your mind has and your body lacks, or that your body has and your mind lacks, then it follows by Leibniz's law that your mind and your body are distinct. A similar kind of reasoning attempts to show that the mind is not identical to any physical thing—any physical body, object, or system. Crucial to such lines of reasoning is to identify some property that minds have and physical things lack, or vice versa.
2.6
There are several ways in which different approaches to substance dualism might try to characterize the very different natures of minds and physical bodies. We will turn now to look at five alleged differences between minds and physical bodies.
2.7
The first alleged difference between minds and physical bodies originates with Descartes. He holds that physical bodies are spatial and that minds are not. But what does this mean? Two important things it means is that they have spatial parts and that they have spatial location. Even physical bodies that might be too hard to actually cut nonetheless are conceivably divisible into spatially definable parts. A magically hard diamond that cannot be cut in half nonetheless has two spatially definable halves. This is what allows it to be, for instance, half in and half out of a box. Some substance dualists hold that, in contrast to physical bodies, it makes no sense at all to describe a mind as having spatial parts. Is your belief that the Eiffel Tower is in Paris in the left or right half of your mind? Is your sensation of pain in the top or the bottom half of your mind? Cartesian substance dualists reject such questions as nonsensical.
2.8
Of course, the belief is about something having a spatial location—it is, after all a belief about the Eiffel Tower's spatial location. But this undisputed fact concerning what the belief is about does not settle anything concerning where the belief itself is. And if you yourself aren't in Paris, what sense does it make to say that your belief about Paris is a belief spatially located in Paris?
2.9
Are things any different with a sensation of pain? If you injure your hand, don't you feel the pain in your hand? As many philosophers will point out, where we feel the pain to be (in a hand) does not settle the issue of where the sensation of pain itself is. A well-known phenomenon that occurs to amputees is that they will suffer phantom pains—it will feel as if they have an intense pain in a hand that was lost long ago (perhaps bitten off by a shark). So a pain can be felt in a hand that no longer exists (the shark digested it).
2.10
Of course, many physicalists will resist this dualist line of thought about spatial parts and spatial locations. They may hold that even though it is not apparent where your belief or sensation is, nonetheless, in reality, it does have a spatial location, perhaps in the cerebral cortex of your brain. We will have much more to say about physicalists in later chapters.
2.11
The second alleged contrast between mental and physical substances is another that we can trace back to Descartes. He holds that minds are thinking things and that physical objects are unthinking things. Thinking is a rational process or activity. It is the process or activity of reasoning. Descartes holds that only mental substances are capable of performing this activity or undergoing this process. According to Descartes, only a mental substance can be a thinking thing. In contrast, every physical object, no matter how fancy or complicated, is necessarily an unthinking thing. Of course, as we'll discuss in chapters 6 and 7, many proponents of neuroscience and artificial intelligence disagree with such a view.
2.12
A third alleged contrast between mental and physical substances has to do with the way that, when we think, we think about things. This property of “aboutness,” also known as intentionality, is held by some dualists to be a property that only nonphysical things can have. Intentionality is a very unusual phenomenon. On the face of it, it appears to be a sort of relation—you think about things. You think about the Eiffel Tower, and this looks to be a relation between you and the Eiffel Tower. However, if thinking about is a relation, it looks to be a very strange relation. One sort of thing we seem to be able to think about are things that are so far away that not even light can have made the journey between us and those things. We can also think about things in the far future and the distant past. Perhaps strangest of all is our ability to think about things that do not even exist, things that happen not to exist, such as a 20-foot dog, and things that couldn't possibly exist, such as four-sided triangles. Given how strange intentionality is, it is difficult to see how something that's purely physical, like a brain, can have it and thereby be related to things that don't exist in space and time.
2.13
A fourth alleged contrast between mental substances and physical substances is that only mental substances can bear properties that are “phenomenal.” What are phenomenal properties? We can get an especially strong feel for phenomenal properties when we attend to the qualities of conscious sensory experiences, such as the painfulness of stubbing a toe and the tanginess of biting into a lemon. There is something it is like to be a conscious human being biting into a lemon. The tanginess of the sensation seems not to be a property of the lemon itself—the lemon doesn't taste itself. The tanginess doesn't even need the lemon to exist, since we can have hallucinatory taste sensations. Similarly, as mentioned in connection with phantom limbs, we can have hallucinatory pain sensations. Where do such phenomenal properties reside? A substance dualist offers that such properties cannot reside in merely physical objects.
2.14
A fifth alleged contrast between mental and physical substances is a difference in how they are known. Physical bodies seem to be known via the senses. However, the senses can be deceived, and, thus, sometimes something that seems to exist really doesn't. If it is possible that you are wrong in believing something, then you can't be sure that you're right. Even if you are right, granting the mere possibility that you might be wrong means that you don't know that you're right with absolute certainty.
2.15
Arguably, while you can be wrong about the existence of physical objects, you can't be wrong about the existence of your own mind. If you think that you are thinking, you are guaranteed to be correct. And if you are thinking, then your mind must exist. According to this line of thought, your mind is known with certainty to exist even though no physical object is known with certainty to exist.
2.16
Now that we have examined the five alleged differences between minds and bodies, we can return to the discussion of Leibniz's law. We can take any one of the five differences, combine it with Leibniz's law, and create an argument for substance dualism. Take, for example, the distinction having to do with spatial parts and spatial locations. A substance dualist can argue that bodies, but not minds, have spatial properties, and thus a mind must be distinct from every physical body.
2.17
Consider another Leibniz's law argument for substance dualism. Recall the claim that minds but not bodies have the special epistemological feature of being known for certain to exist. Arguably, one knows for certain that one's mind exists, but one does not know for certain that any physical bodies exist. Perhaps you know of their existence, but not with absolute certainty. So the mind has the property of being known with certainty to exist, while every physical body lacks that property. It would seem to follow by Leibniz's law that the mind must be distinct from every physical body.
Criticism of Leibniz's law arguments: Intensional fallacy
2.18
The problem of the intensional fallacy arises for certain uses of Leibniz's law. Some Leibniz's law arguments for dualism commit this fallacy. Recall, for instance, a version of a Leibniz's law argument that goes like this:
We can state the argument in a way that makes the appeal to Leibniz's law even more apparent:
2.19
So, what is the problem with this sort of argument? What is the problem that we are calling the intensional fallacy? This problem can be spelled out in terms of the following analogy:
2.20
Recall the story about the comic-book superhero, Superman. As anyone who has read a Superman comic book or seen a Superman movie knows, Superman and Clark Kent are one and the same person. However, as all fans of these stories know, the character Lois Lane doesn't know that Clark Kent and Superman are one and the same. Consider the following bad argument about Superman, an argument that abuses Leibniz's Law:
Why is the above argument an abuse of Leibniz's law? In order for Leibniz's law to be used correctly, the relevant properties have to be properties of the things we are seeking to identify or distinguish. However, what Lois believes about Superman isn't really a property of Superman. She can believe he is a great guy and later change her mind and believe that he is a jerk without anything thereby changing in Superman. Similarly, Lois's belief that Clark isn't bulletproof isn't a property of Clark.
2.21
This bad form of reasoning is known as the intensional fallacy
