Physicalism

Daniel Stoljar

• Publisher: Routledge
• Year: 2010
• Print ISBN: 9780415452625
• eBook ISBN: 9781135149215
• Topic: Philosophy
• Subtopic: Philosophical Metaphysics

Physicalism, the thesis that everything is physical, is one of the most controversial problems in philosophy. Its adherents argue that there is no more important doctrine in philosophy, whilst its opponents claim that its role is greatly exaggerated. In this superb introduction to the problem Daniel Stoljar focuses on three fundamental questions: the interpretation, truth and philosophical significance of physicalism. In answering these questions he covers the following key topics:

• a brief history of physicalism and its definitions
• what a physical property is and how physicalism meets challenges from empirical sciences
• 'Hempel's dilemma' and the relationship between physicalism and physics
• physicalism and key debates in metaphysics and philosophy of mind, such as supervenience, identity and conceivability
• physicalism and causality.

Additional features include chapter summaries, annotated further reading and a glossary of technical terms, making Physicalism ideal for those coming to the problem for the first time.

1
THE STANDARD PICTURE

1.1 Introduction

There is a view about physicalism and its place in philosophy that is accepted by enough contemporary philosophers to be called ‘the standard picture.’ To put it very roughly, the standard picture is as follows.

On the one hand, physicalism is a thesis about the nature of the world that we have considerable and perhaps even overwhelming reason to believe. Physicalism is not an a priori doctrine, like a doctrine in ethics or mathematics. People who deny it are not thereby making any conceptual or logical error. Rather the status of physicalism is more like the status of the theory of evolution or of continental drift; in the words of Hartry Field, one prominent physicalist, “it functions as a high-level empirical hypothesis, a hypothesis that no small number of experiments can force us to give up” (1972: 357). Those who deny physicalism are not making a conceptual mistake, but they are, nevertheless, flying in the face not merely of science but also of scientifically informed common sense.

On the other hand, while physicalism is a thesis we have overwhelming reason to believe, believing it without qualification is no easy matter. For physicalism is on the face of it incompatible with, or at least is in some tension with, various claims that are central to ordinary or common sense views about humans and what they are like, views which in various ways are presumed also in the sciences. Some of the claims which physicalism might be thought to be inconsistent with or in tension with are:

• that people perceive things and have bodily sensations of various kinds, e.g. tastes, cramps, itches, nausea;

• that people speak and think about the world and about each other;

• that at least some words have meaning;

• that people’s bodies, and physical objects in general, are colored, textured, have various tastes, and emit sounds and smells;

• that people’s bodies, and physical objects in general, are solid or have bulk or fill in space;

• that people have reasons for thinking and acting as they do, and that those reasons may be subjected to normative (including moral) scrutiny;

• that people sometimes act and think freely;

• that people participate in group decisions and actions, and in turn the actions of these groups impact on the individuals who constitute them;

• that there are mathematical and logical truths (e.g. “5 + 7 = 12”), and that people can come to know these mathematical and logical truths.

In order to appreciate the importance of these claims, try to think for a moment how things would be if they were false—that nobody thinks or feels, or says anything meaningful, or that ordinary physical objects are not solid or colored, or that there is no freedom of action or social agency or mathematical knowledge. It is obvious when you think about it that these claims and others like them are central to life as we live it; they are, as I will say, the presuppositions of everyday life. So in effect what we are being asked to accept by the standard picture is the idea that there is a prima facie conflict between the presuppositions of everyday life on the one hand, and a thesis we have overwhelming reason to believe—i.e. physicalism—on the other.

In view of the conflict or apparent conflict between physicalism and the presuppositions of everyday life, we are faced with a number of options. One is to abandon or modify physicalism. But that seems implausible if physicalism really is, as proponents of the standard picture say it is, a thesis for which we have considerable evidence. Another is to abandon some or all of these presuppositions. But that too seems implausible. Even if we wanted to deny these claims, it is not clear that we could do so. (If a philosophy professor convinces you in a seminar that nobody is in pain and that no physical object is solid, you will forget both the moment you stub your toe on the doorframe as you leave the room.) The third option is to compromise, i.e. to propose ways to understand these presuppositions so as they are not incompatible with the truth of physicalism.

It is the third option that is most central to the standard picture. Indeed, it is no exaggeration to say that variations on this third option together make up large parts of what analytic philosophy is about. Large parts of analytic philosophy, that is, involve proposing and assessing ways of interpreting the presuppositions of everyday life so as they are compatible with the truth of physicalism. Famous philosophers are often associated with particular proposals about how to do this. For example, Gilbert Ryle in The Concept of Mind (1949) is famous for saying that psychological claims are logically in a different category from other kinds of claim, and that if that is true, the conflict between physicalism and psychological claims is merely apparent. Similarly, J.J.C. Smart’s paper ‘Sensations and brain processes’ (1959) is famous for saying that we might exploit Frege’s distinction between the sense of an expression and its referent in order to remove the source of tension between ordinary talk about mental states such as sensations and physicalism. Finally, Kripke’s (1980) discussion in Naming and Necessity of the necessary a posteriori looks like it is interesting in part at least because it permits us to say that physicalism makes the presuppositions of everyday life true without committing ourselves to various proposals about how these claims are to be interpreted and analyzed. As David Lewis once remarked, Kripke’s discovery of the necessary a posteriori looks from this point of view like a “godsend” (Lewis 2002: 95).

1.2 The generality of physicalism

The standard picture does not view physicalism as true merely for selected bits of the world—merely for human or sentient or living beings, for example. Rather it is intended be a very general and abstract doctrine that is true of the world as a whole. It is, as we saw in the introduction, a world-view or Weltanschauung.

One way to bring this out is to think of the world as a huge complicated structure, emanating out in various dimensions from the point at which you exist. There is the history of the world: human history both recorded and unrecorded; the history of living organisms, the history of the planet, the solar system and the universe itself. There is the future of the world (assuming the future exists) both for you, and for the universe in general. There is the composition of the world: almost any part of it is made up of smaller and smaller parts: your body, the organs of your body, the cells that make up the organs, the molecules that make up the cells; and so on. Correlatively, almost any part of the world forms larger and larger wholes: your family, your country, your species, the environment, and so on. Still other dimensions of the world are harder to capture in spatial or temporal terms. Every part of the world has various characteristic features and patterns of development. You in particular have various capacities to grow and decay, and to reproduce; you have various sensory and cognitive faculties and potentialities, some of which can be broken down into smaller faculties, and some of which constitute larger ones; there are various social and physical forces operating on you, and in turn you are an actor in a social and physical environment; you are subject to, and critic of, moral, aesthetic, prudential, and epistemic pressures of various kinds; and so on.

Physicalism has something to say about every aspect of this complicated structure. It says that everything here is physical, or to put it more cautiously (for reasons we will examine in the next chapter) that everything here is necessitated by the physical. It is this very general idea that, according to the standard picture, we have considerable and perhaps overwhelming reason to believe. But it is also this very general idea that, according to the standard picture, is inconsistent with, or in tension with, the presuppositions of everyday life.

1.3 Physicalism and the mind–body problem

Physicalism is a general thesis, but it is also very closely associated with the mind–body problem; indeed, the work of the three philosophers I mentioned a moment ago—Ryle, Smart and Kripke—was in each case a contribution to (among other things) the mind–body problem. This connection to the mind–body problem is important for the standard picture in two respects; first, it provides perhaps the clearest example of the general tension between physicalism and the presuppositions of everyday life; second, it provides a template for how to think about many other philosophical problems.

We will turn to this second issue—the way in which the mind–body problem provides a template for others—more fully as we proceed. But, first, how is the mind–body problem an instance of the general tension? Well, you might naturally think that the mind–body problem is a problem about the relation between two things, the mind, and the body. In fact in contemporary philosophy of mind, the problem is almost always conceived of as a problem about the apparent incompatibility of physicalism, on the one hand, and the existence and nature of various mental phenomena, on the other. If physicalism is true, humans and other sentient creatures are themselves wholly physical. But many philosophers think that there are arguments which if successful would show that the apparent fact that we sometimes have (e.g.) sensations is incompatible with the claim that we are wholly physical. (These arguments are usually called conceivability or modal arguments. I will set out these arguments in Chapter 10.) Since it seems obvious that we do have sensations—when we stub our toes, for example—the soundness of these arguments entails that physicalism is false. But as I have said, physicalism is something that, according to the standard picture, we have overwhelming reason to believe. So the mind–body problem in contemporary philosophy presents a sort of paradox in our thinking: apparently persuasive arguments like the conceivability argument show that two things we strongly believe cannot both be true.

If we have an apparently persuasive argument showing that two things we believe cannot both be true we must give up something—but what? Well, to abandon or modify physicalism is in the philosophy of mind case to become a dualist. Dualism may be developed in various ways, as we will see in the next chapter. But however it is developed, a dualist is someone who says that physicalism is at best mostly true, rather than being true outright. Maybe physicalism is true of most of the complicated structure I mentioned in the previous section—maybe it is true of rocks and planets and plants—but it is not true of people and other sentient creatures. The option of giving up the presuppositions of everyday life is in philosophy of mind called eliminativism. The eliminativist holds that since physicalism is true, and since physicalism is incompatible with sensations, then sensations do not exist. Finally, just as it does in the general case, the compromise option occupies most of the attention of philosophers of mind. There are two broad strategies here. One is to work out an account of what sensations are which makes it clear that the existence of sensations is compatible with physicalism. (Ryle, for example, is often interpreted as proposing a so-called behaviorist analysis of sensations according to which to have a sensation is to exhibit a certain characteristic pattern of behavior; Smart, on the other hand, is often interpreted as proposing a functionalist or topic-neutral analysis according to which to have a sensation is to have an inner state that plays a certain causal role, i.e. is caused by certain things, and in turn causes certain behavior and other mental states of a distinctive sort.) The other strategy, which is inspired by part of Kripke’s discussion (though was not endorsed by Kripke himself), is to argue directly that the conceivability argument is not persuasive, even in the absence of any functionalist or behaviorist analysis of sensations. As we will see in Chapter 10, it is most often this second sort of strategy that philosophers of mind have employed in recent discussions.

1.4 Philosophy within science

We have so far seen that, according to the standard picture, physicalism is a thesis we have overwhelming reason to endorse but is also in tension with the presuppositions of everyday life. We have also noted the generality of physicalism and its connection to the mind–body problem. But why did the standard picture become the standard picture? What is attractive about it?

One reason is that it solves, at least in part, the problem I will call—somewhat grandly—‘the problem of philosophy.’ Richard Rorty gives a vivid statement of this problem in the following terms:

If philosophy becomes too naturalistic, hard-nosed positive disciplines will nudge it aside; if it becomes too historicist, then intellectual history, literary criticism and similar soft spots in the ‘humanities’ will swallow it up. (Rorty 1979: 168)

Rorty might be read in this passage as if he were saying that the problem of philosophy were one about social power, i.e. about whether philosophy construed as a discipline will survive a competition with other disciplines to attract funding from a dean or a rich benefactor. But to my mind the problem is mainly an intellectual one about the very nature of philosophical problems. If philosophical problems are at bottom scientific ones, they seem not to be the sort of thing that philosophers, with their special talents and training, can study. On the other hand, if they are at bottom unscientific ones, then it seems most likely that they should be grouped together with problems about the historical development and cultural expression of ideas; that is, the sorts of problems discussed mainly in history or literature departments rather than in philosophy departments. What then could philosophy possibly be about?

This dilemma has been close to the heart of a lot of philosophy at least since the onset of logical positivism in the 1930s and perhaps much earlier. How to solve it? Well, one option is not to solve it but to embrace it; that is, give up on philosophy and become either a scientist or a person of letters—to become (or try to become!) either Einstein or Nietzsche, as it is sometimes put. If one wants to defend philosophy against this dilemma, however, it is necessary to find something for it to do that is neither science nor literature. The standard picture we have been discussing provides an apparently simple and decisive answer to the problem. Physicalism is a thesis about the world that, on the face of it, has impeccable scientific credentials. But physicalism also looks to be in conflict with the presuppositions of everyday life. In the light of this conflict, we seem inevitably to face the intellectual project of resolving it. Such a project seems important, since we can give up neither physicalism nor everyday life, and yet it is not in any straightforward way either scientific or literary. In summary, physicalism solves (in part, at least) the problem of philosophy.

We may put the basic point differently by connecting the problem of philosophy with the idea of a placement problem, and related to this, with the idea of a Weltanschauung, both of which I mentioned in the introduction. As Freud says in the passage I quoted, a Weltanschauung is a relatively simple thesis or proposal that applies to everything; we may think of it as a relatively simple thesis about the world that aspires to completeness, i.e. tha...

Table of contents

• New Problems of Philosophy
• CONTENTS
• ACKNOWLEDGMENTS
• INTRODUCTION
• 1 THE STANDARD PICTURE
• 2 FORM AND ALTERNATIVES
• 3 THE STARTING POINT VIEW
• 4 THE THEORY VIEW
• 5 HEMPEL’S DILEMMA
• 6 THE NECESSITY VIEW
• 7 IS NECESSITATION NECESSARY?
• 8 IS NECESSITATION SUFFICIENT?
• 9 SKEPTICS AND TRUE BELIEVERS
• 10 ARGUMENTS AGAINST PHYSICALISM
• 11 ARGUMENTS FOR PHYSICALISM
• CONCLUSION
• GLOSSARY
• REFERENCES
• INDEX