Introduction

Over the past 2500 years there have been many responses to the mind/body problem. The readings in this section represent a chronological sketch of the movement between four of the most influential general proposals: dualism, materialism, idealism, and func­tionalism.

Although the claim is hotly debated among contemporary philosophers and clas­sicists, Aristotle may be thought of as the first functionalist. In his discussion of definition—which he takes to express the formula, or essence, of a thing—Aristotle describes objects as combinations of form and matter. According to Aristotle, there are many cases where the form of the object is essential to the object, while the matter is not. For example, a word written in wax contains its letters as part of its formula but is only coincidentally made of wax (since it could equally well be engraved in stone, written on paper, etc.). Because the form of a word like “dog” can be realized in many different substances, we know that the form and the material substance are not identical.

Thomas Hobbes provides an early and influential statement of identity theory in his account of perception: visual experiences are really only the action of external physical objects on our physical organs.

Rene Descartes provides the classical statement of dualism. Starting with the ex­perience of his own mental existence, Descartes asks whether the idea of his mental existence is indistinguishable from the idea of his body. His answer is that it is not, concluding that the idea or essence of mind is different from the idea of body. Since two things that correspond to different ideas cannot be identical, the mind must be different from the body.

George Berkeley argues that a thorough empiricist will be led to adopt idealism. According to Berkeley, if all our knowledge comes to us through sense impressions,

4 Part I Introduction

then we can never have knowledge of material substance itself. We may posit material substance as the cause of these impressions, but there is no direct evidence for such substance, and positing such substance may lead us into contradiction. His conclusion is that there are only minds and sense impressions.

John Stuart Mill introduces a new concern into the debate. Mill agrees that material­ism is a plausible answer to the ontological question about the mind (the question of what the mind really is), but argues that we should not overlook the methodological question of how science should proceed to study the mind. Even if we hold that mental states are brain states, the brain is so complex and so poorly understood that we must study mental regularities independent of brain research.

Gilbert Ryle, who is a logical behaviorist, provides an influential criticism of dualism. According to Ryle, dualists are guilty of a category mistake. For example, it is perfectly legitimate to talk about a football team winning a game, and it is also legitimate to talk about the individual members of a football team, but it would surely be a blunder to think that the team is something that exists in addition to the members of the team. For example, if someone were introduced to the members of the team and then ex­claimed, "Now Γd like to meet the team," we would say that the person was fundamen­tally confused. Talk of the team is really just talk of the members of the team at a certain level of abstraction. Likewise, according to Ryle, we can talk about mental states (like pain) and we can talk of certain behaviors (like holding damaged body parts and moaning), but it would be a mistake to suppose that the mental state of pain exists in addition to some relevant class of behavior.

U. T. Place attempts to defuse certain arguments against the identity theory. Place argues that two things can him out to be identical even if their definitions are different: "lightning", for example, doesn't mean the same thing as "electrical discharge", but we can discover that lightning and electrical discharge are identical. Likewise, though "mind" and "body" may have different definitions, we can nonetheless discover that mind and body are identical.

The selection from Saul Kripke presents a broadly Cartesian response in support of dualism. According to Kripke, science discovers essences. So, when we discover that lightning is electrical discharge, we discover that the essence of lightning is that of electrical discharge. Alternatively, if the essence of lightning and electrical discharge should turn out to be distinct, then lightning and electrical discharge would amount to distinct things.

Noam Chomsky sketches a radical approach to materialism. According to Chomsky, the notion of body is itself subject to revision by the sciences. For example, the concept of body employed by Descartes was soon superseded by the Newtonian notion of body, and research in particle physics during the last century has continually revised our understanding of the nature of physical bodies. This being the case, Chomsky argues that the very notion of the mind/body problem is ill defined. It is ill defined because we have no clear conception of what the body is. Moreover, he suggests that if our understanding of mental phenomena seems incompatible with our understanding of the physical body, then our understanding of the physical body will have to change to accommodate the mental. Our ultimate understanding of body will be shaped by (among other things) our theories of the mental.

Hilary Putnam initiates the contemporary discussion of functionalism. Like Aristotle, Putnam is concerned with the formula of the soul, though he suggests in "The Nature of

The Mind/Body Problem 5

Our Mental States" that it can be thought of as a Turing machine, an abstract computing machine. Turing machines can be instantiated in many different kinds of hardware— silicon chips, Tinkertoy models, and, according to Putnam, the human body. Putnam argues against the identity theory by using a multiple instantiation argument: because a given psychological state (e.g., pain) can be realized in creatures with nervous systems quite different from our own, and indeed can presumably even be realized by the silicon-based creatures of science fiction, there is no single physical type that correlates with the psychological type pain. Consequently, no reduction of the psychological state pain to a single type of neurophysiological state is possible.

Patrida Churchland is unimpressed by this use of the multiple instantiation argu­ment. She argues that Putnam's notion of reduction is far too restrictive—so restrictive that by Putnam's standards it is not clear that any science has been successfully reduced to a more fundamental science. Take, for example, the theory of thermodynamics, which is widely taken to have been reduced to statistical mechanics. As Churchland notes, a kind of multiple instantiation argument is possible here as well, for in gases, heat is reduced to mean kinetic energy, in solids something else, and in a vacuum something else again. But we don't conclude that there is no reduction.

Ned Block attacks functionalism from another direction, arguing that any functional definition of mental states will be either too liberal (ascribing mental states to creatures that don't really have them), or too chauvinistic (failing to ascribe mental states to creatures that do have them). In setting up his argument, he surveys a number of concerns that have been raised against functionalism, including the problem of account­ing for the phenomenology of mental states. Block's article is also useful in providing an extensive classification of the various types of functionalism.

In 'Thilosophy and our Mental Life," Putnam criticizes his earlier formulation of functionalism, arguing that the multiple instantiation argument can also be extended to Turing machines—thus showing that mental states cannot be reduced to Turing ma­chine states. But Putnam does not reject functionalism. Rather, he defines functional states more broadly as classes of structurally identical states, perhaps returning to something a bit more like Aristotle's notion of "form."

Further Reading

Several good collections are available on the mind/body problem, though they are primarily concerned with the debate between materialism and dualism. They include:

Borst, C V., ed. 1970. The Mind/Brain Identity Theory. London: MacMillan.

Presley, C F., ed. 1967. The Identity Theory of Mind. University of Queensland Press.

RosenthaL David, ed. 1971. Materialism and the Mind-Body Problem. Englewood Cliffs, NJ: Prentice Hall.

The following collections are more genera] but also address the mind/body problem. The Blodc and Lycan collections have particularly good sections on functionalism.

Block, Ned, ed. 1980. Readings in the Philosophy of Psychology ool. I. Cambridge, MA: Harvard University Press.

Hook, Sidney, ed. 1960. Dimensions of Mind. New York: Collier. Lycan, William, ed. 1990. Mind and Cognition: A Reader. Oxford: Basil Blackwell.