METAPHILOSOPHY Vol. 14, No. 1 , January 1983

REVIEW

STEPHEN N. THOMAS, The fomal mechanics of mind Ithaca, NY: Cornell University Press, 1978,325 pp.

Recent philosophy of mind might usefully be described as a succession of battles between the Wittgensteinians arguing that scientific models cannot ultimately describe our distinctively human features, and those who think that a science of psychology is possible. While Anscombe, Kenny and Dreyfus point out the limits of causal explanations of human action, cognitive psychol- ogists, materialists and such philosophers as Putnam and Dennett argue that models of mind derived from artificial intelligence research are illuminating. Thomas is of the latter group. He claims that mental states are describable by a functional state table (FST). A FST specifies how what someone does in any given situation (the “output”) is a function of their internal states and the “input”, “the external stimulation or object” (p. 68) affecting their sense organs. The FST describing something doesn’t tell how that thing is arranged inside. Typewriters constructed very differently satisfy the description: “pressing the ‘a’ key produces a printed‘a’ ”.

This theory, Thomas argues, correctly characterizes our mental states. Wittgenstein was right to argue that mental states are not “private sense data” (p. 93), but wrong to deny that talking about one’s own mental states is to describe them. To say “my foot hurts” in response to a question about why I grimace is to produce a description of my mental state because I am in a certain internal state. Descriptions of mental states stand to the body as the FST of a typewriter stands to that machine. This does not commit us, he argues, to saying either that mental states are identical with the internal states described in the FST or that mental states are any particular kind of thing. The same FST could describe the states of a Cartesian soul and the physical states of a neural network. We need not know what is inside a black box to produce the FST describing it. Thomas calls his theory a form of behaviorism. This could be confusing if we think of a behaviorist as someone like Skinner who denies the existence of “inner” mental states. Actually, Thomas’s model of the mind is much like that of cognitive psychology. Thus, in Sciences of the ArtificiaZ Herbert Simon argues that computer models are useful because what psychology should study is how we respond to stimuli, not the physical organization of our brains. That a computer can model our behavior does not imply that we are constructed like the computer. But the parallel does show that our mental states and the computer’s states are described by the same FST, and that surely commits us to saying that mental states exist, even if they have no 1-1 relation to entries in the FST.

Thomas applies his theory to various accounts of mental phenomena.

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REVIEWS 73 Some - Anscombe’s analysis of action, Fodor’s psycholinguistics - are familiar to philosophers, while others - descriptions of spectacles inverting the visual field and an apparatus providing “sight” for the blind by translating visual information into tactile sensations - are novel. And Thomas argues that if his account is correct, Quine’s thesis about indeterminacy of trans- lation is false. Indeterminacy of translation would require that there be two incompatible FST’s describing the same behavior, and that is impossible.

Consider three general problems with this theory. How is it possible to describe ordinary behavior in terms of “inputs” and “outputs”? If I am participating in a test of color identifications, I say “yellow” when I see a banana. But outside the laboratory how I respond to a banana is more compli- cated. I might say “it’s yellow”, or “it comes from Central America”; I might pretend to cower as if it were a gun; I may eat it. Thomas notes these compli- cations (pp. 149-55). We need, he says, “a theory of perception” (p. 155). But the difficulty is not just that my response is related in complicated ways to what I see but that what I see may need to be described in terms of how I respond. Speaking of an “input” suggests, misleadingly, that what I perceive can be described independently of that response.

Furthermore, how do I understand such a FST when it is the FST describ- ing me? Thomas speaks of showing “how a person’s total present conscious awareness . . . can be the FST - determined macrolevel outcome of a large number of microlevel processes . . .” (p. 305). I can tell how various “inputs” affect me. Hearing Schumann makes me feel nostalgic; Mozart played by Could, anxious; and Bruckner, nauseous. But can I imagine that I am the realization of a FST? Given a diagram of my FST, can’t I simply choose not to act in accordance with that FST? For this FST contains predictions about my behavior, and in many cases falsifying those predictions seems within my power.

Is the FST model really a theory of mind, what Thomas calls a “concep- tualizing structure” (pp. 2 8 1 4 ) ? If a theory of mind must tell us what kinds of things mental states are, i.e., whether they are states of an immaterial or a material structure, then Thomas’s theory is not helpful. Such functional theories, Herbert Simon has suggested in discussion, are perhaps less than fully scientific. (Though Simon might not now, on reflection, accept his own earlier argument, it seems worth discussion, I think.) Consider the simple FST for a pocket calculator. Pressing the button labeled “2”, the “+” sign, and “3”, I get the output, “5”. But the FST tells me only how this calculator happens to be wired. I have learned nothing about the theories of physics which are needed to explain how calculators work.

These arguments I have so briefly sketched are certainly not decisive. But the trouble with The Formal Mechanics of Mind is that it doesn’t give clear suggestions about how such obvious questions are to be handled. And given its length, this seems a large defect. A reader would be less likely to balk at following such long and technical analyses were the overall plot of the book clearer. The book would be easier to understand, I think, if Thomas compared

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his account with the familiar work of Kenny, Dennett and Davidson. And, since he does frequently refer to Putnam’s papers on Turing machines, refer- ence to Putnam’s retraction of some of his own earlier claims - in hisMind, Language and Reality, published in 1975 - would seem appropriate.

Thomas criticizes Wittgenstein’s attempt to eliminate explanations from philosophy. He says that the explanation/description distinction is not clear because, for instance, it isn’t clear whether Copernicus’s account is an expla- nation or a description (p. 22). Wittgenstein’s use of examples in the Philo- sophical Investigations follows, I would argue, the procedure outlined in the Tractatus, 6.53. The reader who “gets” the examples, who “sees” what Wittgenstein doesn’t put into words, can discard those examples after under- standing them: No theory is needed. Certainly a review isn’t the place to argue for such a doubtlessly controversial interpretation. But Thomas’s droll claims that putting yourself in the subject’s position is not what Wittgenstein would advocate (p. 57); that the language game’s rules can be represented by a FST - description (p. 231); or that Wittgenstein might speak “of a group of FST’s talking to one another” (p. 232) are, uncontroversially, mistaken read- ings of Wittgenstein. Thomas’s general characterization of his own account as a “Conceptual system”, like “the molecular theory of gases . . . French law . . . and the Christian ethic” (p. 282) does not locate that account in a happy way. The details of that account are often fascinating. These remarks about its place in philosophy are, to put it paradoxically, both too long and too short; too long because what Thomas says about Wittgenstein and the role of theories in philosophy is too elementary; too short because he doesn’t succeed in describing the exact status of his own theory. An unrepentant Wittgen- steinian might, I think, view Thomas’s account as an interesting psychological theory without rejecting Wittgenstein’s view of the relation between philos- ophy and science.

The form of Thomas’s presentation is frustrating. Elementary material such as the first chapter account of Wittgenstein is mixed with very technical arguments. To determine Thomas’s view of one topic the reader must some- times collect remarks scattered throughout the book. An important part of the discussion is relegated to the fourth appendix, and introduced only after a summary of material presented earlier. Since Thomas discusses questions which are important, and have been widely discussed recently, and since he offers an apparently novel approach to these questions, it is unfortunate that the presentation of his account is off-putting in these ways.

DAVID CARRIER CARNEGIE-MELLON UNIVERSITY PITTSBURGH, PA 1521 3