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neutral in what I called the fundamental dispute above. The book is, though never actually unfair to Chomsky's opponents, very much in the stream of thought on the Chomskian side: so that issues tend to be discussed as though Chomsky's disciples had raised them in the first place. This is not altogether historically correct: for it was the Generative Semanticists dissatis- faction with Chomskian orthodoxy that eventually ruptured the whole carapace of trans- formational grammar and led to a new school oflinguistic theory. It was certainly not Chomsky's conservative associates who set the pace for developments, as the tone of this book sometimes seems to suggest. On the other hand, what may turn out to be the case--and this cannot be known yet--is that the Chomsky disciples (or Interpretive Semanticists, as they are now known) may be the only ones left standing on the field at the end of the struggle. And that simply because, in denying Chomsky's central thesis that there can be a selbstdndig linguistics indepen- dent of logic, meaning, psychology etc., Generative Semantics may quite inadvertently have created a situation where, if they are right, there is no independent subject matter to defend. It is not clear to this reviewer, for example, that there is any longer a serious generative linguistics independent of AI. (Though others will reply, no doubt, that there may well be no AI independent of etc. etc.)

This book does cover all, or almost all, the complex issues that have been raised in these areas over the last ten or twelve years, and that is no mean feat. There are inevitable drawbacks: the discussion is often at the level of philosophical slogans, and this may well annoy sensitive readers. On page 15 we find "For what is characteristic of proper names is precisely that they have no meaning", which is one slogan among many about proper names, but not one that should get unique and uncritical endorsement in a university text.

Again, on pages 20-21, the Verification doctrine is dismissed too cheaply and rapidly. This is done in juxtaposition with a discussion of speech acts but without ever mentioning that verificationists have a clear, if wrong headed, notion of speech acts: namely, those statements which constitute their own verification when uttered (as in "I name this ship Libert6").

The book avoids any form of radical criticism of whole enterprises, and there is a lack of any critical works in the bibliography (Cohen is not mentioned in connexion with speech acts, for example, in spite of the influence of his critical article arguing that they have nothing to offer to linguistics). Whether or not this feature is acceptable, or even desirable, in a University text book, will depend very much on one's basic assumptions about how students should approach linguistics.

An odd stylistic feature of the book is what one might call the "no-owner argument": passages of argument are given without the reader being able to find out whose it is, there being no indi- cation that it is Ms Fodor's. In a philosophical work that would be quite normal, for the emphasis there is on the issues and arguments and not on who owns them. But in a book like this whose basic function is to attach arguments to owners, and which makes no claims to theoretical insights of any depth, that stylistic fault can be frustrating (a number of examples can be detected by the careful reader on pages 54--55).

But, by and large and within the limits it has set itself, the book will perform a useful function as a teaching introduction to a complex theoretical area. It has Chomsky's own imprimatur on the jacket, which will serve as a recommendation or warning according to taste. The book will certainly date fast, but in 1977 it has no rivals.

The reference (Lewis, 1972) is in the text (page 52) but not in the bibliography, and there is a misprint on page 51.

YORICK WILKS University of Essex

The Language of Thought By J. A. Fodor, 1976. Hassocks: Harvester Press. £10.00.

To someone, like myself, working in artificial intelligence, this book is at first delightful, on closer acquaintance irritating and finally, downright annoying. It is always pleasant to find someone arguing a strong and wittily presented case for a view whose truth seems to one to be self-evident. Fodor is concerned to defend the view that there is a language of thought, a representational system which the mind uses to think with: or, one should rather say, operations

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in which are the thoughts that the mind has. But, "of course", one feels: and many of Fodor ' s detailed points also have a satisfying ring to our ears, for example, his rejection of neurological reductionism, or his use of the mind-software, brain-hardware analogy. But, as Fodor says, the best way to show that speculative psychology is possible is to actually do some: and this is exactly what AI and information processing psychology has been doing for over ten years now. Fodor nowhere refers to this work, even though he complains (page 33), that cognitive psycholo- gists have paid almost no attention to representational issues. (GPS and Young's work on sedation are the only exceptions: the names of McCarthy, Minsky, Papert, Schank, Winograd, for example, are all absent from the bibliography.) This is, to put it mildly, a pity. Many of Fodor ' s detailed points could have been well illustrated by reference to this literature, and he would have been saved from a naivety in his use of the mind-software analogy which mars some otherwise pretty arguments.

Fodor is making a philosophical point. His main protagonists are Skinner, Ryle and Wittgenstein. He is concerned more to establish that there must be a language of thought, and that one might in principle investigate it empirically, than to actually investigate it himself.

His main argument can be found conveniently summarized on page 27. Somewhat abbrevi- ated, it runs thus.

(1) The only plausible models of cognition which we have are computational ones. (2) Computation presupposes a representational medium or language. (5) What is this language like? Is it a reasonable research goal. (6) Maybe we can find out something about it by looking at the details of current psycho-

logical theories. (7) The prognosis is hopeful.

The first chapter gets behaviourism and brain theory out of the way. Ryle is taken to. be the apostle of the former, and he gets short shrift. Brain theory is more difficult. Clearly, psycho- logical events can be correlated with physical events in the brain. Fodor argues, however, that this is not a reduction of psychology to physiology since several events with the same psycho- logical description (say, thinking it is going to rain, or being very happy) will correlate to brain states which have no physically (neurologically) describable common features, or at any rate not enough to identify them as falling under some identifiable category in the neurological science. That is, psychological laws will not be consequences of neurological laws (contrast the relationship of chemistry to physics) since psychologically significant features of an organ- ismic state simply will not uniformly reduce, Fodor argues, to physically significant features.

The second chapter states the main argument and develops it in several areas. Here is a sample: consider concept learning. People find it easier to learn a concept when it is expressed as A & B than when it is expressed as--] ( - ]A or-]B): but these have the same extension. It must be that the form of the representation of the concept is of significance in people's cognitive processing: a fortiori, they must represent the concept somehow, i.e. there most be a language of thought. He also discusses empiricist theories of perception here: again, some reference to the history of machine visual perception work would have been useful (one can clearly see, in the history, the rejection for solid engineering reasons of the sense-data paradigm).

The next chapter develops the point that the inner representational system must actually be a language--but not a natural language. It must be a language because, since we can learn a natural language, it must be possible to express the concepts expressible in, say, English, in the inner language (or at least their extensions, anyway). For what is it to learn an English- expressed concept other than to be able to express it in the inner language, and use that expres- sion appropriately in thinking? Now, the inner language cannot be a natural language since it is not acquired (i.e. we do not think in English): and anyway, animals can think yet do not speak. So it must be innate. Fodor is thus brought to the position that we are born possessing a very rich conceptual language (i.e. at least sufficiently expressive to encompass all concepts expres- sible in natural languages). In a later chapter he levels much criticism at the Plaget-Bruner idea of stages of development, using an exactly similar argument.

His defense against a charge of circularity is this appeal to innateness. He draws an analogy to a high-level programming language: understanding a sentence of English is like compiling a high-level program into a machine code program. The relationship of the ALGOL program

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to the machine involves translation, but the relationship of the machine code program to the machine does not. The machine just is constructed so that it directly obeys the machine code. So, Fodor argues, we must have a similarly direct relationship to our language of thought. It must be our machine code: our grains (considered as neuronal machines) must just work in such a way that when the representation (in the code) of a thought is loaded, as it were (i.e. we think the concept), then the representations of the rational consequences of that thought are generated by the brain. Notice the word "rat ional" here: Fodor assumes that cognitive psychol- ogy must be concerned with rational thought: irrational thoughts, such as obsessively thinking of Monica Vitti (his example) may have to be excluded from the subject matter of the science, unless, pace Freud, they can be assimilated as unexpected by-products of some unconscious rationality.

The rest of the book is an attempt to interpret some current linguistic and psychological results of providing information about the structure of this machine code. Very briefly, there seem to be three main issues covered.

(1) Transformational grammar currently has some bother with sentences like

Only Fred pities himself and Only Fred pities Fred

which are not synonomous, but of which the first can be derived transformationally from the second. Fodor reviews how to rescue the situation, and infers, from the deep structures he has to posit, that the brain's machine code must be able to encode a notion of "self", but that as far as these examples are concerned, there is no reason to suppose that it needs variables or quantifiers.

(2) In understanding English (say), do we use definitions or not? Does, for example, "bachelor" have the same internal-code representation as "unmarried man", or not? Fodor decides not, on the following grounds: comprehension is fast, while inference might not be. Ergo, a theory which makes comprehension simple and inference complicated is to be preferred. So, we should prefer the theory that to comprehend "bachelor" is to assign its code, similarly for "unmarried man", and to know their synonymity is to infer (code for "bachelor")--(code for "unmarried man") in the logic. The argument is nicely summarized on page 154.

(3) Does the internal code use images or descriptions? This is a hoary issue, and Fodor does not throw a great deal more light upon it. He does take some issue with Dennet 's famous argu- ment about the tiger's stripes (if your imagining of a tiger is a picture it must have exactly n stripes for some integer n. Imagine a tiger! Got it? Now, what is n?), his basic argument being that the image might be too fuzzy to enable you to count the stripes.

As I began, basically, a delightful book, and a pleasure to read. But Fodor used the computer metaphor so crudely and so loosely. The central analogy between understanding and compila- tion just will not stand up to close scrutiny. Compilation only makes sense, for example, for imperative languages, since machine codes consist of imperatives (I take it that, in the analogy, the compilation of English into the brain's machine code is supposed to preserve meaning). But most of English isn't imperative. Fodor 's account of the code's rational-inference structure is consistent with (for example) Winograd's account of meanings as programs which when run perform inferences, but this account of meaning now seems hopelessly limited. Fodor 's sharp distinction between comprehension and inference (surely, the former involves the latter), his discussion of imagery and various other of his arguments, seem much less convincing when viewed in more computational detail. It just isn't clear that there is any useful compu- tational distinction to be made between images and descriptions, for example: a possibility which Fodor does not seem to contemplate.

The worst oversimplification, I think, is involved in his arguments which appeal to processing speed, such as that on comprehension vs. inference sketched above. From the fact that a machine- program combination performs some task quickly, one can infer nothing about the nature of the computation unless one knows both what the algorithm of the program is (in more or less detail) and the power of the machine. Certainly the brain is an extremely powerful computer, if it is a computer at all. For such a machine to perform a very sophisticated computation in a quarter of a second is nothing remarkable. One certainly cannot rule out all algorithms other than a table look-up using a matcher.

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Philosophical battles may well ensue from this book, I hope they do, and I hope Fodor wins them: his heart is in the right place, after all. But if he wants to discuss computation, he should discuss computation.

PAT HAYES University of Essex