A defining light in the darkness of the mind

March 9, 2001

Keith Sutherland engages with a polemical consciousness raiser.

A few years ago, the Royal Society organised a short meeting on the "problem of consciousness" at its headquarters in London's Carlton House Terrace. Most of the speakers - including Jeffrey Gray from the Institute of Psychiatry and psychologists Max Velmans and Stevan Harnad - could be positioned on the "mysterian" wing of consciousness studies. Mysterians believe that there would still be "something missing" even after a complete description of brain states or the mental modules beloved by cognitive science.

Jerry Fodor, author of The Mind Doesn't Work That Way , could also be classified as a consciousness mysterian, but then so would be his opponent Steven Pinker, whose How the Mind Works is the target of this polemic. But, not content with one mystery, Fodor claims that the real mystery of psychology is how to extend the dominant computational model to account for the holistic properties of cognition ("abduction" to the cognoscenti and the artificial intelligentsia; "common sense" or "flexibility" to the rest of us).

Fodor acknowledges that artificial intelligence (AI) has been moderately successful in its attempts to model domain-specific cognitive processes. The dominant theory, which Fodor helped to establish, is the fusion of nativism (the mind as composed of a series of innate modules) and computationalism (thinking as essentially a syntactic operation on the local "database" that goes to make up the module under consideration). According to this theory, local mental processes are operations defined on syntactically structured mental representations that are much like sentences (the "language of thought"). The emphasis on syntax presupposes the primary assumption of rationalist psychology - that beliefs, desires, thoughts, and the like have logical forms and are thus amenable to computational modelling.

But hang on, says Fodor, the modularity/ computational assumption may be the sine qua non of classical artificial intelligence, but unfortunately the mind doesn't work that way. The computational theory of mind presupposes that syntactic mental processes are insensitive to context-dependent properties of mental representations, and this is plainly not the case. If thinking is a mechanical syntactic operation on a local database (informational encapsulation), how do we account for the properties of a thought "that are sensitive to which belief systems it's embedded in"? [Fodor's italics] Unfortunately (at least from the point of view of AI and computational modelling), human cognition is characterised by what philosophers call abductive (holistic) inference. Abductive reasoning is known in the jargon of AI as the "frames problem", and no one has figured out how to solve it. According to Fodor, Chicken Little was right all along - "abduction really is a terrible problem for cognitive science".

Some philosophers and scientists argue that the success of abductive reasoning is an illusion - all we have is local approximations to global processes, and perhaps the problem of calculating these approximations is solved heuristically, case by case. But Fodor dismisses this as a circular argument. The computational theory of mind cannot be patched up with quick heuristic fixes, as the inferences about which local heuristic to employ are themselves often abductive.

Fodor argues that the failure of classical AI, even with heuristic fixes, to produce successful simulations of routine common sense cognitive operations is "scandalous". He is even more dismissive of the claims of the new kid in town - connectionism - as a competing theory. Connectionist networks fail to provide either a plausible account of the causal consequences of logical form or of abductive inference. Here Fodor sounds off in the style of the recently deceased Auberon Waugh - connectionist networks are "simply hopeless - it must be the sheer magnitude of their incompetence that makes them so popular".

But Fodor is not a columnist, he is a philosopher, best known as one of the pioneers of the fusion of Turing's computational theory of mind with Chomskyan nativism. His books, The Language of Thought (1975) and The Modularity of Mind (1983), have been immensely influential and yet, in this book he argues that the really interesting aspects of human cognition are neither modular nor syntactic (or at least, in the latter case, possibly not). This leads him to claim that "so far, what our cognitive science has found out about the mind is mostly that we don't know how it works". He even refers to his 1983 book as adopting an "unhelpful policy". Is Fodor undergoing a Wittgensteinian epistème - will scholars end up discussing the early and the late Fodor, or are there other factors at work?

Although Fodor claims that this book is a light-hearted and polemical attack on the New Synthesis (the fusion of the computational theory of mind and the "massive modularity" thesis with a Darwinian theory of origins), he admits that he is "worried half to death" about the failure of classical cognitive science, and explains the "pervasive good cheer" of writers such as Pinker and Henry Plotkin with the aid of the psychoanalytic concepts of suppression and deep denial. Otherwise, how could Pinker admit that we are far from being able to build a serviceable robot, but claim that we know, more or less, how the cognitive mind works?

One of the reasons that the Faustian pact that constitutes cognitive science has been such a flop is that no one can even agree what the discipline is meant for (science or engineering?). The human and social sciences (psychology, anthropology, linguistics, neuroscience, philosophy, and so on) are interested in understanding how the mind works as an end in itself or to improve the human condition. But computer science and artificial intelligence are engineering disciplines - "AI was generally supposed to be about engineering, not about science; and certainly not about philosophy". Although Marvin Minsky and Aaron Sloman may like to think they are researching how the mind works, their paymasters (mostly in the military) are more interested in ensuring that the next generation of Cruise missiles hits Saddam Hussein's bunker rather than the hospital next door. Similar confusion might be imagined if we were to merge literary criticism and quantum physics (oops, Alan Sokal got there first).

An example of this confusion can be found in Fodor's repeated claim that Turing's principal contribution to cognitive science was his discovery that "thinking was syntactic". How and when did Turing make this "discovery"? Although it may have amused him to dream up parlour games between human subjects and robots, the bosses at Bletchley Park were more concerned with cracking the German Enigma codes. The electronic computer was invented for this purpose, and Turing machines, by definition, solve problems using only local syntactic processes. The technopomorphic projection of this architecture on to human subjects has been the prime cause of the confusion in cognitive science.

To return to our Royal Society meeting, Harnad's take-home message was that even if we are never likely to crack the problem of consciousness, there is still plenty of work left to do in cognitive science. Fodor endorses this, arguing that we should "plug on at the problems about the mind that we do know how to think about". Fair enough, but why then bother to write this book?

The answer, of course, is to deflate the "relentless cheerfulness" of the Pinkers of this world and to undermine the tedious and hubristic claims that we are about to conquer the "last frontiers of human understanding". According to Fodor, the main achievement of 40 years of cognitive science has been to "throw light on how much dark there is". Such refreshing outpourings of humility are few and far between, and this book should be on all Lent term reading lists for this reason alone. The other value of the book is that it shows philosophy is still an important discipline. No doubt, the proponents of classical AI and connectionism like to see their work judged on purely technical grounds. To Fodor, the arguments in AI reflect an epistemological dispute that goes back at least as far as Kant and Hume ("you can drop out for a couple of centuries and not miss a thing") and ultimately to Plato and Aristotle. Fodor nails his philosophical colours to the mast as an Enlightenment rationalist and describes the theories of his empiricist opponents as "appalling". His claim that bona fide abductive inferences are non-local, hence noncomputational, by definition parallels Roger Penrose's argument that human cognition involves a noncomputational element. Most people working in cognitive science dismiss Penrose as a deranged Platonist, "out of his microtubules", who should mind his own business (mathematical physics), but it is difficult to dismiss the Fodor polemic so easily as his is an attack from a respected scholar within the camp.

Fodor's other target is the growing arrogance and imperialism of neo-Darwinism and evolutionary psychology. To Fodor, drawing on Noam Chomsky's argument that the development of natural language cannot be accounted for by Darwinian processes, nativism does not necessarily imply adaptationism. Fodor describes the argument that cognitive nativism necessarily implies Darwinism as an indication of the politicisation of science. He claims that "some radical reorganisation of global cognitive structure" must have occurred in the process of getting from the minds of apes to Homo sapiens , and it is hard to see how this could be attributed to Darwinian processes. I do not know whether this will lead to premature rejoicing in the Bible Belt.

One final caveat to an otherwise enjoyable and informative read. MIT Press/Bradford Books became the leading publisher in cognitive science partly on account of exacting editorial standards. But this book does not appear to have been near a proof reader or copy editor. The style oscillates between the witty polemic of the broadsheet columnist and dense jargon. (The publishers have also decided that the book does not merit a proper index.) This is unfortunate, as it deserves to be read beyond the ivory towers of the philosophical community. The young Turks at Bradford Books have failed to live up to the high standards of the founders, the sadly missed Harry and Betty Stanton.

Keith Sutherland is executive editor, Journal of Consciousness Studies .

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