Metaphysics and Computational Cognitive Science: Let’s Not Let the Tail Wag the Dog

Volume 13
Issue 1
Frances Egan
David Chalmers characterizes the central commitments of computational cognitive science in terms of two theses: computational suf ficiency, the idea that the right kind of computational structure suffices for the possession of a mind, and computational explanation, the idea that computation provides a general framework for the explanation of cognitive processes and behavior. The computational program has been challenged by Hilary Putnam (1988) and John Searle (1991), who argue that every physical system implements every computation, with the consequence that any computational ‘explanation’ of cognition is utterly trivial. What is needed, according to Chalmers, is an account of implementation, which would both answer the Searle/Putnam challenge and provide a foundation for computational cognitive theorizing. In this paper I argue that computational cognitive models typically do not satisfy Chalmers’ notion of implementation, and so his account does not provide a conceptual foundation for computational theorizing as it is actually practiced. I argue further that the ‘in-principle’ possibility of deviant implementations of the Putnam/Searle sort does not undermine that practice – it does not make computational explanation trivial – though seeing why it doesn’t requires that we take account of the use to which a computation is put in the exercise of a cognitive capacity.

Key words: cognition, computation, explanation, implementation, use