The Language of Thought

A defence of the idea that thinking takes place in an internal, language-like system of mental representations, often called Mentalese. An introduction defends psychology as a special science whose laws need not reduce to physics. The first chapter starts from the cognitive psychology of his day, which explained perception, learning and decision as computations, and argues that computation needs a medium: a system of symbols with a syntax over which mental processes run. The second chapter gives his best-known argument. Learning a word or concept means forming and testing hypotheses about what it applies to, but forming a hypothesis already requires a language in which to frame it, so the language of thought cannot itself be learned; it must be innate, and at least as expressive as any natural language we later acquire. The last two chapters look at linguistic and psychological evidence about the structure of this internal code. Critics have found the nativism about concepts implausible, and Fodor himself later revised parts of it.

It is the founding statement of the computational theory of mind and a key text for cognitive science and debates about artificial intelligence.