ABSTRACT
Philosophy.—The language of thought (LOT) is a special language (→ LANGUAGE) that has been postulated by a number of writers (Wilfrid Sellars, Gilbert Harman, Jerry Fodor) to explain how humans and many animals represent and think about the world (→ANIMAL COGNITION, COGNITIVISM, INTENTIONALITY, REPRESENTATION). It is claimed to be coded into their brains in the way certain formal languages are coded into the circuitry of a computer. There are different theories of how these symbols possess meaning, but most of them appeal to causal relations among the symbols (which might mirror a process of inference) and/or to causal relations the individual symbols bear to phenomena in the world (for example, a symbol S might causally covary with snow) (→CAUSALITY AND MENTAL CAUSATION, SYMBOL). The LOT need not be a natural language (that people use for speaking); indeed, given that the relevant sorts of intelligent behavior are displayed by many creatures that lack a nat-ural language, such as infants and chimpanzees (→INFANT COGNITION), its postulation need not be confined to natural language users. What makes it a language is that it possesses semantically valuable, causally efficacious logicosyntactic structure; that is, it consists, for example, of names, predicates, variables, quantifiers (all, some), and logical connectives (not, and, only if) that are combined to form complex sentences that can be true or false (→LOGIC, PROPOSITIONAL FORMAT, SEMANTICS, SYNTAX). In this way, the LOT is superior in its expressive power to systems of pure images, for instance (→MENTAL IMAGERY), which seem incapable of expressing logically complex thoughts (e.g., that someone doesn’t love everyone).
