The hypothesis especially associated with Fodor, that mental processing occurs in a language different from one’s ordinary native language, but underlying and explaining our competence with it. The idea is a development of the Chomskyan notion of an innate universal grammar. It is a way of drawing the analogy between the workings of the brain or mind and those of a standard computer, since computer programs are linguistically complex sets of instructions whose execution explains the surface behaviour of the computer. As an explanation of ordinary language learning and competence the hypothesis has not found universal favour. It apparently only explains ordinary representational powers by invoking innate things of the same sort, and it invites the image of the learning infant being a ‘little linguist’ who translates the language surrounding it back into an innate language whose own powers are a mysterious biological given. See also theory-theory.