Almost no one cites Sellars, while reinventing his wheels with gratifying regularity. (Dennett 1987, 349)In philosophy of mind, there is functionalism about mental states and functionalism about mental contents. The former — mental State functionalism — says that mentalstatesare individuated by their functional relations with mental inputs, Outputs, and other mental states. The latter — usually called functional or conceptual or inferential role semantics — says that mentalcontentsare constituted by their functional relations with mental inputs, Outputs, and other mental contents (and in some versions of the theory, with things in the environment). If we add to mental State functionalism the popular view that mental states have their content essentially, then mental state functionalism may be seen as a form of functional role semantics and a solution to theproblem of mental content,namely, the problem of giving a naturalistic explanation of mental content. According to this solution, the functional relations that constitute contents are physically realized — in a metaphysically unmysterious way — by the functional relations between mental inputs, outputs, and the mental states bearing those contents.
