 Some of the earliest versions of analytic functionalism (Lewis 1966, Armstrong 1968 — but see Lewis 1980, for a modification) were presented as functional specification theories, as topic-neutral “translations” of mental state terms that could pave the way for a psycho-physical identity theory by defusing the Distinct Property Argument (see section 3.3). However, if there are differences in the physical states that satisfy the functional definitions in different (actual or hypothetical) creatures, such theories—like most versions of the identity theory—would violate a key motivation for functionalism, namely, that creatures with states that play the same role in the production of other mental states and behavior possess, literally, the same mental states. 