Functionalism is a theory about the nature of mental states. According to functionalism, mental states are identified by what they do rather than by what they are made of. This can be understood by thinking about artifacts like mousetraps and keys. In particular, the original motivation for functionalism comes from the helpful comparison of minds with computers. But that is only an analogy. The main arguments for functionalism depend on showing that it is superior to its primary competitors: identity theory and behaviorism. Contrasted with behaviorism, functionalism retains the traditional idea that mental states are internal states of thinking creatures. Contrasted with identity theory, functionalism introduces the idea that mental states
