A Critical Study of the Functionalist Account of Mental States on the Basis of the Definition of Function and Multiple Realizability

According to the type identity theory of the mind, mental states are identical to brain states. The functionalist theory of the mind, on the other hand, defines mental states on the basis of their functional role in our neurological systems. The type identity theory has been criticized in the literature on various grounds, the most important of which concerns the idea of multiple realizability. According to the multiple realizability theory, different brain states, although they may have different physical structure, can realize the same mental states. This means that differentbeings, despite being radically different in terms of their brain structure, can have the same mental states. The main criticism of functionalists of the type identity theory concerns the idea of multiple realizability, namely, that the type identity theory cannot give a plausible account of multiple realizability. The main claim in this paper is that the functional account falls prey to the same pitfall. In order to substantiate the claim, I will first propose a new version of the multiple realizability theory, followed by the argument that the functional account cannot explain the new version of multiple realizability. It is concluded that in terms of explaining the idea of multiple realizability, the functionalist account does not enjoy any particular advantage over its rival, namely the type identity theory.