More Trouble for Functionalism

Abstract

In this paper I highlight certain logical and metaphysical issues which arise in the characterisation of functionalism—in particular its ready coherence with a physicalist ontology, its structuralism and the impredicativity of functionalist specifications. I then utilise these points in an attempt to demonstrate fatal flaws in the functionalist programme. I argue that the brand of functionalism inspired by David Lewis fails to accommodate multiple realisability though such accommodation was vaunted as a key improvement over the identity theory. More standard accounts of functionalism allow, by contrast, for far too much multiple realisability. Specifically, functionalist structures will be massively reduplicated in the human brain; so functionalism yields the absurd consequence that each human harbours large numbers of minds and exemplifies virtually all mental states.