Abstract
Ontological functionalism's defining tenet is that mental properties can be defined wholly in terms of the general pattern of interaction of ontologically prior realizations. Ideological functionalism's defining tenet is that mental properties can only be defined nonreductively, in terms of the general pattern of their interaction with one another. My Self-consciousness Argument establishes: ontological functionalism is mistaken because its proposed definitions wrongly admit realizations into the contents of self-consciousness; ideological functionalism is the only viable alternative for functionalists. Michael Tooley's critique misses the target: he offers no criticism of - except for an incidental, and incorrect, attack on certain self-intimation principles - and, since he himself proposes a certain form of nonreductive definition, he tacitly accepts. Finally, as with all other nonreductive definitions, Tooley's proposal can be shown to undermine functionalism's ultimate goal: its celebrated materialist solution to the Mind-Body Problem. The explanation of these points will require a discussion of: Frege-Russell disagreements regarding intensional contexts; the relationship between self-consciousness and the traditional doctrine of acquaintance; the role of self-intimation principles in functionalist psychology; and the Kripke-Lewis controversy over the nature of theoretical terms.