Type-Identity Theory and Conceptual Diversity

In the debate on type-identity theory, the topic of conceptual diversity has been touched on several occasions. Smart (1959) discussed a number of possible objections to type-identity theory, which in fact merely attack a strong version of type-identity theory, rather than the version he, and, according to him. Place tried to defend. These alleged counter-arguments roughly run as follows (Smart 1959, 146 ff.) There is no conceptual route from the mental to the physical, and, therefore, the relevant identity-claims are mistaken. lfa = b, then it is conceptually necessary 

even here, the nomological thesis is prior to its equivalent (though not identical) counterparts. Something similar holds for the weaker claim that the set of actual types is the set of nomoiogicaliy possible types. 

The way Smart s anonymous opponent conceives of the connection between identity statements and conceptual necessity is, to some extent, mimicked by a way of talking according to which kinds or types are more kin to concepts as conceived of here than to non-representational entities. The idea that there is a conceptual connection between the mental and the physical is tied to a fa on de parler that can be found in various parts of the debate on reductionism and type-identity theory, according to which we can analyze kinds, events or states in functional terms (cf. Block 1995 Kim 2005, 167 Jackson 2005). Type-identity theorists hold that mental types or kinds or properties are identical to physical types or kinds or properties. This suggests that mental kinds and physical kinds are non-representational objects - an interpretation that seems rather plausible given that type-identity theory is a metaphysical theory. Necessarily, there are no conceptual connections between kinds (or non-representational worldly entities), just because kinds are not the right sort of entities to instantiate conceptual relations in any nonderivative way. Kinds are the subject of ontological claims about mental properties. 

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