Type-identity statements and the explanatory gap: An argument for compatibility

This paper challenges a popular thesis which we call the explanatory primitiveness thesis (for short, EPT), namely, the thesis that identities leave no logical space wherein explanatory questions may be formulated and explanatory gaps may reside. We argue that while EPT is, in all likelihood, flawless when the relevant domain consists of identity statements flanked by proper names of individuals it is a mistake to hold that the thesis generalizes to cover all identity statements. In particular, we argue that EPT fails decisively with respect to an important class of identity statements, viz., those in which natural kinds are identified across different theoretical levels (i.e., the so-called inter-level type-identities). If correct, our result shows EPT to be much more limited in scope than is usually supposed. Moreover, and perhaps more significantly, it shows that there is no inherent absurdity in the idea that certain type-identity statements, in particular psychophysical type-identity statements, suffer from an explanatory gap.