Abstract

In this paper, I present an explanatory gap argument against the view that the semantic facts are fully grounded in the physical facts. Unlike traditional explanatory gap arguments, which stem from the failure of analytic reductive explanation, the explanatory gap I point to stems from the failure of metaphysical explanation. I argue for the following theses. (i) Physicalist grounding claims are metaphysically necessary, if true. (ii) To be explanatorily adequate, these grounding claims must be deducible from facts about essence. (iii) Semantico-physical grounding claims are possibly false, not (only) because they are conceivably false, but because they cannot be deduced from facts about essence. (iv) Semantic properties are essentially weakly normative: it lies in their natures to have correctness conditions and subjectively rationalize—rather than merely cause—behaviour. This gives rise to an explanatory gap that indicates that the semantic facts are not fully grounded in the physical facts.