SEMANTIC EXTERNALISM AND A PRIORI SELF-KNOWLEDGE

Abstract

The argument known as the ‘McKinsey Recipe’ tries to establish the incompatibility of semantic externalism (about natural kind concepts in particular) and a priori self-knowledge about thoughts and concepts by deriving from the conjunction of these theses an absurd conclusion, such as that we could know a priori that water exists. One reply to this argument is to distinguish two different readings of ‘natural kind concept’: (i) a concept which in fact denotes a natural kind, and (ii) a concept which aims to denote a natural kind. Paul Boghossian has argued, using a Dry Earth scenario, that this response fails, claiming that the externalist cannot make sense of a concept aiming, but failing, to denote a natural kind. In this paper I argue that Boghossian’s argument is flawed. Borrowing machinery from two-dimensional semantics, using the notion of ‘considering a possible world as actual’, I claim that we can give a determinate answer to Boghossian’s question: which concept would ‘water’ express on Dry Earth?¹