Abstract

The essay argues that, on their usual metalinguistic reconstructions, the open question argument and Frege’s puzzle are variants of the same argument. Each are arguments to a conclusion about a difference in meaning; each deploy compositionality as a premise; and each deploy a premise linking epistemic features of sentences with their meaning (which, given certain meaning-platonist assumptions, can be interpreted as a universal instantiation of Leibniz’s law). Given these parallels, each is sound just in case the other is. They are, in fact, unsound. The essay first argues that reformulations of these arguments directly in terms of Leibniz’s law are unsound and then that subarguments of the metalinguistic versions are unsound for structurally similar reasons. Finally, given how the theory/observation distinction is deployed in linguistic practice, the meaning-platonist assumptions are shown to be optional.