Frege’s Equivalence Thesis and Reference Failure

Abstract

Frege claims that sentences of the form ‘A’ are equivalent to sentences of the form ‘it is true that A’ (The Equivalence Thesis). Frege also says that there are fictional names that fail to refer, and that sentences featuring fictional names fail to refer as a result. The thoughts such sentences express, Frege says, are also fictional, and neither true nor false. Michael Dummett argues that these claims are inconsistent. But his argument requires clarification, since there are two ways The Equivalence Thesis has been formulated, according as the thesis equates the senses or the referents of the relevant sentences. I have two aims in this paper. The first is to demonstrate that a sameness of sense thesis is inconsistent with Frege’s other theses. The second is to argue that a sameness of reference thesis is consistent with them. Thus, all else being equal, Frege ought to endorse a sameness of reference, rather than a sameness of sense thesis.