Does Frege Have a Metalinguistic Truth-Predicate in Begriffsschrift?

Abstract

AbstractIn the explanations of logical laws and inference rules of the mature version of Begriffsschrift in Grundgesetze, Frege uses the predicate “… is the True.” Scholars like Greimann maintain that this predicate is a metalinguistic truth-predicate for Frege. This paper examines an argument for this claim that is based on the “nominal reading” of Frege’s conception of sentences—the claim that for Frege a sentence “$ p $” is equivalent to a nonsentential phrase like “the truth-value of the thought that $ p $.” In particular, this paper attempts to establish two points concerning this argument based on the nominal reading. First, the argument implies a claim about the nature of assertion which Frege repeatedly denies in his mature works. Secondly, the nominal reading on which the argument depends is false. A sentence “$ p $” is not equivalent to a nonsentential phrase like “the truth-value of the thought that $ p $” for Frege. Our discussion will lead to an important lesson about Frege’s conception of sentences and of assertion.