Frege on Truth (1986)

This chapter shows that Frege's argument that sentences have truth values as their Bedeutungen (denotations) depends on his composition principle for denotation and on his view of the theoretically most important feature of sentences that functionally depends on their denotations. Frege's argument is contrasted with the Church–Gödel argument and with Russell's view of the semantical values of sentences. Frege's view that predicates are literally functional expressions, his account of the incompleteness (unsaturatedness) of predicate expressions, his attempt to clarify the notion of an extension of a concept, and his redundancy view of truth are discussed as grounds for his claim that truth values are literally logical objects. Frege's pragmatic view of theory-building is emphasized throughout. The chapter rebuts Dummett's claim that Frege's claim that truth values are denotations of sentences is an ‘almost unmitigated disaster’. In particular, Dummett's claim that Frege lost track of the distinction between sentences (which are the vehicles of assertion) and singular terms (which are not) in his logical theory is shown to be false, even of Frege's formal language. Although Frege's claims that predicates denote functions and that truth values are objects are rejected, these claims are much more pragmatically motivated and much less momentous than most commentary assumes. Frege's account of which logical objects the truth values are to be identified with is shown to be thoroughly motivated, and not merely a stipulation. Truth is the basic logical object in Frege's system.