Abstract

According to Tarski, a theory of truth for a language L is a theory which logically implies for each sentence S of L a sentence of the form:S is true-in-L if and only if p,where rS1 is replaced by a canonical description of a sentence of L and rp1 is replaced by that sentence if L is contained in the metalanguage or by a translation of S if it is not so contained. Tarski constructed consistent and finitely axiomatized theories of truth for various formal languages and showed how to explicitly define ‘is true in L’ within these theories. We all agree that Tarski's theories of truth have enormous philosophical significance, but there is much less agreement on precisely what that significance consists in.