Validity

Abstract

The suggestion that emerges from the discussion of the uniqueness thesis is that two significantly different notions of logical form may be contemplated: the truth-conditional notion, which suits the logical role, and the syntactic notion, which suits the semantic role. Since the suitability of the syntactic notion for the semantic role is not in question, the best way to substantiate our suggestion is to develop the idea that the truth-conditional notion fulfils the logical role. This chapter outlines an account of validity that accords with the truth-conditional view. In order to show that the account is independently justified, we will test it on three challenging problems: the first is the paradox of the sorites, the second concerns the fallacy of equivocation, the third arises in connection with arguments affected by context sensitivity.