Using Tautologies and Contradictions

Abstract

Tautologies are necessarily true, contradictions necessarily false, and so one might expect neither of them to be conversationally useful. Since at least Grice 1975, however, felicitous uses of tautologies have been noted. In this paper, I present an analysis of felicitous uses of tautologies and contradictions where each gives rise to an implication. For tautologies, this implication is a specific conversational implicature, an uncontrollability implicature; for contradictions it is part of the literal content, a contextual restriction that arises as a result of the process of semantic interpretation. I argue that other accounts of these phenomena have not been sufficiently general.