Vagueness and the Logic of Ordinary Language

Abstract

This chapter discusses about the vagueness and the logic of ordinary language. Logic applies to the precise language of mathematicians, not the vague language of ordinary speakers. Classical logic only applies to vague predicates after they have been precisified. This preparation is standard operating procedure in the case of ambiguity. The amount of vagueness in a natural language exactly equals the amount of vagueness of any other natural language. This follows from the intertranslatability of languages. The constancy of vagueness also follows from the psychological premise that there is a single language of thought, “mentalese,” underlying all natural languages. The amount of ambiguity does vary across languages and within stages of a language. Consequently, translation can remove an ambiguity. This chapter explores application of logic to ordinary world and ordinary languages. Concepts related to vagueness in the platonic heavens and vagueness as a prelogical phenomenon are explained. It also provides details about truth–value gaps, logical pluralism, deviant logic, and many-valued logic.