False Truths

One of the most interesting and fruitful applications of logics, classical or other, has been in supplying formal frameworks for the semantics of natural language. In this paper, I discuss the following puzzle: there seem to be arguments that are logically valid - more precisely, that are instances of the rule of universal instantiation, and yet, the utterance of the premise is intuitively true while the conclusion is false. I will discuss two strategies, developed in response to different sorts of problems, that seem immediately applicable to this puzzle. While the so-called contextualist strategy blocks the puzzle at the level of syntax, the index-shifting strategy actually embraces the apparently paradoxical claim that there are logically valid arguments with premises whose utterances are true and a conclusion whose utterance is false, but insists that different points of evaluation come into play in determining the truth values of the utterances involved in the alleged counter-instances to rules of logic