Fatalism and the Logic of Unconditionals

Abstract

In this paper, I consider a variant of the ancient Idle Argument involving so-called “unconditionals” with interrogative wh-antecedents. This new Idle Argument provides an ideal setting for probing the logic of these close relatives of if-conditionals, which has been comparatively underexplored. In the course of refuting the argument, I argue that contrary to received wisdom, many wh-conditionals are not properly speaking ‘unconditional’ in that they do not entail their main clauses, yet modus ponens remains valid for this class of expressions. I make these lessons formally precise in a semantic system that integrates recent decision-theoretic approaches to deliberative modals with ideas from inquisitive semantics. My larger aim is to challenge standard truth preservation views of logic and deductive argumentation.