Prior's Puzzle Generalized

Justin D'Ambrosio (Australian National University)

Justin D'Ambrosio (ANU) will present "Prior's Puzzle Generalized" at 11 in Old Arts 224 on 11 October.

Abstract: Prior's puzzle is the puzzle of why, given the assumption that that-clauses denote propositions, substitution of "the proposition that P" for "that P" within the complements of many propositional attitude verbs is invalid. I show that there are two variants on Prior's puzzle---a quantificational variant and a pronominal variant---that have the same source and warrant the same solution as the original puzzle. I then show that neither the original puzzle nor its variants are specific to that-clauses or propositional attitude verbs. Rather, they arise in the complements of all kinds of attitude verbs, in adjectival positions, in adverbial positions, and in a variety of other positions as well. These variants, together with the generalization to other grammatical categories, show that a wide range of proposed solutions to Prior's puzzle fail, or are radically incomplete. But the quantificational variant of the puzzle also has a more dire consequence: it threatens to undermine Lewis's method of defining theoretical terms via Ramsification. I go on to discuss the relative merits of two approaches to the generalized puzzle, and conclude that one has significant advantages.