Rigidity and factivity

Abstract David Chalmers argued against the claim that for all p , or even for all entertainable p , it is knowable a priori that p iff actually p . Instead of criticizing Chalmers’s argument, I suggest that it can be generalized, in a sense, and in interesting ways, concerning other principles about contingent a priori truths. In particular, I will argue that the puzzle presented by Chalmers runs parallel to others that do not turn on ‘actually’. Furthermore, stronger arguments can be presented that do not turn on apriority either, though they do entail the conclusion of Chalmers’s argument. All such puzzles involve interactions between rigidifying sentence-forming devices with factive operators.