Metaphysics and Epistemology Group (Tuesday - Week 5, HT24)

This talk is about a clash between two big picture views of the indicative conditional. On one picture, the entailment picture, the indicative expresses a kind of (perhaps sui generis) entailment relation; standard strict and variably strict theories fall in this camp. On the second picture, the restrictor picture, conditional antecedents restrict the interpretation of material in their consequents, particularly modals and conditionals; a leading example of this kind of theory is Kratzer's restrictor semantics.

While these two pictures are not obviously in competition, I argue that they cannot both be maintained in full generality. I argue that the restrictor picture is best understood as a commitment to a principle I call Persistence, the principle that "If A, then if C then A" is valid; I show that, by combining Persistence with a very minimal implementation of the entailment picture, we can prove a battery of new triviality results. I argue that the best approach here is to implement the entailment view in terms of informational validity, a notion introduced by Veltman 1996 and Yalcin 2008. This approach preserves the central structural features of the entailment picture. It also gives us a theoretically satisfying restriction of the Persistence principle, one that suffices to block triviality.