The New and Old Ignorance Puzzles: How badly do we need closure?

摘要

Skeptical puzzles and arguments often employ knowledge-closure principles (e.g. If S knows that P, and knows that P entails Q, then S knows that Q). Epistemologists widely believe that an adequate reply to the skeptic should explain why her reasoning is appealing albeit misleading; but it's unclear what would explain the appeal of the skeptic's closure principle, if not for its truth. In this paper, I aim to challenge the widespread commitment to knowledge-closure. But I proceed by first examining a new puzzle about failing to know-what I call the New Ignorance Puzzle (Sects. 1-3). This puzzle resembles to the Old Ignorance Puzzle (i.e. the closure-based skeptical puzzle), although it does not involve a closure principle. It instead centers on the standard view of ignorance, a highly intuitive principle stating that ignorance is merely a failure to know. In Sects. 2 and 3, I argue that the best way to solve the New Ignorance Puzzle is to reject the standard view of ignorance and to explain away its appeal via conversational implicature. I then use this solution to the New Ignorance Puzzle as a way of explaining why knowledge-closure principles would seem true, and why abominable conjunctions would seem abominable, even if such principles were false (Sect. 4). The upshot is a new way of explaining why the skeptic's reasoning is appealing albeit misleading.