Abstract

Richard Foley has presented a puzzle purporting to show that all attempts in trying to find a sufficient condition of rationality are doomed. The puzzle rests on two plausible assumptions. The first is a level-connecting principle: if one rationally believes that one's belief that p is irrational, then one's belief that p is irrational. The second is a claim about a structural feature shared by all promising sufficient conditions of rationality: for any such condition, it is possible that one's belief satisfies it and yet one rationally believes that it doesn’t. With the two assumptions, Foley argues that a sufficient condition of rationality is impossible. I explain how exactly the puzzle goes and I try to offer a solution. If my solution works, all theorists of rationality who accept certain level-connecting principles need to add an extra condition to their favourite rationality-making condition