Harry Frankfurt Journal of Philosophy, 66, 829–39 famously attacked what he called the principle of alternate possibilities. PAP states that being able to do otherwise is necessary for moral responsibility. He gave counterexamples to PAP known since then as “Frankfurt cases.” This paper sidesteps the enormous literature on Frankfurt cases while preserving some of our salient pretheoretical intuitions about the relation between alternate possibilities and moral responsibility. In particular, I introduce, explain, and defend a principle that has so far been (...) overlooked, namely, “the principle of doxastic moral asymmetry” : a rational agent, S, is morally responsible for an action that S performed, E, only if, when S did E, S justifiably believed either that E was closer to S’s most praiseworthy alternate possibility than it was to S’s most blameworthy alternate possibility, or that E was closer to S’s most blameworthy alternate possibility than it was to S’s most praiseworthy alternate possibility. (shrink)