Self-Evidence and A Priori Moral Knowledge

According to rationalists about moral knowledge, some moral truths are knowable a priori. Rationalists often defend their position by claiming that some moral propositions are self-evidently true. Copp 2007 has recently challenged this rationalist strategy. Copp argues that even if some moral propositions are self-evident, this is not enough to secure rationalism about moral knowledge, since it turns out that such self-evident propositions are only knowable a posteriori. This paper considers the merits of Copp’s challenge. After clarifying the rationalists’ appeal to self-evidence, I show why this rationalist strategy survives Copp’s challenges to it.