Moral reasoning performance determines epistemic peerdom.

We offer a friendly criticism of May's fantastic book on moral reasoning: It is overly charitable to the argument that moral disagreement undermines moral knowledge. To highlight the role that reasoning quality plays in moral judgments, we review literature that he did not mention showing that individual differences in intelligence and cognitive reflection explain much of moral disagreement. The burden is on skeptics of moral knowledge to show that moral disagreement arises from non-rational origins.