Ethical naturalists interpret moral knowledge as analogous to scientific knowledge and not dependent on intuition. For their account to succeed, moral truths must explain observable phenomena, and these explanations (i) must be better than any explanations framed in non-moral terms, (ii) must not rely on ad hoc posits about the causal powers of moral properties, and (iii) must not presuppose the existence of an independent means of awareness of moral truths. No moral explanations satisfy these criteria.