Abstract: This is a book in metaethics that defends a brand of moral realism known as non-naturalism. The book has five Parts. Part I outlines the sort of moral realism that the author wishes to defend, and then offers critiques of expressivism and constructivism. Part II is devoted to issues in metaphysics. It argues that moral realists have adequate replies to worries based on supervenience and the alleged causal inefficacy of moral facts. Part III is devoted to issues of moral motivation. It argues that motivational internalism is false, and that a Humean theory of action is also mistaken. Part IV is devoted to an extended discussion of moral reasons. It argues that externalism about reasons is true, that moral rationalism is true, and that moral realism has an adequate account of moral disagreement. Part V is devoted to moral epistemology. It argues for the self-evidence of pro tanto moral principles, and for a version of reliabilism about ethical knowledge.

Keywords: externalism about reasons, metaethics, moral disagreement, moral epistemology, moral facts, moral motivation, moral rationalism, moral realism, moral reasons, motivational internalism, non-naturalism, reliabilism, self-evidence/self-evident, supervenience