In this essay we provide (1) an argument for why ethics should be naturalized, (2) an analysis of why it is not yet naturalized, (3) a defense of ethical naturalism against two fallacies—Hume’s and Moore’s—that ethical naturalism allegedly commits, and (4) a proposal that normative ethics is best conceived as part of human ecology committed to pluralistic relativism. We explain why naturalizing ethics both entails relativism and also constrains it, and why nihilism about value is not an especially worrisome for (...) ethical naturalists. The substantive view we put forth constitutes the essence of Duke Naturalism. (shrink)