This dissertation argues that ethics is fundamentally mind-dependent. Ethics is invented by humans, to solve the problems that mutually sympathetic agents find in living together. Ethical discovery is the discovery of solutions to the kinds of problems that humans find themselves to face. Views of this kind are familiar, but I attempt to re-orient the debate. Many philosophers see questions about the foundations of ethics as fundamentally theoretical, arguing for one view or another on metaphysical or linguistic grounds. I argue that the question of which metaethical view we adopt is a substantive, first-order moral question. And, contrary to many, I think that first-order considerations speak in favour of a variety of anti-realism. We should reject the search for non-natural, mind-independent, objective moral truths as morally objectionable: it denigrates interpersonal concern, making the significance of moral and practical life dependent upon abstractions remote from what we care about and ought to care about. By contrast, seeing norms of morality and practical rationality as collectively created by processes of interpersonal sympathy shows why they matter, and explains the goals and methods of moral inquiry.