Quine on Ethics: The Gavagai of Moral Discourse is the first comprehensive treatment of Quine’s brief yet memorable foray into ethics. It defends him against his most formidable critics, corrects misconceptions in the reception of his outlook on morality as a social institution and ethics as a philosophical enterprise, and restores emphasis on observationality as the impetus behind his momentous intervention in ethical theory. The central focus is on Quine’s infamous challenge to ethical theory: his thesis of the methodological infirmity of ethics as compared with science. The ultimate aim is to demonstrate that the challenge is not only valid but also valuable insofar as it identifies opportunities for reformation in moral justification