Is it rational to be moral? Can moral disputes be settled rationally? Which criteria determine what we have a good reason to do? In this innovative book, Logi Gunnarsson takes issue with the assumptions made by many philosophers faced with the problem of reconciling moral norms with a scientific world view. His discussion includes substantial critical engagement with thinkers from two very different traditions, and is notable for its clear account of Habermas' discourse ethics. It will appeal to anyone interested in practical reason and the rational credentials of morality.