Joshua Greene’sMoral Tribesis a book about the origins of our moral disagreements and how to overcome them. Greene, who directs the Moral Cognition Lab at Harvard University, presents the reader with an accessible account of recent work on the psychology of moral judgment. This research, he argues, not only explains our deepest moral disputes, but also reveals a rational standard that we can use to resolve them. In a culture that is both painfully riven by moral disagreement and greatly impressed by the achievements of science, this is an enticing proposition.
Greene’s proposal is that we should do whatever maximizes happiness. Everyone’s happiness should be treated as equally valuable, and the impartiality of this principle will make it suitable for overcoming the tribalism that leads us to favor the interests of members of our own group over those of outsiders. Agreement at the level of general principle would not guarantee complete agreement on moral issues, but any remaining disputes would concern empirical claims about what would do the most to promote happiness. “Public moral debate should be a lot wonkier,” Greene argues.