The book uses evolutionary principles to explain tribalism, a way of thinking and acting that divides the world into Us versus Them and achieves cooperation within a group at the expense of erecting insuperable obstacles to cooperation among groups. Tribalism represents political controversies as supreme emergencies in which ordinary moral constraints do not apply and as zero-sum, winner take all contests. Tribalism not only undermines democracy by ruling out compromise, bargaining, and respect for the Other; it also reverses one of (...) the most important milestones of progress in how we understand morality: the insight that morality is not a list of commands to be unthinkingly followed, but rather that morality centrally involves the giving and taking of reasons among equals. Tribalism rejects this insight by branding the Other as a being who is incapable of reasoning. (shrink)