Joshua Greene, of Harvard University and author of Moral Tribes: Emotion, Reason, and the Gap Between Us and Them, talks with EconTalk host Russ Roberts about morality and the challenges we face when our morality conflicts with that of others. Topics discussed include the difference between what Greene calls automatic thinking and manual thinking, the moral dilemma known as "the trolley problem," and the difficulties of identifying and solving problems in a society that has a plurality of values. Greene defends utilitarianism as a way of adjudicating moral differences.