Separated by millennia, Aristotle and Sigmund Freud gave us disparate but compelling pictures of the human condition. But if, with Jonathan Lear , we scrutinize these thinkers' attempts to explain human behavior in terms of a higher principle--whether happiness or death--the pictures fall apart. Aristotle attempted to ground ethical life in human striving for happiness, yet he didn't understand what happiness is any better than we do. Happiness became...