For a fresh perspective on ethics, Schur turns to the existentialist philosophers of mid-19th-century France, including Jean-Paul Sartre and Albert Camus. Sartre argued that human existence is meaningless and that there is no god or overarching moral force to make sense of the universe. Instead, we alone are responsible for who we are and what we do. This gives us freedom to choose, but Sartre also stresses that by choosing, we are presenting a model of behavior to others, so we must choose thoughtfully. Like a soldier who must decide between comforting his mother following his brother’s death in battle and going to avenge that death by fighting himself, we must choose for ourselves. Religion, philosophy, and other would-be guides are ultimately useless.

Camus’s existentialism, meanwhile, centered on the premise that human life is fundamentally absurd. We can resolve or escape that absurdity in one of three ways: through death, through social structures such as religion or family, or through accepting the absurdity without allowing it to defeat us. He compares this approach to that of Sisyphus, a character from Greek mythology who was cursed to repeatedly push a boulder up a hill for eternity; the boulder, Camus argues, gave Sisyphus structure and purpose without imposing some grand meaning.