Reinhold Niebuhr once wrote that the doctrine of original sin is “the only empirically verifiable doctrine of the Christian faith.” The evidence of ingrained sinfulness, he thought, is apparent everywhere in acts of violence, in the mistreatment of the vulnerable, and in the greed built into economic systems. Even human beings’ greatest accomplishments are inevitably tainted by sins of pride and self-interest, he argued. The problem is not just that humans commit sinful acts but that they are by nature sinful.

Yet if the doctrine of original sin seems obvious to some, it is a puzzling formulation to many modern ears. (In an inspired riff on the doctrine, stand-up comedian Eddie Izzard imagines a man confessing, “I did an original sin. . . . I poked a badger with a spoon”—to which a priest replies, “I’ve never heard of that one before!”)

The doctrine attempts to answer the question of how sin originates—where it comes from. The answer handed down by the Western Christian tradition is largely shaped by Augustine, as appropriated and revised by magisterial Protestantism. As Charles Hefling notes (“Why we mess things up”), the Augustinian account is tied to a literal reading of the story of Adam and Eve in Genesis and assumes the biological transmission of sin from generation to generation—both highly problematic elements.