Few concepts have offered greater scope for human cruelty than the idea of an immortal soul that stands independent of all material influences, ranging from genes to economic systems. Within a religious framework, a belief in free will supports the notion of sin--which seems to justify not only harsh punishment in this life but eternal punishment in the next. And yet, ironically, one of the fears attending our progress in science is that a more complete understanding of ourselves will dehumanize us. Viewing