Recently a school district in rural Pennsylvania officially recognized a supposed alternative to Darwinism. In a one-minute statement read by an administrator, ninth-grade biology students were told that evolution was not a fact and were encouraged to explore a different explanation of life called intelligent design. What is intelligent design? Its proponents maintain that living creatures are just too intricate to have arisen by evolution. Throughout the natural world, they say, there is evidence of deliberate design. Is it not reasonable, then, to infer the existence of an intelligent designer? To evade the charge that intelligent design is a religious...