After centuries, we still don't understand pain. The Greeks imagined it almost as a kind of spirit, looking to gain entrance into the body through any wound. In the bible, there are more than 70 mentions of the word pain or suffering. The pain of childbirth, the grief after loved ones die, the pain of lepers and others afflicted with disease; boils, thorns, nails, and crosses— All are meant to illustrate that what comes after pain is the more important experience. Scripture boils down to just one message: wait for it. As for theories of natural selection, organisms that display a nimble ability to survive often do so at the expense of others. The human hand evolved to grasp a rock or fashion a metal spear. The heads of toppled strongmen or dictators were swiftly severed by guillotine; naturally, they died before they could describe how that might have felt. Phantom pain rouses an amputee in the middle of the night, so he'll clutch a leg fashioned of air and blankets. Shooting and stabbing pains send electric nerve signals from the brain to the face and mouth. Neurosurgeons probe this pain that doesn't seem to further the body's instincts for self-preservation: microvascular decompression, stereotactic radiation. But it comes and goes at will, like a capricious god or spirit reminding you of a proverb about how the hurt in the littlest finger becomes agony for the whole body.