Soul. The word rebounded to me, and I wondered, as I often had, what it was exactly. People talked about it all the time, but did anybody actually know? Sometimes I'd pictured it like a pilot light burning inside a person--a drop of fire from the invisible inferno people called God. Or a squashy substance, like a piece of clay or dental mold, which collected the sum of a person's experiences--a million indentations of happiness, desperation, fear, all the small piercings of beauty we've ever known.