Children will ask when the world is going to end or when they're going to die; or if they'll have to lie on cold linoleum in a pool of some other child's blood and pretend to be dead so they have a chance to survive. Whatever answer anyone comes up with, it won't ever be enough and the world won't lack for so-called metaphysical questions. What I mean is, trimming basil a few days ago, I nicked my finger hard with the tip of the kitchen shears. I flinched and bled but didn't faint or die; today I can see the wound closing. I know lizards leave their tails behind when in danger, and grow them back again. In a time-lapse video, you can watch a decapitated sea slug grow another heart and a whole new body from the pulsing jelly of its severed parts. The scientist who looped a nylon thread around its neck and pulled tight in opposite directions is off-camera, but you can see the moment when its goopy head pops off like a piece of polymer slime then wobbles to the side. If only the fluid particles in our human bodies could stretch and slide like that.