How Life (and Death) Spring From Disorder

Take a golf ball and a cannonball and drop them off the Tower of Pisa. The laws of physics allow you to predict their trajectories pretty much as accurately as you could wish for. Now do the same experiment again, but replace the cannonball with a pigeon. Biological systems don't defy physical laws, of course--but neither do they seem to be predicted by them. In contrast, they are goal-directed: survive and reproduce. We can say that they have a purpose--or what philosophers have traditionally called a teleology--that guides their behavior. By the same token, physics now lets us predict, starting from the state of the universe a billionth of a second after the Big Bang, what it looks like today.