The New Field of Complexity

If the basic rules of chemistry are any guide, life should not exist. Scientists showed in the 1950s that shooting an electric spark through a soup of chemicals -- thus simulating lightning strikes on the primordial planet earth -- could produce simple organic compounds. But complex, self-reproducing chemicals like dna? They shouldn't have arisen in a trillion years. At an even deeper level, the second law of thermodynamics dictates that the universe should inexorably move toward disorganization. Cups of tea always cool off; they never spontaneously get hotter. Iron rusts, but rust never turns into iron.

Yet over the eons, a...