Most people complain that life is too short. They say that Nature cheated us — that she gave us too little time, and that what little she gave slips through our fingers before we even notice it's gone. Ordinary people feel this. Educated people feel this. Even great doctors and philosophers have said it.  The famous line goes: "Art is long, life is short." Aristotle himself argued against Nature, accusing her of being cruel — of giving deer and ravens centuries to live, while giving humans,...