From terror attacks to the war on terror, real estate bubbles to the price of oil, sexual predators to poisoned food from China, our list of fears is ever-growing. And yet, we are the safest and healthiest humans in history. Irrational fear seems to be taking over, often with tragic results. For example, in the months after 9/11, when people decided to drive instead of flyabelieving they were avoiding riskaroad deaths rose by more than 1,500. In this...