Conspiracy Theories: Causes and Cures*

Many millions of people hold conspiracy theories; they believe that powerful people have worked together in order to withhold the truth about some important practice or some terrible event. A recent example is the belief, widespread in some parts of the world, that the attacks of 9/11 were carried out not by Al Qaeda, but by Israel or the United States. Those who subscribe to conspiracy theories may create serious risks, including risks of violence, and the existence of such theories raises significant challenges for policy and law. The first challenge is to understand the mechanisms by which conspiracy theories prosper; the second challenge is to understand how such theories might be undermined. Such theories…