For the great enemy of the truth is very often not the lie–deliberate,contrived, and dishonest–but the myth–persistent, persuasive, and unrealistic.Too often we hold fast to the clichés of our forebears. We subject all facts toa prefabricated set of interpretations. We enjoy the comfort of opinionwithout the discomfort of thought.Former U.S. President John F. Kennedy, Commencement Address at YaleUniversity, June 11, 1962.