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 cliches of our forebears. We subject all facts to a prefabricated set of interpretations. We enjoy the comfort of opinion without the discomfort of thought.

Commencement address, Yale University, New Haven, Connecticut (11 June 1962)

Yale University Commencement (June 11, 1962)—Miller Center[millercenter.org]