Fitzgerald: "The test of a first-rate intelligence is the ability to hold two opposing ideas in mind at the same time and still retain the ability to function."

Hitchens: “Some people say it’s a sign of intelligence to be able to keep two contradictory ideas in your head at the same time, and it can be a sign of intelligence. It can also be a sign of stupidity, or of unwillingness to make up the mind.”

Take your pick.