Robert A. Heinlein - Gulf

If the average man thinks at all, he does silly things like generalizing from a single datum. He uses one-valued logics. If he is exceptionally bright, he may use two-valued, 'either-or' logic to arrive at his wrong answers. If he is hungry, hurt, or personally interested in the answer, he can't use any sort of logic and will discard an observed fact as blithely as he will stake his life on a piece of wishful thinking. He uses the technical miracles created by superior men without wonder nor surprise, as a kitten accepts a bowl of milk. Far from aspiring to higher reasoning, he is not even aware that higher reasoning exists. He classes his own mental proccess as being of the same sort as the genius of an Einstein. Man is not a rational animal; he is a rationalizing animal.

A dozen Heinlein quotations for sci fi day