God cannot be solemn, or he would not have blessed man with the incalculable gift of laughter.

Nuclear war is inevitable, says the pessimists; Nuclear war is impossible, says the optimists; Nuclear war is inevitable unless we make it impossible, says the realists.

Parents - and teachers too - are woefully short-sighted when they try to protect the child from his mistakes, when they make the "right answer" more important than the quest for knowledge and good judgment. For what is not learned within one's self cannot be learned from another.

Much as a teacher may wince at the thought, he is also an entertainer—for unless he can hold his audience, he cannot really instruct or edify them.

The greatest enemy of progress is not stagnation, but false progress.

Isolation always perverts; when a man lives only among his own sort, he soon begins to believe that his sort are the best sort. This attitude breeds both the arrogance of the conservative and the bitterness of the radical.

Democracy is the only system that persists in asking the powers that be whether they are the powers that ought to be.