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.

The pessimist sees only the tunnel; the optimist sees the light at the end of the tunnel; the realist sees the tunnel and the light - and the next tunnel.

The art of listening needs its highest development in listening to oneself; our most important task is to develop an ear that can really hear what we're saying.

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.

Elitism is the slur directed at merit by mediocrity.

When you run into someone who is disagreeable to others, you may be sure he is uncomfortable with himself; the amount of pain we inflict upon others is directly proportional to the amount we feel within us.

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.