The difference between faith and superstition is that the first uses reason to go as far as it can, and then makes the jump; the second shuns reason entirely — which is why superstition is not the ally, but the enemy, of true religion.

Knowledge fills a large brain; it merely inflates a small one.

We believe what we want to believe, what we like to believe, what suits our prejudices and fuels our passions.

At it's highest level, the purpose of teaching is not to teach—it is to inspire the desire for learning. Once a student's mind is set on fire, it will find a way to provide its own fuel.

Just about the only interruption we don't object to is applause.

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.

We must become masters of our own actions and attitudes. To let another person determine whether we will be rude or gracious, elated or depressed is to give control of ourselves. The only true possession is self possession.