No opinion has ever been too errant to become a creed.

What is wanted is not the will to believe, but the will to find out, which is the exact opposite.

One of the symptoms of approaching nervous breakdown is the belief that one's work is terribly important, and that to take a holiday would bring all kinds of disaster. If I were a medical man, I should prescribe a holiday to any patient who considered his or her work important.

To realize the unimportance of time is the gate to wisdom.

Ideas and principles that do harm are as a rule, though not always, cloaks for evil passions.

We must be skeptical even of our skepticism.

When you come to look into this argument from design, it is a most astonishing thing that people can believe that this world, with all the things that are in it, with all its defects, should be the best that omnipotence and omniscience has been able to produce in millions of years.