For over two thousand years it has been the custom among earnest moralists to decry happiness as something degraded and unworthy

My sad conviction is that people can only agree about what they're not really interested in.

Unhappy business men, I am convinced, would increase their happiness more by walking six miles every day than by any conceivable change of philosophy.

Your writing is never as good as you hoped; but never as bad as you feared.

There have been poverty, pestilence, and famine, which were due to man's inadequate mastery of nature. There have been wars, oppressions and tortures which have been due to men's hostility to their fellow men.

What Galileo and Newton were to the seventeenth century, Darwin was to the nineteenth.

If I were a medical man, I should prescribe a holiday to any patient who considered his work important.