Man must not check his reason by tradition, but, contrariwise, must check tradition by reason.

The most important of all sciences man can and must learn is the science of living so as to do the least evil and the greatest possible good.

Happiness consists of living each day as if it were the first day of your honeymoon and the last day of your vacation.

Real wisdom is not the knowledge of everything, but the knowledge of which things in life are necessary, which are less necessary, and which are completely unnecessary to know.

Some mathematician said that pleasure lies not in discovering the truth but in searching for it.

A leader is the wave pushed ahead by the ship.

At school he had done things which had formerly seemed to him very horrid and made him feel disgusted with himself when he did them; but when later on he saw that such actions were done by people of good position and that they did not regard them as wrong, he was able not exactly to regard them as right, but to forget about them entirely or not be at all troubled at remembering them.