Man owes his strength in the struggle for existence to the fact that he is a social animal.

Knowledge is realizing that the street is one way; wisdom is looking in both directions anyway.

Only a life lived for others is a life worthwhile.

Play is the highest from of research.

If you feed your mind as often as you feed your stomach, then you'll never have to worry about feeding your stomach or a roof over your head or clothes on your back.

If someone feels that he has never made a mistake in his life, it only means that he has never tried anything new in his life.

It is very difficult to explain this feeling to anyone who is entirely without it, especially as there is no anthropomorphic conception of God corresponding to it. The individual feels the nothingness of human desires and aims and the sublimity and marvelous order which reveal themselves both in Nature and in the world of though. He looks upon individual existence as a sort of prison and wants to experience the universe as a single significant whole.