To like many people spontaneously and without effort is perhaps the greatest of all sources of personal happiness.

Whenever you find yourself getting angry about a difference of opinion, be on your guard; you will probably find, on examination, that your belief is going beyond what the evidence warrants.

To understand a name you must be acquainted with the particular of which it is a name.

It seems to us unwise to have insisted on teaching geometry to the younger Dionysius, tyrant of Syracuse, in order to make him a good king, but from Plato's point of view it was essential. He was sufficiently Pythagorean to think that without mathematics no true wisdom is possible.

At the age of eleven, I began Euclid, with my brother as my tutor. ... I had not imagined that there was anything so delicious in the world. After I had learned the fifth proposition, my brother told me that it was generally considered difficult, but I had found no difficulty whatsoever. This was the first time it had dawned on me that I might have some intelligence.

Mathematics rightly viewed possesses not only truth but supreme beauty.

If two hitherto rival football teams, under the influence of brotherly love, decided to co-operate in placing the football first beyond one goal and then beyond the other, no one's happiness would be increased