The present is no more exempt from the sneer of the future than the past has been.

Mathematics, even in its present and most abstract state, is not detached from life. It is just the ideal handling of the problems of life.

The next-most difficult thing in the world is to get perspective. The most difficult is to keep it.

Absolute certainty is a privilege of uneducated minds and fanatics. - It is, for scientific folk, an unattainable ideal.

The pursuit of excellence is the proper vocation of man.

It is commonly, but erroneously, believed that it is easy to ask questions. A fool, it is said, can ask questions that a wise man cannot answer. The fact is that a wise man can answer many questions that a fool cannot ask.

The validity of mathematical propositions is independent of the actual world-the world of existing subject-matters-is logically prior to it, and would remain unaffected were it to vanish from being. Mathematical propositions, if true, are eternal verities.