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

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.

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 pursuit of excellence is the proper vocation of man.

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

[The] humanization of mathematical teaching, the bringing of the matter and the spirit of mathematics to bear not merely upon certain fragmentary faculties of the mind, but upon the whole mind, that this is the greatest desideratum is. I assume, beyond dispute.