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

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

If people would stop objectifying abstractions (which they probably never will), or if they would stop objectifying the abstractions they make consciously (which they might learn to do), at least half the pseudo-questions befuddling the world today - as they have befuddled it since time immemorial - would vanish. And that would be a very, very great gain.

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

The pursuit of excellence is the proper vocation of man.

Mathematics is, in many ways, the most precious response that the human spirit has made to the call of the infinite.