Everyone believes in the law of errors, the experimenters because they think it is a mathematical theorem, and the mathematicians because they think it is an experimental fact.

The “seriousness” of a mathematical theorem lies, not in its practical consequences, which are usually negligible, but in the significance of the mathematical ideas which it connects.

What we do may be small, but it has a certain character of permanence and to have produced anything of the slightest permanent interest, whether it be a copy of verses or a geometrical theorem, is to have done something utterly beyond the powers of the vast majority of men.

Young men should prove theorems, old men should write books.

The seriousness of a theorem, of course, does not lie in its consequences, which are merely the evidence for its seriousness.