Point set topology is a disease from which the human race will soon recover.

Just as houses are made of stones, so is science made of facts.

Absolute space, that is to say, the mark to which it would be necessary to refer the earth to know whether it really moves, has no objective existence.... The two propositions: "The earth turns round" and "it is more convenient to suppose the earth turns round" have the same meaning; there is nothing more in the one than in the other.

In the old days when people invented a new function they had something useful in mind.

But all of my efforts served only to make me better acquainted with the difficulty, which in itself was something.

It is the simple hypotheses of which one must be most wary; because these are the ones that have the most chances of passing unnoticed.

Thus, be it understood, to demonstrate a theorem, it is neither necessary nor even advantageous to know what it means.