If we knew exactly the laws of nature and the situation of the universe at the initial moment, we could predict exactly the situation of the same universe at a succeeding moment.

But for harmony beautiful to contemplate, science would not be worth following.

The aim of science is not things themselves, as the dogmatists in their simplicity imagine, but the relation between things.

A scientist worthy of his name, about all a mathematician, experiences in his work the same impression as an artist; his pleasure is as great and of the same nature.

It is the harmony of the diverse parts, their symmetry, their happy balance; in a word it is all that introduces order, all that gives unity, that permits us to see clearly and to comprehend at once both the ensemble and the details.

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

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