The scientist does not study nature because it is useful; he studies it because he delights in it, and he delights in it because it is beautiful.

If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living.

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

If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living

Invention consists in avoiding the constructing of useless contraptions and in constructing the useful combinations which are in infinite minority. To invent is to discern, to choose.

Mathematicians do not study objects, but relations between objects.