Wisdom is not a product of schooling but of the lifelong attempt to acquire it.

A human being is part of a whole called by us the universe.

It is a very grave mistake to think that the enjoyment of seeing and searching can be promoted by means of coercion and a sense of duty.

I refuse to make money out of my science. My laurel is not for sale like so many bales of cotton.

The creative principle [of science] resides in mathematics.

The bitter and the sweet come from the outside, the hard from within, from one's own efforts.

Is there not a certain satisfaction in the fact that natural limits are set to the life of the individual, so that at the conclusion it may appear as a work of art?