As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.

The scientist finds his reward in what Henri Poincare calls the joy of comprehension, and not in the possibility of application to which any discovery may lead.

Nature conceals her secrets because she is sublime, not because she is a trickster.

I was very pleased with your kind letter. Until now I never dreamed of being something like a hero. But since you've given me the nomination I feel that I am one.

The value of achievement lies in the achieving.

Insofar as we may at all claim that slavery has been abolished today, we owe its abolition to the practical consequences of science

It is the supreme art of the teacher to awaken joy in creative expression and knowledge.