Insofar as mathematics is true, it does not describe the real world. Insofar as it describes the real world, it is not true.

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

Formerly, people thought that if matter disappeared from the universe, space and time would remain. Relativity declares that space and time would disappear with matter.

I cannot conceive of a personal God who would directly influence the actions of individuals, or would directly sit in judgment on creatures of his own creation.

I have no special talent. I am only passionately curious.

Conventional words or other signs have to be sought for laboriously only in a second stage, where the associative play already referred to is sufficiently established and can be reproduced at will.

When the solution is simple, God is answering.