Not how the world is, but that it is, is the mystery.

The popular scientific books by our scientists aren't the outcome of hard work, but are written when they are resting on their laurels.

I think one of the things you and I have to learn is that we have to live without the consolation of belonging to a Church.... Of one thing I am certain. The religion of the future will have to be extremely ascetic, and by that I don't mean just going without food and drink.

The sole remaining task for philosophy is the analysis of language.

There can never be surprises in logic.

What Copernicus really achieved was not the discovery of a true theory but of a fertile new point of view.

Mathematics is a logical method. . . . Mathematical propositions express no thoughts. In life it is never a mathematical proposition which we need, but we use mathematical propositions only in order to infer from propositions which do not belong to mathematics to others which equally do not belong to mathematics.