All seem a little awkward and not to have an inner beauty we usually expect from truth. But sometimes the truth is discovered first and the beauty or 'necessity' of the truth seen only later.

The opposite of a fact is a falsehood, but the opposite of one profound truth may very well be another profound truth.

An expert is a man who has made all the mistakes which can be made in a very narrow field

Every description of natural processes must be based on ideas which have been introduced and defined by the classical theory.

While the finish given to our picture of the world by the theory of relativity has already been absorbed into the general scientific consciousness, this has scarcely occurred to the same extent with those aspects of the general problem of knowledge which have been elucidated by the quantum theory.

Humanity will... be confronted with dangers of unprecedented character unless, in due time, measures can be taken to forestall a disastrous competition in such formidable armaments and to establish an international control of the manufacture and use of the powerful materials.

Technology has advanced more in the last thirty years than in the previous two thousand. The exponential increase in advancement will only continue.

Our task is not to penetrate the essence of things, the meaning of which we do not know anyway, but rather to develop concepts which allow us to talk in a productive way about phenomena in nature.

Truth and clarity are complementary.

The very fact that knowledge is itself the basis for civilization points directly to openness as the way to overcome the present crisis.