Nationalism is an infantile disease. It is the measles of mankind.

Creating a new theory is not like destroying an old barn and erecting a skyscraper in its place. It is rather like climbing a mountain and gaining new and wider views.

Considered logically this concept is not identical with the totality of sense impressions referred to; but it is an arbitrary creation of the human (or animal) mind.

No amount of experimentation can ever prove me right; a single experiment can prove me wrong.

With me every peep becomes a trumpet solo.

The supreme task of the physicist is to arrive at those universal elementary laws from which the cosmos can be built up by pure deduction. There is no logical path to these laws; only intuition, resting on sympathetic understanding of experience, can reach them.

The environment is everything that isn't me.