“Although the theory of relativity makes the greatest of demands on the ability for abstract thought, still it fulfills the traditional requirements of science insofar as it permits a division of the world into subject and object (observer and observed) and, hence, a clear formulation of the law of causality.”

Every word or concept, clear as it may seem to be, has only a limited range of applicability.

Sometimes a poor performance is better for enjoyment, because you can look at those things that were wrong and analyze them.

The end of the First World War had thrown Germany’s youth into great turmoil. The reins of power had fallen from the hands of a deeply disillusioned older generation, and the younger ones drew together in larger and smaller groups to blaze new paths or, at least, to discover a new star to steer by.

If the lecture is good, then everything is too smooth. That’s the same in music: if the performance is too good, you really don’t enjoy it, because it just goes by, and you can never penetrate into the heart of it.

If we made atomic bombs, we would bring about a terrible change in the world. Who knows what would happen from this?

If this were the whole truth, we should, when entering into a new field, introduce only such quantities as can directly be observed, and formulate natural laws only by means of these quantities.

It is generally believed that our science is empirical and that we draw our concepts and our mathematical constructs from the empirical data.

Reports in Washington show that our reasoning was just like that of your physicists.

In America, it was decided to attempt the production of atomic bombs with an effort that would constitute a large part of the collective American war effort.

The solution of the difficulty is that the two mental pictures which experiment lead us to form – the one of the particles, the other of the waves – are both incomplete and have only the validity of analogies which are accurate only in limiting cases.

The problems of language here are really serious. We wish to speak in some way about the structure of the atoms. But we cannot speak about atoms in ordinary language.

I think that if a United States of Europe were to be formed, it would be in our interests to fight for it, as all our old traditions would remain in such a united Europe, whereas if we were to start now as part of the Russian Empire, everything that had ever been in Germany would disappear.

Bohr’s influence on the physics and the physicists of our century was stronger than that of anyone else, even than that of Albert Einstein.

The single life is bearable to me only through my work in science, but for the long term, it would be very bad if I had to make do without a very young person next to me.

Whoever dedicates his life to searching out particular connections of nature will spontaneously be confronted with the question how they harmoniously fit into the whole.

With all this information available, at least to privileged persons, I cannot understand why it is generally held in the United States that we completely missed the basic principle of the bomb until after Hiroshima.

What if a girl grew up like a boy, with marriage an abstract, someday thought, a thing to think about when she became an adult, a thing she could do, or not do, depending? What would that look and feel like?

I think everybody deserves freedom. Freedom is such an abstract word, but it’s all we need.

In my case, I was stuck there for quite a while. New York is large enough to be a very abstract city, so nobody cares.

Beauty and happiness and life are all the same and they are pervasive, unattached and abstract and they are our only concern.

A definition of art is that it makes concrete our most subtle emotions. I think the highest form of art is music. It’s the most abstract of all art expression.

Abstract art: a construction site for high fashion, for advertising, for furniture.

The abstract music is just more interesting because it doesn’t really have anything to say, but if it is good, it creates thoughts and feelings, and I enjoy that. For me, once the music creates those thoughts and feelings, I begin to write a song about it.

I never abstract from nature; I never consciously think of nature when I paint.