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

At this time I had complete confidence in Russian policy and believed that the Western Allies deliberately allowed Germany and Russia to fight each other to death.

You have to learn the rules of the game. And then you have to play better than anyone else.

Look deep into nature, and then you will understand everything better.

One may say the eternal mystery of the world is its comprehensibility.

It should be possible to explain the laws of physics to a barmaid.

I went first to France and then to England where I studied and at the same time I tried to make a serious study of the basic Marxist philosophy.

Only one who devotes himself to a cause with his whole strength and soul can be a true master. For this reason mastery demands all of a person.

Weakness of attitude becomes weakness of character.

Any intelligent fool can make things bigger and more complex… It takes a touch of genius – and a lot of courage to move in the opposite direction.

The only source of knowledge is experience.

Try not to become a man of success, but rather try to become a man of value.

It has become appallingly obvious that our technology has exceeded our humanity.

Knowledge of what is does not open the door directly to what should be.

The pursuit of truth and beauty is a sphere of activity in which we are permitted to remain children all our lives.

Before I joined the project most of the English people with whom I had made personal contacts were left wing and affected to some degree or other by the same kind of philosophy.

No problem can be solved from the same level of consciousness that created it.

Force always attracts men of low morality.

A person who never made a mistake never tried anything new.

A man should look for what is, and not for what he thinks should be.

Some time before this I had also joined a student organization which contained members of the S.P.D. as well as members of the Communist Party.

The devil has put a penalty on all things we enjoy in life. Either we suffer in health or we suffer in soul or we get fat.

Love is a better teacher than duty.

Only two things are infinite, the universe and human stupidity, and I’m not sure about the former.

Our task must be to free ourselves by widening our circle of compassion to embrace all living creatures and the whole of nature and its beauty.

The only thing that interferes with my learning is my education.

It is my conviction that killing under the cloak of war is nothing but an act of murder.

As far as I’m concerned, I prefer silent vice to ostentatious virtue.

Concern for man and his fate must always form the chief interest of all technical endeavors. Never forget this in the midst of your diagrams and equations.

Finally Germany’s attack on Russia seemed to confirm that Russia was not shirking and was prepared to carry out a foreign policy with the risk of war with Germany.

There comes a time when the mind takes a higher plane of knowledge but can never prove how it got there.

There are two ways to live: you can live as if nothing is a miracle; you can live as if everything is a miracle.

He who joyfully marches in rank and file has already earned my contempt. He has been given a large brain by mistake, since for him the spinal cord would suffice.

I do not believe in immortality of the individual, and I consider ethics to be an exclusively human concern with no superhuman authority behind it.

The Communist Party said that I must finish my studies because after the revolution in Germany people would be required with technical knowledge to take part in the building of the Communist Germany.

Nothing is more destructive of respect for the government and the law of the land than passing laws which cannot be enforced.

Intellectuals solve problems, geniuses prevent them.

All that is valuable in human society depends upon the opportunity for development accorded the individual.

There could be no fairer destiny for any physical theory than that it should point the way to a more comprehensive theory in which it lives on as a limiting case.

It’s not that I’m so smart, it’s just that I stay with problems longer.

Occurrences in this domain are beyond the reach of exact prediction because of the variety of factors in operation, not because of any lack of order in nature.

God always takes the simplest way.

Politics is for the present, but an equation is for eternity.

I carried on the negotiations with the leaders of the Nazi group at the University, proposing that we should organize a strike of the students.

It was the experience of mystery – even if mixed with fear – that engendered religion.

Pure mathematics is, in its way, the poetry of logical ideas.

Most people say that is it is the intellect which makes a great scientist. They are wrong: it is character.

We should take care not to make the intellect our god; it has, of course, powerful muscles, but no personality.

The last time when I handed over information was in February or March 1949.