Niels Bohr

When asked ... [about] an underlying quantum world, Bohr would answer, 'There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about Nature.'

An independant reality in the ordinary physical sense can neither be ascribed to the phenomenon nor to the agencies of observation.

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

Those who are not shocked when they first come across quantum theory cannot possibly have understood it.

When searching for harmony in life one must never forget that in the drama of existence we are ourselves both actors and spectators.

And anyone who thinks they can talk about quantum theory without feeling dizzy hasn't yet understood the first thing about it.

Everything we call real is made of things that cannot be regarded as real.

Einstein, stop telling God what to do!

The old saying of the two kinds of truth. To the one kind belongs statements so simple and clear that the opposite assertion obviously could not be defended. The other kind, the so-called 'deep truths', are statements in which the opposite also contains deep truth.

If an idea does not appear bizarre, there is no hope for it.

If anybody says he can think about quantum physics without getting giddy, that only shows he has not understood the first thing about them.

Of course I don't believe in it [pointing to horseshoe on his office wall]. But I understand that it brings you luck whether you believe in it or not.

A physicist is just an atom's way of looking at itself.

Anyone who can contemplate quantum mechanics without getting dizzy hasn't understood it.

Every sentence I utter must be understood not as an affirmation, but as a question.

It is the hallmark of any deep truth that its negation is also a deep truth.

The best weapon of a dictatorship is secrecy, but the best weapon of a democracy should be the weapon of openness.

When it comes to atoms, language can be used only as in poetry.

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.

Your theory is crazy, but it's not crazy enough to be true.

How wonderful that we have met with a paradox. Now we have some hope of making progress.