“It is not enough to be wrong, one must also be polite.”

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

The opposite of every great idea is another great idea.

Einstein, stop telling God what to do!

Prediction is very difficult, especially if it’s about the future.

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

Nothing exists until it is measured.

You must come to Copenhagen to work with us. We like people who can actually perform thought experiments!

No paradox, no progress.

There are trivial truths and the great truths. The opposite of a trivial truth is plainly false. The opposite of a great truth is also true.

Opposites are not contradictory but complementary.

The present state of atomic theory is characterized by the fact that we not only believe the existence of atoms to be proved beyond a doubt, but also we even believe that we have an intimate knowledge of the constituents of the individual atoms.

Oh what idiots we have all been, this is just as it must be.

Predition is risky, especially of the future.

Truth and clarity are complementary.

No, no, you’re not thinking; you’re just being logical.

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