Niels Bohr

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

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.

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

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

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

Never express yourself more clearly than you are able to think.

Every sentence I utter must be understood not as an affirmation but as a question.[A caution he gives his students, to be wary of dogmatism.]

[About describing atomic models in the language of classical physics:]We must be clear that when it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images and establishing mental connections.