Mathematics are well and good but Nature keeps dragging us around by the nose.

To take those fools in clerical garb seriously is to show them too much honor.

The contemplation of this world beckoned as a liberation (...)The road to this paradise was not as comfortable and alluring as the road to the religious paradise; but it has shown itself reliable, and I have never regretted having chosen it.

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

The environment is everything that isn't me.

Nobody knows how the stand of our knowledge about the atom would be without him. Personally, [Niels] Bohr is one of the amiable colleagues I have met. He utters his opinions like one perpetually groping and never like one who believes himself to be in possession of the truth.

Pure logical thinking cannot yield us any knowledge of the empirical world. All knowledge of reality starts from experience and ends in it.