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.

War cannot be humanized. It can only be abolished.

The idea of a personal God is quite alien to me and seems even naïve.

Long live impudence. It was my guardian angel in this world.

The finest emotion of which we are capable is the mystic emotion.

Those people have seen 'something'. What it is I do not know and I can not care to know.

I believe in mystery and, frankly, I sometimes face this mystery with great fear. In other words, I think that there are many things in the universe that we cannot perceive or penetrate, and that also we experience some of the most beautiful things in life only in a very primitive form. Only in relation to these mysteries do I consider myself to be a religious man.