Do you remember how electrical currents and 'unseen waves' were laughed at? The knowledge about man is still in its infancy.

To dwell on the things that depress or anger us does not help in overcoming them. One must knock them down alone.

I do not share the crusading spirit of the professional atheist whose fervor is mostly due to a painful act of liberation from the fetters of religious indoctrination received in youth. I prefer an attitude of humility corresponding to the weakness of our intellectual understanding of nature and of our own being.

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.

It is the same with people as it is with riding a bike. Only when moving can one comfortably maintain one's balance.

How can cosmic religious feeling be communicated from one person to another, if it can give rise to no definite notion of a God and no theology? In my view, it is the most important function of art and science to awaken this feeling and keep it alive in those who are receptive to it.

A hundred times every day I remind myself that my inner and outer life are based on the labors of others.