The moon does not simply disappear when we are not looking at it.

The goal of pacifism is possible only though a supranational organization. To stand unconditionally for this cause is the criterion of true pacifism.

Organized people are just too lazy to go looking for what they want.

I cannot accept any concept of God based on the fear of life or the fear of death, or blind faith. I cannot prove to you that there is no personal God, but if I were to speak of him I would be a liar.

It is every man's obligation to put back into the world at least the equivalent of what he takes out of it.

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.

There is, fortunately, a minority composed of those who recognize early in their lives that the most beautiful and satisfying experiences open to humankind are not derived from the outside, but are bound up with the development of the individual's own feeling, thinking and acting. The genuine artists, investigators and thinkers have always been persons of this kind. However inconspicuously the life of these individuals runs its course, none the less the fruits of their endeavors are the most valuable contributions which one generation can make to its successors.