The important thing is not to stop questioning. Curiosity has its own reason for existing. One cannot help but be in awe when he contemplates the mysteries of eternity, of life, of the marvelous structure of reality. It is enough if one tries merely to comprehend a little of this mystery every day. Never lose a holy curiosity.

Let me tell you what I look like: pale face, long hair, and a tiny start of a paunch. In addition, an awkward gait, and a cigar in the mouth and a pen in pocket or hand.

I am convinced that some political and social activities and practices of the Catholic organizations are detrimental and even dangerous for the community as a whole, here and everywhere. I mention here only the fight against birth control at a time when overpopulation in various countries has become a serious threat to the health of people and a grave obstacle to any attempt to organize peace on this planet.

Men marry women with the hope they will never change. Women marry men with the hope they will change. Invariably they are both disappointed.

If I were not a Jew I would be a Quaker.

Conventional words or other signs have to be sought for laboriously only in a second stage, where the associative play already referred to is sufficiently established and can be reproduced at will.

Time and space are modes by which we think and not conditions in which we live.