I am neither especially clever nor especially gifted. I am only very, very curious.

Happiness, as a pursuit, is suitable only for pigs.

Make everything as simple as possible, but not simpler. A man should look for what is, and not for what he thinks should be. We cannot solve our problems with the same thinking we used when we created them. A question that sometimes drives me hazy: am I or are the others crazy? Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction. All religions, arts and sciences are branches of the same tree. It's not that I'm so smart, it's just that I stay with problems longer.

I wouldn't want to live if I did not have my work. In any case, it's good that I'm already old and personally don't have to count on a prolonged future.

A religious person is devout in the sense that he has no doubt about the significance of those superpersonal objects and goals which neither require nor are capable of rational foundation

Feeling and longing are the motive forces behind all human endeavor and human creations.

I am a determinist. As such, I do not believe in free will. The Jews believe in free will. They believe that man shapes his own life. I reject that doctrine philosophically. In that respect I am not a Jew.