I have repeatedly said that in my opinion the idea of a personal God is a childlike one.

I believe that Gandhi’s views were the most enlightened of all the political men of our time.

I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones.

[Freud's] sense of reality is less clouded by wishful thinking than is the case with other people and [he combines] the qualities of critical judgment, earnestness and responsibility.

Everything that can be counted does not necessarily count; everything that counts cannot necessarily be counted.

You ask me if I keep a notebook to record my great ideas. I've only ever had one.

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