The future is an unknown, but a somewhat predictable unknown. To look to the future we must first look back upon the past. That is where the seeds of the future were planted. I never think of the future. It comes soon enough.

If men as individuals surrender to the call of their elementary instincts, avoiding pain and seeking satisfaction only for their own selves, the result for them all taken together must be a state of insecurity, of fear, and of promiscuous misery.

Imagination is the highest form of research.

Let every man judge according to his own standards, by what he has himself read, not by what others tell him.

You cannot solve current problems with current thinking. Current problems are the result of current thinking.

I prefer an attitude of humility corresponding to the weakness of our intellectual understanding of nature and of our own being.

Knowledge is limited.