The values by which we are to survive are not rules for just and unjust conduct, but are those deeper illuminations in whose light justice and injustice, good and evil, means and ends are seen in fearful sharpness of outline.

We are a scientific civilization. That means a civilization in which knowledge and its integrity are crucial. Science is only a Latin word for knowledge ... Knowledge is our destiny.

We have to understand that the world can only be grasped by action, not by contemplation. The hand is more important than the eye ... The hand is the cutting edge of the mind.

You will die but the carbon will not; its career does not end with you. It will return to the soil, and there a plant may take it up again in time, sending it once more on a cycle of plant and animal life.

To me the most interesting thing about man is that he is an animal who practices art and science and in every known society practices both together.

That series of inventions by which man from age to age has remade his environment is a different kind of evolution -- not biological, but cultural evolution . . . "The Ascent of Man.

Revolutions are not made by fate but by men.