Those whose conscience demands that they defy authority in some ways that involve great consequences must be willing to accept some penalty.

Technology made large populations possible; large populations now make technology indispensable.

Science has always promised two things not necessarily related; an increase first in our powers, second in our happiness or wisdom, and we have come to realize that it is the first and less important of the two promises which it has kept most abundantly.

The impulse to mar and to destroy is as ancient and almost as nearly universal as the impulse to create. The one is an easier way than the other of demonstrating power.

It is not ignorance but knowledge which is the mother of wonder.

Whenever man forgets that man is an animal, the result is always to make him less humane.

Man is the only one in whom the instinct of life falters long enough to enable it to ask the question "Why?