Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute. That's relativity.

Coincidence is God's way of remaining anonymous.

Try to become not a man of success, but try rather to become a man of value.

I do not know with what weapons World War III will be fought, but World War IV will be fought with sticks and stones. Letter to Harry S. Truman.

Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution.

Science without religion is lame, religion without science is blind.

You cannot simultaneously prevent and prepare for war.

Wisdom is not a product of schooling but of the lifelong attempt to acquire it.

It has become appallingly obvious that our technology has exceeded our humanity.

Nothing will benefit human health and increase chances for survival of life on Earth as much as the evolution to a vegetarian diet.

It is my conviction that killing under the cloak of war is nothing but an act of murder.

So many people today — and even professional scientists — seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is — in my opinion — the mark of distinction between a mere artisan or specialist and a real seeker after truth. Letter to Robert A. Thorton, Physics Professor at University of Puerto Rico (7 December 1944).