If we are to be destroyed we will do it ourselves by warfare with thermonuclear weaponry.

The uniformity of the earth's life, more astonishing than its diversity, is accountable by the high probability that we derived, originally, from some single cell, fertilized in a bolt of lightning as the earth cooled.

A lot of people fear death because they think that so overwhelming an experience has to be painful, but I've seen quite a few deaths, and, with one exception, I've never known anyone to undergo anything like agony. That's amazing when you think about it. I mean, how complicated the mechanism is that's being taken apart.

We leave traces of ourselves wherever we go, on whatever we touch.

Our behavior toward each other is the strangest, most unpredictable, and most unaccountable of all the phenomena with which we are obliged to live. In all of nature, there is nothing so threatening to humanity as humanity itself.