Present global culture is a kind of arrogant newcomer. It arrives on the planetary stage following four and a half billion years of other acts, and after looking about for a few thousand years declares itself in possession of eternal truths. But in a world that is changing as fast as ours, this is a prescription for disaster. No nation, no religion, no economic system, no body of knowledge, is likely to have all the answers for our survival. There must be many social systems that would work far better than any now in existence. In the scientific tradition, our task is to find them.

Indeed the reasoned criticism of a prevailing belief is a service to the proponents of that belief; if they are incapable of defending it, they are well advised to abandon it. This self-questioning and error-correcting aspect of the scientific method is its most striking property.

In the deepest sense the search for extraterrestrial intelligence is a search for ourselves.

Except for fools and madmen, everyone knows that nuclear war would he an unprecedented human catastrophe.

we make our world significant by the courage of our questions and the depth of our answers

The fossil record implies trial and error, an inability to anticipate the future, features inconsistent with an efficient Great Designer (although not with a Designer of a more remote and indirect temperament)

But I try not to think with my gut. If I'm serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me into trouble.