It is not easy to see how the more extreme forms of nationalism can long survive when men have seen the Earth in its true perspective as a single small globe against the stars.

What was more, they had taken the first step toward genuine friendship. They had exchanged vulnerabilities.

I've been saying for a long time that I'm hoping to find intelligent life in Washington.

The one fact about the future of which we can be certain is that it will be utterly fantastic.

It is a good principle in science not to believe any 'fact'---however well attested---until it fits into some accepted frame of reference. Occasionally, of course, an observation can shatter the frame and force the construction of a new one, but that is extremely rare. Galileos and Einsteins seldom appear more than once per century, which is just as well for the equanimity of mankind.

Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living.

Open the pod bay doors, Hal.