When beauty is universal, it loses its power to move the heart, and only its absence can produce any emotional effect.

The numbers of distinct human societies or nations, when our race is twice its present age, may be far greater than the total number of all the men who have ever lived up to the present time.

If man can live in Manhattan, he can live anywhere.

Any technology distinguishable from magic is insufficiently advanced.

We stand now at the turning point between two eras. Behind us is a past to which we can never return...

Anything that is theoretically possible will be achieved in practice, no matter what the technical difficulties are, if it is desired greatly enough.

There's no real objection to escapism, in the right places... We all want to escape occasionally. But science fiction is often very far from escapism, in fact you might say that science fiction is escape into reality... It's a fiction which does concern itself with real issues: the origin of man; our future. In fact I can't think of any form of literature which is more concerned with real issues, reality.