Guns are the crutches of the impotent.

The space elevator will be built about 50 years after everyone stops laughing.

We over estimate technology in the short term and under estimate technology in the long term.

Floyd could imagine a dozen things that could go wrong; it was little consolation that it was always the thirteenth that actually happened.

There is a special sadness in achievement, in the knowledge that a long-desired goal has been attained at last, and that life must now be shaped toward new ends.

We have to abandon the idea that schooling is something restricted to youth. How can it be, in a world where half the things a man knows at 20 are no longer true at 40 - and half the things he knows at 40 hadn't been discovered when he was 20?

When one has to ask, "Am I really in love?" the answer is always "No".