Arthur C. Clarke

It has yet to be proven that intelligence has any survival value.

New ideas pass through three periods: 1) It can't be done. 2) It probably can be done, but it's not worth doing. 3) I knew it was a good idea all along!

This is the first age that's ever paid much attention to the future, which is a little ironic since we may not have one.

How inappropriate to call this planet Earth when it is quite clearly Ocean.

Sometimes I think we're alone in the universe, and sometimes I think we're not. In either case the idea is quite staggering.

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.

The only way to discover the limits of the possible is to go beyond them into the impossible.

The limits of the possible can only be defined by going beyond them into the impossible.

Perhaps, as some wit remarked, the best proof that there is Intelligent Life in Outer Space is the fact it hasn't come here. Well, it can't hide forever - one day we will overhear it.

I don't pretend we have all the answers. But the questions are certainly worth thinking about.

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?

Human judges can show mercy. But against the laws of nature, there is no appeal.