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?"

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

The only way of finding the limits of the possible is by going beyond them into the impossible.

The moon is the first milestone on the road to the stars.

"If an elderly but distinguished scientist says that something is possible he is almost certainly right, but if he says that it is impossible he is very probably wrong."