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 believe in astrology; I'm a Sagittarius and we're skeptical.
The limits of the possible can only be defined by going beyond them into the impossible.
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.