You can prove anything you want by coldly logical reason---if you pick the proper postulates.

I'm not a speed reader. I'm a speed understander.

In all the known history of Mankind, advances have been made primarily in physical technology; in the capacity of handling the inanimate world about Man. Control of self and society has been left to to chance or to the vague gropings of intuitive ethical systems based on inspiration and emotion. As a result no culture of greater stability than about fifty-five percent has ever existed, and these only as the result of great human misery.

Until now in world's history, whenever we've had a dark age, its been temporary and local. And other parts of the world have been doing fine. And eventually, they help you get out of the dark age. We are now facing a possible dark age which is going to be world-wide and permanent! That's not fun. That's a different thing. But once we have established many worlds, we can do whatever we want as long as we do it one world at a time.

Old people think young people haven't learned about love. Young people think old people have forgotten about love.

Of course there are worlds. Millions of them! Every star you see has worlds, and most of those you don't see.

Knowledge is indivisible. When people grow wise in one direction, they are sure to make it easier for themselves to grow wise in other directions as well. On the other hand, when they split up knowledge, concentrate on their own field, and scorn and ignore other fields, they grow less wise - even in their own field.