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.

Many a prophecy, by the mere force of its being believed, is transmuted to fact.

Why is it, I wonder, that anyone who displays superior athletic ability is an object of admiration to his classmates, while one who displays superior mental ability is an object of hatred?

And in man is a three-pound brain which, as far as we know, is the most complex and orderly arrangement of matter in the universe.

Happiness is doing it rotten your own way.

To bring about destruction by overcrowding, mass starvation, anarchy, the destruction of our most cherished values, there is no need to do anything. We need only do nothing except what comes naturally, and breed. And how easy it is to do nothing

Scientific apparatus offers a window to knowledge, but as they grow more elaborate, scientists spend ever more time washing the windows.