So the universe is not quite as you thought it was. You'd better rearrange your beliefs, then. Because you certainly can't rearrange the universe.

All roads lead to Trantor, says the old proverb, and that is where all stars end.

How often people speak of art and science as though they were two entirely different things, with no interconnection. That is all wrong. The true artist is quite rational as well as imaginative and knows what he is doing; if he does not, his art suffers. The true scientist is quite imaginative as well as rational, and sometimes leaps to solutions where reason can follow only slowly; if he does not, his science suffers.

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.

It is no defense of superstition and pseudoscience to say that it brings solace and comfort to people. . . . If solace and comfort are how we judge the worth of something, then consider that tobacco brings solace and comfort to smokers; alcohol brings it to drinkers; drugs of all kinds bring it to addicts; the fall of cards and the run of horses bring it to gamblers; cruelty and violence bring it to sociopaths. Judge by solace and comfort only and there is no behavior we ought to interfere with.

The greatest weapons in the conquest of knowledge are an understanding mind and the inexorable curiosity that drives it on.

Surely no child, and few adults, have ever watched a bird in flight without envy.