“The only way of discovering the limits of the possible is to venture a little way past them into the impossible.”

“1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.3. Any sufficiently advanced technology is indistinguishable from magic.”

“When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

“Imagine that you're an intelligent extraterrestrial, concerned only with verifiable truths. You discover a species that has divided itself into thousands - no, by now millions - of tribal groups holding an incredible variety of beliefs about the origin of the universe and the way to behave in it. Although many of them have ideas in common, even when there's 99% overlap, the remaining one percent's enough to set them killing and torturing each other, over trivial points of doctrine, utterly meaningless to outsiders. "How to account for such irrational behavior? (...) religion was the by-product of fear - a reaction to a mysterious and often hostile universe. For much of human prehistory, it may have been a necessary evil - but why was it so much more evil than necessary - and why did it survive when it was no longer necessary?”

“Every revolutionary idea seems to evoke three stages of reaction. They may be summed up by the phrases: (1) It's completely impossible. (2) It's possible, but it's not worth doing. (3) I said it was a good idea all along.”

“Though the man-apes often fought and wrestled one another, their disputes very seldom resulted in serious injuries. Having no claws or fighting canine teeth, and being well protected by hair, they could not inflict much harm on one another. In any event, they had little surplus energy for such unproductive behavior; snarling and threatening was a much more efficient way of asserting their points of view.”

“...if one had to think about every footstep one took, ordinary walking would be impossible.”