Science is a set of rules to keep us from telling lies to each other. All scientists really have is a reputation for telling the truth.

Flattery is useful when dealing with youngsters.

Every religion seems like a fantasy to outsiders, but as holy truth to those of the faith.

I can't bear to hear a human being spoken of with contempt just because of his group identification...It's these respectable people here who create those hooligans out there.

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.

The day you stop learning is the day you begin decaying.

All the hundreds of millions of people who, in their time, believed the Earth was flat never succeeded in unrounding it by an inch.