We absolutely must leave room for doubt or there is no progress and no learning. There is no learning without having to pose a question. And a question requires doubt. People search for certainty. But there is no certainty.

[B]eyond poverty, beyond the point that the material needs are reasonably satisfied, only from within is peace.

Another thing I must point out is that you cannot prove a vague theory wrong.

We absolutely must leave room for doubt or there is no progress and there is no learning. There is no learning without having to pose a question. And a question requires doubt. People search for certainty. But there is no certainty. People are terrified — how can you live and not know? It is not odd at all. You only think you know, as a matter of fact. And most of your actions are based on incomplete knowledge and you really don’t know what it is all about, or what the purpose of the world is, or know a great deal of other things. It is possible to live and not know.

I learned from her that every woman is worried about her looks, no matter how beautiful she is.

Work hard to find something that fascinates you.

The game I play is a very interesting one. It's imagination in a straightjacket, which is this: that it has to agree with the known laws of physics. ... It requires imagination to think of what's possible, and then it requires an analysis back, checking to see whether it fits, whether its allowed, according to what's known, okay?