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.

Science alone of all the subjects contains within itself the lesson of the danger of belief in the infallibility of the greatest teachers of the preceding generation.

In those days, in Far Rockaway, there was a youth center for Jewish kids at the temple.... Somebody nominated me for president of the youth center. The elders began getting nervous, because I was an avowed atheist by that time.... I thought nature itself was so interesting that I didn't want it distorted like that. And so I gradually came to disbelieve the whole religion.

The electron is a theory we use; it is so useful in understanding the way nature works that we can almost call it real.

I'm trying to find out NOT how Nature could be, but how Nature IS.

So this piece of dirt waits four and a half billion years and evolves and changes, and now a strange creature stands here with instruments and talks to the strange creatures in the audience. What a wonderful world!

I think we can safely assume that no one understands quantum mechanics.