If all of mathematics disappeared, physics would be set back by exactly one week.

There are thousands of years in the past, and there is an unknown amount of time in the future. There are all kinds of opportunities, and there are all kinds of dangers.

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.

The only way to deep happiness is to do something you love to the best of your ability

If you have any talent, or any occupation that delights you, do it, and do it to the hilt. Don't ask why, or what difficulties you may get into.

I don't have to be good because they think I'm going to be good.

I have argued flying saucers with lots of people. I was interested in possible. They do not appreciate that the problem is not to demonstrate whether it's possible or not but whether it's going on or not.