This attitude of mind - this attitude of uncertainty - is vital to the scientist, and it is this attitude of mind which the student must first acquire. It becomes a habit of thought. Once acquired, we cannot retreat from it anymore.

We can deduce, often, from one part of physics like the law of gravitation, a principle which turns out to be much more valid than the derivation.

An ordinary fool isn't a faker; an honest fool is all right. But a dishonest fool is terrible!

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.

If you know that you are not sure, you have a chance to improve the situation. I want to demand this freedom for future generations.

The "paradox" is only a conflict between reality and your feeling of what reality "ought to be."

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