In physics, you don't have to go around making trouble for yourself - nature does it for you.

The answer to the ancient question Why is there something rather than nothing would be that nothingis unstable.

In physics, your solution should convince a reasonable person. In math, you have to convince a person who's trying to make trouble. Ultimately, in physics, you're hoping to convince Nature. And I've found Nature to be pretty reasonable.

I believe that everything you've said is not even wrong.

An ordinary mistake is one that leads to a dead end, while a profound mistake is one that leads to progress. Anyone can make an ordinary mistake, but it takes a genius to make a profound mistake.

If you don't make mistakes, you're not working on hard enough problems. And that's a big mistake.

Many of my heroes, like Galileo, Maxwell, Newton and, less explicitly, Einstein thought what they were doing was finding out what God is. All of them had this inspiration that if you want to find out what God is, you have to look at his work.