One of the basic things about a string is that it can vibrate in many different shapes or forms, which gives music its beauty.

But the beauty of Einstein's equations, for example, is just as real to anyone who's experienced it as the beauty of music. We've learned in the 20th century that the equations that work have inner harmony.

One very important aspect of string theory is definitely testable. That was the prediction of supersymmetry, which emerged from string theory in the early '70s.

It's indeed surprising that replacing the elementary particle with a string leads to such a big change in things. I'm tempted to say that it has to do with the fuzziness it introduces.

As of now, string theorists have no explanation of why there are three large dimensions as well as time, and the other dimensions are microscopic. Proposals about that have been all over the map.

I have a tendency, more than most other physicists, to try to figure out everything all at once, before I publish. And even to try to figure out everything in my head, without pencil and paper.

You enter a completely new world where things aren't at all what you're used to.