No one knows when a robot will approach human intelligence, but I suspect it will be late in the 21st century. Will they be dangerous? Possibly. So I suggest we put a chip in their brain to shut them off if they have murderous thoughts.

In the 1950s, we had all these B-grade science-fiction movies. The point was to scare the public and get them to buy popcorn. No attempt was made to create movies that were somewhat inherent to the truth.

The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative.

Futurism today is led by science-fiction writers, by sociologists, by historians. Now, I have nothing against them. I'm sure they do great work. But they're not scientists. They're clueless.

No one knows who wrote the laws of physics or where they come from. Science is based on testable, reproducible evidence, and so far we cannot test the universe before the Big Bang.

I had two passions when I was a child. First was to learn about Einstein's theory and help to complete his dream of a unified theory of everything. That's my day job. I work in something called string theory. I'm one of the founders of the subject. We hope to complete Einstein's dream of a theory of everything.

A hydrogen bomb, for me, was puny compared to the Big Bang - the creation of the universe. That's what I really wanted to work on - the nature of the universe itself, and that's what I do for a living.