Free will is the sensation of making a choice. The sensation is real, but the choice seems illusory. Laws of physics determine the future.

Most scientists like to operate in the context of economy. If you don't need an explanatory principle, don't invoke it.

The number of e-mails and letters that I get from choreographers, from sculptors, from composers who are being inspired by science is huge.

But, as Einstein once said, “For we convinced physicists, the distinction between past, present, and future is only an illusion, however persistent.”5

General relativity is in the old Newtonian framework where you predict what will happen, not the probability of what will happen. And putting together the probabilities of quantum mechanics with the certainty of general relativity, that's been the big challenge and that's why we have been excited about string theory, as it's one of the only approaches that can put it together.

There's a picture of my dorm room in the college yearbook as the most messy, most disgusting room on the Harvard campus, where I was an undergraduate.

That is, you can have nothingness, absolute nothingness for maybe a tiny fraction of a second, if a second can be defined in that arena, but then it falls apart into a something and an anti-something. And that something is then what we call the universe. But can we really understand that or put rigorous mathematics or testable experiments against that? Not yet. So one of the big holy grail of physics is to understand why there is something rather than nothing.