A soul might very well exist, but we, as physicists, try to measure and quantify everything. So far, no one has been able to create an experiment to do this for the soul. Efforts have been made to weigh the body after death, but each time we find no evidence of a soul. So a soul may very well exist, but it is not a testable theory.

Scientists are embarrassed by science fiction; they want to distance themselves as much as possible. ... I think there's nothing to be ashamed of [and that] we should take science fiction seriously.

In general, the larger the breeding population, the slower the rate of evolution.

We need an enduring, robust theory of education. Now, it seems education careens from one fad to another and often back again. I think that with better education and students willing to put in the 10,000-hours to become expert, we could develop better science professionals, even theoretical physicists.

I hope we find evidence of dark matter in the lab and in outer space. This would go a long way to proving the correctness of string theory, which is what I do for a living. That is my day job. So string theory is a potentially experimentally verifiable theory.

‎By 2100, our destiny is to become like the gods we once worshipped and feared. But our tools will not be magic wands and potions but the science of computers, nanotechnology, artificial intelligence, biotechnology, and most of all, the quantum theory.

The reactors in Japan are stable in the same way that a ticking time bomb is also stable. It wouldn't take much to light the fuse - a 6.6 earthquake, like what happened today in Japan, a pipe break, an over-pressurized containment vessel - anything could set it off, in which case we would have another Chernobyl, three times the magnitude of a Chernobyl accident.