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.

Writing for the stage is different from writing for a book. You want to write in a way that an actor has material to work with, writing in the first person not the third person, and pulling out the dramatic elements in a bigger way for a stage presentation.

When we benefit from CT scanners, M.R.I. devices, pacemakers and arterial stents, we can immediately appreciate how science affects the quality of our lives.

String theory envisions a multiverse in which our universe is one slice of bread in a big cosmic loaf. The other slices would be displaced from ours in some extra dimension of space.

I would say in one sentence my goal is to at least be part of the journey to find the unified theory that Einstein himself was really the first to look for.

Over the centuries, monumental upheavals in science have emerged time and again from following the leads set out by mathematics.

Science is the process that takes us from confusion to understanding.