When I give this talk to a physics audience, I remove the quotes from my 'Theorem'.

Before the discovery of quantum mechanics, the framework of physics was this: If you tell me how things are now, I can then use the laws of physics to calculate, and hence predict, how things will be later.

I wouldn't say that The Fabric of the Cosmos is a book on cosmology. Cosmology certainly plays a big part, but the major theme is our ever-evolving understanding of space and time, and what it all means for our sense of reality.

I believe that through its rational evaluation of truth and indifference to personal belief, science transcends religious and political divisions and so does bind us into a greater, more resilient whole.

If the theory turns out to be right, that will be tremendously thick and tasty icing on the cake.

The bottom line is that time travel is allowed by the laws of physics.

In my own research when I'm working with equations, I never feel like I really understand what I'm doing if I'm solely relying on the mathematics for my understanding. I need to have a visual picture in my mind. I'm constantly translating from the math to some intuitive mind's-eye picture.