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 like to think that Einstein would look at string theory’s journey and smile, enjoying the theory’s remarkable geometrical features while feeling kinship with fellow travelers on the long and winding road toward unification.

My emotional investment is in finding truth. If string theory is wrong, I'd like to have known that yesterday. But if we can show it today or tomorrow, fantastic.

Time allows change to take place and the very evolution of the universe is what requires some conception of time. Mathematically can we write down a universe that doesn't have time? Sure. Do we think that would be realised in the larger reality that is out there? None of us take that possibility seriously.

There are many of us thinking of one version of parallel universe theory or another. If it's all a lot of nonsense, then it's a lot of wasted effort going into this far-out idea. But if this idea is correct, it is a fantastic upheaval in our understanding.

...quantum mechanics—the physics of our world—requires that you hold such pedestrian complaints in abeyance.

...things are the way they are in our universe because if they weren't, we wouldn't be here to notice.