I believe the process of going from confusion to understanding is a precious, even emotional, experience that can be the foundation of self-confidence.

Einstein comes along and says, space and time can warp and curve, that's what gravity is. Now string theory comes along and says, yes, gravity, quantum mechanics, electromagnetism - all together in one package, but only if the universe has more dimensions than the ones that we see.

I was holding [my four-year-old daughter] and I said, 'Sophia, I love you more than anything in the universe.' And she turned to me and said, 'Daddy, universe or multiverse?'

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

Gravity is matter’s sugar daddy.

One of the wonders of science is that it is completely universal. It crosses national boundaries with total ease.

The central idea of string theory is quite straightforward. If you examine any piece of matter ever more finely, at first you'll find molecules, atoms, sub-atomic particles. Probe the smaller particles, you'll find something else, a tiny vibrating filament of energy, a little tiny vibrating string.