I’ve spent something like 17 years working on a theory for which there is essentially no direct experimental support.

That is, you can have nothingness, absolute nothingness for maybe a tiny fraction of a second, if a second can be defined in that arena, but then it falls apart into a something and an anti-something. And that something is then what we call the universe. But can we really understand that or put rigorous mathematics or testable experiments against that? Not yet. So one of the big holy grail of physics is to understand why there is something rather than nothing.

Cosmology is among the oldest subjects to captivate our species. And it’s no wonder. We’re storytellers, and what could be more grand than the story of creation?

A watch worn by a particle of light would not tick at all. Light realizes the dreams of Ponce de Leon and the cosmetics industry: it doesn't age.

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?'

Free will is the sensation of making a choice. The sensation is real, but the choice seems illusory. Laws of physics determine the future.

According to inflation, the more than 100 billion galaxies, sparkling throughout space like heavenly diamonds, are nothing but quantum mechanics writ large across the sky. To me, this realization is one of the greatest wonders of the modern scientific age.