[T]he number of grains of sand on all the Earth’s beaches is only about 10²⁰.

It’s possible, of course, that general relativity is not the correct theory of gravity on cosmological scales ….

Inflation has a lot going for it, but it makes the need for a theory of initial conditions even more pressing.

The state of the early universe was not chosen randomly among all possible states. Everyone in the world who has thought about the problem agrees with that. What they don’t agree on is why the early universe was so special―what is the mechanism that put it in that state?

The arrow of time … is not a feature of the underlying laws of physics, at least as far as we know.

Concepts like “time” are not handed to us unambiguously by the outside world but are invented by human beings trying to make sense of the universe.

“In the beginning,” he said, “exactly fifteen point two billion years ago, there was a Big Bang and the Universe–”
I had stopped writing. “Fifteen billion years ago?” I said incredulously.
“Absolutely,” he said. “I’m inspired.”