If what we regard as real depends on our theory, how can we make reality the basis of our philosophy? But we cannot distinguish what is real about the universe without a theory. It makes no sense to ask if it corresponds to reality, because we do not know what reality is independent of a theory.

If I have questions about the universe on my mind when I go to bed, I can't turn off. I dream equations all night.

Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill.

Then we shall... be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason - for then we would know the mind of God.

What was God doing before the divine creation? Was he preparing hell for people who asked such questions?

The idea of 10 dimensions might sound exciting, but they would cause real problems if you forget where you parked your car.

So remember to look up at the stars and not down at your feet. Try to make sense of what you see and hold on to that childlike wonder about what makes the universe exist.