In many cultures it is customary to answer that God created the universe out of nothing. But this is mere temporizing. If we wish courageously to pursue the question, we must, of course ask next where God comes from? And if we decide this to be unanswerable, why not save a step and conclude that the universe has always existed?

One of the great commandments of science is: 'Mistrust arguments from authority.'

If all the suns but ours collapsed tonight, how many lifetimes would it take us to realize that we were alone?

The universe seems neither benign nor hostile, merely indifferent.

If our long-term survival is at stake, we have a basic responsibility to our species to venture to other worlds. Sailors on a becalmed sea, we sense the stirring of a breeze.

Anything else you're interested in is not going to happen if you can't breathe the air and drink the water. Don't sit this one out. Do something. You are by accident of fate alive at an absolutely critical moment in the history of our planet.

I would love to believe that when I die I will live again, that some thinking, feeling, remembering part of me will continue.