In Britain, like most of the developed world, stem-cell research is regarded as a great opportunity. America will be left behind if it doesn't change policy.

We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet.

One does not have to appeal to God to set the initial conditions for the creation of the universe, but if one does He would have to act through the laws of physics.

A model is a good model if first it interprets a wide range of observations in terms of a simple and elegant model, and second if the model makes definite predictions that can be tested, and possibly falsified, by observation.

So Einstein was wrong when he said, "God does not play dice." Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen.

There is a real danger that computers will develop intelligence and take over.

We are entering an increasingly dangerous period of our history. But I'm an optimist.