We should seek the greatest value of our action.

Observations indicate that the universe is expanding at an ever-increasing rate. It will expand forever, getting emptier and darker. Although the universe doesn’t have an end, it had a beginning in the Big Bang. One might ask what is before that but the answer is that there is nowhere before the Big Bang just as there is nowhere south of the South Pole.

Life would be tragic if it weren't funny.

For years, my early work with Roger Penrose seemed to be a disaster for science. It showed that the universe must have begun with a singularity, if Einstein's general theory of relativity is correct. That appeared to indicate that science could not predict how the universe would begin.

It is no good getting furious if you get stuck. What I do is keep thinking about the problem but work on something else. Sometimes it is years before I see the way forward. In the case of information loss and black holes, it was 29 years.

While there's life, there is hope.

I believe in universal health care. And I am not afraid to say so.