When I was first diagnosed with ALS, I was given two years to live. Now 45 years later, I am doing pretty well.

At times, I get very lonely because people are afraid to talk to me or don't wait for me to write a response. I'm shy and tongue-tied at times. I find it difficult to talk to people who I don't know.

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.

Observations indicate that the universe is expanding at an ever increasing rate. It will expand forever, getting emptier and darker.

With genetic engineering, we will be able to increase the complexity of our DNA, and improve the human race. But it will be a slow process, because one will have to wait about 18 years to see the effect of changes to the genetic code.

Every man should marry. After all, happiness is not the only thing in life.

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.