I think my dad [ Stephen Hawking] would have been pleased if I had turned out a scientist because he truly believes that is the most interesting career open to anyone. But he also believes that you have to follow your own path in life and so he certainly wasn't going to push me toward theoretical physics when it didn't look like I was going in that direction naturally.

Think of our DNA. In the last million years, our DNA hasn't changed at all. It's really much the same as it was in the jungle, a million, two millions years ago. But in the last 200 years, our destructive capacities have increased many, many millions of times over. Why don't we see intelligent signals from outer space? Because in all likelihood, once the civilization reaches the point our civilization has reached, it destroys itself.

I think the human race doesn't have a future if we don't go into space. We need to expand our horizons beyond planet Earth if we are to have a long-term future. We cannot remain looking inward at ourselves on a small and increasingly polluted and overcrowded planet. We need to look outward to the wider universe.

Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global warming, nuclear war, a genetically engineered virus or other dangers. I think the human race has no future if it doesn't go into space. I therefore want to encourage public interest in space.

I think the next century will be the century of complexity.

I put a lot of effort into writing 'A Briefer History' at a time when I was critically ill with pneumonia because I think that it's important for scientists to explain their work, particularly in cosmology. This now answers many questions once asked of religion.

I think computer viruses should count as life,

Evolution has ensured that our brains just aren't equipped to visualise 11 dimensions directly. However, from a purely mathematical point of view it's just as easy to think in 11 dimensions, as it is to think in three or four.

I think the human race has no future if it doesn't go into space.