The idea of 10 dimensions might sound exciting, but they would cause real problems if you forget where you parked your car.

Most sets of values would give rise to universes that, although they might be very beautiful, would contain no one able to wonder at that beauty.

To confine our attention to terrestrial matters would be to limit the human spirit.

I don't want to write an autobiography because I would become public property with no privacy left.

Look up at the stars, not down at your feet.

In the last 200 years the population of our planet has grown exponentially, at a rate of 1.9% per year. If it continued at this rate, with the population doubling every 40 years, by 2600 we would all be standing literally shoulder to shoulder.

When two's company, three's the result!