Stephen Hawking

There is no physical law precluding particles from being organised in ways that perform even more advanced computations than the arrangements of particles in human brains.

I have a full and satisfying life. My work and my family are very important to me.

There are too many accidents that can befall life on a single planet.

Obviously, because of my disability, I need assistance. But I have always tried to overcome the limitations of my condition and lead as full a life as possible. I have traveled the world, from the Antarctic to zero gravity.

All my adult life people have been helping me.

Imaginary time is a new dimension, at right angles to ordinary, real time.

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.

There are no black holes in the sense of regimes from which light can't escape to infinity.

Time travel was once considered scientific heresy, and I used to avoid talking about it for fear of being labelled a 'crank.'

As those who have seen Jurassic Park will know, this means a tiny disturbance in one place, can cause a major change in another. A butterfly flapping its wings can cause rain in Central Park, New York. The trouble is, it is not repeatable. The next time the butterfly flaps its wings, a host of other things will be different, which will also influence the weather. That is why weather forecasts are so unreliable.

Life on Earth is at the ever-increasing risk of being wiped out by a disaster, such as sudden global nuclear war, a genetically engineered virus or other dangers we have not yet thought of.

If we want to travel into the future, we just need to go fast. Really fast. And I think the only way we're ever likely to do that is by going into space.

We live in a bewildering world.

As a child, I wanted to know how things worked and to control them. With a friend, I built a number of complicated models that I could control.

As Irving Good realised in 1965, machines with superhuman intelligence could repeatedly improve their design even further, triggering what Vernor Vinge called a 'singularity.'

Some people would claim that things like love, joy and beauty belong to a different category from science and can't be described in scientific terms, but I think they can now be explained by the theory of evolution.

Our minds work in real time, which begins at the Big Bang and will end, if there is a Big Crunch - which seems unlikely, now, from the latest data showing accelerating expansion. Consciousness would come to an end at a singularity.

The doctor who diagnosed me with ALS, or motor neuron disease, told me that it would kill me in two or three years.

Wagner manages to convey emotion with music better than anyone, before or since.

Exploration by real people inspires us.

Time travel used to be thought of as just science fiction, but Einstein's general theory of relativity allows for the possibility that we could warp space-time so much that you could go off in a rocket and return before you set out.