Stem cell research is the key to developing cures for degenerative conditions like Parkinson’s and motor neuron disease from which I and many others suffer. The fact that the cells may come from embryos is not an objection, because the embryos are going to die anyway.

While physics and mathematics may tell us how the universe began, they are not much use in predicting human behavior because there are far too many equations to solve. I’m no better than anyone else at understanding what makes people tick, particularly women.

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.

A few years ago, the city council of Monza, Italy, barred pet owners from keeping goldfish in curved bowls… saying that it is cruel to keep a fish in a bowl with curved sides because, gazing out, the fish would have a distorted view of reality. But how do we know we have the true, undistorted picture of reality?

If the rate of expansion one second after the Big Bang had been smaller by even one part in a hundred thousand million million, it would have recollapsed before it reached its present size. On the other hand, if it had been greater by a part in a million, the universe would have expanded too rapidly for stars and planets to form.

I think the brain is essentially a computer and consciousness is like a computer program. It will cease to run when the computer is turned off. Theoretically, it could be re-created on a neural network, but that would be very difficult, as it would require all one’s memories.compu

In my school, the brightest boys did math and physics, the less bright did physics and chemistry, and the least bright did biology. I wanted to do math and physics, but my father made me do chemistry because he thought there would be no jobs for mathematicians.

I was born on January 8, 1942, exactly three hundred years after the death of Galileo. I estimate, however, that about two hundred thousand other babies were also born that day. I don’t know whether any of them was later interested in astronomy.

If we do discover a complete theory, it should be in time understandable in broad principle by everyone. Then we shall all, philosophers, scientists, and just ordinary people be able to take part in the discussion of why we and the universe exist.

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.

In less than a hundred years, we have found a new way to think of ourselves. From sitting at the center of the universe, we now find ourselves orbiting an average-sized sun, which is just one of millions of stars in our own Milky Way galaxy.

In the past, there was active discrimination against women in science. That has now gone, and although there are residual effects, these are not enough to account for the small numbers of women, particularly in mathematics and physics.

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.

Although almost every theoretical physicist agrees with my prediction that a black hole should glow like a hot body, it would be very difficult to verify experimentally because the temperature of a macroscopic black hole is so low.

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.

It is generally recognised that women are better than men at languages, personal relations and multi-tasking, but less good at map-reading and spatial awareness. It is therefore not unreasonable to suppose that women might be less good at mathematics and physics.

The radiation left over from the Big Bang is the same as that in your microwave oven but very much less powerful. It would heat your pizza only to minus 271.3*C – not much good for defrosting the pizza, let alone cooking it.

I don’t have much positive to say about motor neuron disease, but it taught me not to pity myself because others were worse off, and to get on with what I still could do. I’m happier now than before I developed the condition.

When we understand string theory, we will know how the universe began. It won’t have much effect on how we live, but it is important to understand where we come from and what we can expect to find as we explore.

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.

The usual approach of science of constructing a mathematical model cannot answer the questions of why there should be a universe for the model to describe. Why does the universe go to all the bother of existing?

There is a real danger that computers will develop intelligence and take over. We urgently need to develop direct connections to the brain so that computers can add to human intelligence rather than be in opposition.

My advice to other disabled people would be, concentrate on things your disability doesn’t prevent you doing well, and don’t regret the things it interferes with. Don’t be disabled in spirit as well as physically.

I don’t think the human race will survive the next 1,000 years, unless we spread into space. There are too many accidents that can befall life on a single planet. But I’m an optimist. We will reach out to the stars.

Some forms of motor neuron disease are genetically linked, but I have no indication that my kind is. No other member of my family has had it. But I would be in favor of abortion if there was a high risk.

The whole history of science has been the gradual realization that events do not happen in an arbitrary manner, but that they reflect a certain underlying order, which may or may not be divinely inspired.

I think those who have a terminal illness and are in great pain should have the right to choose to end their own life, and those that help them should be free from prosecution.

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

We are in danger of destroying ourselves by our greed and stupidity. We cannot remain looking inwards at ourselves on a small and increasingly polluted and overcrowded planet.

Even if there is only one possible unified theory, it is just a set of rules and equations. What is it that breathes fire into the equations and makes a universe for them to describe?

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.

I regard the brain as a computer which will stop working when its components fail. There is no heaven or afterlife for broken down computers; that is a fairy story for people afraid of the dark.

My discovery that black holes emit radiation raised serious problems of consistency with the rest of physics. I have now resolved these problems, but the answer turned out to be not what I expected.

We must develop as quickly as possible technologies that make possible a direct connection between brain and computer, so that artificial brains contribute to human intelligence rather than opposing it.

I think computer viruses should count as life. I think it says something about human nature that the only form of life we have created so far is purely destructive. We’ve created life in our own image.

Science is beautiful when it makes simple explanations of phenomena or connections between different observations. Examples include the double helix in biology and the fundamental equations of physics.

Our population and our use of the finite resources of planet Earth are growing exponentially, along with our technical ability to change the environment for good or ill.

I believe everyone should have a broad picture of how the universe operates and our place in it. It is a basic human desire. And it also puts our worries in perspective.

Some scientists think it may be possible to capture a wormhole and enlarge it many trillions of times to make it big enough for a human or even a spaceship to enter.

We are just an advanced breed of monkeys on a minor planet of a very average star. But we can understand the Universe. That makes us something very special.

I would like nuclear fusion to become a practical power source. It would provide an inexhaustible supply of energy, without pollution or global warming.

In Britain, like most of the developed world, stem-cell research is regarded as a great opportunity. America will be left behind if it doesn’t change policy.

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.

The media need superheroes in science just as in every sphere of life, but there is really a continuous range of abilities with no clear dividing line.

Success in creating AI would be the biggest event in human history. Unfortunately, it might also be the last, unless we learn how to avoid the risks.

I believe the universe is governed by the laws of science. The laws may have been decreed by God, but God does not intervene to break the laws.

Look up at the stars and not down at your feet. Try to make sense of what you see, and wonder about what makes the universe exist. Be curious.

Science predicts that many different kinds of universe will be spontaneously created out of nothing. It is a matter of chance which we are in.

If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.

I have noticed even people who claim everything is predestined, and that we can do nothing to change it, look before they cross the road.

No one undertakes research in physics with the intention of winning a prize. It is the joy of discovering something no one knew before.

I think it quite likely that we are the only civilization within several hundred light years; otherwise we would have heard radio waves.

I believe alien life is quite common in the universe, although intelligent life is less so. Some say it has yet to appear on planet Earth.

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

I was never top of the class at school, but my classmates must have seen potential in me, because my nickname was Einstein.

I am just a child who has never grown up. I still keep asking these ‘how’ and ‘why’ questions. Occasionally, I find an answer.

We are all different. There is no such thing as a standard or run-of-the-mill human being, but we share the same human spirit.

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

There are grounds for cautious optimism that we may now be near the end of the search for the ultimate laws of nature.

The universe is governed by science. But science tells us that we can’t solve the equations, directly in the abstract.

Maybe I don’t have the most common kind of motor neuron disease, which usually kills in two or three years.

Many badly needed goals, like fusion and cancer cure, would be achieved much sooner if we invested more.

There is no heaven or afterlife for broken-down computers that is a fairy story for people afraid of the dark.

My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.

Even if it turns out that time travel is impossible, it is important that we understand why it is impossible.

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

Sometimes I wonder if I’m as famous for my wheelchair and disabilities as I am for my discoveries.

When one’s expectations are reduced to zero, one really appreciates everything one does have.

I don’t think the human race will survive the next thousand years unless we spread into space.

Philosophers have not kept up with modern developments in science. Particularly physics.

Because there is a law such as gravity, the universe can and will create itself from nothing.

If I had to choose a superhero to be, I would pick Superman. He’s everything that I’m not.

Scientists have become the bearers of the torch of discovery in our quest for knowledge.

However difficult life may seem, there is always something you can do and succeed at.

I think we have a good chance of surviving long enough to colonize the solar system.

God not only plays dice, but also sometimes throws them where they cannot be seen.

I want to know why the universe exists, why there is something greater than nothing.

Science is increasingly answering questions that used to be the province of religion.

I can’t disguise myself with a wig and dark glasses – the wheelchair gives me away.

I’m not afraid of death, but I’m in no hurry to die. I have so much I want to do first.

The past, like the future, is indefinite and exists only as a spectrum of possibilities.

Someone told me that each equation I included in the book would halve the sales.

There’s no way to remove the observer – us – from our perceptions of the world.

Only black holes of very low mass would emit a significant amount of radiation.

In my opinion, there is no aspect of reality beyond the reach of the human mind.

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

Science is not only a disciple of reason but, also, one of romance and passion.

Time can behave like another direction in space under extreme conditions.

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

People won’t have time for you if you are always angry or complaining.

There could be shadow galaxies, shadow stars, and even shadow people.galaxies

I think the human race doesn’t have a future if it doesn’t go into space.

Work gives you meaning and purpose and life is empty without it.

The universe is not indifferent to our existence – it depends on it.

It is not clear that intelligence has any long-term survival value.

One can’t predict the weather more than a few days in advance.

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

What I’d really like to control is not machines, but people.

A zero-gravity flight is a first step toward space travel.

One cannot really argue with a mathematical theorem.

I have so much that I want to do. I hate wasting time.

I believe things cannot make themselves impossible.

My work and my family are very important to me.

What was God doing before the divine creation?

We should seek the greatest value of our action.

No one can resist the idea of a crippled genius.

Among physicists, I’m respected I hope.

Life would be tragic if it weren’t funny.

I have wondered about time all my life.

Women. They are a complete mystery.

Intelligence is the ability to adapt to change.

Exploration by real people inspires us.

There is no unique picture of reality.

People who boast about their I.Q. are losers.

We live in a bewildering world.

Nothing cannot exist forever.