Stephen Hawking

“I regard [the many worlds interpretation] as self-evidently correct. [T.F.: Yet some don't find it evident to themselves.] Yeah, well, there are some people who spend an awful lot of time talking about the interpretation of quantum mechanics. My attitude — I would paraphrase Goering—is that when I hear of Schrödinger's cat, I reach for my gun.”

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

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

“I can't disguise myself with a wig and dark glasses - the wheelchair gives me away.”

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

“There ought to be something very special about the boundary conditions of the universe and what can be more special than that there is no boundary?”

“Theology is unnecessary.”

“What I have done is to show that it is possible for the way the universe began to be determined by the laws of science. In that case, it would not be necessary to appeal to God to decide how the universe began. This doesn't prove that there is no God, only that God is not necessary.”

“No one can resist the idea of a crippled genius.”

“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.”

“The fastest manned vehicle in history was Apollo 10. It reached 25,000 mph.”

“On seeing the Enterprise's warp engine while visiting the set of Star Trek: The Next Generation (where he would briefly play himself in the 1993 episode Descent, Part I), Hawking smiled and said: I'm working on that.”

“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.”

“So Einstein was wrong when he said, "God does not play dice." Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen.”

“My first popular book, 'A Brief History of Time,' aroused a great deal of interest, but many found it difficult to understand.”

“I don't believe that the ultimate theory will come by steady work along existing lines. We need something new. We can't predict what that will be or when we will find it because if we knew that, we would have found it already! It could come in the next 20 years, but we might never find it.”

“Up until the 1920s, everyone thought the universe was essentially static and unchanging in time.”

“The human race is just a chemical scum on a moderate-sized planet, orbiting around a very average star in the outer suburb of one among a hundred billion galaxies. We are so insignificant that I can't believe the whole universe exists for our benefit. That would be like saying that you would disappear if I closed my eyes.”

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

“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.”

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

“Life would be tragic if it weren't funny.”

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

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

“Einstein was confused, not the quantum theory.”

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

“All my life, I have been fascinated by the big questions that face us, and have tried to find scientific answers to them.”

“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.”

“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.”

“The world has changed far more in the past 100 years than in any other century in history. The reason is not political or economic but technological — technologies that flowed directly from advances in basic science.”

“All my adult life people have been helping me.”

“Although September 11 was horrible, it didn't threaten the survival of the human race, like nuclear weapons do.”

“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.”

“I don't think the human race will survive the next thousand 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.”

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

“We shouldn't be surprised that conditions in the universe are suitable for life, but this is not evidence that the universe was designed to allow for life. We could call order by the name of God, but it would be an impersonal God. There's not much personal about the laws of physics.”

“I had not expected 'A Brief History of Time' to be a best seller. It was my first popular book and aroused a great deal of interest. Initially, many people found it difficult to understand. I therefore decided to try to write a new version that would be easier to follow.”

“[on the possibility of contact with an alien civilization]: I think it would be a disaster. The extraterrestrials would probably be far in advance of us. The history of advanced races meeting more primitive people on this planet is not very happy, and they were the same species. I think we should keep our heads low.”

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

“I have no idea. People who boast about their IQ are losers.”

“It's time to commit to finding the answer, to search for life beyond Earth. Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures. It is important for us to know if we are alone in the dark.”

“Life would be tragic if it weren't funny.”

“If I had a time machine, I'd visit Marilyn Monroe in her prime or drop in on Galileo as he turned his telescope to the heavens.”

“I am discounting reports of UFOs. Why would they appear only to cranks and weirdos?”

“I first had the idea of writing a popular book about the universe in 1982. My intention was partly to earn money to pay my daughter's school fees.”

“My expectations were reduced to zero when I was 21. Everything since then has been a bonus.”

“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.”

“The life we have on Earth must have spontaneously generated itself. It must therefore be possible for life to generate spontaneously elsewhere in the universe.”

“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.”

“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.”

“The human race may be the only intelligent beings in the galaxy.”

“I think that it's important for scientists to explain their work, particularly in cosmology. This now answers many questions once asked of religion.”

“What I'd really like to control is not machines, but people.”

“It is a waste of time to be angry about my disability. One has to get on with life and I haven't done badly. People won't have time for you if you are always angry or complaining.”

“I can't say that my disability has helped my work, but it has allowed me to concentrate on research without having to lecture or sit on boring committees.”

“Equations are just the boring part of mathematics. I attempt to see things in terms of geometry.”

“Cambridge is one of the best universities in the world, especially in my field.”

“The victim should have the right to end his life, if he wants. But I think it would be a great mistake. However bad life may seem, there is always something you can do, and succeed at. While there's life, there is hope.”

“I have wanted to fly into space for many years, but never imagined it would really be feasible.”

“The downside of my celebrity is that I cannot go anywhere in the world without being recognized. It is not enough for me to wear dark sunglasses and a wig. The wheelchair gives me away.”

“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.”

“I'm not religious in the normal sense. 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.”

“You can't regulate every lab in the world.”

“Intelligence is the ability to adapt to change.”

“The zero-G part was wonderful and the higher-G part was no problem. I could have gone on and on. Space, here I come!”

“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.”

“In a world that is in chaos politically, socially and environmentally, how can the human race sustain another 100 years?”

“I entered the health care debate in response to a statement in the United States press in summer 2009 which claimed the National Health Service in Great Britain would have killed me off, were I a British citizen. I felt compelled to make a statement to explain the error.”

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

“Sometimes I wonder if I'm as famous for my wheelchair and disabilities as I am for my discoveries.”

“I imagine what happens to human consciousness when we die is much like turning off a computer. I don’t believe in a heaven for computers. I think the after-life is a fairy story for people afraid of the dark.”

“Throughout history, people have studied pure science from a desire to understand the universe rather than practical applications for commercial gain. But their discoveries later turned out to have great practical benefits.”

“There is a fundamental difference between religion, which is based on authority and science, which is based on observation and reason. Science will win, because it works.”

“We live in a bewildering world.”

“I have lived with the prospect of an early death for the last 49 years. I'm not afraid of death, but I'm in no hurry to die. I have so much I want to do first ... 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.”

“We lived in a tall, narrow Victorian house, which my parents had bought very cheaply during the war, when everyone thought London was going to be bombed flat. In fact, a V-2 rocket landed a few houses away from ours. I was away with my mother and sister at the time, but my father was in the house.”

“The Dreams that Stuff is Made of”

“Cosmology is a rapidly advancing field.”

“We should seek the greatest value of our action.”

“Most people don't have time to master the very mathematical details of theoretical physics.”

“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.”

“As scientists, we step on the shoulders of science, building on the work that has come before us - aiming to inspire a new generation of young scientists to continue once we are gone.”

“I used to think that information was destroyed in black holes. But the AdS/CFT correspondence led me to change my mind. This was my biggest blunder, or at least my biggest blunder in science.”

“I am in touch with a company that hopes to replicate my voice. However, they are not replicating my original voice - if they did that, I would sound like a man in his 20s, which would be very strange! They are actually trying to replicate the synthesizer that sits on my wheelchair.”

“Women. They are a complete mystery.”

“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.”

“The development of full artificial intelligence could spell the end of the human race. We cannot quite know what will happen if a machine exceeds our own intelligence, so we can't know if we'll be infinitely helped by it, or ignored by it and sidelined, or conceivably destroyed by it.”

“Perhaps one day I will go into space.”

“Black holes ain't as black as they are painted. They are not the eternal prisons they were once thought. Things can get out of a black hole, both to the outside, and possibly to another universe. So if you feel you are in a black hole, don't give up. There's a way out.”

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

“If machines produce everything we need, the outcome will depend on how things are distributed. Everyone can enjoy a life of luxurious leisure if the machine-produced wealth is shared, or most people can end up miserably poor if the machine-owners successfully lobby against wealth redistribution. So far, the trend seems to be toward the second option, with technology driving ever-increasing inequality.”

“I'm never any good in the morning. It is only after four in the afternoon that I get going.”

“Someone told me that each equation I included in the book would halve the sales. I therefore resolved not to have any equations at all. In the end, however, I did put in one equation, Einstein's famous equation, . I hope that this will not scare off half of my potential readers.”

“There are plenty of dead scientists I admire, but I can't think of any living ones. This is probably because it is only in retrospect that one can see who made the important contributions.”

“Bodies like the earth are not made to move on curved orbits by a force called gravity; instead, they follow the nearest thing to a straight path in a curved space, which is called a geodesic. A geodesic is the shortest (or longest) path between two nearby points.”

“I have found far greater enthusiasm for science in America than here in Britain. There is more enthusiasm for everything in America.”

“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 hope I have helped to raise the profile of science and to show that physics is not a mystery but can be understood by ordinary people.”

“Galileo, perhaps more than any other single person, was responsible for the birth of modern science.”

“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.”

“One could say: "The boundary condition of the universe is that it has no boundary." The universe would be completely self-contained and not affected by anything outside itself. It would neither be created nor destroyed. It would just BE.”

“Theoretical physics is one of the few fields in which being disabled is no handicap - it is all in the mind.”

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

“Just like a computer, we must remember things in the order in which entropy increases. This makes the second law of thermodynamics almost trivial. Disorder increases with time because we measure time in the direction in which disorder increases. You can’t have a safer bet than that!”

“What was God doing before the divine creation?”

“Sometimes I wonder if I'm as famous for my wheelchair and disabilities as I am for my discoveries.”

“Maybe that is our mistake: maybe there are no particle positions and velocities, but only waves. It is just that we try to fit the waves to our preconceived ideas of positions and velocities.The resulting mismatch is the cause of the apparent unpredictability.”

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

“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? 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?”

“Computers double their performance every month.”

“I believe the simplest explanation is, there is no God. No one created the universe and no one directs our fate. This leads me to a profound realization that there probably is no heaven and no afterlife either. We have this one life to appreciate the grand design of the universe and for that, I am extremely grateful.”

“If we do discover a complete theory, it should in time be understandable in broad principle by everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the discussion of the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason — for then we would know the mind of God.”

“The cyclic universe theory predicts no gravitational waves from the early universe.”

“Science could predict that the universe must have had a beginning.”

“I had not expected 'A Brief History of Time' to be a best seller.”

“Among physicists, I'm respected I hope.”

“When I gave a lecture in Japan, I was asked not to mention the possible re-collapse of the universe, because it might affect the stock market. However, I can re-assure anyone who is nervous about their investments that it is a bit early to sell: even if the universe does come to an end, it won't be for at least twenty billion years. By that time, maybe the GATT trade agreement will have come into effect.”

“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.”

“The Steady State theory was what Karl Popper would call a good scientific theory: it made definite predictions, which could be tested by observation, and possibly falsified. Unfortunately for the theory, they were falsified.”

“We think that life develops spontaneously on Earth, so it must be possible for life to develop on suitable planets elsewhere in the universe. But we don't know the probability that a planet develops life.”

“To show this diagram properly, I would really need a four dimensional screen. However, because of government cuts, we could manage to provide only a two dimensional screen.”

“My father was a research scientist in tropical medicine, so I always assumed I would be a scientist, too. I felt that medicine was too vague and inexact, so I chose physics.”

“The universe would have expanded in a smooth way from a single point. As it expanded, it would have borrowed energy from the gravitational field, to create matter. As any economist could have predicted, the result of all that borrowing, was inflation. The universe expanded and borrowed at an ever-increasing rate. Fortunately, the debt of gravitational energy will not have to be repaid until the end of the universe.”

“My three children have brought me great joy.”

“We hold these truths to be self-evident that all P-brains are created equal.”

“I don't care much for equations myself. This is partly because it is difficult for me to write them down, but mainly because I don't have an intuitive feeling for equations.”

“Life would be tragic if it weren't funny.”

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

“Mathematics is more than a tool and language for science. It is also an end in itself, and as such, it has, over the centuries, affected our worldview in its own right.”

“So next time someone complains that you have made a mistake, tell him that may be a good thing. Because without imperfection, neither you nor I would exist.”

“I entered the health care debate in response to a statement in the United States press in summer 2009 which claimed the National Health Service in Great Britain would have killed me off, were I a British citizen. I felt compelled to make a statement to explain the error.”

“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. … We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet.”

“Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going.”

“God not only plays dice, He also sometimes throws the dice where they cannot be seen.”

“We are each free to believe what we want and it is my view that the simplest explanation is there is no God. No one created the universe and no one directs our fate. This leads me to a profound realization. There is probably no heaven, and no afterlife either. We have this one life to appreciate the grand design of the universe, and for that, I am extremely grateful. (Quoted from the Discovery Channel, 15 August 2011.)”

“We are all different — but we share the same human spirit. Perhaps it's human nature that we adapt — and survive.”

“Life would be tragic if it weren't funny.”

“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.”

“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.”

“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.”

“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.”

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

“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.”

“Intelligence is the ability to adapt to change.”

“There is no unique 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.”

“We are all now connected by the Internet, like neurons in a giant brain.”

“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.”

“When one's expectations are reduced to zero, one really appreciates everything one does have.”

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

“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.”

“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.”

“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 believe things cannot make themselves impossible.”

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

“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 have noticed that even those who assert that everything is predestined and that we can change nothing about it still look both ways before they cross the street.”

“So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really completely self-contained, having no boundary or edge, it would have neither beginning nor end: it would simply be. What place, then, for a creator?”

“Not only does God play dice, but... he sometimes throws them where they cannot be seen.”

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

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

“My wife and I love each other very much.”

“Exploration by real people inspires us.”

“Although September 11 was horrible, it didn't threaten the survival of the human race, like nuclear weapons do.”

“I wouldn't be here today if it were not for the NHS. I have received a large amount of high-quality treatment without which I would not have survived.”

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

“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.”

“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.”

“To my mathematical brain, the numbers alone make thinking about aliens perfectly rational. The real challenge is to work out what aliens might actually be like.”

“It's time to commit to finding the answer, to search for life beyond Earth. Mankind has a deep need to explore, to learn, to know. We also happen to be sociable creatures. It is important for us to know if we are alone in the dark.”

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

“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?”

“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.”

“One cannot really argue with a mathematical theorem.”

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

“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.”

“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.”

“God may exist, but science can explain the universe without the need for a creator.”

“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.”

“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.”

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

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

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

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

“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.”

“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.”

“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.”

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

“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.”

“Life would be tragic if it weren't funny.”

“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.”

“Women. They are a complete mystery.”

“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.”

“People won't have time for you if you are always angry or complaining.”

“We are the product of quantum fluctuations in the very early universe.”

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

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

“We think we have solved the mystery of creation. Maybe we should patent the universe and charge everyone royalties for their existence.”

“Nothing cannot exist forever.”

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

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

“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 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.”

“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.”

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

“We should seek the greatest value of our action.”

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

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

“I don't have much positive to say about motor neurone disease. But it taught me not to pity myself because others were worse off, and to get on with what I could still do.”

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

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

“Why are we here? Where do we come from? Traditionally, these are questions for philosophy, but philosophy is dead.”

“The voice I use is a very old hardware speech synthesizer made in 1986. I keep it because I have not heard a voice I like better and because I have identified with it.”

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

“I'm an atheist.”

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

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

“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?”

“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.”

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

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

“People won't have time for you if you are always angry or complaining.”

“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.”

“Remember to 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. And however difficult life may seem, there is always something you can do and succeed at.”

“I have wondered about time all my life.”

“It's a pity that nobody has found an exploding black hole. If they had, I would have won a Nobel prize.”

“If you believe in science, like I do, you believe that there are certain laws that are always obeyed.”

“It was Einstein's dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein's day hadn't made enough progress in understanding the forces of nature for that to be a realistic goal.”

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

“Not only does God play dice, but... he sometimes throws them where they cannot be seen.”

“There's no way to remove the observer - us - from our perceptions of the world.”

“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.”

“God not only plays dice, He also sometimes throws the dice where they cannot be seen.”

“The missing link in cosmology is the nature of dark matter and dark energy.”

“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 favour of abortion if there was a high risk.”

“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.'”

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

“My work and my family are very important to me.”

“The universe is not indifferent to our existence - it depends on it.”

“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.”

“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.”

“Many people find the universe confusing - it's not.”

“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.”

“If you understand the universe, you control it, in a way.”

“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.”

“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.”

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

“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?”

“I don't think the human race will survive the next thousand years, unless we spread into space.”

“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.”

“The most incomprehensible thing about the universe is that it is comprehensible. —ALBERT EINSTEIN”

“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.”

“Science can lift people out of poverty and cure disease. That, in turn, will reduce civil unrest.”

“My wife and I love each other very much.”

“I grew up thinking that a research scientist was a natural thing to be.”

“I have visited Japan several times and have always been shown wonderful hospitality.”

“Before I lost my voice, it was slurred, so only those close to me could understand, but with the computer voice, I found I could give popular lectures. I enjoy communicating science. It is important that the public understands basic science, if they are not to leave vital decisions to others.”

“I want my books sold on airport bookstalls.”

“I was not a good student. I did not spend much time at college; I was too busy enjoying myself.”

“We only have to look at ourselves to see how intelligent life might develop into something we wouldn't want to meet.”

“I believe things cannot make themselves impossible.”

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

“M-theory is the unified theory Einstein was hoping to find.”

“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.”

“Before we understand science, it is natural to believe that God created the universe.”

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

“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.”

“... might suggest that the so-called imaginary time is really the real time, and that what we call real time is just a figment of our imaginations. In real time, the universe has a beginning and an end at singularities that form a boundary to space-time and at which the laws of science break down. But in imaginary time, there are no singularities or boundaries. So maybe what we call imaginary time is really more basic, and what we call real is just an idea that we invent to help us describe what we think that universe is like. (....) a scientific theory is just a mathematical model we make to describe our observations: it exists only in our minds. So it is meaningless to ask: which is real, 'real' or 'imaginary' time? It is simply a matter of which is the more useful description.”

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

“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.”

“Before 1915, space and time were thought of as a fixed arena in which events took place, but which was not affected by what happened in it. Space and time are now dynamic quantities... space and time not only affect but are also affected by everything that happens in the universe.”

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

“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 enjoy all forms of music - pop, classical and opera.”

“'The Simpsons' appearances were great fun. But I don't take them too seriously. I think 'The Simpsons' have treated my disability responsibly.”

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

“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 doesn't have a future if it doesn't go into space.”

“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.”

“Keeping an active mind has been vital to my survival, as has been maintaining a sense of humor.”

“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.”

“One can't predict the weather more than a few days in advance.”

“The Planck satellite may detect the imprint of the gravitational waves predicted by inflation. This would be quantum gravity written across the sky.”

“It was Einstein's dream to discover the grand design of the universe, a single theory that explains everything. However, physicists in Einstein's day hadn't made enough progress in understanding the forces of nature for that to be a realistic goal.”

“According to 'M' theory, ours is not the only universe. Instead, 'M' theory predicts that a great many universes were created out of nothing.”

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

“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.”

“My ideal role would be a baddie in a James Bond film. I think the wheelchair and the computer voice would fit the part.”

“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.”

“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 believe there are no questions that science can't answer about a physical universe.”

“Among physicists, I'm respected I hope.”

“God is the name people give to the reason we are here. But I think that reason is the laws of physics rather than someone with whom one can have a personal relationship. An impersonal God.”

“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 the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe.”

“I used to think information was destroyed in black hole. This was my biggest blunder, or at least my biggest blunder in science.”

“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.”

“Earth might one day soon resemble the planet Venus.”

“Intelligence is the ability to adapt to change.”

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

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

“The Paralympic Games is about transforming our perception of the world.”

“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.”

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

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

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

“I had a bet with Gordon Kane of Michigan University that the Higgs particle wouldn't be found.”

“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.”

“There is nothing bigger or older than the universe.”

“It now appears that the way the universe began can indeed be determined, using imaginary time.”

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

“To my mathematical brain, the numbers alone make thinking about aliens perfectly rational. The real challenge is to work out what aliens might actually be like.”

“Using e-mail, I can communicate with scientists all over the world.”

“Keeping an active mind has been vital to my survival, as has been maintaining a sense of humor.”

“It is extremely important to me to write for children.”