Quotes by Stephen Hawking

There is a very real danger that we will kill everything on this planet now that we have the technological power to do so. 

Though we feel we can choose what we do, our understanding of the molecular basis of biology shows that biological processes are governed by the laws of physics and chemistry and therefore are as determined as the orbits of the planets. 

When I hear of Schrodinger’s cat, I reach for my pistol. 

If what we regard as real depends on our theory, how can we make reality the basis of our philosophy? …But we cannot distinguish what is real about the universe without a theory…it makes no sense to ask if it corresponds to reality, because we do not know what reality is independent of a theory. 

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. 

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. 

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. 

The initial configuration of the universe may have been chosen by God, or it may itself have been determined by the laws of science. In either case, it would seem that everything in the universe would then be determined by evolution according to the laws of science, so it is difficult to see how we can be masters of our fate. 

The intelligent beings in these regions should therefore not be surprised if they observe that their locality in the universe satisfies the conditions that are necessary for their existence. It is a bit like a rich person living in a wealthy neighborhood not seeing any poverty. 

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

All that my work has shown is that you don’t have to say that the way the universe began was the personal whim of God. 

Speech has allowed the communication of ideas, enabling human beings to work together to build the impossible. Mankind’s greatest achievements have come about by talking, and its greatest failures by not talking. It doesn’t have to be like this. Our greatest hopes could become reality in the future. With the technology at our disposal, the possibilities are unbounded. All we need to do is make sure we keep talking. 

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. 

All of my life, I have been fascinated by the big questions that face us, and have tried to find scientific answers to them. If, like me, you have looked at the stars, and tried to make sense of what you see, you too have started to wonder what makes the universe exist. 

A lot of prizes have been awarded for showing the universe is not as simple as we might have thought. 

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. Clearly, no scientist better represents those advances than Albert Einstein: TIME’s Person of the Century. 

We won’t know for a few years. 

I think the next [21st] century will be the century of complexity. We have already discovered the basic laws that govern matter and understand all the normal situations. We don’t know how the laws fit together, and what happens under extreme conditions. But I expect we will find a complete unified theory sometime this century. The is no limit to the complexity that we can build using those basic laws. 

What could define God, [is thinking of God] as the embodiment of the laws of nature. However, this is not what most people would think of that God. They made a human-like being with whom one can have a personal relationship. When you look at the vast size of the universe and how insignificant an accidental human life is in it, that seems most impossible. 

One does not have to appeal to God to set the initial conditions for the creation of the universe, but if one does He would have to act through the laws of physics. 

The universe and the Laws of Physics seem to have been specifically designed for us. If any one of about 40 physical qualities had more than slightly different values, life as we know it could not exist: Either atoms would not be stable, or they wouldn’t combine into molecules, or the stars wouldn’t form heavier elements, or the universe would collapse before life could develop, and so on… 

You cannot predict the future. 

Or in other words, why does disorder increase in the same direction of time as that in which the universe expands? 

I believe that the long-term future of the human race must be space and that it represents an important life insurance for our future survival, as it could prevent the disappearance of humanity by colonizing other planets, 

The human failing I would most like to correct is aggression, 

I do not believe in a personal God. 

science will win because it works. 

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. 

It often happens that I have an idea, but then I try to fill in the intermediate steps and find they don’t work, so I have to give it up. 

Someone told me that each equation I included in my book would halve the sales. I did put in one equation, Einstein’s famous equation, E = MC squared. I hope that this will not scare off half of my potential readers. 

Why do we remember the past, but not the future? 

There is no way that we can predict the weather six months ahead beyond giving the seasonal average 

Physics as we know it will be over in six months – Max Born 

It’s the gravity that shapes the large scale structure of the universe, even though it is the weakest of four categories of forces 

In his eyes shone the reflection of the most beautiful planet in the Universe-a planet that is not too hot and not too cold; that has liquid water on the surface and where the gravity is just right for human beings and the atmosphere is perfect for them to breathe; where there are mountains and deserts and oceans and islands and forests and trees and birds and plants and animals and insects and people-lots and lots of people. Where there is life. Some of it, possibly, intelligent. 

I have experimental evidence that time travel is not possible. 

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. 

Simplicity is a matter of taste 

Scientists tend to risk theories they admire 

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

We believe human begins have existed for only a small fraction of cosmic history, because human race has been improving so rapidly in knowledge and technology that if people had been around for millions of years, the human race would be much further along in it’s mastery. 

If you are lucky enough to find love, remember it is there and don’t throw it away. 

Because imaginary time behaves like another direction in space, histories in imaginary time can be closed surfaces, like the surface of the Earth, with no [existential] beginning or end. 

God not only plays dice, he throws them in the corner where you can’t see them. 

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. 

The human capacity for guilt is such that people can always find ways to blame themselves 

We each exist for but a short time, and in that time explore but a small part of the whole universe 

So when people ask me if I believe God created the universe, I tell them that the question itself makes no sense. Time didn’t exist before the Big Bang, so there is no time for God to make the universe in. It’s like asking for directions to the edge of the earth; the earth is a sphere, it doesn’t have an edge, so looking for it is a futile exercise. 

Quiet people have the loudest minds. 

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. It matters that you don’t just give up. 

I’m the archetype of a disabled genius, or should I say a physically challenged genius, to be politically correct. At least I’m obviously physically challenged. Whether I’m a genius is more open to doubt. 

While there’s life, there is hope. 

Eternity is a long time, especially towards the end. 

We don’t let animals suffer, so why humans? 

Not to leave planet Earth would be like castaways on a desert island not trying to escape…Sending humans to other planets … will shape the future of the human race in ways we don’t yet understand, and may determine whether we have any future at all. 

The human race shouldn’t have all its eggs in one basket, or on one planet. Let’s hope we can avoid dropping the basket until we have spread the load. 

Although quantum mechanics has been around for nearly 70 years, it is still not generally understood or appreciated, even by those that use it to do calculations. 

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. 

The universe does not behave according to our pre-conceived ideas. It continues to surprise us. 

If there really is a complete unified theory that governs everything, it presumably also determines your actions. But it does so in a way that is impossible to calculate for an organism that is as complicated as a human being. The reason we say that humans have free will is because we can’t predict what they will do. 

The human failing I would most like to correct is aggression. It may have had survival advantage in caveman days, to get more food, territory or partner with whom to reproduce, but now it threatens to destroy us all. 

We find ourselves in a bewildering world. We want to make sense of what we see around us and to ask: What is the nature of the universe? What is our place in it and where did it and we come from? Why is it the way it is? 

Disability need not be an obstacle to success. 

I would rather be right than rigorous. 

The Simpsons is the best thing on American television. 

If it [the universe] was expanding fairly slowly, the force of gravity would cause it eventually to stop expanding and then to start contracting. However, if it was expanding at more than a certain critical rate, gravity would never be strong enough to stop it, and the universe would continue to expand forever. 

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

Many people do not like the idea that time has a beginning, probably because it smacks of divine intervention. 

Thirty years ago I was diagnosed with motor neurone disease, and given two and a half years to live. I have always wondered how they could be so precise about the half. 

I have sold more books on physics than Madonna has on sex. [Hawking adopted this statement from a remark made to him by his former post-doc, Nathan Myhrvold.] 

[Question: Do you feel that scientists correct themselves as often as they should?] More often than politicians, but not as often as they should. 

[Question: What do you think was the most important physics idea to emerge this year?] We won’t know for a few years. 

It is reasonable to ask who or what created the universe, but if the answer is God, then the question has merely been deflected to that of who created God. 

I am damned if I’m going to die before I have unraveled more of the universe 

Humanities deepest desire for knowledge is justification enough for continuing our quest. and our goal is nothing less than a complete description of the universe we live in. 

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

There is no prescribed route to follow to arrive at a new idea. You have to make the intuitive leap. 

If you understand how the universe operates, you control it in a way. 

Only a very few would allow creatures like us to exist. Thus our presence selects out from this vast array only these universes that are compatible without existence. Although we are puny and insignificant on the scale of the cosmos, this makes us in a sense, the lords of creation. 

It is impossible to imagine a four-dimensional space. I personally find it hard enough to visualize a three-dimensional space! 

There are no black holes – in the sense of regimes from which light can’t escape to infinity. There are however apparent horizons which persist for a period of time. 

One of the basic rules of the universe is that nothing is perfect. Perfection simply doesn’t exist…..Without imperfection, neither you nor I would exist 

Ever since the dawn of civilization, people have not been content to see events as unconnected and inexplicable. They have craved an understanding of the underlying order in the world. Today we still yearn to know why we are here and where we came from. Humanity’s deepest desire for knowledge is justification enough for our continuing quest. And our goal is nothing less than a complete description of the universe we live in. 

Although I cannot move and I have to speak through a computer, in my mind I am free. 

Please join me in applauding the ESA – European Space Agency’s historic efforts with the Rosetta Mission and landing a spacecraft on rotating comet. It may seem like a work of fiction, but it is very real, very impressive, and will help us to further uncover the mysteries surrounding the formation of the solar system. They made a beautiful short film using an imaginary landscape to illustrate today’s historic feat. 

It [AI] would take off on its own and redesign itself at an ever increasing rate. Humans, who are limited by slow biological evolution, couldn’t compete and would be superseded. 

It’s clearly possible for a something to acquire higher intelligence than its ancestors: we evolved to be smarter than our ape-like ancestors, and Einstein was smarter than his parents. 

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. 

A picture is worth a thousand words…and uses up a thousand times the memory. 

Doing a job RIGHT the first time gets the job done. Doing the job WRONG fourteen times gives you job security. 

A person who smiles in the face of adversity…probably has a scapegoat. 

Plagiarism saves time. 

If at first you don’t succeed, try management. 

TEAMWORK…means never having to take all the blame yourself. 

The beatings will continue until morale improves. 

We waste time, so you don’t have to. 

Hang in there, retirement is only thirty years away! 

Go the extra mile. It makes your boss look like an incompetent slacker. 

A snooze button is a poor substitute for no alarm clock at all. 

When the going gets tough, the tough take a coffee break. 

Succeed in spite of management. 

To understand recursion, one must first understand recursion. 

Perhaps we could write code to optimize code, then run that code through the code optimizer? 

Money is not everything. There’s Master card & Visa. 

One should love animals. They are so tasty. 

Save water. Shower with your girlfriend. 

Love the neighbor. But don’t get caught. 

Every man should marry. After all, happiness is not the only thing in life. 

The wise never marry, and when they marry they become otherwise. 

Success is a relative term. It brings so many relatives. 

Never put off the work till tomorrow what you can put off today. 

Children in backseats cause accidents. Accidents in backseats cause children. 

There should be a better way to start a day than waking up every morning. 

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

The more you learn, the more you know. The more you know, the more you forget. The more you forget, the less you know. So why bother to learn. 

Once I wept for I had no shoes. Then I met a man with no feet, so I took his shoes. I mean, it wasn’t as if he was going to need them. 

I may contradict myself, but at least I don’t contradict myself. 

I’m really easy to get along with once you see it my way. 

The fact that no one understands you doesn’t mean you’re an artist. 

The human race does not have a very good record of intelligent behavior. 

Do you ever wonder how much deeper the ocean would be without sponges? 

Nothing is fool-proof to a sufficiently talented fool. 

If you lined up all the cars in the world end to end, someone would try to pass them. 

Latest survey shows that 3 out of 4 people make up 75% of the world’s population. 

It was recently discovered that research causes cancer in rats. 

I’d say I don’t believe in God, but I’m afraid He might hear me. 

I don’t fear God- I fear His believers… 

Half the battle is just showing up. 

Jesus loves you, but everyone else thinks you’re an ass. 

When something is made idiot proof, they will just make better idiots. 

When I get to heaven I’m gonna find the guy in charge of the weather and kick his rear. 

Do you believe in first love – or should I pass by again? 

So great a contribution to physics was Two New Sciences that scholars have long maintained that the book anticipated Isaac Newton’s laws of motion. 

Maxwell is the physicist’s physicist. 

We explore because we are human. 

Please join me in applauding the ESA – European Space Agency’s historic efforts with the Rosetta Mission and landing a spacecraft on rotating comet. It may seem like a work of fiction, but it is very real, very impressive, and will help us to further uncover the mysteries surrounding the formation of the solar system. They made a beautiful short film using an imaginary landscape to illustrate today’s historic feat. 

We only have to look at ourselves to see how intelligent life might develop into something we wouldnt want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach, 

I think computer viruses should count as life, 

It matters that you don’t just give up, 

What was God doing before the divine creation? Was he preparing hell for people who asked such questions? 

Before we understand science, it is natural to believe that God created the universe. But now science offers a more convincing explanation. 

What is important is that we have the ability to create. 

What I meant by ‘we would know the mind of God’ is, we would know everything that God would know, if there were a God. Which there isn’t. I’m an atheist. 

The development of full artificial intelligence could spell the end of the human race. 

Religion believes in miracles, but these aren’t compatible with science. 

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. But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million. Our only chance of long term survival, is not to remain inward looking on planet Earth, but to spread out into space. 

The increase of disorder or entropy is what distinguishes the past from the future, giving a direction to time. 

I like physics, but I love cartoons. 

If one is physically disabled, one cannot afford to be *psychologically* disabled as well. 

A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations. 

Why does the universe go to all the bother of existing? 

A million million million million (1 with twenty-four zeros after it) miles, the size of the observable universe. 

If time travel is possible, where are the tourists from the future? 

The rate of progress is so rapid that what one learns at school or university is always a bit out of date. Only a few people can keep up with the rapidly advancing frontier of knowledge, and they have to devote their whole time to it and specialize in a small area. The rest of the population has little idea of the advances that are being made or the excitement they are generating. 

Mankind’s greatest achievements have come about by talking and its greatest failures by not talking. It doesn’t have to be like this. 

Nothing is better than reading and gaining more and more knowledge. 

The thing about smart people is that they seem like crazy people to dumb people. 

If the government is covering up knowledge of aliens, they are doing a better job of it than they do at anything else. 

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. 

Disorder increases with time because we measure time in the direction in which disorder increases. 

The laws of science do not distinguish between the past and the future. 

All the evidence shows that God was actually quite a gambler, and the universe is a great casino, where dice are thrown, and roulette wheels spin on every occasion. Over a large number of bets, the odds even out and we can make predictions; that’s why casino owners are so rich. But over a very small number of rolls of the dice, the uncertainty principle is very important. 

I’m the archetype of a disabled genius, or should I say a physically challenged genius, to be politically correct. At least I’m obviously physically challenged. Whether I’m a genius is more open to doubt. 

Is god omnipotent ? If he is, can he create a rock so heavy he can’t lift it ? 

We live in the most probable of all possible worlds. 

Science can explain the universe without the need for a Creator. 

In A Brief History Of Time I used the word “God” like Einstein did as a shorthand for the laws of physics. However, this is not what most people mean by God, so I have decided not to use the term. The laws of physics can explain the universe without the need for a God. 

People think I’m a Simpsons character. 

Many badly needed goals, like fusion and cancer cure, would be achieved much sooner if we invested more [in scientific education and research]. 

If I have questions about the universe on my mind when I go to bed, I can’t turn off. I dream equations all night. 

It should soon be possible dramatically to increase the intelligence and life span of a few individuals [with the help of genetic engineering]. They and their offspring could become a master race. Evolution pays no regard to social justice. It was not fair on the Neanderthals they were replaced by modern humans. 

If any one of about 40 physical qualities had more than slightly different values, life as we know it could not exist… 

It matters if you don’t just give up. 

It surprises me how disinterested we are today about things like physics, space, the universe and philosophy of our existence, our purpose, our final destination. Its a crazy world out there. Be curious. 

In this way, Edwin Hubble worked out the distances to nine different galaxies. We now know that our galaxy is only one of some hundred thousand million that can be seen using modern telescopes, each galaxy itself containing some hundred thousand million stars. 

Many people do not like the idea that time has a beginning, probably because it smacks of divine intervention. (The Catholic Church, on the other hand, seized on the big bang model and in 1951 officially pronounced it to be in accordance with the Bible. 

What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise. 

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. 

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. 

One, remember to look up at the stars and not down at your feet. Two, never give up work. Work gives you meaning and purpose and life is empty without it. Three, if you are lucky enough to find love, remember it is there and don’t throw it away. 

What I have learned from life is to make the most of what you have got. 

Real science can be far stranger than science fiction and much more satisfying. 

Of course it is possible that UFO’s really do contain aliens as many people believe, and the government is hushing it up 

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

If the total energy of the universe must always remain zero, and it costs energy to create a body, how can a whole universe be created from nothing? 

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

If everything in the universe depends upon everything else in a fundamental way, it might be impossible to get close to a full solution by investigating parts of the problem in isolation. 

Some individuals are better able than others to draw the right conclusions about the world about them and act accordingly. These individuals will be more likely to survive and reproduce so their pattern of behaviour and thought will become dominant 

If it were only a few degrees, that would be serious, but we could adapt to it. But the danger is the warming process might be unstable and run away. We could end up like Venus, covered in clouds and with the surface temperature of 400 degrees. It could be too late if we wait until the bad effects of warming become obvious. We need action now to reduce emission of carbon dioxide. 

One can see from space how the human race has changed the Earth. Nearly all of the available land has been cleared of forest and is now used for agriculture or urban development. The polar icecaps are shrinking and the desert areas are increasing. At night, the Earth is no longer dark, but large areas are lit up. All of this is evidence that human exploitation of the planet is reaching a critical limit. But human demands and expectations are ever-increasing. We cannot continue to pollute the atmosphere, poison the ocean and exhaust the land. There isn’t any more available. 

The meaning in life is not out there but inbetween our ears. In many ways this makes us the lords of creation. 

The progress of the human race in understanding the universe has established a small corner of order in an increasingly disordered universe. 

There could be whole antiworlds and antipeople made out of antiparticles. However, if you ever meet your antiself, don’t shake hands! You would both vanish in a great flash of light. 

This required abandoning the idea that there is a universal quantity called time that all clocks measure. Instead, everyone would have his own personal time. The clocks of two people would agree if they were at rest with respect to each other but not if they were moving. This has been confirmed by a number of experiments, including one in which an extremely accurate timepiece was flown around the world and then compared with one that had stayed in place. If you wanted to live longer, you could keep flying to the east so the speed of the plane added to the earth 

[On President Bush’s plan to get to Mars in 10 years] Stupid. Robots would do a better job and be much cheaper because you don’t have to bring them back. 

The large-scale homogeneity of the universe makes it very difficult to believe that the structure of the universe is determined by anything so peripheral as some complicated molecular structure on a minor planet orbiting a very average star in the outer suburbs of a fairly typical galaxy. 

If we can avoid disaster for the next two centuries, our species should be safe as we spread into space. If we are the only intellegent beings in the galaxy we should make sure we survive and continue. . . . Our only chance of long-term survival is not to remain inward looking on planet Earth but to spread out into space. We have made remarkable progress in the last hundred years. But if we want to continue beyond the next hundred years, our future is in space. 

We are very, very small, but we are profoundly capable of very, very big things 

Issuing an insurance policy against abduction by aliens seems a pretty safe bet. 

If human life were long enough to find the ultimate theory, everything would have been solved by previous generations. Nothing would be left to be discovered. 

“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,”By contrast, computers double their speed and memories every 18 months. 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.” 

“Sooner or later disasters such as an asteroid collision or a nuclear war could wipe us all out, But once we spread out into space and establish independent colonies, our future should be safe.” 

Then we shall… 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. 

I’ve noticed that even people who believe in fate look both ways before crossing the street. 

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. 

Maybe I’m being a bit harsh on philosophers, but they have not been very kind to me… I have been variously called nominalist, an instrumentalist, a positivist, a realist, and several other ists. The technique seems refutation by denigration: If you can attach a label to my approach, you don’t have to say what is wrong with it… I am sure that Einstein, Heisenberg and Dirac didn’t worry about whether they were realists or instrumentalists. 

Science does not deny religion, it just offers a simpler alternative. 

Its a crazy world out there. Be curious. 

Don’t be disabled in spirit as well as physically. 

Scientific discovery may not be better than sex, but the satisfaction lasts longer. 

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

It is all right to make mistakes; nothing is perfect because with perfection, we would not exist. 

We are only the temporary custodians of the particles which we are made of. They will go on to lead a future existence in the enormous universe that made them 

I don’t know what my IQ is. People who gloat about their IQ’s are losers 

We are entering an increasingly dangerous period of our history. But I’m an optimist. 

The boundary condition of the universe is that it has no boundary. 

As we shall see, the concept of time has no meaning before the beginning of the universe. This was first pointed out by St. Augustine. When asked: What did God do before he created the universe? Augustine didn’t reply: He was preparing Hell for people who asked such questions. Instead, he said that time was a property of the universe that God created, and that time did not exist before the beginning of the universe. 

One can imagine that God created the universe at literally any time in the past. On the other hand, if the universe is expanding, there may be physical reasons why there had to be a beginning. One could imagine that God created the universe at the instant of the big bang, or even afterwards in just such a way as to make it look as though there had been a big bang, but it would be meaningless to suppose that it was created before the big bang. An expanding universe does not preclude a creator, but it does place limits on when he might have carried out his job! 

The question is: is the way the universe began chosen by God for reasons we can’t understand, or was it determined by a law of science? I believe the second. If you like, you can call the laws of science ‘God’, but it wouldn’t be a personal God that you could meet, and ask questions. 

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 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. 

When I was first diagnosed with ALS, I was given two years to live. Now 45 years later, I am doing pretty well. 

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? 

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! 

For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imagination. We learned to talk and we learned to listen. 

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’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. 

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. 

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. 

I think [contacting an alien civilization] 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. 

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

We see the universe the way it is because we exist. 

One might think this means that imaginary numbers are just a mathematical game having nothing to do with the real world. From the viewpoint of positivist philosophy, however, one cannot determine what is real. All one can do is find which mathematical models describe the universe we live in. It turns out that a mathematical model involving imaginary time predicts not only effects we have already observed but also effects we have not been able to measure yet nevertheless believe in for other reasons. So what is real and what is imaginary? Is the distinction just in our minds? 

It is said that there’s no such thing as a free lunch. But the universe is the ultimate free lunch. 

A model is a good model if first it interprets a wide range of observations in terms of a simple and elegant model, and second if the model makes definite predictions that can be tested, and possibly falsified, by observation. 

I think the universe was spontaneously created out of nothing, according to the laws of science. It has no beginning and no end. 

Observations indicate that the universe is expanding at an ever-increasing rate. It will expand forever, getting emptier and darker. Although the universe doesn’t have an end, it had a beginning in the Big Bang. One might ask what is before that but the answer is that there is nowhere before the Big Bang just as there is nowhere south of the South Pole. 

If we ever do find a complete theory of the universe, it would be a great triumph of human reason but it wouldn’t leave much for us to do. We need an intellectual challenge. 

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. 

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

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

To my mathematical brain, the numbers alone make thinking about aliens perfectly rational, 

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

What lies north of the North Pole? 

The real challenge is to work out what aliens might actually be like. 

If a superior alien civilization sent us a message saying, ‘We’ll arrive in a few decades’, would we just reply, ‘OK, call us when you get here – we’ll leave the lights on’? Probably not – but this is more or less what is happening with AI, 

I wouldnt 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. 

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 

It would be very difficult to explain why the universe should have begun in just this way, except as the act of a God who intended to create beings like us 

To boldly go where no one has gone before 

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! 

Our only chance of long-term survival is not to remain lurking on planet Earth, but to spread out into space. 

There should be no boundaries to human endeavor. However bad life may seem, there is always hope. 

I thought Eddie Redmayne portrayed me very well… At times I thought he was me. 

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

Only time – whatever that may be – will tell. 

Unless mankind redesigns itself by changing our DNA through altering our genetic makeup, computer-genera ted robots will take over our world. 

We have made remarkable progress in the last hundred years, but if we want to continue, our future is in space. 

Science is beautiful when it makes simple explanations of phenomena or connections between different observations. 

I believe in the possible. I believe, small though we are, insignificant though we may be, we can reach a full understanding of the universe. You were right when you said you felt small, looking up at all that up there. We are very, very small, but we are profoundly capable of very, very big things. 

One can’t prove that God doesn’t exist, but science makes God unnecessary. The laws of physics can explain the universe without the need for a creator. 

The concern here is that financial services become a kind of tech-led Wild West. 

You may see a cup of tea fall off a table and break into pieces on the floor… But you will never see the cup gather itself back together and jump back on the table. The increase of disorder, or entropy, is what distinguishes the past from the future, giving a direction to time. 

Computer viruses are alive. 

We go about our daily lives understanding almost nothing of the world. 

Gravity is so strong that space is bent round onto itself, making it rather like the surface of the earth. If one keeps traveling in a certain direction on the surface of the earth, one never comes up against an impassable barrier or falls over the edge, but eventually comes back to where one started. 

Now, radical forward thinking is offering hope for the future: Replacement body parts to order. A team of scientists in California believe that if you can design them on a computer, you should be able to print them out. 

We’ve created life in our own image. 

The laws of science, as we know them at present, contain many fundamental numbers, like the size of the electric charge of the electron and the ratio of the masses of the proton and the electron …. The remarkable fact is that the values of these numbers seem to have been finely adjusted to make possible the development of life. 

Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. 

The “Powers That Be” are not smart enough to engineer Armageddon, but they may yet be stupid enough. If governments are involved in covering up the knowledge of aliens, then they are doing a much better job of it than they seem to do at anything else. 

There is a real danger that computers will develop intelligence and take over. 

Over a very small number of rolls of the dice, the uncertainty principle is very important. 

I’m here to chew gum and kick some ass, and I’m all out of gum. 

In my mind, I am free. 

One could imagine such technology outsmarting financial markets, out-inventing human researchers, out-manipulating human leaders, and developing weapons we cannot even understand. 

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. 

But a machine that was powerful enough to accelerate particles to the grand unification energy would have to be as big as the Solar System – and would be unlikely to be funded in the present economic climate. 

If I knew what was going to happen in ten years I would do it now. I just follow my nose. 

At times, I get very lonely because people are afraid to talk to me or don’t wait for me to write a response. I’m shy and tongue-tied at times. I find it difficult to talk to people who I don’t know. 

Disability can be no handicap. 

I’m very interested in film making. It’s telling a story, fiction or non-fiction. I have been filmed quite a lot. Contrary to popular belief, filming isn’t glamorous. It can be wearingly repetitious, as the same shot is taken over and over again. 

Time travel may be possible, but it is not practical. 

Chaos, when left alone, tends to multiply. 

It is tribute to how far we have come in theoretical physics that it now takes enormous machines and a great deal of money to perform experiments whose results we can not predict. 

The moment you understand the whole Universe, is the moment you slightly begin to understand the way God’s mind works 

In effect, we have redefined the task of science to be the discovery of laws that will enable us to predict events up to the limits set by the uncertainty principle. 

For millions of years, mankind lived just like the animals. Then something happened which unleashed the power of our imaginations, we learned to talk. 

Not only does God play dice with the Universe – he sometimes casts them where they can’t be seen. 

The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge. 

My publisher told me that the number of readers of this book will be inversely proportional to the number of equations it contains. 

A well-known scientist (some say it was Bertrand Russell) once gave a public lecture on astronomy. He described how the earth orbits around the sun and how the sun, in turn, orbits around the center of a vast collection of stars called our galaxy. At the end of the lecture, a little old lady at the back of the room got up and said: ‘What you have told us is rubbish. The world is really a flat plate supported on the back of a giant tortoise.’ The scientist gave a superior smile before replying, ‘What is the tortoise standing on?’ ‘You’re very clever, young man, very clever,’ said the old lady. ‘But it’s turtles all the way down! 

If we do discover a complete theory [of the universe], 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. 

What is it that breathes fire into the equations and makes a universe for them to describe…. Why does the universe go to all the bother of existing? 

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. 

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. 

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. 

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

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. 

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. 

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

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

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

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! 

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. 

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. 

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

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. 

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. 

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. 

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. 

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. 

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. 

Mankind’s greatest achievements have come about by talking and its greatest failures by not talking. It does’ have to be like this. 

There is no prescribed route to follow to arrive at a new idea. You have to make the intuitive leap. But the difference is that once you’ve made that intuitive leap you have to justify it by filling in the intermediate steps. 

I have hardly ever known a mathematician who was able to reason. 

If we find the answer [the unified theory], it would be the ultimate triumph of human reason – for we would know the mind of God. 

It matters if you just don’t give up. 

In fact, if one considers the possible constants and laws that could have emerged, the odds against a universe that produced life like ours are immense. 

[In the Universe it may be that] Primitive life is very common and intelligent life is fairly rare. Some would say it has yet to occur on Earth. 

Everything that civilisation has to offer is a product of human intelligence; we cannot predict what we might achieve when this intelligence is magnified by the tools that AI may provide, but the eradication of war, disease, and poverty would be high on anyone’s list. Success in creating AI would be the biggest event in human history. Unfortunately, it might also be the last. 

[Asked what he thinks about most during the day] Women. They are a complete mystery. 

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. 

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

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

Not to take this web of dualities as a sign we are on the right track would be a bit like believing that God put fossils into the rocks in order to mislead Darwin about the evolution of life. 

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. 

thus, in a sense, we are all doomed. even if we stay away from black holes 

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. 

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

Intelligence is the ability to adapt to change. 

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. 

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

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. 

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. 

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

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. 

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. 

Life would be tragic if it weren’t funny. 

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. 

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? 

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

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

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. 

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. 

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. 

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. 

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. 

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

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. 

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 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. 

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

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. 

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

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

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. 

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

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

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

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

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. 

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. 

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. 

Theology is unnecessary. 

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? 

Women. They are a complete mystery. 

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

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. 

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. 

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

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

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

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

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

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. 

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

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. 

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

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

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. 

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. 

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. 

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

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

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

I believe things cannot make themselves impossible. 

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

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. 

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

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

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? 

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. 

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

Exploration by real people inspires us. 

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

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. 

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

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

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. 

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

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

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. 

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. 

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

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. 

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

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. 

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. 

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

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. 

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. 

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

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

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

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

What was God doing before the divine creation? 

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

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

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

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

Earth might one day soon resemble the planet Venus. 

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 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. 

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

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

My work and my family are very important to me. 

I enjoy all forms of music – pop, classical and opera. 

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

One cannot really argue with a mathematical theorem. 

There is no unique picture of reality. 

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

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

Computers double their performance every month. 

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

I think the discovery of supersymmetric partners for the known particles would revolutionize our understanding of the universe. 

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

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. 

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. 

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. 

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

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. 

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

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

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

No one can resist the idea of a crippled genius. 

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

We live in a bewildering world. 

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

I had not expected ‘A Brief History of Time’ to be a best seller. 

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

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

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

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. 

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. 

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. 

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

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

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

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

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

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. 

I want my books sold on airport bookstalls. 

There is nothing bigger or older than the universe. 

All my adult life people have been helping me. 

Many people find the universe confusing – it’s not. 

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

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

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

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

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

I have wondered about time all my life. 

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

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

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

Perhaps one day I will go into space. 

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

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

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

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. 

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. 

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. 

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. 

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 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. 

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. 

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. 

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. 

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. 

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. 

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. 

We should seek the greatest value of our action. 

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

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. 

You can’t regulate every lab in the world. 

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

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

It is extremely important to me to write for children. 

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

Cosmology is a rapidly advancing field. 

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

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. 

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

I believe there are no questions that science can’t answer about a physical universe. 

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

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

My wife and I love each other very much. 

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

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. 

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. 

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. 

Among physicists, I’m respected I hope. 

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. 

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

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. 

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. 

The Universe in a Nutshell 

Government works best under the glare of public scrutiny. Absent such scrutiny, abuses occur. 

God abhors a naked singularity. 

Time and space are finite in extent, but they don’t have any boundary or edge. They would be like the surface of the earth, but with two more dimensions. 

We got through all of Genesis and part of Exodus before I left. One of the main things I was taught from this was not to begin a sentence with And. I pointed out that most sentences in the Bible began with And, but I was told that English had changed since the time of King James. In that case, I argued, why make us read the Bible? But it was in vain. Robert Graves was very keen on the symbolism and mysticism in the Bible at that time. 

You cannot understand the glories of the universe without believing there is some Supreme Power behind it. 

One is always a long way from solving a problem until one actually has the answer. 

Science makes god unnecessary. 

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

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. 

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

My three children have brought me great joy. 

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 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. 

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. 

I have sold more books on physics than Madonna has on sex. 

More often than politicians, but not as often as they should. 

Maybe my viriety is due to bad absorption of vitamins. 

there is no prescribed route to follow to arrive at a new idea. You have to make the intuitive leap. But the difference is that once you’ve made the intuitive leap you have to justify it by filling in the intermediate steps. N my case, it often happens that I have an idea, but then I try to fill in the intermediate steps and find that they don’t work, so I have to give it up. 

Nuclear weapons need large facilities, but genetic engineering can be done in a small lab. You can’t regulate every lab in the world. The danger is that either by accident or design, we create a virus that destroys us. 

Whether you want to uncover the secrets of the universe, or you just want to pursue a career in the 21st century, basic computer programming is an essential skill to learn 

Science fiction can be exciting and very gripping, but it doesn’t tell us anything about the universe in which we live. 

Working with my father [Stephen Hawking ] is a great thrill – he has the amazing ability to hold enormous amounts of information in his head. 

When I was young, Stephen Hawking wasn’t the world’s most famous physicist. The fame didn’t arrive until the publication of “A Brief History of Time,” by which time I was in my late teens. When I was a child, he was well known among physicists, but they are a fairly select, serious bunch, not much given to celebrity idolizing. 

One big contribution my father [Stephen Hawking] has made is to show that having a disability does not bar you from leading a full and eventful life. 

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. 

It is very important for young people keep their sense of wonder and keep asking why. 

I’m a child myself, in the sense that I’m still looking. Children are fascinated by black holes and ask me questions. I find they soon get the idea if it is explained in nontechnical language. 

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. It was a natural next step to want to know how the universe works. 

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. 

I want to encourage public interest in space. I have never let my condition stop me. You only live once. 

The lesson of the book is that the universe is governed by the laws of science. 

Being confined to a wheelchair doesn’t bother me as my mind is free to roam the universe, but it felt wonderful to be weightless. 

The idea that we are alone in the universe seems to me completely implausible and arrogant, considering the number of planets and stars that we know exist, it’s extremely unlikely that we are the only form of evolved life. 

Nothing cannot exist forever. 

Without imperfection, you or I would not exist. 

The universe doesn’t allow perfection.