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Stephen Hawking

92 quotes

“It has certainly been true in the past that what we call intelligence and scientific discovery have conveyed a survival advantage. It is not so clear that this is still the case: our scientific discoveries may well destroy us all, and even if they don’t, a complete unified theory may not make much difference to our chances of survival. However, provided the universe has evolved in a regular way, we might expect that the reasoning abilities that natural selection has given us would be valid also in our search for a complete unified theory, and so would not lead us to the wrong conclusions.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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 very finely adjusted to make possible the development of life.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“Galileo, perhaps more than any other single person, was responsible for the birth of modern science.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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!”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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?”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“Science could predict that the universe must have had a beginning.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“We hold these truths to be self-evident that all P-brains are created equal.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.”
Stephen Hawking (1942–2018) first seen 2010 wikiquote, CC BY-SA 4.0 source
Recorded in: Also quoted in "Stephen Hawking warns over making contact with aliens" at BBC News (25 April 2010).
“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.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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.)”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“We are all different — but we share the same human spirit. Perhaps it's human nature that we adapt — and survive.”
Stephen Hawking (1942–2018) first seen 2013 wikiquote, CC BY-SA 4.0 source
Recorded in: Official Trailer<!-- DEAD LINK ** {{cite web |last=Hawking |first=Stephen |title=Hawking (2013) - Official Trailer (02:12) |url=
“If you like, you can call the laws of science 'God', but it wouldn't be a personal God that you would meet and put questions to. Although, if there were such a God, I would like to ask however did he think of anything as complicated as M-theory in eleven dimensions.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“It is a matter of common experience that things get more disordered and chaotic with time. This observation even has its own law, the so-called second law of thermodynamics.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“I discount suggestions that UFOs contain beings from outer space, as I think that any visits by aliens would be much more obvious - and probably also much more unpleasant.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“It is not even clear that intelligence has any long-term survival value.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“[Planck] said instead [of possibility that amount of radiation could have just any value] that radiation came only in packets or quanta of a certain size. It is a bit like saying that you can't buy sugar loose in the supermarket, it has to be in kilogram bags.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“If one made a research grant application to work on time travel it would be dismissed immediately. No government agency could afford to be seen to be spending public money on anything as way out as time travel. Instead one has to use technical terms like closed time-like curves, which are code for time travel.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“I regard it as almost inevitable that either a nuclear confrontation or environmental catastrophe will cripple the Earth at some point in the next 1,000 years which, as geological time goes, is the mere blink of an eye. By then I hope and believe that our ingenious race will have found a way to slip the surly bonds of Earth and will therefore survive the disaster.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“With current technology interstellar travel is utterly impractical. Alpha Centauri can never become a holiday destination.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“It's tempting to dismiss the notion of highly intelligent machines as mere science fiction, but this would be a mistake, and potentially our worst mistake ever.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“If a superior alien civilisation sent us a text 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 has happened with AI.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“If you are disabled, it is probably not your fault, but it is no good blaming the world or expecting it to take pity on you. One has to have a positive attitude and must make the best of the situation that one finds oneself in; if one is physically disabled, one cannot afford to be psychologically disabled as well. In my opinion, one should concentrate on activities in which one's physical disability will not present a serious handicap. I am afraid that Olympic Games for the disabled do not appeal to me, but it is easy for me to say that because I never liked athletics anyway. On the other hand, science is a very good area for disabled people because it goes on mainly in the mind. Of course, most kinds of experimental work are probably ruled out for most such people, but theoretical work is almost ideal. My disabilities have not been a significant handicap in my field, which is theoretical physics. Indeed, they have helped me in a way by shielding me from lecturing and administrative work that I would otherwise have been involved in. I have managed, however, only because of the large amount of help I have received from my wife, children, colleagues and students. I find that people in general are very ready to help, but you should encourage them to feel that their efforts to aid you are worthwhile by doing as well as you possibly can.”
Stephen Hawking (1942–2018) first seen 1984 wikiquote, CC BY-SA 4.0 source
Recorded in: Handicapped People and Science" by Stephen Hawking, Science Digest 92, No. 9 (September 1984): 92 (details of citation from here).
“Einstein is the only figure in the physical sciences with a stature that can be compared with Newton. Newton is reported to have said "If I have seen further than other men, it is because I stood on the shoulders of giants." This remark is even more true of Einstein who stood on the shoulders of Newton. Both Newton and Einstein put forward a theory of mechanics and a theory of gravity but Einstein was able to base General Relativity on the mathematical theory of curved spaces that had been constructed by Riemann while Newton had to develop his own mathematical machinery. It is therefore appropriate to acclaim Newton as the greatest figure in mathematical physics and the Principia is his greatest achievement.”
Stephen Hawking (1942–2018) first seen 1987 wikiquote, CC BY-SA 4.0 source
Recorded in: Newton's Principia" in 300 Years of Gravitation. (1987) by S. W. Hawking and W. Israel, p. 4 Cambridge University Press, Cambridge
“These lectures have shown very clearly the difference between Roger and me. He's a Platonist and I'm a positivist. He's worried that Schrödinger's cat is in a quantum state, where it is half alive and half dead. He feels that can't correspond to reality. But that doesn't bother me. I don't demand that a theory correspond to reality because I don't know what it is. Reality is not a quality you can test with litmus paper. All I'm concerned with is that the theory should predict the results of measurements. Quantum theory does this very successfully. It predicts that the result of an observation is either that the cat is alive or that it is dead. It is like you can't be slightly pregnant: you either are or you aren't.”
Stephen Hawking (1942–2018) first seen 1994 wikiquote, CC BY-SA 4.0 source
Recorded in: During a debate with Roger Penrose in 1994 at the Isaac Newton Institute for Mathematical Sciences at the University of Cambridge, transcribed in The Nature of Space and Time (1996) by Stephen Hawking and Roger Penrose,…
“I'm sorry to disappoint science fiction fans, but if information is preserved, there is no possibility of using black holes to travel to other universes. If you jump into a black hole, your mass energy will be returned to our universe but in a mangled form which contains the information about what you were like but in a state where it can not be easily recognized. It is like burning an encyclopedia. Information is not lost, if one keeps the smoke and the ashes. But it is difficult to read. In practice, it would be too difficult to re-build a macroscopic object like an encyclopedia that fell inside a black hole from information in the radiation, but the information preserving result is important for microscopic processes involving virtual black holes.”
Stephen Hawking (1942–2018) first seen 2005 wikiquote, CC BY-SA 4.0 source
Recorded in: Information Loss in Black Holes" (July 2005)
“The danger is that global warming may become self-sustaining, if it has not done so already. The melting of the Arctic and Antarctic ice caps reduces the fraction of solar energy reflected back into space, and so increases the temperature further. Climate change may kill off the Amazon and other rain forests, and so eliminate once one of the main ways in which carbon dioxide is removed from the atmosphere. The rise in sea temperature may trigger the release of large quantities of carbon dioxide, trapped as hydrides on the ocean floor. Both these phenomena would increase the greenhouse effect, and so global warming further. We have to reverse global warming urgently, if we still can.”
Stephen Hawking (1942–2018) first seen 2006 wikiquote, CC BY-SA 4.0 source
Recorded in: ABC News interview (16 August 2006)
“As scientists, we understand the dangers of nuclear weapons and their devastating effects, and we are learning how human activities and technologies are affecting climate systems in ways that may forever change life on Earth. As citizens of the world, we have a duty to alert the public to the unnecessary risks that we live with every day, and to the perils we foresee if governments and societies do not take action now to render nuclear weapons obsolete and to prevent further climate change... There’s a realization that we are changing our climate for the worse. That would have catastrophic effects. Although the threat is not as dire as that of nuclear weapons right now, in the long term we are looking at a serious threat.”
Stephen Hawking (1942–2018) first seen 2007 wikiquote, CC BY-SA 4.0 source
Recorded in: At a press conference for the Bulletin of the Atomic Scientists, as the Doomsday Clock is moved forward by two minutes to five minutes to midnight, as quoted in "Nukes, climate push 'Doomsday Clock' forward" MSNBC (1 Ja…
“I believe that disabled people should concentrate on things that their handicap doesn’t prevent them from doing and not regret those they can’t do … I visited the Soviet Union seven times. The first time I went with a student party in which one member, a Baptist, wished to distribute Russian-language Bibles and asked us to smuggle them in. We managed this undetected, but by the time we were on our way out the authorities had discovered what we had done and detained us for a while. However, to charge us with smuggling Bibles would have caused an international incident and unfavorable publicity, so they let us go after a few hours.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“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. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“As I shall describe, the prospects for finding such a theory seem to be much better now because we know so much more about the universe. But we must beware of overconfidence - we have had false dawns before! At the beginning of this century, for example, it was thought that everything could be explained in terms of the properties of continuous matter, such as elasticity and heat conduction. The discovery of atomic structure and the uncertainty principle put an emphatic end to that. Then again, in 1928, physicist and Nobel Prize winner Max Born told a group of visitors to Gottingen University, "Physics, as we know it, will be over in six months." His confidence was based on the recent discovery by Dirac of the equation that governed the electron. It was thought that a similar equation would govern the proton, which was the only other particle known at the time, and that would be the end of theoretical physics. However, the discovery of the neutron and of nuclear forces knocked that one on the head too. Having said this, I still believe there are grounds for cautious optimism that we may now be near the end of the search for the ultimate laws of nature.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source
“The ultimate objective test of free will would seem to be: Can one predict the behavior of the organism? If one can, then it clearly doesn't have free will but is predetermined. On the other hand, if one cannot predict the behavior, one could take that as an operational definition that the organism has free will … The real reason why we cannot predict human behavior is that it is just too difficult. We already know the basic physical laws that govern the activity of the brain, and they are comparatively simple. But it is just too hard to solve the equations when there are more than a few particles involved … So although we know the fundamental equations that govern the brain, we are quite unable to use them to predict human behavior. This situation arises in science whenever we deal with the macroscopic system, because the number of particles is always too large for there to be any chance of solving the fundamental equations. What we do instead is use effective theories. These are approximations in which the very large number of particles are replaced by a few quantities. An example is fluid mechanics … I want to suggest that the concept of free will and moral responsibility for our actions are really an effective theory in the sense of fluid mechanics. It may be that everything we do is determined by some grand unified theory. If that theory has determined that we shall die by hanging, then we shall not drown. But you would have to be awfully sure that you were destined for the gallows to put to sea in a small boat during a storm. I have noticed that even people who claim everything is predetermined and that we can do nothing to change it, look before they cross the road. … One cannot base one's conduct on the idea that everything is determined, because one does not know what has been determined. Instead, one has to adopt the effective theory that one has free will and that one is responsible for one's actions. This theory is not very good at predicting human behavior, but we adopt it because there is no chance of solving the equations arising from the fundamental laws. There is also a Darwinian reason that we believe in free will: A society in which the individual feels responsible for his or her actions is more likely to work together and survive to spread its values.”
Stephen Hawking (1942–2018) said by 2018 at the latest wikiquote, CC BY-SA 4.0 source