University Of Cambridge Faculty

"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."

"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."

"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."

"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, E = mc^2. I hope that this will not scare off half of my potential readers."

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

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

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

"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."

"Women. They are a complete mystery."

"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."

"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."

"We should seek the greatest value of our action."

"The Dreams that Stuff is Made of"

"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."

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

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

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

"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!"

"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."

"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."

"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."

"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."

"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."

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

"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."

"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."

"Many people would claim that the boundary conditions are not part of physics but belong to metaphysics or religion. They would claim that nature had complete freedom to start the universe off any way it wanted. That may be so, but it could also have made it evolve in a completely arbitrary and random manner. Yet all the evidence is that it evolves in a regular way according to certain laws. It would therefore seem reasonable to suppose that there are also laws governing the boundary conditions."

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

"The subject of this book is the structure of space-time on length-scales from 10-13cm, the radius of an elementary particle, up to 1028cm, the radius of the universe. ...we base our treatment on Einstein's General Theory of Relativity. This theory leads to two remarkable predictions about the universe: first, that the final fate of massive stars is to collapse behind an event horizon to form a 'black hole' which will contain a singularity; and secondly, that there is a singularity in our past which constitutes, in some sense, a beginning to the universe."

"The fate which Housman's poems deserve, of course, is to be set to music by English composers and sung by English singers, and it has already overtaken them. He will live as long as the B.B.C. does."

"Is this the spectacle of a great mind crippled? Certainly it is the spectacle of a mind of remarkable penetration and vigour, of uncommon sensibility and intensity, condemning itself to duties which prevent it from rising to its full height. Perhaps it is the case of a man of genius who has never been allowed to come to growth. Housman's anger is tragic like Swift's. He is perhaps more pitiable than Swift, because he has been compelled to suppress himself more completely. Even when Swift had been exiled to Ireland, he was able to take out his fury in crusading against the English. But A. E. Housman, giving up Greek in order to specialize in Latin because he "could not attain to excellence in both," giving up Propertius, who wrote about love, for Manilius, who did not even deal with human beings, turning away from the lives of the Romans to rivet his attention to the difficulties of their texts, can only flatten out small German professors with weapons which would have found fit employment in the hands of a great reformer or a great satirist. He is the hero of The Grammarian's Funeral—the man of learning who makes himself impressive through the magnitude, not the importance, of his achievement. After all, there was no need for another Bentley."

"The Shropshire of Housman's imagination is at once curiously realistic and romantic—a land of faerie yet of solid earth, somewhat like that depicted on the shield of Achilles in the Iliad. A beautiful world is set as a magic stage for the course of human wilfulness, perversity, and tragic fate. A strong vein of what many would call pessimism runs through the whole: these "lads," these soldiers and other companions of the poet, are pitted against destiny on an earthly stage of ironical enchantment under the cope of mathematically ordered cosmic processes."

"As the creator of "A Shropshire Lad" he was well known and admired wherever English poetry is read; while among classical scholars the Professor of Latin at Cambridge had earned for himself a place among the greatest editors and critics in the long history of classical scholarship. Surprising as it may seem to those of his readers who know only his poetry, his attainments in scholarship were higher than they were in poetry."

"No one when he reads...the pieces which begin "There pass the careless people" and "If truth in hearts that perish" can doubt that they were inspired by actual experience of the passion of love. But Housman did not often express these feelings directly in his published poems. A clerk in the Patent Office, even a Professor in Cambridge, could not confess to affections of which a poet could speak only in ancient Greece. Like Gray, therefore, and for the same reason, Housman "never spoke out". For the most part, he held his peace – "Ask me no more, for fear I might reply"."

"His saeva indignatio was nearly always reserved for pretentious incompetence, intellectual fraud, meanness of spirit, and that compound of the three which makes men band together, with cries of mutual encouragement, round a fashionable totem. Against these things Housman waged war, without respect of persons or enmity towards them."

"Housman was a marvel of learning and brilliancy and penetration: and he had, or came to have, the prime virtue; which is to say that he clung to reality, abhorring from the bottom of his soul all efforts to fit it upon frames or smother it in cotton wool. Reality, in philology as elsewhere, is often inconvenient. So much the worse: "They say my verse is sad"."

"When I ask myself what it is that has made my readings of the Manilius the most memorable intellectual experience of my life, I look to another quality, which I find in no other comparable scholar to anything like the same degree. I mean Housman's unremitting, passionate zeal to see each one of the innumerable problems in his text not as others had presented it or as he might have preferred it to appear but exactly as it was."

"As a classical scholar Housman was, beyond serious dispute, among the greatest of all time. Not the greatest, certainly: of Bentley's superiority in their common field of textual criticism he was himself intolerantly convinced. And he would never have denied that Mommsen and Wilamowitz were cast in a larger mould. He published much; but the measure of his scholarship, as of his verse, was narrow. Apart from some early work on Greek tragedy, he devoted himself almost exclusively to the text and interpretation (I use the latter word in its restricted sense) of classical Latin poets. He says of his commentary on the astrologer poet Manilius, his magnum opus, that it is designed to treat of two matters only: what Manilius wrote and what he meant. And almost everything that Housman published on classical authors—the editions of Juvenal and Lucan, as well as the mass of articles in learned journals—might be similarly described."

"May I lay stress on the nobility and humanity of Housman's character? I have known many poets great and small...but I have known no poet and no scholar—and, indeed, no man—who impressed me as so great and human a being as Housman did... He was great and yet he was not chill; he was noble and yet he could unbend. I, who have travelled with him for weeks together, saw, and felt, now and again, an impatience with fools, and yet there went always with it some understanding of, and sympathy with, folly. He was always tolerant, greatly tolerant. He could understand the weaknesses of others. A great man, yes."

"One morning in May, 1914, when the trees in Cambridge were covered with blossom, he reached in his lecture Ode 7 in Horace's Fourth book, "Diffugere nives, redeunt iam gramina campis." This ode he dissected with the usual display of brilliance, wit, and sarcasm. Then for the first time in two years he looked up at us, and in quite a different voice said: "I should like to spend the last few minutes considering this ode simply as poetry." Our previous experience of Professor Housman would have made us sure that he would regard such a proceeding as beneath contempt. He read the ode aloud with deep emotion, first in Latin and then in an English translation of his own. "That," he said hurriedly, almost like a man betraying a secret, "I regard as the most beautiful poem in ancient literature," and walked quickly out of the room. A scholar of Trinity (since killed in the War), who walked with me to our next lecture, expressed in undergraduate style our feeling that we had seen something not really meant for us. "I felt quite uncomfortable," he said. "I was afraid the old fellow was going to cry.""

"The exhilaration was produced by watching what seemed to be a mental machine of great power and precision applied to material at first sight unexpected... The severity of Housman's presentation was the severity not of passionlessness but of suppressed passion, passion for true poetry and passion for truthfulness. For Housman textual criticism was the exercise of moral self-discipline... The phrases remembered over the years flashed from the inner furnace of passion for truth and logical thought, and of indignation against every interest or influence which could corrupt it... Under the radiation of this display of a great critical mind in action, one's own powers, such as they might be, developed – above all, the spirit of bold but temperate self-reliance without which no criticism is possible."

"Again as with a bullfight, you never appreciate this sport till you see a really great performer. Something departed for ever from the pleasure of specialist review reading when A. E. Housman gibbeted his last victim."

"Housman is a "country" poet. His poems are full of the charm of buried villages, the nostalgia of place-names, Clunton and Clunbury, Knighton, Ludlow, "on Wenlock Edge", "in summer time on Bredon", thatched roofs and the jingle of smithies, the wild jonquils in the pastures, the "blue, remembered hills"."

"At the beginning of the period I am speaking of, the years during and immediately after the war, the writer who had the deepest hold upon the thinking young was almost certainly Housman. Among people who were adolescent in the years 1910–25, Housman had an influence which was enormous and is now not at all easy to understand. In 1920, when I was about seventeen, I probably knew the whole of the Shropshire Lad by heart... these are the poems that I and my contemporaries used to recite to ourselves, over and over, in a kind of ecstasy."

"A. E. Housman I can always read, in spite of his detestable philosophy."

"He published about 235 articles and edited Lucan, Juvenal, and five volumes of Manilius between 1903 and 1930. Widely acknowledged as the greatest scholar of his age, he could justly claim with Horace: Exegi monumentum aere perennius (I have built a monument more lasting than bronze)."

"When passing through Berlin in the summer of 1926 I had the privilege of spending an interesting afternoon with the late Professor Ulrich von Wilamowitz-Moellendorff at his house in Charlottenburg. I remember that we were discussing the various ways of pronouncing Homer, when he suddenly remarked, "Although we Germans know Housman to be a rabid Germanophobe, we, nevertheless, unanimously pronounce him to be the greatest living authority on both Latin and Greek in the English-speaking world. His latest work is above praise." Professor Wilamowitz-Moellendorff was not aware until afterwards that he was addressing these words to an old pupil, and also an old friend, of Professor Housman."

"In his last year at Oxford Housman shared lodgings with two friends, A. W. Pollard and Moses Jackson. Jackson was a brilliant scientist, certain of a First, tall, well-built, handsome and self-confident. Housman, short, shy and undistinguished in appearance, worshiped him. Too clear-headed and honest to deceive himself about the nature of this absorption, he was also too well trained in conventional morality to accept it with resignation. The evidence of his poetry suggests that he was overwhelmed with shame. His Christian faith had gone at the age of thirteen, when he became a deist; by twenty-one he was an atheist. At heart he defied the world; but outwardly, circumstances and a naturally conformist temper of mind preserved an appearance of rigid propriety. He hid his emotions and for the rest of his life felt the bitterness of the frustration."

"In later years Housman liked to attribute the "morbid secretion" of poetry to illness, but it seems to have been a state of guilt that brought his poems into existence. His father's death revived long-suppressed conflicts between parental duty and the annihilating force of his "nameless and abominable" love. A catalyst in this process...may well have been the Oscar Wilde trial, which must have demonstrated to Housman's painfully conformist mind just how ruthlessly "the laws of God, the laws of man" were interpreted and enforced in Victorian England."