From: Richard Dawkins
"By Darwinian evolution he [Carl Woese] means evolution as Darwin understood it, based on the competition for survival of noninterbreeding species."
"With rare exceptions, Darwinian evolution requires established species to become extinct so that new species can replace them."
These two quotations from Dyson constitute a classic schoolboy howler, a catastrophic misunderstanding of Darwinian evolution. Darwinian evolution, both as Darwin understood it, and as we understand it today in rather different language, is NOT based on the competition for survival of species. It is based on competition for survival WITHIN species. Darwin would have said competition between individuals within every species. I would say competition between genes within gene pools. The difference between those two ways of putting it is small compared with Dyson's howler (shared by most laymen: it is the howler that I wrote The Selfish Gene partly to dispel, and I thought I had pretty much succeeded, but Dyson obviously hasn't read it!) that natural selection is about the differential survival or extinction of species.
Of course the extinction of species is extremely important in the history of life, and there may very well be non-random aspects of it (some species are more likely to go extinct than others) but, although this may in some superficial sense resemble Darwinian selection, it is NOT the selection process that has driven evolution.
Moreover, arms races between species constitute an important part of the competitive climate that drives Darwinian evolution. But in, for example, the arms race between predators and prey, or parasites and hosts, the competition that drives evolution is all going on within species. Individual foxes don't compete with rabbits, they compete with other individual foxes within their own species to be the ones that catch the rabbits (I would prefer to rephrase it as competition between genes within the fox gene pool).
The rest of Dyson's piece is interesting, as you'd expect, and there really is an interesting sense in which there is an interlude between two periods of horizontal transfer (and we mustn't forget that bacteria still practice horizontal transfer and have done throughout the time when eucaryotes have been in the 'Interlude'). But the interlude in the middle is not the Darwinian Interlude, it is the Meiosis / Sex / Gene-Pool / Species Interlude.
Darwinian selection between genes still goes on during eras of horizontal transfer, just as it does during the Interlude. What happened during the 3-billion-year Interlude is that genes were confined to gene pools and limited to competing with other genes within the same species. Previously (and still in bacteria) they were free to compete with other genes more widely (there was no such thing as a species outside the 'Interlude'). If a new period of horizontal transfer is indeed now dawning through technology, genes may become free to compete with other genes more widely yet again.
As I said, there are fascinating ideas in Freeman Dyson's piece. But it is a huge pity it is marred by such an elementary mistake at the heart of it.
From: Freeman Dyson
Dear Richard Dawkins,
Thank you for the E-mail that you sent to John Brockman, saying that I had made a "school-boy howler" when I said that Darwinian evolution was a competition between species rather than between individuals. You also said I obviously had not read The Selfish Gene. In fact, I did read your book and disagreed with it for the following reasons.
Here are two replies to your E-mail. The first was a verbal response made immediately when Brockman read your E-mail aloud at a meeting of biologists at his farm. The second was written the following day after thinking more carefully about the question.
First response. What I wrote is not a howler and Dawkins is wrong. Species once established evolve very little, and the big steps in evolution mostly occur at speciation events when new species appear with new adaptations. The reason for this is that the rate of evolution of a population is roughly proportional to the inverse square root of the population size. So big steps are most likely when populations are small, giving rise to the "punctuated equilibrium'' that is seen in the fossil record. The competition is between the new species with a small population adapting fast to new conditions and the old species with a big population adapting slowly.
Second response. It is absurd to think that group selection is less important than individual selection. Consider for example Dodo A and Dodo B, competing for mates and progeny in the dodo population on Mauritius. Dodo A competes much better and has greater fitness, as measured by individual selection. Dodo A mates more often and has many more grandchildren than Dodo B. A hundred years later, the species is extinct, and the fitness of A and B are both reduced to zero. Selection operating at the species level trumps selection at the individual level. Selection at the species level wiped out both A and B because the species neglected to maintain the ability to fly, which was essential to survival when human predators appeared on the island. This situation is not peculiar to dodos. It arises throughout the course of evolution, whenever environmental changes cause species to become extinct.
In my opinion, both these responses are valid, but the second one goes more directly to the issue that divides us.
Yours sincerely,
Freeman Dyson
JB
Editor, Edge
ESTHER DYSON
Investor; Chairman, EDventure Holdings; Executive Founder, Wellville; Author: Release 2.0
Memories of My Father
It always seems a bit odd to be proud of one’s parents; one can be proud of one’s children (whom one helped to form), but I was just lucky to have Freeman as a father. And he was indeed a wonderful father. For starters, he worked near our house (at the Institute for Advanced Study) and walked back and forth to work. On snowy days, he would ride my brother George’s and my sled instead, and we would have to run down to his office and pick it up if we wanted to go sledding after school. That was always fun; he had a blackboard with interesting equations all over it.
He and my stepmother Imme were also ideal parents in giving us lots of freedom tempered with responsibility. I remember wanting to run away in my mid-teens because it seemed like the cool thing to do, but there were really no rules I could protest against. My parents were so reasonable!
Later on, when I was 17 and took some time off college to go live in Morocco with my boyfriend (who was in the Peace Corps), they said (paraphrase): "Go ahead! If you are put in jail [presumably for drugs], we won’t get you out. If you get pregnant, we won’t raise the baby. But we love you, and we wish you well!"
Later on, I did things even more outré for this family: I became a businessperson, though at least focused on tech and the Internet. Freeman and Imme (and much of the rest of our growing family) came to my annual tech conference each year. Imme sat in the audience knitting while listening attentively; Freeman engaged in conversation with the small number of people who "knew who he was." I have received letters from many of them in the weeks since his death.
Each time I embarked on something new, they wished me the best with love and tolerance. But then something new happened.
I got interested in space travel. I had pretty much ignored it growing up. I knew that when Freeman and Imme were kids, air travel had been something new and exciting, but by the time I was growing up it had become routine. My first trip to the US (I was born in Switzerland) was by boat, but when we went back to Europe we took airplanes.
So, though I knew Freeman was involved with space travel, I figured he and his friends would make it routine, and perhaps a bit boring. And I certainly knew he could do that without my help!
But as the 2000s proceeded, it became clear that space was not moving ahead as I had expected, and I got interested. I ran a new space conference called Flight School and got him to be the keynote speaker—which delighted me and everyone! And then, a couple of years later, I decided to sign up for cosmonaut training in Russia as a backup to Charles Simonyi, the creator of Microsoft Word and also, as it happens, a trustee of the Institute since 1997 (and now Chairman). I told my parents about it over dinner in a restaurant in New York.
This time, instead of offering his genial wish-you-best-at-whatever-you-want response, Freeman jumped up and hugged me. Suddenly I realized that I, his first-born, was about to embark on training for an experience he had been dreaming about for 80+ years (though it is Charles who actually went to space, twice; I was just a backup). I knew he had always been proud of me (and his five other kids), but that was clearly the moment I gave him the most joy. I treasure it still.
MARTIN REES
Former President, The Royal Society; Emeritus Professor of Cosmology and Astrophysics, University of Cambridge; Fellow, Trinity College; Author, From Here to Infinity
I first met Freeman in 1969, while spending a few months at the Institute for Advanced Study (IAS); I was one of the first postdocs to join John Bahcall, who had recently arrived to build up an astrophysics group.
Princeton was rather daunting to a timid young Brit. But Freeman was, from the start, engaging and friendly. Indeed, he and his wife Imme invited me several times to Sunday breakfasts at his home. These were cheerful occasions—round a big table with his four daughters, the youngest only three. It was Freeman, more than anyone, who convinced me that the IAS was a place I wanted to maintain contact with (I later became a Trustee)—and on every visit the chance to chat with Freeman was a bonus.
He exemplified the value of the IAS—no other institution could have enabled someone with his intellectual range to flourish, and to stimulate so many for so long. His achievements in theoretical physics secured his reputation while he was in his twenties. But he spent the remaining sixty-five years indulging his curiosity and deploying his immense talent across many fields.
During my visits we discussed, for instance, the far future of our universe. I'd written a paper on a "closed universe" that would re-collapse to a big crunch. Freeman didn't like this: he said the concept "gave him claustrophobia." He later (in 1979) wrote a classic (and very long) article on the future of an ever-expanding universe. One of his talents was for clear writing and exposition. He thought that young scientists should write papers and old ones should write books. He was already in his fifties when he published his first book Disturbing the Universe, his books and general writings (especially those in the New York Review of Books) are an important part of his legacy.
I resonated with his attitude that the diversity of the living world should stimulate our sense of wonder as much as the austere beauty of math and physics—and his non-dogmatic engagement of religion. (In the latter context, when I received the Templeton Prize, he told me that this made him feel better about having won it himself, as I'd done just as little to deserve it as he had! (Of course, I'd actually done far less.)
When I first met him, he had already been based for twenty years in the US. He nonetheless retained the aura of an old-style English academic. This wasn't surprising when I learnt more about his origins. His father, a composer, became head of the Royal College of Music. Freeman attended Winchester College, where his father was then teaching. This ancient school was an academic hothouse. But Dyson and a classmate James Lighthill stood out as mathematically precocious even in a class where several scientists achieved eminence. They went on to Trinity College, Cambridge; both became FRSs before they were thirty.
Lighthill had a wide-ranging career: for ten years he was Lucasian Professor in Cambridge, between the tenures of Dirac and Hawking. He died at seventy-four. His hobby was long-distance swimming, especially around islands; he several times swam round Sark—nine miles. But, on his last attempt, his heart gave out just before the end.
Freeman survived to be ninety-six—fully active mentally right to the last week of his life—engaging in email correspondence with friends around the world, and hosting guests in the IAS's cafeteria—indeed he died three days after falling there, while carrying his lunch-tray. A unique intellect—and a great and kind man.
DAVID KAISER
Germeshausen Professor of the History of Science, Program in Science, Technology, and Society; Professor of Physics, MIT; Author, Quantum Legacies: Dispatches from an Uncertain World
Freeman Dyson, Scribbler
I first met Freeman Dyson in January 2001. He greeted me at the Institute for Advanced Study (IAS) in Princeton, New Jersey, where he had worked, by then, for nearly a half century. Though he was in his late seventies, Dyson was elfish and spry, bounding upstairs two at a time.
I was there to interview him for a book I was writing, about how physicists had learned to calculate subtle effects among elementary particles using a theory known as "quantum electrodynamics," or QED. Dyson had played a pivotal role in those developments during the late nineteen-forties, consolidating and pushing forward the insights of three other physicists—Richard Feynman, Julian Schwinger, and Sin-Itiro Tomonaga. These three later shared the Nobel Prize for the work, but it was Dyson’s contribution that made QED a workable theory. Building directly on Dyson’s work, physicists have been able to make theoretical predictions about the behavior of particles like electrons with unprecedented accuracy. When compared with the results of ultra-sensitive experiments, their answers agree to one part in a trillion. That’s like estimating the distance from a bench in Central Park and a particular crater on the Moon and getting the answer right within the width of a human hair.
That January afternoon, Dyson graciously sat with me for a two-hour interview, fielding my questions about the origins of QED—how the theory had evolved in collaboration with students and colleagues. As we were wrapping up, I sheepishly asked about something more personal. I’d recently seen some of Dyson’s correspondence quoted in a colleague’s book: letters he had written to his parents and his sister during some of the most exciting periods of his work. Could I see them?
The moment I spoke the question aloud, I was overcome by awkwardness. It felt like asking to read his childhood diary. But, without hesitating, Dyson hopped out of his chair, pulled open some file cabinets, and produced several thick folders, bulging with letters. Even more remarkably, he set me up with a photocopy machine and a spare key to his office, so I could make copies of the entire collection.
The letters chart his arrival in the United States, beginning in September 1947, when he came to Cornell University as a graduate student to study theoretical physics. He wrote home often, some weeks more than once. Sometimes he wrote out the letters by hand, but most often he used an inexpensive, portable typewriter. The originals give an impression of his quick mind at work; often stray letters appear above or below a given line, the typewriter’s strained mechanisms no match for the speed of Dyson’s thinking.
Rather than dwell on his studies, Dyson began to play amateur anthropologist, since his family (back in Britain) had never visited the United States. Roaming beyond Ithaca, Dyson hitch-hiked to New York City with friends and took long bus rides up and down the East coast and into the Midwest. He sent thoughtful observations of race relations in Chicago, St. Louis, and Ypsilanti, Michigan, and described the "endless succession of rich well-tended farms and rich ill-tended industrial cities" on a long ride from Chicago back East.
His letters also record his deepening friendship—and budding collaboration—with Feynman, who was then a young physics professor at Cornell. The famously charismatic physicist struck Dyson as "half genius and half buffoon, who keeps all physicists and their children amused with his effervescent vitality." Feynman was still working out his new diagram-based approach to QED, but had not yet written any detailed account of his thinking; his descriptions of how to use the diagrams struck Dyson as scattered and imprecise.
Dyson enjoyed an epic, cross-country drive with Feynman in June 1948, and took in a series of lectures by Schwinger at the University of Michigan that summer. He explained to his parents that during the long bus ride back East, he fell into "a sort of semistupor," letting Schwinger and Feynman’s competing approaches to QED swirl in his head. "Gradually my thoughts grew more coherent, and before I knew where I was, I had solved the problem that had been in the back of my mind all this year, which was to prove the equivalence of the two theories." It was an epiphany that changed Dyson’s path, and the path of physics as a whole.
I have found myself returning to Dyson’s letters over the years, long after my own research was complete. Most of them are now available in a moving collection that Dyson published in 2018, Maker of Patterns: An Autobiography Through Letters, though often I dig out the old stack of photocopies that I made that day in his office, to feel the immediacy of the nineteen-forties typeface, and the uneven, hurried lines of a mind in motion. Dyson is rightly celebrated as a scientist with a rare skill for distilling complexity and piquing curiosity, who found ways to corral the confusions of a messy world into a tidy order. As a correspondent, he revealed himself as a different sort of thinker—casually wise, surprisingly earnest, and always attuned to the multiple layers of our human existence. His essays introduce us to big ideas; his letters enrich us with details.
(Excerpted with permission from "Freeman Dyson’s Letters Offer Another Glimpse of Genius" by David Kaiser, in The New Yorker, 5 March 2020.)
GEORGE DYSON
Science Historian; Author, Turing’s Cathedral, Darwin Among the Machines
When I was a small child, my father Freeman Dyson sometimes had nightmares and would wake me up to talk. He described being faced with either a burning aircraft or a building engulfed in flames. There were people inside and he was unable to help. These nightmares seemed to be a reflection of his duties, while still a teenager, at RAF Bomber Command during World War II. The flying crews, mostly boys his own age or younger, were being relentlessly lost. As a statistician working in operations research, he was left alone with the knowledge of exactly how poor their chances of survival were, and how many civilians were being incinerated by the bombs that were being dropped.
Freeman’s otherwise incongruous departures from everyday physics and mathematics can be seen as attempts to make amends: the effort to design and launch a fleet of interplanetary space ships, powered by re-purposed weapons, on a peaceful exploration of the solar system; his hypothesis of how life and mind might survive for an apparent eternity even in a dying universe; his recent upending, with Bill Press, of the accepted view of the Prisoner’s Dilemma; his 1976 study for the U.S. Department of Energy of the problem of excess carbon dioxide in the atmosphere, concluding that planting trees is the solution that requires the least sacrifice by the general population, and scales best.
Freeman is known for his insight into quantum electrodynamics at age twenty-four, and an attempt to calculate the number of atoms in the sun at the age of five. The real breakthrough may have come at the age of eight, when he was sent away from home to Twyford School in the UK. "It was an abominable school but had an excellent library so that was my refuge," he explains. "There was lots and lots of stuff about electrons and electricity and radio waves and all sorts of things, but nobody ever mentioned protons and I couldn’t figure out why. I remember asking people, 'Why is it that they only talk about electrons and not about protons?' Nobody seemed to know."
At Twyford, Freeman organized a raffle, taking in small amounts of money from other students, paying half of it back to the winner, and pocketing the rest. "Yes, they knew I was keeping half of it," he admits, "but they kept giving me their money!"
Money well spent.
JENNIFER JACQUET
Assistant Professor of Environmental Studies, NYU; Author, Is Shame Necessary
I heard Freeman Dyson at his Town Hall lecture in Seattle in December 2006—at least five years before CRISPR-Cas9 for genome editing was in the intellectual ether. The thesis of his talk was that the Darwinian era we were all living in—one with temporary coalitions of selfish genes—was likely coming to a close. Dyson explained confidently that we are welcoming back an era of "Woeseian" horizontal gene transfer—the kind that occurred in pre-bacterial times. This horizontal gene transfer would be similar in means to the ancient past, but in the hands of humanity would obviously result in highly modified forms.
What was most striking was how excited and hopeful Dyson seemed about this future, where technology would compensate for what it destroys. It made my reservations over technological advances and admiration for our familiar lifeforms that evolved through evolution by natural selection (thank you very much) feel conventional and limiting. For people like me, happy in the slow lane of evolution, Dyson said there was outer space, where there will again be speciation in the Darwinian sense.
With Freeman’s loss comes not a loss of dreaming—that seems to still exist—but a special kind of thinking while dreaming that makes other people think, too.
MAX TEGMARK
Physicist, MIT; Researcher, Precision Cosmology; Scientific Director, Foundational Questions Institute; President, Future of Life Institute; Author, Life 3.0
I was planning to visit Freeman Dyson again this month, and I'm deeply saddened that we've lost this science titan. I've had the honor and pleasure of knowing him for the past two decades, but when I first met him, I felt nervous. I was a junior postdoc chowing away with my friends in the lunch room of the Institute for Advanced Study in Princeton, and out of the blue, this world-famous physicist who used to hang out with Einstein and Gödel came up and introduced himself, asking if he could join us. He quickly put me at ease, however, by explaining that he preferred eating lunch with young folks over stuffy old professors. No idea was too big or too wild for him, and aside from his seminal mainstream work in figuring out the smallest building blocks of matter, he also invented Dyson spheres that harvest the light of a star and published the first thorough scientific analysis of our far future.
As we humans plan our future, let's consider the meaning not only of our own lives, but also of our Universe itself. Nobel laureate Steven Weinberg famously said, "The more the universe seems comprehensible, the more it also seems pointless." Freeman, on the other hand, was much more optimistic: although he agreed that our Universe was pointless, he argued that life is now filling it with ever more meaning, with the best yet to come if life succeeds in spreading throughout the cosmos. I agree: the best tribute the rest of us can pay to Freeman is to be good stewards of our technology so that we don't go extinct, but help life flourish on Earth and far beyond like he envisioned.
RICH MULLER
Professor of Physics, UC Berkeley (emeritus); Author, Energy for Future Presidents
I recall having lunch with Freeman Dyson, maybe twenty years ago, just him and me, one on one. It had been a flattering experience. The great Freeman Dyson had seemed very interested in me, my thought, what I was doing, my plans!
After lunch, I thought about it. Dyson had been very quiet, except when asking insightful questions. He had been so interested in my answers that I had talked on and on and on. Dyson seemed to have enjoyed the lunch, and he seemed eager to sit down with me at subsequent opportunities. But something bothered me. I realized that although he may have learned a few things from me, I had learned almost nothing from him. I almost felt tricked. In fact, he was just practicing something he had developed over the years: the skill of intense listening.
So, I really did learn something important from him. I had lunch with him again the next week, and I managed to keep my mouth relatively shut, and to concentrate on asking probing questions. I was able to draw him out and learn a lot about his incisive views of physics, math, and the world.
The art of listening, listening deeply enough with concentration and with alertness, active listening that enables you to ask the relevant questions in real time (rather than to think of them afterwards), that kind of listening is a skill that I first observed when Freeman Dyson applied it to me.
Many people mistakenly think that Freeman Dyson’s main skill was mathematical. I learned that day that his ability was far more multidimensional than that.
It is remarkable what you can learn from a great person when he doesn’t say much.
SUSAN SCHNEIDER
Director, AI, Mind and Society Group, The University of Connecticut; Distinguished Scholar, US Library of Congress; Author, Artificial You
Freeman Dyson is of course famous for his intellectual work, but he was much more than a brilliant mind—he was a kind and humble person. I was honored to be one of his lunchtime friends at the Institute. (We met when Freeman was a youthful ninety-three!) Our conversations circled around themes like evolution, interstellar exploration, quantum mechanics, and artificial intelligence, and they made my time at the Institute very exciting. Freeman thought it was amusing that he became a household name for science fiction readers everywhere (as well as astrobiologists) because of his concept of a Dyson Sphere. I don't think he really took the idea all that seriously! He's a bright light, and he will be missed.
GINO SEGRE
Professor of Physics and Astronomy, University of Pennsylvania; Author, The Pope of Physics: Enrico Fermi and the Birth of the Atomic Age
I admired Freeman Dyson tremendously for a number of reasons. First of all, he was a truly great scientist with marvelous achievements that range through so very many areas of physics and mathematics. He was the last person to have known well the earlier generation of physics giants who shaped the modern discipline: Einstein, Bohr, Heisenberg, Pauli, Fermi, Bethe, and of course Feynman. He also knew my wife’s physicist-father from Los Alamos days. I always thought this memory of old days accounted for the extra twinkle he seemed to convey when she and I would run into him.
He was a marvelous writer, an exquisite stylist who tackled an immense variety of subjects in a challenging, thought-provoking manner. Anything Dyson wrote was worth studying; even in old age, I thought he was intellectually the most interesting person I knew. And he was kind.
He wrote a long essay on my book Faust in Copenhagen for the New York Review of Books. Some friends thought I would be upset by a point Dyson made that disagreed with me. But I was not. I understood his reasoning and, I must confess, was pleased to see him devote so much time and thought to the book.
Max Delbruck and George Gamow were the two main protagonists of my next book, Ordinary Geniuses. Freeman and I admired these two maverick scientists. I did not know them personally, but he did and very kindly shared with me his correspondence with them. When the manuscript was finished, he read it and provided me with a blurb that was more than I dared hope for. It ended by saying about Delbruck and Gamow that "This book brings them magnificently to life. It also gives us a fresh view of the way new sciences are born."
Freeman often took pleasure in being controversial and challenging conventional views. Recently this was the case in his statements about drawing conclusions on climate change by mathematical modeling. A smaller but illustrative example of this occurred when we were both on a panel discussion that followed a theater presentation of Brecht’s Galileo. When the topic of destruction in World War II came up Freeman took everybody by surprise saying, "I remember being very young, lying in bed hearing the bombs fall all around me and thinking that this was great for it meant the end of the British Empire, which I of course despised."
FRANK TIPLER
Professor of Mathematical Physics, Tulane University; Coauthor (with John Barrow), The Anthropic Cosmological Principle
Freeman Dyson Against the Heat Death
In 1979, Freeman J. Dyson published a remarkable paper entitled "Time Without End: Physics and Biology in an Open Universe." In this paper, Dyson showed that it might be physically possible for life to continue forever. The Heat Death was not inevitable! I have spent my entire life developing the implications of Dyson’s paper.
For the entire century preceding Dyson’s paper, both physicists and the general public believed that the universe would end in the Heat Death, a state of constant entropy in which life would be physically impossible.
H. G. Wells described it in his Time Machine:
the Sun was dying, so life on Earth was also dying thirty million years from now.
Bertrand Russell described it in A Free Man’s Worship:
… all the labors of the ages, all the devotion, all the inspiration, all the noonday brightness of human genius, are destined to extinction in the vast death of the solar system, and that the whole temple of Man's achievement must inevitably be buried beneath the debris of a universe in ruins …
Dyson challenged this horrible prediction of our ultimate future. He pointed out that in a universe that expands forever but continually slows down, the Heat Death could be avoided, because in such a universe, the temperature goes to zero and life could expand indefinitely into new regions. In my book with John Barrow, The Anthropic Cosmological Principle, I extended Dyson’s work to closed universes. I gave the full details of how life can be immortal in a closed universe in a separate book, The Physics of Immortality. Unfortunately, the year after the latter book appeared, disaster struck Dyson and I: the universe was proven to be accelerating.
Dyson was the first to emphasize that the observed constant acceleration of the universe would eliminate life, because life cannot expand beyond the Virgo cluster if the observed acceleration rate is constant. My closed universe argument would be in even worse shape, because in a closed universe, life can go on forever only if the universe ends in a final singularity.
Once again, Dyson showed how to save the universal biosphere from extinction. Hawking had shown in the 1970s that were black holes to evaporate to completion, the quantum mechanical property of "unitarity" would be violated. Dyson correctly pointed out that since unitarity is implied by energy conservation, it cannot be violated. Combining Dyson’s insight with Hawking’s, it follows that somehow the acceleration must be halted, given that black holes have been observed, and if the universe were to accelerate forever, these observed black holes would necessarily evaporate to completion.
The only question to be answered is how exactly the universal expansion will be halted. I am sure that had Dyson been given only a few more years, he would have solved this problem also. After all, he never stopped making great new discoveries, and the Heat Death was his greatest enemy.
DANNY HILLIS
Physicist, Computer Scientist, Cofounder, Applied Invention; Author, The Pattern on the Stone
I first met Freeman Dyson after giving a presentation at a physics conference. He introduced himself after my talk and made a kind comment about what I had said. I was elated. Then, the person following me gave an incomprehensible presentation. The only positive thing about it was that he carefully enunciated every word. Afterwards, I noticed Freeman complimented him also. "You spoke very clearly," said. To this day, I still wonder what Freeman said to me.
I was far too awed to initiate a conversation with the great Freeman Dyson, but I did sit next to him on the bus. At some point he leaned over and glanced at mathematics paper I was reading. "Are those Q-factorials?" he asked with excitement. It was as if I had opened a box of chocolates. That broke the ice, and our friendship continued for the rest of his life.
There will be many who describe Freeman Dyson’s brilliance, but what I loved most about him was his kindness and childlike enthusiasm. Our conversations were mostly technical, but he always loved to reach for a personal connection. "I wish you would write more often when you have stories to tell," he wrote me in a recent email. It was the kind of the thing he said often, with grace and sincerity. He was deeply kind, not just to his friends and his beloved family, but to complete strangers. He wrote kind replies to the people who sent letters of complaint about their Dyson vacuum cleaners, mistaking him for the inventor.
His impish sense of fun was never far from the surface. I visited him last spring at the Institute for Advanced Study to discuss self-organizing systems. After lunch we climbed up the long stairs to his office on the second floor and he seemed impossibly frail. I was concerned that the climb was too much him, and when we reached his office, he was winded and seemed distracted as he sat down to catch his breath. I asked him what was wrong. "Well," he said, "what seems wrong is that self-gravitating systems have negative specific heat capacity. The thing to do is to figure out why that is right!" He chuckled at his own joke, and we went back to work.
BRIAN KEATING
Chancellor’s Distinguished Professor of Physics, University of California, San Diego; Author, Losing the Nobel Prize: A Story of Cosmology, Ambition, and the Perils of Science's Highest Honor
I met Mr. (not Dr., as he often reminded me!) Freeman Dyson in early 2016 at the beginning of his annual visits to La Jolla to escape New Jersey winters in his later years. It was the beginning of a wonderful friendship, not only with me, but also with my family. Freeman’s visit coincided with the birth of my third child, a daughter named Orli. It tickled me to see the pure joy Freeman (aged 94) had interacting with Orli and her older brothers. We hosted Freeman and his wife Imme for delightful dinners and conversation, and I had the honor of hosting several events with him as well, including the podcast interview that I will always treasure.
In 2017, as my book Losing the Nobel Prize was coming together, I asked Freeman if he’d be willing to write me a "blurb." Naturally, in my request I slathered him with praise, which was not hard to do! I closed by telling him the truth: unlike me, he had actually "lost" a Nobel Prize he truly deserved! Freeman was a master of letters, as his final book, Maker of Patterns: An Autobiography Through Letters, keenly attests. His response was classic Freeman:
Dear Brian,
Congratulations for getting the book done, and my love to Orli. My problem with blurbs is that I have a strict rule not to write blurbs unless I have actually read the book, and I already have a big pile of unread books waiting. The idea is that a blurb is supposed to be an honest expression of information for the reader, not just a favor for the writer. Perhaps a silly old-fashioned idea. Anyhow I hope the book does well without my help.
Yours ever,
Freeman Dyson
Freeman, as always, was the epitome of class and graciousness. While my book arguably did do well, I know it will be challenging for those of us who knew him to continue to thrive without his "help." His loss brings great sorrow, not only for me, but also for all those who have ever wondered so longingly about the meaning of it all. Let us continue to pursue wisdom about nature and do so humbly as he would—for as Freeman told me on many occasions, "nature has more imagination than we do!"
LEE SMOLIN
Physicist, Perimeter Institute; Author, Einstein's Unfinished Revolution
I met Freeman Dyson when I began my first postdoc at the Institute for Advanced Study in September of 1979. He invited me to lunch and after that we were friendly. What impressed me then was his absolutely delightful intelligence which led him to express ideas and views on a vast and surprising range of subjects. These emerged from his quiet conversations with such regularity that it seemed to some of us that imaginative thinking was for him something like "turning on a tap" and delighting in the freshness of the spring water that emerged. And I don’t think I’ve known someone who expressed more often his delight at being alive.
He was childlike but never childish. One never heard a word from him that was arrogant or was aimed at diminishing someone else (when diminishing other scientists seemed almost the purpose of conversation in that competitive atmosphere of the IAS). He seemed on first meeting to look at the world with the innocence of a child, but it quickly became clear Freeman was a man who had seen much and had distilled from it wisdom not often to be directly expressed. When he disagreed with you, you anyway learned a lot because his reasons and arguments were so surprising. So, whether it was physics, why it would have been better if Germany had got the bomb first and then lost the war or, much later, climate change, a conversation with Freeman would never end up where you thought it should go.
Back in the early 1980s, when the talk among the physicists of Princeton was all about nuclear weapons policy, he seemed to us students and postdocs to be the only one of the old guys who told the straight truth. While readily acknowledging that he was a member of the JASON consulting group, he drew our attention to the issues they had been quite wrong on, on which their advice had led, or might have led, to catastrophe, such as the contemplated use of nuclear weapons in Viet Nam, the "electronic battlefield," the US negotiating stance on multiple warheads, etc.
As my time at the Institute went on, I began to perceive that there had been a dark side. It slowly began to dawn on me, without anyone saying so, that Freeman was the trusted keeper of many secrets, personal and otherwise, from earlier times.
When he began to write, he opened his first book by sharing the earliest horrible secret he had had to keep, as a teenage mathematician doing research for bomber command, which was what proportion of Lancaster crews would survive their missions and how much of that was due to faulty design of the Lancaster’s escape hatches. Later he tried and failed to convince the British government that many fewer planes would get shot down if they simply removed the guns and gun turrets.
But in the '80s, he seemed to me and my friends as someone hopelessly entangled in contradiction. How could someone be, as Freeman told us he was, a Quaker and a pacifist, while spending his summers with the intellectuals of the air force planning strategies for nuclear war? Not to mention Project Orion, the most fabulous of his inventions, which would have accelerated huge spaceships off the earth, on their way to Mars, Saturn and beyond, on the force of dozens of thermonuclear explosions.
Freeman never seemed stressed or in a hurry, but somehow, he did—on top of all that—as much science of the first importance as would now take three or four of the best people in my generation.
Any sketch of his biography includes the often-told Greyhound bus story in which he drove out west in 1947 as Feynman’s passenger, with Feynman expounding the new way he had to formulate the quantum theory of light. Almost immediately Freeman turned around and took the bus back east. Feynman’s approach was very hard to emulate. It was said of him that his research method was simply to stare at a problem for a few minutes, after which he wrote down the right answer. Riding the bus, Freeman all of a sudden understood that Feynman’s theory was completely equivalent to older theories. That "tour de force" calculation and proof (that he visualized so clearly, he didn’t have to write it down or check it), won him his initial reputation and his permanent position at IAS—but that was only the beginning.
In the 1950s and 1960s he did important work on the quantum theory of many body systems, making him a master of both particle physics and condensed matter physics.
In the 1960s he founded a field by an utterly playful, but brilliant revelation.
In quantum mechanics we want to predict the possible energies a system might have, which is called the spectrum. Imagine we have a large atomic nucleus, with perhaps a hundred protons and neutrons. The input is all the different forces between each pair of particles, these are summarized in a large table, or array, of numbers (a spreadsheet for the younger readers) called "the Hamiltonian." The more particles the system has, the larger and more complex is this array of numbers. And the energy levels we want to compute are generally complicated functions of the entries in the table of numbers making up the Hamiltonian.
Traditionally a physicist would address such a problem by a series of steps, the first of which is to drastically simplify it—say to nuclei containing only two particles-the deuteron. If you can solve that, you try adding in a third particle—then a fourth and so on. Unfortunately, if the forces are strong, as they are in the atomic nucleus, this doesn’t get us very far past two particles.
Freeman took the opposite road: start with an infinite number of particles and work backwards from there. This has a chance, Freeman explained, because in the context of an infinite number of forces, between an infinite number of particles, the details of the actual force between any particular pair of particles shouldn’t matter much. So…let’s just assume the entries in the array are all random numbers… (impish grin, gentle eyes regarding yours: do you get the joke yet?) The joke is that in only a few steps you can compute the spectrum of an infinite random matrix.
The trick, which Freeman somehow perceived, is that you have to imagine the energies in the spectrum as if they were beads arranged on a necklace, where each bead has a small bit of electric charge attached to it. Then the answers just fall out. And, the luck of the angels, atomic nuclei, and other very large complex quantum systems have spectra that actually behave exactly that way.
The lesson from Freeman is that "if you can’t solve a big complex system, make it bigger and more complex, 'til it becomes so simple that you can solve it." Some of my best contemporaries built their careers on this insight. I myself have used Freeman’s trick to solve problems in quantum gravity, string theory, and foundations of quantum theory.
While Freeman was introducing highly technical tools into hard core physics he was thinking about many very different kinds of questions:
Do the fundamental constants vary in time?
A question we still don’t know the answer to.
How did life start?
He didn’t solve that puzzle either, no one has, but he wrote a book that remains one of the best introductions to how to think about the origin of life.
Will life go on forever, or must it die off as the universe expands and cools and the stars die?
Freeman wrote the first serious study of these questions and by doing so founded a field-cosmological biology.
Freeman used to proudly claim to be a conservative scientist, but without seeming to try, he was the most radical thinker of his generation.
There are many, many more of his inventions, questions and discoveries I could describe to cement the picture of Freeman as a contradiction with angel’s wings but let me close with my personal favorites.
Could the earth itself serve as a detector for gravitational waves, whose passage would be marked by increased worldwide seismic activity?
Could we build a detector that could count gravitons (quantum particles of the gravitational field) the same way a photocell counts photons?
The answer to the first is yes, but the second turns out to be not possible.
Much later I came to understand that Freeman was the epitome of what used to be called the "greatest generation," certainly for the accomplishment of their enormous discoveries, but even more for what they did and kept secret from us, so that we—their children—wouldn’t have to experience the violence they lived through. And just now, when I heard the news of his death, my very first thought was that they and we have been wrong. The secrets they kept from us, in their fond hopes that we preserve the innocence they never had a chance to inhabit, are exactly what we now have to quickly learn—and without them.
I already miss Freeman.
JOHN BROCKMAN
Editor, Edge
On February 3, 2019, Freeman Dyson wrote to me in response to my interest in commissioning him to write a new essay for Edge:
From: Freeman Dyson
Dear John,
Thank you for your message of January 2 announcing your new agenda and including the piece from George.
I have written a piece with the title, "Biological and Cultural Evolution: Six Characters in Search of an Author'', which I am offering for you to publish. I have adopted the design of Pirandello's play to introduce my six characters. The purpose is to give a public hearing to some unorthodox ideas about evolution.
Evolution is a dominating force in human affairs and in the workings of nature. An improved understanding of evolution may help us to deal wisely with human problems and also with the preservation of natural diversity.
Please let me know whether you find this piece appropriate for your new agenda. I send you a first draft. It will need some editorial work and some references to the literature before it is published.
I am sending you the text by a separate E-mail. With thanks for your consideration, yours ever, Freeman.
Freeman at that time was in La Jolla, and we were unable to sit down together for a videotaped interview. Nor would there be an audio. I asked if he could read the essay, and he agreed. A few days after sending him a USB microphone, my associate Russell Weinberger received an audio file with this note:
Thank you for your help this morning with the audio transfer. I could never have done this without guidance from both you and Imme. We sent it to you as soon as it was finished without checking the quality. I suspect the quality may be poor, since I was struggling with the GarageGang, a computer program that I still do not understand. If you find the quality unacceptable, I will be happy to do the whole recording over again. This will not take so long, now that we have some experience with the technical problems. In any case, I apologize for my incompetence in dealing with computers. Yours, Freeman Dyson.
Freeman, at the age of 96, had gone back to school to spend three days mastering the intricacies of Apple's "GarageGang."
So, we are pleased to reprise his essay, "Biological and Cultural Evolution: Six Characters in Search of an Author." But, do yourself a favor. While the text of the essay is available on Edge, don't read it. Honor Freeman by listening to it: a wonderful way to spend an hour.
August 1939
