Quanta Magazine https://www.quantamagazine.org/a-math-puzzle-worthy-of-freeman-dyson-20140326/ March 26, 2014 A ‘Rebel’ Without a Ph.D. A conversation with the mathematical physicist Freeman Dyson on quantum electrodynamics, climate change and his latest pet project. By Thomas Lin Freeman Dyson — the world-renowned mathematical physicist who helped found quantum electrodynamics with the bongo-playing, Nobel Prize-winning physicist Richard Feynman and others, devised numerous mathematical techniques, led the team that designed a low-power nuclear reactor that produces medical isotopes for research hospitals, dreamed of exploring the solar system in spaceships propelled by nuclear bombs, wrote technical and popular science books, penned dozens of reviews for The New York Review of Books, and turned 90 in December — is pondering a new math problem. “There’s a class of problem that Freeman just lights up on,” said the physicist and computational biologist William Press , a longtime colleague and friend. “It has to be unsolved and well-posed and have something in it that admits to his particular kind of genius.” That genius, he said, represents a kind of “ingenuity and a spark” that most physicists lack: “The ability to see further in the mathematical world of concepts and instantly grasp a path to the distant horizon that’s the solution.” Press said he’s posed a number of problems to Dyson that didn’t “measure up.” Months and years went by, with no response. But when Press asked a question about the “iterated prisoner’s dilemma,” a variation of the classic game theory scenario pitting cooperation against betrayal, Dyson replied the next day. “It probably only took him a minute to grasp the solution,” Press said, “and half an hour to write it out.” Together, they published a much-cited 2012 paper in the Proceedings of the National Academy of Sciences . The next year, Press traveled to Princeton, N.J., for a two-day celebration of Dyson at the Institute for Advanced Study, Dyson’s intellectual home for the past six decades. In honor of Dyson’s 90th birthday, there was seemingly boundless cake, a forest of long, white candles, 350 guests — including his 16 grandchildren — and lectures recognizing his eclectic achievements in math, physics, astronomy and public affairs. H. T. Yau of Harvard University commenced the math section, launching into Dyson’s work on the universality of random matrices . George Andrews of Pennsylvania State University and Kathrin Bringmann of the University of Cologne followed with the implications of Dyson’s early contributions to number theory, which he began contemplating in high school. William Happer , a physicist at Princeton University and a fellow skeptic of the perils of anthropogenic climate change, closed day one with a talk provocatively titled “Why Has Global Warming Paused?”
Transcript
Quanta Magazine
https://www.quantamagazine.org/a-math-puzzle-worthy-of-freeman-dyson-20140326/ March 26, 2014
A ‘Rebel’ Without a Ph.D.A conversation with the mathematical physicist Freeman Dyson on quantum electrodynamics,climate change and his latest pet project.
By Thomas Lin
Freeman Dyson — the world-renowned mathematical physicist who helped found quantumelectrodynamics with the bongo-playing, Nobel Prize-winning physicist Richard Feynman and others,devised numerous mathematical techniques, led the team that designed a low-power nuclear reactorthat produces medical isotopes for research hospitals, dreamed of exploring the solar system inspaceships propelled by nuclear bombs, wrote technical and popular science books, penned dozensof reviews for The New York Review of Books, and turned 90 in December — is pondering a newmath problem.
“There’s a class of problem that Freeman just lights up on,” said the physicist and computationalbiologist William Press, a longtime colleague and friend. “It has to be unsolved and well-posed andhave something in it that admits to his particular kind of genius.” That genius, he said, represents akind of “ingenuity and a spark” that most physicists lack: “The ability to see further in themathematical world of concepts and instantly grasp a path to the distant horizon that’s the solution.”
Press said he’s posed a number of problems to Dyson that didn’t “measure up.” Months and yearswent by, with no response. But when Press asked a question about the “iterated prisoner’sdilemma,” a variation of the classic game theory scenario pitting cooperation against betrayal, Dysonreplied the next day. “It probably only took him a minute to grasp the solution,” Press said, “and halfan hour to write it out.”
Together, they published a much-cited 2012 paper in the Proceedings of the National Academy ofSciences.
The next year, Press traveled to Princeton, N.J., for a two-day celebration of Dyson at the Institutefor Advanced Study, Dyson’s intellectual home for the past six decades. In honor of Dyson’s 90thbirthday, there was seemingly boundless cake, a forest of long, white candles, 350 guests —including his 16 grandchildren — and lectures recognizing his eclectic achievements in math,physics, astronomy and public affairs. H. T. Yau of Harvard University commenced the math section,launching into Dyson’s work on the universality of random matrices. George Andrews ofPennsylvania State University and Kathrin Bringmann of the University of Cologne followed with theimplications of Dyson’s early contributions to number theory, which he began contemplating in highschool. William Happer, a physicist at Princeton University and a fellow skeptic of the perils ofanthropogenic climate change, closed day one with a talk provocatively titled “Why Has GlobalWarming Paused?”
https://www.quantamagazine.org/a-math-puzzle-worthy-of-freeman-dyson-20140326/ March 26, 2014
Dyson’sunfinished science fiction story, “Sir Phillip Roberts’s Erolunar Collision,” written in the early 1930swhen he was 8 or 9.
Dyson admits to being controversial when it comes to climate science. But during an hour-longinterview with Quanta Magazine in December, he said: “Generally speaking, I’m much more of aconformist.” Still, he has written fondly of science as an act of rebellion. In his 2006 anthology ofessays and reviews, “The Scientist as Rebel,” Dyson writes, “I was lucky to be introduced to scienceat school as a subversive activity of the younger boys.” With characteristic concern for social issues,he goes on to advise parents: “We should try to introduce our children to science today as a rebellionagainst poverty and ugliness and militarism and economic injustice.”
On the second day of the 2013 celebration in Princeton, after numerous speakers had recounted pastcollaborations with Dyson, alternately feting and roasting his brilliance, Press took a different tack.Referring to their collaboration on the prisoner’s dilemma, Press — a professor at the University of
https://www.quantamagazine.org/a-math-puzzle-worthy-of-freeman-dyson-20140326/ March 26, 2014
Texas, Austin — said he “thought it would be a little extreme to reminisce with Freeman about apaper that was just published.” Instead, he described his own recent result on safer “adaptive”clinical trials, adding that although he had solid computational data, the mathematical analysisproved too formidable. “I wish I had worked on it with Freeman — and maybe still will get thechance to do so,” he said slyly.
Press’ comment proved prescient. After the celebration, Dyson began mulling over the problem —unbeknownst to Press, who didn’t find out until Quanta contacted him in March about the new“collaboration.” “I’m glad to know it’s on his stack of things to do!” he said. “I’m looking forward toseeing what he comes up with.”
Quanta Magazine interviewed Dyson at the institute, just days after his 90th birthday. An edited andcondensed version of the conversation follows.
QUANTA MAGAZINE: Technically, you retired from the Institute for AdvancedStudy 20 years ago. What are you working on now?
FREEMAN DYSON: I used to be a scientist and did a lot of calculations. It was a competitive world,and when I got older, I decided I wouldn’t compete with the bright, young people anymore, so I writebooks instead. And now I’ve become a book reviewer for The New York Review of Books. About oncea month, I write a review, and then I get a lot of response and correspondence, people who arefinding things I said which aren’t true.
What did you do prior to writing book reviews?
I was trained as a mathematician, and I remain a mathematician. That’s really my skill, just doingcalculations and applying mathematics to all kinds of problems, and that led me into physics firstand also other fields, such as engineering and even a bit of biology, sometimes a little bit ofchemistry. Mathematics applies to all kinds of things. That’s one of the joys of being amathematician.
Why math?
I think the decisive moment was reading the book “Men of Mathematics” by Eric Temple Bell. Bellwas a professor at Caltech, and he wrote this book, which is actually just a wonderful collection ofbiographies of mathematicians. Historians condemn it as romanticized. But what was wonderfulabout this book is that he showed the mathematicians as being mostly crooks and people of verymixed kinds of qualities, not at all saints, and many of them quite unscrupulous and not very clever,and still they managed to do great mathematics. So it told a kid that “if they can do it, why can’tyou?”
What are some of the big questions that have guided your career?
I’m not a person for big questions. I look for puzzles. I look for interesting problems that I can solve.I don’t care whether they’re important or not, and so I’m definitely not obsessed with solving somebig mystery. That’s not my style.
What kinds of puzzles first intrigued you?
I started out as a pure mathematician and found problems that just arise out of the very nature ofnumbers, which are amazingly subtle and difficult and beautiful. That was when I was about 17 orso, just at the end of high school. I was interested in numbers before I was interested in the real
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world.
What is it about numbers that made you want to figure them out?
It’s just like asking, “Why does a violinist like to play the violin?” I had this skill with mathematicaltools, and I played these tools as well as I could just because it was beautiful, rather in the same waya musician plays the violin, not expecting to change the world but just because he loves theinstrument.
You’re known for your work in quantum electrodynamics — which describesinteractions between light, matter and charged particles — and in solving therenormalization problem — which helped rid the mathematics of unwantedinfinities. How did that work come about?
When I arrived in Cornell in 1947, there just had been done a beautiful experiment at Columbia onthe hydrogen atom. The hydrogen atom is the simplest atom, and you ought to be able to understandit if you understand atoms at all. So, these experiments were done by Willis Lamb and his studentRobert Retherford at Columbia, observing for the first time the very fine behavior of hydrogen usingmicrowaves to examine the hydrogen atoms, and Lamb got very precise results. The problem wasthe quantum theory wasn’t good enough to explain his results. Dick Feynman, who was an absolutegenius, had understood more or less how to explain it but couldn’t translate his ideas into ordinarymathematics. I came along and had the mathematical skill, making it possible to calculate preciselywhat the hydrogen atom was doing, and the amazing thing was that my calculations all agreed withthe experiment, so it turns out the theory was right.
I didn’t invent anything new — I translated Feynman’s ideas into mathematics so it became moreaccessible to the world, and, as a result, I became famous, but it all happened within about sixmonths.
Did it lead to other questions that you wanted to explore?
I got job offers from everywhere in America and also in England, but the problem was that I didn’tactually want to settle down yet and become an overburdened professor with lots of students. So Iescaped to England and had two happy years at Birmingham without any responsibilities andcontinued working on other problems.
I was very much interested in space travel, and so the next exciting thing I did was to work with acompany in California called General Atomics for a couple of years building a spaceship. In thosedays, people were willing to take all kinds of risks, and all kinds of crazy schemes got supported. Sothere was this bunch of crazy, young people — the leader was Freddie de Hoffmann, who had beenat Los Alamos [National Laboratory] and knew all about nuclear bombs — and we decided we wouldgo around the solar system with a spaceship driven by nuclear bombs. We would launch the ship intospace — “bomb, bomb, bomb, bomb,” about four bombs per second — going up all the way to Marsand then afterwards to Jupiter and Saturn, and we intended to go ourselves.
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Freeman and Imme Dyson traveled to the Baikonur Cosmodrome in Kazakhstan in March 2009 forCharles Simonyi’s second trip to the International Space Station.
What happened to Project Orion?
I spent two wonderful years in San Diego having grand dreams of spaceships. We not only didcalculations, we also flew little models about a meter in diameter with chemical explosives, whichactually went “bomb, bomb, bomb, bomb” a few times a few hundred feet up. It was amazing wenever got hurt. I think we didn’t even have to buy the explosives. We had some Navy friend whostole it from the Navy. Anyhow, we certainly borrowed the test stand from the Navy where we didthese little flight tests. That lasted for two years. By that time, it was clear that the competition wasactually going to win, the competition being Wernher von Braun and the Apollo program, which wasgoing to go with ordinary rockets to the moon.
The Orion spaceship sounds like something a child might dream up. Howdisappointed were you that this “grand dream” wasn’t realized?
Of course we were very disappointed when it turned out that the Orion never flew, but it was clearthat it would make a horrible mess of the landscape. These bombs were producing radioactivefallout as they went up through the atmosphere, and although at that time we were exploding bombsin the atmosphere for military purposes, which were much bigger than the ones we proposed to use,still we would have made a contribution to the general contamination, and that was the reason whythe project failed, and I think it was a good reason.
You’ve developed a reputation as a maverick scientist with contrarian views.Where do you think that comes from?
I think the notion that I always like to oppose the consensus in science is totally wrong. The fact isthere’s only one subject that I’ve been controversial, which is climate. I spend maybe 1 percent ofmy time on climate, and that’s the only field in which I’m opposed to the majority. Generallyspeaking, I’m much more of a conformist, but it happens I have strong views about climate because Ithink the majority is badly wrong, and you have to make sure if the majority is saying something thatthey’re not talking nonsense.
With a majority of scientists on the other side of this issue, what would it taketo convince you to switch sides?
What I’m convinced of is that we don’t understand climate, and so that’s sort of a neutral position.I’m not saying the majority is necessarily wrong. I’m saying that they don’t understand what they’reseeing. It will take a lot of very hard work before that question is settled, so I shall remain neutraluntil something very different happens.
You became a professor at Cornell without ever having received a Ph.D. Youseem almost proud of that fact.
Oh, yes. I’m very proud of not having a Ph.D. I think the Ph.D. system is an abomination. It wasinvented as a system for educating German professors in the 19th century, and it works well underthose conditions. It’s good for a very small number of people who are going to spend their livesbeing professors. But it has become now a kind of union card that you have to have in order to havea job, whether it’s being a professor or other things, and it’s quite inappropriate for that. It forcespeople to waste years and years of their lives sort of pretending to do research for which they’re not
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at all well-suited. In the end, they have this piece of paper which says they’re qualified, but it reallydoesn’t mean anything. The Ph.D. takes far too long and discourages women from becomingscientists, which I consider a great tragedy. So I have opposed it all my life without any success atall.
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summer of 1955, below Yosemite Falls in California.
How is it that you were able to escape that requirement?
I was lucky because I got educated in World War II and everything was screwed up so that I couldget through without a Ph.D. and finish up as a professor. Now that’s quite impossible. So, I’m veryproud that I don’t have a Ph.D. and I raised six children and none of them has a Ph.D., so that’s mycontribution.
Looking back at your career, how has your approach to science changed overthe decades?
I’ve now been active for something like 70 years, and still I use the same mathematics. I think themain thing that’s changed as a result of computers is the magnitude of databases. We now havethese huge amounts of data and very little understanding. So what we have now — I forget who itwas who said this — are small islands of understanding in a sea of information. The problem is toenlarge the islands of understanding.
What scientific advance do you see on the horizon that will have a big impacton society?
People are often asking me what’s going to happen next in science that’s important, and of course,the whole point is that if it’s important, it’s something we didn’t expect. All the really importantthings come as a big surprise. There are many examples of this, of course, dark energy being thelatest example. Anything I mention will be something that, obviously, is not a surprise.
Are you currently working on a math problem?
The question of what I do with my time is a delicate one. I’m not really doing science competitively,but I like to have a problem to work on. I’m very lucky to have a friend, Bill Press, who is an experton clinical trials, which actually turns out to be an interesting mathematical problem.
He published a paper explaining how to do clinical trials in a really effective way with a minimumloss of life. He’s a computer expert, so everything he does is worked out just with numbers, and so Ihave taken on as my next task to translate what he did into equations, the same way I did withFeynman. I’m not sure whether it will work, but that’s what I’m thinking about at the moment.
What does it mean for someone with so many intellectual pursuits to beretired?
When I retired as a professor of the institute, I kept all the privileges. The only thing that changed isthe paychecks stopped coming. I still have an office and all the secretarial help I need, plus a placeat the lunch table. One more advantage is not having to go to faculty meetings.
