Brenner, von Neumann and Schrödinger

Erwin Schrödinger's book, "What is Life"?, inspired many scientists like Crick, Watson and Perutz to go into molecular biology. While many of the details in the book were wrong, the book's central message that the time was ripe for a concerted attack on the structure of the genes based on physical principles strongly resonated.

However, influence and importance are two things, and unfortunately the two aren't always correlated. As Sydney Brenner recounts in detail here, the founding script for molecular biology should really have been John von Neumann's 1948 talk at Caltech as part of the Hixon Symposium, titled "The General and Logical Theory of Automata". In retrospect this talk was seminal and far-reaching. Brenner is one of the very few scientists who seems to have appreciated that von Neumann's influence on biology was greater than Schrödinger's and that von Neumann was right and Schrödinger wrong. Part of the reason was that while many biologists like Crick and Watson had read Schrödinger's "What is Life?", almost nobody had read von Neumann's "General and Logical Theory of Automata".

As Brenner puts it, Schrödinger postulated that the machinery for replication (chromosomes) also included the means of reproducing it. Von Neumann realized that the machinery did not include the means themselves but only the *instructions* for those means.

That's a big difference; the instructions are genes, the means are proteins. In fact as Freeman Dyson says in his "Origins of Life", von Neumann was the first to clearly realize the distinction between software (genes) and hardware (proteins). Why? Because as a mathematician and a generalist (and pioneer of computer science), he had a vantage point that was unavailable to specialist biologists and chemists in the field.

Unfortunately abstract generalists are often not recognized as the true originators of an idea. It's worth noting that in his lecture, von Neumann laid out an entire general program for what we now call translation, five years before Watson, Crick, Franklin and others even solved the structure of DNA. The wages of the theoretician are sparse, especially those of the one, as mathematician John Casti put it, who solves "only" the general case.

The last great contrarian?

Freeman Dyson, photographed in 2013 in his office by the author

On February 28th this year, the world lost a remarkable scientist, thinker, writer and humanist, and many of us also lost a beloved, generous mentor and friend. Freeman Dyson was one of the last greats from the age of Einstein and Dirac who shaped our understanding of the physical universe in the language of mathematics. But what truly made him unique was his ability to bridge C. P. Snow’s two cultures with aplomb, with one foot firmly planted in the world of hard science and the other in the world of history, poetry and letters. Men like him come along very rarely indeed, and we are unfathomably poorer for his absence.

The world at large, however, knew Dyson not only as a leading scientist but as a “contrarian”. He didn’t like the word himself; he preferred to think of himself as a rebel. One of his best essays is called “The Scientist as Rebel”. In it he wrote, “Science is an alliance of free spirits in all cultures rebelling against the local tyranny that each culture imposes on its children.” The essay describes pioneers like Kurt Gödel, Albert Einstein, Robert Oppenheimer and Francis Crick who cast aside the chains of conventional wisdom, challenging beliefs and systems that were sometimes age-old, beliefs both scientific and social. Dyson could count himself as a member of this pantheon.

Although Dyson did not like to think of himself as particularly controversial, he was quite certainly a very unconventional thinker and someone who liked to go against the grain. His friend and fellow physicist Steven Weinberg said that when consensus was forming like ice on a surface, Dyson would start chipping away at it. In a roomful of nodding heads, he would be the one who would have his hand raised, asking counterfactual questions and pointing out where the logic was weak, where the evidence was lacking. And he did this without a trace of one-upmanship or wanting to put anyone down, with genuine curiosity, playfulness and warmth. His favorite motto was the founding motto of the Royal Society: “Nullius in verba”, or “Nobody’s word is final”.

Many chapters from Dyson’s own life illustrate this spirit of rebellion; some of it was by choice, some by necessity. First was his rebellion from pure mathematics. Dyson had learnt mathematics from G. H. Hardy, a man for whom the purity of mathematics was so sacred that, in a short and beautifully written book, he said he was actually proud of working on things that had absolutely no practical use. Dyson learnt mathematics from Hardy during the cold, dark days of the Second World War, when most of the students at Cambridge University had left to fight and Hardy taught a handful of students including Dyson in his rooms. Decades later Dyson could remember the tired, shrunken figure of Hardy lecturing from his chair, with the 17-year-old occasionally feeling like giving the old man a hug. Hardy imparted Dyson with a genuine love for the beauty of mathematics, and while Dyson worked on an astonishing variety of pure and applied problems during the rest of his life, his first love never left him and he kept coming back to it; when I attended his 90th birthday celebrations six years ago, about a third of the talks were about his occasional escapes into mathematics and the flowers they sprouted in other people’s gardens.

As war raged on the continent, Dyson was once taking a walk with a friend of his, the Indian mathematician Harish-Chandra who later became his colleague at the Institute for Advanced Study in Princeton. Harish-Chandra had started as a physicist, studying under Paul Dirac. Dyson had already started getting a taste of applied mathematics, working for Bomber Command where he was using statistics to figure out the most effective way to bomb Germany into surrender. “I am planning to leave physics for mathematics”, said Harish-Chandra. “I find physics to be unrigorous, messy, elusive”. “Interesting”, replied Dyson. “I am planning to leave mathematics for physics for exactly the same reasons.” Dyson was farseeing, and while mathematics would continue to be a rich source of discoveries, he could see that it was physics that was becoming the most promising discipline then. The atomic bomb, which as far as most people were concerned had won the war, sealed the decision in his mind to become a physicist and told him that physics and America were where the action was.

But Dyson was not even the most unconventional figure in this regard. Right after the war he ran into Francis Crick who had spent a depressing time during the war working on magnetic mines for the British admiralty. He was just then planning to switch to biology and join the famous Cavendish Laboratories where researchers under the physicist Lawrence Bragg were working on deciphering the structures of proteins. Bragg himself was one of the pioneers of x-ray crystallography and had decided to change the Cavendish’s direction, from its early pioneering work in physics under J. J. Thomson and Ernest Rutherford to new research in biology. When Dyson met Crick he explained his decision to switch to biology. Dyson told him biology was interesting but it was too early to be able to make major contributions to it. As Dyson recalled, he was happy that Crick disregarded his advice and went on to become perhaps the most important biologist of the 20th century, not only cracking the structure of DNA but deciphering the genetic code and influencing an entire generation of molecular biologists. I tell these stories to make the point that while Dyson was certainly an unconventional mind himself, it helped quite a bit that he was surrounded by equally unconventional and odd minds during his formative years as a student, people who switched fields with impunity and worked on completely new things. One might in fact argue that Cambridge was then a breeding ground for contrarians; in the next decade or two it would house minds like Thomas Gold, Fred Hoyle, Roger Penrose and Stephen Hawking, all known for the audacity and unconventional nature of their ideas.

This spirit of rebellion stayed with Dyson as he moved to the United States and started his apprenticeship under the tutelage of Hans Bethe, the legendary physicist who won a Nobel Prize for working out how the stars shine and led the theoretical physics division of the Manhattan Project. At Cornell where Bethe held court, Dyson met an even freer spirit, Richard Feynman. Dyson’s great mathematical skills were ideally suited to understand the new realm of quantum electrodynamics which Feynman, wunderkind Julian Schwinger and others were trying to understand. On a cross-country drive which became the stuff of folklore, Dyson had the unique opportunity to hear first Feynman’s version of his theory and then Schwinger’s of his, two versions which seemed irreconcilable. Dyson would show that they were two ways of looking at the same physical reality.

Years later Dyson would write a memorable essay called “Birds and Frogs”: some mathematicians are frogs who like to play in the mud and solve problems, he would say. Others are birds who soar and survey the landscape from a great height. Although he put himself squarely in the camp of frogs, the crucial work he did bridging Feynman and Schwinger’s theories and providing a unified view of quantum electrodynamics made him a bird. Throughout his life he was able to expertly navigate between the two domains.

Dyson was unconventional not just in his science but in his view of the social aspects of science, a view that he applied to himself with abandon. He famously never received a PhD; by that time it had become clear that he did not need one. Without a PhD the prodigy became a professor at Cornell and a fellow of the Royal Society, both before he turned 30. Over the years, dozens of PhD theses would be written based on Dyson’s work, but he would become a sharp critic of the entire system, a view that seems increasingly valid in an age when graduate students and postdoctoral researchers are often regarded as a source of cheap labor to grind out results and papers. Dyson thought that the PhD had become a kind of union card, forcing students and especially women who might want to start a family to spend most of their twenties working on single problems so that they would be deemed worthy enough to join a hallowed guild. It is also unfair to inventors who almost never have a PhD. I have worked with both PhDs and non-PhDs during my career and on balance can say that the non-PhDs have been more approachable, more hardworking and more creative. Unfortunately our research system, both in academic and industry, puts a premier on people having PhDs.

With his lack of a PhD and his disdain for a system that forces both students and professors to spend years working on a problem, Dyson the frog clearly realized that he wasn’t suited to a conventional academic career. But it also made him reassess what his particular strengths were. His great accomplishment had given him an enviable lifetime appointment at the Institute for Advanced Study in Princeton; Robert Oppenheimer who was the director had himself sung Dyson’s praises. For the next seven decades Dyson would become one of the most famous residents of the institute, but even his home institution was not spared from his contrarian take. He always thought the institute was too ivory tower and too much like an alien transplant in America– in contrast Ithaca and Cornell where he had lived before were the real American deal. He also disdained the tribalism among the institute’s mathematicians and their successful efforts to shut down John von Neumann’s computer project, a project which if it had been supported would have put the IAS on the map in the annals of modern computing.

During the early years Dyson kept on working on particle physics which had been his first proving ground, but a high water mark in Dyson’s career as a particle physicist came when he had a fortuitous meeting with Enrico Fermi in Chicago in 1953. Dyson and his students at Cornell were working on some results on particle scattering which seemed to give very good agreement with experiments done by Fermi. Fermi demolished the agreement in one fell swoop, saying that Dyson had neither a consistent mathematical theory nor a clear physical picture to explain the results. As far as the good curve fitting between theory and experiment was concerned, he quoted his friend Johnny von Neumann; with four parameters one can fit an elephant to a curve, with five one can make him wiggle his trunk. The conversation with Fermi, barely lasting fifteen minutes, dashed Dyson’s hopes to be a conventional physicist of high caliber. But his frustration was actually an astute observation and an epiphany: Fermi was the epitome of what a great physicist was supposed to be, combining great facility at experimentation and visualization of the physical picture with an equally good facility at calculation. Dyson’s forte was calculation.

It was partly the meeting with Fermi that convinced Dyson that his great strength was to apply mathematics to diverse problems rather than make great advances in what was then most fashionable in physics. This cleared the way for a remarkable career. His contributions in quantum electrodynamics were important enough, but after that Dyson switched to other fields, in particular condensed matter physics. In this realm his most important contribution concerned a fundamental question that can be asked simply: if most of the atom is empty space, what makes ordinary matter stable? Using a laborious proof that only one who was skilled in the highest realms of mathematical manipulation could muster, Dyson proved that the Pauli exclusion principle which prevents two electrons from occupying the same quantum state essentially keeps electrons apart and makes matter stable. The proof involved pages of hairy mathematics and was improved later by other researchers, but it did demonstrate Dyson’s great strengths as a professional calculator without peer. It also cemented his reputation as someone who would regularly toss gems aside that others would pick up and build into great edifices.

Until then, whatever some of the contrarian turns he took, Dyson was still known primarily as a theoretical physicist working in diverse parts of physics. But it was his work in the 1950s on engineering problems that truly demonstrated not only the scope of his intellect but the wondrous ambition of his ideas. The first engineering project he worked on was to design a nuclear reactor with physicist Edward Teller and others which would be intrinsically safe and “idiot-proof”; the safety in the reactor would have to come not from decisions by the operator but from the laws of physics. This reactor would be designed by collaboration between physicists, chemists and engineers. Dyson had to essentially learn an entire field of engineering, but at that time there were no true experts so the scientists who had gathered in a former red schoolhouse in La Jolla taught each other. The result of their deliberations was the TRIGA, the only nuclear reactor which has made a profit for its company. During TRIGA’s inauguration Dyson got a chance to take a solitary walk on the beach with the great Niels Bohr himself, but Bohr’s famous mumble and soft voice kept Dyson from receiving any enlightenment.

If TRIGA was earth, Project Orion was heaven. Buoyed by the enthusiasm of space travel, nuclear energy and rocketry in the 1950s, a small group of dreamers decided to build a spaceship powered by nuclear bombs. The idea was to sequentially explode bombs at a distance under a pusher plate on a spaceship and let the momentum carry the rocket away at great speed. “Saturn by 1970” was their motto, and it would also be a nice way to get rid of all those dangerous nuclear weapons lying around. Project Orion tested Dyson’s faculties and allowed his imagination to soar like nothing else. Once again we see the scientist as rebel, applying his skills to an audacious idea which had never before been explored and which could lead to a brave new world. The engineers on Project Orion remember being astonished by Dyson’s versatility as they saw a pure theoretical physicist calculate friction coefficients and load ratios, visualizing giant bombs going off under giant spaceships; while the project initially used small, tactical nuclear weapons, Dyson later imagined bigger, fusion-based weapons propelling the craft. A colleague named Brian Dunne captured Dyson’s unique style:

Freeman doesn’t have the Handbuchderphysik, the last-word sort of German precision. He doesn’t have the French quality of slap-dash, a point here well taken but the rest of it wrong. He doesn’t have the stiff British restraint. It’s a style he has developed that’s all his own.

Project Orion came to an end when radioactive fallout became a public concern and the test ban treaty of 1963 banned nuclear explosions in the atmosphere, but it had been a wild ride for this unconventional thinker. It was also an act of rebellion in another regard: ever since he hired him at the institute in Princeton, Robert Oppenheimer had thought that Dyson would continue his work on the purest of fundamental physics that Oppenheimer thought was the only thing worth doing. While forays into other areas of physics and nuclear engineering utilized Dyson’s abilities handsomely, Oppenheimer made it clear that he would not welcome Dyson back if he kept working on these areas for too long. Fortunately Dyson the contrarian found other ways to channel his unique abilities.

One of those ways was to think about communicating with aliens, another mainstay of 1950s and 60s interests. In 1960 Dyson wrote a serious paper in Science describing how an advanced extraterrestrial civilization might be able to disassemble a Jupiter-sized planet and surround itself with its pieces, trapping its parent star’s energy inside and utilizing it. Became these star systems would be cloaked by the shell of the planet’s fragments they would not be visible, but because they trapped energy it would escape as infrared radiation which could be detected. Unusual infrared radiation signatures could therefore be a way to find extraterrestrials. The original idea had not been Dyson’s and had been described by science fiction writer Olaf Stapledon in his story “Star Maker”, but its serious extension became emblematic of Dyson’s originality; take an audacious idea, even one that belongs to the realm of science fiction, and turn it into a serious scientific paper filled with mathematical calculations. Since the 1960 paper was published, Dyson Spheres have become a staple of modern science fiction, even making it into ‘Star Trek’.

The search for life in space was one of Dyson’s enduring interests and it gave voice to his creativity like little else. He disdained ideas like the Drake Equation that relied on highly uncertain armchair speculation without suggesting experiments. Along with Dyson Spheres, he also came up with an idea to find life on Europa by searching for freeze-dried fish in its orbit instead of water under its surface (the logic being that the former, while it sounds outlandish, is much easier to look for than the latter which involves very expensive drilling) and a way to grow giant plants in the reduced gravity of comets. But even assuming that humanity could escape the bonds that have always bound itself to planet earth, how long can life keep this up, this constant hopping around between inhospitable environments?

In Dyson’s view – literally until the end of time. In 1979, he wrote “Time Without End: Physics and Biology in an Open Universe”, perhaps his most audacious serious paper, covering thirteen pages in the distinguished journal Reviews of Modern Physics. In it he argued that living creatures could keep on feeding off dwindling sources of energy in an expanding universe and even keep communicating with each other, although admittedly not in a form that would be easily recognizable to modern day human beings. With this paper, he hoped to “hasten the arrival of the day when eschatology, the study of the end of the universe, will be a respectable scientific discipline and not merely a branch of theology.” Like all contrarians who deal with speculative ideas, Dyson was prepared to accept that this one might be incorrect. In the 1990s a new era in our understanding of the universe dawned when it was found that the expansion of the universe is accelerating. In this universe Dyson’s creatures would be doomed since they would be competing against energy sources rapidly going to zero and distances between galaxies going to infinity. Dyson graciously accepted as much in a new edition of his set of Gifford Lectures, “Infinite in all Directions”, but he still found solace: “If it turns out that we live in a constantly accelerating universe, we may complain that God designed it badly as a home for intelligent creatures, but we can be thankful that he gave us at least a few trillion years to enjoy it before the final darkness falls.”

1979 was also the year when Dyson started a new career, taking a step that is truly contrary for most working scientists. He wrote his autobiography, “Disturbing the Universe”; “Life begins at 55”, he said, because that was when he wrote his first book. Among top scientists there are very few who can write genuinely well, partly because there are very few who are genuinely steeped in both their scientific specialization as well as the broader traditions of literature. Fortunately Dyson’s upbringing had given him a unique facility with both science and the humanities – his mother was a lawyer who fought for women’s rights and his father was Sir George Dyson, one of England’s most well known composers of the time; his parents were highly cultured and socially responsible people, and they endowed Freeman with an unusual sensitivity to human affairs. He himself acknowledged his two strengths as “calculation and English prose”. Transitioning from largely doing hard science to largely doing writing and giving lectures served both Dyson and the world exceedingly well, and by doing this he was following a maxim G. H. Hardy once told him: “Young men should prove theorems. Old men should write books.”

“Disturbing the Universe” remains a remarkable book, filled not only with sharp observations on great scientists like Oppenheimer and Feynman but sprinklings from T. S. Eliot and Blake, full not just of discussions of physics and genetic engineering but reflections on world peace and human nature. It’s perhaps the finest memoir I have read of the scientist as citizen. All of Dyson’s ensuing books have mirrored these themes, combining highly original scientific ideas with meditations on war, peace and human affairs. He always saw people’s flaws astutely, but also saw their greatness and saw how both of these qualities combined to make a complete person. And he was as comfortable discussing minor but enlightening issues of family and friends, as he was the fate of the world. Most of all he cared about his family and was proud of his six children who now have sixteen children in all and are productive citizens.

Even when he was mainly writing books Dyson kept on making strikingly original contributions to science. In a 1999 interview he was asked what he thought would be his most important contribution to science. It would be hard to know until he had been dead for a hundred years, he sensibly said, and added that his son thought his contributions to the origins of life might be most important. Dyson was referring to a slim volume he had just published in which he had made the striking argument that life might have arose twice, once as pure metabolism and once as pure replication. Dyson’s starting point was Erwin Schrödinger’s equally slim book “What is Life?” and a set of lectures on self-reproducing automata that Johnny von Neumann had given in the 40s. Just like Dyson, Schrödinger and von Neumann were physicists and mathematicians who had made a side foray into biology. Just like Schrödinger’s book, Dyson’s book might stand the test of time and turn out to be an unusually important contribution. In fact recent findings of life arising by pure metabolism in hot vents under the sea could well support Dyson’s theories. This was Freeman Dyson at his best, starting multiple lines of research even during a minor trip off the beaten track into a field that he previously knew nothing about.

More original ideas followed including two from 2012 (when he was 89): one arguing that it might be impossible to detect individual gravitons and dissolve the wall between quantum theory and general relativity, and a paper on game theory that upended conventional wisdom in the field. He became somewhat controversial for arguing that extrasensory perception might be real but it may be just outside the bounds of our standard measuring equipment and experiments; I have similar feelings about traditional Chinese and Indian medicine, much of which deals with small but significant holistic effects and differs from person to person and therefore may escape the design of standard double blind clinical trials.

But in the last decade or so of his life, Dyson became most famous in the public eye because of his views on global warming. I regard this entire affair as unfortunate and blown out of proportion, more emblematic of how we have grown increasingly intolerant in recent times than of anything Dyson said or wrote. During my several meetings and email exchanges with him I discussed global warming, and he never denied the basic facts, only the consequences. I always thought that most of his views were valid and were steeped in sound skepticism and humility. He asked if we know for certain how much the good effects of climate change will outweigh the bad, and in particular whether increased CO2 might not be better for the growth of certain trees and for certain cold regions of the planet. He asked if in our zeal to criticize we are not paying attention to technological solutions that might mitigate the problem. Some of his ideas such as genetically engineering trees that might consume more CO2 were speculative, but one could argue that an extraordinary problem like climate change warrants the exploration of extraordinary ideas.

He realized that the climate is a very complex system about which it’s difficult to know everything, especially when computer modeling plays such an important role. There are some components of the climate like wind patterns that are better understood than others like the soil. One reason I very much empathized with him is because I have spent most of my career doing computer modeling on chemical systems much simpler than the climate. These systems often involve only two molecules interacting with each other, and yet we have found out how complicated modeling the action of different components in these systems are; as he and I often discussed, water especially seems to be a diabolical culprit to understand, both in cloud formation and chemical systems. I also found during our conversations that climate change is a minor interest of his, and most of the controversy seemed to be drummed up by others rather than by Dyson himself. Most of all he lamented the intense politicization of climate change that had made reasoned debate very difficult, and I could not agree more. If certain groups of individuals and groups took his views out of context and used them to shore up their own political agenda, it would be unfair to blame him for it.

When I heard about Dyson’s passing I felt devastated. Devastated not only because I had lost someone who I considered to be the biggest intellectual influence on my thinking after my father’s passing a few years ago, but because I wonder if the world is now willing to tolerate the tradition of skepticism and originality that he and fellow scientists he admired exemplified. When I hear people say that he was a contrarian, I think it should be clear that he was always a contrarian and we are all the better off for it. Being a contrarian enriched his life, took him in unexpected directions and uniquely contributed to his dialogue with the world. And if the word “contrarian” means someone who comes up with highly original ideas that challenge the status quo and bucks the trend, then Dyson was a contrarian in the best scientific tradition. He had displayed these qualities all his life, right from his transition to physics as a student to his forays in very diverse branches of science and engineering to his career as a writer of eloquent prose and his commentary on social issues. But if Dyson was the last contrarian it makes him even more unique and we are in trouble.

The reason I worry is that we increasingly seem to live in an age in which contrarian ideas of the kind Dyson exemplified are not just criticized but criticized through a moral lens. Unfortunately social media has wildly exacerbated this trend. Today when you express a contrarian view on social media, not only do people disagree with you and regard you as mistaken but they are also likely to regard you as immoral and even evil. This is a problem, and it’s a problem especially when a minority of people who are actually immoral get their opinions mixed up with those who are arguing in good faith. Moral criticism makes it much harder for individuals to speak their mind compared to criticism of other kinds. Now of course, throughout history moral judgement has been used as a tool for social ostracism, but as long as it did not expose you to the entire world it kept the criticism contained and within bounds. You may have felt a little dissuaded but you could still preach your gospel. Today when anything that you say to a small group of people can reach thousands of people on social media, when the ensuing din hounds you out of the chambers of debate, the scope of moral criticism gets tremendously magnified, magnified to such an extent that it becomes a whirlwind and silences everyone except those with unusually stout hearts.

We must return to an era when disagreements are just that, disagreements in good faith. There is too much at stake in our world today and the problems we are trying to solve are too complex to allow only one set of voices to be heard and opposing ones silenced. And because the problems are so complex, some of us will inevitably be wrong. But that’s how it should be. The best contrarians always realize that they can be wrong – Dyson once said that he would rather be wrong than be vague, and always admitted the former possibility – and it’s precisely that freedom to be wrong, the freedom to be listened to and disagreed with without moral ostracism and outrage that illuminates the path to the truth.

An old voice from Dyson’s past, his mentor Robert Oppenheimer, once said,

“There must be no barriers to freedom of inquiry. There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors…and we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress.”

I hope that if Freeman Dyson was the great contrarian, he certainly won’t be the last one.

Freeman Dyson (1923-2020): A personal remembrance

I am terribly, ineffably sad to learn that my longtime correspondent and friend Freeman Dyson has passed on to the ages at age 96. I have written quite a bit about Freeman's science, but above all it's my personal friendship and correspondence with him over more than ten years and the wisdom and kindness that he imparted that I will cherish the most and that has left an indelible impression, a profound intellectual influence and, now, a palpable gap in my life. I feel like I have lost a close member of my own family.

No doubt much will be written about this remarkable man who was one of the leading scientific and literary lights of the 20th century. His imagination and contributions ranged over an entire universe of disciplines - pure and applied mathematics, theoretical and particle physics, game theory, nuclear reactor and spaceship design, origins of life, space exploration and astrophysics, genetic engineering - whose only unifying thread seemed to be the diversity of ideas they contained. Most of these he explored in rigorous scientific papers with reams of mathematics; some of these he explored in elegant prose written for the general public. He made groundbreaking contributions to an untold variety of fields, and as evidenced on his 90th birthday celebration, even his "minor" contributions would start ten or twenty year explorations. His many books contain deep humanism and originality and speak to uncommon wisdom, and they introduced an entire generation of non-scientific readers to the wonders of science. For Freeman diversity was the predominant, celebratory feature of the universe and human life.

It seems like only yesterday, but it's been twenty years since I first saw a strange, dusty book in the recesses of the college library titled "Disturbing the Universe", written by an author whose name I had never heard. The book was utterly captivating, and it displayed both a clarity and an eloquence that I had never seen in scientific writing before. Even now it remains one of the best introductions to the mind, life and credo of a working scientist who also embodies unusual humanity and sensitivity to human affairs. In crystal clear prose and often quoting the great poets and writers, Dyson described his journey in physics, engineering, arms disarmament, genetic engineering and other fields. 

But the book is also a portrait gallery of the people he met on his way. Not only did Freeman describe his close association and friendship with many of the greats of physics - Feynman, Oppenheimer, Bethe - but it was also clear that he was part of this rarefied tribe himself. He disagreed with Oppenheimer, proved himself to be Bethe's best student and had a unifying vision of light and matter on a memorable cross-country drive with Feynman. That he was extraordinarily precocious - elected a fellow of the Royal Society and made a professor at Cornell, all without ever having a PhD before he turned 30 - was also obvious. Scientifically he would be remembered most of all as one of the architects of modern quantum electrodynamics and particle physics. It's a measure of the man's achievements that the book was written when he was only 55, so by that time he had already accomplished more than what most brilliant scientists would in their lifetimes.

But there was something else that struck me even when I first read his memoir. This Dyson was not just a brilliant mathematician and physicist but he seemed to have a rarer, more interesting streak: he seemed to actually like saying outlandish things that go against the grain, and he then took them seriously and did calculations on them! He took the idea of extraterrestrial civilizations and humanity venturing into outer space seriously, and he wrote staid scientific papers arguing for life existing limitlessly in an expanding universe. He came up with the idea of Dyson spheres and civilizations disassembling planets to capture energy, and he saw an age when people would genetically engineer their favorite plants and animals in garages. He even suggested that people should seriously investigate extrasensory perception. And he was serious when he helped build a spaceship powered by hydrogen bombs and wanted to be among the first human beings to reach Saturn by 1970.

This was my first taste of what was probably Freeman's most enduring quality: he was a contrarian and a maverick, someone who liked playing the devil's advocate, the guy who always had his hand raised in a room full of nodding heads, not because he wanted to get a rise out of people but because he believed that science best progresses not through consensus but around the edges, when people ask questions. And he played this role throughout his life with such playfulness, warmth and genuine conviction that nobody could ever hate him for it. His favorite motto was the founding motto of the Royal Society - "Nullius in verba", or "Nobody's word is final". It's the founding motto of science itself.

Fast forward to ten years ahead when I was a lowly postdoc in New Jersey. Princeton was only about fifteen miles from where I lived and Dyson worked there. Would he respond to an email? I still remember how, barely an hour after I wrote he responded: "Yes, we can meet in Princeton. I hereby invite you to lunch at the institute. Please call me so we can decide on a date." I had to pinch myself but it was true. A few minutes later I heard his soft, cordial voice on the phone and we had a meeting scheduled.

November 10, 2010: With some trepidation I remember climbing the stairs to his office at the famous Institute for Advanced Study which once housed Einstein, Gödel, Oppenheimer and von Neumann. Inside was an elfin man hunched intently at a computer. "Prof. Dyson", I asked. No response. I asked again a bit more loudly, and the man in the chair jumped two feet in the air: Freeman Dyson's powers of concentration were legendary. 

The next three hours over lunch and in his study were utterly memorable, and it felt like taking a walk through a garden of intellectual treats. I was looking fondly yesterday at some of the notes I took from our meeting (I remember darting to a cafe after leaving and furiously scribbling this down, not knowing whether I would get a chance to meet Freeman again!), and the topics were really all over the place: climate models, water in molecular models, Obama, religion, South Africa's nuclear weapons program, gravitational waves, socialism, gravitons, reading on the Kindle, getting his genome sequenced, memories of physicists Subrahmanyan Chandrasekhar and Frank Yang, education in India, books about World War 2 and poetry. He was interested in every topic, no matter how grand or how mundane, and while he has written about the big picture many times, he has always said that he is first and foremost a problem solver. For me our conversation certainly confirmed Freeman's astonishingly wide ranging mind and interests, but it also confirmed how immensely approachable and down to earth he was, talking to me on at same level as he would to anyone else.

For the next few years, until I moved to California, I had the privilege of meeting him once almost every year. Each time he would invite me to the institute for lunch. Each time the conversation would last at least three hours if not more. Each time it would range over an incredible set of topics. There were clearly a few among these that we both were interested in; among them were the history of physics, good scientific writing and science as a tool-driven revolution. That last topic was of special interest since he had written a book about it and because chemistry is the preeminent example of a tool-driven revolution. Freeman was especially interested in chemistry, and he confessed it was the only discipline whose details he didn't know much about. He would always ask me to tell him what the latest developments were in the world of chemistry, especially protein chemistry.

Both of us shared our skepticism of computer models. He told me about problems with modeling water and clouds in climate models, I told him about problems with modeling water in proteins. He talked about statistical problems in image processing and related data analysis, I talked about similar problems in model validation in chemistry and drug discovery. Climate change was a topic that we sometimes discussed, but contrary to his portrayal in the media, it wasn't one he was very much interested in at all. I know that his skepticism about climate change will be discussed as part of his legacy, but for me it's a dead letter. I never once remember him denying or arguing the basic facts of climate; his objection was to the exaggerated claims, the intense politicization of the topic and the demonizing of those with dissenting opinions even when these opinions mirrored the basic facts but differed in the details. He questioned not the facts but the exact nature of the consequences, and he thought we simply don't know enough to understand the net balance of pros and cons and some humility should therefore be in order. Sadly the reaction his opinions drew from the public only reinforced his beliefs.

Even beyond his versatile mind and diverse interests, Freeman's overriding interest was always in people and this contributed to the kindness and generosity he always showed. I would say that as much as people have praised his brilliant contributions to science, the words "wise", "kind" and "generous" are the ones that have shown up the most in all the internet tributes to Freeman that I have seen. Science and people were certainly the two main themes that we discussed. This human warmth was reflected in his own family: six children and sixteen children, all of whom are accomplished and doing well. His son George who is an especially accomplished thinker and writer sent some of us a picture of Freeman blowing out candles on his 90th birthday celebration, surrounded by doting children and grandchildren. I would discuss my own family with him: I wrote to him when my beloved father very suddenly died and spoke of my father's overwhelming hunger for knowledge, and he told me how he had read William Prescott's account of the conquest of Mexico to his mother when she was old and unable to read and thought that the writing was so vivid that he was convinced Prescott was there. He recollected his visit to Tasmania where he had been to the densest forest he had seen in his life; I sent him some photos from my own trip to Tasmania when I visited my sister. For Freeman, as important as science was, people were the most important, and the overriding feeling he projected was one of optimism, always convinced that the combination of human decency and technology would make life better for everyone.

After I moved to California I continued our email correspondence. I sent him several posts I had written about a variety of scientific topics and he was always appreciative and had interesting things to say in response. The dozens of emails I am looking at now showcase the same wide range of topics that we discussed in person: physicist Patrick Blackett, family, Oppenheimer, religion, artificial intelligence, Hans Bethe, nuclear energy, black holes, more chemistry and more poetry. It's amusing to see how the trail of our emails roughly correlates with the different companies I worked at during the last decade and the kinds of research I did and how Freeman was always interested in knowing more; DNA-encoded libraries at my first company, protein chemistry at my second, more protein chemistry at my third and automated chemistry and robotics at my current one.

Freeman always had a nice, dry sense of humor delivered with incomparable British understatement, once comparing overzealous climate change activists to Tea Party Republicans and another time telling me how quietly reading a book when he was visiting his daughter in San Diego felt like Samuel Butler's memorable sojourn in rural New Zealand, described so well by George Dyson in his book "Darwin Among the Machines". But it was all in good fun. I loved gifting him books on his birthday: among the ones that he told me he enjoyed were Andrea Wulf's excellent biography of Alexander Humboldt, Peter Conradi's biography of poet and solider Frank Thompson, Lynn Eden's "Whole World on Fire" on how nuclear weapons experts exaggerated their need for more weapons by minimizing the effects of fire, and Leroy Hood's autobiography. Among the books he recommended to me and which I enjoyed were Clara Claiborne Park's "The Siege" about raising a child with autism, Albert Hirschman's "Exit, Voice, Loyalty", about individual choices in challenging organizational environments, and Hans Nossack's "The End", about the bombing of Hamburg. There were many others I will value.

The last time I corresponded with him was barely a month ago. I knew that he would visit his daughter in San Diego each winter, and my work would take me to the city often, so I definitely wanted to see him there. A month or so before my trip I got in touch about dates and he told me that he was not visiting this year because of medical reasons. I had an ominous feeling, but he characteristically asked me to send him latest updates on my work and tell him what I thought about software and robotics, which to him were "a bunch of useful tools smothered in public relations hype", a sentiment with which I couldn't agree more. I sent him a long description of the work that I was doing and told him I would love to see him when I am visiting New Jersey later this year. And then yesterday I heard the news. 

Although I feel devastated by the news, I know that Freeman had the kind of long and successful life that most people can only dream of: he made breakthrough contributions to science and technology over a truly vast range of fields, wrote books communicating the wonders of the cosmos to millions of people, raised a doting family including a bevy of grandchildren and traveled around the world, inspiring both extraordinary as well as ordinary people like myself. Although he's the kind of person who it would be convenient to believe is immortal, what more could one ask for from one's life? I was extraordinarily fortunate to know him for as long as I did.

Like most pieces of sad news this one took a day to sink in. This morning when I woke up, after experiencing that familiar, sweet, brief moment when wakefulness has still not found the terrible facts of the world that sleep has mercifully hidden away, it suddenly hit me with a sinking feeling that I’m in a world which doesn’t have Freeman Dyson in it, and I felt profoundly sad. I am terribly sad that he is no longer around and already dearly miss him, but I also despair that the kind of iconoclastic, rebellious, off-the-beaten-path, always hopeful and optimistic thinking he exemplified so well may not be tolerated so much in our society today with its increasing intolerance to dissenting ideas and rash of pessimistic thinking, and this thought makes his life even more precious and his passing consequently much more devastating in my mind. I dearly hope I am wrong, and now it's up to us to carry on Freeman's good work. 

After reflecting a bit this morning I ended up remembering what Freeman always used to say when we were going to meet, well into his nineties - “I look forward to seeing you. Lots to discuss”. So all I can say is please, let’s keep discussing, thinking, exploring. May we all have the enthusiasm and humanity Freeman had for as long as we can, and may we do it the way he always did: with good humor, eloquence and an untiring optimism and belief in the power of technology and individuals to make the world a better place.

Secrets of the Old One

In 1968, James Watson published “The Double Helix”, a personal account of the history of the race to discover the structure of DNA. The book was controversial and bracingly honest, a glimpse into the working style and personalities of great scientists like Francis Crick, Lawrence Bragg, Rosalind Franklin and Linus Pauling, warts and all. The vividness of Watson’s recollections and the sometimes almost minute-by-minute account make his memoirs a unique chronicle in the history of scientific autobiography.

After Watson’s book had been published, the physicist Freeman Dyson once asked him how he could possibly remember so many details about events that had transpired more than a decade ago. Easy, said Watson: he used to write to his family in America from Cambridge and had kept all those letters. Dyson who had been writing letters to his parents from the opposite direction, from America to Cambridge, asked his mother to keep all his letters from 1941 onwards.

The result is “Maker of Patterns”, a roadside view of the remarkable odyssey of one of the finest scientific and literary minds of the twentieth century. Letters are a unique form of communication, preserving the urgency and freshness of the moment without the benefit and bias of hindsight. They recall history as present rather than past. One wonders if the incessant barrage of email will preserve the selective highlights of life that letters once preserved. Dyson’s letter collection was initially titled “The Old One”. The allusion was to a famous letter from Einstein to Max Born in which Einstein noted his dissatisfaction with quantum theory: “Quantum mechanics demands serious attention. But an inner voice tells me that this is not the true Jacob. The theory accomplishes a lot, but it does not bring us closer to the secrets of the Old One. In any case, I am convinced that He does not play dice”.

Publishers sometimes change titles to suit their whim. Perhaps the publisher changed the title here because they thought it was presumptuous to compare Freeman Dyson to God. I would concede that Dyson is not God, but it’s the metaphor that counts; as these letters indicate, he is certainly full of observations and secrets of the universe. The letters contain relatively little science but lots of astute observations on people and places. Where the science does get explained one senses a keen mind taking everything in and reveling in the beauty of ideas.

Dyson’s letters begin in 1941 when he was a seventeen-year-old student in Cambridge and his parents were in London. They talk about mathematics, mountaineering and the state of the Second Word War. Freeman’s father was a renowned composer and conductor and his mother was a successful lawyer and promoter of women’s suffrage. It seemed to everyone that it was a miserable time to be alive. Hitler had just attacked England the year before and the entire country was suffering from bombing. Cambridge was hollowed out and only a few professors and students were left. The advantage of this situation was that you could learn at the feet of the masters, or in Dyson’s case, around the billiard table. The billiard table belonged to Abram Besicovitch, a brilliant and voluble Russian mathematician who was a formative influence on young Dyson; Dyson used to go on long walks with him on which Besicovitch insisted that the young student speak only in Russian. This solidified a lifelong love of the Russian language in Dyson. He used to usually find Besicovitch and Hardy at the billiard table. In the letters he discusses everything with them, from mathematics to politics. He enjoys attending all their lectures: “Dirac is very slow and easy to follow; Pars and Besicovitch a bit quicker, but still comfortable; Hardy goes like an avalanche and it is all I can do to keep up with him. One learns about three times as much from Hardy in an hour as from anyone else; it is a testing business keeping the thread of his arguments.…”. What Dyson does not mention but what he evocatively described in another volume was the image of Hardy huddled up in his rooms with six students sitting around the table and Dyson feeling that he should just go and hug the old man. At one point he’s appointed “staircase marshal, which means I have to look after my staircase, put out bombs and carry out corpses”. Fortunately all he had to do was operate a fire pump.

During the war, Dyson spent his time first studying at Cambridge and then working for Bomber Command on the bombing campaign over Germany. This was a rather dismal experience, a classic case of muddle-headed bureaucracy winning over saving lives. No letters were written during this time since Dyson used to visit his parents once a week, but he has documented this experience well in his wonderful memoir “Disturbing the Universe”. But there was still mathematics to do. There is mention of getting a manuscript of Kurt Gödel’s and of listening to John Maynard Keynes on uncovering Newton’s astonishing secret work on alchemy and religion which cast him in the light of a magician rather than a rational scientist. On Gödel’s manuscript on the continuum hypothesis, “I have been reading the immortal work (it is only sixty pages long) with [Thomas Mann’s] “The Magic Mountain” and find it hard to say which is the better.” After the war ended, Dyson made his way to Münster, Germany, to a meeting between German and British students to rekindle old relationships. He captures the drama of destruction and the resilience of the citizens in this old city; people even organize makeshift classical music performances among the ruins. There is a brief platonic romantic meeting with a girl who quotes Yeats and warns Dyson to “tread softly, for you tread on my dreams”.

Dyson’s journey toward scientific greatness started when he came to America at the recommendation of Geoffrey Taylor, a well-known hydrodynamics expert who had worked on the bomb at Los Alamos. When Dyson asked him what place he should consider for his PhD studies, Taylor unhesitatingly recommended Cornell University, adding that that’s where all the bright people had gone after the war. This statement was not an exaggeration. Cornell boasted a star-studded constellation of physicists including Hans Bethe, Richard Feynman, Robert Wilson and Philip Morrison. Dyson was assigned to Bethe as a PhD advisor. His first impression of Bethe was characteristic: “Bethe is an odd figure, large and clumsy with an exceptionally muddy old pair of shoes. He gives the impression of being clever and friendly but rather a caricature of a professor; he was second in command at Los Alamos, so he must be a first-rate organiser as well.” And indeed he was. Bethe who was one of the greatest scientific minds of the century had a great ability to pitch problems to every student based on their capabilities; Dyson was undoubtedly the best student he had.

Bethe does figure in Dyson’s accounts, but the real attraction is the young Richard Feynman. Feynman had come from Los Alamos, leaving behind memories of the untimely death of a beloved wife. He was trying to put his life and physics back together and had visions of a new physics of particles and fields that he was constructing from scratch. Dyson was taken by this very American scientist from the very beginning. “Feynman is a man for whom I am developing a considerable admiration; he is the brightest of the young theoreticians here and is the first example I have met of that rare species, the native American scientist…His most valuable contribution to physics is as a sustainer of morale; when he bursts into the room with his latest brain wave and proceeds to expound it with lavish sound effects and waving about of the arms, life at least is not dull.” He later understood Feynman’s tempering through tragedy; both because of his wife’s early death and his experience with the bomb, he had matured beyond his years. Another one of Dyson’s heroes was Philip Morrison who not only had large stores of knowledge about virtually any topic under the sun, but also equally large stores of integrity that allowed him to withstand the onslaught of McCarthyism and refuse to rat out his friends.

Dyson quickly impressed the American community of physicist by his facility with advanced mathematics. Bethe thought so highly of him that he recommended him for a fellowship at Princeton’s Institute for Advanced Studies which sported a roster of theoretical physicists and mathematicians that was unequalled anywhere. Robert Oppenheimer had been appointed director and Albert Einstein, Kurt Gödel and John von Neumann were permanent members. Paul Dirac, Niels Bohr and Wolfgang Pauli were frequent visitors. When Dyson arrived at the Institute, it was already populated by a group of brilliant students from America and Europe. One of them stood out – Cecile Morette who was one of the very few female theoretical physicists around. She and Dyson struck up a close friendship that lasted until her death a few years ago. Life at the institute was a curious mixture of idyllic and intense. Dyson found Americans’ commitment to a full workday curious and took advantage of the picturesque countryside: “In the afternoons I have managed to explore the country around here. It is excellent walking country, and I have met numbers of strange new birds, insects, and plants. The weather could not be better, and I hope to continue this form of exercise indefinitely. My young colleagues are unwilling to join me, as they are obsessed with the American idea that you have to work from nine to five even when the work is theoretical physics. To avoid appearing superior, I have to say that it is because of bad eyes that I do not work in the afternoons.”

There was tea in the British tradition, and parties where Oppenheimer charmed everyone with his dazzling range of scientific, literary and culinary knowledge. A memorable occasion was when Morette convinced a shy T. S. Eliot who was visiting to join the group of young scholars. Another memorable episode was when a drunk Adele, Kurt Gödel’s wife, grabbed Dyson and made him dance with her while an awkward Gödel stood around looking miserable. Gödel was a brilliant, strange man who had discovered the incompleteness theorem, one of the most startling and important results in the history of mathematics and logic. He was loath to engage in casual conversation; only Einstein who adored him and who walked home with him every day was his friend. And yet Dyson seems to have visited the Gödels several times and found Kurt friendly.

Dyson’s profile of Oppenheimer is the most penetrating of anyone’s in the volume. He saw Oppenheimer’s self-destructiveness and self-loathing which translated into casual cruelty. As memorably recounted in his memoirs, Dyson had just finished a marathon road trip with Feynman across the American South and Midwest during which he had come up with his most famous contribution to science: a bridging together and reinvention of two competing theories of quantum electrodynamics, the theory of light and matter, by Feynman and Julian Schwinger. The epiphany had come to him during a bus ride from Albuquerque to Chicago, right after he had been out west and painted some evocative pictures of America; the Ozarks with their beautiful mountains and crushing poverty, the slums of Philadelphia, flash floods in Oklahoma, Melvin Calvin doing Nobel Prize-winning experiments on the path of carbon in photosynthesis in Berkeley.

After he came back his job was to convince Oppenheimer. This turned out to be a nasty little uphill battle. The chain-smoking Oppenheimer used to constantly interrupt speakers with derisive remarks, and Dyson captured his defects well: “I have been observing rather carefully his behaviour during seminars. If one is saying, for the benefit of the rest of the audience, things that he knows already, he cannot resist hurrying one on to something else; then when one says things that he doesn’t know or immediately agree with, he breaks in before the point is fully explained with acute and sometimes devastating criticisms, to which it is impossible to reply adequately even when he is wrong. If one watches him, one can see that he is moving around nervously all the time, never stops smoking, and I believe that his impatience is largely beyond his control.” After Dyson had tried several times to explain his synthesis of Feynman and Schwinger’s theories to Oppenheimer, Hans Bethe came down from Cornell and intervened. As Dyson recounts, he told Oppenheimer and the others that they needed to use Dyson and Feynman’s methods if they wanted to avoid talking nonsense. Bethe’s authority combined with Dyson’s accomplishment finally swayed minds. The next day Dyson found a note from Oppenheimer in his mailbox inscribed with a single phrase – “Nolo contendere”, or “I plead no contest”.

From then on Dyson’s star was on the rise. At important meetings his work was praised by Feynman, Oppenheimer and others. Colleagues and even reporters thronged him, and job offers came flying from left and right. Dyson spent two years in Birmingham to complete the requirements of the fellowship that had brought him to America. Then Feynman left Cornell for Caltech and Bethe recommended him for a position at Cornell. Before he was thirty, Dyson had been elected a fellow of the Royal Society and had become a full professor at Cornell. He did important research in particle physics, but – partly encouraged by a devastating critique of his work by Enrico Fermi in Chicago - he also wisely realized that his interests were not in pursuing one line of research for a long time and teaching students. Oppenheimer had already indicated that he would welcome him for a permanent position at Princeton. 

In the meantime, Dyson had fallen in love. Verena Huber was an accomplished mathematician who Dyson had met at the Institute earlier: “I will not make this a long letter, because in these last days my mind has been completely occupied with problems even more incommunicable than those of mathematical physics. In short, I am in love.” He was as taken by her two-year-old daughter Katrin as by Verena. Dyson’s relationship with Katrin marked the beginning of a delightful lifelong affinity for children; he has had six children and sixteen grandchildren. By the time he made his way to Cornell, two of his children on the way – George and Esther. When Oppenheimer invited him to Princeton, the allure of intellectual freedom and job security for himself and his growing family beckoned, and Dyson accepted. Dyson has been a fixture at the institute in Princeton ever since then, although now and then he has expressed some ambiguous feelings about the ivory tower sheen of the place which has marketed itself as, in Oppenheimer's words, "an intellectual hotel".

The next few years saw Dyson ranging far and wide over mathematics, physics and engineering, a trait which has made him one of the most unique and wide-ranging thinkers of his time. He worked in Berkeley on solid-state physics and in La Jolla on a nuclear powered spaceship and a safe reactor. The nuclear powered spaceship was a lifelong dream, and one which briefly possessed Dyson like a spell: “You might as well ask Columbus why he wasted his time discovering America when he could have been improving the methods of Spanish sheep farming.” The project was housed on a bluff with spectacular views of the Pacific in La Jolla, and Dyson vividly recounts excursions to a glider club on the cliff. He made a trip to the Soviet Union which after the death of Stalin wanted to establish better relations with the United States. 

In Berkeley he first met Edward Teller and worked with him closely on the safe nuclear reactor, and unlike many other physicists Dyson and Teller retained a long friendship. Dyson saw Teller’s very human qualities, but also recognized his fundamental flaws: “It is exciting and infuriating to work with Teller. I had often heard about scientists behaving like prima donnas, and now I know what it means. We had yesterday a long meeting at which I disagreed with him, and he was in a filthy temper. Finally he won the argument by threatening to leave the place if we would not do things his way. I did not know whether to laugh or cry, but it was clear that the best thing was to laugh and go along with him. I do not have to take this seriously. But I understand now what a misery he must have been for Oppenheimer at Los Alamos. Oppenheimer could not let him run the whole show his own way. I am glad I am not likely ever to be Teller’s boss.”

The next part of the collection is the most poignant and personal. Dyson’s wife Verena Huber left him for a man, a mathematician named George Kreisel who ironically Dyson had been instrumental in getting invited as a visiting scientist at the institute. At the age of thirty-five, he had now been left to care for two small children. He implored his parents not to pity him and was astonishingly generous toward Verena: “Please do not offer me your sympathy or your pity. I have been happy in this marriage, and I have no regrets now it is over. It has enriched my life in many ways, and this enrichment is permanent. Second, about Verena. You can blame her for what she has done. But I do not. I consider that she has fulfilled her obligation to me, by bearing me two fine children, by caring for all of us through the difficult years when the babies were small and money was short, and by loving me faithfully for seven years. She leaves me now just when our family life is getting to be easy and comfortable, the children soon to be all at school, the finances ample, and a beautiful house to live in. What she has done may be crazy, but it is not irresponsible. I believe that she has earned her freedom, that she is doing the right thing in following her own star wherever it leads.”

He succeeded admirably in taking care of his children and in bearing the blow of a divorce, partly because he got along with children so well and partly because of Imme Jung, a young caretaker and daughter of a country doctor from rural Germany who had come to look after the children even before Verena left Freeman. This was a very fortuitous development; both the children and Freeman became so attached to Imme that Freeman and Imme got married. Gradually she became fondly integrated into Dyson’s community of friends and colleagues and formed a great partnership with Freeman. They remain happily married sixty years later.

The children were meanwhile turning out to be delightful, engaging in the kind of wise and funny conversation that only children’s unfiltered minds can conceive. Dyson doted on them and often recounted these conversations in his letters. “The children go on with their lives as gaily as ever. Breakfast table conversation. George: “I know that first there were only ladies in the world, and then afterwards the men came.” Esther: “But that is all nonsense. Don’t you know that at the beginning there were just two people, Eve and that other guy, what was his name?” Another conversation, showing the difference between the scientific and the practical approach. George: “I can understand how a boat moves along when you push on the oars. You push the water away and so it makes room for the boat to move along.” Esther: “But I can make the boat move along even without understanding it.”

But George turned out to have an independent streak that was perhaps too independent for his own good. As a teenager he started hanging out with the wrong gang, doing drugs and turning into a hippie. Freeman was not willing to toe the boundaries here, and once when George was arrested for illegal possession Freeman refused to bail him out so that he would learn a lesson. After this George became sullen and withdrawn while Esther went off to Harvard as a confident feminist. George finally decided to stake it out on his own, hiking through the Midwestern wilderness and finally making his home in the sublime coastal country of British Columbia, living in a tree for three years, building canoes in his spare time and making friends with the rustic natives who have made that part of the country their home.

The sixties saw an important evolution of Dyson’s life as he moved from pure physics to applied problems, especially problems of war and peace. He had gotten into the fray during the negotiations that led to the limited test ban treaty banning nuclear tests anywhere but underground. During this debate Dyson was pitted between his old friend Hans Bethe and his new friend Edward Teller, but his friendship with both men escaped unscathed. He was elected to the chairmanship of the Federation of American Scientists that was involved in important issues related to national policy. He became a member of JASON, a crack team of scientists advising the US government on defense problems. And he also joined the Arms Control and Disarmament Agency, an organization that was formed under President Kennedy’s authority to study disarmament. Dyson found himself working in Washington DC during the early part of the decade.

It was as if fate had placed him here for a historic event. It just so happened that he was giving a testimony to a Senate committee on August 28, 1963. When he came out of the Capitol he saw a large crowd of people marching to the Washington Mall. Martin Luther King was about to give one of the greatest speeches in history. Dyson stood only a few feet away from him and witnessed history in the making: “I would like to write to you about today’s events while they are fresh in my mind… The finest of [the speakers] was Martin Luther King, who talks like an Old Testament prophet. He held the whole 250,000 spellbound with his biblical oratory. I felt I would be ready to go to jail for him anytime. I think this whole affair has been enormously successful. All these 250,000 people behaved with perfect good temper and discipline all day long. And they have made it unmistakeably clear that if their demands are not promptly met, they will return one day in a very different temper. Seeing all this, I found it hard to keep the tears from running out of my eyes.” 

A few weeks after King’s speech, the nuclear test ban treaty was ratified by the Senate. Peace at least on one front, even as it escapes on others as JFK is assassinated. While acknowledging the great tragedy, Dyson’s take on the event is characteristically unexpected and astute: “It is a great pity that Kennedy is dead. But to me the moral shock of his killing was much less than that of the killing of Medgar Evers, the negro who was killed in exactly the same way in Mississippi last summer. Evers was an even braver man than Kennedy and is probably harder to replace.”

The next few letters contain items various and sundry; meetings with various scientists like Yuval Neeman and Abdus Salam, accounts of Dyson’s interactions with friends including Leo Szilard and his wife Gertrude Weiss and with Einstein’s formidable secretary Helen Dukas, the death of Dyson’s father – there is a short but touching letter acknowledging his friendship with so many people and not just his stature as a musician – and organizing a sixtieth birthday event and then, in 1967, a funeral for Oppenheimer. It is clear from the letters that Oppenheimer’s influence on Dyson was considerable, and Dyson clearly understood both his deep flaws but also his fundamental greatness. He poignantly talks about how, just before Oppenheimer’s death, his wife Kitty desperately asked Dyson if he could work with Oppenheimer on a piece of physics to lift his spirits. But Dyson realized that the best thing he could do at that point was to hold Robert’s hand.

Life ebbs and flows. After news from his mother of a suspected colon cancer: “In these days I think of the years when I was close to you and spending many days walking and talking with you, the years we lived in London until I went to America, from 1937 to 1947. I was lucky to have you then to see me through the years of Sturm und Drang, to broaden my mind and share with me your rich knowledge of people. I remember reading aloud with you Sons and Lovers by Lawrence, knowing that you and I were a little like Lawrence and his mother, and that this perfect intellectual companionship which we had together could not last forever.” Fortunately the cancer turned out to be curable and Dyson’s mother lived for seven more years. And whenever the news turned grim, mathematics and the excellence of the life it brings always provided succor: “Today I discovered a little theorem which gave me some intense moments of pleasure. It is beautiful and fell into my hand like a jewel from the sky.”

In February 1970, Dyson had his first impressions of a brilliant young physicist from Cambridge who had been struck with an incurable malady. He recognized Stephen Hawking’s greatness even then: “I was taking care of Stephen Hawking, a young English astrophysicist who came here for a six-day visit. I had never got to know him till this week. Stephen is a brilliant young man who is now dying in the advanced stages of a paralytic nerve disease. He got the disease when he was twenty-one and he is now twenty-eight, so his whole professional life has been lived under sentence of death. In the last few years he has produced a succession of brilliant papers on general relativity… These days while Stephen was here, I was in a state of acute depression thinking about him, except for the hours when I was actually with him. As soon as you are with him, you cannot feel miserable, he radiates such a feeling of strength and good humour.”

The early 70s saw Dyson as a veteran scientist, advisor and thinker, sagely advising younger members of the institute in Princeton. He saw himself as a ‘psychiatric nurse’, taking care of young minds who were facing anxiety or depression because of the immense pressure to perform and produce groundbreaking science in their twenties. He recounts two stories, one of which is strange and the other harrowing. The strange story is about a historian of physics named Jagdish Mehra who was accused of stealing and then returning a letter from Einstein without the permission of Einstein’s ferociously loyal secretary Helen Dukas. Mehra later became a distinguished biographer of Feynman, Schwinger and other famous physicists. The harrowing incident was about a Japanese visiting student who committed suicide. Dyson who felt a measure of guilt in not perhaps being attuned to the signs decided to accompany his distraught wife back to Japan, and things got a bit difficult in the air when she loudly started accusing Dyson of murdering her husband and wishing death on his family. These accounts of Dyson’s experience as a psychiatric nurse attests to the enormous pressures that young scientists face at elite institutions.

The late 70s conclude the letter collection. They mark a transition period in Dyson’s life, marked by two events. The first was the death of his mother at age ninety-four. Dyson wrote a moving letter to his sister Alice, imagining how his mother’s sharply observant spirit would be watching over all of them and making sure they stayed on the right track. The second event was a trip to British Columbia to mend the rift with his son George. In Vancouver the Dysons were joined by Ken Brower, a writer who would later write an evocative book called “The Starship and the Canoe” about the father-son relationship. Interspersed with these experiences are meetings with Carl Sagan and Edward Wilson and a citizens’ meeting in Princeton debating a potential ban on recombinant DNA research at Princeton University. The meeting showed how important it is to involve ordinary townsfolk in decisions affecting public policy, and how intelligent ordinary townsfolk are in enabling such decisions.

On the Vancouver coast Freeman encounters whale worshippers whose “love for the animals has the passionate purity of a religious experience”. He feels the primitive harmony of whale song in the infinite silence of the night, observes George building kayaks and sails with him and meets George’s friends who are all perfectly tuned to the rhythms of nature. About two friends who taught George canoe building, one of them crippled, who walk into the rain holding a baby in their arms, “It was pitch dark when Jim and Allison left. I watched them walk slowly down the beach to the boat, in the dark and pouring rain, Jim on his crutches, Allison carrying the baby in her arms. It was like the last act of King Lear, when the crazy old king and his faithful daughter Cordelia are led away to their doom.” Fortunately, Dyson’s view of Jim turned out to be wrong. He patched up his injuries and still spends his time patching up boats. There is a metaphor for the future here somewhere.

Even though the letter collection concludes in 1978, Dyson continued to be immensely valued as a scientist, writer and thinker from the 80s all the way up to the present. As of 2018, at age ninety-four, the Old One continues to speak and write on a variety of topics and continues to be nurtured by Imme, his six children and sixteen grandchildren. George and Esther are leading thinkers, writers and activists themselves, and all the other children lead productive lives as citizens, spouses and parents. He has said on multiple occasions that family, friends and work are the most important things in his life, in that order, and the letters reflect these priorities; I would wager that the word "friend" appears more often in this volume than any other. Since the nineties, when email replaced letters as the chief mode of communication, Dyson has carried out an extended correspondence with friends all around the world. For eight years, both virtually and in person, I have been honored to be one of them.

Along with this volume, two other books by or about Dyson deserve to be read. One of these is his autobiography, “Disturbing the Universe”, which remains the most eloquent, literary and passionate testament by a scientist concerned with human problems that I have read. “Disturbing the Universe” was written in 1979, and it marked Dyson’s transition from being mainly a scientist to being mainly a writer. The memories in that volume complement or overlap the ones in this, and it also contains interesting thoughts on fascinating topics that Dyson didn’t really discuss with his parents; nuclear power, genetic engineering, extraterrestrial life. The second volume is “Dear Professor Dyson” which recounts more than twenty years of correspondence that Dyson has carried out – first through letters and then through email – with undergraduate students at Southern Nazarene University. Those letters also range over a bigger variety of topics and cover important matters like the ethics of defense and the relationship between science and religion.


Freeman Dyson has lived an extraordinary life through momentous times, populated with extraordinary characters and remarkable ideas. The letters in this collection tell us how, and Dyson’s life as described in them is perhaps best captured by something he said a long time ago: “We are human beings first and scientists second, because knowledge implies responsibility."

This is my latest monthly column for the website 3 Quarks Daily.