The two men were at different stages of their careers. Wittgenstein was fifty-two and compiling notes for what would be posthumously the second of his two most influential works, Philosophical Investigations. Dyson was twenty-three and a student. Although he was angling to be a physicist, he was still submitting papers to mathematical journals.
The two saw each other often on the stairs but had little to say to each other. Neither enjoyed dining at the college’s high table, and both usually cooked food alone in their rooms. Dyson could detect the smell of Wittgenstein’s fish.
One day Wittgenstein invited Dyson in for a chat. Dyson was offered the one seat in the room, a low-lying canvas deck chair that left him nearly horizontal and close to the floor, while the older man remained standing over him. Trying to break the awkward silence, Dyson asked Wittgenstein if he still believed the ideas in Tractatus. This was the earlier of Wittgenstein’s major works, a booklet in which he had attempted to build a systematic accounting of logical propositions about the world.
Wittgenstein took offense at Dyson’s question. He began sarcastically badgering Dyson, who eventually fled. Dyson’s judgment issued many years later—and he seldom speaks so decidedly about people—is that Wittgenstein was a charlatan.9
SIXTY SECONDS
Dyson was restless. Where should he go next? London, one of the premier cities of the world, did not suit him. Besides, he wanted to get away from his parents. Cambridge, one of the great universities by any measure, didn’t have the right people for him to talk to. He had friends but not enough physics friends. Cavendish Lab, famous for a century of first-rate physics, would soon be famous for other things—molecular biology and radio astronomy.
Dyson felt he was coming into physics at a propitious time. A student friend of his admitted that to avoid controversies growing up around the quantum explanation of reality he was switching from physics to mathematics. Dyson laughed, since he was switching in the opposite direction precisely in order to embrace the controversies. The greater the challenge, the greater the opportunity to do original work. Dyson wanted to be at the frontier.
To do that he needed to leave England. Initially he had hoped to get a job in the Soviet Union working for one of the great scientists there, such as Lev Landau or Pytor Kapitsa.10 But travel restrictions made this impossible. So he resolved to go to the United States.
He approached Sir Geoffrey Taylor, a man he hardly knew, and asked for advice. Taylor was then a scientist at the Cavendish Laboratory. An expert in blast waves, he had worked at the bomb factory in Los Alamos during the war and therefore knew a lot of American physicists. Considering the kind of work Dyson had in mind, Taylor estimated that Cornell University was the place to be and Hans Bethe was the man to work for. Dyson’s encounter with Taylor lasted about sixty seconds but it was to change everything.11
Dyson knew little of Cornell or Bethe but he took Taylor’s advice anyway and applied for a position at the school and for a fellowship that would support him. Sir Geoffrey did more than render advice. He gave material support. His subsequent letter to Bethe must rank as one of the most succinct and effective, if inflated, graduate school recommendations of all time. After a line or two of formality, the actual encomium is delivered in the space of a single sentence. No more than this was necessary: “Although he is only 23,” wrote Taylor, “he is in my view the best mathematician in England.”12
To clinch the decision, Dyson hopped on a motorcycle and drove in the rain to visit a friend of Bethe’s, Rudolf Peierls, a professor at the University of Birmingham.13 Peierls concurred that Cornell was the place for Dyson to be. Expecting the match to come off, Peierls wrote to Bethe asking him if he would please take good care of Mr. Dyson.14
Before going off to America, the wealthiest place on earth, Dyson visited one of the most devastated places on earth, war-torn Germany. Taking part in a program that was supposed to help bring some kind of normalcy back to German citizens, Dyson spent the summer in the city of Münster. What impressed him most that summer were the lack of food (he was hungry all the time), the mountains of rubble left from the bombings (his bombings), and the habit of the residents to make music together.15 They brought forth battered instruments and coalesced into an impromptu orchestra. Beethoven among the ruins. Dyson was heartened by this.
He was also intrigued by a number of young women in the town, especially Hilde Jacobs. But at the end of the summer she stayed where she was, while he went far away.16
3. Ecumenical Councils
Dyson as Seminarian
(1947–1948)
Like Odysseus, Dyson had been entangled in a great war and afterward arrived safely in Ithaca. After side trips by motorcycle from Cambridge to Birmingham and to Germany by train and ship, he proceeded via the Queen Mary to America, past the Statue of Liberty. He was shown around New York City by Hermann Bondi and then went by train from New York Bay up to Cayuga Lake. In September 1947 Dyson came to Cornell University in the middle of a heat wave. Oddly it was cold indoors owing to the extravagant laying on of air conditioning, still a novelty. The departmental secretary wore a sweater.1
The boots, the muddy boots, were the first thing Dyson noticed in Hans Bethe’s office. Muddy boots symbolized something new. Famous professors in Britain did not, in Dyson’s experience, hike about with their students and then have lunch with them, sometimes four or six at a time.2 Dyson, long accustomed to learning alone, would now be part of a community. He was a seminarian at a physics monastery.
WHICH DYSON?
Most young seminarians are anonymous, but not Dyson. Some people at Cornell, the mathematicians anyway, had heard of a Dyson. Rumor had it that he was one of the best mathematicians in England. The one in front of them was another Dyson, a physics student just starting out. Was this Dyson related to that Dyson? The mathematician Dyson gave an impressive talk about number theory. The other Dyson, the one coming to study at Cornell, didn’t know much physics, or so they said.
This and that Dyson were the same man. At first his fellow graduate students didn’t know what to make of him. He liked taking his ease, reading the newspaper for hours with his feet up on the table, going for a walk, or just staring dreamily out the window.3 Maybe that’s the way mathematicians were. If so, why was he enrolling in physics?
He was on the frail side. And that aquiline face, with deep-set staring eyes, pointy ears. The bemused smile was a bit odd. Was he concentrating on an idea or was he smirking? He was from London, so maybe he wouldn’t like it in Ithaca, which is only a small town perched on the southern fringe of one of New York state’s glacier-carved Finger Lakes. “Ithaca is gorges,” the tourist office says, but Freeman Dyson had come not for the natural beauty of the place but for the people.
He wanted to talk to people. The most stupendous enterprise in all of physics, maybe all of science, over the past quarter century, had been the creation of an atomic bomb at Los Alamos. And here at Cornell was assembled a considerable cohort of Manhattan Project veterans that had forged the gadget that spawned the nuclear age.
Hans Bethe, the most distinguished, had been head of the bomb design theoretical group. Born in Germany, he had made his name, and much later would win the Nobel Prize, for his explanation of sunshine. Having invented big parts of nuclear physics along the way, Bethe declared that the light we see from the sun and other stars is produced in a series of reactions that fuse hydrogen nuclei into larger nuclei amid the crushing conditions at the heart of our local star.
Philip Morrison had been the baby-sitter of the atomic age. He accompanied the plutonium bomb, the very first nuclear bomb, out to the Trinity test site in New Mexico in July 1945. A month after that he rode out to the West Pacific, shepherding the components destined for the Hiroshima bomb. Weeks later he was one of the first Allied scientists to view the effects of that bomb up close when he strode through what was left of the city. Morrison became a distinguished astrophysicist and popularizer of science. Possessed of a talent for evocat
ive prose, he wrote elegant book reviews in Scientific American for decades on a wide spectrum of topics.
Robert R. Wilson, another of the Cornell professors, had been head of the experimental division at Los Alamos. He had grown up on a ranch in Wyoming, was familiar with horses and guns, and had an open disposition. When Dyson arrived, Wilson was then building an electron accelerator at Cornell. Twenty years later Wilson was appointed to construct an immense proton accelerator in Illinois. This was the time of the Vietnam War and Wilson was asked during congressional hearings by a senator what this expensive machine was likely to contribute to the national defense. Nothing, Wilson responded, except that it would help to make America a nation worth defending. The lab was approved. Later called the Fermi National Accelerator Laboratory after Enrico Fermi, it was built within budget, ahead of schedule, and mustered twice the beam energy that was called for in the original design. This machine was for many years the most powerful atom smasher in the world and would be the site for several major physics findings.
These three men were fun to be with and crackled with ideas. A fourth Cornell professor, however, outdid even Wilson and Morrison as a bon vivant. Richard Feynman is now recognized as a brilliant scientist, explainer, and teller of homespun anecdotes. He had been a comparative youngster at the Los Alamos bomb project, where he was in charge of computing. He’d been recruited for the work by Robert Wilson. Even then, in that galaxy of world-class scientists, Feynman was conspicuous for his bright wit, friendliness, and enormous promise. Dyson first talked with Feynman on a car trip to a science meeting in Rochester that fall of 1947.4 Dyson didn’t enroll in any course with Feynman. Instead he got something better—a monthlong conversation with Feynman, conducted mostly at chalkboards.
Dyson was lucky. Not only had he not died during the war, but he was entering into his studies just as the laws of quantum science were about to be rewritten. Indeed, he would be one of the rewriters. But he did not yet have a career. He was mostly self-taught in physics. His knowledge was all top-end: he had a sound grasp of quantum field theory and relativity but knew less about the fundamentals imparted to most beginning students, a deficiency soon to be remedied.
Now he wanted to satisfy others with his work. They were looking over his shoulder. He enjoyed their attention, and he was up to their expectations. Furthermore, his life was, still at this point, rather tidy: no wife, no debts, no debilitating habits. Seminarians must harden their discipline. “For the first time in my life,” he said in a letter to his parents, “I can think about physics continually and without effort, and I want to confirm the habit before letting it drop.”5 You can almost hear his mother, remembering her teenage son’s obsession with his calculus textbook, admonish Freeman to get out into the sunlight.
Dyson liked life in his adopted country. Growing up, he had listened to the radio broadcasts of Alistair Cooke (much later the genial host of the PBS program Masterpiece Theatre), who provided Britons with a regular report on life in America much as Edward R. Murrow’s wartime broadcasts from London vividly portrayed British life for Americans. Dyson found America to be pretty much as Cooke described.6
Dyson had to register in the fall like any other incoming graduate student. He took a quantum course from Bethe, a course in experimental nuclear physics from Wilson, a course on solid state physics, and one on general laboratory techniques. He wasn’t very good at the latter. Performing a routine reenactment of the Millikan oil drop experiment, the famous exercise that established the electrical charge of the electron, Dyson touched the wrong outlet, was zapped by electricity, and left on his back.7 He wasn’t seriously hurt, but this little mishap made him think hard about the reality of electrons.8 His experimental career ended on that floor. He would stick to theoretical work.
THE COUNCILS OF SOLVAY
We oughtn’t to call science a religion. Science accepts assertions on observational grounds not as points of faith. Nevertheless, an air of religiosity lingers among the heirs of Isaac Newton. For example, in their occasionally near-monastic habits and their reverence for laws, their love of classifications, their insistence on consistency, and their rigorous, almost ritual, observance of procedure, scientists at work can resemble a priesthood. For both scientists and clerics the hieratic urge shows itself in a high degree of assurance and a disdain for trivial pursuits. Both desire to encompass the cosmos. All layers of existence, sacred or secular, must be accounted for.
For both the early Christian church and twentieth-century physics, historically significant propositions concerning orthodoxy had to be clarified and a new consensus erected in solemn conclaves of bishops. In the year 325, for instance, several hundred prelates met in Nicaea, located in what is now Turkey, to settle the issue of consubstantiality: God the Father and Christ the Son, it was decided, were of one essence. In 359 another council, this one in Constantinople, pronounced the grand unified theory of the Trinity: Father, Son, and Holy Spirit were all equally aspects of a single underlying godliness.
Like the church in the fourth century, so physics in the twentieth century would sort through some of the most fundamental aspects of existence: space, time, causality, measurement, and the apparent dual nature of matter as particle and field.
Seminarians learn by watching their elders and by studying the great debates of the past. To see what Bethe and Feynman, and then Dyson, were laboring over, it will be useful to recapitulate the quantum age by looking over the deliberations at several important conferences. The first of these meetings—the equivalent of those conclaves in Nicaea or Constantinople—took place in Brussels. It was started by a businessman named Ernest Solvay.
Solvay 1911. This first big gathering of twentieth-century scientific celebrities profiled a series of startling but baffling advances accumulated over the previous fifteen years or so, starting with the observation of several emanations coming from atoms. Atoms were supposed to be a-tomos, “uncuttable.” They weren’t supposed to have moving parts. And yet look at what atoms were spewing forth: Konrad Roentgen found X-rays (1895), Henri Becquerel observed radioactivity (1896), and J. J. Thomson discovered the electron (1897). Ernest Rutherford (1911) found that much of the mass of atoms was actually located at a heavy core called the nucleus. So an atom wasn’t so simple after all.
Solvay 1927. Coming right after an intensely revolutionary couple of years of brainwork, this later Solvay meeting showcased the sensational new quantum science. The idea that energy comes only in fixed amounts—the quanta—had at first seemed repellent to many physicists. But a new generation, embracing the quantum energy concept, would soon have success in explaining a variety of phenomena, such as the spectrum of light shining from atoms.
This success, as we have seen, came at a price, since we were asked to surrender several basic notions of reality. In their place came the troubling and wonderful ideas that a particle didn’t fully exist until we detected it and that even then there were limits on how much we could know about the particle’s location and its motion.
It wasn’t much consolation to be told that all these quantum rules, even though valid everywhere, essentially manifested themselves only for happenings at the atomic scale. Were centuries of Western philosophy and scientific probity being thrown out by a coterie of upstarts? Well, yes, but maybe this was good. Like the earlier revolutions begun by Copernicus and Darwin, the quantum upheaval begun by Planck demonstrates that science lurches forward when imaginative people offer disturbing ideas to explain puzzling observations. The bomb throwers making the outrageous quantum assertions—Werner Heisenberg, Wolfgang Pauli, Paul Dirac—were in their twenties. Their audacious efforts were sarcastically referred to as Knaben Physik, physics by boys.
At the 1927 Solvay conference the champion of the forces of probability and indeterminacy was a somewhat older man, Niels Bohr of Copenhagen. The reactionary forces objecting to quantum weirdness were led by Albert Einstein, who, ironically, had introduced some of the original quantum ideas. Einstein argued
that impressive as it might be in explaining the spectra of atoms, the Copenhagen school (named for Bohr’s hometown) of thought, as the consensus quantum outlook came to be known, was surely incomplete. A fuller understanding of quantum phenomena, he insisted, would duly restore the objective and deterministic standards of observations enshrined in science going back to the days of Newton.
Accepting indeterminacy was too much, Einstein argued. Do you mean to say that a radioactive particle inside a nucleus can come flying out whenever it wants, without being kicked, or that an electron can somehow manage to fly through several openings in a screen at the same time? Is the universe really deciding things according to some underlying, unseen spreadsheet of probabilities? “God doesn’t play at dice,” was Einstein’s quip. To which the unflappable Bohr replied, “Albert, stop telling God what to do.”
As the 1930s and 1940s wore on the Copenhagen interpretation of quantum reality became catholic doctrine among physicists. Not because some pope said so but because of its own great success in explaining a variety of phenomena at the level of atoms and molecules. Even the much smaller and more powerful realm of the nucleus was apparently ruled by the catechism of quantum mechanics. The making and deployment of a nuclear bomb, felt on the ground in Hiroshima and Nagasaki and splashed across newspapers around the world, was a graphic and lethal demonstration of quantum knowledge at work.
Dyson was too young to have been a participant at the Solvay meetings or the Manhattan Project. But it was still an exciting time to move from pure mathematics into science. Mathematics was, according to G. H. Hardy, closer to art. Art and mathematics can stand alone. A poem and a geometrical theorem can both last forever. Science is different. It is necessarily provisional. It will always have to be replenished, like layers of skin, when new observations become available. Mathematics and art can be beautiful, said Hardy. They are entertaining. Science, by contrast, is practical. It explains things.
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