CALTECH - Genius: The Life and Science of Richard Feynman - James Gleick

Genius: The Life and Science of Richard Feynman - James Gleick (1993)


The California Institute of Technology had entered the 1920s with an engineering building, a physics building, a chemistry laboratory, an auditorium, and an orange grove on a dusty, underirrigated thirty acres a few minutes east of the thriving civic center of Pasadena, a town of new money in search of monuments. The scent of orange and rose floated from the gardens of porticoed homes often described as mansions, built in a relaxed Spanish and Italianate style that was coming to be thought of as Californian. Walls were a pale stucco, roofs a red tile. “Pasadena is ten miles from Los Angeles as the Rolls-Royces fly,” one commentator said in 1932. “It is one of the prettiest towns in America, and probably the richest.” Albert Einstein wintered there for three years, posing for pictures on a bicycle to the delight of the institute administrators, attending, as Will Rogers said, “every luncheon, every dinner, every movie opening, every marriage and two-thirds of the divorces,” before he finally decided Princeton suited him better. Even as the Depression began to reverse Pasadena’s fortunes, Caltech’s rose on every new tide in science. A new Caltech laboratory polished the giant lens for the great telescope under way at Palomar Mountain. Caltech made itself the American center of systematic earthquake science; one of its young graduates, Charles Richter, devised the ubiquitous measurement scale that carries his name. The school moved quickly into aeronautic science, and a group of enthusiastic amateurs firing off rockets in the hills about the Rose Bowl became, by 1944, the Jet Propulsion Laboratory. Foundations and industrialists were eager to look beyond their usual East Coast funding targets. A cornflakes manufacturer paid for a building that became the Kellogg Radiation Laboratory, and its reigning expert, Charles Lauritsen, made it a national center for fundamental nuclear physics. Lauritsen spent much of the thirties investigating the nuclear properties of the light elements—hydrogen and deuterium, helium, lithium, up through carbon and beyond—filling in details of energy levels and spin with a patched-together arsenal of equipment.

He was still working in Kellogg in the winter of 1951, when oracular messages started coming in by ham radio. A blind operator in Brazil would establish a link every week or so with a student at Caltech. Lauritsen would receive terse predictions: Could it be that nitrogen has two levels very close together at the lowest state, not just a single level? He would check these, and often they would prove correct. His Brazilian informant apparently had a theory …

In Chicago, Fermi, too, heard from Feynman—a long “Dear Fermi” letter just before Christmas from the Miramar Palace Hotel in Copacabana. Feynman, following the thread he had picked up in the episode of Case v. Slotnick, was working on meson theory. It was messy—divergences everywhere—but he had reached a hodgepodge of conclusions. “I should like to make some comments at the risk of saying what is obvious to everybody in the U.S.,” he wrote Fermi. Mesons are pseudoscalar … Yukawa’s theory is wrong. He had heard some experimental news via the ham-radio link—“I am not entirely in the dark in Brazil.” He had some predictions that he wanted checked. His approach to these particles, so essential to the binding of the atomic nucleus, centered increasingly on an even more abstract variant of spin: yet another quantum number called isotopic spin. So did Fermi’s approach, as it turned out. Feynman was duplicating some of the Chicago work. In their ways they were trying to take the measure of a theory that resembled quantum electrodynamics yet resisted the lion tamers’ favorite whips, renormalization, perturbation theory. “Don’t believe any calculation in meson theory which uses a Feynman diagram!” Feynman wrote Fermi. Meanwhile, as they pushed more energetically inside the atom, they were watching the breakup of the prewar particle picture. With each new particle, the dream of a manageable number of building blocks faded. In this continually subdividing world, what was truly elementary?

What was made of what? “Principles,” Feynman had written in the tiny address book he carried with him. “You can’t say A is made of B or vice versa. All mass is interaction.” That did not solve the problem, though. Cloud chamber photographs showed new kinds of forks and kinks in the trajectories—new mesons, it seemed, before anyone had understood the old. Fermi set the tone for the coming proliferation of particles with a declaration in the Physical Review.

In recent years several new particles have been discovered which are currently assumed to be “elementary,” that is, essentially structureless. The probability that all such particles should be really elementary becomes less and less as their number increases.

It is by no means certain that nucleons, mesons, electrons, neutrinos are all elementary particles… .

Feynman had made his escape shortly after arriving in Pasadena. He accepted Caltech’s offer of an immediate sabbatical year and fled to the most exotic place he could find. The State Department subsidized his salary. For the first time since Far Rockaway he could spend days at the beach, where he looked over the crowds in sandals and bathing suits and gazed at the endless waves and sky. He had never before seen a beach where mountains loomed just behind. At night the Serra da Carioca were black humps in the moonlight. Royal palms like dressed-up telephone poles—taller by far than the palms of Pasadena—lined the coast and the broad avenues of Rio. Feynman went down to the sea for inspiration. Fermi teased him: “I wish I could also refresh my ideas by swimming off Copacabana.” Feynman liked the idea of helping build a new seat of physics at the Centro Brasiliero de Pesquisas Físicas. Fifteen years before, physics had hardly existed in Brazil or elsewhere in South America. A few lesser German and Italian physicists had grafted branches in the middle 1930s, and within a decade their students’ students were creating new facilities with the support of industry and government agencies.

Feynman taught basic electromagnetism to students at the University of Brazil in Rio, who disappointed him by meekly refusing to ask questions. Their style seemed rote and hidebound after freewheeling Americans. European influence had dominated the construction of a curriculum. The nascent graduate programs did not have the luxury of a liberal mix of confident instructors. Memorization replaced understanding, or so it seemed to Feynman, and he began to proselytize the Brazilian educational establishment. Students learned names and abstract formulations, he said. Brazilian students could recite Brewster’s Law: “Light impinging on a material of index n is 100 percent polarized with the electric field perpendicular to the plane of incidence if the tangent …” But when he asked what would happen if they looked out at the sunlight reflecting off the bay and held up a piece of polarized film and turned the film this way and that, he got blank stares. They could define “triboluminescence”—light emitted by crystals under mechanical pressure—and it made Feynman wish the professors would just send them into a dark room with a pair of pliers and a sugar cube or a Life Saver to see the faint blue flash, as he had when he was a child. “Have you got science? No! You have only told what a word means in terms of other words. You haven’t told them anything about nature—what crystals produce light when you crush them, why they produce light… .” An examination question would read, “What are the four types of telescope?” (Newtonian, Cassegrainian, …) Students could answer, and yet, Feynman said, the real telescope was lost: the instrument that helped begin the scientific revolution, that showed humanity the humbling vastness of the stars.

Words about words: Feynman despised this kind of knowledge more intently than ever, and when he returned to the United States he found out again how much it was a part of American education, a mind-set showing itself not just in the habits of students but in quiz shows, popular what-should-you-know books, and textbook design. He wanted everyone to share his strenuous approach to knowledge. He would sit idly at a café table and cock his ear to listen to the sound sugar made as it struck the surface of his iced tea, something between a hiss and a rustle, and his temper would flare if anyone asked what the phenomenon was called—even if someone merely asked for an explanation. He respected only the not-knowing, first-principles approach: try sugar in water, try sugar in warm tea, try tea already saturated with sugar, try salt … see when the whoosh becomes a fizz. Trial and error, discovery, free inquiry.

He resented more than just the hollowness of standardized knowledge. Rote learning drained away all that he valued in science: the inventive soul, the habit of seeking better ways to do anything. His kind of knowledge—knowledge by doing—“gives a feeling of stability and reality about the world,” he said, “and drives out many fears and superstitions.” He was thinking now about what science meant and what knowledge meant. He told the Brazilians:

Science is a way to teach how something gets to be known, what is not known, to what extent things are known (for nothing is known absolutely), how to handle doubt and uncertainty, what the rules of evidence are, how to think about things so that judgments can be made, how to distinguish truth from fraud, and from show.

Telescopes, Newtonian or Cassegrainian, had flaws and limitations to go with their wondrous history. An effective scientist—even a theorist—needed to know about both.

Faker from Copacabana

Feynman told people that he had been born tone-deaf and that he disliked most music, despite the conventional observation that mathematical and musical aptitude run side by side. Classical music—music in the European tradition—he found not just dull but positively unpleasant. Above all it was the experience of listening that he could not stand.

Those who worked near him over the years knew nevertheless about the toneless music that seemed constantly to well up through his nerve endings, that clattered and pounded through their shared office walls. He drummed unconsciously as he calculated, and he drummed to attract a crowd at parties. Philip Morrison, who shared an office with him at Cornell, would say half seriously that Feynman was drawn to drumming because it was a noisy, staccato activity, because he had long fingers, and because it went with being a magician. But Morrison also noticed how freakish Western classical music had become by the twentieth century in one respect: of all the world’s musical traditions, the West’s had most decisively cast out improvisation. In Bach’s era mastery of the keyboard still meant combining composer, performer, and improviser in one person. Even a century later, performers felt free to experiment with improvising cadenzas mid-concerto, and Franz Liszt toward the end of the nineteenth century gave concertgoers a taste of the athletic thrill of hearing music made up on the spot as fast as a pianist could play, hearing impromptu variations and embellishments along with the false steps and blind alleys from which the performer-composer would have to extricate himself like Houdini. Improvisation meant audible risk and wrong notes. In modern practice an orchestra or string quartet that plays a half-dozen wrong notes in an hour is judged incompetent.

Having resisted the MIT version of Western culture for engineers, having rejected the liberal arts version of culture at Cornell, Feynman finally began his own process of acculturation in Brazil. Travel for most Americans, physicists included, still began with the capitals of Europe, where Feynman never ventured until he was thirty-two and a conference brought him to Paris. In the streets of Rio he discovered a taste for the Third World and especially for the music, the slang, and the art that was not codified in books or taught in school—at least not American schools. For the rest of his life he preferred traveling to Latin American and Asia. He soon became one of the first American physicists to tour Japan and there, too, headed quickly for the countryside.

In Rio Feynman found a living musical tradition—rhythm-centered, improvisational, and hotly dynamic. The word samba was nowhere to be found in his Encyclopaedia Britannica, but the sound rattled through his windows high above the beach, all brass, bells, and percussion. Brazilian samba was an African-Latin slum-and-ballroom hybrid, played in the streets and nightclubs by members of clubs facetiously called “schools.” Feynman became a sambista. He joined a local school, Os Farçantes de Copacabana, or, roughly, the Copacabana Burlesquers—though Feynman preferred to translate farçantes as “fakers.” There were trumpets and ukuleles, rasps and shakers, snare drums and bass drums. He tried the pandeiro, a tambourine that was played with the precision and variety of a drum, and he settled on the frigideira, a metal plate that sent a light, fast tinkle in and around the main samba rhythms, the mood shifting from explosive abstract jazz to shameless pop schmaltz. At first he had trouble mastering the fluid wrist torques of the local players, but eventually he showed enough competence to win assignments on paid private jobs. He thought he played with a foreign accent that the other musicians found esoteric and charming. He played in beach contests and impromptu traffic-stopping street parades. The climactic event in the yearly samba calendar was Rio’s carneval in February, the raucous flesh-celebrating festival that fills the nighttime streets with Cariocas half naked or in costume. In the 1952 carneval, amid the crepe paper and outsized jewelry, with revelers hanging from streetcars whose bells regurgitated the samba beat, a photographer for a local version of Paris Match snapped a carousing American physicist dressed as Mephistopheles.

As hard as he threw himself into life in Rio, he was lonely there. His ham-radio link was not enough to keep in touch with the fast-changing edge of postwar physics. He heard from hardly anyone, not even Bethe. That winter he drank heavily—enough to frighten himself one day into swearing off alcohol one more time, for good—and picked up women on the beach or in nightclubs. He haunted the Miramar Hotel’s outdoor patio bar, where he socialized with an ever-changing group of expatriate Americans and Englishmen. He took out Pan American stewardesses, who stayed on the Miramar’s fourth floor between flights. And in an act of rash abandon he proposed marriage, by mail, to a woman he had dated at Cornell.

Alas, the Love of Women!

The popular anthropologist Margaret Mead had recently reported what so many popular magazines were already noticing: that the courtship rituals of American culture were in ferment. Mead examined billboard advertisements and motion-picture plots and declared, “The old certainties of the past are gone, and everywhere there are signs of an attempt to build a new tradition …”

In every pair of lovers the two are likely to find themselves wondering what the next steps are in a ballet between the sexes that no longer follows traditional lines, a ballet in which each couple must make up their steps as they go along. When he is insistent, should she yield, and how much? When she is demanding, should he resist, and how firmly?

Sometimes Feynman looked at his own mating habits with a similar detachment. Since Arline’s death he had pursued women with a single-mindedness that violated most of the public, if not the private, scruples associated with the sexual ballet. He dated undergraduates, paid prostitutes in whorehouses, taught himself (as he saw it) how to beat bar girls at their own game, and slept with the young wives of several of his friends among the physics graduate students. He told colleagues that he had worked out a kind of all’s-fair approach to sexual morality and argued that he was using women as they sought to use him. Love seemed mostly a myth—a species of self-delusion, or rationalization, or a gambit employed by women in search of husbands. What he had felt with Arline he seemed to have placed on a shelf out of the way.

Women told him that they loved him for his mind, for his looks, for the way he danced, for the way he did try to listen to them and understand them. They loved the company of his intellectual friends. They understood that work came first with him, and they loved that about him, although Rose McSherry, the New Mexican woman he courted intensely by mail at the height of his work on quantum electrodynamics, resented it when he returned from the Pocono conference and wrote her that work would always be his “first love.” She would never marry a man to slave for him, she said. Sometimes she worried that he thought of women as mere recreation. She wished she could feel that he did his work because of her and for her. So many women wanted to be his muse.

The changing rules caught Feynman’s lovers in a bind. The language of illicit sex relied on awkward euphemisms and old-fashioned labels, spooning and jilting, heels and tramps, defining their roles and leaving them at a disadvantage. In his first summer at Cornell, a woman he had met in Schenectady let him know as indirectly as possible that she was pregnant and then that the pregnancy was over. “I have been quite indisposed—something unusual for me—but I think you have undoubtedly guessed the reason.” As she wrote, she knew that he was renewing a fling with his “Rose of Sharon.” She knew she was supposed to hate him, but she preferred not to think of men as “heels.” She assured him that she was not “in love.”

I almost envy you the wonderful and supreme happiness that you must have enjoyed before your wife passed away. Such happiness comes to so few people—I wonder—can it happen twice in one’s lifetime?

She did offer him a warning, saying sarcastically that she was sure he would recognize a bit of Byron:

Alas, the love of women! it is known

To be a lovely and a fearful thing; …

And their revenge is as the tiger’s spring,

Deadly, and quick, and crushing; yet, as real

Torture is theirs—what they inflict they feel.

They are right; for man, to man so oft unjust,

Is always so to women …

In a postscript, she corrected his spelling of her name.

Women were expected to contend in the work force—another trend accelerated by the war—but they also stood in the centerpiece of a cozy domestic vision of family life. The professions, and particularly the sciences, remained in the rear guard. The new Physics Today summed up the difficulties from the sober perspective of someone who had spent more than a decade teaching physics to undergraduates at Bryn Mawr, where a local ditty asked,

Tell me what it is like to be teaching these girls?

Do you find that they have any brains?

Do they take themselves seriously (may I ask) or do you?

The editors were determined to keep the tone lighthearted. The author argued, not without sympathy, that the single most grievous obstacle to the success of women as physicists was their own “tendency to defer to the superior male.” Meanwhile employers continued to assume that women’s eventual priority would be marriage and children. In the Physical Review women almost never appeared as authors.

In their wholly male world, physicists were even less likely than other American men to look for intellectual partnership in their sexual relationships. Some did, nevertheless. In the European tradition, where the professoriat implied a certain social class and cultural grounding, wives had tended to share their husbands’ class and culture: Hans Bethe married the daughter of a theoretical physicist. In the American social stew, where science had become an upward pathway for children of the immigrant poor, whatever husbands and wives might be assumed to share, it was not necessarily a background in the academy. Feynman, alone anyway in the distant reaches of much of his work, seemed to date only women of obvious beauty, often blondes, sometimes heavily made-up and provocatively dressed—or so it seemed to some of the women he did not date. He hardly seemed interested in professional companionship from the women he chased, try though they might to offer it. “I’m learning more everyday about physics and realizing that there is just reams more to learn,” one of his lovers wrote. “Somehow the field of physics has a fatal fascination for me.” She suspected, though, that he had already moved on to someone else. She and all her successors shared an unforgivable handicap, and some of them guessed it: They were not Arline Greenbaum, Feynman’s Juliet, the one perfect love, the girl who had died before the mundane, domestic, day-today, year-to-year realities of ordinary life could have time to add a tempering color and tone to the romantic ideal.

Every so often Feynman would feel the urge to bring a measure of rationality to his relations with women. He loved to work out the rules, to find the systems. He tired of the susurrus of promises, flattery, cajoling. He hated having to apologize. He turned Arline’s favorite principle to a new purpose: “It seems to me that you go to lots of trouble to be sure the girl doesn’t think ill of you,” he wrote in a note to himself after one emotionally messy encounter.

WHAT DO YOU CARE WHAT SHE THINKS? It is all right to care whether you hurt her or not—just do your best, (if you insist) on trying not to—then if the fact is that you are O.K., don’t bother to try to argue otherwise or try to get her to tell you you are wonderful… . Further, if you are selfish & look only to your physical pleasure—don’t try to convince yourself otherwise—or rather—don’t try to explain it to her or convince her otherwise.

In his favorite bar story he gradually deduces the procedural machinery of a bar: women flirt with the customers, the customers buy them drinks, the women move on. “How is it possible,” he would say, “that an intelligent guy can be such a goddamn fool when he gets into a bar?” He is such a neophyte in a bar, such a naïve outside-the-experience anthropologist, that even his education in how to order a Black and White with water on the side holds interest. He watches as bar girls goad him to buy champagne cocktails. In retaliation he learns a new set of procedures. The main rule is to treat the women with disrespect. It is psychological warfare. “You are worse than a whore,” he tells someone whom he has bought sandwiches and coffee for $1.10. His reward: she sleeps with him and repays him for the sandwiches, too. All’s fair.

Feynman told these very stories to the women he dated. Despite their too-good-to-be-true quality, they were convincing and funny. No one ever caught him in a lie. Like many people who discover that storytelling is a talent—that they can hold an audience, focus a roomful of eyes—he honed his repertoire, never caring whether the crowd included people who had heard a story before. Nor, mostly, did they care. With his stories, his laughter, his dancing, his ability when alone with another person to concentrate his attention absolutely, he was intensely attractive to women. This despite the central coldness he held so close—this noetic Casanova. They suffered, sometimes, enormous pain. A second woman told him euphemistically that she had had an abortion: “The whole thing is horrible, cruel and wretched, and happens about once in two million… . I’m sure you never dreamt that any harm would come of such a sudden urge (shall we say, the ‘shortest part’ of an urge) but as I mentioned before the innocent have to pay, etc. etc.” Later she asked him to forgive the mean things she had said.

They almost always did forgive him. They loved to recite his virtues. A catalog that one woman set down on paper:

1. Handsome (could be)

2. clever (he thinks)

3. tall (very)

4. well dressed (trim)

5. a dancer (From a whore in Mexico City)

6. a drummer (whow!)

7. personality plus (oh boy!)

8. smart (putting it mild)

9. conversation (good)

10. sweet (sometimes)

On professional trips overseas he seduced women so regularly that his hosts knew he expected them to make introductions. In London he would meet Pauline or Betty, in Paris Isabelle or Marina, in Amsterdam Marika or Genny. He would see a woman for days and then file her farewell letter with the others:

My love for you is so great that I’m sure it would have brought us both a wealth of happiness … please always remember, when in the evening of your life … that somewhere in the world there is me and that I love you. For I shall always remember you because you are the only person that I have felt at complete ease and sympathy with.

There were so many attitudes a woman could assume for a short-term love affair. His lovers would warn him jovially not to break too many hearts, or they would wish him luck with all his projects “be they blonde or mathematical—or physical!” They would hint that they might appear on his doorstep—that his “sorcière” might not know the way to the moon and stars but could find the USA—or implore, “concerning your work hurry up to find an atomic broom which could fly from Europe to California in a couple of hours.” They would accuse him of preferring his own company—of a “Narcissus-of-the-mind complex.” They would wonder aloud what home really meant to him—was he not a little lonely, after all?

He was. His friends refused to understand why he finally chose to settle down with Mary Louise Bell of Neodesha, Kansas, who had met him in a Cornell cafeteria and pursued him—they said cattily—all the way to Pasadena and finally accepted his proposal by mail from Rio de Janeiro. They considered her a platinum blonde (“the girl with the cellophane hair” was one unkind nickname that floated behind Feynman’s back) who wore white high heels and tight white shorts to picnics. They thought she was older than he was (the age difference was actually just a few months). Even before they married, they quarreled by mail about how much they should spend on interior furnishings and how he looked in old clothes. She made clear that she did not usually think scientists were much fun. She had studied the history of Mexican art and textiles—that was exotic enough to interest him. While he was in Brazil, she taught courses at Michigan State University in the History of Furniture and Institutional Interiors, mainly to men pursuing careers in hotel or restaurant management. “The pattern is that the girl who teaches this course usually marries one of those characters,” she told him.

They married as soon as he returned from Brazil, in June 1952, and they honeymooned in Mexico and Guatemala, where they ran up and down Mayan pyramids. He made her laugh, but he also frightened her with what she decided was a violent temper. She did not know what to think when, riding down a Mexican highway, she complained that the car’s sun flap was annoying her, and he pulled out a screwdriver and repaired it, with both hands off the wheel. She gave his friends the impression that she did not altogether appreciate him. She wanted him to dress better; they discovered that they could tell whether she was near by looking to see whether he was wearing a necktie. She nagged him, they thought. She liked to tell people that he was not “evolved” to the point of appreciating music and that sometimes she thought she was married to an uneducated man with a Ph.D.

They moved from Feynman’s bungalow apartment near campus to a larger place in Altadena, just across Pasadena’s northern border. She resisted socializing with other physicists. Once he missed a chance to catch Niels Bohr while he was in Pasadena briefly; as he and Mary Lou were sitting down to dinner, she said that she probably should have told him, but someone had invited them over that evening to see an old bore. Politically she was an extreme conservative, unlike most of Feynman’s colleagues, and as the Oppenheimer security hearings began, she irritated Feynman by saying, “Where there’s smoke there’s fire.” He, too, voted Republican, at least for a while. Divorce was inevitable—Feynman realized early that they should not have children, he confided in his sister—but it was nearly four years before they finally separated.

By agreement he confessed to Extreme Cruelty—

has wilfully, wrongfully, and without provocation, justification or excuse whatsoever inflicted grievous physical and mental suffering … ; plaintiff has suffered great physical pain and grievous mental suffering, and has suffered physical nervous shock to the extent that further married life between plaintiff and defendant has been rendered impossible.

He agreed to a circumscribed alimony, a total of ten thousand dollars over the next three years. She kept their 1950 Oldsmobile and all their household furniture. He kept their 1951 Lincoln Cosmopolitan, his scientific books, “All Drums and Percussion Instruments,” and a set of dishes that his mother had given him. The divorce had a fleeting life in the national press—not because Feynman was a celebrity, but because columnists and cartoonists could not overlook the nature of the extreme cruelty: Prof Plays Bongos, Does Calculus in Bed. “The drums made terrific noise,” his wife had testified. And: “He begins working calculus problems in his head as soon as he awakens… . He did calculus while driving his car, while sitting in the living room and while lying in bed at night.”

One day near Thanksgiving 1954, as Southern California’s winter neared with no discernible change of season, the smog had rolled up from Los Angeles toward the northern hills that cradled Pasadena, and for a moment their shared discontents had become too much. Feynman wrote to Bethe begging for his old job back. His eyes smarted from the smog; Mary Lou was complaining that she could not see the beautiful colors of the trees. He said he would take any salary—he surrendered unconditionally.

Soon afterward, someone rushed up to him with news of a discovery by Walter Baade, an astronomer at Mount Wilson Observatory up in the San Gabriel Mountains, demonstrating that the stars of the distant universe were several times older than anyone had established before. Caltech in the fifties was becoming an international center of cosmological discovery. The same day, a young microbiologist told him of a discovery he had made, confirming the fundamental irreducibility of the DNA molecule as bacteria divide and divide again. With Linus Pauling and Max Delbrück on hand, Caltech had some of the leading lights of molecular genetics as the field was undergoing its sensational birth. Meanwhile, although Bethe had been thrilled by Feynman’s letter, he had to tell him that the most Cornell could offer on the spot was a temporary appointment.

Feynman changed his mind again. That same fall, Enrico Fermi died, and the University of Chicago decided to do whatever was necessary to hire Feynman. Its dean of the Division of Physical Sciences, Walter Bartky, and a younger physicist, Marvin Goldberger, later to become president of Caltech, traveled westward on the Super Chief—Bartky was afraid to fly—and took a taxi directly from the railway station to Feynman’s house. He refused to consider their proposition, and he begged them not even to tell him how much money they were offering. He was worried, he said, that Mary Lou would hear the amount and insist on moving. He had decided. He was going to stay at Caltech.

Onward with Physics

Where next, in the newly illuminated quantum world?

Feynman had reached maturity at a moment when the community of theoretical physicists shared a great unsolved problem, such a weighty knot that the enterprise could scarcely move forward until it was untied or cut. Now that quantum electrodynamics had been solved, no single problem seemed as universally compelling. Most theoretical physicists turned convoy fashion toward the smaller atomic distances and smaller time scales at which new particles appeared. They were driven in part by the logic of the past century’s history: each new step inward toward the atom’s core had brought not just new revelations but also a new simplification. The periodic table of elements had once served as a powerful unifying scheme; now it seemed more like a taxonomical catalog, itself unified by the deeper principles revealed by the quest inside the atom. A rhetoric was appearing in popular writing about physics by physicists and journalists: catchwords were fundamental and constituents of matter and building blocks of nature and innermost sanctum of matter. The phrases were seductive. Other kinds of science sought laws of nature, but a kind of priority seemed to belong to the search for elementary units.

The prestige of particle physics also rose with a flood tide of military support. Most plainly, the weapons laboratories prospered and such agencies as the Office of Naval Research financed specific military research projects.

A host of applied sciences, from electronics to cryptography, benefited from the concrete interest of military program officers. Academic scientists could immediately see the potential danger of allowing the armed forces to direct the course of scientific research. “When science is allowed to exist merely from the crumbs that fall from the table of a weapons development program,” said Caltech’s new president, Lee DuBridge, “then science is headed into the stifling atmosphere of ‘mobilized secrecy’ and it is surely doomed—even though the crumbs themselves should provide more than adequate nourishment.” Yet the military also recognized this. One of the many legacies of the Manhattan Project was that generals and admirals now believed the scientists’ dogma: that researchers left alone to follow their instincts will lay golden eggs. The bomb had been born of the esoteric fancies of the mandarins—that was clear. Now pure physicists wished to conduct basic research into forces and particles even stranger than those powering atomic bombs; the public and the government supported them enthusiastically. At institutions like DuBridge’s Caltech, even the theoretical programs of research on particle physics flourished by accepting enormous government grants to which the professors applied in groups. The grants paid for salaries, graduate students, office expenses, and university overhead. The military actively encouraged, when it did not finance directly, the giant cyclotrons, betatrons, synchrotrons, and synchrocyclotrons, any one of which consumed more steel and electricity than a prewar experimentalist could have imagined. These were not so much crumbs from the weapons-development table as they were blank checks from officials persuaded that physics worked miracles. Who could say what was impossible? Free energy? Time travel? Antigravity? In 1954 the secretary of the army invited Feynman to serve as a paid consultant on an army scientific advisory panel, and he agreed, traveling to Washington for several days in November. At a cocktail party after one session, a general confided that what the army really needed was a tank that could use sand as fuel.

Earlier that year Feynman had picked up the telephone in Pasadena to hear the chairman of the AEC, Admiral Lewis L. Strauss, say that he had won his first major prize, the Albert Einstein Award: fifteen thousand dollars and a gold medal. He was the third winner, after Kurt Gödel and Julian Schwinger. Strauss informed him of the award (Feynman amused him by saying, “Hot dog!”). The public announcement came from Oppenheimer as director of the Institute for Advanced Study. Only gradually did it occur to Feynman that this was the same Strauss who was in the process of permanently removing Oppenheimer from public life. Strauss had carried out President Dwight D. Eisenhower’s order to strip Oppenheimer of his security clearance, after a letter to J. Edgar Hoover accused him, in the fashion of the time, of being a “hardened Communist” who was probably “functioning as an espionage agent.” The AEC began four weeks of hearings in April. Many physicists publicly defended the man they had so admired over the past decade. The famous, damaging exception was Teller, who complained that Oppenheimer had not supported his hydrogen bomb project and testified, choosing his words carefully, “I feel that I would like to see the vital interests of this country in hands which I understand better, and therefore trust more.” Under the circumstances Feynman did not relish the prospect of accepting the award from Strauss. But Rabi, who was visiting Caltech, advised him to go ahead. “You should never turn a man’s generosity as a sword against him,” he recalled Rabi saying. “Any virtue that a man has, even if he has many vices, should not be used as a tool against him.”

In the frightened climate, atomic scientists developed an invisible trail of agents, questioning their friends and childhood neighbors, painstakingly uncovering the obvious, trying to tune in to a hearsay of who liked whom, who resented whom, who might be likely to inform on whom. Feynman’s own file at the FBI grew bulky. His Los Alamos friend Klaus Fuchs had been imprisoned in 1950 for spying for the Soviet Union. Fortunately for Feynman, the bureau did not realize how often Fuchs had lent Feynman his car. It was noted that Feynman had once made a speech at Temple Israel in Far Rockaway, “at which time he had spoken on brotherhood.” He was described as a shy, retiring, introverted type of individual. Neighbors vouched for his loyalty and doubted that he had participated in the high school’s Young People’s Socialist League, which an investigating agent described as “a militant, pro-communistic group of students.” Bethe was pestered by an officer of the Department of Commerce for information regarding Feynman’s “loyalty.” Finally he replied curtly, “Professor Feynman is one of the leading theoretical physicists of the world. His loyalty to the United States is unquestioned. Any further elaboration would be an insult to Dr. Feynman.”

On one occasion the bureau discovered a “contact by Oppenheimer with one ‘FINEMAN’ (phonetic)” and surmised “that this ‘FINEMAN’ is in fact subject RICHARD FEYNMAN.” Officials discussed the possibility of turning him into a confidential informant against Oppenheimer. They authorized a discreet approach and then placed Feynman on the “no contact” list when he refused to be interviewed by the bureau about anything at all. Agents interviewed his Los Alamos colleagues, who generally described him as a “prodigy” of “excellent character.” Yet it was learned that he sometimes boasted of having “out-foxed” the Selective Service psychiatrists to obtain a 4-F classification. One colleague considered him a “screwball.” Another felt that his interest in “jazz” was not in keeping with the usual demeanor of a physics professor. Yet he had voted for Eisenhower, according to informants, registered Independent (not to be confused with Independent Progressive), and “had no respect whatsoever for the Russians.” The bureau carefully copied out newspaper accounts of his divorce. And one oddity had to be reported:

FEYNMAN has developed a fair degree of skill opening sample tumbler and Yale type locks with hairpins, bits of wire, etc… . Feynman has been trying to learn the workings of safe locks and has expressed an ambition to be able to open a safe.

In this first report the agent tried diligently to understand the exculpatory opinion of the informant that “this was not indicative of any criminal tendencies on the part of Feynman but was merely one of the works of a brilliant mathematical mind challenged by a device considered practically impossible of solution by an ordinary individual.” Nevertheless, the suggestive combination of opened safes containing atomic secrets and socialized with Klaus Fuchs proved irresistible to the anonymous authors of memorandums, special inquiries, and secret airtels that swelled Feynman’s file for years to come.

The bureau monitored one other incident with particular interest. The Soviet Academy of Sciences invited Feynman to a conference in Moscow, where he would have had a chance to meet the great Lev Landau and other Russian physicists. Nuclear physics, particularly in its sensitive guises, was not on the agenda. Still, the cream of Soviet physics was engaged in a weapons program quickly catching up with the Americans’. That year the Russians exploded an advanced, portable thermonuclear bomb over Siberia. (One of its principal architects, the future dissident Andrei Sakharov, watched from a platform on the snowy steppe, miles from ground zero. Having read an American primer called the black book, he decided it would be safe to remove his dark goggles.) Feynman accepted the invitation enthusiastically, the Soviet Academy having offered to cover his travel expenses. Then he had second thoughts. He wrote a careful letter to the AEC to ask for the government’s advice. “I thought you would be interested,” he said, “because I was connected to the Los Alamos project during the war, so the danger that I might not be able to return, or the attitude of public opinion must be considered.” After a delay, officials at both the commission and the State Department replied, asking him to turn the Soviets down. His presence might be exploited for “propaganda gains.” Feynman acquiesced. He wrote the head of the Soviet Academy that “circumstances have arisen which make it impossible for me to attend.” The government also forced Freeman Dyson to withdraw, warning him that under the McCarran Immigration Act he might not be allowed back into the United States. Dyson did not surrender so quietly, however. He told newspaper reporters, “This is a clear case in which the law has been proved stupid.”

In their basic, nonweapons research, Russian physicists eagerly pursued the latest developments in the United States and Europe. Yet a faint difference in outlook between East and West was already unfolding. The triumph of the atomic bomb had been an American triumph, had won the American war, and had not ingrained itself so firmly into the Soviet psyche (obsessed though policymakers were with the arms race). Although an international-class synchrocyclotron went up in Dubno, money was not so readily available for giant particle accelerators of the kind now under construction in the United States. And the most influential single figure in Soviet physics was Landau, famous for the catholicity of his interests across the whole breadth of phenomena that could be called theoretical physics. He had devoted his greatest work not to elementary particles but to condensed matter: the dynamics of fluids, transitions between one phase of matter and another, turbulence, plasmas, sound dispersion, and low-temperature physics. Fundamental though all these subjects were, in the United States their status was beginning to dim slightly next to the glamour of particle physics. Not so in the Soviet Union, where physicists were particularly eager in 1955 to meet Feynman. For his first major work since quantum electrodynamics, he had turned away from particle physics after all and chosen instead a subject close to Landau’s heart: a theory of superfluidity, the frictionless motion of liquid helium cooled to near absolute zero.

A Quantum Liquid

By then science-fiction writers had learned an interesting rule: not to let their imaginations run too freely, too widely. It was often better to be conservative. To create a strange new world, they had only to alter one or two features of the usual reality and let the manifold unexpected implications play themselves out. Nature, too, seemed capable of adjusting a single rule and thereby creating the most bizarre phenomena.

Superfluid helium showed what happens when a liquid can flow with no friction—not just low friction, but zero friction. Resting in a beaker, the liquid spontaneously glides in a thin film up and over the walls, apparently in defiance of gravity. It passes through cracks or holes so microscopically small that even a gas would not fit through. No matter how perfectly a pair of glass plates are polished to a smooth surface, and no matter how hard they are pressed together, superfluid helium will still flow freely between them. The liquid conducts heat far better than any ordinary substance, and no amount of cooling will freeze it into a solid.

When Feynman talked about fluid flow, he knew he was returning to a childlike, elemental fascination with the world as it is. The pleasure of watching water in bathtubs or mud puddles on the sidewalk, of trying to dam a curbside rivulet after a rainstorm, of contemplating the movement in waterfalls and whirlpools—that was what made every child a physicist, he felt. In trying to understand superfluidity, he began once again with first principles. What was a fluid? A substance, liquid or gas, that cannot withstand a shear stress, but moves under the force. The tendency of a fluid to resist the shear is its viscosity, its internal friction—honey being more viscous than water, water more than air. Nineteenth-century physicists creating the first effective equations for fluid flow found viscosity especially troublesome, so uncomputable were its consequences. For the sake of simplicity, they often created models that ignored viscosity—and for that John von Neumann later mocked them. Modelers always tried to omit unnecessary complication—that was one thing. But classical fluid dynamicists had omitted what seemed an essential, defining quality. Sarcastically von Neumann called them theorists of “dry water.” Superfluid helium, Feynman said, resembled that impossible idealization, fluid without viscosity. It was dry water.

Superfluidity had an equally bizarre twin, superconductivity, the flow of electricity with no dissipation or resistance. Both were phenomena of low-temperature experimentation. Superconductivity had been discovered in 1911; superfluidity not until 1938, because of the difficulties of watching the behavior of a liquid inside a pinhead-size container in a supercooled cryostat. Esoteric though they were, by the fifties this pair of phenomena had become crown jewels of the side of theoretical physics not devoted to elementary particles. Little progress had been made in understanding the perpetual-motion machinery that seemed to be at work. It seemed to Feynman that they were like “two cities under siege … completely surrounded by knowledge although they themselves remained isolated and unassailable.” Besides Landau, the chief contributor to the theorizing on superfluidity was Lars Onsager, the distinguished Yale chemist whose notoriously difficult courses in statistical mechanics were sometimes called (in allusion to Onsager’s accent) Norwegian I and Norwegian II.

Nature had exhibited another kind of perpetual motion, familiar to quantum physicists: motion at the level of electrons in the atom. No friction or dissipation slowed electrons. Only in the interactions of crowds of atoms did the energy drain of friction arise. Were these super phenomena somehow escaping the incoherent tumult of classical matter? Was this a case of quantum mechanics writ large? Could the whole apparatus of wave functions, energy levels, and quantum states translate itself onto macroscopic scales? The most basic clue that this was indeed large-scale quantum behavior came from the apparent unwillingness of helium to freeze into hard crystals at any temperature. Classically, absolute zero was often described as the temperature at which all motion ceases. Quantum mechanically, there is no such temperature. Atomic motion never does cease. That precise a zero would violate the uncertainty principle.

Landau and others had set the stage with a handful of useful conceptions of liquid helium. One powerful idea, which continued to dominate all kinds of solid-state physics, was the notion of new entities—“quasiparticles” or “elementary excitations”—collective motions that traveled through matter and interacted with one another as if they were particles. Quantum sound waves, now called phonons, were one example. Another: liquid helium seemed to contain units of rotational motion christened rotons. Feynman tried to work out the implications of these ideas. He also explored the notion that liquid helium acts as though it were (here, as elsewhere, the old-fashioned is had to be permanently replaced by the provisional acts as though it were) a mixture of two coexisting substances, a normal liquid and a pure superfluid.

One of the strangest of all the liquid-helium manifestations demonstrated how the mixture would work. A circular tube like a bicycle tire was packed with powder and then filled with liquid helium. It was set spinning and then abruptly halted. The powder would halt the flow of any normal liquid. But the superfluid component of liquid helium would continue to flow, around and around, passing through the microscopic interstices in the powder, in effect ignoring the presence of another, normal liquid. Students could sense the flow by feeling the tire’s resistance to torque, as a spinning gyroscope resists sidelong pressure. And, once set in motion, the superflow would persist as long as the universe itself.

At a meeting in New York of the American Physical Society in 1955 Feynman startled a Yale group, students of Onsager, who described a new experiment they were conducting with rotating buckets. (In the low-temperature business “buckets” tended to be glass tubes the size of a thimble.) Feynman rose and said that a rotating bucket of superfluid would be filled with peculiar vortices, whirlpools hanging down like strings. The speakers had no idea what he was talking about. This peculiar image was the essence of his visualization of the atomic behavior of liquid helium. He had tried to picture how individual atoms would move together within the fluid; he calculated the forces between them as directly as he could, with tools dating back to his undergraduate research with John Slater. He saw that rotational motions would arise, just as Landau had suggested, and he applied the quantum-mechanical restriction that such motion would have to come in indivisible units. For a while he struggled to find the right image for an elementary excitation in a superfluid. He considered an atom in a cage, oscillating. A pair of atoms revolving one around the other. A tiny rotating ring of atoms. The challenge was to drive toward a solution of a many-particle problem in quantum mechanics without being able to begin with a formal, mathematical line of reasoning. It was a challenge in pure visualization.

He lay awake in bed one night trying to imagine how rotation could arise at all. He imagined a liquid divided by a thin sheet, an imaginary impermeable membrane. On one side the liquid was motionless; on the other side it flowed. He knew how to write the old-fashioned Schrödinger wave function for both sides. Then he imagined the sheet disappearing. How could he make the wave functions join? He thought about the different phases combining. He imagined a kind of surface tension, energy proportional to the surface area of his sheet. He considered what would happen when an individual atom moved across the boundary—at what point in the rising and falling wave of energy the surface tension would fall to zero and the atom would be able to move freely. He was starting to see a surface divided into strips of glue, where the atoms could not mix, and other narrow strips where atoms would be able to change places. He calculated how little energy it would take to distort the wave function until the atoms would be held back, and realized that the strips of free motion would be no more than the width of a single atom. Then he realized that he was seeing lines, vortex lines around which the atoms circulated in rings. The rings of atoms were like rings of children waiting to use a playground slide. As each child descended—the wave function changing from plus to minus—another would slip into position at the top. But the fluid version was more than just a two-dimensional ring. It also wound back on itself through the third dimension—like a smoke ring, Feynman concluded, twenty years after he had led an investigation of smoke-ring dynamics in his high school physics club. These quantum smoke rings, or vortex lines, would circle about the tiniest conceivable hole, just one atom’s width across.

In a succession of articles spanning five years he worked out the consequences of his view of the interplay of energy and motion in this quantum fluid. The vortex lines were the fundamental units, the indivisible quanta of the system. They set limits on the ways in which energy could be exchanged within the fluid. In a thin enough tube, or a slow enough flow, the lines would not be able to form, and the flow would just coast, unchanging, losing no energy, and thus absolutely free of resistance. He showed when vortex lines would arise and when they would vanish. He showed when they would begin to entangle one another and ball up, creating another unexpected phenomenon that no one had yet seen in the laboratory: superfluid turbulence. Caltech hired low-temperature experimental specialists, and Feynman worked with them closely. He learned all the details of the apparatus, vacuum pumps for cooling by lowering the vapor pressure; rubber O-rings for ensuring tight seals. Before long, word was spreading of an experiment that struck physicists as “typical Feynman.” Tiny wings, airfoils, were attached to a thin quartz fiber hanging down through a tube. The superfluid was pulled through vertically. A normal fluid would have spun the wings like a tiny propeller, but the superfluid refused to cause twisting. Instead it slipped frictionlessly past. In their search for lighter and lighter airfoils, the experimenters finally killed some local flies, or so they claimed, and the investigation became known as the flies’-wings experiment.

Physicists who had worked in the area of condensed matter for longer than Feynman—and who would remain there after Feynman had once again departed—were struck by his method as much as by his success. He used none of the technical apparatus for which he was now famous: no Feynman diagrams, no path integrals. Instead he began with mental pictures: this electron pushes that one; this ion rebounds like a ball on a spring. He reminded colleagues of an artist who can capture the image of a human face with three or four minimal and expressive lines. Yet he did not always succeed. As he worked on superfluidity, he also struggled with superconductivity, and here, for once, he failed. (Yet he came close. At one point, about to leave on a trip, he wrote a single page of notes, beginning, “Possibly I understand the main origin of superconductivity.” He was focusing on a particular kind of phonon interaction and on one of the experimental signatures of superconductivity, a transition in a substance’s specific heat. He could see, as he jotted to himself, that there was “something still a little haywire,” but he thought he would be able to work out the difficulties. He signed the page: “In case I don’t return. R. P. Feynman.”) Three younger physicists, intensely aware of Feynman’s competitive presence—John Bardeen, Leon Cooper, and Robert Schrieffer—invented a successful theory in 1957. The year before, Schrieffer had listened intently as Feynman delivered a pellucid talk on the two phenomena: the problem he had solved, and the problem that had defeated him. Schrieffer had never heard a scientist outline in such loving detail a sequence leading to failure. Feynman was uncompromisingly frank about each false step, each faulty approximation, each flawed visualization.

No tricks or fancy calculations would suffice, Feynman said. The only way to solve the problem would be to guess the outline, the shape, the quality of the answer.

We have no excuse that there are not enough experiments, it has nothing to do with experiments. Our situation is unlike the field, say, of mesons, where we say, perhaps there aren’t yet enough clues for even a human mind to figure out what is the pattern. We should not even have to look at the experiments… . It is like looking in the back of the book for the answer … The only reason that we cannot do this problem of superconductivity is that we haven’t got enough imagination.

It fell to Schrieffer to transcribe Feynman’s talk for journal publication. He did not quite know what to do with the incomplete sentences and the frank confessions. He had never read a journal article so obviously spoken aloud. So he edited it. But Feynman made him change it all back.

New Particles, New Language

In the mere half-decade since the triumph of the new quantum electrodynamics the culture of high-energy physics had made and remade itself again and again. The language, the interests, and the machinery seemed to undergo a new transformation monthly. Experimentalists and theorists assembled yearly for meetings called Rochester conferences (after their initial site, Rochester, New York), descendants of the already mythic-seeming Shelter Island-Pocono-Oldstone meetings, but far larger and better financed, scores and then hundreds of participants. By the first of these meetings, at the close of 1950, quantum electrodynamics itself was already passé; it was so perfect experimentally and so far from the frontier of new forces and particles. That year had seen a kind of milestone, the discovery of a new particle not in cosmic rays but in an experimentalist’s accelerator. This was a neutral pi meson, or pion—“neutral” because it carried no charge. Actually, the experimenters did not so much detect the neutral pion as the pair of gamma rays into which it immediately decayed. This particle’s ephemerality made it less consequential in the everyday world of tables and chairs, chemistry and biology, than on this exciting frontier: it typically vanished after a lifetime of a tenth of a millionth of a billionth of a second. This qualified as a short time by 1950 standards. Yet standards were changing. Within a few years particle tabulations would list this fleeting entity in the category of STABLE. And meanwhile the legions of cosmic-ray explorers, many of them British, hoisting their photographic plates skyward with balloons, would find their specialty declining as spectacularly as it had risen. “Gentlemen, we have been invaded,” one of their leaders declared. “The accelerators are here.”

Of necessity physicists dispensed with their earlier squeamishness about the prospect of adding yet another particle to the already rich stew. On the contrary, an experimentalist could hardly aspire to more than the creation and discovery of a new particle. What it meant to measure these particles had also changed dramatically since the days when electrons had held center stage. Inferring the mass of a particle from the arcing traces left in a cloud chamber by its second- and third-generation decay products was not so simple. An enormous range of error had to be tolerated. It had become a serious and worthwhile intellectual challenge merely to identify the particles, to name them, to write down the rules of which particles could decay into which other particles. These rules were pithy new equations: π + p→π0 + n,, a pion with negative charge and a proton produce a neutral pion and a neutron. Never mind assessing the mass; it was hard enough to identify the objects of study. Declaring the existence or nonexistence of a certain particle became a delicate rite imbued with as much anticipation and judgment as declaring a rain delay at a baseball game.

This was the experimenters’ art, but, as the accelerator era began, Feynman took a special interest in the methodologies and pitfalls. He was influenced by Bethe, who always wanted to ground his theory in his own intuitions about the numbers, and by Fermi, the field’s last great combination of experimenter and theorist. Bethe spent time working out formulas for the probabilities of various wrong curvatures in cloud-chamber photographs. One experimentalist, Marcel Schein, set off a typical commotion with the announcement that he had discovered a new particle in cyclotron experiments. Bethe was suspicious. The energies seemed far too low to produce the kind of particle Schein described. Feynman forever remembered the confrontation between the two men, their faces eerily illuminated by the glow from the light table used to view the photographic plates. Bethe looked at one plate and said that the gas of the cloud chamber seemed to be swirling, distorting the curvatures. In the next plate, and the next, and the next, he saw different sources of potential error. Finally they came to a clean-looking photograph, and Bethe mentioned the statistical likelihood of errors. Schein said that Bethe’s own formula predicted only a one-in-five chance of error. Yes, Bethe replied, and we’ve already looked at five plates. To Feynman, looking on, it seemed like classic self-deception: a researcher believes in the result he is seeking, and he starts to overweight the favorable evidence and underweight the possible counterexamples. Schein finally said in frustration: You have a different theory for every case, while I have a single hypothesis that explains all at once. Bethe replied, Yes, and the difference is that each of my many explanations is right and your one explanation is wrong.

A few years later Feynman happened to be visiting Berkeley when experimenters excitedly thought they had discovered an antiproton—a particle clearly destined to be found at higher energies, but impossible, Feynman thought, at the mere hundreds of millions of electron volts available that year. As Bethe had, he went into a dark room to examine the photographs, a dozen questionable images and one that seemed absolutely perfect, the cornerstone of the discovery, with its track curving backward just as the antiparticle must.

There must be matter somewhere in the vacuum chamber, Feynman said.

Absolutely not, the experimenters told him—just thin glass walls on either side.

Feynman asked what held the upper and lower plates together. They said there were four small bolts.

He looked again at the white arc curving through the magnetic field. Then he jabbed his pencil down onto the table, inches away from the edge of the photograph. Right here, he said, must be one of those bolts.

The blueprint, retrieved from the files and laid out over the photograph, showed that his pencil had found the exact spot. An ordinary proton had struck the bolt and scattered backward into the picture. Later, experimenters at Caltech felt that Feynman’s very presence exerted a sort of moral pressure on their findings and methods. He was mercilessly skeptical. He loved to talk about the famous oil-drop experiment of Caltech’s first great physicist Robert Millikan, which revealed the indivisible unit charge of the electron by isolating it in tiny, floating oil drops. The experiment was right but some of the numbers were wrong—and the record of subsequent experimenters stood as a permanent embarrassment to physics. They did not cluster around the correct result; rather, they slowly closed in on it. Millikan’s error exerted a psychological pull, like a distant magnet forcing their observations off center. If a Caltech experimenter told Feynman about a result reached after a complex process of correcting data, Feynman was sure to ask how the experimenter had decided when to stop correcting, and whether that decision had been made before the experimenter could see what effect it would have on the outcome. It was all too easy to fall into the trap of correcting until the answer looked right. To avoid it required an intimate acquaintanceship with the rules of the scientist’s game. It also required not just honesty, but a sense that honesty required exertion.

As the particle era unfolded, however, it made other demands of top theorists—whose ranks, meanwhile, were expanding. They had to demonstrate new kinds of flair in sorting through the relations between particles. They competed to invent abstract concepts to help organize the information arriving from accelerators. A new quantum number like isotopic spin—a quantity that seemed to be conserved through many kinds of interactions—implied new incarnations of symmetry. This notion increasingly dominated the physicists’ discourse. Symmetry for physicists was not far removed from symmetry for children with paper and scissors: the idea that something remains the same when something else changes. Mirror symmetry is the sameness that remains after a reflection of left and right. Rotational symmetry is the sameness that remains when a system turns on an axis. Isotopic spin symmetry, as it happened, was the sameness that existed between the two components of the nucleus, the proton and the neutron, two particles whose relationship had been oddly close, one carrying charge and the other neutral, their masses nearly but not exactly identical. The new way to understand these particles was this: They were two states of a single entity, now called a nucleon. They differed only in their isotopic spin. One was “up,” the other “down.”

Theorists of the new generation had not only to master the quantum electrodynamics set forth by Feynman and Dyson. They also had to arm themselves with a rococo repertoire of methods suited to the new territory. Physicists had long utilized exotic variations of the idea of space—imaginary spaces in which the axes might represent quantities other than physical distance. “Momentum space,” for example, allowed them to plot and to visualize a particle’s momentum as though it were merely another spatial variable. One grew comfortable with such spaces, and now they were multiplying. Isotopic spin space became essential to understanding the strong forces acting on nucleons.

Other concepts, too, had to become second nature. Symmetries suggested that various particles must come in families: pairs, or triplets, or (as physicists now said) multiplets. Physicists experimented with what they called “selection rules”—rules about what must or must not happen in particle collisions on account of the conservation of quantities like charge. A physicist Feynman’s age, Abraham Pais, guessed at a rule called “associated production”—certain collisions must produce new particles in groups, preserving some putative new quantum number, the nature of which was unknown. Feynman had had a similar idea in Brazil but had not liked it enough to pursue it diligently. For a few years associated production became an important catchphrase. Experimenters looked for examples or counterexamples. In the longer term its main contribution to physics was that its popularity rankled a younger theorist, Murray Gell-Mann. He thought Pais was wrong, and he was jealous.


At fourteen he had been declared “Most Studious” and “wonder boy” by his classmates at Columbia Grammar, a private school on the Upper West Side of New York, and that was the last they saw of him, for he was already a senior, and he started at Yale that fall. Gell-Mann’s surname was subtly difficult to pronounce. It was wrong to unstress the second syllable, as if the name were Gelman, although Murray’s older brother, Benedict, had chosen that simpler spelling. Many people leaned the other way, toward a pedantic, European style of pronunciation, the accent on the second syllable and the a broad: gel-MAHN. This, too, was wrong. Later, when he had secretaries, they sometimes upbraided malefactors: “He’s not German, you know.” Of course the g was hard, despite the unconscious tug of the soft g in the word gel. Natives of New York and other regions that distinguish between the a’s of man and mat suspected rightly that the second, flatter a must be better for Gell-Mann. It was safest to stress the two syllables almost equally. By then anyone who knew anything about Gell-Mann knew that his own pronunciation of names in any language was impeccable. Supposedly he would lecture visitors from Strasbourg or Pago Pago about the niceties of their own Alsatian or Samoan dialects. He was so insistent about differentiating the pronunciations of Colombia and Columbia that colleagues suspected him of straining to bring references to the country into conversations about the university. From the beginning most physicists simply referred to him as Murray. There was never any doubt which Murray they meant. Feynman, preparing for a cameo performance as a tribal chieftain in a Caltech production of South Pacific, taught himself a few words of Samoan and then resignedly told a friend, “The only person who will know I’m pronouncing this wrong is Murray.”

Gell-Mann attended Columbia Grammar on full scholarship. His father, born in Austria, had learned to speak a perfectly unaccented English and so, in the early 1920s, decided to start a language school for immigrants. It was the closest to success that he came, as his son saw it. The school moved several times—once, as Murray recalled, because his mother was afraid that his brother would catch whooping cough from someone in the building—and went out of business a few years later. It was his brother, nine years older and so adored by his parents, who taught him to read and to take pleasure in language, science, and art. Benedict was a bird-watcher and nature lover before nature became a practical field of interest; dropping out of college at the height of the Depression, he stunned his parents and left a complicated impression on his younger brother.

Murray did not find his way immediately to physics, talented as he was in so many subjects. When he applied to the Ivy League graduate schools, he was widely disappointed: Yale would take him only in mathematics, Harvard would take him only if he paid full fare, and Princeton would not take him at all. So he made a half-hearted application to MIT and heard directly back from Victor Weisskopf, whom he had not heard of. Gell-Mann decided to accept Weisskopf’s offer, though grudgingly. MIT seemed so lumpen. The joke he told ever after was that the alternatives did not commute: he could try MIT first and suicide second, whereas the other ordering would not work. He reached MIT in 1948, close to his nineteenth birthday, just in time to watch the exploding competition in quantum electrodynamics from the vantage point of an office near Weisskopf’s. When Weisskopf advised him that the future belonged to Feynman, he studied the available preprints. Feynman’s struck him as a cuckoo private language, though correct; Schwinger’s version struck him as hollow and pompous; Dyson’s as crude and sloppy. He was already inclined toward scabrous assessments of his famous fellow physicists, though for now he kept them mostly private.

His own work was not quite living up to his severe expectations, though he was finally beginning to impress other physicists. After a year at the Institute for Advanced Study he joined Fermi’s group at Chicago. He was in time to join the tumultuous effort to find the right concepts, the right ordering principles, the right quantum numbers for understanding the many new particles. There was confusion and there were regularities—coincidences in the experimental plots of particle masses and lifetimes. There were mesons that seemed to exist, and mesons that seemed plausible but absent. There were even more mysterious particles called V-particles. The problem with these enormously massive items was that particle accelerators produced them copiously, with relative ease, yet they did not decay with corresponding ease. They lingered for as long as a billionth of a second. Pais’s approach to associated production had reached toward the heart of some of the regularities in need of explanation. It contained the crucial idea of another hidden symmetry. It was also reaching a peak of popularity: in the summer of 1953 Pais created such a stir at an international conference in Japan that Time magazine called him at his hotel. His roommate answered the phone—it happened to be Feynman, attending the same conference to present his liquid helium results. Feynman felt a flicker of envy when he realized that Time had no interest in him. Gell-Mann, in Chicago, felt even more, particularly since he now saw a far more powerful answer.

Physicists had learned to speak comfortably about four fundamental forces: gravity; electromagnetism, which dominated all chemical and electrical processes; the strong force binding the atom’s nucleus; and the weak force, at work in the slow processes of radioactive decay. The quick appearance and slow disappearance of V-particles suggested that their creation relied on strong forces and that weak forces came into play as they decayed. Gell-Mann proposed a new fundamental quantity, which for a while he called y. This y was like a new form of charge. Charge is conserved in particle events—the total going in equals the total coming out. Gell-Mann supposed that y is conserved, too—but not always. The algebraic logic of Gell-Mann’s scheme decreed that strong interactions would conserve y, and so would electromagnetic interactions, but weak interactions would not. They would break the symmetry. Thus strong interactions would create a pair of particles whose y had to cancel each other (1 and - 1, for example). Such a particle, having flown away from its sibling, could not decay through a strong interaction because there was no longer a canceling y. That gave the slower weak interaction time to take over.

Artificial though it was, Gell-Mann’s y qualified as not just a description but an explanation. As he conceived his framework, it was an organizing principle. It gave him a way of seeing families of particles, and its logic was so compelling that the families had obvious missing members. He was able to predict—and did predict, in papers he began publishing in August 1953—specific new particles not yet discovered, as well as specific particles that he insisted could not be discovered. His timing was perfect. Experimenters bore out each of his positive predictions (and failed to contradict the negative ones). But this was only part of Gell-Mann’s triumph. He also injected a piece of his fascination with language into the temporarily befuddled business of physics nomenclature. He decided to call his quantity y “strangeness” and the families of V-like particles “strange.” A Japanese physicist, Kazuhiko Nishijima, who had independently hit upon the same scheme just months after Gell-Mann, chose the considerably less friendly name “?-charge.” Amid all the -ons and Greek-lettered particles, strange sounded whimsical and unorthodox. The editors of the Physical Review would not allow “Strange Particles” in Gell-Mann’s title, insisting instead on “New Unstable Particles.” Pais did not like it either. He pleaded with the audience at a Rochester conference to avoid loaded terms like “strange.” Why should a broad-minded theorist consider one particle stranger than another? The quirkiness of the word had a distancing effect: perhaps this new construct was not quite as real as charge. But Gell-Mann’s command of language had an unstoppable force. Strangeness was only the beginning.

The winter Fermi died, just before Christmas 1954, Gell-Mann wrote to the one physicist who seemed to him utterly genuine, free of phoniness, the one who did not worship formalism and superficialities, whose own work was always sure to be interesting and real. Some of Feynman’s colleagues were already beginning to think that he had drifted away from the mainstream of particle physics, but it did not seem that way to Gell-Mann. On the contrary, he knew from their few conversations that Feynman was thinking about all the outstanding problems, all the time. Feynman responded in a friendly way. Gell-Mann visited Caltech to give a talk on his current work. The two men met privately and spoke for hours. Gell-Mann described work he had done extending Feynman’s quantum electrodynamics at short distances. Feynman said he knew of the work and admired it enormously—that in fact it was the only such work he had seen that he had not already done himself. He had pursued Gell-Mann’s line of thinking and generalized it further—he showed what he meant—and Gell-Mann said he thought that was wonderful.

Playing the bongos: “On the infrequent occasions when I have been called upon in a formal place to play the bongo drums, the introducer never seems to find it necessary to mention that I also do theoretical physics.”

Talking with a student as Murray Cell-Mann looks on: “Murray’s mask was a man ofgreat culture… Dick’s mask was Mr. Natural—just a little boy from the country that could see through things the city slickers can’t.”

With his hero, Paul A. M. Dirac, in Warsaw, 1962.

With Carl Feynman, three years old, facing photographers on the morning of the Nobel Prize: “Listen, buddy, if I could tell you in a minute what I did, it wouldn’t be worth the NobelPrize.”

Celebrating the Nobel Prize in Stockholm, 1965, with Gweneth Feynman (above) and a princess (below).

With Schwinger: “I thought you would be happy that I beat Schwinger out at last,” Feynman wrote his mother after winning one award, “but it turns out he got the thing 3 yrs ago.Of course, he only got 112 a medal, so 1guess you'll be happy. You always compareme with Schwinger.”

Shin’ichirō Tomonaga, whose work in an isolated Japan paralleled the new th eories of Feynman and Schwinger: “Why isn’t nature clearer and more directly comprehensible?”

With Carl and Michelle (right), and on a desert camping trip.

Standing at a Cal tech blackboard and playing a chieftain in a student production of South Pacific.

At the February 10, 1986, hearing of the presidential commission on the space shuttle accident: “I took this stuff that I got out of your sealand I put it in ice water,and I discovered that when you put some pressure on it fora while and then undo it it doesn't stretch back. It stays the same dimension. In other words, for a few seconds at least and moreseconds than that, there is no resilience in this particular material when it is at a temperature of 32 degrees. I believe that has somesignificance for our problem.”

By the beginning of the new year Caltech had made Gell-Mann an offer and Gell-Mann had accepted. He moved into an office just upstairs from Feynman’s. Caltech had now placed together in one building the two leading minds of their generation. To the close-knit, international community of physicists—a small world, no matter how rapidly it was growing—the collaborations and the rivalries between these men gained an epic quality. They were together, working or feuding, leaving their imprint on every area they cared to touch, for the rest of Feynman’s life. They gave their colleagues a long time to muse on how strikingly different were the ways in which a giant intellect might choose to reveal itself, even in the person of a modern theoretical physicist.

In Search of Genius

In the spring of 1955 the man most plainly and universally identified with the word genius died at Princeton Hospital. Most of his body was cremated, the ashes scattered, but not the brain. The hospital’s pathologist, Dr. Thomas S. Harvey, removed this last remnant to a jar of formaldehyde.

Harvey weighed it. A mediocre two and two-thirds pounds. One more negative datum to sabotage the notion that the brain’s size might account for the difference between ordinary and extraordinary mental ability—a notion that various nineteenth-century researchers had labored futilely to establish (claiming along the way to have demonstrated the superiority of men over women, white men over black men, and Germans over Frenchmen). The brain of the great mathematician Carl Friedrich Gauss had been turned over to such scientists. It disappointed them. Now, with Einstein’s cerebrum on their hands, researchers proposed more subtle ways of searching for the secret of genius: measuring the density of surrounding blood vessels, the percentage of glial cells, the degree of neuronal branching. Decades passed. Microscope sections and photographic slides of Einstein’s brain circulated among a tight circle of anatomically minded psychologists, called neuropsychologists, unable to let go the idea that a detectable sign of the qualities that made Einstein famous might remain somewhere in these fragmentary trophies. By the 1980s this most famous of brains had been whittled down to small gray shreds preserved in the office of a pathologist retired to Wichita, Kansas—a sodden testament to the elusiveness of the quality called genius.

Eventually the findings were inconclusive, though that did not make them unpublishable. (One researcher counted a large excess of branching cells in the parietal sector called Brodmann area 39.) Those searching for genius’s corporeal basis had little enough material from which to work. “Is there a neurological substrate for talent?” asked the editors of one neuropsychology volume. “Of course, as neuropsychologists we hypothesize that there must be such a substrate and would hardly think to relegate talent somehow to ‘mind.’ What evidence currently exists would be the results of the work on Einstein’s brain …”—the brain that created the post-Newtonian universe, that released the pins binding us to absolute space and time, that visualized (in its parietal lobe?) a plastic fourth dimension, that banished the ether, that refused to believe God played dice, that piloted such a kindly, forgetful form about the shaded streets of Princeton. There was only one Einstein. For schoolchildren and neuropsychologists alike, he stood as an icon of intellectual power. He seemed—but was this true?—to have possessed a rare and distinct quality, genius as an essence, not a mere statistical extremum on a supposed bell-curve of intelligence. This was the conundrum of genius. Was genius truly special? Or was it a matter of degree—a miler breaking 3:50 rather than 4:10? (A shifting bell-curve, too: yesterday’s record-setter, today’s also-ran.) Meanwhile, no one had thought to dissect the brains of Niels Bohr, Paul A. M. Dirac, Enrico Fermi; Sigmund Freud, Pablo Picasso, Virginia Woolf; Jascha Heifetz, Isadora Duncan, Babe Ruth; or any of the other exceptional, creative, intuitive souls to whom the word was so often and so lubricously applied.

What a strange and bewildering literature grew up around the term genius—defining it, analyzing it, categorizing it, rationalizing and reifying it. Commentators have contrasted it with such qualities as (mere) talent, intellect, imagination, originality, industriousness, sweep of mind and elegance of style; or have shown how genius is composed of these in various combinations. Psychologists and philosophers, musicologists and art critics, historians of science and scientists themselves have all stepped into this quagmire, a capacious one. Their several centuries of labor have produced no consensus on any of the necessary questions. Is there such a quality? If so, where does it come from? (A glial surplus in Brodmann area 39? A doting, faintly unsuccessful father who channels his intellectual ambition into his son? A frightful early encounter with the unknown, such as death of a sibling?) When otherwise sober scientists speak of the genius as magician, wizard, or superhuman, are they merely indulging in a flight of literary fancy? When people speak of the borderline between genius and madness, why is it so evident what they mean? And a question that has barely been asked (the where-are-the-.400-hitters question): Why, as the pool of available humans has risen from one hundred million to one billion to five billion, has the production of geniuses—Shakespeares, Newtons, Mozarts, Einsteins—seemingly choked off to nothing, genius itself coming to seem like the property of the past?

“Enlightened, penetrating, and capacious minds,” as William Duff chose to put it two hundred years ago, speaking of such exemplars as Homer, Quintilian, and Michelangelo in one of a string of influential essays by mid-eighteenth-century Englishmen that gave birth to the modern meaning of the word genius. Earlier, it had meant spirit, the magical spirit of a jinni or more often the spirit of a nation. Duff and his contemporaries wished to identify genius with the godlike power of invention, of creation, of making what never was before, and to do so they had to create a psychology of imagination: imagination with a “RAMBLING and VOLATILE power”; imagination “perpetually attempting to soar” and “apt to deviate into the mazes of error.”

Imagination is that faculty whereby the mind not only reflects on its own operations, but which assembles the various ideas conveyed to the understanding by the canal of sensation, and treasured up in the repository of the memory, compounding or disjoining them at pleasure; and which, by its plastic power of inventing new associations of ideas, and of combining them with infinite variety, is enabled to present a creation of its own, and to exhibit scenes and objects which never existed in nature.

These were qualities that remained two centuries later at the center of cognitive scientists’ efforts to understand creativity: the mind’s capacity for self-reflection, self-reference, self-comprehension; the dynamical and fluid creation of concepts and associations. The early essayists on genius, writing with a proper earnestness, attempting to reduce and regularize a phenomenon with (they admitted) an odor of the inexplicable, nevertheless saw that genius allowed a certain recklessness, even a lack of craftsmanship. Genius seemed natural, unlearned, uncultivated. Shakespeare was—“in point of genius,” Alexander Gerard wrote in 1774—Milton’s superior, despite a “defective” handling of poetic details. The torrent of analyses and polemics on genius that appeared in those years introduced a rhetoric of ranking and comparing that became a standard method of the literature. Homer versus Virgil, Milton versus Virgil, Shakespeare versus Milton. The results—a sort of tennis ladder for the genius league—did not always wear well with the passage of time. Newton versus Bacon? In Gerard’s view Newton’s discoveries amounted to a filling in of a framework developed with more profound originality by Bacon—“who, without any assistance, sketched out the whole design.” Still, there were those bits of Newtonian mathematics to consider. On reflection Gerard chose to leave for posterity “a question of very difficult solution, which of the two had the greatest genius.”

He and his contemporary essayists had a purpose. By understanding genius, rationalizing it, celebrating it, and teasing out its mechanisms, perhaps they could make the process of discovery and invention less accidental. In later times that motivation has not disappeared. More overtly than ever, the nature of genius—genius as the engine of scientific discovery—has become an issue bound up with the economic fortunes of nations. Amid the vast modern network of universities, corporate laboratories, and national science foundations has arisen an awareness that the best financed and best organized of research enterprises have not learned to engender, perhaps not even to recognize, world-turning originality.

Genius, Gerard summed up in 1774, “is confessed to be a subject of capital importance, without the knowledge of which a regular method of invention cannot be established, and useful discoveries must continue to be made, as they have generally been made hitherto, merely by chance.” Hitherto, as well. In our time he continues to be echoed by historians of science frustrated by the sheer ineffability of it all. But they keep trying to replace awe with understanding. J. D. Bernal said in 1939:

It is one of the hopes of the science of science that, by careful analysis of past discovery, we shall find a way of separating the effects of good organization from those of pure luck, and enabling us to operate on calculated risks rather than blind chance.

Yet how could anyone rationalize a quality as fleeting and accident-prone as a genius’s inspiration: Archimedes and his bath, Newton and his apple? People love stories about geniuses as alien heroes, possessing a quality beyond human understanding, and scientists may be the world’s happiest consumers of such stories. A modern example:

A physicist studying quantum field theory with Murray Gell-Mann at the California Institute of Technology in the 1950s, before standard texts have become available, discovers unpublished lecture notes by Richard Feynman, circulating samizdat style. He asks Gell-Mann about them. Gell-Mann says no, Dick’s methods are not the same as the methods used here. The student asks, well, what are Feynman’s methods? Gell-Mann leans coyly against the blackboard and says, Dick’s method is this. You write down the problem. You think very hard. (He shuts his eyes and presses his knuckles parodically to his forehead.) Then you write down the answer.

The same story appeared over and over again. It was an old genre. From an 1851 tract titled Genius and Industry:

(A professor from the University of Cambridge calls upon a genius of mathematics working in Manchester as a lowly clerk.) “… from Geometry to Logarithms, and to the Differential and Integral Calculus; and thence again to questions the most foreign and profound: at last, a question was proposed to the poor clerka question which weeks had been required to solve. Upon a simple slip of paper it was answered immediately. ‘But how,’ said the Professor, ‘do you work this? show me the rule! … The answer is correct but you have reached it by a different way.’

“‘I have worked it,’ said the clerk, ‘from a rule in my own mind. I cannot show you the lawI never saw it myself; the law is in my mind.’

“‘Ah!’ said the Professor, ‘if you talk of a law within your mind, I have done; I cannot follow you there.’”

Magicians again. As Mark Kac said: “… The working of their minds is for all intents and purposes incomprehensible. Even after we understand what they have done, the process by which they have done it is completely dark.” The notion places a few individuals at the margin of their community—the impractical margin, since the stock in trade of the scientist is the method that can be transferred from one practitioner to the next.

If the most distinguished physicists and mathematicians believe in the genius as magician, it is partly for psychological protection. A merely excellent scientist could suffer an unpleasant shock when he discussed his work with Feynman. It happened again and again: physicists would wait for an opportunity to get Feynman’s judgment of a result on which they had staked weeks or months of their career. Typically Feynman would refuse to allow them to give a full explanation. He said it spoiled his fun. He would let them describe just the outline of the problem before he would jump up and say, Oh, I know that … and scrawl on the blackboard not his visitor’s result, A, but a harder, more general theorem, X. So A (about to be mailed, perhaps, to the Physical Review) was merely a special case. This could cause pain. Sometimes it was not clear whether Feynman’s lightning answers came from instantaneous calculation or from a storehouse of previously worked-out—and unpublished—knowledge. The astrophysicist Willy Fowler proposed at a Caltech seminar in the 1960s that quasars—mysterious blazing radiation sources lately discovered in the distant sky—were supermassive stars, and Feynman immediately rose, astonishingly, to say that such objects would be gravitationally unstable. Furthermore, he said that the instability followed from general relativity. The claim required a calculation of the subtle countervailing effects of stellar forces and relativistic gravity. Fowler thought he was talking through his hat. A colleague later discovered that Feynman had done a hundred pages of work on the problem years before. The Chicago astrophysicist Subrahmanyan Chandrasekhar independently produced Feynman’s result—it was part of the work for which he won a Nobel Prize twenty years later. Feynman himself never bothered to publish. Someone with a new idea always risked finding, as one colleague said, “that Feynman had signed the guest book and already left.”

A great physicist who accumulated knowledge without taking the trouble to publish could be a genuine danger to his colleagues. At best it was unnerving to learn that one’s potentially career-advancing discovery had been, to Feynman, below the threshold of publishability. At worst it undermined one’s confidence in the landscape of the known and not known. There was an uneasy subtext to the genus of story prompted by this habit. It was said of Lars Onsager, for example, that a visitor would ask him about a new result; sitting in his office chair he would say, I believe that is correct; then he would bend forward diffidently to open a file drawer, glance sidelong at a long-buried page of notes, and say, Yes, I thought so; that is correct. This was not always precisely what the visitor had hoped to hear.

A person with a mysterious storehouse of unwritten knowledge was a wizard. So was a person with the power to tease from nature its hidden secrets—a scientist, that is. The modern scientist’s view of his quest harkened back to something ancient and cabalistic: laws, rules, symmetries hidden just beneath the visible surface. Sometimes this view of the search for knowledge became overwhelming, even oppressive. John Maynard Keynes, facing a small audience in a darkened room at Cambridge a few years before his death, spoke of Newton as “this strange spirit, who was tempted by the Devil to believe … that he could reach all the secrets of God and Nature by the pure power of mind—Copernicus and Faustus in one.”

Why do I call him a magician? Because he looked on the whole universe and all that is in it as a riddle, as a secret which could be read by applying pure thought to certain evidence, certain mystic clues which God had laid about the world to allow a sort of philosopher’s treasure hunt to this esoteric brotherhood… . He did read the riddle of the heavens. And he believed that by the same powers of his introspective imagination he would read the riddle of the Godhead, the riddle of past and future events divinely foreordained, the riddle of the elements and their constitution… .

In his audience, intently absorbing these words, aware of the cold and the gloom and the seeming exhaustion of the speaker, was the young Freeman Dyson. Dyson came to accept much of Keynes’s view of genius, winnowing away the seeming mysticism. He made the case for magicians in the calmest, most rational way. No “magical mumbo-jumbo,” he wrote. “I am suggesting that anyone who is transcendentally great as a scientist is likely also to have personal qualities that ordinary people would consider in some sense superhuman.” The greatest scientists are deliverers and destroyers, he said. Those are myths, of course, but myths are part of the reality of the scientific enterprise.

When Keynes, in that Cambridge gloom, described Newton as a wizard, he was actually pressing back to a moderate view of genius—for after the eighteenth century’s sober tracts had come a wild turning. Where the first writers on genius had noticed in Homer and Shakespeare a forgivable disregard for the niceties of prosody, the romantics of the late nineteenth century saw powerful, liberating heroes, throwing off shackles, defying God and convention. They also saw a bent of mind that could turn fully pathological. Genius was linked with insanity—was insanity. That feeling of divine inspiration, the breath of revelation seemingly from without, actually came from within, where melancholy and madness twisted the brain. The roots of this idea were old. “Oh! how near are genius and madness!” Denis Diderot had written. “… Men imprison them and chain them, or raise statues to them.” It was a side effect of the change in focus from God-centeredness to human-centeredness. The very notion of revelation, in the absence of a Revealer, became disturbing, particularly to those who experienced it: “… something profoundly convulsive and disturbing suddenly becomes visible and audible with indescribable definiteness and exactness,” Friedrich Nietzsche wrote. “One hears—one does not seek; one takes—one does not ask who gives: a thought flashes out like lightning… .” Genius now suggested Charles-Pierre Baudelaire or Ludwig van Beethoven, flying off the tracks of normality. Crooked roads, William Blake had said: “Improvement makes strait roads; but the crooked roads without Improvement are roads of Genius.”

An 1891 treatise on genius by Cesare Lombroso listed some associated symptoms. Degeneration. Rickets. Pallor. Emaciation. Left-handedness. A sense of the mind as a cauldron in tumult was emerging in European culture, along with an often contradictory hodgepodge of psychic terminology, all awaiting the genius of Freud to provide a structure and a coherent jargon. In the meantime: Misoneism. Vagabondage. Unconsciousness. More presumed clues to genius. Hyperesthesia. Amnesia. Originality. Fondness for special words. “Between the physiology of the man of genius, therefore, and the pathology of the insane,” Lombroso concluded, “there are many points of coincidence… .” The genius, disturbed as he is, makes errors and wrong turns that the ordinary person avoids. Still, these madmen, “despising and overcoming obstacles which would have dismayed the cool and deliberate mind—hasten by whole centuries the unfolding of truth.”

The notion never vanished; in fact it softened into a cliché. Geniuses display an undeniable obsessiveness resembling, at times, monomania. Geniuses of certain kinds—mathematicians, chess players, computer programmers—seem, if not mad, at least lacking in the social skills most easily identified with sanity. Nevertheless, the lunatic-genius-wizard did not play as well in America, notwithstanding the relatively unbuttoned examples of writers like Whitman and Melville. There was a reason. American genius as the nineteenth century neared its end was not busy making culture, playing with words, creating music and art, or otherwise impressing the academy. It was busy sending its output to the patent office. Alexander Graham Bell was a genius. Eli Whitney and Samuel Morse were geniuses. Let European romantics celebrate the genius as erotic hero (Don Juan) or the genius as martyr (Werther). Let them bend their definitions to accommodate the genius composers who succeeded Mozart, with their increasingly direct pipelines to the emotions. In America what newspapers already called the machine age was under way. The consummate genius, the genius who defined the word for the next generation, was Thomas Alva Edison.

By his own description he was no wizard, this Wizard of Menlo Park. Anyone who knew anything about Edison knew that his genius was ninety-nine percent perspiration. The stories that defined his style were not about inspiration in the mode of the Newtonian apple. They spoke of exhaustive, laborious trial and error: every conceivable lamp filament, from human hair to bamboo fiber. “I speak without exaggeration,” Edison declared (certainly exaggerating), “when I say that I have constructed three thousand different theories in connection with the electric light, each one of them reasonable and apparently likely to be true.” He added that he had methodically disproved 2,998 of them by experiment. He claimed to have carried out fifty thousand individual experiments on a particular type of battery. He had a classic American education: three months in a Michigan public school. The essential creativity that led him to the phonograph, the electric light, and more than a thousand other patented inventions was deliberately played down by those who built and those who absorbed his legend. Perhaps understandably so—for after centuries in which a rationalizing science had systematically drained magic from the world, the machine-shop inventions of Edison and other heroes were now loosing a magic with a frightening, transforming power. This magic buried itself in the walls of houses or beamed itself invisibly through the air.

“Mr. Edison is not a wizard,” reported a 1917 biography.

Like all people who have prodigiously assisted civilization, his processes are clear, logical and normal.

Wizardry is the expression of superhuman gifts and, as such, is an impossible thing… .

And yet, Mr. Edison can bid the voices of the dead to speak, and command men in their tombs to pass before our eyes.

“Edison was not a wizard,” announced a 1933 magazine article. “If he had what seems suspiciously like a magic touch, it was because he was markedly in harmony with his environment… .” And there the explication of Edisonian genius came more or less to an end. All that remained was to ask—but few did—one of those impossible late-night what if questions: What if Edison had never lived? What if this self-schooled, indefatigable mind with its knack for conceiving images of new devices, methods, processes had not been there when the flood began to break? The question answers itself, for it was a flood that Edison rode. Electricity had burst upon a world nearing the limits of merely mechanical ingenuity. The ability to understand and control currents of electrons had suddenly made possible a vast taxonomy of new machines—telegraphs, dynamos, lights, telephones, motors, heaters, devices to sew, grind, saw, toast, iron, and suck up dirt, all waiting at the misty edge of potentiality. No sooner had Hans Christian Oersted noticed, in 1820, that a current could move a compass needle than inventors—not just Samuel Morse but André-Marie Ampère and a half-dozen others—conceived of telegraphy. Even more people invented generators, and by the time enough pieces of technology had accumulated to make television possible, no one inventor could plausibly serve as its Edison.

The demystification of genius in the age of inventors shaped the scientific culture—with its plainspoken positivism, its experiment-oriented technical schools—that nurtured Feynman and his contemporaries in the twenties and thirties, even as the pendulum swung again toward the more mysterious, more intuitive, and conspicuously less practical image of Einstein. Edison may have changed the world, after all, but Einstein seemed to have reinvented it whole, by means of a single, incomprehensible act of visualization. He saw how the universe must be and announced that it was so. Not since Newton …

By then the profession of science was expanding rapidly, counting not hundreds but tens of thousands of practitioners. Clearly most of their work, most of science, was ordinary—as Freeman Dyson put it, a business of “honest craftsmen,” “solid work,” “collaborative efforts where to be reliable is more important than to be original.” In modern times it became almost impossible to talk about the processes of scientific change without echoing Thomas S. Kuhn, whose Structure of Scientific Revolutions so thoroughly changed the discourse of historians of science. Kuhn distinguished between normal science—problem solving, the fleshing out of existing frameworks, the unsurprising craft that occupies virtually all working researchers—and revolutions, the vertiginous intellectual upheavals through which knowledge lurches genuinely forward. Nothing in Kuhn’s scheme required individual genius to turn the crank of revolutions. Still, it was Einstein’s relativity, Heisenberg’s uncertainty, Wegener’s continental drift. The new mythology of revolutions dovetailed neatly with the older mythology of genius—minds breaking with the standard methods and seeing the world new. Dyson’s kind of genius destroyed and delivered. Schwinger’s quantum electrodynamics and Feynman’s may have been mathematically the same, but one was conservative and the other revolutionary. One extended an existing line of thought. The other broke with the past decisively enough to mystify its intended audience. One represented an ending: a mathematical style doomed to grow fatally overcomplex. The other, for those willing to follow Feynman into a new style of visualization, served as a beginning. Feynman’s style was risky, even megalomaniacal. Reflecting later on what had happened, Dyson saw his own goals, like Schwinger’s, as conservative (“I accepted the orthodox view … I was looking for a neat set of equations …”) and Feynman’s as visionary: “He was searching for general principles that would be flexible enough so that he could adapt them to anything in the universe.”

Other ways of seeking the source of scientific creativity had appeared. It seemed a long way from such an inspirational, how-to view of discovery to the view of neuropsychologists looking for a substrate, refusing to speak merely about “mind.” Why had mind become such a contemptible word to neuropsychologists? Because they saw the term as a soft escape route, a deus ex machina for a scientist short on explanations. Feynman himself learned about neurons; he taught himself some brain anatomy when trying to understand color vision; but usually he considered mind to be the level worth studying. Mind must be a sort of dynamical pattern, not so much founded in a neurological substrate as floating above it, independent of it. “So what is this mind of ours?” he remarked. “What are these atoms with consciousness?”

Last week’s potatoes! They can now remember what was going on in my mind a year ago—a mind which has long ago been replaced… . The atoms come into my brain, dance a dance, and then go out—there are always new atoms, but always doing the same dance, remembering what the dance was yesterday.

Genius was not a word in his customary vocabulary. Like many physicists he was wary of the term. Among scientists it became a kind of style violation, a faux pas suggesting greenhorn credulity, to use the word genius about a living colleague. Popular usage had cheapened the word. Almost anyone could be a genius for the duration of a magazine article. Briefly Stephen Hawking, a British cosmologist esteemed but not revered by his peers, developed a reputation among some nonscientists as Einstein’s heir to the mantle. For Hawking, who suffered from a progressively degenerative muscular disease, the image of genius was heightened by the drama of a formidable intelligence fighting to express itself within a withering body. Still, in terms of raw brilliance and hard accomplishment, a few score of his professional colleagues felt that he was no more a genius than they.

In part, scientists avoided the word because they did not believe in the concept. In part, the same scientists avoided it because they believed all too well, like Jews afraid to speak the name of Yahweh. It was generally safe to say only that Einstein had been a genius; after Einstein, perhaps Bohr, who had served as a guiding father figure during the formative era of quantum mechanics; after Bohr perhaps Dirac, perhaps Fermi, perhaps Bethe … All these seemed to deserve the term. Yet Bethe, with no obvious embarrassment or false modesty, would quote Mark Kac’s faintly oxymoronic assessment that Bethe’s genius was “ordinary,” by contrast to Feynman’s: “An ordinary genius is a fellow that you and I would be just as good as, if we were only many times better.” You and I would be just as good … Much of what passes for genius is mere excellence, the difference a matter of degree. A colleague of Fermi’s said: “Knowing what Fermi could do did not make me humble. You just realize that some people are smarter than you are, that’s all. You can’t run as fast as some people or do mathematics as fast as Fermi.”

In the domains of criticism that fell under the spell of structuralism and then deconstructionism, even this unmagical view of genius became suspect. Literary and music theory, and the history of science as well, lost interest not only in the old-fashioned sports-fan approach—Homer versus Virgil—but also in the very idea of genius itself as a quality in the possession of certain historical figures. Perhaps genius was an artifact of a culture’s psychology, a symptom of a particular form of hero worship. Reputations of greatness come and go, after all, propped up by the sociopolitical needs of an empowered sector of the community and then slapped away by a restructuring of the historical context. The music of Mozart strikes certain ears as evidence of genius, but it was not always so—critics of another time considered it prissy and bewigged—nor will it always be. In the modern style, to ask about his genius is to ask the wrong question. Even to ask why he was “better” than, say, Antonio Salieri would be the crudest of gaffes. A modern music theorist might, in his secret heart, carry an undeconstructed torch for Mozart, might feel the old damnably ineffable rapture; still he understands that genius is a relic of outmoded romanticism. Mozart’s listeners are as inextricable a part of the magic as the observer is a part of the quantum-mechanical equation. Their interests and desires help form the context without which the music is no more than an abstract sequence of notes—or so the argument goes. Mozart’s genius, if it existed at all, was not a substance, not even a quality of mind, but a byplay, a give and take within a cultural context.

How strange, then, that coolly rational scientists should be the last serious scholars to believe not just in genius but in geniuses; to maintain a mental pantheon of heroes; and to bow, with Mark Kac and Freeman Dyson, before the magicians.

“Genius is the fire that lights itself,” someone had said. Originality; imagination; the self-driving ability to set one’s mind free from the worn channels of tradition. Those who tried to take Feynman’s measure always came back to originality. “He was the most original mind of his generation,” declared Dyson. The generation coming up behind him, with the advantage of hindsight, still found nothing predictable in the paths of his thinking. If anything he seemed perversely and dangerously bent on disregarding standard methods. “I think if he had not been so quick people would have treated him as a brilliant quasi-crank, because he did spend a substantial amount of time going down what later turned out to be dead ends,” said Sidney Coleman, a theorist who first knew Feynman at Caltech in the fifties.

There are lots of people who are too original for their own good, and had Feynman not been as smart as he was, I think he would have been too original for his own good.

There was always an element of showboating in his character. He was like the guy that climbs Mont Blanc barefoot just to show that it can be done. A lot of things he did were to show, you didn’t have to do it that way, you can do it this other way. And this other way, in fact, was not as good as the first way, but it showed he was different.

Feynman continued to refuse to read the current literature, and he chided graduate students who would begin their work on a problem in the normal way, by checking what had already been done. That way, he told them, they would give up chances to find something original. Coleman said:

I suspect that Einstein had some of the same character. I’m sure Dick thought of that as a virtue, as noble. I don’t think it’s so. I think it’s kidding yourself. Those other guys are not all a collection of yo-yos. Sometimes it would be better to take the recent machinery they have built and not try to rebuild it, like reinventing the wheel.

I know people who are in fact very original and not cranky but have not done as good physics as they could have done because they were more concerned at a certain juncture with being original than with being right. Dick could get away with a lot because he was so goddamn smart. He really could climb Mont Blanc barefoot.

Coleman chose not to study with Feynman directly. Watching Feynman work, he said, was like going to the Chinese opera.

When he was doing work he was doing it in a way that was just—absolutely out of the grasp of understanding. You didn’t know where it was going, where it had gone so far, where to push it, what was the next step. With Dick the next step would somehow come out of—divine revelation.

So many of his witnesses observed the utter freedom of his flights of thought, yet when Feynman talked about his own methods he emphasized not freedom but constraints. The kind of imagination that takes blank paper, blank staves, or a blank canvas and fills it with something wholly new, wholly free—that, Feynman contended, was not the scientist’s imagination. Nor could one measure imagination as certain psychologists try to do, by displaying a picture and asking what will happen next. For Feynman the essence of the scientific imagination was a powerful and almost painful rule. What scientists create must match reality. It must match what is already known. Scientific creativity, he said, is imagination in a straitjacket. “The whole question of imagination in science is often misunderstood by people in other disciplines,” he said. “They overlook the fact that whatever we are allowed to imagine in science must be consistent with everything else we know… .” This is a conservative principle, implying that the existing framework of science is fundamentally sound, already a fair mirror of reality. Scientists, like the freer-seeming arts, feel the pressure to innovate, but in science the act of making something new contains the seeds of paradox. Innovation comes not through daring steps into unknown space,

not just some happy thoughts which we are free to make as we wish, but ideas which must be consistent with all the laws of physics we know. We can’t allow ourselves to seriously imagine things which are obviously in contradiction to the known laws of nature. And so our kind of imagination is quite a difficult game.

Creative artists in modern times have labored under the terrible weight of the demand for novelty. Mozart’s contemporaries expected him to work within a fixed, shared framework, not to break the bonds of convention. The standard forms of the sonata, symphony, and opera were established before his birth and hardly changed in his lifetime; the rules of harmonic progression made a cage as unyielding as the sonnet did for Shakespeare. As unyielding and as liberating—for later critics found the creators’ genius in the counterpoint of structure and freedom, rigor and inventiveness.

For the creative mind of the old school, inventing by pressing against constraints that seem ironclad, subtly bending a rod here or slipping a lock there, science has become the last refuge. The forms and constraints of scientific practice are held in place not just by the grounding in experiment but by the customs of a community more homogeneous and rule-bound than any community of artists. Scientists still speak unashamedly of reality, even in the quantum era, of objective truth, of a world independent of human construction, and they sometimes seem the last members of the intellectual universe to do so. Reality hobbles their imaginations. So does the ever more intricate assemblage of theorems, technologies, laboratory results, and mathematical formalisms that make up the body of known science. How, then, can the genius make a revolution? Feynman said, “Our imagination is stretched to the utmost, not, as in fiction, to imagine things which are not really there, but just to comprehend those things which are there.”

It was the problem he faced in the gloomiest days of 1946, when he was trying to find his way out of the mire that quantum mechanics had become. “We know so very much,” he wrote to his friend Welton, “and then subsume it into so very few equations that we can say we know very little (except these equations) … Then we think we have the physical picture with which to interpret the equations.” The freedom he found then was a freedom not from the equations but from the physical picture. He refused to let the form of the mathematics lock him into any one route to visualization: “There are so very few equations that I have found that many physical pictures can give the same equations. So I am spending my time in study—in seeing how many new viewpoints I can take of what is known.” By then Welton had mastered the field theory that was becoming standard, and he was surprised to discover that his old friend had not. Feynman seemed to hoard shadow pools of ignorance, seemed to protect himself from the light like a waking man who closes his eyes to preserve a fleeting image left over from a dream. He said later, “Maybe that’s why young people make success. They don’t know enough. Because when you know enough it’s obvious that every idea that you have is no good.” Welton, too, was persuaded that if Feynman had known more, he could not have innovated so well.

“Would I had phrases that are not known, utterances that are strange, in new language that has not been used, free from repetition, not an utterance which has grown stale, which men of old have spoken.” An Egyptian scribe fixed those words in stone at the very dawn of recorded utterance—already jaded, a millennium before Homer. Modern critics speak of the burden of the past and the anxiety of influence, and surely the need to innovate is an ancient part of the artist’s psyche, but novelty was never as crucial to the artist as it became in the twentieth century. The useful lifetime of a new form or genre was never so short. Artists never before felt so much pressure to violate such young traditions.

Meanwhile, before their eyes, the world has grown too vast and multifarious for the towering genius of the old kind. Artists struggle to keep their heads above the tide. Norman Mailer, publishing yet another novel doomed to fall short of ambitions formed in an earlier time, notices: “There are no large people any more. I’ve been studying Picasso lately and look at who his contemporaries were: Freud, Einstein.” He saw the change in his own lifetime without understanding it. (Few of those looking for genius understood where it had gone.) He appeared on a literary scene so narrow that conventional first novels by writers like James Jones made them appear plausible successors to Faulkner and Hemingway. He slowly sank into a thicket of hundreds of equally talented, original, and hard-driving novelists, each just as likely to be tagged as a budding genius. In a world into which Amis, Beckett, Cheever, Drabble, Ellison, Fuentes, Grass, Heller, Ishiguro, Jones, Kazantzakis, Lessing, Nabokov, Oates, Pym, Queneau, Roth, Solzhenitsyn, Theroux, Updike, Vargas Llosa, Waugh, Xue, Yates, and Zoshchenko—or any other two dozen fiction writers—had never been born, Mailer and any other potential genius would have had a better chance of towering. In a less crowded field, among shorter yardsticks, a novelist would not just have seemed bigger. He would have been bigger. Like species competing in ecological niches, he would have had a broader, richer space to explore and occupy. Instead the giants force one another into specialized corners of the intellectual landscape. They choose among domestic, suburban, rural, urban, demimondaine, Third World, realist, postrealist, semirealist, antirealist, surrealist, decadent, ultraist, expressionist, impressionist, naturalist, existentialist, metaphysical, romance, romanticist, neoromanticist, Marxist, picaresque, detective, comic, satiric, and countless other fictional modes—as sea squirts, hagfish, jellyfish, sharks, dolphins, whales, oysters, crabs, lobsters, and countless hordes of marine species subdivide the life-supporting possibilities of an ocean that was once, for billions of years, dominated quite happily by blue-green algae.

“Giants have not ceded to mere mortals,” the evolutionary theorist Stephen Jay Gould wrote in an iconoclastic 1983 essay. “Rather, the boundaries … have been restricted and the edges smoothed.” He was not talking about algae, artists, or paleontologists but about baseball players. Where are the .400 hitters? Why have they vanished into the mythic past, when technical skills, physical conditioning, and the population on which organized baseball draws have all improved? His answer: Baseball’s giants have dwindled into a more uniform landscape. Standards have risen. The distance between the best and worst batters, and between the best and worst pitchers, has fallen. Gould showed by statistical analysis that the extinction of the .400 hitter was only the more visible side of a general softening of extremes: the .100 hitter has faded as well. The best and worst all come closer to the average. Few fans like to imagine that Ted Williams would recede toward the mean in the modern major leagues, or that the overweight, hard-drinking Babe Ruth would fail to dominate the scientifically engineered physiques of his later competitors, or that dozens of today’s nameless young base-stealers could outrun Ty Cobb, but it is inevitably so. Enthusiasts of track and field cannot entertain the baseball fan’s nostalgia; their statistics measure athlete against nature instead of athlete against athlete, and the lesson from decade to decade is clear. There is such a thing as progress. Nostalgia conceals it while magnifying the geniuses of the past. A nostalgic music lover will put on a scratchy 78 of Lauritz Melchior and sigh that there are no Wagnerian tenors any more. Yet in reality musical athletes have probably fared no worse than any other kind.

Is it only nostalgia that makes genius seem to belong to the past? Giants did walk the earth—Shakespeare, Newton, Michelangelo, DiMaggio—and in their shadows the poets, scientists, artists, and baseball players of today crouch like pygmies. No one will ever again create a King Lear or hit safely in fifty-six consecutive games, it seems. Yet the raw material of genius—whatever combination of native talent and cultural opportunity that might be—can scarcely have disappeared. On a planet of five billion people, parcels of genes with Einsteinian potential must appear from time to time, and presumably more often than ever before. Some of those parcels must be as well nurtured as Einstein’s, in a world richer and better educated than ever before. Of course genius is exceptional and statistics-defying. Still, the modern would-be Mozart must contend with certain statistics: that the entire educated population of eighteenth-century Vienna would fit into a large New York apartment block; that in a given year the United States Copyright Office registers close to two hundred thousand “works of the performing arts,” from advertising jingles to epic tone poems. Composers and painters now awake into a universe with a nearly infinite range of genres to choose from and rebel against. Mozart did not have to choose an audience or a style. His community was in place. Are the latter-day Mozarts not being born, or are they all around, bumping shoulders with one another, scrabbling for cultural scraps, struggling to be newer than new, their stature inevitably shrinking all the while?

The miler who triumphs in the Olympic Games, who places himself momentarily at the top of the pyramid of all milers, leads a thousand next-best competitors by mere seconds. The gap between best and second-best, or even best and tenth-best, is so slight that a gust of wind or a different running shoe might have accounted for the margin of victory. Where the measuring scale becomes multidimensional and nonlinear, human abilities more readily slide off the scale. The ability to reason, to compute, to manipulate the symbols and rules of logic—this unnatural talent, too, must lie at the very margin, where small differences in raw talent have enormous consequences, where a merely good physicist must stand in awe of Dyson and where Dyson, in turn, stands in awe of Feynman. Merely to divide 158 by 192 presses most human minds to the limit of exertion. To master—as modern particle physicists must—the machinery of group theory and current algebra, of perturbative expansions and non-Abelian gauge theories, of spin statistics and Yang-Mills, is to sustain in one’s mind a fantastic house of cards, at once steely and delicate. To manipulate that framework, and to innovate within it, requires a mental power that nature did not demand of scientists in past centuries. More physicists than ever rise to meet this cerebral challenge. Still, some of them, worrying that the Einsteins and Feynmans are nowhere to be seen, suspect that the geniuses have fled to microbiology or computer science—forgetting momentarily that the individual microbiologists and computer scientists they meet seem no brainier, on the whole, than physicists and mathematicians.

Geniuses change history. That is part of their mythology, and it is the final test, presumably more reliable than the trail of anecdote and peer admiration that brilliant scientists leave behind. Yet the history of science is a history not of individual discovery but of multiple, overlapping, coincidental discovery. All researchers know this in their hearts. It is why they rush to publish any new finding, aware that competitors cannot be far behind. As the sociologist Robert K. Merton has found, the literature of science is strewn with might-have-been genius derailed or forestalled—“those countless footnotes … that announce with chagrin: ‘Since completing this experiment, I find that Woodworth (or Bell or Minot, as the case may be) had arrived at this same conclusion last year, and that Jones did so fully sixty years ago.’” The power of genius may lie, as Merton suggests, in the ability of one person to accomplish what otherwise might have taken dozens. Or perhaps it lies—especially in this exploding, multifarious, information-rich age—in one person’s ability to see his science whole, to assemble, as Newton did, a vast unifying tapestry of knowledge. Feynman himself, as he entered his forties, prepared to undertake this very enterprise: a mustering and a reformulating of all that was known about physics.

Scientists still ask the what if questions. What if Edison had not invented the electric light—how much longer would it have taken? What if Heisenberg had not invented the S matrix? What if Fleming had not discovered penicillin? Or (the king of such questions) what if Einstein had not invented general relativity? “I always find questions like that … odd,” Feynman wrote to a correspondent who posed one. Science tends to be created as it is needed.

“We are not that much smarter than each other,” he said.

Weak Interactions

By the late 1950s and early 1960s, as the discovery of new particles became more commonplace, physicists found it harder to guess what might and might not be possible. The word zoo entered their vocabulary, and their scientific intuition sometimes seemed colored by a kind of aesthetic queasiness. Weisskopf declared at one meeting that it would be a shame if anyone found a particle with double charge. Oppenheimer added that he personally would hate to see a strongly interacting particle with spin greater than one-half. Both men were quickly disappointed. Nature was not so fastidious.

The methods assembled under the label of field theory just a few years before—direct computation of particle interactions, in the face of those still-troubling infinities—fell out of favor with many. The success of quantum electrodynamics did not extend easily to other particle realms. Of the four fundamental forces—electromagnetism; gravity; the strong force binding the atomic nucleus; and the weak force at work in radioactive beta decay and in strange-particle decays—renormalization seemed to work only for electromagnetism. With electromagnetism, the first, simplest Feynman diagrams told most of the story. Mathematically the relative weakness of the force expressed itself in the diminishing importance of more complicated diagrams (for the same reason that the later terms in a series like 1 + n + n2 + … vanish if nis 1/100). With the strong force, the forest of Feynman diagrams made an unendingly large contribution to any calculation. That made real calculations impossible. So where the more esoteric forces were concerned, it seemed impossible to match the success of quantum electrodynamics in making amazingly precise dynamical predictions. Instead, symmetries, conservation laws, and quantum numbers provided abstract principles by which physicists could at least organize the experimentalists’ data. They looked for patterns, organized taxonomies, filled in holes. A diverging branch of mathematical physicists continued to pursue field theory, but most theorists now found it profitable to sift through particle data—the data now arriving in huge volume—looking for general principles. Searching for symmetries meant not tying oneself to the microscopic dynamics of particle behavior. It came to seem almost immoral, or at least silly, for a theorist to write down a specific dynamic or scale.

The understanding of symmetry also became an understanding of symmetry’s imperfections, for, as symmetry laws came to dominate, they also began to break down. One of the most obvious of all symmetries led the way: the symmetry of left and right. Humans seem mostly symmetrical, but not perfectly so. The symmetry is “broken,” as a modern physicist would say, by an off-center heart and liver and by more subtle or superficial differences. We learn to break the symmetry ourselves by internalizing an awareness of the difference between left and right, although sometimes this is not so easy. Feynman himself confessed to a group gathered around the coffee pot in a Caltech laboratory that even now he had to look for the mole on the back of his left hand when he wanted to be sure. As early as his MIT fraternity days he had puzzled over the classic teaser of mirror symmetry: why does a mirror seem to invert left and right but not top and bottom? That is, why are the letters of a book backward but not upside down, and why would Feynman’s double behind the mirror appear to have a mole on his right hand? Was it possible, he liked to ask, to give a symmetrical explanation of what a mirror does—an explanation that treats up-and-down no differently from left-and-right? Many logicians and scientists had debated this conundrum. There were many explanations, some of them correct. Feynman’s was a model of clarity.

Imagine yourself standing before the mirror, he suggested, with one hand pointing east and the other west. Wave the east hand. The mirror image waves its east hand. Its head is up. Its west hand lies to the west. Its feet are down. “Everything’s really all right,” Feynman said. The problem is on the axis running through the mirror. Your nose and the back of your head are reversed: if your nose points north, your double’s nose points south. The problem now is psychological. We think of our image as another person. We cannot imagine ourselves “squashed” back to front, so we imagine ourselves turned left and right, as if we had walked around a pane of glass to face the other way. It is in this psychological turnabout that left and right are switched. It is the same with a book. If the letters are reversed left and right, it is because we turned the book about a vertical axis to face the mirror. We could just as easily turn the book from bottom to top instead, in which case the letters will appear upside down.

Our own asymmetries—our blemishes, hearts, handednesses—arise from contingent choices nature made in the process of building up complicated organisms. A preference for right or left appears in biology all the way down to the level of organic molecules, which can be right- or left-handed. Sugar molecules have this intrinsic corkscrew property. Chemists can make them with either handedness, but bacteria digest only “right-handed” sugar, and that is the kind that sugar beets produce. Earthly sugar beets, that is—for evolution might just as well have chosen a left-handed pathway, just as the industrial revolution might have settled on left-threaded rather than right-threaded screws.

On still smaller scales, at the level of elementary particle interactions, physicists assumed that nature would not distinguish between right and left. It seemed inconceivable that the laws of physics would change with mirror reflection, any more than they change when an experiment is conducted at a different place or a different time. How could anything so featureless as a particle embody the handedness of a corkscrew or a golf club? Right-left symmetry had been built into quantum mechanics in the form of a quantity called parity. If a given event conserved parity, as most physicists consciously or unconsciously assumed it must, then its outcome did not depend on any left-right orientation. Conversely, if nature did have some kind of handedness built into its guts, then an experimenter might be able to find events that did not conserve parity. When Murray Gell-Mann was a graduate student at MIT, a standard problem in one course was to derive the conservation of parity by mathematical logic, transforming coordinates from left-handed to right-handed. Gell-Mann spent a long weekend transforming coordinates back and forth without proving anything. He recalled telling the instructor that the problem was wrong: that the conservation of parity was a physical fact that depended on the structure of a particular theory, not on any inescapable mathematical truth.

Parity became an issue in theorists’ unease about the liveliest experimental problem coming out of the accelerators in 1956: the problem of the theta and the tau, two strange particles (strange in Gell-Mann’s sense). It was typical of the difficulties physicists were having in making taxonomical sense of the jumble of accelerator data. When the theta decayed, a pair of pions appeared. When the tau decayed, it turned into three pions. In other ways, however, the tau and the theta were beginning to look suspiciously similar. Data from cosmic rays and then accelerators made their masses and lifetimes seem indistinguishable. One experimenter had plotted thirteen data points in 1953. By the time the 1956 Rochester conference convened, he had more than six hundred data points, and the theorists were trying to face the obvious: perhaps the tau and the theta were one and the same. The problem was parity. A pair of pions had even parity. A trio of pions had odd parity. Assuming that a particle’s decay conserved parity, a physicist had to believe that the tau and the theta were different. Intuitions were severely tested. Sometime after the Rochester conference ended, Abraham Pais wrote a note to himself: “Be it recorded here that on the train back from Rochester to New York, Professor Yang and the writer each bet Professor Wheeler one dollar that the theta- and tau-meson are distinct particles; and that Professor Wheeler has since collected two dollars.”

Everyone was making bets. An experimenter asked Feynman what odds he would give against an experiment testing for the unthinkable, parity violation, and Feynman was proud later that he had offered a mere fifty to one. He actually raised the question at Rochester, saying that his roommate there, an experimenter named Martin Block, had wondered why parity could not be violated. (Afterward Gell-Mann teased him mercilessly for not having asked the question in his own name.) Someone had joked nervously about considering even wild possibilities with open minds, and the official note taker recorded:

Pursuing the open mind approach, Feynman brought up a question of Block’s: Could it be that the [theta] and [tau] are different parity states of the same particle which has no definite parity, i.e., that parity is not conserved. That is, does nature have a way of defining right- or left-handedness uniquely?

Two young physicists, Chen Ning Yang and Tsung Dao Lee, said they had begun looking into this question without reaching any firm conclusions. So desperately did the participants dislike the idea of parity violation that one scientist proposed yet another unknown particle, this time one that departed the scene with no mass, no charge, and no momentum—just carrying off “some strange space-time transformation properties” like a sanitation worker carting away trash. Gell-Mann rose to suggest that they keep their minds open to the possibility of other, less radical solutions. Discussion continued until, as the note taker put it, “The chairman”—Oppenheimer—“felt that the moment had come to close our minds.”

But in Feynman’s tentative question the answer had emerged. Lee and Yang undertook an investigation of the evidence. For electromagnetic interactions and strong interactions, the rule of parity conservation had a real experimental and theoretical foundation. Without parity conservation, a well-entrenched framework would be torn apart. But that did not seem to be true for weak interactions. They went through an authoritative text on beta decay, recomputing formulas. They examined the recent experimental literature of strange particles. By the summer of 1956 they realized that, as far as the weak force was concerned, parity conservation was a free-floating assumption, bound neither to any experimental result nor to any theoretical rationale. Furthermore, it occurred to them that Gell-Mann’s conception of strangeness offered a precedent: a symmetry that held for the strong force and broke down for the weak. They quickly published a paper formally raising the possibility that parity might not be conserved by weak interactions and proposing experiments to test the question. By the end of the year, a team led by their Columbia colleague Chien Shiung Wu had set one of them up, a delicate matter of monitoring the decay of a radioactive isotope of cobalt in a magnetic field at a temperature close to absolute zero. Given an up and down defined by the alignment of the magnetic coil, the decaying cobalt would either spit out electrons symmetrically to the left and right or would reveal a preference. In Europe, awaiting the results, Pauli joined the wagerers: he wrote Weisskopf, “I do not believe that the Lord is a weak left-hander, and I am ready to bet a very large sum that the experiments will give symmetric results.” Within ten days he knew he was wrong, and within a year Yang and Lee had received one of the quickest Nobel Prizes ever awarded. Although physicists still did not understand it, they appreciated the import of the discovery that nature distinguished right from left in its very core. Other symmetries were immediately implicated—the correspondence between matter and antimatter, and the reversibility of time (if the film of an experiment were run backwards, for example, it might look physically correct except that right would be left and left would be right). As one scientist put it, “We are no longer trying to handle screws in the dark with heavy gloves. We are being handed the screws neatly aligned on a tray, with a little searchlight on each that indicates the direction of its head.”

Feynman made an odd presence at the high-energy physicists’ meetings. He was older than the bright young scientists of Gell-Mann’s generation, younger than the Nobel-wielding senators of Oppenheimer’s. He neither withdrew from the discussions nor dominated them. He showed a piercing interest in the topical issues—as with his initial prodding on the question of parity—but struck younger physicists as detached from the newest ideas, particularly in contrast to Gell-Mann. At the 1957 Rochester conference it occurred to at least one participant that Feynman himself should have applied his theoretical talents to the question he had raised a year earlier, instead of leaving the plum to Yang and Lee. (The same participant noticed a revisionists’ purgatory in the making: theorists from Dirac to Gell-Mann “busy explaining that they personally had never thought parity was anything special,” and experimenters recalling that they had always meant to get around to an experiment like Wu’s.) Publicly, Feynman was as serene as ever. Privately, he agonized over his inability to find the right problem. He wanted to stay clear of the pack. He knew he was not keeping up with even the published work of Gell-Mann and other high-energy physicists, yet he could not bear to sit down with the journals or preprints that arrived daily on his desk and piled up on his shelves and merely read them. Every arriving paper was like a detective novel with the last chapter printed first. He wanted to read just enough to understand the problem; then he wanted to solve it his own way. Almost alone among physicists, he refused to referee papers for journals. He could not bear to rework a problem from start to finish along someone else’s track. (He also knew that when he broke his own rule he could be devastatingly cruel. He summarized one text by writing, “Mr. Beard is very courageous when he gives freely so many references to other books, because if a student ever did look at another book, I am sure he would not return again to continue reading Beard,” and then urged the editor to keep his review confidential—“for Mr. Beard and I are good personal friends.”) His persistently iconoclastic approach to other people’s work offended even theorists whom he meant to compliment. He would admire what they considered a peripheral finding, or insist on what struck them as a cockeyed or baroque alternative viewpoint. Some theorists strived to collaborate with colleagues and to set a tone and an agenda for whole groups. Gell-Mann was one. Feynman seemed to lack that ambition—though a generation of physicists now breathed Feynman diagrams. Still, he was frustrated.

He sometimes confided in his sister, Joan, who had begun a career in science herself, getting a doctorate in solid-state physics at Syracuse University. She was still living in Syracuse, and Feynman visited her when he went to Rochester. He complained to her that he could not work. She reminded him of all the recent ideas that he had shared with her and then refused to pursue long enough to write a paper. You’ve done it again and again, she said. You told me that Block might be right. And you don’t do a damn thing about it. You should write it up, for crying out loud, when you have something like this. She also reminded him that he had mentioned an idea for a universal theory of weak interactions—tying together beta decay and the strange-particle decays based on the weak force—and urged him, finally, to see where it would lead.

In its classic form, beta decay turns a neutron into a proton, throwing off an electron and another particle, a neutrino—massless, chargeless, and hard to detect. Charge is conserved: the neutron has none; the proton carries + 1 and the electron - 1. Analogously, in the meson family, a pion could decay into a muon (like a heavy electron) and a neutrino. A good theory would predict the rates of decay in such processes, as well as the energies of the outgoing particles. There were complications. The spins of the particles had to be reconciled, and for the massless neutrinos, especially, problems of handedness arose in calculating the appropriate spins. So the new understanding of parity violation immediately changed the weak-interaction landscape—for Feynman, for Gell-Mann, and for others.

In sorting the various kinds of particle interactions, theorists had created a classification scheme with five distinct transformations of one wave function into another. In one sense it was a classification of the characteristic algebraic techniques; in another, it was a classification of the types of virtual particles that arose in the interactions, according to their possible spins and parities. As shorthand, physicists used the labels S, T, V, A, and P, for scalar, tensor, vector, axial vector, and pseudoscalar. The different kinds of weak interaction had evident similarities, but this classification scheme posed a problem. As Lee pointed out at the 1957 Rochester meeting, most experiments on beta decay had demonstrated S and T interactions, while the new parity-violation experiments tended to suggest that meson decay involved V and A. Under the circumstances, the same physical laws could hardly be at work.

In reading Lee and Yang’s preprint for the meeting—Joan had ordered him, for once, to sit down like a student and go through it step by step—Feynman saw an alternative way of formulating the violation of parity. Lee and Yang described a restriction on the spin of the neutrino. He liked the idea enough to mention it from the audience during five minutes cadged from another speaker. He went far back into the origins of quantum mechanics—back not only to the Dirac equation itself but beyond, to the Klein-Gordon equation that he and Welton had manufactured when they were MIT undergraduates. Using path integrals, he moved forward again, deriving—or “discovering”—an equation slightly different from Dirac’s. It was simpler: a two-component equation, where Dirac’s had four components. “Now I asked this question,” Feynman said:

Suppose that historically [my equation] had been discovered before the Dirac equation? It has absolutely the same consequences as the Dirac equation. It can be used with diagrams the same way.

The diagrams for beta decay, of course, added a neutrino field interacting with the electron field. When Feynman made the necessary change to his equation, he found:

Of course I can’t do that because this term is parity unsymmetric. But——beta decay is not parity symmetric, so it’s now possible.

There were two difficulties. One was that he came out with the opposite sign for the spin: his neutrino would have to spin in the opposite direction from Lee and Yang’s prediction. The other was that the coupling in his formulation would have to be V and A, instead of the S and T that everyone knew was correct.

Gell-Mann, meanwhile, had also thought about the problem of creating a theory for weak interactions. Nor were Feynman and Gell-Mann alone: Robert Marshak, who had put forward the original two-meson idea at the Shelter Island conference in 1947, was also leaning toward V and A with a younger physicist, E. C. G. Sudarshan. That summer, with Feynman traveling in Brazil, Marshak and Sudarshan met with Gell-Mann in California and described their approach.

Feynman returned at the end of the summer determined, for once, to catch up with the experimental situation and follow his weak-interaction idea through to the end. He visited Wu’s laboratory at Columbia, and he asked Caltech experimenters to bring him up to date. The data seemed a shambles—contradictions everywhere. One of the Caltech physicists said that Gell-Mann even thought the crucial coupling could be V rather than S. That, as Feynman often recalled afterward, released a trigger in his mind.

I flew out of the chair at that moment and said, “Then I understand everything. I understand everything and I’ll explain it to you tomorrow morning.”

They thought when I said that, I’m making a joke… . But I didn’t make a joke. The release from the tyranny of thinking it was S and T was all I needed, because I had a theory in which if V and Awere possible, V and A were right, because it was a neat thing and it was pretty.

Within days he had drafted a paper. Gell-Mann, however, decided that he should write a paper, too. As he saw it, he had his own reasons for focusing on V and A. He wanted the theory to be universal. Electromagnetism depended on vector coupling, and the strange particles favored V and A. He was unhappy that Feynman seemed to be thoughtlessly dismissing his ideas.

Before the tension between them rose higher, their department head, Robert Bacher, stepped in and asked them to write a joint paper. He preferred not to see rival versions of the same discovery coming out of Caltech’s physics group. Colleagues strained to overhear Feynman and Gell-Mann in the corridors or at a cafeteria table, engrossed in their oral collaboration. They stimulated each other despite the characteristic differences in their language: Feynman offering what sounded like you take this and it zaps through here and you come out and pull this together like that, Gell-Mann responding with you substitute there and there and integrate like so… . Their article reached the Physical Review in September, days before Marshak presented his and Sudarshan’s similar theory at a conference in Padua, Italy. Feynman and Gell-Mann’s theory went further in several influential respects. It proposed a bold extension of the underlying principles beyond beta decay to other classes of particle interactions; it would be years before experiment fully caught up, showing how prescient the two men had been. It also introduced the idea that a new kind of current—analogous to electrical current, a measure of the flow of charge—should be conserved; new extensions of the concept of current became a central tool of high-energy physics.

Feynman tended to recall that they had written the paper together. Gell-Mann sometimes disdained it, complaining particularly about the two-component formalism—a ghastly notation, he felt. It did bear Feynman’s stamp. He was applying a formulation of quantum electrodynamics that went back to his first paper on path integrals in 1948; Gell-Mann allowed him to remark fondly, “One of the authors has always had a predilection for this equation.” Yet it could hardly have been Feynman who wrote that their approach to parity violation “has a certain amount of theoretical raison d’être.” Evident, too, was Gell-Mann’s drive to make the theory as unifying and forward-looking as possible. The discovery was esoteric compared to other milestones of modern physics. If Feynman, Gell-Mann, Marshak, or Sudarshan had not made it in 1957, others would have soon after. Yet to Feynman it was as pure an achievement as any in his career: the unveiling of a law of nature. His model had always been Dirac’s magical discovery of an equation for the electron. In a sense Feynman had discovered an equation for the neutrino. “There was a moment when I knew how nature worked,” he said. “It had elegance and beauty. The goddamn thing was gleaming.” To other physicists, “Theory of the Fermi Interaction,” barely six pages long, shone like a beacon in the literature. It seemed to announce the beginning of a powerful collaboration between two great and complementary minds. They took a distinctive kind of theoretical high ground, repeatedly speaking of universality, of simplicity, of the preservation of symmetries, of broad future applications. They worked from general principles rather than particular calculations of dynamics. They made clear predictions about new kinds of particle decay. They listed specific experiments that contradicted their theory and declared that the experiments must therefore be wrong. Nothing could have more strikingly declared the supremacy of the theorists.

Toward a Domestic Life

The two-piece “bikini” bathing suit, named after the tiny Pacific atoll that was blasted by atomic and hydrogen bombs through the forties and fifties, had not yet taken over the beaches of the United States in 1958, but Feynman saw one, blue, on the sand of Genève-Plage, and laid his beach towel down nearby. He was visiting Geneva for a United Nations conference on the peaceful uses of atomic energy. He was preparing to give a summary talk in his own name and Gell-Mann’s, telling the assembly:

We are well aware of the fragility and incompleteness of our present knowledge and of the manifold of speculative possibilities… . What is the significance or the pattern behind all these interrelated symmetries, partial symmetries, and asymmetries?

The yearly Rochester conference had also changed venue for the occasion, and he discussed the weak-interaction theory, impressing listeners with the body language he used to demonstrate the appropriate spins and handednesses. He had just turned forty. It was spring, and the young woman in the blue bikini volunteered that Lake Geneva was cold. “You speak English!” he said. She was Gweneth Howarth, a native of a village in Yorkshire, England. She had left home to see Europe by working as an au pair. That evening he took her to a nightclub.

The violation of parity had reached newspapers and magazines briefly. For readers who looked to science for a general understanding of the nature of the universe, the fall of left-right symmetry may have been the last genuinely meaningful lesson to emerge from high-energy physics, circumscribed though it was in the domain of certain very short-lived particle interactions. By contrast, though the universal theory of weak interactions commandeered the attention of theorists and experimenters a year later, the replacement of S and T with V and A made no ripple in the cultural consciousness. By then the American public was busy anyway, assimilating the most shocking scientific development of the 1950s, the piece of news establishing once again in the public mind the truism that science is power.

The beachball-sized aluminum sphere called Sputnik began orbiting the earth on October 4, 1957. Its unexpected presence overhead and the insouciant beep-beep-beep played again and again on American radio and television broadcasts set off a wave of anxiety like nothing since the atomic bomb itself. (Feynman arrived at a picnic that evening in the biologist Max Delbrück’s backyard with a small gray radio receiver that looked as if he had built it himself. He called for an extension cord, tuned the receiver quickly, held up a finger to demand silence, and grinned as the beeps played out over the crowd.) “Red Moon over U.S.,” said Time magazine, immediately announcing “a new era in history” and “a grim new chapter in the cold war.” Newsweek called it “The Red Conquest”—with “all the mastery that it implies in the affairs of men on earth.” Why had the United States established no comparable space program? A worried-looking President Eisenhower said at a news conference, “Well, let’s get this straight. I am not a scientist.” The director of the American Institute of Physics seized the occasion to say that unless his country’s science education caught up with the Soviet Union’s, “our way of life is doomed.” That message was heard: Sputnik produced a rapid new commitment to the teaching of science. Magazines focused new attention on American physicists. Among the younger generation, Time singled out Feynman—

Curly-haired and handsome, he shuns neckties and coats, is an enormously dedicated adventurer … became fascinated with samba rhythms … playing bongo drums, breaking codes, picking locks …

and Gell-Mann—

he formulated the “Strangeness Theory,” i.e. assigned physical meanings to the behavior of newly discovered particles. At CalTech Gell-Mann works closely with Feynman on weak couplings. At the blackboard the two explode with ideas like sparks flying from a grindstone, alternately slap their foreheads at each other’s simplifications, quibble over the niceties.

But the physicist who received most of the public’s attention that fall was Edward Teller. He was in tune with the cold war. Sputnik led him to declare—though there was evidence to the contrary—“Scientific and technical leadership is slipping from our hands.” A direct Soviet attack on the United States was possible, but he saw an even greater threat. “I do not think this is the most probable way in which they will defeat us,” he said. He predicted that the Soviet Union would gain a broad technological dominance over the free world. “They will advance so fast in science and leave us so far behind that their way of doing things will be the way, and there will be nothing we can do about it.”

With the winter’s excitement barely waning—the Reader’s Digest had now faced into the wind with an article titled “No Time for Hysteria”—a State Department official let Caltech know that the department would appreciate a presentation at the Geneva conference in the name of both Feynman and Gell-Mann, to balance the expected Soviet scientific presence there. Feynman acquiesced, although the mixing of propaganda and science disturbed him.

He declined to let the State Department make his hotel reservation; he found a walk-up room in an establishment called, in English, Hotel City. It reminded him of the flophouses he had known in Albuquerque and on his cross-country trip with Freeman Dyson. He had hoped to bring a woman with whom he had been having a sporadic and tempestuous yearlong love affair—the wife of a research fellow. She had accompanied him on a trip the summer before, when he was working on weak interactions. Now she agreed to meet him afterward in England but refused to come to Geneva. Instead, he met Gweneth Howarth on the beach.

She told him she was making her way around the world. She was twenty-four years old, the daughter of a jeweler in a town called Ripponden. She had worked as a librarian for a salary of three pounds weekly and then as a yarn tester at a cotton mill before deciding life in the backwaters of Yorkshire was too dull. She let Feynman know that she had two current boyfriends, a semiprofessional miler from Zurich, always in training, and a German optician from Saarbrücken. He immediately invited her to come to California and work for him. He needed a maid, he said. He would sponsor her with the immigration authorities and pay her twenty dollars a week. It seemed to her that he was not behaving like a forty-year-old; nor like other Americans she had met. She said she would consider it, and an unusual courtship began.

“I’ve decided to stay here after all,” she wrote him that fall. One of the boyfriends, Johann, had decided to marry her—out of jealousy, she suspected—

so you see what a good turn you did for me… . we talked for hours and hours, planning our life together. We shall probably start married life living in one room… . Were you really expecting me to come? … You’ll just have to get married again, or find a nice solid middle-aged housekeeper so people won’t gossip.

His love affairs were going badly, meanwhile. That same week a letter arrived from the other woman, making it clear that their relationship was over. She demanded money—five hundred dollars—“I will be frank, the chances of your getting it all back within a year are nil.” She had asked for money before, saying that she needed it for an abortion, but now she said that that had been a ruse. His money had actually gone for furniture and house painting.

You were too much of the “playboy.” But I was both embarrassed & intrigued by the effects that your girl friends had on you when they called you in my presence. Sometimes you left the phone, shaking & foaming at the mouth… . I recognized a baseness in you and was frightened that you took my love and affection for you cheaply, and so I wanted to compensate against that horrible feeling.

She knew too much about the women he had been seeing since his divorce. She named four of them and described an anonymous note that had come addressed to “Occupant”:

Dirty Dick, Filthy Fucking Feynman dates you. He will never marry you. Tell him he has made you pregnant. You’ll make a quick $300-$500.

She had been devastated by nasty physicist-gossip she had overheard about Feynman and his women, Feynman and “the pox.” He should get married, she said.

The baseness you talk of is due to the fact you aren’t married. You try to sublimate your desires by attending Burlesque Shows, Night Clubs, etc. These are fun for the healthy, but only an escape for the dissatisfied. I know this, because last year you were content in Rio, & as a result produced Beta Decay… .

Find yourself a real companion, someone you can really love & respect. Then capture love whilst it is fresh & spontaneous… .

At some point she had walked off with the gold medal he had received with the Einstein Award. She still had it, she reminded him.

Feynman implored Gweneth Howarth to reconsider. By November, as it happened, she and Johann were no longer on speaking terms and she had begun the immigration paperwork through the United States Consulate in Zurich. He consulted a lawyer, who warned that there were dangers in transporting women for immoral purposes and advised him to find a third-party employer; a Caltech friend, Matthew Sands, agreed to lend his name on the required documents. Feynman calculated fares (more than a year’s salary for a Yorkshire librarian, she noticed): $394.10 to Los Angeles; or $290.10 to New York and then $79.04 including tax for a bus from New York to Los Angeles.

She was excited but unsure. “You’ll write & tell me if you decide to get married again, or if there is any other reason why I should not come?” She wanted him to realize she had other possibilities—Armando, whom she met skiing, or a fellow who had been watching her at language class (“he walked part of the way home with me … I’d like it to be a platonic friendship, but I don’t suppose he will want it like that …”) and yet there were always hints of the domestic future Feynman so craved now—she was caring for “a beautiful baby now, I wish I could have one exactly like him.” A new friend, Engelbert, was buying skis for her; meanwhile she could now cook pheasant, chicken, goose, and hare with the appropriate sauces (“I’m improving, am I not?”). Feynman kept hearing from the other woman, too. She was telling her husband everything; they had left California for the East Coast. She wanted more money. She felt used. He let her know how angry he was. She told him, “altho’ you are clever at your own special work, you are very dim at human relationships.” She assured him that his Einstein Award medal was “safe”; also his copy of the Rubáiyát of Omar Khayyám, with drawings that had been carefully colored, so long ago, by Arline.

He begged her to come see him again. “I only mentioned my inner feelings for revenge, etc. to explain why it would be hard to guarantee you something that you asked,” he wrote. He still wanted to marry her.

I know where the right is—but emotions, like anger and hate and vengeance etc. are like a bunch of snakes in a barrel—with reason and good heart as a lid… . it is frightening and uncertain. Worth a good try tho.

She refused, despite the warm memories that now came back to her: building a sandcastle at the beach, surrounded by a mob of small boys; camping under the stars at Joshua Tree National Monument, where Feynman had tinkered delightedly with his gleaming green Coleman stove. On a wet Sunday night he had shown her a battered suitcase with all of Arline’s letters and photographs. Once in a flash of anger he had called her a prostitute—a cruel rhetorical weapon he had used before. “And,” she wrote, “I did enjoy my boss & my work.”

Her husband’s memories were not so warm. At a party he listened to someone telling a story about Feynman and blurted out that he knew a better one—but stopped. A few days later he wrote Feynman a formal letter demanding compensation. “You have taken callous & unscrupulous advantage of your position & salary to seduce an impressionable girl away from her husband,” he wrote. Could Feynman not remember the harder times of his own first marriage? “You alienated my wife’s affections. You flattered her with your attentions and your gifts. You made clandestine plans for exciting vacations… . I think you should pay for indulging your selfish pleasure.” He demanded $1,250. Feynman refused.

Gweneth Howarth was reporting that Engelbert had brought cognac and chocolate to celebrate her twenty-fifth birthday; she decided to improve her shorthand and typing (“You do need someone to look after you, don’t you?”). Feynman sent the consulate in Zurich an affidavit vouching for her (“she is an intelligent girl with a fine personality and is an excellent cook and domestic servant”) and guaranteeing to undertake her financial support if necessary. Gweneth thanked him, mentioning that she had now met an Arab boy, beautifully polite, but he had started to make love to her. She had to avoid Engelbert because she could not hide a love bite on her neck. She was making her way through the immigration paperwork: pages of questions designed to ensure that she was not a Communist and then—infuriating her—questions about whether she was a woman of good character where sex was concerned. From what moral high ground—and with what bureaucratic logic—did the American authorities require her to swear that she was neither a prostitute nor an adulterer?

Feynman, meanwhile, tried to placate his former lover’s husband: “… forgive her and make her happy… . your love will be deeper for the forgiveness and greater because you each know how you have suffered.”

“Good thought,” the husband retorted, “but why don’t you apply it to yourself since you have enjoyed her for so long… . Don’t give me the story of your parents’ teachings, society etc. for I don’t go for that.” He engaged attorneys, who sent threatening letters on his behalf. But Feynman’s attorneys advised him not to settle, guessing that the matter would fade away on its own. The last word belonged to his lover.

I hope you are happy with your maid. Now you will always have your sex laid on. I think I begin to understand what you mean by a “good relationship.” … But I can’t understand why you are so afraid of marriage? Is it too dull for you? I thought think sex without love wasn’t isn’t very satisfying, that the satisfaction only came by both parties desiring the happiness of the other, given in complete faith, truth & love without reserve. Anything short of that, I thought, was lust or fucking like animals.—Perhaps that is why you have such a large turn-over with your women.

A half-year later she finally returned his medal.

He surprised Gweneth with his excitement at the news that her visa had finally cleared the consulate. “Well, at last!” he wrote. “I was overjoyed to hear that you are coming at last.”

I need you more than ever… . I’m looking forward to being much happier… . I have to take care of you too, you know. As soon as you arrive here you are a responsibility of mine to see you are happy & not scared.

He had pared back the domestic side of daily life in minimalist fashion, striving for the least drain on his consciousness. When Gweneth Howarth finally arrived in the summer of 1959 she found a man with five identical pairs of shoes, a set of dark blue serge suits, and white shirts that he wore open at the neck. (She surreptitiously introduced colored shirts in deliberate stages, beginning with the palest of pastels.) He owned neither a radio nor a television. He carried pens in a standard slip-in shirt-pocket protector. He taught himself to keep keys, tickets, and change always in the same pocket so that he would never have to give them an instant’s thought.

At first he kept her presence secret from all but a few close colleagues. She took charge of the household as promised. He reveled in his pretty English domestic servant. He taught her to drive and experimented with letting her drive him about chauffeur-style, while he sat in the rear seat. She worried that he thought she was fluffy-minded; in fact he discovered that she was cool and independent. She made a point of finding men to date—a Beverly Hills stockbroker replaced the German optician—but Feynman’s friends gradually realized that their arrangement was turning romantic. They would appear at parties together and then make a show of departing separately, as though they had different places to go. Sometime in the next spring he realized how contented he felt, but he was not sure how to make the next decision. He marked a date on the calendar several weeks ahead and told himself that if his feelings had not changed by then, he would ask Gweneth to marry him. As the day approached, he could hardly wait. The evening before, without telling her why, he kept her awake until midnight. Then he proposed. They were married on September 24, 1960, at Pasadena’s grand Huntington Hotel. He hid his car so that no one could tie tin cans to the fenders, and moments after the reception he ran out of gasoline on the Pasadena Freeway. He told Gweneth cheerfully: So this is how we’re starting life. Murray Gell-Mann, who had married an Englishwoman he met at the Institute for Advanced Study several years before, thought Feynman was playing catch-up—now he, too, had acquired an English wife and a small brown dog.

The Feynmans and the Gell-Manns bought houses not far from each other in Altadena, north of the campus, nestled in the high hills that cup the smog drifting up from Los Angeles. Richard spent long hours teaching the dog, Kiwi, increasingly circuitous tricks; Feynman’s mother, who had moved out to Pasadena to be near her son, made droll remarks about what a child would be up against. Gweneth began a garden with citrus scents and exotic colors that could never have survived a Yorkshire winter. In 1962 a son, Carl, was born; six years later they adopted a daughter, Michelle. It was instantly clear to Richard’s friends how much he had wanted children. At first Murray and his wife, Margaret, visited from time to time, and the friendship was never warmer. An image lodged in Gell-Mann’s memory of his friend pitching wads of newspaper into the fireplace for kindling, one after another—and making an ebullient game of it, as he made a game of every mundane gesture. The dog bounded here and there at his command, and he called out happily to Gweneth, and Murray felt magic in his presence.

From QED to Genetics

“Hello, my sweetheart,

“Murray and I kept each other awake arguing until we could stand it no longer. We woke up over Greenland …”

They were off to Brussels together for a conference, partly nostalgic, on “the present state of quantum electrodynamics.” Dirac was there, and Feynman spoke once again with his old hero—Dirac still wholly unreconciled to the renormalization program for evading the infinities that had plagued his old theory. Renormalization seemed an ugly gimmick, an arbitrary and unphysical device for merely discarding inconvenient quantities in one’s equations. To most physicists Dirac’s qualms sounded like the intolerance of the old in the face of new ideas—in this case ideas that succeeded where Dirac’s own theory had broken down. He reminded them of Einstein, with his famous crotchety unwillingness to accept quantum mechanics, and like Einstein he could hardly be dismissed. Honest physicists at least understood his qualms, even if they attributed them, ultimately, to a generational hardening of the intuitions. Age was no friend of the physicist. Wisdom counted for nothing. Feynman was acutely and painfully aware of the truth expressed in a ditty sometimes attributed to Dirac himself; it appeared from time to time, over the years, on Caltech office doors:

Age is, of course, a fever chill
That every physicist must fear.
He’s better dead than living still
When once he’s past his thirtieth year.

Feynman also sympathized with Dirac’s qualms about renormalization, more so than any of his coinventors of the modern methods. Quantum electrodynamics had become a singular triumph of theoretical physics. The computations that had taken Feynman and Schwinger hours or weeks to accomplish in their first and second approximations could now be extended to many deeper levels of accuracy, using electronic computers and hundreds of Feynman diagrams to organize the work. Some theorists and their graduate students spent years on these calculations. They added and subtracted hundreds of terms, deeper and deeper into infinite series. It struck some of them as bizarrely unsatisfying work: some of the terms were enormous, positive or negative, compared to the final result. Yet presumably they would cancel out in the end, leaving a small, finite number. The mathematical status of such computation remained uneasy. It was not mathematically certain that the calculations would converge. Yet for practical calculations in quantum electrodynamics they always seemed to, and when the increasingly precise results were compared with the results of increasingly sensitive experiments, they matched. To convey a sense of how “delicately” experiment and theory agreed, Feynman would say it was like measuring the distance from New York to Los Angeles to within the thickness of a single hair. Yet the unphysical nature of the computing process troubled him, the corrections upon corrections with no sense of whether the next correction must be large or small. “We have been computing terms like a blind man exploring a new room,” he said in his keynote talk in Brussels.

Other theorists, meanwhile, had begun to use the very concept of “renormalizability” as a way of distinguishing between possible theories for the esoteric particles to which quantum electrodynamics did not apply. Dyson had first recognized that it might be fruitful to think of renormalizability this way, as a criterion for judgment. A renormalizable theory was one by which, practically speaking, calculations could be made. “Note the cunning of reason at work,” said the physicist and historian Silvan S. Schweber. “The divergences that had previously been considered a disastrous liability now became a valuable asset.” Gell-Mann and younger theorists applied the notion with real success. “We very much need a guiding principle like renormalizability to help us pick the quantum field theory of the real world out of the infinite variety of conceivable quantum field theories,” said Steven Weinberg years later—recognizing, however, that he was begging the question of why? Why should the correct theories be the computable ones? Why should nature make matters easy for human physicists? Feynman himself remained nearly as uncomfortable as Dirac. He continued to say that renormalization was “dippy” and “a shell game” and “hocus-pocus.”

By the 1960s he seemed to be withdrawing from the most esoteric frontiers of high-energy physics. Quantum electrodynamics had achieved the quiet stature of a solved problem. As a practical theory it had entered applied, solid-state fields like electrical engineering, where, for example, quantum mechanics gave rise to the maser, a device for creating intense beams of coherent radiation, and its successor, the laser. Feynman drifted into the theory of masers for a while, using his path integral methods to lay some of the foundation. He had also worked persistently on another solid state problem, the problem of the so-called polaron, an electron moving through a crystal lattice. The electron distorts the lattice and interacts with its own cloud of distortion, creating, as Feynman realized, a kind of case study for examining the interaction of a particle with its field. Again his diagrams and path integrals found fertile ground. Yet this was minor work, not the special outpouring of someone already regarded as a legend (though each fall, it seemed, younger men won the Nobel Prize).

He could not find the right problem to work on. His Caltech salary passed the twenty-thousand-dollar mark—he was the highest paid member of the faculty. He started telling people jovially that that was a lot of money to be paid for theoretical physics; it was time to do some real work. He had a sabbatical year coming. He did not want to travel. His friend Max Delbrück, himself a physicist turned geneticist, was always trying to lure physicists into his group at Caltech, saying that the interesting questions now lay in molecular biology. Feynman told himself that he would go into a different field instead of a different country.

In biology the theorists and the laboratory workers were still largely one and the same. Feynman began in the summer of 1960 by learning how to grow strains of bacteria on plates, how to suck drops of solution into pipettes, how to count bacteriophages—viruses that infect bacteria—and how to detect mutations. He planned experiments at first to teach himself the techniques. Much of Delbrück’s laboratory devoted itself to the genetics of such microcreatures: tiny, efficient DNA-replicating machines. The most popular virus when Feynman arrived in the upper basement of Church Hall was a bacteriophage called T4, which grew on the common strain of E. coli bacteria.

Less than a decade had passed since James Watson and Francis Crick had elucidated the structure of DNA, the molecule that carried the genetic code. Code was one word for this storing of information; geneticists also thought in terms of maps and blueprints, printed text and recording tape—the mechanics were far from clear. Mutations were known to be changes in the DNA sequence, but no one understood how a developing organism actually “read” the altered map, text, or tape. Was there a biological copying, splicing, folding? Feynman began to feel at home in the basement laboratory. He took comfort from the knowledge that everything around was made of matter. He felt well acquainted with the essence of evaluating experiments—as he said, “understanding when a thing is really known and when it is not really known.” He could see at once how the centrifuge worked and how ultraviolet absorption would show how much DNA remained in a test tube. Biology was messier—things grew and wiggled, and he found it difficult to repeat experiments as exactly as he wished.

He focused on a particular mutation of the T4 virus called rII. This mutant had the useful quality of growing abundantly on one strain of the E. coli bacteria, strain B, while not growing at all on strain K. So a researcher could infect strain K bacteria with the mutants and watch for signs of T4. If any appeared, it must mean that something had happened to the rII mutation—presumably, it had reverted back to its original form. Such “backmutation” was relatively rare, but when it happened, giving the virus the ability to grow again in the K bacteria, it could be detected with extreme sensitivity, rates as low as one in a billion. Feynman compared finding a T4 backmutation to finding one man in China with elephant ears, purple spots, and no left leg. He collected them, isolated them, and injected them back into bacteria of strain B to see how they would grow.

Odd-looking plaques appeared. Among the normal, backmutated T4, he began to see phages that did not grow as they should have. He called them “idiot r’s.” He could only guess what might be happening at the level of the DNA itself to create the idiot r’s. He saw two possibilities: the site of the rII mutation in the DNA strand might have undergone a second, further mutation. Or a second mutation might have occurred at a different site, somehow acting to partially cancel the effect of the first mutation.

Tools for directly examining the genetic sequence, letter by letter, base pair by base pair, did not exist. But by painstakingly crossing the idiot r’s with the original virus, Feynman was able to show that his second guess was correct: two mutations, situated close to each other on the gene, were interacting. Furthermore, he showed that the second mutation had the same character as the first; it was another rII mutation. He had discovered a new phenomenon, mutations that suppressed each other within the same gene. Friends of his in the laboratory called these “Feyntrons” and tried to persuade him to write up his work for publication. Elsewhere, discovered independently, the phenomenon came to be called intragenic suppression. Feynman could not explain it. The Caltech biologists had no clear model for understanding how the genetic code was read, how the information encoded in DNA actually transformed itself into working proteins and more complex organisms. And Feynman’s time as a geneticist had come to an end. He desperately wanted to return to physics. When he was not grinding microsomes, he had been working more and more intently on a quantum theory of gravity.

Without realizing it, Feynman had come to the brink of the next great breakthrough in modern genetics. The specialists had an advantage after all: a year later, Francis Crick’s team at Cambridge, England, used the discovery of intragenic suppression as the touchstone for an explanation of how the genetic code was read. They guessed, correctly, that the mutations actually added or deleted a unit of DNA, thus shifting the message back or forward. One mutation threw the message temporarily out of phase; the next mutation put it back in phase. This interpretation suggested—or perhaps Crick already had it in mind—one of the simplest, yet strangest, mechanical models for genetic decoding: that the message of the gene is read in linear fashion, one base pair after another, from beginning to end. By 1966 Crick was declaring, “The story of the genetic code is now essentially complete.”

Ghosts and Worms

The problem of gravity had the finest pedigree—it came in a direct line of descent from Einstein’s greatest work—yet it lay outside the mainstream of high-energy theoretical physics in the early 1960s. As the general theory of relativity neared its fiftieth anniversary, some relativists and mathematical physicists continued to struggle with the natural problem of trying to create a quantum theory of gravitation—to quantize the gravitational field, as the fields associated with other forces had been quantized. It was difficult, involuted work. A quantum field theory of Einsteinian gravitation meant, as Gell-Mann said, a “quantum mechanical smearing of space-time” itself. No experimental evidence demanded that gravity must be quantized, but physicists did not wish to imagine a world in which some fields obeyed the laws of quantum mechanics and others did not.

The difficulty, from an experimentalist’s perspective, was that gravity was so weak compared to the other forces. A bare handful of electrons can create a palpable electromagnetic force, while it takes a mass as great as the earth to create the gravity that draws a leaf from a tree. The orders of magnitude separating these forces strain the imagination and cause immense mathematical difficulties for theorists trying to reconcile them. The difference is 1042, a number that defied even Feynman’s ability to find illustrative analogies. “The gravitational force is weak,” he said at one conference, introducing his work on quantizing gravity. “In fact, it’s damned weak.” At that instant a loudspeaker demonically broke loose from the ceiling and crashed to the floor. Feynman barely hesitated: “Weak—but not negligible.”

He had begun with Einstein’s theory and simply started calculating, as he had done in electrodynamics. He pushed his way into different corners of the problem in original fashion. The late 1950s were a time when relativity specialists were confused about the nature of gravitational radiation, and the high levels of mathematical rigor they demanded were blocking them from the right approximations. To Feynman it seemed straightforward that gravitational waves were real. Once again he began with a palpable physical intuition and charged forward. He found answers—decisive, he believed—to questions that relativists argued about: Do gravity waves carry energy? (Yes, he showed.) Can gravity waves be detected by small-scale measurements inside the wavelength? (No, he argued. “Only beyond the wave length can a clear proof of waves be found,” he wrote Victor Weisskopf when he heard that his old friend was interested in his gravity work. “I have not seen any plans for any such experiments, except by crackpots.”) For the sake of argument, at least, he refused to abandon altogether the possibility that gravity could not be quantized after all. “Maybe gravity is a way that quantum mechanics fails at large distances. Isn’t it interesting to live in our time and have such wonderful puzzles to work on?” He wrote down Feynman diagrams and computed integrals, and he could see that he was producing answers that could not be right. The probabilities did not add up to one. Yet he realized—with a combination of physical and diagrammatic intuition—that he could make up the deficits all at once if he resorted to a gimmick. He had to add “ghosts,” fictitious particles that would circle around the Feynman diagrams, appearing just long enough to form loops and then vanishing once more into mathematical oblivion. It was a curious idea, but it worked, and he reported it in Warsaw, Poland, at a conference on gravitation in July 1962.

The subject was on the eve of a rebirth, when discoveries from astrophysicists and theories from relativists would come together in a shower of black holes, white dwarfs, quasars, and other cosmological treasures. Feynman himself continued his gravitational work for years. He applied the gauge-symmetry machinery known as Yang-Mills. He made an influential contribution without ever reaching a complete enough theory to publish whole. For the moment, he found no more joy in a gathering of relativists than in the conclaves on high-energy physics he was temporarily fleeing. One of the speakers began seriously: “Since 1916 we have had a slow, rather painful accumulation of minute technical improvements… . I think that the attempt to continue obtaining such minute improvements constitutes a legitimate and fascinating part of mathematical physics. If something really exciting turns up, fine… .” The American physicists mingled uneasily with their Russian counterparts. They teased each other about searching their rooms for microphones; Feynman actually took apart his telephone at the Grand Hotel and decided that if it contained no bugs the Poles were wasting wire. He was overheard during a break baiting one of the Russians: “What have you ever done in physics, Ivanenko?”

“I’ve written a book with Sokolov.”

“How do I know what you contributed to it? Ivanenko, what is the integral of e to the minus x squared from minus to plus infinity?” Silence. “Ivanenko, what is one and one?” Feynman was dismayed by the work offered up. His own presentation drew little immediate notice, though his “ghosts,” extended by other theorists, later became crucial to modern theory. “I am learning nothing,” he wrote home in frustration, and he gave Gweneth a scathing taxonomy of pretentious science:

The “work” is always: (1) completely un-understandable, (2) vague and indefinite, (3) something correct that is obvious and self-evident, worked out by a long and difficult analysis, and presented as an important discovery, or (4) a claim based on the stupidity of the author that some obvious and correct fact, accepted and checked for years is, in fact, false (these are the worst: no argument will convince the idiot), (5) an attempt to do something, probably impossible, but certainly of no utility, which, it is finally revealed at the end, fails or (6) just plain wrong. There is a great deal of “activity in the field” these days, but this “activity” is mainly in showing that the previous “activity” of somebody else resulted in an error or in nothing useful or in something promising.

He never had liked crowds in science. “It is like a lot of worms trying to get out of a bottle by crawling all over each other.”

Dissatisfied though Feynman remained, his Warsaw talk marked the beginning of a turn toward his path integrals as a fundamental approach to the deepest of cosmological issues. Neither he nor other theorists had relied on this viewpoint in the high-energy physics of the late 1950s. Much later, however, some physicists applied path integrals to the very structure of space-time. They sought to unify its conceivable topologies by, in a sense, summing over all possible universes. Gell-Mann himself speculated that Feynman’s path integrals might prove to be more than a method, more than an equivalent alternative formulation: “the real foundation of quantum mechanics and thus of physical theory.”

Room at the Bottom

So little of modern physics seemed dedicated to the world of human scales. High-energy theorists had skipped far down a ladder of sizes, past the merely microscopic into a realm of the unimaginably small and short-lived. “Miniaturization” was a catchword of the day, but tininess meant something more modest to engineers and manufacturers than to particle physicists. The transistor, invented just over a decade before at the Bell Telephone Laboratories, was becoming a commodity. Transistors meant radios, battery-powered, with brittle plastic casings, small enough to fit in one’s hand. Researchers were beginning to consider ways of further reducing suitcase-sized devices like tape recorders. Electronic computers that had filled large rooms could now be squeezed into cabinets barely larger than an automobile. It occurred to Feynman that engineers had barely begun to imagine the possibilities. “There is a device on the market, they tell me,” he said at the end of 1959, when the American Physical Society held its annual meeting at Caltech, “by which you can write the Lord’s Prayer on the head of a pin. But that’s nothing… .” On toward the atom, he urged them. “It is a staggeringly small world that is below.”

That same pinhead could hold the twenty-four volumes of the Encyclopaedia Britannica, pictures and all, if the encyclopedia were reduced 25,000 times in each direction. A modest reduction, considering that the barely visible dots making up a halftone photoengraving would still contain a thousand or so atoms. For writing and reading this tiny Britannica, he proposed engineering techniques within the limits of contemporary technology: reversing the lenses of an electron microscope, for example, and focusing a beam of ions to a small spot. At this scale, the world’s entire store of book knowledge could be carried about in a small pamphlet. But direct reduction would be crude, he continued. Telephones and computers had given rise to a new way of thinking about information, and in terms of raw information—allowing six or seven “bits” per letter and a generous one hundred atoms per bit—all the world’s books could be written in a cube no larger than a speck of dust. His audience, unaccustomed to lectures of this kind at American Physical Society meetings, was enthralled. “Don’t tell me about microfilm!” Feynman declared.

He had several reasons for thinking about the mechanics of the atomic world. Although he did not say so, he had been pondering the second law of thermodynamics and the relationship between entropy and information; at atomic scales came the threshold where his calculations and thought experiments took place. The new genetics also brought such issues to the surface. He talked about DNA (fifty atoms per bit of information) and about the capacity of living organisms to build tiny machinery, not just for information storage but for manipulation and manufacturing. He talked about computers: given millions of times more power, they would not just calculate faster but would reveal qualitatively different abilities, such as the ability to make judgments. “There is nothing I can see in the physical laws that says the computer elements cannot be made enormously smaller than they are now,” he said. He talked about problems of lubrication, and he talked about the realm where quantum-mechanical laws would take over. He envisioned machines that would make smaller machines, each of which would make machines that were smaller still. “It doesn’t cost anything for materials, you see. So I want to build a billion tiny factories, models of each other, which are manufacturing simultaneously, drilling holes, stamping parts, and so on.” He concluded by offering a pair of one-thousand-dollar prizes: one for the first microscope-readable book page shrunk 25,000 times in each direction, and one for the first operating electric motor no larger than a 1/64th-inch cube.

Caltech’s magazine Engineering and Science printed Feynman’s talk, and it was widely reprinted elsewhere. (Popular Science Monthly retitled it “How to Build an Automobile Smaller than This Dot.”) Twenty years later there was a name for the field Feynman had been trying to invent: nanotechnology. Nanotechnologists, partly inspired and partly crackpot, made tiny silicon gears with carefully etched teeth and displayed them proudly in their microscopes; or imagined tiny self-replicating robot doctors that would swim through one’s arteries. They thought of Feynman as their spiritual father, although he himself never returned to the subject. In the crude mechanical sense, tiny machines seemed a feature of a future just as distant as in 1959. The mechanical laws of physics meant that friction, viscosity, and electrical forces did not scale down as neatly as Feynman’s imagined billion tiny factories. Wheels, gears, and levers tended to glue themselves together. Tiny machines had come into being, storing and manipulating information even more efficiently than he had predicted. But they were electronic, not mechanical, using quantum mechanics, not fighting it. Not until 1985 did Feynman have to pay the thousand dollars for tiny writing: a Stanford University graduate student, Thomas H. Newman, spent a month shrinking the first page of A Tale of Two Cities onto silicon by almost exactly the technique Feynman had outlined.

The tiny motor did not take so long. Feynman had underestimated existing technology. A local engineer, William McLellan, read the Engineering and Science article in February. By June, when he had not heard any more, he decided he had better make the motor himself. It took two months of working in his spare time, using a watchmaker’s lathe and a microdrill press, drilling invisible holes and wrapping 1/2000th-inch copper wire. Tweezers were too crude. McLellan used a sharpened toothpick. The result was a one-millionth-horsepower motor.

One day in November he visited Feynman, who was working alone in a Caltech laboratory. McLellan brought his equipment in a large wooden box. He saw Feynman’s eyes glaze; too many cranks had turned up, typically bringing toy automobile engines that they could hold in the palm of a hand. But McLellan opened his box and pulled out a microscope.

“Uh-oh,” Feynman said. He had neglected to make any arrangements for funding the prize. He sent McLellan a personal check.

All His Knowledge

He could not let go of the simple questions. He had spent much of a lifetime assembling a picture of how the world worked, how atoms and forces conjoined to create ice crystals and rainbows. In conjuring a world of miniature machines, he continued to work out possibilities at the level of long-lived molecules, not ephemeral strange particles. He had made himself a member of the community of theoretical physics, and he accepted their goals and their rhetoric: he had told the American Physical Society apologetically that miniaturization was not “fundamental physics (in the sense of, ‘What are the strange particles?’).” Indeed, his community now assigned a kind of intellectual primacy to phenomena that could be observed only in the searing less-than-an-instant of a particle collision. But a part of him still preferred to give fundamental a different definition. “What we are talking about is real and at hand: Nature,” he wrote to a correspondent in India, who had, he thought, spent too much time reading about esoteric phenomena.

Learn by trying to understand simple things in terms of other ideas—always honestly and directly. What keeps the clouds up, why can’t I see stars in the daytime, why do colors appear on oily water, what makes the lines on the surface of water being poured from a pitcher, why does a hanging lamp swing back and forth—and all the innumerable little things you see all around you. Then when you have learned what an explanation really is, you can then go on to more subtle questions.

The first plank in every Caltech undergraduate education was a two-year required course in basic physics. By the 1960s the institute administration recognized a problem. The course had grown stale. Too much ancient pedagogy lingered in it. Bright young freshmen arrived from their high schools around the country, ready to tackle the mysteries of relativity and strange particles, and were plunged into the study of—as Feynman put it—“pith balls and inclined planes.” There was no main lecturer; the course met in sections taught by graduate students. The administration decided in 1961 to revise the course from the bottom up and asked Feynman to take it on for one year. He would have to lecture twice a week.

Caltech was not alone; nor was physics. The pace of change in modern science had accelerated as most college syllabuses had hardened. It was no longer possible, as it had been a generation before, to bring undergraduates up to the live frontier of a field like physics or biology. Yet if quantum mechanics or molecular genetics could not be integrated into undergraduate education, science risked becoming a historical subject. Many first-year physics courses did begin with history: physics in ancient Greece; the pyramids of Egypt and the calendars of Sumeria; medieval physics through nineteenth-century physics. Virtually all began with some form of mechanics. A typical program went:

1. Historical Development of Physical Science

2. Present Status of Physical Science

3. Kinematics: The Study of Motion

4. The Laws of Dynamics

5. Application of the Laws of Motion: Momentum and Energy

6. Elasticity and Simple Harmonic Motion

7. Dynamics of Rigid Bodies

8. Statics of Rigid Bodies

and so on, until in its final weeks the course would reach

26. Atoms and Molecules

in time to touch upon Nuclear Physics and Astrophysics. Caltech was still using a generation-old text by its own luminary, Robert Millikan, that remained soundly mired in the physics of the eighteenth and nineteenth centuries.

Feynman began with atoms, because that was where his own understanding of the world began—not the world of quantum mechanics but the quotidian world of floating clouds and colors shimmering in oily water. Moments after nearly two hundred freshmen entered the hall for his first lecture in the fall of 1961, they heard these words from the grinning physicist striding back and forth upon the stage:

So, what is our over-all picture of the world?

If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis (or the atomic fact, or whatever you wish to call it) that all things are made of atomslittle particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied.

Imagine a drop of water, he said. He took them on a tour inward through the length scales, magnifying the drop until it was forty feet across, then fifteen miles across, then 250 times larger still, until the teeming molecules came into view, each with a pair of hydrogen atoms stuck like round arms upon a larger oxygen atom. He discussed the contrary forces holding the molecules together and forcing them apart. He described heat as atoms in motion … pressure … expansion … steam. He described ice, with its molecules held in a rigid crystalline array. He described the surface of water in air, absorbing oxygen and nitrogen and giving off vapor, and he immediately raised issues of equilibrium and disequilibrium. Instead of Aristotle and Galileo, instead of levers and projectiles, he was building a tangible sense of how atoms create the substances around us and why substances behave as they do. Solution and precipitation, fire and odor—he kept moving, displaying the atomic hypothesis not as a reductive end point but as a road toward complexity.

If water—which is nothing but these little blobs, mile upon mile of the same thing over the earth—can form waves and foam, and make rushing noises and strange patterns as it runs over cement; if all of this, all the life of a stream of water, can be nothing but a pile of atoms, how much more is possible? … Is it possible that the “thing” walking back and forth in front of you, talking to you, is a great glob of these atoms in a very complex arrangement … ? When we say we are a pile of atoms, we do not mean we are merely a pile of atoms, because a pile of atoms which is not repeated from one to the other might well have the possibilities which you see before you in the mirror.

He found that he was working harder than at any time since the atomic bomb project. Teaching was only one of his goals. He realized also that he wished to organize his whole embracing knowledge of physics, to turn it end over end until he could find all the interconnections that were usually, he believed, left as loose ends. He felt as though he were making a map. In fact, for a while he considered actually trying to draw one, a diagram—a “Guide to the Perplexed,” as he put it.

A team of Caltech physics professors and graduate students scrambled to keep up, week after week, designing problem sets and supplementary material, as his guide to the perplexed took shape. They met with him at lunch after each lecture to piece together what Feynman had spun from as little as a single sheet of cryptic notes. Despite the homespun lyricism of his voice, the stress on ideas rather than technique, he was moving quickly, and his fellow physicists had to work to keep up with some of his leaps.

As every physics course recapitulated the subject’s history, so did Feynman’s, but instead of surveying the Sumerians or the Greeks he chose—in his second lecture—to sum up “Physics before 1920.” Less than a half-hour later he was on to a quick tour of quantum physics and then the nuclei and the strange particles according to Gell-Mann and Nishijima. This was what many students wanted to hear. Yet he did not want to leave them with the easy sense that here, at the microlevels, lay the most fundamental laws or the deepest unanswered questions. He described another problem, crossing the artificial boundaries that divide scientific disciplines, “not the problem of finding new fundamental particles, but something left over from a long time ago.”

It is the analysis of circulating or turbulent fluids. If we watch the evolution of a star, there comes a point where we can deduce that it is going to start convection, and thereafter we can no longer deduce what should happen… . We cannot analyze the weather. We do not know the patterns of motions that there should be inside the earth.

No one knew how to derive this chaos from the first principles of atomic forces or fluid flow. Simple fluid problems were for textbooks, he told the freshmen.

What we really cannot do is deal with actual, wet water running through a pipe. That is the central problem which we ought to solve some day.

Feynman designed his lectures as self-contained dramas. He never wanted to end by saying, “Well, the hour is up, we will continue this discussion next time …” He timed his diagrams and equations to fill the sliding two-tier blackboard so definitively that an image of the final chalk tableau seemed to have been in his head from the start. He chose grand themes with tentacles that spread into every corner of science: Conservation of Energy; Time and Distance; Probability … Before a month was out he introduced the deep and timely issue of symmetry in physical laws. His approach to the conservation of energy was revealing. This principle was never far from the consciousness of a working theoretical physicist, yet most textbooks let it arise in passing, toward the end of chapters on mechanical energy or thermodynamics. First they would note that mechanical energy is not conserved, since friction inevitably drains it away. Not until the Einsteinian equivalence of matter and energy does the principle fully come into its own.

Feynman took the conservation of energy as a starting point for discussing conservation laws in general (as a result, his syllabus managed to introduce the conservation of charge, baryons, and leptons weeks before reaching the subject of speed, distance, and acceleration). He put forward an ingenious analogy. Imagine, he said, a child with twenty-eight blocks. At the end of every day, his mother counts them. She discovers a fundamental law, the conservation of blocks: there are always twenty-eight.

One day she sees only twenty-seven, but careful investigation reveals one under the rug. Another day she finds twenty-six—but a window is open, and two are outside. Then she finds twenty-five—but there is a box in the room, and upon weighing the box and weighing individual blocks she surmises that three blocks are inside. The saga continues. Blocks vanish beneath the dirty water of a bathtub, and further calculations are needed to infer the number from the rising water level. “In the gradual increase in the complexity of her world,” Feynman said, “she finds a whole series of terms representing ways of calculating how many blocks are in places where she is not allowed to look.” One difference, he warned: in the case of energy, there are no blocks—just a set of abstract and increasingly intricate formulas which must always, in the end, return the physicist to his starting point.

With the vivid analogies and large themes immediately came computation. In the same one-hour lecture on the conservation of energy, Feynman had his students calculating potential and kinetic energy in a gravitational field. A week later, when he introduced the uncertainty principle of quantum mechanics, he not only conveyed the philosophical drama of this “inherent fuzziness” in the description of nature but also leapt through the calculation of the probability density of an undisturbed hydrogen atom. He still had not reached the basics of speed, distance, and acceleration.

No wonder his colleagues found their nerves jangling as they tried to write problem sets. Before a half-year was gone, he was teaching an uncompromising version of the geometry of relativistic space-time, complete with particle diagrams, geometrical transformations, and four-vector algebra. For college freshmen this was difficult. Along with the mathematics Feynman tried to convey a feeling for how he visualized such problems, placing his “brain” into his diagrams like Alice plunging through the Looking-Glass. He tried to make his students imagine the apparent width and depth of an object:

They depend upon how we look at it; when we move to a new position, our brain immediately recalculates the width and the depth. But our brain does not immediately recalculate coordinates and time when we move at high speed, because we have had no effective experience of going nearly as fast as light to appreciate the fact that time and space are also of the same nature.

The students were sometimes terrified. Yet Feynman also returned to the standard fare of an introductory physics course. When he covered centers of mass and spinning gyroscopes, experienced physicists realized that he was giving the students not just the mathematical methods but also original, physical understanding. Why does a spinning top stand upright on your fingertip and then, as gravity pulls its axis downward, slowly circle about? Even physicists felt they were learning the why for the first time when they heard Feynman explain that the gyroscope began by “falling” an invisibly small distance … (He did not want to leave the students thinking a gyroscope was a miracle: “It is a wonderful thing, but it is not a miracle.”)

No realm of science was out of bounds. After consulting with experts in other fields, he gave two lectures on the physiology of the eye and the physiochemistry of color vision, making a profound connection between psychology and physics. He described the view of time and fields that arose from advanced and retarded potentials, his graduate work with Wheeler. He delivered a special lecture on the principle of least action, beginning with his high-school memories of his teacher Mr. Bader—how does a ball know what path to follow?—and ending with least action in quantum mechanics. He devoted an entire lecture to one of the simplest of mechanical gadgets, the ratchet and pawl, the sawtoothed device that keeps a watch spring from unwinding—but it was a lesson in reversibility and irreversibility, in disorder and entropy. Before he was done he had linked the macroscopic behavior of the ratchet and pawl to the events occurring at the level of its constituent atoms. The history of one ratchet was also the thermodynamic history of the universe, he showed:

The ratchet and pawl works in only one direction because it has some ultimate contact with the rest of the universe… . Because we cool off the earth and get heat from the sun, the ratchets and pawls that we make can turn one way… . It cannot be completely understood until the mystery of the beginnings of the history of the universe are reduced still further from speculation to scientific understanding.

The course was a magisterial achievement: word was spreading through the scientific community even before it ended. But it was not for freshmen. As the months went on, the examination results left Feynman shocked and discouraged. Still, when the year ended, the administration pleaded with him to keep on for a second year, teaching the same students, now sophomores. He did, finally trying to teach a thorough subcourse in quantum mechanics, again reversing the conventional order. Another Caltech physicist, David Goodstein, said long afterward, “I’ve spoken to some of those students in recent times, and in the gentle glow of dim memory, each has told me that having two years of physics from Feynman himself was the experience of a lifetime.” The reality was different:

As the course wore on, attendance by the kids at the lectures started dropping alarmingly, but at the same time, more and more faculty and graduate students started attending, so the room stayed full, and Feynman may never have known he was losing his intended audience.

This was the world according to Feynman. No scientist since Newton had so ambitiously and so unconventionally set down the full measure of his knowledge of the world—his own knowledge and his community’s. With intensive editing by other physicists, chiefly Robert B. Leighton and Matthew Sands, the lectures became the famous “red books”—the three-volume Feynman Lectures on Physics. Colleges and universities worldwide tried to adopt them as textbooks and then, inevitably, gave them up for more manageable and less radical alternatives. Unlike true textbooks, however, Feynman’s volumes continued to sell steadily a generation later.

Adorning each volume was a picture of Feynman in shirtsleeves, gleefully pounding a bongo drum. He came to regret that. “It is odd,” he said after hearing himself introduced yet again as a bongo player, “but on the infrequent occasions when I have been called upon in a formal place to play the bongo drums, the introducer never seems to find it necessary to mention that I also do theoretical physics. I believe that is probably because we respect the arts more than the sciences.” And when yet another request came in for a copy of the photograph—from a Swedish encyclopedia publisher who wished to “give a human approach to a presentation of the difficult matter that theoretical physics represents”—he exploded. “Dear Sir,” he scrawled,

The fact that I beat a drum has nothing to do with the fact that I do theoretical physics. Theoretical physics is a human endeavor, one of the higher developments of human beings—and this perpetual desire to prove that people who do it are human by showing that they do other things that a few other humans do (like playing bongo drums) is insulting to me.

I am human enough to tell you to go to hell.

The Explorers and the Tourists

“When you have learned what an explanation really is,” Feynman had said, “you can then go on to more subtle questions.”

Creeping philosophy. What is an explanation? Science and scientists had commandeered the practice of explanation, but the theory they left mainly to philosophers. The why seemed to fall in their domain. “With this question philosophy began and with this question it will end,” Martin Heidegger had recently said, “provided that it ends in greatness and not in an impotent decline.” Feynman, who believed that the impotent decline was well under way in the academies that supported philosophers, realized that he had had to develop a view of what constituted explanation, what legitimized explanation, and which phenomena did and did not require explanation.

His understanding of explanation did not depart far from the modern philosophical mainstream, though its jargon of explanans and explanandum was an alien language to him. Like most philosophers, he found explanations most satisfactory when they called upon a generalizing, underlying “law.” A thing is the way it is because other things of its kind are all that way. Why does Mars travel around the sun in an ellipse? Feynman explained—and ventured deep into philosophical territory—in an invited lecture series at Cornell University in 1964. He began by speaking, nominally, about the law of gravitation. In reality his subject was explanation itself.

All satellites travel in elliptical orbits. Why? Because objects tend to travel in a straight line when left alone (the law of inertia) and the combination of that unchanging motion and a force exerted toward a center of gravity—by the law of gravitation—creates an ellipse. What validates the law of gravitation? Feynman expressed the scientist’s modern view, a blend of the pragmatic and the aesthetic. He cautioned that even so beautiful a law was provisional: Newton’s law of gravitation gave way to Einstein’s, and a necessary quantum modification eluded physicists even now.

That is the same with all our other laws—they are not exact. There is always an edge of mystery, always a place where we have some fiddling around to do yet. This may or may not be a property of Nature, but it certainly is common to all the laws as we know them today.

Yet in its unfinished form the law of gravitation explained so much. To a practicing scientist, that validated it. The same small parcel of mathematics explained Tycho Brahe’s nightly observations of the planets in the sixteenth century and Galileo’s measurements of balls rolling down inclined planes, timed against the beat of his own pulse. The planets are falling, Newton reasoned; the moon feels the same force as an earthly projectile, the force weakening with the square of the distance. A law is not a cause—philosophers still wrestled with this distinction—yet it is more than merely a description. It precedes the thing explained, not in time but in generality or in profundity. The same law explained the earth’s symmetrically bulging tides, rising both toward and away from the moon, and the newly measured orbits of the moons of Jupiter. It made new predictions that scientists could confirm or disprove with experiments on balls hanging delicately in a laboratory or observations of majestically rotating galaxies a hundred million million times larger. “Exactly the same law,” Feynman said, and added—having struggled to find the right wording—

Nature uses only the longest threads to weave her pattern, so each small piece of the fabric reveals the organization of the entire tapestry.

Meanwhile, why does an object in motion tend to travel forever in a straight line? That, Feynman said, nobody knows. At some deep stage, the explanations must end.

“Science repudiates philosophy,” Alfred North Whitehead had said. “In other words, it has never cared to justify its truth or explain its meaning.” Feynman’s colleagues liked to think of their gruffly plain-spoken pragmatist hero as the perfect antiphilosopher, doing rather than justifying. His own rhetoric encouraged them. He lacked patience for the now-popular What is reality? brand of speculation arising from quantum-mechanical paradoxes. Yet he could not repudiate philosophy; he had to find ways to justify the truth that he and his colleagues sought. The modern physics had banished any possibility of discovering a system of laws unambiguously tying effects to causes; or a system of laws deduced and conjoined with perfect logical consistency; or a system of laws rooted in the objects that people can see and feel. For philosophers, these had all been marks of a sound explanatory law. Now, however, a particle might or might not decay, an electron might or might not pass through a slit in a screen. A minimum principle like the principle of least action might be derived from laws of forces and motion, or those laws might depend on the principle: who could say with logical certainty? And the basic stuff of science had grown inexorably more abstract. As the physicist David Park put it: “None of the entities that appear in fundamental physical theory today are accessible to the senses. Even more … there are phenomena that apparently are not in any way amenable to explanation in terms of things, even invisible things, that move in the space and time defined by the laboratory.” With all these traditional virtues removed—or worse, partly removed while still partly necessary—it fell to science to build a new understanding of the nature of explanation. Or so Feynman argued: the philosophers themselves, he said, were always a tempo behind, like tourists moving in after the explorers have left.

Scientists had their own forms of blindness. It was often said in the quantum-mechanical era—Feynman had said it himself—that the only true test of a theory was its ability to produce good numbers, numbers agreeing with experiment. The American pragmatism of the early twentieth century had brought forth views like Slater’s at MIT: “Questions about a theory which do not affect its ability to predict experimental results correctly seem to me quibbles about words.” Yet Feynman now felt a hollowness in the purely operational view of what a theory means to a scientist. He recognized that theories came laden with mental baggage, with what he called a philosophy, in fact. He had trouble defining this: “an understanding of the law”; “a way that a person holds the laws in his mind …” The philosophy could not be discarded as readily as a pragmatic scientist might suggest.

Consider a Mayan astronomer, he suggested. (In Mexico he had grown interested in the deciphering of the great ancient codices, hieroglyphic manuscripts that employed long tables of bars and dots to set down an intricate knowledge of the movements of sun, moon, and planets. Codes, mathematics, and astronomy—eventually he delivered a lecture at Caltech on deciphering Mayan hieroglyphics. Afterward, Murray Gell-Mann “countered,” Feynman said, with a series of six lectures on the languages of the world.) The Maya had a theory of astronomy that enabled them to explain their observations and to make predictions long into the future. It was a theory in the utilitarian modern spirit: a set of rules, quite mechanical, which when followed produced accurate results. Yet it seemed to lack a kind of understanding. “They counted a certain number and subtracted some numbers, and so on,” he said. “There was no discussion of what the moon was. There was no discussion even of the idea that it went around.”

Now a “young man” approaches the astronomer with a new idea. What if there are balls of rock out there, far away, moving under the influence of forces just like the forces that pull rocks to the ground? Perhaps it would make possible a different way of calculating the motions of the heavenly bodies. (Feynman certainly had memories of a young man confronting his elders with new, half-formed physical intuitions.)

“Yes,” says the astronomer, “and how accurately can you predict eclipses?” He says, “I haven’t developed the thing very far yet.” Then says the astronomer, “Well, we can calculate eclipses more accurately than you can with your model, so you must not pay any attention to your idea because obviously the mathematical scheme is better.”

The notion that alternative theories could account plausibly for the same observations had slipped into a central position in the working philosophy of scientists. Philosophers called it empirical equivalence, when they began to catch up. The recent history of quantum mechanics had pivoted on the empirical equivalence of Heisenberg’s and Schrödinger’s versions. The empirical equivalence of very different-seeming theories could be demonstrated mathematically, as Dyson had shown for Feynman’s and Schwinger’s quantum electrodynamics. Scientists knew, usually without thinking about it, that empirically equivalent theories could have different consequences, mathematics and logic notwithstanding.

For Feynman, especially, the tension between alternative theories served as a creative force, an engine for generating new knowledge. Perhaps more than any living physicist, he had made a specialty of learning what models could be derived from which principles, and what models from each other. To Dyson’s astonishment, he had stood at a blackboard one day in 1948 and interrupted their heady discussions of quantum electrodynamics to show him something different. Sketching quickly, he derived the nineteenth-century Maxwell field equations—the classical understanding of electricity and magnetism—backward from the new quantum mechanics. Einstein had started with the Maxwell equations and then shifted the perspective of the observer to arrive at his theory of relativity; Feynman went the other way in a fit of ahistorical perversity. He began with a void, no fields or waves, no concept of relativity, not even a notion of light itself, just a single particle obeying quantum mechanics’ odd rules. Before Dyson’s eyes he traveled back mathematically from the new physics, with its riddles of uncertainty and immeasurability, to the comforting exactitude of the previous century. He showed that Maxwell’s field equations were not a foundation but a consequence of the new quantum mechanics. Startled and impressed, Dyson urged him to publish. Feynman just laughed and said, “Oh, no, it’s not serious.” As Dyson understood it later, Feynman had been trying to create a new theory “outside the framework of conventional physics.”

His motivation was to discover a new theory, not to reinvent the old one… . His purpose was to explore as widely as possible the universe of particle dynamics. He wanted to make as few assumptions as he could.

A theorist who can juggle different theories in his mind has a creative advantage, Feynman argued, when it comes time to change the theories. The path-integral formulation of quantum mechanics might be empirically equivalent to other formulations and yet—given less-than-omniscient human physicists—find more natural-seeming application to realms of science not yet explored. Different theories tended to give a physicist “different ideas for guessing,” Feynman said. And the century’s history had shown that when even so elegant and pure a theory as Newton’s had to be replaced, slight modifications could not suffice.

To get something that would produce a slightly different result it had to be completely different. In stating a new law you cannot make imperfections on a perfect thing; you have to have another perfect thing.

He understood explanations as a surgeon understands knives. He had a set of practical tests, heuristics, that he applied when reaching a judgment about a new idea in physics: for example, did it explain something unrelated to the original problem. He would challenge a young theorist: What can you explain that you didn’t set out to explain? He knew that why? is a question without an end and that our knowledge of things is inextricable from the language we use. The words and analogies from which we build our explanations are culpably linked with the things explained. Explanans and explanandum are inextricable after all. An interviewer for the British Broadcasting Corporation, Christopher Sykes, once asked him to explain magnets: “If you get hold of two magnets and you push them you can feel this pushing between them… . Now what is it, the feeling between those two magnets?”

“What do you mean, what’s the feeling?” Feynman growled. His hair, swept back in dramatic gray waves, had receded high atop his head, leaving a statue’s high brow above a pair of heavy eyebrows that curled more impishly than ever. His pale blue shirt was open at the collar. A pen and eyeglass case rested in his front pocket, as always. Off camera, a defensive note entered the interviewer’s voice.

“Well, there’s something there, isn’t there? The sensation is that there’s something there when you push these two magnets together.”

“Listen to my question,” Feynman said. “What is the meaning when you say there’s a feeling? Of course you feel it. Now what is it you want to know?”

“What I want to know is what’s going on between these two bits of metal.”

“The magnets repel each other.”

“But what does that mean? Or why are they doing that? Or how are they doing that?” Feynman shifted in his easy chair, and the interviewer added, “I must say I think that’s a perfectly reasonable question to ask.”

“Of course it’s a reasonable—it’s an excellent question, okay?” Reluctantly, Feynman now stepped into metaphysics. Particle theorists were toying with a “bootstrap” model, in which no particle lies at a deepest level, but all are interdependent composites. The name bootstrap paid homage to the paradoxical circularity of having to build each fundamental particle from all the others. Feynman, as he now made clear, believed in a kind of bootstrap model of explanation itself.

You see, when you ask why something happens, how does a person answer why something happens?

For example, Aunt Minnie is in the hospital. Why? Because she went out on the ice and slipped and broke her hip. That satisfies people. But it wouldn’t satisfy someone who came from another planet and knew nothing about things… . When you explain a why, you have to be in some framework that you’ve allowed something to be true. Otherwise you’re perpetually asking why… . You go deeper and deeper in various directions.

Why did she slip on the ice? Well, ice is slippery. Everybody knows that—no problem. But you ask why is ice slippery… . And then you’re involved with something, because there aren’t many things as slippery as ice… . A solid that’s so slippery?

Because it is in the case of ice that when you stand on it, they say, momentarily the pressure melts the ice a little bit so that you’ve got an instantaneous water surface on which you’re slipping. Why on ice and not on other things? Because water expands when it freezes. So the pressure tries to undo the expansion and melts it… .

I’m not answering your question, but I’m telling you how difficult a why question is. You have to know what it is that you’re permitted to understand … and what it is you’re not.

You’ll notice in this example that the more I ask why, it gets interesting after a while. That’s my idea, that the deeper a thing is, the more interesting… .

Now when you ask why two magnets repel, there are many different levels. It depends whether you’re a student of physics or an ordinary person who doesn’t know anything.

If you don’t know anything at all, about all I can say is that there’s a magnetic force that makes them repel. And that you’re feeling that force. Well, you say that’s very strange because I don’t feel a force like that in other circumstances… . You’re not at all disturbed by the fact that when you put your hand on the chair it pushes you back. But we found out by looking at it that that’s the same force… . It turns out that the magnetic and electric force with which I wish to explain these things is the deeper thing that we would start with to explain many other things… .

If I said that magnets attract as if they were connected with rubber bands, I would be cheating you, because they’re not connected with rubber bands… . If you were curious enough you’d ask me why rubber bands tend to pull back together again, and I would end up explaining that in terms of electrical forces—which are the very things I was using the rubber bands to explain, so I have cheated very badly, you see.

So I am not going to be able to give you an answer to why magnets attract. Except to tell you that they do … I really can’t do a good job—any job—of explaining the electromagnetic force in terms of something you’re more familiar with, because I don’t understand it in terms of anything else that you’re more familiar with.

He sat back and grinned.

To the professionals Feynman’s musings were not philosophy but a charmingly naive folk wisdom. He was both after and ahead of his time. Academic epistemology was still wrestling with unknowability. What choice did they have, in light of scientific relativity and uncertainty, the abandonment of strict causality and the pervasiveness of ever-qualified probabilities? No more certainties, no more absolutes. The Harvard philosopher W. V. Quine mused, “I think that for scientific or philosophical purposes the best we can do is give up the notion of knowledge as a bad job… .” Not knowing had its ironies as well as its pleasures. For philosophers this was “the post-scholastic era,” as a later physicist, John Ziman, put it, “when it seemed essential to (dis)prove the peculiar (un)reality of scientific knowledge (theories/facts/data/hypotheses) by analysing (deconstructing) the arguments on which it was (supposedly) based.” Scientists themselves, in the knowledge business, had no use for this mode of discourse. Judged by results, their understanding of nature seemed richer and more efficacious than ever, the quantum paradoxes notwithstanding. They had rescued knowledge from uncertainty after all. “The scientist has a lot of experience with ignorance and doubt and uncertainty,” Feynman said. “… we take it for granted that it is perfectly consistent to be unsure—that it is possible to live and not know. But I don’t know whether everyone realizes that this is true.”

Feynman’s gift to his coworkers was a credo, accreted over time and disbursed both formally and informally, in lectures and books like the 1965 Character of Physical Law and in a stance, an attitude, that seemed too natural to constitute a philosophy.

He believed in the primacy of doubt, not as a blemish upon our ability to know but as the essence of knowing. The alternative to uncertainty is authority, against which science had fought for centuries. “Great value of a satisfactory philosophy of ignorance,” he jotted on a sheet of notepaper one day. “… teach how doubt is not to be feared but welcomed.”

He believed that science and religion are natural adversaries. Einstein said, “Science without religion is lame; religion without science is blind.” Feynman found this style of accommodation to be intolerable. He repudiated the conventional God: “the kind of a personal God, characteristic of Western religions, to whom you pray and who has something to do with creating the universe and guiding you in morals.” Some theologians had retreated from the conception of God as a kind of superperson—Father and King—willful, white-haired, and male. Any God who might take an interest in human affairs was too anthropomorphic for Feynman—implausible in the less and less human-centered universe discovered by science. Many scientists agreed, but his views were so rarely expressed that in 1959 a local television station, KNXT, felt obliged to suppress an interview in which he declared:

It doesn’t seem to me that this fantastically marvelous universe, this tremendous range of time and space and different kinds of animals, and all the different planets, and all these atoms with all their motions, and so on, all this complicated thing can merely be a stage so that God can watch human beings struggle for good and evil—which is the view that religion has. The stage is too big for the drama.

Religion meant superstition: reincarnation, miracles, virgin birth. It replaced ignorance and doubt with certainty and faith; Feynman was happy to embrace ignorance and doubt.

No scientist liked the God of Sunday school stories or the “God of the gaps”—the last-resort explanation for the unexplainable, called on through the ages to fill holes in current knowledge. Those who did turn to faith as a supplement to science preferred grander and less literal gods: “the ground of all that is,” as John Polkinghorne, a high-energy physicist turned Anglican priest, said: “Those who are seeking understanding through and through—a natural instinct for the scientist—are seeking God, whether they name him or not.” Their God did not fill gaps in the sense of particular lacunae for evolutionary theory or astrophysics—how did the universe begin?—but hovered over whole domains of knowledge: ethics, aesthetics, metaphysics. Feynman conceded the existence of genuine knowledge outside the range of science. He admitted that there were questions science could not answer, but grudgingly: he saw a danger in tying moral guidance to unpalatable myths, as religion did, and he resented the common view that science, with its merciless unraveling and explaining, was an enemy of the emotional appreciation of beauty. “Poets say science takes away from the beauty of the stars—mere globs of gas atoms,” he wrote in a famous footnote.

I too can see the stars on a desert night, and feel them. But do I see less or more? The vastness of the heavens stretches my imagination—stuck on this carousel my little eye can catch one-million-year-old light. A vast pattern—of which I am a part… . What is the pattern, or the meaning, or the why? It does not do harm to the mystery to know a little about it. For far more marvelous is the truth than any artists of the past imagined it. Why do the poets of the present not speak of it? What men are poets who can speak of Jupiter if he were a man, but if he is an immense spinning sphere of methane and ammonia must be silent?

He believed, too, in an independence of moral belief from any particular theory of the machinery of the universe. An ethical system that depended on faith in a watchful or vengeful God was unnecessarily fragile, prone to collapse when doubt began to undermine faith.

He believed that it was not certainty but freedom from certainty that empowered people to make judgments about right and wrong: knowing that they could never be more than provisionally right, but able to act nonetheless. Only by understanding uncertainty could people learn how to evaluate the many kinds of false knowledge that bombard them: claims of mind reading and spoon bending, belief in flying saucers bearing alien visitors. Science can never disprove such claims, any more than it can disprove God. It can only devise experiments and explore alternative explanations until it gains a commonsense sureness. “I have argued flying saucers with lots of people,” Feynman once said. “I was interested in this: they keep arguing that it is possible. And that’s true. It is possible. They do not appreciate that the problem is not to demonstrate whether it’s possible or not but whether it’s going on or not.”

How could one evaluate miracle cures or astrological forecasts or telekinetic victories at the roulette wheel? By subjecting them to the scientific method. Look for people who recovered from leukemia withouthaving prayed. Place sheets of glass between the psychic and the roulette table. “If it’s not a miracle,” he said, “the scientific method will destroy it.” It was essential to understand coincidence and probability. It was noteworthy that flying-saucer lore involved a considerably greater variety of saucer than of creature: “orange balls of light, blue spheres which bounce on the floor, gray fogs which disappear, gossamer-like streams which evaporate into the air, thin, round flat things out of which objects come with funny shapes that are something like a human being.” It was fantastically improbable, he noted, that alien visitors should come in near-human form and just at the moment in history when people discovered the possibility of space travel.

He subjected other forms of science and near-science to the same scrutiny: tests by psychologists, statistical sampling of public opinion. He had developed pointed ways of illustrating the slippage that occurred when experimenters allowed themselves to be less than rigorously skeptical or failed to appreciate the power of coincidence. He described a common experience: an experimenter notices a peculiar result after many trials—rats in a maze, for example, turn alternately right, left, right, and left. The experimenter calculates the odds against something so extraordinary and decides it cannot have been an accident. Feynman would say: “I had the most remarkable experience… . While coming in here I saw license plate ANZ 912. Calculate for me, please, the odds that of all the license plates …” And he would tell a story from his days in the fraternity at MIT, with a surprise ending.

I was upstairs typewriting a theme on something about philosophy. And I was completely engrossed, not thinking of anything but the theme, when all of a sudden in a most mysterious fashion there swept through my mind the idea: my grandmother has died. Now of course I exaggerate slightly, as you should in all such stories. I just sort of half got the idea for a minute… . Immediately after that the telephone rang downstairs. I remember this distinctly for the reason you will now hear… . It was for somebody else. My grandmother was perfectly healthy and there’s nothing to it. Now what we have to do is to accumulate a large number of these to fight the few cases when it could happen.

Feynman, who had once astonished the Princeton admissions committee with his low scores in every subject but physics and mathematics, did believe in the primacy of science among all the spheres of knowledge. He would not concede that poetry or painting or religion could reach a different kind of truth. The very idea of different, equally valid versions of truth struck him as a modern form of cant, another misunderstanding of uncertainty.

That any particular knowledge—quantum mechanics, for example—must be provisional and imperfect does not mean that competing theories cannot be judged better or worse. He was not what philosophers called a realist—by one definition, someone who, in asserting the existence of, say, electrons, adds “a desk-thumping, foot-stamping shout of ‘Really!’” Real though electrons seemed, Feynman and some other physicists recognized that they are part of a never-perfect, always-changing scaffolding. Do electrons really travel backward in time? Are those nanosecond resonances really particles? Do particles really spin? Do they really have strangeness and charm? Many scientists believed in a straightforward reality. Others, including Feynman, felt that in the late twentieth century it was not necessary or possible to answer a final yes. It was preferable to hold one’s models delicately in the mind, weighing alternative viewpoints and letting assumptions slide here and there. But to physicists the scaffolding was not all. It did imply a truth within, toward which humans might perpetually strive, however imperfectly. Feynman did not believe, as many philosophers did, that the now-famous “conceptual revolutions” or “paradigm shifts” to which science seemed so prone—Einstein’s relativity replacing Newton’s dynamics—amounted to the replacing of one socially bound fashion by another, like hemlines rising and falling year to year. Like most members of his community, he could not abide in his business what one philosopher, Arthur Fine, called “the great lesson of twentieth-century analytic and continental philosophy, namely, that there are no general methodological or philosophical resources for deciding such things.” Scientists do have methods. Their theories are provisional but not arbitrary, not mere social constructions. By means of the peculiar stratagem of refusing to acknowledge that any truth may be as valid as any other, they succeed in preventing any truth from becoming as valid as any other. Their approach to knowledge differs from all others—religion, art, literary criticism—in that the goal is never a potpourri of equally attractive realities. Their goal, though it always recedes before them however they approach it, is consensus.

The Swedish Prize

When Einstein won the 1921 Nobel Prize, it did not create a stir. Although Einstein could command front-page coverage in the New York Times merely by delivering a public lecture, the detail of the prize impressed the editors only to the extent of a one-sentence notice inside the newspaper, lumping him with the next year’s winner, a more obscure professor whose name they misspelled:

The Nobel Committee has awarded the physics prize for 1921 to Professor Dr. Albert Einstein of Germany, identified with the theory of relativity, and that for 1922 to Professor Neils Bohr, Copenhagen.

Gradually the awards gained in stature. Longevity contributed: there were other prizes, but the foresighted Alfred Nobel, inventor of dynamite, had established his early. The particular contributions of scientists grew more difficult to describe to a lay public, and the awarding of such a distinguished international honor provided a useful benchmark. A physicist’s obituary in the late twentieth century would almost have to begin with the phrase “won the Nobel Prize for …” or the phrase “worked on the atomic bomb,” or both. The prize committee arrived at its judgments with care: it made errors, sometimes serious ones, but it generally reflected a conservative consensus of leading scientists in many countries. Scientists began to covet the prize with an intensity that they suppressed as well as they could. Their interest could be felt nonetheless in the ways scientists did and did not discuss the prize. Any potential prizewinner exhibited an extreme reluctance to mention its name. The distinguished group of those who had almost won revealed a forlorn tendency to rehearse for the rest of their lives the slight contingencies that had stood between them and the prize—the indecision that made them delay a paper for a crucial few months, or the timidity that kept them from joining a team embarked on an all-too-promising experiment. Even winners showed how much they cared through small mannerisms, such as the euphemism winkingly employed by Gell-Mann, among others: “the Swedish prize.” The winners formed an elite group—but elite was too weak a word. A sociologist assessing the prize’s stature found herself having to multiply superlatives: “As the ne plus ultra of honors in science, the Nobel Prize elevates its recipients not merely to the scientific elite but to the uppermost rank of the scientific ultra-elite, the thin layer of those at the top of the stratification hierarchy of elites who exhibit especially great influence, authority, or power and who generally have the highest prestige within what is a prestigious collectivity to begin with.” Physicists always knew who among their colleagues had won and who had not.

Few scientists after Einstein, if any, remained larger than the prize—capable of adding as much to its stature as it added to theirs. In 1965 several active physicists at least seemed to be sure future winners, as much because of their dominance in the community as because of their particular accomplishments. Feynman, Schwinger, Gell-Mann, and Bethe were chief among them. The Nobel committee traditionally found it easier to identify worthy candidates than to pinpoint their most worthy particular achievements. Most notoriously, Einstein had won specifically for his work on the photoelectric effect, not for relativity. When Bethe finally did win, in 1967, the prize singled out his parsing of the thermonuclear reactions in stars—important work, but an arbitrary choice from an unusually broad and influential career spanning decades. Feynman could plausibly have won for his liquid-helium work, had that been his only achievement. Each fall, as the announcement neared, Feynman had been alive to the possibility. He and Gell-Mann might have won for their theory of weak interactions, yet Gell-Mann had already moved on to a more sweeping model of high-energy particle physics. The committee found it easier to reward particular experiments or discoveries, and experimenters tended to win their prizes far more promptly than theorists. Broad theoretical conceptions like relativity were the most difficult of all. Even so, it was odd that the Nobel committee had not yet recognized the theoretical watershed reached almost twenty years before with quantum electrodynamics and renormalization. The experimenters Willis Lamb and Polykarp Kusch had long since been recognized, in 1955, for their contributions to quantum electrodynamics.

No more than three people may share a Nobel Prize. That rule may have added to the complications in the case of quantum electrodynamics. Feynman and Schwinger were two. Tomonaga had matched or anticipated the essence of Schwinger’s theory, even if his version had not been quite as panoramic. Dyson was a problem. His contribution had been the most mathematical, and the Nobel Prize abhorred mathematics. Some physicists felt vehemently that Dyson had done no more than analyze and publicize work created by others. Dyson, having settled at the Institute for Advanced Study, drifted away from the theoretical physics community. He had no taste for the involutions of particle physics. He indulged his lifelong passion for space travel by participating in various visionary projects. He grew fascinated with the global politics of nuclear weapons and with the origin of life. The Nobel recommendations of influential American physicists—his old antagonist Oppenheimer among them—may have omitted Dyson, although to a knowledgeable minority it seemed that no one, during the tumultuous birth of modern quantum electrodynamics, had understood the problem more broadly or influenced the community more deeply.

Thus, when the Western Union “telefax” arrived at 9 A.M. on October 21, 1965, it named Feynman, Schwinger, and Tomonaga for their “fundamental work in quantum electrodynamics with deep ploughing consequences for the physics of elementary particles.” By then Feynman had been awake for more than five hours. The first call had come at 4 A.M. from a correspondent of the American Broadcasting Corporation shortly after the announcement in Stockholm. He rolled over and told Gweneth. At first she thought he was joking. The telephone kept ringing until finally they left it off the hook. They could not get back to sleep. Feynman knew his life would not be the same. Photographers from the Associated Press and the local newspaper were at his house before sunrise. He posed outdoors in the dark with Carl, his sleepy three-year-old, and gamely held a telephone receiver to his ear as the flashbulbs popped.

Since the press now had to give an account of quantum electrodynamics for the first time, Feynman rapidly learned to field a sequence of variations on what seemed to him a single question: “Will you please tell us what you won the prize for—but don’t tell us! Because we’ll not understand it.” The actual questions were impossible to answer: “What applications does this paper have in the computer industry?” “I’m going to ask you also to comment on the statement that your work was to convert experimental data on strange particles into hard mathematical fact.” And then the one question he could answer: “What time did you hear about the award?” In a private moment a reporter for Time made a suggestion he loved: that he simply say, “Listen, buddy, if I could tell you in a minute what I did, it wouldn’t be worth the Nobel Prize.” He realized that he could work up a stock phrase about the interaction of matter and radiation but felt it would be a fraud. He did make a serious remark—and repeated it all day—that reflected his inner feeling about renormalization. The problem had been to eliminate infinities in calculations, he said, and “We have designed a method for sweeping them under the rug.”

Julian Schwinger called, and they shared a happy moment. Schwinger, still at Harvard, was pursuing an ever more solitary road in his theoretical physics but, unlike Feynman, had brought forth a long and distinguished string of graduate students working on the frontier problems of high-energy physics. A decade earlier, when Feynman won the Einstein Award, he wrote his mother: “I thought you would be happy that I beat Schwinger out at last, but it turns out he got the thing 3 yrs ago. Of course, he only got ½ a medal, so I guess you’ll be happy. You always compare me with Schwinger.” Now their rivalry was over, if not forgotten. Feynman called Tomonaga in Japan and then reported to a student journalist a capsule caricature of the Nobel Prize-day telephone conversation:

[FEYNMAN:] Congratulations.

[TOMONAGA:] Same to you.

How does it feel to be a Nobel Prize winner?

I guess you know.

Can you explain to me in layman’s terms exactly what it was you did to win the prize?

I am very sleepy.

By afternoon students had raised across the dome of Throop Hall an enormous cloth banner reading, “Win big, RF.”

Hundreds of letters and telegrams came in over the next weeks. He heard from childhood friends who had not seen him in almost forty years. There were cables from shipboard and muffled telephone calls from Mexico. He told reporters that he planned to spend his third of the $55,000 prize money to pay his taxes on his other income (actually he used it to buy a beach house in Mexico). He felt himself under stress. He had always felt that honors were suspect. He liked to ridicule pomp and talk about his father, the uniform salesman who taught him to see past the uniforms. Now he would be traveling to Sweden to appear before the king. The mere thought of buying a tuxedo made him nervous. He did not want to bow before a foreign potentate. For several weeks he grew obsessed with an odd fantasy that one was forbidden to turn one’s back on the king and therefore had to back up a flight of steps after receiving the award. He practiced jumping backward up steps, both feet at once, because he decided that he would invent a method that no one had used before. He planned to examine the actual steps in advance and rehearse. One friend sent him a rear-view mirror from an automobile as a joke; Feynman took it as evidence that other people knew about this rule. When Sweden’s ambassador paid him a courtesy call, Feynman took the opportunity to confess his worry. The ambassador assured him that he could face any direction he chose; no one climbed stairs backward.

In the event, he put on white tie and tails, slicked his hair down, and grinned as he accepted the award from a bespectacled King Gustav VI Adolf. The prizewinners sped through a week of banquets, dances, formal toasts, and impromptu speeches in Sweden’s ornate and palatial civic buildings. They traveled from Stockholm to Uppsala and back, partied with students in a beer cellar, and made conversation with ambassadors and princesses. They collected their medals, certificates, and bank checks. They delivered their Nobel Prize lectures. Feynman realized that he had never read anyone’s Nobel lecture. Scientists’, especially, seemed automatically obscure. Friends told him about William Faulkner’s famous speech in 1950 (“I believe that man will not merely endure: he will prevail”); he did not think he could produce anything so grand, but he wanted to say something memorable, and he did not want to give the précis of quantum electrodynamics that might also be coming from his fellow winners.

He believed that historians, journalists, and scientists themselves all participated in a tradition of writing about science that obscured the working reality, the sense of science as a process rather than a body of formal results. Real science was confusion and doubt, ambition and desire, a march through fog. With hindsight, the polished histories tended to impose a post facto logic on the sequence of reasoning and discovery. The appearance of an idea in the scientific literature and the actual communication of the same idea through the community could be sharply different, Feynman knew. He decided to give a personal, anecdotal, and—he claimed—unpolished version of his route to the space-time view of quantum electrodynamics. “We have a habit in writing articles published in scientific journals to make the work as finished as possible,” he began, “to cover up all the tracks, to not worry about the blind alleys or to describe how you had the wrong idea first.”

He described the historic difficulty of infinities in the self-interaction of the electron. He confessed his secret desire as a graduate student to eliminate the field altogether—to produce a theory of direct action between charges. He recounted his collaboration with Wheeler: “as I was stupid, so was Professor Wheeler that much more clever.” He tried to give his listeners a feeling for what had seemed a new philosophical stance—the willingness of a physicist in the post-Einstein era to accept paradoxes without stopping to say, “Oh, no, how could that be?”—and offered his memory of the way his physical viewpoint had evolved. He repeated his view of renormalization: “I think that the renormalization theory is simply a way to sweep the difficulties of the divergences of electrodynamics under the rug. I am, of course, not sure of that.”

He pointed out a remarkable irony of the story. So many of the ideas he nursed on his way to his Nobel Prize-winning work had themselves proved faulty: his first notion that a charge should not act on itself; the whole Wheeler-Feynman half-advanced, half-retarded electrodynamics. Even his path integrals and his view of electrons moving backward in time were only aids to guessing, not essential parts of the theory, he said.

The method used here, of reasoning in physical terms, therefore, appears to be extremely inefficient. On looking back over the work, 1 can only feel a kind of regret for the enormous amount of physical reasoning and mathematical re-expression… .

But he also believed that the inefficiency, the guessing of equations, the juggling of alternative physical viewpoints were, even now, the key to discovering new laws. He concluded with advice to students:

The chance is high that the truth lies in the fashionable direction. But, on the off-chance that it: is in another direction—a direction obvious from an unfashionable view of field theory—who will find it? Only someone who has sacrificed himself by teaching himself quantum electrodynamics from a peculiar and unfashionable point of view; one that he may have to invent for himself.

He left Stockholm for Geneva, where he repeated the talk before a jubilant, reverent audience at Europe’s great new accelerator center, CERN, the European Center for Nuclear Research. He said, standing before them in his new dress suit, that the new laureates had been talking about whether they would ever be able to return to normal. Jacques Monod, who shared the prize for medicine, had declared it was a biological fact that an organism is changed by experience. “I discovered a great difficulty,” Feynman said, grinning malevolently. “I always took off my coat in giving a lecture, and I just don’t feel like taking it off.” As he continued, “I’ve changed! I’ve changed!” the audience erupted in laughter and catcalls. He took off the coat.

Once more, he said he would speak as an old man to the young scientists and urge them to break away from the pack. At CERN, as at all the laboratories of high-energy physics, the pack was growing rapidly. Every experiment required enormous teams. Author lists for articles in the Physical Review were beginning to take up a comically large portion of the page.

“It will not do you any harm whatever to think in an original fashion,” Feynman said. He offered a probabilistic argument.

The odds that your theory will be in fact right, and that the general thing that everybody’s working on will be wrong, is low. But the odds that you, Little Boy Schmidt, will be the guy who figures a thing out, is not smaller… . It’s very important that we do not all follow the same fashion. Because although it is ninety percent sure that the answer lies over there, where Gell-Mann is working, what happens if it doesn’t?

“If you give more money to theoretical physics,” he added, “it doesn’t do any good if it just increases the number of guys following the comet head. So it’s necessary to increase the amount of variety … and the only way to do it is to implore you few guys to take a risk with your lives that you will never be heard of again, and go off in the wild blue yonder and see if you can figure it out.”

Most scientists knew the not-so-amusing metalaw that the receipt of the Nobel Prize marks the end of one’s productive career. For many recipients, of course, the end came long before. For others the fame and distinction tend to accelerate the waning of a scientist’s ability to give his creative work the time-intensive, fanatical concentration it often requires. Some prizewinners fight back. Francis Crick designed a blunt form letter:

Dr. Crick thanks you for your letter but regrets that he is unable to accept your kind invitation to:

send an autograph

help you in your project

provide a photograph

read your manuscript

cure your disease

deliver a lecture

be interviewed

attend a conference

talk on the radio

act as chairman

appear on TV

become an editor

speak after dinner

write a book

give a testimonial

accept an honorary degree

Requests in most of these categories now filled Feynman’s mail (except that his correspondents tended more toward hear my theory of the universe than cure my disease). Mature scientists did become laboratory heads, department chairmen, foundation officials, institute directors. Victor Weisskopf, one of those whom the prize had just barely eluded, was now director of CERN, and he thought Feynman, too, would be driven willy-nilly into administration. He goaded Feynman into accepting a wager, signed before witnesses: “Mr. FEYNMAN will pay the sum of TEN DOLLARS to Mr. WEISSKOPF if at any time during the next TEN YEARS (i.e. before the THIRTY FIRST DAY of DECEMBER of the YEAR ONE THOUSAND NINE HUNDRED AND SEVENTY FIVE), the said Mr. FEYNMAN has held a ‘responsible position.’” They had no disagreement about what that would mean:

For the purpose of the aforementioned WAGER, the term “responsible position” shall be taken to signify a position which, by reason of its nature, compels the holder to issue instructions to other persons to carry out certain acts, notwithstanding the fact that the holder has no understanding whatsoever of that which he is instructing the aforesaid persons to accomplish.

Feynman collected the ten dollars in 1976.

He already tried to avoid encumbrances as though every invitation, honor, professional membership, or knock at his door were another vine wrapping itself around his creative center. By the time he won the Nobel Prize he had been trying for five years to resign from the National Academy of Sciences. This simple task was taking on a life of its own. He began by scribbling a note with his dues bill: he paid the forty dollars, but he resigned. Almost a year later he received a personal letter from the academy’s president, the biologist Detlev W. Bronk (whose original paper on the single nerve impulse he had read as a Princeton student). He felt obliged to write a polite explanation:

My desire to resign is merely a personal one; it is not meant as a protest of any kind… . My peculiarity is this: I find it psychologically very distasteful to judge people’s “merit.” So I cannot participate in the main activity of selecting people for membership. To be a member of a group, of which an important activity is to choose others deemed worthy of membership in that self-esteemed group, bothers me… .

Maybe I don’t explain it very well, but suffice to say that I am not happy as a member of a self-perpetuating honorary society.

It was 1961. Bronk let Feynman’s letter sit for months. Then he answered with calculated obtuseness:

Thank you for your willingness to continue as a member of the academy… . I have done my best to reduce the emphasis on the “honor” of election… . I am grateful that you will continue a member at least during my last year as president.

Eight years later, Feynman was still trying. He re-resigned. A reply came from the president-elect, Philip Handler, who mused talmudically, “I suppose that we truly have no alternative, in the sense that surely the Academy must adhere to your wishes,” and deftly slid Feynman’s resignation into the subjunctive mood:

I would consider your resignation a most sorrowful event indeed… . I write to hope that you will reconsider… . I am reluctant to endorse such an action… . Before processing your request, a procedure for which I trust that the Office of the Home Secretary is in some manner prepared, I very much hope that you will let us hear from you further… .

Feynman wrote again, as plainly as he could. Handler replied:

I have your somewhat cryptic note… . We are seeking to increase the meaningful roles of the Academy… . Wouldn’t you rather join us in that effort?

Finally, by 1970, Feynman’s resignation began to seem real even to the academy, though he continued to hear from scientists who wondered whether he would confirm the rumor and explain why.

He turned down honorary degrees offered by the University of Chicago and by Columbia University and thus finally kept the promise he had made to himself on the day he received his doctorate from Princeton. He turned down hundreds of other propositions with a curtness that impressed even his protective secretary. To a book publisher who had invited him to “introduce a draft of fresh air into a rather stuffy area,” he wrote: “No sir. The area is stuffy from too much hot air already.” He refused to sign petitions and newspaper advertisements; the Vietnam War was now drawing the opposition of many scientists, but he would not join them publicly. Feynman, Nobel laureate, found that even canceling a magazine subscription took an entire correspondence. “Dear Professor Feynman,” began a long letter from the editor of Physics Today, the magazine whose second issue had carried his article about the Pocono conference in 1948:

The comment you sent back with our questionnaire on our May issue (“I never read your magazine. I don’t know why it is published. Please take me off your mailing list. I don’t want it.”) poses some interesting questions for us… .

Four hundred words later, the editor had not given up:

I apologize for asking any more of your time, but all of us at Physics Today will appreciate it very much if we can have amplification of your earlier comments.

So Feynman amplified:

Dear Sir,

I’m not “physicists,” I’m just me. I don’t read your magazine so I don’t know what’s in it. Maybe it’s good, I don’t know. Just don’t send it to me. Please remove my name from the mailing list as requested. What other physicists need or don’t need, want or don’t want, has nothing to do with it… . It was not my intention to shake your confidence in your magazine—nor to suggest that you stop publication—only that you stop sending it here. Can you do that please?

He was hardening his shell. He knew he could seem cold. His secretary, Helen Tuck, protected him, sometimes sending away visitors while Feynman hid behind her door. Or he would just shout at a hopeful student to go away—he was working. He almost never participated in the business of his department at Caltech: tenure decisions, grant proposals, or any of the other administrative chores that constitute overhead on most scientists’ time. Caltech’s divisions, like the science departments at every American university, were largely financed through a highly structured process of applications to the Department of Energy, the Department of Defense, and other government agencies. There were group applications and individual applications, supporting salaries, students, equipment, and overhead. At Caltech a senior professor who could arrange to have the air force, for example, pay a portion of his salary was rewarded with a discretionary kitty with which he could travel, buy a computer, or support a graduate student. Alone at Caltech, and virtually alone in physics, Feynman was humored in his refusal to participate in this process. To some colleagues he seemed selfish. It occurred to the historian of science Gerald Holton, however, that Feynman had put on a kind of hair shirt. “It must have been very difficult to live that way,” Holton said. “It does not come easy to make that conscious decision to remain unadulterated. Culture by definition is very seductive. He was a Robinson Crusoe in the big city, and that isn’t easy to do.” I. I. Rabi once said that physicists are the Peter Pans of the human race. Feynman clutched at irresponsibility and childishness. He kept a quotation from Einstein in his files about the “holy curiosity of inquiry”: “this delicate little plant, aside from stimulation, stands mainly in need of freedom; without this it goes to wrack and ruin without fail.” He protected his freedom as though it were a dying candle in a hard wind. He was willing to risk hurting his friends. Hans Bethe turned sixty the year after Feynman won his Nobel Prize, and Feynman refused to send a contribution to the customary volume of articles in his honor.

He was frightened. In the years after the prize he felt uncreative. His Caltech colleague David Goodstein traveled with him to the University of Chicago when he went to address the undergraduates there early in 1967. Goodstein thought he seemed depressed and worried. When Goodstein came down to breakfast at the faculty club, he found Feynman already there, talking with someone who Goodstein gradually realized was the codiscoverer of DNA, James Watson. Watson gave Feynman a manuscript tentatively titled Honest Jim. It was a tame memoir by later standards, but when it was published—under a different title, The Double Helix—it caused an enormous popular stir. With a candor that shocked many of Watson’s colleagues, it portrayed the ambition, the competitiveness, the blunders, the miscommunications, and the raw excitement of real scientists. Feynman read it in his room at the Chicago faculty club, skipping the cocktail party in his honor, and found himself moved. Later he wrote Watson:

Don’t let anybody criticize that book who hasn’t read it through to the end. Its apparent minor faults and petty gossipy incidents fall into place as deeply meaningful… . The people who say “that is not how science is done” are wrong… . When you describe what went on in your head as the truth haltingly staggers upon you and passes on, finally fully recognized, you are describing how science isdone. I know, for I have had the same beautiful and frightening experience.

Late that night in Chicago he startled Goodstein by pressing the book into his hands and telling him he had to read it. Goodstein said he would look forward to it. No, Feynman said. You have to read it now. So Goodstein did, turning pages until dawn as Feynman paced nearby or sat and doodled on a sheet of paper. At one point Goodstein remarked, “You know, it’s amazing that Watson made this great discovery even though he was so out of touch with what everyone in his field was doing.”

Feynman held up the paper he had been writing on. Amid scribbling and embellishments he had inscribed one word: DISREGARD.

“That’s what I’ve forgotten,” he said.

Quarks and Partons

In 1983, looking back on the evolution of particle physics since the now-historic Shelter Island conference, Murray Gell-Mann said, uncontroversially, that he and his colleagues had developed a theory that “works.” He summed it up in one intricately crafted sentence (rather more refined than “All things are made of atoms …”):

It is of course a Yang-Mills theory, based on color SU(3) and electroweak SU(2) U(1), with three families of spin ½ leptons and quarks, their antiparticles, and some spinless Higgs bosons in doublets and antidoublets of the weak isotopic spin to break the electroweak group down to U1 of electromagnetism.

His listeners recognized vintage Gell-Mann, from the “of course” onward. For aficionados there was a poetry in the jargon, much of which Gell-Mann had invented personally. He loved language more than ever. As always, during the next hour he punctuated his physics with a stream of abstruse and punning nomenclatural asides: “By the way, some people have called the higglet by another name [holds up a box of Axion laundry presoak], in which case it’s extremely easy to discover in any supermarket”; “… many physicists—Dimopoulos, Nanopoulos, and Iliopoulos, and for the benefit of my French friends I add Rastopopoulos”; “… O’Raifertaigh. (His name, by the way, is written in a simplified manner; the ‘f’ should really be ‘thbh’)”; and so on.

Some people found his style irritating—among them, those whose names he tried to correct—but that was a minor detail. Gell-Mann, more than any other physicist of the sixties and seventies, defined the mainstream of the physics that Feynman had reminded himself to disregard. In so many ways these two scientific icons had come to seem like polar opposites—the Adolphe Menjou and Walter Matthau of theoretical physics. Gell-Mann loved to know things’ names and to pronounce them correctly—so correctly that Feynman would misunderstand, or pretend to misunderstand, when Gell-Mann uttered so simple a name as Montreal. Gell-Mann’s conversational partners often suspected that the obscure pronunciations and cultural allusions were designed to place them at a disadvantage. Feynman pronounced potpourri “pot-por-eye” and interesting as if it had four syllables, and he despised nomenclature of all kinds. Gell-Mann was an enthusiastic and accomplished bird-watcher; the moral of one of Feynman’s classic stories about his father was that the name of a bird did not matter, and the point was hardly lost on Gell-Mann.

Physicists kept finding new ways to describe the contrast between them. Murray makes sure you know what an extraordinary person he is, they would say, while Dick is not a person at all but a more advanced life form pretending to be human to spare your feelings. Murray was interested in almost everything—but not the branches of science outside high-energy physics; he was openly contemptuous of those. Dick considered all science to be his territory—his responsibility—but remained brashly ignorant of everything else. Some well-known physicists resented Feynman for his cherished irresponsibility—it was, after all, irresponsibility to his academic colleagues. A larger number disliked Gell-Mann for his arrogance and his sharp tongue.

There was always more. Dick wore shirtsleeves, Murray wore tweed. Murray ate at the Atheneum, the faculty club, while Dick ate at “the Greasy,” the cafeteria. (This was only half true. Either man could be found at either place on occasion, although Feynman, when the Atheneum still required ties and jackets, would show up in shirtsleeves and demand the most garish and ill-fitting of the spare items kept on hand for emergencies.) Feynman talked with his hands—with his whole body, in fact—whereas Gell-Mann, as the physicist and science writer Michael Riordan observed, “sits calmly behind his desk in a plush blue swivel chair, hands folded, never once lifting them to make a gesture… . Information is exchanged by words and numbers, not by hands or pictures.” Riordan added:

Their personal styles spill over into their theoretical work, too. Gell-Mann insists on mathematical rigor in all his work, often at the expense of comprehensibility… . Where Gell-Mann disdains vague, heuristic models that might only point the way toward a true solution, Feynman revels in them. He believes that a certain amount of imprecision and ambiguity is essential to communication.

Yet they were not so different in their approach to physics. Those who knew them best as physicists felt that Gell-Mann was no more likely than Feynman to hide behind formalism or to use mathematics as a stand-in for physical understanding. Those who considered him pretentious about language and cultural trivia felt nonetheless that when it came to physics he was as honest and direct as Feynman. Over a long career Gell-Mann made his vision not only comprehensible but irresistible. Both men were relentless on the trail of a new idea, able to concentrate absolutely, willing to try anything.

Both men, it seemed to a few perceptive colleagues, presented a mask to the world. “Murray’s mask was a man of great culture,” Sidney Coleman said. “Dick’s mask was Mr. Natural—just a little boy from the country that could see through things the city slickers can’t.” Both men filled their masks until reality and artifice became impossible to pry apart.

Gell-Mann, as naturalist, collector, and categorizer, was well primed to interpret the exploding particle universe of the 1960s. New technology in the accelerators—liquid hydrogen bubble chambers and computers for automating the analysis of collision tracks—seemed to have spilled open a bulky canvas bag from which nearly a hundred distinct particles had now tumbled forth. Gell-Mann and, independently, an Israeli theorist, Yuval Ne’eman, found a way in 1961 to organize the various symmetries of spins and strangeness into a single scheme. It was a group, in the mathematicians’ sense of the word, known as SU(3), though Gell-Mann quickly and puckishly dubbed it the Eightfold Way. It was like an intricate translucent object which, when held to the light, would reveal families of eight or ten or possibly twenty-seven particles—and they would be different, though overlapping, families, depending on which way one chose to view it. The Eightfold Way was a new periodic table—the previous century’s triumph in classifying and thus exposing the hidden regularities in a similar number of disparate “elements.” But it was also a more dynamic object. The operations of group theory were like special shuffles of a deck of cards or the twists of a Rubik’s cube.

Much of SU(3)’s power came from the way it embodied a concept increasingly central to the high-energy theorist’s way of working: the concept of inexact symmetry, almost symmetry, near symmetry, or—the term that won out—broken symmetry. The particle world was full of near misses in its symmetries, a dangerous problem, since it seemed to permit an ad hoc escape route whenever an expected relationship failed to match. Broken symmetry implied a process, a change in status. A symmetry in water is broken when it freezes, for now the system does not look the same from every direction. A magnet embodies symmetry breaking, since it has made a kind of choice of orientation. Many of the broken symmetries of particle physics came to seem like choices the universe made when it condensed from a hot chaos into cooler matter, spiked as it is with so many hard-edged, asymmetrical contingencies.

Once again Gell-Mann trusted his scheme enough to predict, as a consequence of broken symmetry, a specific hitherto-unseen particle. This, the omega minus, duly turned up in 1964—a thirty-three-experimenter team had to canvass more than one million feet of photographs—and Gell-Mann’s Nobel Prize followed five years later.

His next, most famous invention came in an effort to add explanatory understanding to the descriptive success of the Eightfold Way. SU(3) should have had, along with its various eight-member and ten-member and other families, a most-basic three-member family. This seemed a strange omission. Yet the rules of the group would have required this threesome to carry fractional electric charges: ? and - ?. Since no particle had ever turned up with anything but unit charge, this seemed implausible even by modern standards. Nevertheless, in 1963 Gell-Mann and, independently, a younger Caltech theorist, George Zweig, proposed it anyway. Zweig called his particles aces. Gell-Mann won the linguistic battle once again: his choice, a croaking nonsense word, was quark. (After the fact, he was able to tack on a literary antecedent when he found the phrase “Three quarks for Muster Mark” in Finnegans Wake, but the physicist’s quark was pronounced from the beginning to rhyme with “cork.”)

It took years for Gell-Mann and other theorists to generate all the contrivances needed to make quarks work. One contrivance was a new property called color—purely artificial, with no connection to everyday color. Another was flavor: Gell-Mann decided that the flavors of quarks would be called up, down, and strange. There had to be antiquarks and anticolors. A new mediating particle called the gluon would have to carry color from one quark to another. All this encouraged skepticism among physicists. Julian Schwinger wrote that he supposed such particles would be detected by “their palpitant piping, chirrup, croak, and quark.” Zweig, far more vulnerable than Gell-Mann, felt that his career was damaged. The quark theorists had to wrestle with the fact that their particles never appeared anywhere, though people did begin a dedicated search in particle accelerators and supposed cosmic-ray deposits in undersea mud.

There was a reality problem, distinctly more intense than the problem posed by more familiar entities such as electrons. Zweig had a concrete, dynamical view of quarks—too mechanistic for a community that had learned as far back as Heisenberg to pay attention only to observables. Gell-Mann’s comment to Zweig was, “The concrete quark model—that’s for blockheads.” Gell-Mann was wary of the philosophical as well as the sociological problem created by any assertion one way or the other about quarks being real. For him quarks were at first a way of making a simple toy field theory: he would investigate the theory’s properties, abstract the appropriate general principles, and then throw away the theory. “It is fun to speculate about the way quarks would behave if they were physical particles of finite mass (instead of purely mathematical entities as they would be in the limit of infinite mass),” he wrote. As if they were physical particles; then again, as if they were conveniences of mathematics. He encouraged “a search for stable quarks”—but added with one more twist that it “would help reassure us of the nonexistence of real quarks.” His initial caveats were quoted by commentators again and again in the years that followed. One physicist’s typically uncharitable interpretation: “I always considered that to be a coded message. It seemed to say, ‘If quarks are not found, remember I never said they would be; if they are found, remember I thought of them first.’” For Gell-Mann this became a permanent source of bitterness.

Feynman, meanwhile, had disregarded so much of the decade’s high-energy physics that he had to make a long-term project of catching up. He tried to pay more attention to experimental data than to the methods and language of theorists. He tried, as always, to read papers only until he understood the issue and then to work out the problem for himself. “I’ve always taken an attitude that I have only to explain the regularities of nature—I don’t have to explain the methods of my friends,” he told a historian during these years. He did manage to avoid some passing fashions. Still, he was turning back to a community after having drifted outside, and he had to learn its shared methods after all. It was no longer possible to approach these increasingly formidable, specialized problems as an outsider. He had stopped teaching high-energy physics; in the late sixties he began again. At first his syllabus contained no quarks.

By the late sixties and early seventies a new accelerator embedded in the rolling hills near Stanford University in northern California had taken the dominant role in the strong-interaction experiments that were so central to the search for quarks. The Stanford Linear Accelerator Center (SLAC) made a straight two-mile cut in the grassy landscape. Aboveground, cows grazed and young physicists in jeans and shirts—nearly a hundred of them—sat at picnic tables or walked in and out of the center’s many buildings. Below, inside a knife-straight evacuated copper tube, a beam of electrons streamed toward targets of protons. The electrons achieved energies far greater than theorists had ever had to manage. They struck their targets inside an end station like a giant airplane hangar and then, with luck, entered a detector inside a concrete blockhouse, lined with lead bricks, riding on railroad tracks and angled upward toward the ceiling. Sometimes high-speed motion-picture cameras recorded the results, and elsewhere in the laboratory teams of human scanners guided an automatic digitizer that could read the particle tracks from—for a given monthlong experiment—hundreds of millions of filmed images. A single bubble chamber at the end of the particle beam, in its five-and-a-half-year useful lifetime, saw the discovery of seventeen new particles.

It was a tool for exploring the strong force—so called because, at the very short distances in the domain of the nucleus, it must dominate the force of electromagnetic repulsion to bind protons and neutrons (hadron was now the general term for particles that felt the strong force). Feynman had been thinking about how to understand the working of the strong force in collisions of hadrons with other hadrons. These were complex: at the high energies now available for studying short distances, hadron-hadron collisions produced gloriously messy sprays of detritus. The hadrons themselves were neither simple nor pointlike. They had size, and they seemed to have internal constituents—a whole swarming zoo of them. As Feynman said, the hadron-hadron work was like trying to figure out a pocket watch by smashing two of them together and watching the pieces fly out. He began visiting SLAC regularly in the summer of 1968, however, and saw how much simpler was the interaction offered by electron-proton collisions, the electron tearing through the proton like a bullet.

He stayed with his sister; she had moved to the Stanford area to work for a research laboratory, and her house was just across Sand Hill Road from the accelerator center. The physicists who would gather on the outdoor patio to listen to his stories that summer would see him slamming his open hands together in a boisterous illustration of a new idea he had. He was talking about “pancakes”—flat particle pancakes with hard objects embedded in them.

The Caltech connection was important to experimenters at SLAC, and by the late sixties the connection meant Gell-Mann far more than Feynman. Gell-Mann had created the scientific subculture of current algebra, the mathematical framework surrounding his quarks, and SLAC theorists thought of themselves as trying to generalize these tools to smaller distances, higher energies. At accelerators like SLAC, most of the thinking focused on the simplest reactions—two particles in, two particles out—although most of the actual collisions produced enormous flashes of many more particles. Experimenters wanted the most precise possible data, and precision was impossible in these bursts of detritus. Feynman chose a different point of view. He introduced a formalism in which one could look at the distributions of twenty or fifty or more particles. One did not have to be able to measure the momentum of each particle; in effect one could sum over all the possibilities. A Stanford theorist, James D. Bjorken, had been thinking along similar lines. An electron hits a proton; an electron comes out, along with a burst of immeasurable fragments. The emerging electron was a common factor. Bjorken decided to set aside the miscellaneous spray and simply plot the distribution of the energies and angles of the emerging electrons, averaged over many collisions.

He isolated a remarkable regularity in the data, a phenomenon he called “scaling”—the data looked the same at different energy scales. He did not know just how to interpret this. He had a variety of guesses, most framed in the language of current algebra. When Feynman arrived, Bjorken happened to be away; Feynman saw the graphed data without hearing a clear explanation of its origin. He suddenly recognized it, however, and he calculated long into the evening. It could be viewed as a graph of his pancake theory, the theory he had been toying with all summer on his own.

He had decided to cut through the incalculable swarming muddle of proton pieces by positing a mysterious new constituent that he called a parton, a name based inelegantly on the word part. (Finally he had an entry of his own in the Oxford English Dictionary.) Feynman made almost no assumptions about his partons except two: they were pointlike, and they did not interact meaningfully with one another but floated freely about inside the proton. They were an abstraction—just the kind of unobservable entity that physicists hoped not to have to fall back on—yet they were tantalizingly visual in spirit. They were pegs on which to hang a field theory of the old, manageable sort, with wave functions and calculable probability amplitudes. By analogy, quantum electrodynamics had its partons, too: the bare electrons and photons.

Feynman showed that collisions with these hard nuggets inside the proton would produce the scaling relations in a natural manner, unlike collisions with the puffy whole proton. He chose not to decide what quantum numbers they did or did not carry, and he most emphatically decided not to worry one way or the other about whether his partons were the fractionally charged quarks of Gell-Mann and Zweig.

By the time Bjorken returned, he found the theory group awash in partons. Feynman buttonholed him. He had idolized Feynman ever since taking an old-fashioned, historically organized quantum electrodynamics course at Stanford. “When Feynman diagrams arrived,” he said, “it was the sun breaking through the clouds, complete with rainbow and pot of gold. Brilliant! Physical and profound!” Now here was Feynman in the flesh, explaining Bjorken’s own theory to him with a new language and a new visual image. As he could instantly see, Feynman’s essential insight was to place himself once again in the electron, to see what the electron would see at light speed. He would see the protons flashing toward him—and they were therefore flattened relativistically into pancakes. Relativity also slowed their internal clocks, in effect, and, from the electron’s point of view, froze the partons into immobility. His scheme reduced the messy interaction of an electron with a fog of different particles to a much simpler interaction of an electron with a single pointlike parton emerging from the fog. Bjorken’s scaling pattern flowed directly from the physics of this picture. The experimenters grasped it instantly.

The parton model was oversimplified. It explained nothing that Bjorken could not explain, although Bjorken’s explanation seemed less fundamental. Partons required considerable hand-waving. Yet physicists clutched at them like a lifeboat. Three years passed before Feynman published a formal paper and many more before his partons finally and definitively blended with quarks in the understanding of physicists.

Zweig’s aces, Gell-Mann’s quarks, and Feynman’s partons became three paths to the same destination. These constituents of matter served as the quanta of a new field, finally making possible a field theory of the strong force. Quarks had not been seen or detected in the direct fashion of more venerable particles. They became real nonetheless. Feynman took on a project in 1970 with two students, assembling a vast catalog of particle data in an effort to make a judgment about whether a simple quark model could underlie it all. He chose an unconventional model once again, using data that let him think in terms of the electromagnetic field theory of the last generation, instead of the hadron-collision data that interested most theorists. For whatever reason, he was persuaded—converted into a quarkerian, as he said—although he continued to stress the tentativeness of any one model. “A quark picture may ultimately pervade the entire field of hadron physics,” this paper concluded. “About the paradoxes of the quark model we have nothing to add, except perhaps to make these paradoxes more poignant by exhibiting the mysteriously good fit of a peculiar model.” Younger theorists learned how to explain confinement—the quark’s inability to appear as free particles—in terms of a force that grew rapidly with distance, in strange contrast to forces such as gravity and electromagnetism. Quarks became real not only because ingenious experiments gave an indirect look at them, but because it became harder and harder for theorists to construct a coherent model in which they did not figure. They became so real that Gell-Mann, their inventor, had to endure the after-the-fact criticism that he had not fully believed in them. He never understood why Feynman had created his own alternative quark and maintained a distinction that faded in the end. He missed no opportunity to call Feynman’s particles “put-ons.” Like Schwinger years before, he disliked the fanfare over a picture that he thought was oversimplified—anyone could use it.

Quarks were real, at least to physicists of the last years of this century. Partons were not, in the end. What is real? Feynman tried to keep this question from disappearing into the background. In a book assembled from his lectures, Photon-Hadron Interactions, he concluded:

We have built a very tall house of cards making so many weakly based conjectures one upon the other… . Even if our house of cards survives and proves to be right we have not thereby proved the existence of partons… . On the other hand, the partons would have been a useful psychological guide … and if they continued to serve this way to produce other valid expectations they would of course begin to become “real,” possibly as real as any other theoretical structure invented to describe nature.

Once again Feynman had placed himself at the center of modern theoretical physics. His language, his framework, dominated high-energy physicists’ discourse for several years. He wanted to move on again, or so he told himself. “I’m a little bit frustrated,” he said to a historian soon after he published his first parton paper.

I’m tired of thinking of the same thing. I need to think of something else. Because I got stuck—see, if it would keep going it would be all right, but it’s hard to get any new results… . This parton thing has been so successful that I have become fashionable. I have to find an unfashionable thing to do.

Feynman routinely refused to recommend colleagues for the Nobel Prize, but he broke his rule in 1977—after Gell-Mann had already won the prize once—and quietly nominated Gell-Mann and Zweig for their invention of quarks.

Teaching the Young

RICHARD. [Humming softly to himself] Jee-jee-jee-ju-ju. Jee-jee-jee-ju-ju. [He is working. Dishes are being cleared from the breakfast table. A tape recorder makes a faint whirr as it eavesdrops: a friend has taken to leaving it running in hopes of capturing stories about Feynman’s past.] Jee-jee-jee-ju-ju. [Stops abruptly.] There’s some fool has made a mistake here. Some damn fool made a mistake here.

MICHELLE. Prob’ly you.

RICHARD. Me? What do you mean, me? [Pause.] Some idiot has made an error. [Sings] I have an idiot here who made an error.

MICHELLE. Yeah—you!

RICHARD. Michelle, dear, be careful what you say. After all your father is a nice fellow and he doesn’t want that kind of trouble. [Pause.] He’s made a mis-too-ko. You know, mistookos happen. You know. You don’t want your daddy to be a bad boy. [Drums a sharp tattoo with his fingers.] That is of course wrong! As any fool can see.

It took years for Feynman’s children to realize that their father was not like other fathers. He seemed normally distracted, lounging in his dog-chewed recliner or lying on the floor, writing on notepads, humming to himself in flights of concentration that were hard to break through. He doted on them and told them fantastically imaginative stories. In one ongoing saga they became tiny inhabitants of a gigantic household world; Feynman would describe the forest of brown leafless trees rising around them, for example, until suddenly they would guess that those were the fibers of the carpet. Or he would hold them on his lap and say, “What do you know about? You know about concrete and you know about rubber and you know about glass …” He taught them what he considered the basics of economics: that when prices go up, people buy less; that manufacturers set prices to maximize profits; that economists know very little. There were times when they thought he had been placed on earth mainly to embarrass them in public—pretending to beat them about the head with a newspaper or talking to waiters in his mock Italian. He was always what Michelle thought of as borderline boisterous, singing and whistling to himself. He would make up rhymes under his breath as he walked around the house—“I’m going to pick up my shoe, that’s what I’m going to do”—and when challenged he would be unable to repeat what he had just said. Belatedly it dawned on them that not all their friends could look up their fathers in the encyclopedia. His own mother was still alive, and he seemed to revert to a child in her presence. Lucille would say, “Richard, I’m cold—would you please put on a sweater?” When Omni magazine called him the world’s smartest man, she remarked, “If that’s the world’s smartest man, God help us.”

Carl showed an early gift for science, to Feynman’s immense delight. When he was twelve, Feynman showed him an odd-looking photograph he had brought home from a Canadian laboratory and Carl guessed—correctly—that it was “probably a diffraction pattern from a laser from a regular pattern of square holes,” and Feynman could not help boasting to a friend, “I could have killed him—I was afraid to ask him for the focal length of the lens used!” He tried not to prod too clumsily, and he told himself that he would be happy with any careers his children chose (“trumpet playing—social worker—zygophalatelist—or whatever,” he wrote Carl), as long as they were happy and good at what they did. When Carl reached college, however—MIT—he found the one career ambition guaranteed to break his father’s equilibrium. “Well,” Feynman wrote, “after much effort at understanding I have gradually begun to accept your decision to become a philosopher.” But he hadn’t. He felt as betrayed and put upon as a business executive whose child wants to be a poet.

I find myself asking, “How can you be a good philosopher?” I see now that, like the poet son who never thinks of money (because he expects his old man to pay) you have chosen philosophy, over clear thought (and so your old man goes on with his clear thoughts) so that you can fly above common sense to far higher and more beautiful aspects of the intellect.

“Well,” he added sarcastically, “it must be wonderful to be able to do that.” Educating his children made him think again about the elements of teaching and about the lessons his own father had taught. By the time Carl was four, Feynman was actively lobbying against a first-grade science book proposed for California schools. It began with pictures of a mechanical wind-up dog, a real dog, and a motorcycle, and for each the same question: “What makes it move?” The proposed answer—“Energy makes it move”—enraged him.

That was tautology, he argued—empty definition. Feynman, having made a career of understanding the deep abstractions of energy, said it would be better to begin a science course by taking apart a toy dog, revealing the cleverness of the gears and ratchets. To tell a first-grader that “energy makes it move” would be no more helpful, he said, than saying “God makes it move” or “moveability makes it move.” He proposed a simple test for whether one is teaching ideas or mere definitions:

You say, “Without using the new word which you have just learned, try to rephrase what you have just learned in your own language. Without using the word energy, tell me what you know now about the dog’s motion.”

Other standard explanations were just as hollow: gravity makes it fall, or friction makes it wear out. Having tried to impart fundamental knowledge to Caltech freshmen, he also believed it was possible to teach real knowledge to first-graders. “Shoe leather wears out because it rubs against the sidewalk and the little notches and bumps on the sidewalk grab pieces and pull them off.” That is knowledge. “To simply say, ‘It is because of friction,’ is sad, because it’s not science.”

Feynman taught thirty-four formal courses during his Caltech career, roughly one a year. Most were graduate seminars called Advanced Quantum Mechanics or Topics in Theoretical Physics. That often meant his current research interest: graduate students sometimes heard, without realizing it, the first and last report of substantial work that another physicist would have published. For almost two decades he also taught a course, listed in no catalog, known as Physics X: one afternoon a week, undergraduates would gather to pose any scientific question they wished, and Feynman would improvise. His effect on these students was immense; they often left the Lauritsen Laboratory basement feeling that they had had a private pipeline to an oracle with an earthy kind of omniscience. He believed—in the face of the increasing esotericism of his own subject—that true understanding implied a kind of clarity. A physicist once asked him to explain in simple terms a standard item of the dogma, why spin-one-half particles obey Fermi-Dirac statistics. Feynman promised to prepare a freshman lecture on it. For once, he failed. “I couldn’t reduce it to the freshman level,” he said a few days later, and added, “That means we really don’t understand it.”

It was his own children, however, who crystallized many of his attitudes toward teaching. In 1964 he had made the rare decision to serve on a public commission, responsible for choosing mathematics textbooks for California’s grade schools. Traditionally this commissionership was a sinecure that brought various small perquisites under the table from textbook publishers. Few commissioners—as Feynman discovered—read many textbooks, but he determined to read them all, and had scores of them delivered to his house. This was the era of the so-called new mathematics in children’s education: the much-debated effort to modernize the teaching of mathematics by introducing such high-level concepts as set theory and nondecimal number systems. New math swept the nation’s schools startlingly fast, in the face of parental nervousness that was captured in a New Yorker cartoon: “You see, Daddy,” a little girl explains, “this set equals all the dollars you earned; your expenses are a sub-set within it. A sub-set of that is your deductions.”

Feynman did not take the side of the modernizers. Instead, he poked a blade into the new-math bubble. He argued to his fellow commissioners that sets, as presented in the reformers’ textbooks, were an example of the most insidious pedantry: new definitions for the sake of definition, a perfect case of introducing words without introducing ideas. A proposed primer instructed first-graders: “Find out if the set of the lollipops is equal in number to the set of the girls.” Feynman described this as a disease. It removed clarity without adding any precision to the normal sentence: “Find out if there are just enough lollipops for the girls.” Specialized language should wait until it is needed, he said, and the peculiar language of set theory never is needed. He found that the new textbooks did not reach the areas in which set theory does begin to contribute content beyond the definitions: the understanding of different degrees of infinity, for example.

It is an example of the use of words, new definitions of new words, but in this particular case a most extreme example because no facts whatever are given… . It will perhaps surprise most people who have studied this textbook to discover that the symbol ? or ? representing union and intersection of sets … all the elaborate notation for sets that is given in these books, almost never appear in any writings in theoretical physics, in engineering, business, arithmetic, computer design, or other places where mathematics is being used.

Feynman could not make his real point without drifting into philosophy. It was crucial, he argued, to distinguish clear language from precise language. The textbooks placed a new emphasis on precise language: distinguishing “number” from “numeral,” for example, and separating the symbol from the real object in the modern critical fashion—pilpul for schoolchildren, it seemed to Feynman. He objected to a book that tried to teach a distinction between a ball and a picture of a ball—the book insisting on such language as “color the picture of the ball red.”

“I doubt that any child would make an error in this particular direction,” Feynman said dryly.

As a matter of fact, it is impossible to be precise … whereas before there was no difficulty. The picture of a ball includes a circle and includes a background. Should we color the entire square area in which the ball image appears all red? … Precision has only been pedantically increased in one particular corner when there was originally no doubt and no difficulty in the idea.

In the real world, he pointed out once again, absolute precision is an ideal that can never be reached. Nice distinctions should be reserved for the times when doubt arises.

Feynman had his own ideas for reforming the teaching of mathematics to children. He proposed that first-graders learn to add and subtract more or less the way he worked out complicated integrals—free to select any method that seems suitable for the problem at hand. A modern-sounding notion was, The answer isn’t what matters, so long as you use the right method. To Feynman no educational philosophy could have been more wrong. The answer is all that does matter, he said. He listed some of the techniques available to a child making the transition from being able to count to being able to add. A child can combine two groups into one and simply count the combined group: to add 5 ducks and 3 ducks, one counts 8 ducks. The child can use fingers or count mentally: 6, 7, 8. One can memorize the standard combinations. Larger numbers can be handled by making piles—one groups pennies into fives, for example—and counting the piles. One can mark numbers on a line and count off the spaces—a method that becomes useful, Feynman noted, in understanding measurement and fractions. One can write larger numbers in columns and carry sums larger than 10.

To Feynman the standard texts seemed too rigid. The problem 29 + 3 was considered a third-grade problem, because it required the advanced technique of carrying; yet Feynman pointed out that a first-grader could handle it by thinking 30, 31, 32. Why should children not be given simple algebra problems (2 times what plus 3 is 7?) and encouraged to solve them by trial and error? That is how real scientists work.

We must remove the rigidity of thought… . We must leave freedom for the mind to wander about in trying to solve the problems… . The successful user of mathematics is practically an inventor of new ways of obtaining answers in given situations. Even if the ways are well known, it is usually much easier for him to invent his own way—a new way or an old way—than it is to try to find it by looking it up.

Better to have a jumbled bag of tricks than any one orthodox method. That was how he taught his own children at homework time. Michelle learned that he had a thousand shortcuts; also that they tended to get her into trouble with her arithmetic teachers.

Do You Think You Can Last On Forever?

Although he had never liked athletic activity, he tried to stay fit. After he broke a kneecap falling over a Chicago curb, he took up jogging. He ran almost daily up and down the steep paths above his house in the Altadena hills. He owned a wet suit and swam often at the beachfront house in Mexico that he had bought with his Nobel Prize money. (It had been a shambles when he and Gweneth first saw it. He told her that they did not want it. She looked at the glass wall facing the warm currents sweeping up from the Tropic of Cancer and replied, “Oh yes, we do.”)

Traveling in the Swiss Alps in the summer of 1977, he frightened Gweneth by suddenly running to the bathroom of their cabin and vomiting—something he never did as an adult. Later that day he passed out in the téléphérique. Twice that year his physician diagnosed “fever of undetermined origin.” It was not until October 1978 that cancer was discovered: a tumor that had grown to the size of a melon, weighing six pounds, in the back of his abdomen. A bulge was visible at his waistline when he stood straight. He had ignored the symptoms for too long. He had had other worries: just months before, Gweneth had herself undergone surgery for cancer. Feynman’s tumor pushed his intestines aside and destroyed his left kidney, his left adrenal gland, and his spleen.

It was a rare cancer of the soft fat and connective tissue, a myxoid liposarcoma. After difficult surgery, he left the hospital looking gaunt and began a search of the medical literature. There he found no shortage of probabilistic estimates. The likelihood of a recurrent tumor was high, though his had appeared well encapsulated. He read a series of individual case studies, none with a tumor as large as his. “Five-year survival rates,” one journal said in summary, “have been reported from 0% to 11%, with one report of 41%.” Almost no one survived ten years.

He returned to work. “You are old, Father Feynman,” wrote a young friend in a mocking bit of verse,

“And your hair has turned visibly gray;

And yet you keep tossing ideas around—

At your age, a disgraceful display!”

“In my youth,” said the Master, as he shook his long locks,

“I took a great fancy to sketching;

I drew many diagrams, which most thought profound

While others thought just merely fetching.”

“Yes, I know,” said the youth, interrupting the sage,

“That you once were so awfully clever;

But now is the time for quark sausage with chrome.

Do you think you can last on forever?”

Younger physicists, including Gell-Mann, had already stepped aside from the research frontier, but Feynman turned to problems in quantum chromodynamics—the latest synthesis of field theories, so named because of the central role of quark color. With a postdoctoral student, Richard Field, he studied the very-high-energy details of quark jets. Other theorists had realized that the reason quarks never emerged freely was that they were confined by a force unlike those with which physics was familiar. Most forces diminished with distance—gravity and magnetism, for example. It seemed obvious that this must be so, but the opposite was true for quarks. When they were close together, the force between them was negligible; when they were drawn apart, the force grew extremely strong. Jets, as Feynman and Field understood them, were a by-product. In a high-energy collision, before a quark could be broken free of these bonds, the force would become so great that it would create new particles, pulling them into existence out of the vacuum in a burst traveling in the same direction—a jet.

At first Field met with Feynman one afternoon a week. Feynman did not realize that Field was spending almost every waking hour preparing for their meeting. Their work took the form of predictions in a language well suited to experimenters. It was not abstruse theory but a realistic guide to what experimenters should see. Feynman insisted that they calculate only experiments that had not yet been performed; otherwise, he said, they would not be able to trust themselves. Gradually they found that they were able to stay a few months ahead of the experiments and provide a useful framework. As the accelerators reached higher energies, jets of the kind Feynman and Field had described came into existence.

Theorists meanwhile continued to struggle with their understanding of quark confinement: whether quarks must always be confined under every circumstance and whether confinement could be derived naturally from the theory. Victor Weisskopf urged Feynman to work on this, too, by saying that all he could see in the literature was formal mathematics. “I don’t get any physics out of it. Why don’t you attack the problem? You are just the right guy for it and you would find the essential physical reasons why QCD confines the quarks.” Feynman made an original effort in 1981 to solve this problem analytically in a toy model of two dimensions. Quantum chromodynamics, as he noted, had become a theory of such internal complexity that usually even the fastest supercomputers could not generate specific predictions to compare with experiments. “QCD field theory with six flavors of quarks with three colors, each represented by a Dirac spinor of four components, and with eight four-vector gluons, is a quantum theory of amplitudes for configurations each of which is 104 numbers at each point in space and time,” he wrote. “To visualize all this qualitatively is too difficult.” So he tried removing a dimension. This turned out to be a blind alley, although the freshness of his approach kept the work on some theorists’ reading lists long after they had passed by its conclusions.

In September 1981 a tumor recurred, this time entwined about Feynman’s intestines. The doctors tried a combination of doxorubicin, radiation treatment, and heat therapy. Then he underwent his second major surgery. The radiation had left his tissues spongy. The surgery lasted fourteen and a half hours and involved what the physicians described euphemistically as a “vascular incident”—his aorta split. An emergency request for blood went out at Caltech and the Jet Propulsion Laboratory, and donors lined up. Feynman needed seventy-eight pints. When Caltech’s president, Marvin Goldberger, entered his hospital room afterward, Feynman said, “I’d rather be where I am than where you are” and added that he still was not going to do anything Goldberger asked. In visible pain, he entertained his hospital visitors with new stories. Before the operation, the surgeon, Donald Morton of the UCLA Medical Center, had appeared with a halo of residents and nurses. Feynman asked what his chances were. “It’s impossible to talk about the probability of a single event,” he recounted the surgeon as saying, and he replied, “From one professor to another, it is possible if it’s a future event.”

Caltech’s influence in physics had waned. It drew the same extraordinary collection of bright, naïve, gangly undergraduates, all assuming that they would be taking graduate courses by their junior years. The best graduate students, however, went elsewhere. The physics colloquium remained an institution—Feynman usually sitting like a magnet in the front row, capable of dominating every session, visitors knew, entertainingly or ruthlessly. He could reduce an unwary speaker to tears. He shocked colleagues by tearing the flesh off an elderly Werner Heisenberg, made the young relativist Kip Thorne physically ill—the stories reminded older physicists of Pauli (“ganz falsch”). Douglas Hofstadter, a pioneer in artificial intelligence, gave an unusual talk on the slippery uses of analogy. He began by asking the audience to name the First Lady of England, looking for such answers as Margaret Thatcher, Queen Elizabeth, or Denis Thatcher. “My wife,” came the cry from the front row. Why? “Because she’s English and she’s great.” Through the rest of his talk, it seemed to Hofstadter that Feynman continued heckling in the manner of the village idiot. He was no less an institution than ever, but the center of gravity of elementary particle physics had drifted eastward again, toward Harvard and Princeton and other universities. A combined theory of electromagnetism and weak interactions had led to the gauge theories that brought together the strong interactions under the same quantum-chromodynamical umbrella. This resurgence of quantum theory also brought a new appreciation of Feynman’s path integrals, because path integrals proved essential in quantizing the gauge theories. Feynman’s discovery now seemed not just a useful tool but an organizing principle at nature’s deepest levels. Yet he did not pursue the new implications of path integrals himself. At the forefront were such theorists as Steven Weinberg,

Abdus Salam, Sheldon Glashow, and younger colleagues who had seen neither Feynman nor Gell-Mann as the magnets they had once been. Caltech physicists, concerned about the loss of their department’s preeminence, sometimes blamed Feynman for not involving himself enough in hiring and Gell-Mann for involving himself too much.

Ever since his return to high-energy physics with his parton model, Feynman had been struggling against the pull of gray-eminence, elder-statesman status. In 1974 he replied unnecessarily to a standard departmental inquiry by writing a one-sentence memorandum: “I have not accomplished anything this year in the way of research!” Two years later, when a friend, Sidney Coleman, put him on the participant list for a quantum field theory conference sponsored by Werner Erhard’s est Foundation, Feynman summed up his ambivalence about his insider and outsider status by replying in Groucho Marx fashion:

What the hell is Feynman invited for? He is not up to the other guys and is doing nothing as far as I know. If you clean up the invitation list, to just the hard-core workers, I might begin to think about attending.

Coleman duly removed him from the list, and Feynman attended.

He was untroubled by the association with est’s vaguely humbug sixties-inspired self-improvement seminars, suffused though they were with the pseudoscientific jargon that he ordinarily despised—“another piece of evidence,” as Coleman had said, “that we are living in the Golden Age of Silliness.” Erhard’s organization and other postsixties institutions were attracted to quantum theory for what appeared—misleadingly—to be a mystical view of reality, reminiscent, they thought, of Eastern religions and anyway more intriguing than the old-fashioned view that things are more or less what they seem. Such organizations, struggling to emerge from the sixties as ongoing business enterprises, were attracted to quantum physicists for the respectability they could lend. Meanwhile, Feynman was drawn to Erhard and other “flaky people”—as Gweneth referred to some of his new friends—partly because curiosity and nonconformity had long been his own trademarks. The youth movements of the sixties had caught up with him. They had brought his own style into vogue—his tieless, pomp-free outlook, the persona that he and Carl privately spoke of as “aggressive dopiness.” He grew his graying hair in a long mane. As much as he reviled organized psychology for what he considered its slippery use of the forms and methods of experimental science, he loved the introspective, self-examining kind of psychology. He let not only Werner Erhard but also John Lilly, an aficionado of dolphins and sensory-deprivation tanks, befriend him. He tried to ignore what he called Lilly’s “mystic hokey-poke” but nonetheless submerged himself in his tanks in the hope of having hallucinations, just as he had tried so hard to observe his own dream states forty years before. Death was not far from his thoughts. He recovered the earliest childhood memories he could dredge from his mind. He tried marijuana and (he was more embarrassed about this) LSD. He listened patiently as Baba Ram Das, the former Richard Alpert of Harvard, author of the cult book Be Here Now, instructed him on how to attain out-of-body experiences. He practiced these—OBE’s, in the current jargon—not willing to believe any of the mystical paraphernalia but happy and interested to imagine his ego floating here or there, outside himself, outside the room, outside the sixty-five-year-old body that was failing him so grievously.

Physicists did not make natural hippies. They had played too great a role in creating the technology-worshiping, nuclear-shadowed culture against which the counterculture set itself. When Feynman spoke now about his experience in the Manhattan Project, he stressed more than ever his cracking of safes and baiting of censors. He was more a rebel than an ambitious and effective group leader. Other people, “people in higher echelons,” made the decisions, he said, prefacing a 1975 talk at Santa Barbara. “I worried about no big decisions. I was always flittering about underneath.” He was hardly an enemy of technology; nor, despite his distaste for the bureaucracy of science, was he an enemy of what was now called the military-industrial complex. He had always refused to attach his name to Caltech’s grant proposals to the federal funding agencies that kept all university physics departments solvent. Still, he would emerge from Lilly’s sensory-deprivation tank, rinse off the Epsom salts in the shower, dress, and drive over to Hughes Aircraft Company, a military contractor, to deliver lectures on physics. He was not guarding his time as he had in the past. Sporadically, he worked for Hughes and several other companies as a consultant; he advised Hughes on a neural-net project sponsored by the Department of Defense and consulted with 3M Company engineers on nonlinear optical materials. For less than four hours of conversation he earned fifteen hundred dollars. These were scattered jobs, chosen with no special thought. Many of his colleagues arranged their consulting far more carefully and earned far more money. Feynman’s clients often seemed more grateful for the thrill of meeting him than for any particular technical contribution he made. He knew he was no businessman. He was Caltech’s highest paid professor, along with Gell-Mann; but Caltech kept all the royalties from The Feynman Lectures on Physics. When his old friend Philip Morrison sent him an advertisement for “seventeen towering lectures by two physics giants,” available from Time-Life Films, he wondered whether Morrison received any royalties. “I don’t,” Feynman said. “Are we physics giants business dwarfs?”

His favorite extracurricular patron in the early 1980s was the Esalen Institute at Big Sur on the California coast, a hub for many varieties of self-actualization, self-enrichment, and self-fulfillment: Rolfing, Gestalt therapy, yoga, meditation. Under the giant trees on cliffs overlooking the Pacific were the original hot tubs, fed by natural sulfur springs. For its many patrons Esalen offered an expensive form of relaxation—a “lube job for the mind,” as Tom Wolfe once put it. Feynman described it as a hotbed of antiscience: “mysticism, expanded consciousness, new types of awareness, ESP, and so forth.” He became a regular visitor. He soaked in the hot tubs, stared gleefully at the nude young women sunbathing, and learned to give massages. He gave some of his standard lectures, adjusted to fit the mental state of the audience. Barefoot, with his thin legs emerging from khaki shorts, he began his “Tiny Machines” talk:

It has to do with the question of how small can you make machinery. Okay? That’s the subject. Because I’ve heard people around, in the baths, saying, “Tiny machines? What’s he talking about?” and I say to them, “You know, very small machines” [pinching an invisible tiny machine between thumb and forefinger] and it doesn’t work. [Pause.]

I am talking about very—tiny—machines. Okay?

And on he would go, to occasional cries of “All right!” from the audience. In the question period, the conversation would invariably turn to antigravity devices, antimatter, and faster-than-light travel—if not in the world of physicists then in the spiritual world. Feynman always answered soberly, explaining that faster-than-light travel was impossible, antimatter was routine, and antigravity devices were unlikely—except, as he said, “that pillow and the floor under your behind will support you effectively for a long time.” For several years he conducted a workshop in “idiosyncratic thinking.” Esalen’s catalog copy promised a route to “peace of mind and enjoyment of life’s contradictions” and added: “You are invited to bring rhythm instruments.”

Late in spring 1984, on his way to pick up one of the first available IBM personal computers in Pasadena, he leapt excitedly out of his car, tripped on the sidewalk, and struck his head on the side of the building. A passerby told him he had a gory enough gash to go to the hospital for stitches. For a few days he felt fuzzy, but he told himself nothing was wrong.

More days went by. It seemed to Gweneth that he was behaving strangely. He awoke in the night and wandered through Michelle’s room. He spent forty-five minutes one day looking for his car, which was parked outside the house. At the house of a model he was drawing, he suddenly undressed and tried to go to sleep; she anxiously told him that he was not at his own home. Finally, after beginning a classroom lecture, he suddenly realized he was speaking disjointed nonsense. He stopped, apologized, and left the room.

A scan of his brain revealed a massive subdural hematoma, slow bleeding inside the skull that was putting strong pressure on the brain tissue. The doctors sent him directly into surgery, where the standard procedure was performed at once: two holes drilled through the cranium to drain the liquid. By the early hours of the next morning Gweneth was relieved to find him sitting up and speaking normally. He had no memory of the lost three weeks. Afterward the specialist who had performed the scan repeated it to rule out a recurrence. He could not resist scrutinizing this remarkably detailed image of Feynman’s brain, the convoluted gray tissue, the wrapped bundles of nerve fiber (“But you can’t see what I am thinking,” Feynman told him), looking for a sign of something different from all the other sixty-five-year-old brains he had scanned. Were the blood vessels larger? The doctor was not sure.

Surely You’re Joking!

Feynman had begun to have autobiographical thoughts around the time of the Nobel Prize. Historians came by to record his recollections, and they treated his notes as artifacts too important to be piled in boxes or strewn about on the shelves in the home office he had made in his basement. Sitting there was Arithmetic for the Practical Man, a relic of his childhood. He still had the adolescent notebook he had sent back and forth to T. A. Welton in the course of reinventing early quantum mechanics. Interviewers set up tape recorders to capture every word of the same stories he had entertained his friends with for decades.

An MIT historian, Charles Weiner, persuaded him to cooperate in what became the most thorough and serious of his interviews. For a while Feynman considered collaborating with Weiner on a biography. They sat in Feynman’s screened back patio while Carl played in a tree house nearby. He not only told his stories but also demonstrated them: “Okay, start your watch,” he told Weiner; then, after they had conversed for eight minutes and forty-two seconds, he interrupted himself and said, “Eight minutes forty-two seconds.” After many hours the conversation sometimes grew intimate. He rummaged through one box and pulled out a photograph of Arline, reclining almost nude, wearing only translucent lingerie. He almost wept. They shut off the tape recorder and remained silent for a time. Feynman kept most of those memories to himself even now.

He began dating his scientific notes as he worked, something he had never done before. Weiner once remarked casually that his new parton notes represented “a record of the day-to-day work,” and Feynman reacted sharply.

“I actually did the work on the paper,” he said.

“Well,” Weiner said, “the work was done in your head, but the record of it is still here.”

“No, it’s not a record, not really. It’s working. You have to work on paper, and this is the paper. Okay?” It was true that he wrote in astonishing volume as he worked—long trains of thought, almost suitable to serve immediately as lecture notes.

He told Weiner that he had never read a scientific biography he had liked. He thought he would be portrayed either as a bloodless intellectual or a bongo-playing clown. He vacillated and finally let the idea drop. Still, he sat for interviews with historians interested in Far Rockaway and Los Alamos and filled out questionnaires for psychologists interested in creativity. (“Is your scientific problem-solving accompanied by any of the following?” He checked visual images, kinesthetic feelings, and emotional feelings and added “(1) acoustic images, (2) talk to self.” Under “major illnesses” he reported: “Too much to list… . Only adverse effects are laziness during recovery period.”)

For several years he had played drums regularly with a young friend, Ralph Leighton, the son of another Caltech physicist. Leighton had begun taping their sessions, and then he began taping the stories Feynman would tell. He urged him on, calling him Chief and begging to hear the same stories again and again. Feynman told them: how he became known in Far Rockaway as the boy who fixed radios by thinking; how he asked a Princeton librarian for the map of the cat; how his father taught him to see through the tricks of circus mind readers; how he outwitted painters, mathematicians, philosophers, and psychiatrists. Or he would just ramble while Leighton listened. “Today I went over to the Huntington Medical Library,” he said one day—his remaining kidney was presenting problems. “But it’s all interesting, how the kidney works, and everything else. You want me to tell you some interesting things? The damn kidney is the craziest thing in the world!”

Gradually a manuscript began to take shape. Leighton transcribed the tapes and presented them to Feynman for editing. Feynman had strong views about the structure of each story; Leighton realized that Feynman had developed a routine of improvisational performance in which he knew the order and pacing of every laugh. They consciously worked on the key themes. Feynman talked about Arline’s having embarrassed him with a box of “Richard darling, I love you! Putzie” pencils:

RICHARD. And the next morning, all right? Next morning, in the mail, there’s this letter, all right, this postcard, which starts out, “What’s the idea of trying to cut the name off the pencils?”

RALPH. [Laughs] Oh, boy! [Laughs.]

RICHARD. “What do you care what other people think?”

RALPH. Oh, this is——Yeah, this is a good theme.


RALPH. This is a good theme, because there’s a theme in here. You know, what other people think …

They knew they had a remarkable central figure, a scientist who prided himself not on his achievements in science—these remained deep in the background—but on his ability to see through fraud and pretense and to master everyday life. He underscored these qualities with an exaggerated humility; he took the tone of a boy calling the grownups Mr. and Mrs. and asking politely dangerous questions. He was Holden Caulfield, a plain old straight shooter trying to figure out why so many other people are phonies.

“Pompous fools—guys who are fools and are covering it all over and impressing people as to how wonderful they are with all this hocus pocus—THAT, I CANNOT STAND!” Feynman said. “An ordinary fool isn’t a faker; an honest fool is all right. But a dishonest fool is terrible!”

His favorite sort of triumph in the world of these stories came in the realm of everyday cleverness—as when he arrived at a North Carolina airport, late for a meeting of relativists, and worked out how to get help from a taxi dispatcher:

“Listen,” I said to the dispatcher. “The main meeting began yesterday, so there were a whole lot of guys going to the meeting who must have come through here yesterday. Let me describe them to you: They would have their heads kind of in the air, and they would be talking to each other, not paying attention to where they were going, saying things to each other like ‘G-mu-nu. G-mu-nu.”’

His face lit up. “Ah, yes,” he said. “You mean Chapel Hill!”

Feynman chose as a title the odd phrase uttered by Mrs. Eisenhart at his first Princeton tea when he asked for both cream and lemon: “Surely you’re joking, Mr. Feynman!” Those words had stayed in his mind for forty years, a reminder of how people used manners and culture to make him feel small, and now he was taking revenge. W. W. Norton and Company bought the manuscript for an advance payment of fifteen hundred dollars, a tiny sum for a trade book. Its staff did not like Feynman’s title at all. They proposed I Have to Understand the World or I Got an Idea (“a nice Brooklyn ring and a little double meaning,” the editor said). But Feynman would not budge. Norton released Surely You’re Joking, Mr. Feynman! in a small first printing early in 1985. It sold out quickly, and within weeks the publisher had a surprising best-seller.

One unhappy reader was Murray Gell-Mann. His attention focused on Feynman’s description of the joy of discovering the “new law” of weak interactions in 1957: “It was the first time, and the only time, in my career that I knew a law of nature that nobody else knew.” Gell-Mann’s rage could be heard through the halls of Lauritsen Laboratory, and he told other physicists that he was going to sue. For late editions of the paperback Feynman added a parenthetical disclaimer: “Of course it wasn’t true, but finding out later that at least Murray Gell-Mann—and also Sudarshan and Marshak—had worked out the same theory didn’t spoil my fun.”

Surely You’re Joking gave offense in another way. Feynman spoke of women as he always had—“a nifty blonde, perfectly proportioned”; “a cornfed, rather fattish-looking woman.” They appeared as objects of flirtation, nude models for his drawings, or “bar girls” to be tricked into sleeping with him. He knew that his diction was not wholly innocent. Sexual politics had caught up with him before, at the 1972 meeting of the American Physical Society in San Francisco, where he accepted the Oersted Medal for contributions to the teaching of physics. His personal relationships were not the issue, although in the male world of Caltech a part of his glamorous reputation with envious students came from his apparent sway over women. He continued to flirt with young women at parties and encouraged Don Juan-style rumors. He frequented one of the first California topless bars, Gianonni’s—he filled its scalloped paper placemats with chains of equations—and amused the local press by testifying in court on its behalf in 1968. There was genuine machismo in the hero-worship of the male graduate students.

He had received a letter the previous fall suggesting that some of his language tended to “reinforce many ‘sexist’ or ‘male-chauvinist’ ideas.” For example, he told an anecdote about a scientist who was “out with his girl friend the night after he realized that nuclear reactions must be going on in the stars.”

She said “Look at how pretty the stars shine!” He said “Yes, and right now I am the only man in the world who knows why they shine.”

The letter writer, E. V. Rothstein, cited another anecdote about a “lady driver” and asked him, please, not to contribute to discrimination against women in science. In replying, Feynman decided not to emphasize his sensitivity:

Dear Rothstein:

Don’t bug me, man!

R. P. Feynman.

The result was a demonstration organized by a Berkeley group at the APS meeting, with women carrying signs and distributing leaflets titled “PR ? TEST” and addressed to “Richard P. (for Pig?) Feynman.”

Despite the women’s movement that emerged in the sixties, science remained forbiddingly male in its rhetoric and its demographics. Barely 2 percent of American graduate degrees in physics went to women. Caltech did not hire its first female faculty member until 1969, and she did not receive tenure until she forced the issue in court in 1976. (Feynman, to the surprise and displeasure of some of his humanities colleagues, had taken her side; he had spent many pleasant hours in her office reading aloud such poems as Theodore Roethke’s “I Knew a Woman”: “I measure time by how a body sways… .”) Like most men in physics, Feynman had known a few women as professional colleagues and believed that he had treated them, individually, as equals. They tended to agree. What more, he wondered, could anyone ask?

The Berkeley protesters had discovered his lady-driver anecdotes but had overlooked other examples of a style of speaking in which, habitually, the scientist is male and nature—her secrets waiting to be penetrated—is female. In his Nobel lecture Feynman had recalled falling in love with his theory: “And, like falling in love with a woman, it is only possible if you do not know much about her, so you cannot see her faults.” And he had concluded:

So what happened to the old theory that I fell in love with as a youth? Well, I would say it’s become an old lady, that has very little attractive left in her and the young today will not have their hearts pound when they look at her anymore. But, we can say the best we can for any old woman, that she has been a good mother and she has given birth to some very good children.

In 1965 a large audience of men and women could listen to these words without taking offense or hearing a politically charged subtext. In 1972 Feynman was able to defuse the protest easily when he took the podium, by declaring: “There is in the world of physics today a tremendous prejudice against women. This is a ridiculous thing and should stop, as there is no sense to it whatsoever. I love the subject of physics and it has always been my desire to try to share the delights of understanding it with any minds that were able to—male or female… .” Many of the demonstrators applauded. In 1985 Feynman once again seemed to some feminists a symbol of male dominance in physics. Real life was complex: one tough-minded Caltech professional would close her door and confide to a stranger that Feynman, even in his sixties, was the sexiest man she had ever known; others, wives of colleagues, resented their husbands for loving him so uncritically. Meanwhile, the status of women in the profession of physics had barely changed.

Despite himself, he was stung by the occasional criticism of Surely You’re Joking. He knew, too, that some of the physicists who had known him longest were disappointed by a self-portrait that made Feynman seem more joker than scientist. His old friends in Hans Bethe’s generation were often pained, or shocked, though they did repeat Feynman’s stories about them with relish, detail for detail, as though from their own memory, Feynman’s voice having transplanted itself into their brains. Others saw through to the essence of what they loved in Feynman. Philip Morrison, writing in Scientific American, said: “Generally Mr. Feynman is not joking; it is we, the setters of ritual performance, of hypocritical standards, pretenders to care and understanding, who are joking instead. This is the book of a powerful mind honest beyond everything else, a specialist in spade-naming.” Feynman nonetheless upbraided people who called the book his autobiography. He wrote in the margin of a science writer’s draft manuscript about modern particle physics: “Not An Autobiography. Not So. Simply A Set Of Anecdotes.” And when he came across a sentence describing him, at Los Alamos, as “a curiously tragic joker,” he scrawled angrily, “What I really was under such circumstances is far deeper than you are likely to understand.”

A Disaster of Technology

In 1958, a hasty four months after Sputnik, Americans entered what was called the space race by sending into orbit the first of a series of Explorer satellites from Cape Canaveral, Florida. Explorer I weighed as much as a fully packed overnight bag. It was hurled skyward on January 31 by a four-stage Jupiter-C rocket—more reliable than the navy’s Vanguard rockets, which had been exploding at liftoff. It sent back radio signals much like Sputnik’s.

Explorer II, bearing a cosmic-ray detector that pushed its weight up to thirty-two pounds, soared skyward five weeks later and disappeared into the clouds. An army team watched under the guidance of Wernher von Braun, resilient veteran of the Nazi rocket program at Peenemünde. They listened to the fading rumble of the rocket and the rising beep of the radio signal transmitted to their squawk box. All seemed well. A half hour after the launch, they held a confident news briefing.

Across the continent, where the Jet Propulsion Laboratory in Pasadena served as the army’s main collaborator in rocket research, a team was struggling with the task of tracking the satellite’s course. They used a room-size IBM 704 digital computer. It was temperamental. They entered the primitively sparse data available for tracking the metal can that the army’s rocket had hurled forward: the frequency of the radio signal, changing Doppler-fashion as the velocity in the line of flight changed; the time of disappearance from the observers at Cape Canaveral; observations from other tracking stations. The JPL team had learned that small variations in the computer’s input caused enormous variations in its output. Albert Hibbs, the laboratory’s young research chief, had complained about this difficulty to his former Caltech thesis adviser: Feynman.

Feynman bet that he could outcompute the computer, if fed the same data at the same rate. So when Explorer II lifted off the pad at 1:28 P.M., he sat in a JPL conference room, surrounded by staff members rapidly sorting the data for the computer. At one point Caltech’s president, Lee DuBridge, entered the room and was startled to see Feynman—who snapped, Go away, I’m busy. After a half hour Feynman rose to say he was finished: according to his calculations the rocket had plunged into the Atlantic Ocean. He left for a weekend in Las Vegas as the trackers kept trying to coax an unambiguous answer from their computer. Tracking stations at Antigua and Inyokern, California, persuaded themselves that they had picked an orbiting satellite out of the background noise, and “moonwatch” teams in Florida spent the night watching the skies. But Feynman was right. The army finally announced at 5 o’clock the next afternoon that Explorer II had failed to reach orbit.

The space shuttle Challenger rose from its launching scaffold into a cloudless sky twenty-eight years later, on January 28, 1986. A half second after liftoff, a puff of dark smoke, invisible to human eyes, spurted from the side of one of the shuttle’s two solid-fuel rockets. The launch had been postponed four times. Inside the cabin, as always, the many-gravity acceleration pressed the crew against their seats: the commander, Francis Scobee; the pilot, Michael Smith; the mission specialists, Ellison Onizuka, Judith Resnick, and Ronald McNair; an engineer from the Hughes Aircraft Company, Gregory Jarvis; and a New England schoolteacher, Christa McAuliffe, who had been chosen as “Teacher in Space,” the winner of a NASA public-relations program meant to encourage the interest of children and also congressmen. The cargo bay—large enough to have carried the 1950s Jupiter-C rocket—held a pair of satellites, a fluid-dynamics experiment, and radiation-monitoring equipment. Ice had built up overnight, and new delays had been ordered while an ice inspection team made sure it had time to melt. Seven seconds after liftoff the shuttle rolled over in its characteristic fashion, so that it appeared to be hanging from the back of its giant disposable fuel tank, and headed east over the Atlantic, its percussive roar audible over hundreds of square miles. The breeze barely bent its column of smoke. At the one-minute mark—halfway through the brief expected lifetime of the solid-fuel rockets—a flickering light appeared where it did not belong, at a joint in the shell of the right-side rocket. The main engines reached full power, and Scobee radioed, “Roger. Go at throttle up.” At seventy-two seconds the two rockets began to pull in different directions. At seventy-three seconds the fuel tank burst open and released liquid hydrogen into the air, where it exploded. The shuttle felt an enormous sudden thrust. A cloud of flame and smoke enveloped it. Fragments emerged seconds later: the left wing, like a triangular sail against the sky; the engines, still firing; and somewhere, intact, a plummeting coffin for six men and a woman. The technologies of television, aided by satellites lofted in earlier shuttle missions, let more people witness the event, again and again, than any other disaster in history.

Machinery out of control. The American space agency had made itself seem a symbol of technical prowess, placing teams of men on the moon and then fostering the illusion that space travel was routine—an illusion built into the very name shuttle. After the nuclear accident at Three Mile Island, Pennsylvania, and the chemical disaster at Bhopal, India, the space-shuttle explosion seemed a final confirmation that technology had broken free of human reins. Did nothing work any more? The dream of technology that held sway over the America of Feynman’s childhood had given way to a sense of technology as not just a villain but an inept villain. Nuclear power plants, once offering the innocent promise of inexhaustible power, had become menacing symbols on the landscape. Automobiles, computers, simple household appliances, or giant industrial machines—all seemed unpredictable, dangerous, untrustworthy. The society of engineers, so hopeful in the America of Feynman’s childhood, had given way to a technocracy, bloated and overconfident, collapsing under the weight of its own byzantine devices. That was one message read in the image replayed hundreds of times that day on millions of television screens—the fragmenting smoke cloud, the twin rockets veering apart like Roman candles.

President Ronald Reagan immediately announced his determination to continue the shuttle program and expressed his support for the space agency. Following government custom, he appointed an investigatory commission that would repeatedly be described as independent—the White House officially declared it “an outside group of experts, distinguished Americans who have no ax to grind”—although in actuality it was composed mostly of insiders and figures chosen for their symbolic value: its chairman, William P. Rogers, who had served as attorney general and secretary of state in Republican, administrations; Major General Donald J. Kutyna, who had headed shuttle operations for the Department of Defense; several NASA consultants and executives of aerospace contractors; Sally Ride, the first American woman in space; Neil Armstrong, the first man on the moon; Chuck Yeager, a famous former test pilot; and, a last-minute choice, Richard Feynman, a professor who brought to the next day’s newspaper accounts the tag “Nobel Prize winner.” Armstrong said on the day of his appointment that he did not understand why an independent commission was necessary. Rogers said even more baldly, “We are not going to conduct this investigation in a manner which would be unfairly critical of NASA, because we think—I certainly think—NASA has done an excellent job, and I think the American people do.”

The White House named Rogers and selected the rest of the commission from a list provided by the space agency’s acting administrator, William R. Graham. As it happened, Graham had attended Caltech thirty years before and had often sat in on Physics X, which he remembered as the best course at Caltech. Later he had attended Feynman’s lectures at Hughes Aircraft. But he did not think of Feynman for the shuttle commission until his wife, who had accompanied him to some of the Hughes lectures, suggested the name. When Graham called, Feynman said, “You’re ruining my life.” Only later did Graham realize what he had meant: You’re using up my very short time. Feynman was now suffering from a second rare form of cancer: Waldenström’s macroglobulinemia, involving the bone marrow. In this cancer, one form of B lymphocyte, a white blood cell, becomes abnormal and produces large amounts of a protein that makes the blood sticky and thick. Clotting becomes a danger, and the blood flows poorly to some parts of the body. Feynman’s past kidney damage was a complication. He seemed gray and wan. There was little his doctors could propose. They could not explain the presence of two such unusual cancers. Feynman himself refused to consider the speculation that the cause might lie forty years in the past, at the atomic bomb project.

He immediately arranged a briefing with his friends at the Jet Propulsion Laboratory in Pasadena. The day after his appointment was announced, he sat in a small room in the central engineering building and met with a succession of engineers. The laboratory, with its advanced image-processing facilities, already had the original negatives of the thousands of photographs taken by the range cameras as the shuttle drove skyward.

The shuttle’s solid rocket boosters were made in sections, assembled one atop another at the launch site. The joints holding the sections together had to be sealed to prevent the escape of hot gasesfrom inside the rocket. Pairs of O-rings-a quarter-inch thickspanned the 37-foot circumference. The pressure of the gas was supposed to wedge them tightly into the joints, creating the seal.

Feynman examined technical drawings and heard from engineers who had worked on the early design studies, on the solid rocket boosters, and on the engines. He learned that the shuttle’s engineers, forming a community across the administrative boundaries that separated NASA’s various departments and subcontractors, shared a knowledge that every launch was at risk. Recurring cracks had appeared in the turbine blades of the shuttle’s engines, at the very edge of engine technology. That first day, February 4, Feynman noted that there were well-known problems with the rubber O-rings that sealed the joints between sections of the tall solid-fuel rockets. These rings represented a remarkable scaling-up of everyday engineering for the high-technology shuttle: they were ordinary rubber rings, thinner than a pencil yet thirty-seven feet long, the circumference of the rocket. They were meant to take the pressure of hot gas and form a seal by squeezing tight into the metal joint. “O-Rings show scorching in Clevis check …” Feynman wrote in a shaky, aging hand. “Once a small hole burn thru generates a large hole very fast! few seconds catastrophic failure.” He flew to Washington that night.

The commission began in a formal and slow-paced style. Rogers opened the first public meeting with a declaration that NASA officials had been cooperative and that the commission would rely largely on the agency’s own investigations. The meeting began with a briefing by NASA’s top spaceflight official, Jesse Moore. Unexpectedly he found himself interrupted by sharp specific questions from Feynman and several other panel members. They focused on the weather, which had been so cold that ice formed on equipment throughout the launching pad. In response, Moore denied that he had had any warning that cold could pose a problem.

That afternoon, however, another agency official, Judson A. Lovingood, from the Marshall Space Flight Center in Alabama, testified that managers for NASA and for Morton Thiokol, the builder of the solid rockets, had held a telephone conference the night before the launch to discuss, as he said, “a concern by Thiokol on low temperatures.” The discussion focused on the O-rings, he said, and Thiokol recommended that the launch proceed. He also mentioned evidence of “blow-by”—soot showing that hot gases had burned through seals that were supposed to contain them. He emphasized, though, that the O-rings were used in pairs and that the secondary O-rings always seemed to hold. “Was that any cause for concern?” asked General Kutyna.

“Oh, yes,” Lovingood replied. “That is an anomaly.”

Newspaper reports the next day, February 7, focused on the issue of cold weather and noted that NASA had been caught off guard by the aggressive questions. When Moore faced the commission again, Feynman immediately began a new series of questions. The chairman twice asked him to put off the questions until later. But the questioning quickly returned to the seals. Another NASA witness testified that the films showed a puff of dark smoke emerging from the side of the right-hand solid rocket six-tenths of a second after ignition. “This is what we would have called an anomaly?” Feynman asked. The witness, Arnold Aldrich, replied carefully, “It is an anomaly unless we find a film where we have seen one just like it.” Pressed by another commissioner, he said:

“Everything that I know about the certification of this seal … is that the certification tests run on that joint show that the seal would be somewhat more stiff, but completely adequate for sealing at all temperatures in the ranges. There was never any intention that the system couldn’t be launched in freezing conditions.”

The chairman commented protectively to Aldrich, “When we ask questions, when we continue to ask questions, we are not really trying to point a finger,” and to Moore, “I thought it was a little unfortunate in the paper this morning that they said that—and I don’t think you really said that—that you had excluded the possibility that the weather had any effect… . If it appears you have excluded that to begin with, particularly because apparently Rockwell did call and gave you a warning which you considered and decided that it was okay to go ahead—suppose that judgment was wrong. Nobody is going to blame anybody. I mean, somebody has to make those decisions.”

But Feynman immediately challenged Moore on the view that O-ring blow-by had been acceptable because the secondary rings had held.

“You said we don’t expect it on the other O-ring,” Feynman said. “On the other hand, you didn’t expect it on the first O-ring… . If the second O-ring gives just a little bit when the first one is giving, that is a very much more serious circumstance, because now the flow has begun.” The air force general, Kutyna, had befriended Feynman when they sat together at the commission’s first news conference. (“Co-pilot to pilot,” he had said softly, choosing this deferential phrase out of worry that Feynman was nervous beside a general in an imposing uniform, “comb your hair,” and Feynman, surprised, growled and asked Kutyna for a comb.) Now Kutyna joined in: “Let me add to your comment… . Once it got a path, then it burns like an acetylene torch.”

Feynman said, “I have a picture of that seal in cross section here, if anybody wants to see it.” No one responded.

For Feynman, for Rogers, for Graham, for the press, and for NASA officials, the weekend of February 8 brought surprises.

Feynman, away from home, thinking of his Los Alamos experience as the prototype for urgent group technical projects, did not want to take Saturday and Sunday off. Through Graham he arranged a series of private briefings on Saturday at NASA’s Washington headquarters. He learned more about the engines, the orbiter, and the seals. He found again that the agency’s engineers understood a long history of difficulties with the O-rings; that two- or three-inch segments of the thirty-seven-foot links had repeatedly been burned and eroded; that a critical issue was the speed with which the rubber had to press into the metal gap—in milliseconds; and that the space agency had found a bureaucratic means of simultaneously understanding and ignoring the problem. He was particularly struck by a summary of a meeting between Thiokol and NASA managers the previous August. Its recommendations seemed incompatible:

✵ The lack of a good secondary seal in the field joint is most critical and ways to reduce joint rotation should be incorporated as soon as possible to reduce criticality… .

✵ Analysis of existing data indicates that it is safe to continue flying… .

Elsewhere at NASA headquarters that day, Graham learned that a storm was about to break: the New York Times had obtained documents showing urgent warnings within NASA about O-ring problems over a period of at least four years. Graham had taken control of the agency only recently, when the administrator, James Beggs, was indicted on fraud charges unrelated to NASA. He immediately telephoned Rogers.

The article appeared Sunday, quoting warnings even more dire than those the engineers had shown Feynman: that a failure of the seals could cause “loss of vehicle, mission, and crew due to metal erosion, burn-through, and probable case bursting resulting in fire and deflagration,” and that

There is little question … that flight safety has been and is being compromised by potential failure of the seals, and it is acknowledged that failure during launch would certainly be catastrophic.

That morning Graham himself took Feynman to the Smithsonian Institution’s National Air and Space Museum, where he sat in a cavernous theater and watched an inspirational giant-screen film about the space shuttle. He was surprised at how emotional he felt.

In the afternoon Kutyna called Feynman at his hotel. As shuttle program manager for the military, Kutyna knew the shuttle more intimately than any other commissioner. He also knew how to run a technical commission, because he had headed the air force’s own investigation into the explosion of a Titan rocket the year before. And he had his own information sources among the engineers and astronauts—one of whom told him over the weekend that Thiokol had known of a potential loss of resiliency when the rubber O-rings were cold. Kutyna wanted to bring this information into the open without jeopardizing his source. He invited Feynman to his house for Sunday dinner. Afterward they went out to his garage—he collected junk cars as a hobby, and at the moment he was working on an old Opel GT. Its carburetor happened to be sitting on his workbench. He told Feynman, you know, those things leak when it’s cold, so do you think cold might have a similar effect on the shuttle O-rings?

Rogers called a closed meeting Monday in reaction to the New York Times revelations. He made clear that he considered them a disruption of his proceedings: “I think it goes without saying that the article in the New York Times and other articles have created an unpleasant, unfortunate situation. There is no point in dwelling on the past.” NASA representatives were asked to respond: “I think that his statement in here where he says that it might be catastrophic I think is overstated,” said one, and Rogers remarked, “Well, that may be.” Lawrence Mulloy, project manager for the solid rockets testified that the rubber in the O-rings was required to operate across an enormous temperature range, from minus 30 to 500 degrees Fahrenheit. He did not know of any test results, however, on the actual resiliency of the O-rings at low temperatures.

Mulloy returned the next morning to give the commissioners a briefing—another in the genre that Kutyna thought of as “telling which was the pointy end of the shuttle because they don’t know that much about it.” He brought more than a dozen charts and diagrams and gave a vivid flavor of the engineering jargon—the tang end up and the clevis end down, the grit blast, the splashdown loads and cavity collapse loads, the Randolph type two zinc chromate asbestos-filled putty laid up in strips—all forbidding to the listening reporters if not to the commissioners themselves. “How are these materials, this putty and the rubber, affected by extremes of temperature? …” one commissioner asked.

Yes, sir, there is a change in the characteristic. As elastomers get colder, the resiliency decreases, and the ability to respond——

Now, the elastomers are what?

That is the Viton O-ring.

The rubber?

Feynman pressed Mulloy on why resiliency was crucial: a soft metal like lead, squeezed into the gap, would not be able to hold a seal amid the vibration and changing pressure. “If this material weren’t resilient for say a second or two,” Feynman said, “that would be enough to be a very dangerous situation?”

He was setting Mulloy up. He had been frustrated by the inconclusive and possibly evasive testimony. He had made an official request for test data, through Graham, and had received documents that were irrelevant, showing how the rubber responded over a period of hours instead of milliseconds. Why couldn’t the agency answer such a simple question? At dinner Monday night his eyes fell on a glass of ice water, and he had an idea that he first thought might be too easy and gauche. Ice water was a stable 32 degrees, almost exactly the temperature on the pad at the time of the launch. Tuesday morning he rose early and hailed a taxicab. He circled official Washington in search of a hardware store and finally managed to buy a small C-clamp and pliers. As the hearing began, he called for ice water, and an aide returned with cups and a pitcher for the entire commission. As a life-size cross section of the joint was passed along for the commissioners to examine, Kutyna saw Feynman take the clamp and pliers from his pocket and pull a piece of the O-ring rubber from the model. He knew what Feynman meant to do. When Feynman reached for the red button on his microphone, Kutyna held him back—the television cameras were focused elsewhere. Rogers called a short break and, in the men’s room, standing next to Neil Armstrong, he was overheard saying, “Feynman is becoming a real pain in the ass.” When the hearing resumed, the moment finally arrived.

CHAIRMAN ROGERS: Dr. Feynman has one or two comments he would like to make. Dr. Feynman.

DR. FEYNMAN: This is a comment for Mr. Mulloy. I took this stuff that I got out of your seal and I put it in ice water, and I discovered that when you put some pressure on it for a while and then undo it it doesn’t stretch back. It stays the same dimension. In other words, for a few seconds at least and more seconds than that, there is no resilience in this particular material when it is at a temperature of 32 degrees.

I believe that has some significance for our problem.

Before Mulloy could speak, Rogers called the next witness, a budget analyst who had written a memorandum that formed the basis of the Times article. The analyst, Richard Cook, had noticed the O-ring problem on a list of “budget threats” month after month, had highlighted it to his superiors, and, when the disaster took place, felt certain that it had been the cause. The chairman, for the first and last time during the shuttle hearings, cross-examined a witness, through the rest of the morning and on into the afternoon, with the cold savagery of a prosecutor:

You didn’t, I assume, make any attempt to weigh budgetary considerations and safety considerations, did you?

Not at all.

You weren’t qualified for that?

No, sir… .

You had no reason to think that people who were weighing those considerations were not qualified to do it? … You didn’t feel that you were in a position or should you make those decisions about what should be done with the space program?

That’s right.

And so that the memo, which has been given a great deal of attention, sort of suggests that you were taking issue with the people who were highly qualified to make those judgments, when in fact you weren’t at all? … You wrote the memo in the heat of the moment, and I assume you were, like everybody else in the country was, terribly disturbed and upset by the accident, and it was in that spirit or at that time when you wrote the memorandum. You didn’t really mean to criticize for public consumption your associates or people around you, did you?

Yet by then it was clear that Cook had described the problems accurately. Feynman’s demonstration dominated the television and newspaper reports that evening and the next morning. Mulloy, under further questioning, made the first clear acknowledgment that cold diminished the effectiveness of the seals and that the space agency had known it, although a straightforward test in the manner of Feynman’s had never been performed. When such tests were finally performed on behalf of the commission, in April, they showed that failure of the cold seals had been virtually inevitable—not a freakish event, but a consequence of the plain physics of materials, as straightforward as Feynman had made it seem with his demonstration. Freeman Dyson said later, “The public saw with their own eyes how science is done, how a great scientist thinks with his hands, how nature gives a clear answer when a scientist asks her a clear question.”

One extraordinary week had passed since Feynman boarded the night flight to Washington. The commission had four months of work remaining, but it had arrived at the physical cause of the disaster.

As the seventies began and the last of the moon landings drew near, NASA had become an agency lacking a clear mission but maintaining a large established bureaucracy and a net of interconnections with the nation’s largest aerospace companies: Lockheed, Grumman, Rockwell International, Martin Marietta, Morton Thiokol, and hundreds of smaller companies. All became contractors for the space-shuttle program, formally known as the Space Transportation System, initially intended as a fleet of reusable and economical cargo carriers that would replace the individual one-use rockets of the past.

Within a decade, the shuttle had become a symbol of technology defeated by its own complexity, and the shuttle program had become a symbol of government mismanagement. Every major component had been repeatedly redesigned and rebuilt; every cost estimate offered to Congress had been exceeded many times over. Unpublicized audits had found deception and spending abuses costing many billions of dollars. The shuttle had achieved a kind of Pyrrhic reusability: the cost of refurbishing it after each flight far exceeded the cost of standard rockets. The shuttle could barely reach a low orbit; high orbits were out of the question. The missions flown were a small fraction of those planned, and—despite NASA’s public claims to the contrary—the scientific and technological products of the shuttle were negligible. The space agency systematically misled Congress and the public about the costs and benefits. As Feynman stated, the agency, as a matter of bureaucratic self-preservation, found it necessary “to exaggerate: to exaggerate how economical the shuttle would be, to exaggerate how often it could fly, to exaggerate how safe it would be, to exaggerate the big scientific facts that would be discovered.” At the time of the Challenger disaster the program was breaking down internally: by the end of the year both a shortage of spare parts and an overloaded crew-training program would have brought the flight schedule to a halt.

Yet the report of the presidential commission, issued on June 6, began by declaring that the accident had interrupted “one of the most productive engineering, scientific, and exploratory programs in history.” It attributed to the public “a determination … to strengthen the Space Shuttle program.”

When Feynman talked about his role later, he fell back on his boy-from-the-country image of himself: “It was a great big world of mystery to me, with tremendous forces… . I hadda watch out.” He claimed no understanding of politics or bureaucracies. These were matters beyond the ken of a technical fellow. Alone among the commissioners, however, Feynman worked to expand the scope of the investigation to include precisely the areas about which he disavowed competence: issues of decision making, communication, and risk assessment within the space agency. Kutyna told him he was the only commissioner free of political entanglements. Despite Rogers’s disapproval he insisted on conducting his own lines of inquiry and traveled alone to interview engineers at the Kennedy Space Center in Florida, the Marshall Space Flight Center in Alabama, the Johnson Space Center in Houston, and the headquarters of several contractors. In between, he made repeated visits to a Washington hospital for blood tests and medication for his worsening kidney, and he talked by telephone with his doctor in California, who complained about the difficulty of practicing medicine at long distance. “I am determined to do the job of finding out what happened—let the chips fall!” he wrote Gweneth proudly. He enjoyed the thrill of the game, and he suspected that he was being carefully managed. “But it won’t work because (1) I do technical information exchange and understanding much faster than they imagine”—he was, after all, a veteran of Los Alamos and the MIT machine shop—“and (2) I already smell certain rats that I will not forget.”

He tried to make use of his naïveté. When Rogers showed him a draft final recommendation, effusive in its praise of the space agency—

The Commission strongly recommends that NASA continue to receive the support of the Administration and the nation. The agency constitutes a national resource and plays a critical role in space exploration and development. It also provides a symbol of national pride and technological leadership. The Commission applauds NASA’s spectacular achievements of the past and anticipates impressive achievements to come… .

—he balked, saying he lacked expertise about such policy matters, and he threatened to withdraw his signature from the report.

His protest was ineffective. The language appeared virtually intact, as the commission’s “concluding thought” rather than a recommendation. Although the commission learned that the decision to launch had been made over the specific objections of engineers who knew of the critical danger from the O-rings, the final report did not attempt to hold senior space-agency officials responsible for the decision. Evidence emerged showing that the history of O-ring problems had been reported in detail to top officials, including the administrator, Beggs, in August 1985, but the commission chose not to question those officials. Feynman’s own findings, substantially harsher than the commission’s, were isolated in an appendix to the final report.

Feynman analyzed the computer system: 250,000 lines of code running on obsolete hardware. He also studied in detail the main engine of the shuttle and found serious defects, including a pattern of cracks in crucial turbine blades, that paralleled the problems with the solid rocket boosters. Overall he estimated that the engines and their parts were operating for less than one-tenth of their expected lifetimes. And he documented a history of ad hoc slippage in the standards used to certify an engine as safe: as cracks were found earlier and earlier in a turbine’s lifetime, the certification rules were repeatedly adjusted to allow engines to continue flying.

His most important contribution to the understanding of the disaster came in the area of risk and probability. He showed that the space agency and its contractors—although the essence of their decision making lay in weighing uncertainties—had ignored statistical science altogether and had used a shockingly vague style of risk assessment. The commission’s official findings could do no better than quote Feynman’s comment during the hearings that the decision making became

a kind of Russian roulette… . [The shuttle] flies [with O-ring erosion] and nothing happens. Then it is suggested, therefore, that the risk is no longer so high for the next flights. We can lower our standards a little bit because we got away with it last time… . You got away with it, but it shouldn’t be done over and over again like that.

Science has tools for such problems. NASA was not using them. A scattering of data points—for the depth of erosion in O-rings, for example—tended to be reduced to simplistic, linear rules of thumb. Yet the physical phenomenon, a hot jet of gas carving channels in rubber, was highly nonlinear, as Feynman noted. The way to assess a scattered range of data was through probability distributions, not single numbers. “It has to be understood as a probabilistic and confusing, complicated situation,” he said. “It is a question of increasing and decreasing probabilities … rather than did it work or didn’t it work.”

On the crucial question of the effect of temperature on O-ring safety, NASA had made an obvious statistical blunder. Seven flights had shown evidence of damage. The most damage had occurred on the coldest flight—at a still-mild 53 degrees Fahrenheit—but no general correlation could be seen between temperature and damage. Serious damage had occurred at 75 degrees, for example.

The error was to ignore the flights on which no damage had occurred, on the basis that they were irrelevant. When these were plotted—seventeen flights at temperatures from 66 to 81 degrees—the effect of temperature suddenly stood out plainly. Damage was strongly associated with cold. It was as if, to weigh the proposition that California cities tend to be in the westernmost United States, someone made a map of California—omitting the non-California cities that would make the tendency apparent. A team of statisticians formed by the National Research Council to follow up the commission report analyzed the same data and estimated a “gambling probability” of 14 percent for a catastrophic O-ring failure at a temperature of 31 degrees.

Feynman discovered that some engineers had a relatively realistic view of the probabilities involved—guessing that a disaster might occur on one flight in two hundred, for example. Yet managers had adopted fantastic estimates on the order of one in a hundred thousand. They were fooling themselves, he said. They cobbled together such numbers by multiplying absurd guesses—that the chance of a turbine pipe bursting was one in ten million, for example.

He concluded his personal report by saying, “For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.” He joined his fellow commissioners for a ceremony at the White House Rose Garden. Then he returned home, as he now knew, to die.