Genius (61 page)

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
r
II. 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
r
II 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
r
II 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
r
II 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.