Richard Feynman

by John Gribbin

  The war in Europe had begun almost exactly at the time Feynman was joining Princeton, in the autumn of 1939. Over the following months, the United States became increasingly involved in the war effort as a ‘neutral’ supporter of the British cause, and it seemed increasingly likely that at some stage the country would formally join in the fight against Hitler. Few of Feynman’s peers had any doubts that this would be the right thing to do; many eminent Jewish scientists (including Einstein) were now based in America precisely because they had had to flee from Hitler’s Germany, and the war could be understood in black and white terms (and was, indeed, being presented that way in government propaganda), as ‘good guys against bad guys’.

  Like many of his contemporaries, Feynman increasingly felt that he ought to do something to help the war effort. When he had been at MIT, he had repeatedly tried to get a summer job at the Bell Laboratories, failing (it seems likely with hindsight) because of an unspoken objection to his Jewish background. In the spring of 1941, at the fourth or fifth time of asking, he was accepted, and felt very happy. But then a General visited Princeton, to give a talk about the importance of physics in the modern army, exhorting the young physicists to take up war work. Carried away by the patriotic fervour, Feynman gave up the opportunity to work at Bell Labs (even though they offered to give him war-related work), and spent the summer instead at the Frankfort Arsenal, in Philadelphia, working on a mechanical detector (a kind of primitive computer) to be used by artillery specialists to predict where an aeroplane would be by the time the shells fired from the guns reached its altitude. He was so successful that the army offered him a long-term job at the end of the summer, as head of his own design team. But in September he went back to Princeton to finish his PhD. He hadn’t enjoyed the army’s bureaucratic way of doing things, and felt that he should have gone to Bell Labs after all. But the experience of military research in the summer of 1941 was soon to stand him in good stead.

  Finishing the PhD was, of course, simply a formality. Feynman had completed the preliminary requirement, the qualifying examination, a year earlier, in the autumn of 1940, having spent most of the summer at MIT (where he could work without disturbance, in the library) studying in preparation for the event. He had indeed carried out original research work, with John Wheeler, and all that was left was to write up his thesis satisfactorily (even Feynman realized that he would be able to defend it adequately). But the outside world intervened. The Japanese attack on Pearl Harbor brought the United States into the war, against both Japan and Germany, on 8 December 1941.

  One morning in December, one of the Princeton physicists, Robert Wilson, came into Feynman’s office. He told Dick that he had a secret to divulge, something that Wilson wasn’t supposed to tell Dick, but which he would anyway, because he knew that once Dick heard the story he would join Wilson’s Top Secret project. He explained about the possibility of building an atomic bomb, the fear that Germany might already be working on such a project, and the need to find a technique for separating the radioactive uranium-235 that would be needed for such a bomb from the more common, stable variety, uranium-238. Wilson’s project involved a way of carrying out this separation (not the technique that was actually used, in the end, to make the first bombs), and he wanted Feynman to join the team.21

  Feynman’s first reaction was to say no. He had had enough of military bureaucracy. He would keep the secret, but he had to finish his thesis before he could think of doing anything else. Wilson got up and quietly left the office, telling Dick that if he changed his mind, he would be welcome to attend a meeting in Wilson’s office at three o’clock that afternoon. Feynman tried to get back to work on his thesis, but couldn’t. He thought about the possibility of Hitler obtaining a nuclear bomb, and the implications. He remembered the stories he had heard from the refugees from Hitler’s Germany. At three o’clock, he was at the meeting in Wilson’s office. By four o’clock, he had his own desk in another office and was at work, the thesis temporarily abandoned in the drawer of the old desk. It was the right decision. All science in the United States stopped during the war, except for what became the Manhattan Project – ‘and that’, said Feynman in Surely You’re Joking, ‘was not much science; it was mostly engineering’.

  Feynman worked for a few months on the uranium separation project, but it wasn’t moving as fast as had been hoped, so in the spring of 1942, urged on by Wheeler (who was by now working with Enrico Fermi in Chicago on the design and construction of the world’s first artificial nuclear reactor, and warned Dick that this might be his last chance to finish the PhD before becoming totally embroiled in war work), he took a few weeks’ leave to finish his thesis. Then, after submitting the thesis, he went back to work with Wilson’s team. The thesis examiners, John Wheeler and Eugene Wigner, described it as ‘exceptionally original’, and the official report of his oral examination, held on 3 June 1942, rated his performance as ‘excellent’.22 Feynman formally received his PhD degree at the regular Princeton commencement ceremony in June 1942, attended by his proud parents. But one important person was not present. Arline was ill in hospital with what had recently (but belatedly) been diagnosed as tuberculosis. According to Wheeler, her tragic illness may have been exacerbated by her overtaxed lifestyle, burning the candle at both ends, being a full-time art student in New York by day, teaching piano in the evenings to pay for her course, and visiting Richard at Princeton whenever possible for weekend dances.23 In spite of the serious nature of her illness, the couple married before the end of the month, fulfilling their longstanding promise to each other.

  The relationship between Richard and Arline had initially continued while he was at Princeton in very much the same way as it had gone on while he was at MIT. They spent a lot of time together during the vacations, and she visited him increasingly often at Princeton. It was Arline who, around this time, would try to shake Richard out of any gesture he made towards conformity by reminding him of what he had said to her many times before: ‘What do you care what other people think?’ The slogan became the title of his second bestselling book in the 1980s. But just when the future looked assured for the couple, Arline developed a lump in her neck. It wasn’t painful, but she began to feel increasingly tired – Joan Feynman recalls24 an occasion when the Feynman family went to stay in Atlantic City for a holiday, and Dick joined them for the weekend. Everyone was swimming in the pool, having a great time, but Arline had to get out and lie down because of her tiredness.

  After a while, the lump changed slightly, Arline developed a fever and was taken into hospital. The illness was initially misdiagnosed, first as typhoid, then as Hodgkin’s disease. Meanwhile Feynman, reading up the symptoms in the medical library at Princeton, decided that they matched those of tuberculosis of the lymphatic glands. But the textbook said ‘this is very easy to diagnose’, so he decided that that couldn’t be the problem, or the doctors would have found it.25 Either way, Hodgkin’s disease or TB, the disease was, in those days, almost certainly fatal. Feynman wanted to tell Arline the truth, but was prevailed upon by her family to join in a ‘white lie’ that it was only glandular fever, and that she would soon recover.

  For a time, Arline did get slightly better, and returned home, where she guessed that the illness was much more serious when she heard her mother crying. To his immense relief, Richard was able to tell her the truth (as the doctors saw it at the time), and the couple began to re-plan their future in the light of this new development.

  By now, Richard was nearing his final year at Princeton, and had been awarded a scholarship, one of the stipulations of which was that it could not be held by a married student. His first reaction to the news of Arline’s death sentence – she had been given a maximum of two years to live was that he wanted to marry her at once, and look after her for her final years. Incredibly, when Feynman asked permission for the ‘no marriage’ rule to be waived in this very special case, it was refused. He would have to choose between the scholarship and marriage, and
without the scholarship he couldn’t afford to live while completing his PhD. Feynman seriously considered giving up the thesis and seeking a job with Bell Labs, or somewhere similar. But then, at last, came the final, correct diagnosis of Arline’s condition. It was indeed tuberculosis of the lymphatic glands.

  The situation by then was so desperate that, in spite of Feynman’s anger at his own failure to press the possibility of this diagnosis on the doctors (although it is hard to see how they would have taken much notice of him), the couple regarded this diagnosis as good news. After all, according to the doctors it might mean that Arline would live for another five years. So the immediate pressure to marry was eased, and Richard did keep the scholarship, finish his PhD and get started on the road that would lead him to Los Alamos to work on the Manhattan Project.

  Feynman came under enormous pressure from his family and friends not to go through with the marriage. Chief among the opposition, Melville still thought that marriage, even to a healthy bride, would damage Richard’s career prospects, while Lucille was more concerned that he would catch TB and die. But there was never any doubt in Richard’s own mind that he was doing the right thing, even though he and Arline understood that they could only ever have a limited physical relationship, and could not even kiss for fear of contagion. The decision to go ahead with the marriage as soon as he had received his PhD led to a rift between Richard and his parents which was never really healed, but he never regretted the decision.

  By the time Dick had been awarded his PhD, Arline was permanently hospitalized, staying at the state hospital on Long Island. He arranged for her to move to a charitable hospital called the Deborah Hospital, at Browns Mills (near Fort Dix), in New Jersey, close to Princeton. He borrowed a stationwagon from a friend at Princeton, and fixed it up, as he described in What Do You Care, ‘like a little ambulance’, with a mattress and sheets in the back for Arline to rest on. On 29 June 1942, the couple had a romantic ride on the Staten Island Ferry, and got married in the borough of Richmond (sealing the ceremony with a chaste kiss on the cheek); then the groom delivered his bride to the Deborah Hospital, and left her there, where he could visit her every weekend.

  For a while, the newly married, newly qualified Dr Feynman stayed on at Princeton, working on the fringes of what was now called the Manhattan Project. Arline, an indomitable character, kept her spirits up in hospital by writing daily letters to Dick, initiating crazy projects (more of these in Chapter 5), and planning for what she knew was a mythical future of normal married life. Once, she sent Dick a box of pencils, each one emblazoned in gold with the message ‘RICHARD DARLING, I LOVE YOU! PUTSY’. He was pleased, but embarrassed. The message was nice, and (as Arline had known) he needed pencils. Such stuff was in short supply, and too valuable to waste. But he didn’t want one of the professors noticing the legend. So he got a razor blade and neatly cut the message off of the pencil he was using. But Arline was ahead of him.

  Next morning, he received a letter from her, beginning ‘WHAT’S THE IDEA OF TRYING TO CUT THE NAME OFF THE PENCILS?’, and ending ‘WHAT DO YOU CARE WHAT OTHER PEOPLE THINK?’ He left the rest of the pencils intact, ignoring the gentle ribbing that resulted when colleagues picked them up. It was a message that he took to heart, carrying it with him to Los Alamos and beyond, right up to his involvement with the Challenger inquiry. But before we go into all that, it is time to take stock of the scientific work with which Feynman made his initial reputation, as an undergraduate at MIT and then as a research student at Princeton.

  Notes

  1. Mehra.

  2. Mehra.

  3. Quoted by James Gleick in Genius (see Bibliography).

  4. From an unpublished memoir by Welton, written in 1983; quoted by Mehra.

  5. Mehra.

  6. Mehra.

  7. Surely You’re Joking.

  8. Mehra.

  9. Most of the Good Stuff.

  10. See letters between Smyth and Morse, and Smyth and Slater, Princeton archive (Seeley G. Mudd Manuscript Library).

  11. Philip Morse, In at the Beginnings, MIT Press (1977).

  12. Joan Feynman, correspondence with JG, January/February 1996.

  13. Wheeler, in Most of the Good Stuff.

  14. Mehra.

  15. This was, in fact, a characteristic he shared with Einstein; see Einstein: A Life in Science.

  16. Ralph Leighton, comment to JG, December 1995.

  17. What Do You Care.

  18. Leighton, comment to JG, December 1995.

  19. Wheeler, in Most of the Good Stuff.

  20. Princeton archive.

  21. Mehra.

  22. Report in the Princeton archive.

  23. See Wheeler’s contribution to Most of the Good Stuff.

  24. See No Ordinary Genius.

  25. What Do You Care.

  * For those who are not familiar with the American educational system, a freshman is a first-year undergraduate, a sophomore is a second-year student, a junior is a third-year student on a four-year course, and a senior is a final-year undergraduate.

  4 Early works

  Although Feynman failed to get much intellectual stimulation from being forced to attend classes in English and philosophy during his time as an undergraduate at MIT, he had ample opportunity to stretch his mind by attending any classes that did interest him, even if they did not count officially towards his degree. One of the classes he attended in his senior year was taught by Manuel Vallarta, who had an interest in cosmic rays – high-energy particles that reach the Earth from space. These ‘rays’ come equally from all directions – they are isotropic – but the stars of our Galaxy, the Milky Way, are distributed far from uniformly across the sky. The obvious inference is that cosmic rays do not come from within our Milky Way Galaxy, but from the Universe at large, beyond the Milky Way. But even if cosmic rays did come in to the Galaxy uniformly from all directions, surely, Vallarta thought, they ought to be scattered by the stars of the Milky Way, and end up with an uneven pattern on the sky. He discussed the puzzle with Feynman, and suggested that the bright undergraduate might like to work on the puzzle of the isotropy of cosmic rays.

  Feynman was able to solve the puzzle in a fairly straightforward manner, proving that if cosmic rays from the Universe at large do indeed enter our Galaxy isotropically, then they will still be seen coming from all directions when they reach the Earth. The influence of the stars of the Milky Way is far too small to disturb the pattern. One interesting feature of Feynman’s proof is that it involved dealing mathematically not just with cosmic ray particles coming into the Galaxy from outside, but with a kind of hypothetical mirror image set of particles moving out from the Galaxy into deeper space. The kind of scattering Vallarta was worried about mainly involves the magnetic fields of stars, which interact with electrically charged particles. So the probability of an electron (with negative charge) coming into the Galaxy along a particular path is the same as the probability of a positron (with positive charge) going out of the Galaxy along the same path.

  In fact, some cosmic rays are now known to originate within our Galaxy, but that does not affect the validity of Feynman’s argument – those cosmic rays which do originate from outside the Milky Way (essentially the ones with most energy, which is why they were the first to be studied) behave just as he calculated on their way to Earth. Vallarta was sufficiently impressed by Feynman’s proof that he offered to tidy it up and submit it to the Physical Review for publication, under their joint names. He explained to Feynman that although he (Vallarta) had made only a small contribution to the paper, his name should appear first on it, because he was the more senior scientist. It was Feynman’s first experience of this kind of jockeying for academic credit, but he was hardly in a position to object, and the paper appeared in the Physical Review on 1 March 1939, with the authorship ‘Vallarta and Feynman’.

  But Feynman would have the last laugh. In 1946, Werner Heisenberg published a book on cosmic rays in which he discussed just about ev
ery worthwhile paper ever published on the topic. The Vallarta and Feynman paper didn’t quite fit in anywhere, but right at the end of the book Heisenberg discussed the possibility of the influence of stellar magnetic fields in changing the direction of cosmic rays and, in his very last sentence, concluded that ‘such an effect is not expected according to Vallarta and Feynman’. The next time Feynman met up with Vallarta, he gleefully asked if he had seen Heisenberg’s book. Vallarta already knew what was coming. ‘Yes’, he said. ‘You’re the last word in cosmic rays.’1

  Feynman had time to do research – albeit in a modest way – in his senior year because by then he was only serving out time as far as the requirements for his degree were concerned. The rules said you had to serve four years as an undergraduate before receiving the Bachelor’s degree. Feynman had long since learned everything required of a physics student, and more, but he hadn’t completed the statutory four years. In fact, unknown to Feynman at the time, Philip Morse had actually suggested to the authorities at MIT that Feynman should be allowed to graduate a year early, after three years instead of four; but the proposal had been turned down. All that was left was for Feynman to write his senior thesis – no small task at the end of the 1930s, when students were expected to do original work on a specific problem suggested to them by a supervisor. The supervisor was supposed to be aware of the broad sweep of the development of science, and able to pinpoint a tiny area, equivalent to adding one brick to the tower of knowledge, where the undergraduate could make a genuine contribution. Feynman’s senior thesis started out like that, but ended up as a much more far-reaching piece of work.