Dirac’s modesty was genuine, but he was not above a little vanity. The Danish sculptor Harald Isenstein, a specialist at portraying leading physicists, made two busts of Dirac, and both are good likenesses, if lacking in character: the first in 1939, which Dirac displayed in his home, the next thirty-two years later.46 He offered the first Isenstein bust to St John’s College, who accepted it and displayed it in their library, where it stands today. The college also wanted a painting of Dirac in oils to be displayed in their Hall, and Dirac went out of his way to oblige.47 In the early summer of 1978, he sat several times for Michael Noakes, portrait painter of the British royal family and, the year before, of Frank Sinatra.48 In the first session, Noakes tried to help Dirac relax by drawing him into conversation:
NOAKES: Can you put into layman’s terms what you’re working on, Professor?
DIRAC: Yes. Creation.
NOAKES: Wow! Tell me more.
DIRAC: Creation was one vast bang. Talk of a steady state is nonsense.
NOAKES: But if nothing existed beforehand what was there to bang?
DIRAC: That is not a meaningful question.
Dirac would say no more. Though unsettled by Dirac’s reticence and apparent lack of interest, Noakes captured his abstracted gaze to infinity, Dirac looking as innocent as a five-year-old, as detached as an oracle.49 A comparison between this portrait and the first to be painted – by his friend Yakov Frenkel in 1933, shortly after they heard of Ehrenfest’s suicide – shows how much Dirac’s confidence had drained away in the ensuing forty-five years. His personality is perhaps best caught in the drawing made in 1963 by Robert Tollast, whose portrait expertly catches Dirac’s childlike innocence. Less accomplished, but nevertheless competent, is the drawing of Dirac made two years later by Feynman, whose portrait shows signs of reverence (‘I’m no Dirac,’ Feynman often said).50 Dirac kept his drawing in his filing cabinet.
Twenty years after Dirac declined a knighthood, he accepted the most prestigious honour of all, membership of the Order of Merit, which did not oblige him to call himself anything other than ‘Mr Dirac’.51 The order is limited to twenty-four members of the British Commonwealth judged by the sovereign to have given exceptional service (previous members had included Florence Nightingale, Winston Churchill and William Walton). Manci deplored that her husband was the last of his generation of Cambridge scientists to be honoured – J. J. Thomson, Eddington, Rutherford, Cockcroft and Blackett had been admitted long before.52
In June 1973, the Diracs returned to the UK so that he could collect his award. A chauffeur drove them in a Rolls Royce to Buckingham Palace, where he received the award in private from the Queen for a few minutes, while Manci waited in an ante-room. A few weeks later, he shared with Esther and Myer Salaman his discussions with the Queen about the challenges faced by a female scientist who is also the mother of young children:
I said it was difficult for a woman who had to choose between her career and her family and there could not be real equality between the sexes. The Queen said she did not press for equality of the sexes.53
On his return to the USA, Tallahassee colleagues quizzed Dirac about his impression of the Queen, but he would say very little. His description of her consisted of two words: ‘Very small.’54
That summer, Dirac visited CERN in Geneva to see its newest particle accelerator, capable of increasing the energy of protons to some fifty thousand times the energy reached by Cockcroft and Walton’s device. During his visit, he walked to the rue Winkelried, a side street near the lake and close to the main railway station, to see the apartment owned until the mid-1920s by his paternal grandmother, where he and his family stayed in 1905. As he strolled around the nearby statue of Rousseau, Dirac may have thought of the time he spent running around in the lakeside park with Felix, watched by his father and mother, baby Betty in her arms. Dirac had not visited Switzerland since then, despite many invitations. The pain of the country’s association with his father had been so deep that Dirac had not been able to bring himself to visit it until he was seventy years old.
In 1979, the centenary of Einstein’s birth, Dirac was feeling weak and listless. But he was determined to speak at as many of the celebratory meetings as he could, so that he could ‘make clear what a great scientist Einstein was’, as Halpern recalled.55 During that year, Dirac achieved one of his ambitions – of flying across the Atlantic on Concorde, the first supersonic passenger aircraft. The aircraft, developed by an Anglo-French collaboration in the 1960s, was noisy, a prodigious guzzler of fuel and hopelessly uneconomic, but it symbolised the best and most exciting in contemporary engineering. It was also the apogee of the aviation industry in Dirac’s native city: the Bristol Aeroplane Company had led the first British design team to work on the aircraft and build the first British prototype in Filton, a few miles from Julius Road.56
Somehow, Manci persuaded UNESCO to fund transatlantic flights on the aircraft for Dirac and herself as a condition of his attending the organisation’s Einstein celebration in Paris, as guest of honour.57 He and Manci took the flight on 5 May 1979, cruising at almost 60,000 feet – the nearest he would ever get to outer space. During the flight, he probably read on the front page of the New York Times the news from Britain that Margaret Thatcher had just become Prime Minister.58 He may have wondered whether his mother’s fears about the notion of a woman prime minister would be realised, whether Mrs Thatcher would, in Flo’s words, ‘vacillate in her feminine way’ so that ‘her supporters would fall off right and left’.59
By spring 1982, when Dirac and Kapitza were tired of travel, three opportunities to meet that summer arose, and they seized them.60 Accompanied by their wives, they met first at the Lindau meeting at the end of June. Kapitza had been eligible to attend the meeting only since he received the Nobel Prize for physics in 1978, after Dirac had lobbied for him for almost forty years. During that time, Dirac had seen the honour awarded to almost all of Rutherford’s most able ‘boys’ – Blackett, Chadwick, Cockcroft and Walton – and virtually all the pioneers of quantum mechanics from the 1920s and 1930s had received the prize, including Born, Fermi, Landau, Pauli, Tamm and Van Vleck, but not Jordan, whose Nazi past probably cost him the honour.
At the Lindau meeting, Dirac mounted one of his last attacks on renormalisation in front of an audience of some two hundred students and Nobel laureates.61 Looking as fragile as a cut-glass figurine, Dirac stood at the rostrum giving a speech almost identical to ones he had been giving for almost fifty years; he had no praise for the Standard Model or any other successes of particle physics. A microphone amplified his trembling voice, each letter ‘s’ accompanied by a whistle from his ill-fitting dentures. Current theories were ‘just a set of working rules’, he said; physicists should go back to basics and find a Hamiltonian description of nature free of infinities. ‘Some day’, he said with a gentle and weary defiance, ‘people will find the correct Hamiltonian.’ But he was preaching a lost cause: physicists no longer based their descriptions of fundamental particles on Hamiltonians, as other methods were much more convenient. But the audience listened respectfully to Dirac’s twenty-five-minute speech, partly, perhaps, in anticipated sadness that his lone voice would soon be silent. Here was someone, like Einstein, who was unafraid of bucking contemporary trends and taking the consequences, to be his own man.
The Diracs and Kapitzas met again a few days later in Göttingen. Kapitza had pleasant recollections of the town, as did Dirac – it was, in his opinion, the birthplace of quantum mechanics, where he had first become acquainted with Born and his group, where he became friends with Oppenheimer and probably where he first saw a Nazi in uniform. The Diracs stayed in Gebhard’s Hotel overlooking Göttingen railway station, where Dirac had first arrived in the town from Copenhagen fifty-five years before.62 Then, his journey from the station to his room in the Carios’ home was a luggage-laden walk; now, he and Manci were met by a welcoming party that whisked them in a taxi to the town’s most luxurious accommodatio
n.
There are photographs of Kapitza and Dirac sitting at a table in the garden of the hotel, looking exhausted and a little dispirited. Physics, once one of their main topics of conversation, was now much less important than international affairs, the preoccupation of Kapitza. He will almost certainly have spoken with Dirac about the recently ended Falklands War between Argentina, led by General Galtieri, and the United Kingdom, led by Mrs Thatcher, over the disputed island territory in the South Atlantic. Dirac was in two minds about Thatcher: he feared the impact of her radicalism on British education and science but sympathised with her determination to protect the Falkland Islanders’ wish to remain British. He thought, however, that the dispute should have been resolved through negotiation: at the beginning of the war, it had seemed absurd to him that the number of people likely to die would exceed the number whose British citizenship would be protected.63 In politics, if not in physics, Dirac was now a pragmatist.
The Falklands War was a trivial matter compared with nuclear proliferation, a subject Dirac and Kapitza talked about at length when they met again a few weeks later, at the Erice summer school in Sicily, organised by the physicist Antonino Zichichi. Dirac took risks in the subject matter he addressed there: during the previous summer, he had given a presentation on ‘The Futility of War’, an uncomplicated statement of an argument that few would oppose.64 In the summer of 1982, he collaborated with Kapitza and Zichichi to write the one-page ‘Erice Statement’, which urged governments to be less secretive in defence matters (one of Bohr’s favourite themes), to prevent the spread of nuclear weapons and to help non-nuclear powers feel more secure.65 The well-intended phrasing of the document, later signed by ten thousand scientists, was so bland that its first signatories at the Erice meeting included not only opponents of nuclear weapons but also the right-wing Eugene Wigner and the obdurately pro-nuclear Edward Teller, who had done more than almost any other American to fuel the arms race.
On the last stages of the Diracs’ 1982 European tour, they visited Betty in Amsterdam and Gabriel in Aarhus, before travelling to Cambridge. Dirac returned to St John’s College, which, as he was to tell the Master soon afterwards, ‘has been the central point of my life and a home to me’.66 That summer, the talk of the Combination Room was the imminent arrival of the college’s first women undergraduates: another all-male bastion of Cambridge was about to fall. Earlier, the theoretical physicist Peter Goddard asked Dirac whether he thought women students should be admitted to the college, and, after a long pause, Dirac replied, ‘Yes, provided we don’t admit fewer men.’67
Before he left St John’s, Dirac left his gown at the Porters’ Lodge, where he had first registered as a student almost sixty-nine years before. He wrote a label: ‘Professor Dirac’s Gown. Please take it to the Master and ask him to keep it until the next time I come to Cambridge.’ But he would not see the town again.
Notes - Chapter twenty-eight
1 Press release from Dorothy Turner Holcomb, ‘Barbara Walters… I needed you!’, 9 March 1971, Dirac Papers, 2/6/11 (FSU).
2 Walters (1970: 173).
3 Notes on ‘The Evolution of our Understanding of Nature’, 8 March 1971, in Dirac Papers, 2/28/21 (FSU).
4 Between 1969 and 1983, Dirac gave about a hundred and forty talks, an average of ten talks a year. He gave about eighty-eight talks in the USA, and fifty-two talks overseas, mainly in Europe but occasionally further afield, notably in Australia and New Zealand in 1975. See Dirac Papers, 2/52/8 (FSU).
5 Interview with Kurt Hofer, 21 February 2004.
6 Interview with Pam Houmère, 25 February 2003.
7 E-mail from Hans Plendl, 5 March 2008, and another from Bill Moulton, 5 March 2008.
8 Interview with Kurt Hofer, 21 February 2004. Hofer recalls that Dirac would melt when he realised that the person he had dismissed was a friend.
9 Interview with Hofer. Leopold Halpern independently confirmed this description of Dirac’s telephone manner.
10 Pais (1997: 211). Many of Dirac’s colleagues at Florida State University, including Steve Edwards (interview, 27 February 2004) and Michael Kasha (interview, 18 February 2003), attest to the enjoyment he took in telling this joke.
11 M. Dirac (2003: 39).
12 Interview with Barbara Dirac-Svejstrup, 5 May 2003.
13 Letter from Manci to Dirac, undated, August 1972, Dirac Papers, 2/7/2 (FSU).
14 Letter from Manci to Dirac, 18 August 1972, Dirac Papers, 2/7/2 (FSU).
15 Interview with Ken van Assenderp, 25 February 2003.
16 Interview with Helaine and Yorrick Blumenfeld, 10 January 2004. Helaine Blumenfeld recalls: ‘When I was pregnant with my second son, Manci called me all the time to check on things.’ Shortly before one of Mrs Blumenfeld’s appointments up at Addenbrooke’s Hospital, Manci advised her, ‘Well, you know they have a lot of black doctors there. Don’t let them touch you, they’re all dirty.’ Monica Dirac recalls that her mother was ‘the most anti-Semitic person I’ve ever met’, quite surprising as Manci herself was Jewish. Monica learned of her Jewish ancestry when she was twenty-one years old. Interviews with Monica Dirac, 7 February 2003 and 3 May 2006.
17 Interview with Yorrick and Helaine Blumenfeld, 10 January 2004.
18 Interview with Lily Harish-Chandra, 12 July 2007.
19 Quoted in Chandrasekhar (1987: 65).
20 The clearest account of Dirac’s research agenda during his later years is in the summary he wrote for Joe Lannutti in November 1974, Dirac Papers, 2/7/9 (FSU).
21 Halpern (2003: 25). Interview with Leopold Halpern, 18 February 2003.
22 Halpern (2003: 24–5).
23 Leopold Halpern took me on this same trip on Sunday 26 February 2006. During this trip, and in earlier interviews, he described their trips down the river and their reception at home by Manci. In a separate interview, on 27 February 2004, Steve Edwards described the infamous incident in which Dirac dumped Kursunoglu in the Wakulla River
24 Weinberg (2002).
25 The special type of gauge theory, was first written down by Yang and his collaborator Robert Mills in 1954. Yang has described the theory as ‘a rather straightforward generalization of Maxwell’s equation’ (quoted in Woolf 1980: 502).
26 Crease and Mann (1986: Chapter 16).
27 In the late 1970s Dirac erroneously analysed the opacity of the universe and his error involved a misunderstanding of the Kapitza–Dirac effect (e-mail from Martin Rees, 27 November 2006). Another error is noted in Dalitz and Peierls (1986: 175).
28 Interview with Leopold Halpern, 18 February 2002. Halpern recalled that Dirac took the discovery seriously and wanted to understand it. ‘How can you explain this portrait of Jesus? How can this happen?’ Dirac said several times. (The shroud was later proved to be a fake.)
29 There is no record of Dirac’s taking any interest at all in the modern theory of renormalisation. He did, however, acknowledge the brilliance of physicists who worked on the theory, including Abdus Salam, Gerhard ’t Hooft and Edward Witten, whom he nominated for awards. Evidence of these nominations is in the Tallahassee archive.
30 Interview with Rechenberg, 3 June 2003.
31 Dirac (1977).
32 Brown and Hoddeson (1983: 266–8).
33 Interview with Lederman, 18 June 2002.
34 Interview with Lederman, 18 June 2002. See Farmelo (2002b: 48). Einstein came close to predicting the existence of the positron in his 1925 paper ‘Electron and General Relativity’, see Fölsing (1997: 563–5).
35 Many female acquaintances attest to Dirac’s behaviour in this respect, notably Lily Harish-Chandra, Rae Roeder, Helaine Blumenfeld and Colleen Taylor Sen.
36 Kursunoglu and Wigner (1987: 26). See Mill (1869), especially Chapter 3, ‘Of Individuality, as One of the Elements of Well-Being’.
37 Interview with Kurt Hofer, 21 February 2004.
38 E-mail from Kurt Hofer, 6 March 2004.
39 Letter from Manci to Rudolf Peierls, 23 December 1985, Peierls archiv
e, additional papers, D23 (BOD).
40 Interview with Christine Teszler, 22 January 2004, and an e-mail, 27 March 2004.
41 This incident occurred in 1978 as Dirac and Hofer passed the Mormon church on Stadium Drive, Tallahassee. Interview with Hofer, 21 February 2004.
42 Talk on ‘Fundamental Problems of Physics’, 29 June 1971 (audio recording from LINDAU). See Dirac Papers, 2/28/23 (FSU).
43 In the talk, Dirac suggested a probability for the formation of life that he considered would make it overwhelmingly unlikely without the presence of a God: a chance of one in 10100 (a power of ten also known as a googol).
44 E-mail from Kurt Hofer, 28 August 2006.
45 Halpern (1988: 466 n.). See also Dirac’s notes on his lecture ‘A Scientist’s Attitude to Religion’, c. 1975, Dirac Papers, 2/32/11A (FSU).
46 Isenstein contacted Dirac after meeting him at Bohr’s home: letter from Isenstein to Dirac, 29 June 1939, Dirac Papers, 2/3/9 (FSU). Isenstein renewed contact with Dirac in 1969, see letter from Isenstein to Dirac, 29 June 1969, Dirac Papers, 2/6/7 (FSU).
47 For correspondence concerning the bust, see the correspondence in the summer of 1971, Dirac Papers, 2/6/11 (FSU).
48 I thank Michael Noakes for his comments on Dirac’s sitting for this portrait (interview, 3 July 2006). Noakes points out that Frank Sinatra did not sit for his portrait, though he much liked the result, which he hung on a wall of his study.
49 Dirac liked the picture, though he grumbled slightly: ‘It makes me look a bit old.’ Dirac was sensitive about the mark on the left side of his nose, the remains of a precancerous cyst, removed in the summer of 1977. For this reason, Noakes’s portrait of Dirac shows only the right side of his face. Dirac looked rather more resolute in the two chalk drawings by Howard Morgan in 1980, commissioned by the National Portrait Gallery.
The Strangest Man Page 59