Alan Turing: The Enigma The Centenary Edition

by Andrew Hodges

  With the loss of strategic independence, and the end of imperial confidence, Alan Turing’s country had changed. His old housemaster had declared him ‘essentially loyal’, and in rather the same way an assumed ‘essential loyalty’ had satisfied the recruiters of the new men. It probably never occurred to them that a well-connected English person could take an abstract, foreign idea seriously enough for it to make any difference. Fifteen years later, events had proved otherwise. If the 1940s had made the idea of ‘intelligence’ into something very concrete and definite, the 1950s forced the concept of ‘loyalty’ to an equal explicitness. And the Cambridge which had supplied the intelligence was an unknown quantity in respect of loyalty. This was a time at which Patrick Blackett, once the trusted adviser of an independent Royal Navy, was being pointed out among Manchester University staff as ‘the fellow traveller’.

  Alan Turing, by comparison, was the entirely apolitical person. But he came from the dissenting King’s background; he had supported the ‘very good’ Anti-War demonstration in November 1933. He had never moved in the sophisticated circles of Burgess and Maclean, and had not been elected an Apostle, but connections could easily be found by anyone who chose to look for them. At a time of guilt by association – when there was nothing but association to go on – he was guilty. They had made some incredible mistakes, and how could they be sure Alan Turing was not yet another, given his instructions by the Red Queen twenty years before? What would constitute a proof? It was Wittgenstein’s awkward question, applied to real life. Burgess and Maclean had been absurd and clumsy players of the imitation game – but were there others more skilful, yet to be found out? Even if such gross suspicions had been entirely ruled out, the fact was that by combining and concentrating the two great unthinkables, cryptanalysis and homosexuality, mysteries of ‘stinks’ and ‘filth’ respectively, he had rendered himself a demon, arousing the most primordial insecurities. And it was at a time when British securities had evaporated. The old social discipline offered no defence against nuclear war, but neither did scientific methods offer better than plans for revenge and suicide. Torn between a subservient trust and a resentful anxiety regarding American machinations, to which British power had been surrendered, a panic over spies and homosexuals provided Great Britain with a suitable diversion.

  The tide in the affairs of men had turned in 1943, and by the summer of 1954 had obliterated the patterns drawn in the Second World War. Stalin had gone, but this had made no difference to the system of threat and counter-threat, apparently beyond the control of individuals. A Soviet hydrogen bomb had been tested in August 1953, presenting the possibility of devastation greater than the most pessimistic prognostications of 1939, and of a scale far outweighing that offered by the British bomb tested in October 1952. But it was the American test on 1 March 1954, the 14-megaton blast catching the crew of the Lucky Dragon, that suddenly jolted public consciousness. On 5 April, in a rare Commons ‘defence’ debate, Churchill saw fit to reveal the terms of the 1943 Quebec agreement between Britain and the United States, on which the Americans had reneged, and said:

  No words of mine are needed to emphasise the deadly situation in which the whole world lies … the H-bomb carries us into domains which have never confronted practical human thought and have been confined to the realms of phantasy and imagination.

  What was fantasy and what was reality? There was American pressure on the British to join in a military intervention in Vietnam, after the French defeat on 7 May at Dien Bien Phu. Churchill’s refusal brought about talk of a ‘British betrayal’, and strains to the quid pro quo of the Special Relationship. Fears of a new Asian war were not unfounded; on 26 May an American admiral spoke of a ‘campaign for complete victory’ in Vietnam, including the use of nuclear weapons. A general described using atomic bombs to ‘create a belt of scorched earth across the avenues of Communism to block the Asiatic hordes’. Dulles now said that he was ‘very hopeful’ that the British government would ‘change their attitude’.

  June 1954 was a period of particular uncertainty, with the Geneva talks on Vietnam being compared with those of Munich. Now it was the turn of American city populations to practise taking cover in air raid shelters, while in Britain there was a revival of the Home Guard – recruitment was in progress at Wilmslow during the last week of May. The tension was as great in Europe as in Asia, with West German rearmament being the inflammatory issue. The rules had changed, and the past had changed its meaning. Not only the silver bars had been lost for good; other bridges had been destroyed, and new ones built in solid concrete. Now it was the turn of the U-boat men to be called back, while the hunt for spies and traitors was occupying their erstwhile enemies. It was on 2 June that the newspapers revealed that ‘new man’ at Princeton to be loyal but a ‘security risk’. Robert Oppenheimer, guilty of wrong ideas and associations, was someone that no one could be certain about. And there was another special feature of the newspapers that Whitsun weekend. Faded, stilted, almost embarrassed tributes were being paid to the men who had landed on the beaches of Normandy, exactly ten years before.

  Alan Turing was not an island, but a stray eddy in a sea of troubles. The coroner referred to the ‘balance of his mind’ and to him becoming ‘unstable’. It was an image not remote from his own morphogenetic model of the moment of crisis. As the political temperature rose, his equilibrium would become more and more unstable. The smallest event could have been the trigger. One particular issue would have concentrated his demand for freedom on the one hand, and the implications of past promises on the other. Could he have gone abroad again in the summer of 1954 – when no one knew what might happen next, and in the midst of an official panic over homosexuality? The Foreign Office had been issuing stern memoranda on Soviet entrapment during the past year,60 in parallel with an extension of ‘positive vetting’ on 31 March 1954, and fortified by the disclosures of the Russian defector Petrov. Meanwhile the Montagu trials had shown that fond British beliefs in velvet-glove government were not always to be sustained. There was always the possibility of another case being brought against Alan, manufactured out of an affair long in the past. This was one aspect of the wave of prosecutions now taking place, and one which threatened to drag down friends – even on the merest suspicions and flimsiest allegations. Even the newspapers, if he could bear to read them, could have told him this. He was in a corner. He had always been prepared to confine his fight to his own personal space – the space that others chose to allow him. But by now he was left no space at all.

  E.M. Forster61, outdoing the King’s heresy with grand bravura, had written in 1938 that if he were faced with the choice between betraying his country and betraying his friends, he hoped he would have the courage to betray his country. He would always put the personal above the political. But for Alan Turing, unlike Forster, or Wittgenstein, or G.H. Hardy, it was more than a theoretical question. For him not only had the personal become the political, but the political was the personal. He had chosen and promised for himself in working for the government. The choice for him therefore was that between betraying one part of himself and betraying another part. And however much he wavered between these alternatives, there was a solid logic to the mind of security, one that could not be expected to take an interest in notions of freedom and development. He had no rights to such things, as he would have had to admit. He might have outwitted the Home Guard, but when it came to questions that mattered, there was no doubt that he had placed himself under military law. There was a war on; there was always a war on now.

  Churchill had promised blood, toil, tears and sweat – and this was one promise which the politicians had kept. Half a million of Alan Turing’s compatriots had been sacrificed ten years before, without much choice in their fate; to have the luxury of choice in matters of integrity and freedom was itself a great privilege. Only the ‘heads in the sand’ assumptions of 1938 had allowed him into such a position in the first place, and his position in 1941 was one for which many w
ould have given all they had. Ultimately he could not have complained. The implications had proliferated, and arrived at a remorseless contradiction. It was his own invention, and it killed the goose that laid the golden eggs.

  No one remotely mindful of such considerations could have wanted to make a fuss; and neither in any case could he speak of such things – that was the very point. Only in obscure clues and jokes could they emerge. In March 1954 he sent to Robin four last postcards.· They were headed ‘Messages from the Unseen World’, an allusion to Eddington’s 1929 book Science and the Unseen World. Robin kept only the last three, here shown:

  It would be misleading to suggest that he had made any discovery in these jottings, but the underlying thoughts were in line with the developments of the 1950s and 1960s.

  III. ‘Arthur Stanley’ is Eddington, and the first postcard alluded to cosmological questions. The ‘light cone’ is an important idea in relativity theory. Einstein’s ideas were based on the concept of a point in space-time, this meaning a precise location in space at a precise instant of time. Imagining this as an instantaneous spark, the future ‘light cone’ of such a point is traced out by the expanding sphere of light from that spark.

  By the ‘Creation’ he would mean the ‘big bang’; it had been known since the 1920s that there were models of an expanding universe that agreed with Einstein’s general theory of relativity, and in 1935 H.P. Robertson, whose lectures Alan attended at Princeton, had further developed the theory of them. Unfortunately the astronomers’ observations of the galactic recession did not seem to be consistent with the Einstein theory, and only in the mid-1950s was the discrepancy eliminated. This was one reason why in 1948 H. Bondi, T. Gold and F. Hoyle had suggested a new theory involving ‘continual creation’ which eliminated the ‘bang’. Alan might have heard Gold speak about it at the Ratio Club in November 1951. But apparently it did not deflect him from the earlier view, soon to be established much more firmly.

  The emphasis on a description using light cones was not a trivial insight. Such an emphasis was emerging in a quite different way through the work of A. Z. Petrov in 1954, was taken up by H. Bondi and F. A.E. Pirani later in the 1950s, and entered very strongly into the ideas of Roger Penrose, who in the early 1960s formulated new ideas about space-time. In fact a ‘Penrose diagram’ of the universe would draw it as ‘the interior of the Light Cone of the Creation’.

  IV. Implicit here is the problem of physical determinism. Most physical laws, including Einstein’s, are in the form of a differential equation, relating instantaneous rates of change to one another in such a way that in principle, given the state of a physical system at one time, it can be predicted at a later time by adding up the changes over the period. In the context of cosmology this begs the question of what the ‘initial’ state of the universe was – it was a very Eddingtonian suggestion that the study of the differential equations of physics could only be half the story. Here again, the question of the nature of the initial ‘big bang’ was to be of growing significance in the renaissance of relativity theory.

  V. Again the allusion is to the problem of physical prediction – the wave functions somehow determining the events perceived as the pantomime of macroscopic life – and again the emphasis is on a description in terms of light rays. But the ‘hyperboloids’ suggest some quite novel geometric picture of his own, lost without trace.

  VI. The reference to ‘founts’ suggests that he was thinking of describing the different elementary particles in terms of their corresponding symmetry groups–again in the mainstream of developments, although the picture as it unfolded in the 1960s was far more complicated than anyone would have known in 1954.

  VII. He was certainly not the first to think that electric charge could be interpreted in terms of rotations, and his formula was too simple-minded. But 1954 saw the renewal of interest in ‘gauge theories’, which generalised this basic idea.

  VIII. Often his letters closed with a brief line of personal comment, and this was surely the case here. There was certainly nothing new or speculative in scientific terms in this ‘message’, an allusion to the well-established Pauli Exclusion Principle. Back in 1929, when he read what Eddington had to say about the electron, Alan had noted the idea that the electrons of the universe had to be considered en-masse, not singly; the Pauli principle described an observed restriction on the collective behaviour which roughly speaking meant that no two electrons could be in the same place. Thus in each atom, the electrons would be stacked neatly in separate shells and orbits. As indeed he might have joked in 1929, it was like the House system that kept the boys from associating too freely. For their own benefit, of course: Don’t you see, Dr Turing, we have to do this for your own protection....

  The old Empire was giving way to the institutions of Oceania. None of Alan Turing’s friends saw this as a background that might be relevant to his death, nor saw him as playing the role of Casablanca after all. Not for about fifteen years would the various elements involved become mentionable at all, and even then no one could begin to put them together. There was no hushing-up operation in 1954 – it was not necessary, for no one thought anything nor asked any questions. The Wicked Witch of the West was caused no embarrassment, for the friends of Dorothy had nothing to go on. Few people on 7 June 1944, seeing the cycling civilian boffin, could have imagined a connection with the news of the great invasion: they did not need to know, nor want to know. Ten years later to the day, the links were literally unthinkable, and the death came as an individual hurt and loss, without suggesting any wider significance. Jung said:62

  Modern man protects himself against seeing his own split state by a system of compartments. Certain areas of outer life and of his own behaviour are kept, as it were, in separate drawers and are never confronted with one another.

  Modern men had to protect themselves particularly carefully when they were confronted by Alan Turing, and they kept the compartments completely separate. So perhaps too did Alan Turing, when confronting his own situation.

  Behind the singleminded Shavian figure that he cut, especially after the war, acting out in public a set of ideas with relentless intensity, and going to the stake like a modern Saint Joan, there had always been a more uncertain, contradictory person. Doubting Castle and Giant Despair had been his favourite passages in The Pilgrim’s Progress as a small boy, and his part in progress of mankind had been in keeping with them – the delectable mountains being few and far between. In particular there lay the uncertainty of all his relationships with institutions, neither fitting in, nor presenting a serious challenge. In this respect he shared something with many people deeply attracted to pure mathematics and science – never sure whether to regard social institutions as Erewhonian absurdities or as plain facts of life. Making a game out of anything, like G.H. Hardy (and like Lewis Carroll), he reflected the fact that mathematics could serve as protection from the world for one who was not so much blind to worldly affairs as only too sensitive to their horror. His off-hand, self-effacing humour also shared something with the response of so many gay men to an impossible social situation: in some ways directing a bold, satirical defiance at society – yet ultimately resigned to it.

  For Alan Turing these elements were aggravated by the fact that he never quite fitted into the roles of mathematician, scientist, philosopher or engineer – nor into the tail-end of the Bloomsbury set, nor indeed into any kind of set, even the Wrong Set. It was often a case of Laughter in the Next Room for Alan Turing, for people never knew whether to include him or not. Robin Gandy wrote63 very soon after his death of how ‘Because his main interests were in things and ideas rather than in people, he was often alone. But he craved for affection and companionship – too strongly, perhaps, to make the first stages of friendship easy for him…’And he was more alone than anyone could ever see.

  A self-taught existentialist, one who had probably never heard of Sartre, he had tried to find his own road to freedom. As life became more complicated it b
ecame less clear where this should lead him. But why should it have been clear? This was the twentieth century, in which the pure artist felt called upon to become involved, and which was enough to make any sensitive person acutely nervous. He had done everything he could to restrict his involvement to the simplest sphere, as he had also tried to keep true to himself, but simplicity and honesty had not protected him from the consequences of that involvement: far from it.

  The British university world was as well insulated from the twentieth century as anyone could hope for; and so often it saw his eccentricities, not his vision, offered vague tributes to cleverness, not serious criticism of his ideas, and remembered the bicycle stories rather than the great events. But although nothing if not an intellectual, Alan Turing never truly belonged to the confines of the academic world. Lyn Newman, who had the advantage of seeing that world at close quarters but from outside, articulated64 more clearly than anyone else this lack of an easy identity; she saw him as ‘a very strange man, one who never fitted in anywhere quite successfully. His scattered efforts to appear at home in the upper-middle class circles into which he was born stand out as particularly unsuccessful. He did adopt a few conventions, apparently at random, but he discarded the majority of their ways and ideas without hesitation or apology. Unfortunately the ways of the academic world which might have proved his refuge, puzzled and bored him…’ There was an ambivalence in his attitude to what was, despite all its concomitant deprivation, a privileged upbringing: he jettisoned most of the paraphernalia of his class but in inner self-confidence and moral responsibility remained the son of Empire. There was a similar ambiguity in his status as an intellectual, not only in his disdain for the more trivial functions of academic life, but in the mixture of pride and negligence with which he regarded his own achievements.