Using the prototype machine was no smooth operation. It was comparable with the use of the Robinsons. According to Cicely Popplewell,8 it
… required considerable physical stamina. Starting in the machine room you alerted the engineer and then used the hand switches to bring down and enter the input program. A bright band on the monitor tube indicated that the waiting loop had been entered. When this had been achieved, you ran upstairs and put the tape in the tape reader and then returned to the machine room. If the machine was still obeying the input loop you called to the engineer to switch on the writing current, and cleared the accumulator (allowing the control to emerge from the loop). With luck, the tape was read. As soon as the pattern on the monitor showed that input was ended the engineer switched off the write current to the drum. Programs which wrote to the drum during the execution phase were considered very daring. As every vehicle that drove past was a potential source of spurious digits, it usually took many attempts to get a tape in – each attempt needing another trip up to the tape room.
In fact, writing from the tubes on to the magnetic drum was all but impossible on the prototype. Alan wrote9:
Judged from the point of view of the programmer, the least reliable part of the machine appeared to be the magnetic writing facilities. It is not known whether the writing was more often done wrong than the reading or less. The effects of incorrect writing were however so much more disastrous than any other mistake which could be made by the machine, that automatic writing was practically never done…. Other serious sources of error were the failure of storage tubes and the multiplier….
In the hot summer of 1950 it was not unknown for computer users to be sweltering in 90°F heat, and banging the racks with a hammer to detect loose valves.
The autumn of 1949 saw what was to be Alan’s only titbit of hardware design for the Ferranti machine.10 One of the hardware functions on which he had insisted was that of a random number generator – a feature not included in his ACE design. His own electronic knowledge stopped short of the necessary practical detail, but with Geoff Tootill’s collaboration he was still able to design his own system. It was one that produced truly random digits from noise, as opposed to something like a cipher key generator that would produce apparently random but actually determined digits. (That, if he wanted it, he would surely program for himself.) Perhaps he based his design on the circuit that produced the Rockex key-tapes at Hanslope.
Geoff Tootill was interested in Alan’s ideas, but some of them were particularly impractical in view of the limited time and effort available. There was, for instance, a scheme he devised for computer character recognition, which would involve an elaborate system with a television camera in order to transfer a visual image to the cathode ray tube store, and reduce it to a standard size. Geoff Tootill was probably the most tolerant of such dreams, but to him as to all on the engineering side, Alan Turing was the brilliant mathematician (or so they heard) but embarrassingly half-baked engineer. The year 1949 meant the end of his groping efforts to be the academic engineer; there were few who appreciated that the remarkable thing for a British pure mathematician was not a deficiency in electronics, but the willingness to dirty his hands at all.
Meanwhile the more theoretical side of computer development had become a more public question. In 1948 Norbert Wiener had published a book called Cybernetics, defining this word to mean ‘Control and Communication in the Animal and the Machine’. It meant the description of the world in which information and logic, rather than energy or material constitution, was what mattered. As such it was heavily influenced by the massive wartime technological developments, although the basic ideas, such as feedback, were hardly new. Wiener and von Neumann had led a conference in the winter of 1943–4 on ‘cybernetic’ ideas, but Wiener’s book marked the opening up of the subject outside the narrow domain of technical papers. In fact Cybernetics was still very technical, incoherent, and almost unreadable, but the public seized upon it as a magic key which would unlock the secrets of what had happened to the world in the past decade.
Wiener regarded Alan as a cybernetician, and indeed ‘cybernetics’ came close to giving a name to the range of concerns that had long gripped him, which the war had given him an opportunity to develop, and which did not fit into any existing academic category. In spring 1947, on his way to Nancy, Wiener had been able to ‘talk over the fundamental ideas of cybernetics with Mr Turing,’ as he explained in the introduction to his book.
By 1949 an American supremacy was virtually taken for granted in science as in everything else, and it was a sign of the times that on 24 February 1949 the popular magazine News Review,11 presenting a digest of what Wiener had to say, should explain with pride how British scientists had been able to supply ‘valuable data’ to the American professor when he had flown in. It was as a planet round the Wiener sun that Alan appeared, the photograph of his young and slightly nervous profile standing in marked contrast to the ponderous features of Wiener and the massive visage of the biologist J. B. S. Haldane.
In reality Alan was more than a match for Wiener, and although genuinely sharing many common interests, their outlooks were different. Wiener had an empire-building tendency which rendered almost every department of human endeavour into a branch of cybernetics. Another difference lay in Wiener’s total lack of a sense of humour. While Alan always managed to convey his solid ideas with a light English touch of wit, Wiener delivered with awesome solemnity some pretty transient suggestions, to the general effect that solutions to fundamental problems in psychology lay just around the corner, rather than putting them at least fifty years in the future. Thus in Cybernetics it was seriously suggested that McCulloch and Pitts had solved the problem of how the brain performed visual pattern recognition. The cybernetic movement was rather liable to such over-optimistic stabs in the dark. One story going around, which later turned out to be a hoax, but which found its way into serious literature,12 was of an experiment supposed to measure the memory capacity of the brain by hypnotising bricklayers and asking them such questions as ‘What shape was the crack in the fifteenth brick on the fourth row above the damp course in such and such a house?’. Alan’s reaction to these cybernetic tales was one of amusement.
Another point of difference lay in the fact that Wiener was openly concerned about the economic implications of cybernetic technology. The war, for him, had not changed a conviction that machines should be made to work for people rather than vice versa. His comment that factory robots would put the people they replaced in the position of competing against slave labour, and his daring description of the principle of competition as a ‘shibboleth’, put him on the extreme left of 1948 American opinion. It was no accident that on his visit to Britain Wiener had consulted the left-wing luminaries of science, J. D. Bernal and H. Levy, as well as Haldane.
But the academic debate that followed Cybernetics in Britain was not concerned with this question, nor indeed with anything to do with the use of computers, or the harnessing of wartime technology to peaceful and constructive ends, or the relative merits of cooperation and competition. When the News Review called cybernetics a ‘frightening science’ it was not the economic consequences but the threat to traditional beliefs that it feared. Post-war reaction to planning and austerity, conservative rather than commercial, was reflected in the almost Victorian terms of reference which the intellectuals also accepted. This was true of Alan Turing as much as anyone; these were terms close to his own struggle of the 1930s over problems of thought and feeling. Times had changed, however, and so it was not a bishop but a brain surgeon who led the British intellectual reaction to the claims of machinery to thought. The eminent Sir Geoffrey Jefferson delivered an address,13 The Mind of Mechanical Man, as the Lister Oration on 9 June 1949.
Jefferson held a Chair of Neurosurgery at Manchester, and knew about the Manchester computer development from talking about it with Williams. But most of his impressions came from Wiener, whose emphasis was still placed
on the similarity of the nerve-cells of the brain to the components of a computer.* On this level the analogy was pretty feeble, and not much advanced by Wiener’s comparisons between computer malfunctions and nervous diseases. The Turing ideas of discrete-state machines and universality were required to lend precision and substance to the cybernetic claim. Some of Wiener’s assertions were rather easy to attack; but Jefferson did go further than just knocking them down, playing some strong commonsense cards, such as:
But neither animals nor men can be explained by studying nervous mechanics in isolation, so complicated are they by endocrines, so coloured is thought by emotion. Sex hormones introduce peculiarities of behaviour often as inexplicable as they are impressive (as in migratory fish).
Jefferson liked talking about sex. But his Oration was concluded by flights of rhetoric which only begged the question. An oft-quoted passage held that
Not until a machine can write a sonnet or compose a concerto because of thoughts and emotions felt, and not by the chance fall of symbols, could we agree that machine equals brain – that is, not only write it but know that it had written it. No mechanism could feel (and not merely artificially signal, an easy contrivance) pleasure at its successes, grief when its valves fuse, be warmed by flattery, be made miserable by its mistakes, be charmed by sex, be angry or miserable when it cannot get what it wants.
Jefferson ended by ‘ranging myself with the humanist Shakespeare rather than the mechanists, recalling Hamlet’s lines: “What a piece of work is man! How noble in reason! How infinite in faculty”’, and so forth. Shakespeare was often exhibited in these discussions as proof of the speaker’s exquisite human sensibilities. However, Jefferson had done a good deal to improve upon the ‘piece of work’ himself, not only by mending the broken heads of two world wars but as an exponent in the late 1930s of the frontal lobotomy.
This was the ‘heads in the sand’ argument, resting upon the assumption that a machine, because its components were non-biological, was incapable of creative thinking. ‘When we hear it said that wireless valves think,’ Jefferson said, ‘we may despair of language.’ But no cybernetician had said the valves thought, no more than anyone would say that the nerve-cells thought. Here lay the confusion. It was the system as a whole that ‘thought’, in Alan’s view, and it was its logical structure, not its particular physical embodiment, that made this possible.
The Times14 seized upon Jefferson’s concession that
A machine might solve problems in logic, since logic and mathematics are much the same thing. In fact, some measures to that end are on foot in my university’s department of philosophy [sic].
Their reporter telephoned Manchester, where Alan rose to the bait and chatted away without inhibition:
‘This is only a foretaste of what is to come, and only the shadow of what is going to be. We have to have some experience with the machine before we really know its capabilities. It may take years before we settle down to the new possibilities, but I do not see why it should not enter any one of the fields normally covered by the human intellect, and eventually compete on equal terms.
I do not think you can even draw the line about sonnets, though the comparison is perhaps a little bit unfair because a sonnet written by a machine will be better appreciated by another machine.’
Mr Turing added that the university was really interested in the investigation of the possibilities of machines for their own sake. Their research would be directed to finding the degree of intellectual activity of which a machine was capable, and to what extent it could think for itself.
This embarrassing definition of what ‘the university’ was ‘really interested in’ provoked a swish of the cane from the Catholic public school:15
… If one may judge from Professor Jefferson’s Lister oration … responsible scientists will be quick to dissociate themselves from this programme. But we must all take warning from it. Even our dialectical materialists would feel necessitated to guard themselves, like Butler’s Erewhonians, against the possible hostility of the machines. And those of us who not only confess with our lips but believe in our hearts that men are free persons (which is unintelligible if we have no unextended mind or soul, but only a brain) must ask ourselves how far Mr Turing’s opinions are shared, or may come to be shared, by the rulers of our country.
Yours &c. ILLTYD TRETHOWAN
Downside Abbey, Bath, June 11.
The rulers of Great Britain did not divulge their opinions. But Max Newman wrote to The Times to correct the impression left by Alan’s heady prophecies, dousing them with a laborious explanation of the Mersenne prime problem. Jefferson proved a good publicity agent for Manchester, for The Times published photographs of the adolescent machine, and the Illustrated London News followed on 25 June. By chance, these happened to upstage the grand opening of the EDSAC in Cambridge.
Wilkes’ team had made rapid progress, and had already completed the building of an EDVAC-type computer, with mercury delay line storage, well ahead of any American development. It had a storage capacity of only thirty-two delay lines, and its digit time was two microseconds, twice that of the planned ACE. But it worked; and if the ‘baby machine’ at Manchester was the first working electronic stored program computer, the EDSAC was the first to be available for serious mathematical work.*
Alan attended the inaugural conference, and gave a talk on 24 June 1949 entitled ‘Checking a Large Routine’.16 He described a sophisticated procedure, appropriate for long programs in which it would be easy to lose track of the fate of numbers in store. Illustrating his points, he did some sums on the blackboard, and lost everyone by writing the numbers backwards as he was used to doing at Manchester. ‘I do not think that he was being funny, or trying to score off us,’ wrote Wilkes,17 ‘it was simply that he could not appreciate that a trivial matter of that kind could affect anybody’s understanding one way or the other.’ It was a ‘fussy little detail’, which perhaps masked the irony of the fact that while the EDSAC people had only begun to write programs in May 1949, soon discovering the idea of the sub-routine, Alan had been writing and perhaps checking them for years.
Meanwhile the ACE did survive after all. Alan had resigned at the lowest ebb. Then Thomas, who was in charge of the electronics, resigned, and his successor, F. M. Colebrook, proved to have a very different attitude. In fact, as soon as Thomas was gone, the mathematicians moved into the engineers’ building. Thanks to Colebrook an unheard-of relaxation took place, and the two groups were soon working together in a sort of assembly line. The speed of progress attained in building the machine was comparable with that envisioned in Alan’s original proposal. By mid-1949 they had a delay line working and the wiring of the control was finished in October. The machine, the ‘Pilot ACE’, was based on the Turing ‘Version V’, just as Huskey’s premature effort had been. It retained the ‘distributed’ processing that distinguished it from the von Neumann system which used an accumulator. They also kept megacycle speed, which made it the fastest in the world. Meanwhile Sir Charles Darwin retired in 1949. Max Newman took the view that he had done Darwin a good turn in taking Alan away, and Alan would agree with this. When he went to the official opening of the Pilot ACE in November 1950 he was particularly generous in telling Jim Wilkinson how much better they had done than would have been possible had he stayed. Certainly the Pilot ACE would not have been possible at all had not Alan gone. But he must also have known that it represented only a shadow of his original vision.18
Womersley managed to rewrite the history of the ACE project after Alan had left. For it was Womersley’s story that Colebrook gave to the Executive Committee meeting on 13 November 1949:
Mr Colebrook then referred to the organisational history of the Automatic Computing Engine project. The work on this originated with Dr Turing’s paper … ‘On Computable Numbers with an Application to the Entscheidung Problem’ [sic] and Mr Womersley began thinking about the logical design in 1938 after reading Dr Turing’s paper and after di
scussions with Professor Hartree. Mr Womersley came to the Laboratory early in 1944, and the following year visited the United States to see the Harvard and ENIAC machines. Professor Newman came to see Mr Womersley in 1945 and introduced Dr Turing, who very soon afterwards joined the staff of the Laboratory.
This was the only mention of Alan’s part in the project. The account continued to explain that
In 1946, work on the Automatic Computing Engine was started and it was arranged for the experimental work to be done by the Post Office and the theoretical work, including the programming of the machine, at the Laboratory. Because of slow progress at the Post Office, a section was started at NPL in 1947 to build the ACE machine.
Skilfully passing over the Thomas period, Colebrook described the progress made in 1948 and 1949. He then contrasted the Pilot ACE with ‘the machine originally proposed’, and announced that
Alan Turing: The Enigma: The Book That Inspired the Film The Imitation Game Page 64
