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Strachey Lecture: The Once and Future Turing · Strachey Lectures

• 0:10
  Good evening. Welcome, everybody, to the showdown in theatre on a beautiful autumn evening in Oxford.
• 0:16
  My name's Mike Wooldridge.
• 0:17
  I'm the head of Department of Computer Science and it's my pleasure this evening to host our Michaelmas term Straight to Lecture,
• 0:24
  which is our distinguished lecture series. Before I do that, though, I should point out the Straight G lectures are a celebration.
• 0:31
  They're a celebration of science, sometimes obscure science, sometimes somewhat more accessible science.
• 0:36
  But we have another reason for celebration today.
• 0:40
  Some of you may have seen in the press last week that we were delighted to be able to welcome back to
• 0:45
  Oxford as a member of the Department of Computer Science and as a fellow at Christchurch College,
• 0:50
  Sir Tim Berners-Lee, and as you will all know, is the inventor of the World Wide Web.
• 0:55
  Tim is actually with us in the audience tonight with his with his wife, Rosemary and Tim.
• 0:59
  Rosemary. You are most welcome back to Oxford. So on to this evening's business lecture this evening is Andrew Hotchkiss.
• 1:20
  And I asked Andrew to give me some short biographical details, and this is what he actually told me to tell you.
• 1:25
  He's a senior research fellow in the Mathematical Institute. He's been a long time fellow and tutor in mathematics at Wadham College.
• 1:32
  His research was in mathematical physics, I think twist a theory under the supervision of Roger Penrose,
• 1:38
  with whom he has a close relationship to the present day. He was given an honorary doctor of Science at the University of Edinburgh in June last year,
• 1:46
  and he also tells me he appeared on stage with the Pet Shop Boys in the Albert Hall in July 2014.
• 1:54
  In all other respects, a distinguished but in some sense unremarkable career for an Oxford Don,
• 2:03
  the kind of career that you would expect an Oxford Don to have.
• 2:07
  But the reason that Andrew's here tonight is that in the late 1970s and early 1980s, he did something truly remarkable.
• 2:15
  He wrote a book and this is it.
• 2:18
  This is my copy of it. I've treasured this book for 30 years,
• 2:21
  and I've just Andrew's I've just shown it to Andrew and he's told me this was a particularly poor edition of the book and very bad value for money.
• 2:29
  But nevertheless, I did Treasury. I actually wrote rather quaintly.
• 2:32
  I wrote the date inside May 1985. I bought this copy of the book.
• 2:36
  The binding is not lasted as well as the words inside it, and the book is the story of Alan Turing.
• 2:43
  And what's important to remember is that before this book appeared, Turing's name was completely unknown outside computer science.
• 2:50
  And the remarkable things that he did in his life were completely unknown outside the field of computer science and and mathematics.
• 2:59
  I read a review of this book and was moved to order it from my bookshop.
• 3:03
  The town of Hereford, where I grew up, didn't stop this kind of book in the mid 1980s,
• 3:07
  so I had to order it and it made a tremendous and lasting impression on me.
• 3:11
  And indeed it's one of those books, as I say, that I've treasured throughout my life.
• 3:15
  So why did it make such a lasting impression on me? Well, firstly, it is a fantastic book.
• 3:21
  It is ranked as one of the greatest scientific biographies of all time.
• 3:25
  I'm assuming you're all you've all Reddit's. If you haven't read it, you should do so.
• 3:30
  It is your duty to do so. You will have the opportunity, in fact, to get copies of it.
• 3:35
  And Andrew has indicated he'd be happy to sign copies afterwards.
• 3:39
  But it is a great scientific biography and rarely do scientific biographies get
• 3:44
  under the skin of the science and the thinking that led to scientific innovation.
• 3:48
  So that's the first reason that it's remarkable.
• 3:54
  The second reason it's remarkable is, as I say, that it gave the world the Turing story for the first time before this book.
• 4:01
  There was no Turing story. And when I read the story, I'd never heard of Turing's life.
• 4:07
  And I was shocked and appalled at what happened to Turing in the later stage of his life.
• 4:14
  And I was always brought up to think that this country was on the right side of history, that basically we were decent people who did the right thing.
• 4:21
  And I was astonished to discover the kinds of things that happened in the 1950s in this country.
• 4:26
  And it opened my eyes.
• 4:28
  It gave me a burning sense of injustice and unfairness and a sense of injustice and unfairness that stayed stayed with me ever since.
• 4:36
  So the arc of human history tends towards justice, we are told.
• 4:42
  Well, if it does so, then from time to time, it needs some very big signposts along the way to point it in the right direction.
• 4:50
  The Turing story, I think, is exactly such a signpost.
• 4:55
  We read just the other week of in the press of the Alan Turing Law,
• 5:00
  thousands of gay men to be pardoned if they were prosecuted for crimes that are now no longer regarded as crimes,
• 5:08
  whatever one might think of that, whether it's a token gesture and so on,
• 5:11
  at least it suggests that our thinking as society is heading in the right direction.
• 5:17
  I don't believe I believe sorry that the Turing story is actually an important part of that of that trajectory.
• 5:26
  It was Andrew that gave us that story. We wouldn't have it in the form that we have it today.
• 5:31
  And Andrew, it's really all due to the work that you did in that book.
• 5:34
  So I'm very, very pleased to welcome you to give this evening straight to your lecture.
• 5:38
  Thank you. Well, thank you very much for that.
• 5:52
  I'm not sure I can follow that very easily. And I think you've done a spoiler.
• 5:56
  I think you've given away the ending of I will be talking a little bit at the end of that,
• 6:02
  more than I usually do about the events at the end of Alan Turing's life,
• 6:05
  because I think there is a a need for that, especially when it's been in the news so much in the recent period.
• 6:12
  But I'm going to try and give an overview of his whole scientific life before I get to that.
• 6:19
  And also, I should remember, while welcoming you that I'm being watched by people who see this as a podcast.
• 6:26
  And the podcast people may not know that we're in the wonderful setting of the Sheldon
• 6:30
  Ian Theatre and that this goes back to the scientific revolution of the 1660s.
• 6:35
  And I would like you to see Alan Turing, who lived from 1912 to 1954,
• 6:40
  as as as in that great stream of life, drawing on the past and reaching into our own present and future.
• 6:50
  Turing didn't have a strong personal connection with us here in Oxford, but he did have a link with Christopher Straight G,
• 6:56
  who became the founding figure of computer science here and whose name is remembered, of course, in this lecture series.
• 7:03
  Some people here may also have known Robin Ghandi, Major Oxford figure in mathematical logic.
• 7:09
  He was Turing's close friend and first student. And there are many more threads in this great intellectual web linking past and present.
• 7:17
  Some of these are brought out in a recent book, not my book, but another book called The Once and Future.
• 7:23
  Turing with contributions from leading people in a whole number of fields that Turing touch.
• 7:28
  One of these, Professor Scott Aaronson, was a Christopher Straight G.
• 7:32
  Lecturer last year, and I'm very honoured that this talk is the successor to his.
• 7:37
  It's my pleasure that other contributors Sir Roger Penrose and Dr. Tom Willey,
• 7:41
  representing the mathematical biology group Paradox, are also here, along with such fantastically distinguished guests as Michael,
• 7:49
  as has mentioned now of all these many threads, of course,
• 7:53
  the central one is the emergence of digital technology and the dominating role of the electronic computer.
• 8:01
  And of course, even just the podcasting of this talk, all the projection onto this screen, something we now take for granted depends on it.
• 8:09
  And all this leads me to choose the starting point for the story, which is not the obvious one,
• 8:14
  not the beginning, the usually begin and not the end, although it's extremely interesting.
• 8:19
  But it points in the middle 1951 because that's when Christopher Straight, she met Turing at the early Manchester computer laboratory.
• 8:29
  1951 was the end of the post-war period.
• 8:33
  It was the Festival of Britain. It was the start up for modernism and the flashing lights of those first computers
• 8:40
  and a very old fashioned class bound Britain was was an inspiring aspect of it,
• 8:46
  I think. Christopher Street, you saw this very clearly and while a maths master at Harrow School,
• 8:51
  he wrote this hearing about many ideas, including developing high A-level languages.
• 8:57
  And you won't be able to read his typescript, but there are two words in there programme and utopian,
• 9:03
  and his idea was a programme to write programmes at a lower level.
• 9:08
  Then a utopian idea, but something which advanced people like him was seeing was possible and indeed of course came about.
• 9:15
  After further contact straight, she arrived in Manchester with an advanced programme to try out on their computer.
• 9:21
  To everyone's amazement, it worked perfectly at the first attempt, never been seen before, and then gave a rendition of God Save the King.
• 9:30
  That was the first that was the start of serious operating systems, but also of computer based media.
• 9:37
  The Manchester computer played Jingle Bells to the Nation on the radio at Christmas 1951.
• 9:43
  And you may have seen recently that an audio recording of the Manchester Computer's tune playing has been recovered.
• 9:50
  Street is a love letter programs which had generated syntactically correct random sentences,
• 9:57
  also got into the media and served to give a quite new public picture of what computers could be all about.
• 10:04
  Right. As Michael mentioned, there would be a day markings, Christopher Street centenary next month.
• 10:09
  So I don't need to say more about him, but I will just say that his draughts playing programs complemented the chess playing that Turing
• 10:16
  had already started and gave a first stab at machine intelligence all of these exercises.
• 10:22
  So this is what I want to emphasise illustrated Turing's concept of the computer as a universal machine.
• 10:29
  That was something that was by no means familiar in 1951, and it pushed out the boundaries of what could be expected of computers.
• 10:37
  Now, Turing situation at Manchester. I mean, why was he there?
• 10:40
  What was he doing? Well, it came about because of having had that idea of a universal machine back in 1936.
• 10:48
  In fact, the Manchester. A computer as working in 1948 had been the world's first practical embodiment of his idea.
• 10:56
  So what we're doing now is we're going back to the pre-war pre-computer world and see how the computer came into being.
• 11:04
  Taking Alan Turing story along with it. So back to 1936, Alan Turing at Cambridge and specifically a fellow of King's College, Cambridge.
• 11:16
  He was not a university lecturer and he was just 24.
• 11:20
  Now, he would have been seen as a pure mathematician in Cambridge in the thirties,
• 11:24
  but in fact he was in no way restricted by such Cambridge compartments as a student.
• 11:30
  In 1932, for instance, he was reading John von Neumann's New Mathematical Foundations of Quantum Mechanics.
• 11:38
  More precisely, of course, he was reading the original German.
• 11:41
  And you should remember that until Hitler took over and wrecked everything, Germany was still the scientific world centre.
• 11:47
  Turing's early work largely derived from that German speaking mathematical world, and he was hiking in Germany several times as well.
• 11:55
  And the greatest thing was his following up of Kurt Gödel in the revolutionary work of 1931, which showed up the incompleteness of axiomatic systems.
• 12:04
  He did this after attending the 1935 Cambridge Lectures on Mathematical Logic by Max Newman.
• 12:11
  Turing's now very famous work Defining Computer Ability was essentially complete in 1936, and this is the title page of it here,
• 12:22
  a title which would have been completely incomprehensible to almost everyone in the world,
• 12:27
  not helped by having a very long German word in the middle of it. This is not how to make a career, really, but this is what he did.
• 12:36
  And doing this problem, the decision problem of Hilbert is the German word and its curiosity that the very word application comes in the title.
• 12:47
  I mean, is that curiosity? Because an application now means a computer program.
• 12:51
  It's the word people use. And this paper actually effectively defined such programs.
• 12:56
  They are what came to be called Turing Machines.
• 12:59
  A universal machine can play any program, and so corresponds to a modern computer of the kind which then didn't exist.
• 13:07
  So I'll just point to some words in that like application on another page, the word the universal computing machine comes into the picture.
• 13:17
  And these interesting words, it is possible to invent a single machine which can be used, I mean, to do to do any application.
• 13:27
  And universal machines are now carried in your hand and passed at a click from one application to another.
• 13:33
  But we should note that actually the app, the application theory was talking about in this work was not an app.
• 13:40
  If the whole point was, it's not a program. His proof showed that there could not be no program.
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  That was so the decision problem that Hilbert had defined a problem which in effect requires the understanding of all of mathematics.
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  And this is one reason why this deep paper is not just about techniques of computing,
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  but has a much greater significance, the absolute limitations of the computable.
• 14:03
  On another page, a mathematical joke, very typical of Turing is talking about, well, you might imagine doing mathematics.
• 14:12
  And at a certain point you arrive at theorem number 157767733, four, four, three, four, seven, seven.
• 14:19
  That is a mathematical joke, if you like. But actually, of course, thinking in those terms gets him into the mental framework of a programmer.
• 14:28
  You programmer of the computer has to allow for that that such things have to be you have to think of the computer,
• 14:36
  how the computer will read the data and and this and do so systematic way.
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  So he invented in this paper the whole mentality of computer programming.
• 14:47
  And of course, it's not didn't come out of nowhere. It came out of the rigour of mathematical foundations.
• 14:52
  On another page, you see it was not just the mind of the programmer he was thinking, but we see these words state of mind to come out.
• 15:01
  There's an analysis here of the action of the human mind and what it is that a person is doing when they're computing.
• 15:08
  This meant going outside mathematics. I mean, he's way outside the box is not what maths people were really supposed to be doing.
• 15:16
  And there's a question here, where did it come from? What were the origins of this?
• 15:21
  Well, here it's we're in the dark ages. I mean, it's like the once and future King Arthur.
• 15:26
  There's very, very little written evidence. There are no precursor papers and no notes.
• 15:32
  We do just know of his earlier fascination with a question of mind and matter,
• 15:37
  which had taken him first to John von Neumann quantum mechanics in 1932, and then into the foundations of mathematics.
• 15:46
  A few more things about that that that history. That's a.
• 15:49
  Biologist Max Newman's lectures of 1935, one of the key stimulus.
• 15:54
  But there's been new work on the remarkable background to Max Newman's own interests,
• 15:58
  showing how exceptional it was not at all the Cambridge mainstream.
• 16:03
  There's also new work which gives it shows Turing serious interest in a different but related problem that of characterising random real numbers.
• 16:13
  He had a friend, David Champion, who was in the same matter at King's, who published one an undergraduate in 1933.
• 16:20
  The observation that a certain rather curious real number has some provably random characteristics in base ten.
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  Turing took this up and is now seen to have gone a long way with generalising it,
• 16:32
  although he never published anything, it was in that same 1936 period.
• 16:37
  So there's another ingredient which might explain Turing's very individual formulation of Hilbert's problem in terms of computing numbers.
• 16:45
  Well, I'm not really explaining that.
• 16:47
  What I want to say is that there was a very wide range of inputs, the Turing story wide in mathematics and in sciences and in philosophy.
• 16:56
  But he was not to do with the actual calculation of numerical problems in this very abstract context.
• 17:03
  The universal machine arises like a by-product is on the side.
• 17:07
  And yet he certainly appreciated and discussed with his friend David Champion on this very striking property of his invention,
• 17:15
  a single machine that could do anything.
• 17:18
  He was very right to look very please in this in the in the passport photo, which unfortunately I've got missed out but said never mind.
• 17:28
  Well, we'll come to a nicer one with him here for showing him at Princeton, which was what the passport was for.
• 17:34
  He went off to Princeton, which since 1933 was the New World Scientific Centre, in effect, and arrived there and in 1936.
• 17:44
  So that's we have a snapshot of Alan Turing course in a seminar at Princeton is not a selfie, but it looks a bit like that.
• 17:55
  And notably, he's a little bit at the edge of the picture, which is I think is about the correct place.
• 18:01
  He was not he didn't put it in self forward as a central person.
• 18:06
  He was someone who was always a little bit on the edge of the group.
• 18:10
  He's also looking remarkably smart, actually. I mean, the graduate students don't wear ties nowadays and nor that he usually so I'm
• 18:17
  not quite sure why he was looking quite as as brushed up what he was doing.
• 18:22
  There was a Ph.D. on Ordinal Logics, supervised by the American logician Alonzo Church.
• 18:29
  And that's I mean, a source of a huge amount of post-war thinking about the nature of the computable.
• 18:35
  It's nothing to do with practical computing, but on the side, he certainly was interested in implementing computing.
• 18:44
  You couldn't have built a universal Turing machine with 1936 technology, but you he applied his interest in implementation to smaller projects.
• 18:54
  Very unusual, again, for someone who's supposed to be a pure mathematician, got his hands dirty with it.
• 19:00
  And this in particular, he had a machine for computing the Riemann Zeta function on the critical line using various areas,
• 19:10
  and that was pursued further in 1939.
• 19:13
  And the point of this document here is it shows the interesting figure of £40, which you got from the Royal Society for this.
• 19:21
  I think that's the only really successful grant application he made.
• 19:25
  I don't think he was a model for research proposals, but not a role model for modern students or postdocs.
• 19:34
  But anyway, he managed and another machine he got no support for at all was absolutely his own thing.
• 19:41
  And this was the cipher machine. The cipher machine.
• 19:44
  We don't know quite what it was, but it was electromechanical. And that raises another very interesting question.
• 19:50
  How did he get into the world of codes and ciphers?
• 19:54
  Well, his idea in 1937 there at Princeton was an idea which would have to do with beating Germany if war came.
• 20:02
  So he said also, he said it arose as a by-product of thinking about abstract compatibility.
• 20:09
  In fact, he said that even back in 1936, right away now this scheme was put to the British governments in the summer of 1938.
• 20:18
  So this was the beginning of a very big story. He was pushing as an open door for two reasons.
• 20:25
  The first is that JCS, as it then was, and I'll call it HQ,
• 20:30
  because that's the same thing now, was actively recruiting mathematicians for the first time.
• 20:36
  And secondly, what you might call the liberal elite was at work for him a seamless interface between King's College and government.
• 20:46
  John Maynard Keynes. The Economist. You can't get. Liberal elite than that was in charge at a very powerful figure at King's College.
• 20:55
  And he was very familiar with hearing and with a department that had broken the codes in the First World War when actually Christopher Street,
• 21:03
  his father, Oliver, was one of the World War One codebreakers.
• 21:08
  In 1938, a contemporary of Oliver Straight is still when Knox was.
• 21:14
  This was one of the senior people in the department. He was a personal friend and indeed ex-lover of Kansas.
• 21:21
  Other King's fellows were joined there as well. So it was an easy transition for Turing to take.
• 21:27
  No mystery at all. But their main problem was the famous Enigma machine.
• 21:34
  And say a little bit about this, but not how it works.
• 21:37
  I'm not going to go on about how the rotors were and everything. But one thing I will say is often called this Nazi enigma machine.
• 21:45
  Actually, it wasn't Nazi at all. Ironically, it was one of the few things the Nazis retained and trusted from the Weimar Republic.
• 21:55
  It didn't change it from the adaptation that was made in 1931.
• 22:00
  European sons, whole level of it.
• 22:02
  It was much better represented by the Polish mathematicians who did work on breaking this machine and arrived at mechanical methods for for doing so.
• 22:13
  In July 1939, they gave vital revelations to the British and French who were behind on this, and the ball started rolling very quickly.
• 22:23
  War was declared on 33rd of September 1939, and Turing started at Bletchley Park, the new wartime headquarters, the next day.
• 22:34
  It actually wasn't new. It wasn't new place to him. He'd visited it a year earlier when the organisation surveyed it for suitability.
• 22:41
  I mean he was already one of the team. But other mathematicians, particularly Gordon Welchman and algebraic Germans, joined up at this point as well.
• 22:50
  It was very senior common room sort of atmosphere and Alan Turing wrote a letter back to King's about dealing with Knox, being his boss,
• 22:58
  a sort of joke that really and it wasn't the boss and type of relationship, but that was that's where they were at Bletchley.
• 23:09
  In fact, you can see the buildings where they worked and the left hand one, the cottage in the stable yard is still there.
• 23:16
  Now, in fact, this is an opportunity to say how much there is to see both preserved and displayed at the Bletchley Park Museum.
• 23:28
  And the other building is a pub where he lived. No.
• 23:32
  I wanted to draw attention to the text here, which has an extremely important date of 1st of November 1939, Turing and Welchman.
• 23:43
  So early, I mean, it's just a few weeks into the war and hearing in a Welshman had immediately had their way
• 23:49
  as mathematicians and an extraordinary new building machine was already under construction.
• 23:55
  Here in this text, it's actually described as a a super bomb machine, which is a great name for it.
• 24:06
  They didn't keep it, but it was a good name for it because it was a far larger than the bomb of the Poles.
• 24:13
  And that was essentially Turing's idea of the Welshman had extremely important parts in it later on for improving it.
• 24:24
  Some people may know something about this.
• 24:26
  I won't try and explain how it worked, but from a computer point of view, it's important to say that it was absolutely not a computer.
• 24:33
  It was an algorithm. It embodied an algorithm. It's nothing to do with universality at all.
• 24:39
  Now it would be an app and it did something which is comparable with solving tens of thousands of Sudoku puzzles in real time,
• 24:51
  very, very quickly, many times a second, which was pretty amazing thing to be able to do in 1939 technology.
• 24:59
  And that was the brilliance of Turing's both his logic and his experience with the machine building,
• 25:05
  to say that this could be done but done so quickly. The first one was built at Letchworth over the winter of 1930 940,
• 25:14
  and it was working in March 1940 before Churchill became prime minister, which a lot of people don't appreciate.
• 25:22
  This was all a triumph of the Neville Chamberlain regime. It was called victory.
• 25:28
  But victory would have seemed very far off at that point. Here's a picture of it.
• 25:34
  And underneath the picture of it is a little sketch of that during his own
• 25:39
  writing for explaining the sequence of logical deductions that makes it work.
• 25:45
  Now, that wasn't enough. It had to be surrounded by a host of other methods and a special algorithms.
• 25:55
  And the Naval Enigma messages were much the hardest to deal with, also the most vital.
• 26:02
  Turing took that on, really against the odds, and that was his most individual contribution.
• 26:07
  He wrote up the Bayesian probability theory, which he developed for this, and that's a little segment of it.
• 26:14
  This paper, incidentally, was only released by GHQ in 2012.
• 26:21
  I don't know why, but it was kept back for a very long time.
• 26:26
  Well, you can see things about, yeah, long odds he liked and you can see lots of 20 sixes, which have to do with alphabets.
• 26:35
  This theory was probably the deepest contribution.
• 26:39
  It wasn't just to do with Enigma. It was used for all sorts of different other cipher purposes.
• 26:43
  And so it went into the purposes for which the famous electronic colossus was used later in the war,
• 26:49
  and its concept of weight of evidence was essentially equivalent to Shannon's measure of information.
• 26:56
  The story after 1941 was very much dominated by the industrial scale of the war.
• 27:03
  So over 200 of these machines were built eventually, and this went well beyond the power of British industry to cope.
• 27:10
  And the Churchillian part of it, really not the starting off part, but the continuing sustained part of it,
• 27:17
  of course, meant giving way to the United States, but trying to retain some British influence.
• 27:22
  That was part of Turing's role, very important. From November 1942 to March 1943, he went on a solo top level technical liaison in the United States,
• 27:34
  setting up the basis for what is now really the NSA GHQ relationship,
• 27:39
  a very tricky diplomatic mission you will see on these and many went various places,
• 27:46
  Washington and Dayton, Ohio, where the new machines were being built by the Americans.
• 27:52
  And New York, where the Roosevelt Churchill radio link was being built at Bell Laboratories speech incitement was especially secret,
• 28:02
  and the United States demanded that he keep things secret from the other Brits when he got back.
• 28:07
  Yeah, but he ran into a lot of problems here. You can see the stories here.
• 28:11
  He was kept on Ellis Island because he didn't have the right papers.
• 28:15
  He was told that he was going to have access and then it was withdrawn and so forth.
• 28:19
  He took a very dim view of this being messed up by security rules, and this was not his thing at all.
• 28:25
  I mean, he liked working with the people on the actual stuff, but this was it was a very annoying nevertheless.
• 28:32
  It introduced him and this is the important thing for the future story.
• 28:35
  This is what introduced him to Hands on electronics.
• 28:38
  It was the speech incitement question. This was the key to the future.
• 28:42
  This is how logic and electronics first came together.
• 28:47
  Well, he was able to work on that when he got back to Bletchley because Hugh Alexander, his deputy, had taken over the Naval Enigma section,
• 28:55
  and Turing went off to a smaller base, Hounslow Park in North Buckinghamshire, where he had a little laboratory.
• 29:04
  And there with one assistant, Donald Bailey, he built a what's called the Delilah machine, which is this small scale speech decipherment thing,
• 29:18
  I mean, not done for transatlantic communications, but the more modest but with very good security.
• 29:24
  And this gave the exposure to some serious electronics with his own hands.
• 29:29
  And it was also effectively practice for what at some point he must have decided it was the thing to do,
• 29:36
  which was to realise the universal Turing machine idea in electronics with the speed and reliability of the cutting edge digital electronics,
• 29:45
  which very few people but he knew about at that point.
• 29:50
  Again, we don't know. We didn't mean the Dark Ages. Again, there must have been a point where he saw he could do this and we don't know when it was.
• 29:57
  But this is at Denslow Park is where all this emerged.
• 30:03
  Von Neumann got in first in June 1945 with a plan for electronic computers, the Ed VAC report,
• 30:10
  and that's generally regarded as the foundation origin of modern computing.
• 30:15
  And so Turing, you know, missed that.
• 30:19
  But on the other hand, the American emphasis gave the Brits very good reason to compete with the U.S. and that everything went right.
• 30:27
  At first they looked at Turing and appointed him to the National Physical Laboratory at Teddington in south west London,
• 30:34
  and that's where he produced the first detailed computer prospectus,
• 30:39
  of which this is one page here, not an illuminating page to I mean,
• 30:43
  it's just to illustrate that it was done in detail and all aspects of the computer from its use and its rationale to detailed construction,
• 30:54
  had a striking list of examples of diverse applications, including a suggestion for artificial intelligence,
• 31:01
  something he'd become very keen on actually in the course of the war,
• 31:05
  and probably stimulated by the fact that algorithmic methods, as they'd used in the codebreaking, had been so incredibly successful.
• 31:14
  He was actually it was mentioned in the press as being the bright young fellow who was doing this thing for the new British triumph.
• 31:24
  He was probably more in the press for his amateur athletics because he was very keen on long distance running at the same time.
• 31:30
  These two things actually came together in in Boxing Day 1946,
• 31:36
  the sports reporter of the Evening News asked him about the electronic brain was his idea,
• 31:42
  and Turing said, well, the Americans had done the donkey work on it, a somewhat ambivalent tribute.
• 31:50
  And I think the only time he ever really commented on the big question of.
• 31:54
  Priority, which was still engaged, is a lot of people now on the whole, he didn't care very much about that.
• 32:00
  He always mentioned the 1936 origin of the ideas, but he never pressed the sense in which there'd been a line of development into computer,
• 32:11
  electronic computer, or certainly not his leading part of it.
• 32:14
  Well, a cut down version of the automatic computing engine, as it was called, was, in fact, completed in 1950.
• 32:22
  And Christopher Strictures first programming in 1951 was for it.
• 32:26
  But by that time, impatience with the NPL Turing had moved to Manchester.
• 32:31
  He started there in October 1948, after that June 1948, working off a tiny prototype, demonstrating his principle of the stored program.
• 32:43
  And that is the there's the early first working a manchester computer, which, again, is a very important moment.
• 32:53
  It wasn't Turing's moment. I mean, Turing on the whole, doesn't get as much credit as he should, I think, although,
• 32:59
  see, he doesn't get as much attention as it should as being one of the first computers.
• 33:04
  But during his connection with the Manchester computer tends to be overstated.
• 33:08
  I mean, you might even the read as he built it or something like that. He didn't he didn't even design it.
• 33:13
  What is important is that he and Newman told the electrical engineers what a computer was.
• 33:19
  It was the whole idea of a stored program embodying the universal machine idea.
• 33:26
  The media had caught on very quickly to the prospect of computers.
• 33:31
  There were a lot of talk about electronic brains rivalling human capacities right back in the 1946, 47, 48 period.
• 33:40
  And Turing rose to this.
• 33:42
  And in, for instance, in 1949, interviewed by The Times, he read it, he just said, oh, we're finding out if the machine could think for itself.
• 33:52
  This was not at all the line that was approved of by by Manchester University.
• 33:58
  I think nowadays they'd be very glad of that sort of a press release coverage.
• 34:02
  But in those days that was thought, not the thing, but it led to much stimulating interdisciplinary and philosophical discussions at Manchester.
• 34:13
  And it was after that that his most celebrated paper on artificial intelligence,
• 34:18
  the paper in the Philosophical Journal in mind of October 1950 called Computing Machinery and Intelligence that came out of these discussions.
• 34:29
  And of course, if you've seen it, you'll know that it's written to attract a wide number of people.
• 34:33
  It's not it's not just for experts. It's full of cultural references, mildly risque jokes, including the Imitation Game of Turing Test,
• 34:43
  introduced as a parlour game with ludicrous text message conversations.
• 34:47
  But behind it is a serious question of how to give an objective characterisation of intelligence.
• 34:53
  And there's much more in it, too. Although it's most famous for that test idea,
• 34:57
  it has this great content of exhibiting the new model of computer ability, the idea of a universal machine,
• 35:05
  and even the bit about the relationship of computer ability to physical law, which is a question which he just started to get going on.
• 35:13
  Also constructive ideas for artificial intelligence, both neural networks and top down programming.
• 35:20
  He said both should be tried and famously gave a cautious 50 year prophecy, but also has this subtext about Alan Turing, which is saying, I am human.
• 35:31
  I know what real intelligence and real life involves that made him an attractive character and speaker.
• 35:40
  And that brings us back to 1951 where we started.
• 35:43
  He was asked to give a third programme radio talk despite not being a very fluent speaker.
• 35:51
  And in fact, you'll see the BBC producers report did credit.
• 35:55
  They had a lively mind, the BBC thought. But he did have this hesitation in his speech.
• 36:02
  I didn't make him a media guru immediately, but nevertheless he was on the radio.
• 36:07
  And it was that radio talk in May 1951 that Christopher Straight she heard,
• 36:13
  and that's what got his career going by writing after Turing at Manchester and with a draughts, playing and love letters, all of that.
• 36:22
  So that's how in 1951, Turing was established in Manchester, a very minor public figure.
• 36:28
  He was also elected fellow for our society in 1951, and it was for that 1936 work.
• 36:35
  Two characteristic stories, he said.
• 36:38
  I suppose they couldn't have made me an IFRS when I was 24, which is rather bragging, but on the other hand he wasn't really like that.
• 36:47
  A young research student, rather tactless. They said to him, Oh, I didn't think of using the phrase.
• 36:52
  And he is laughed at that he didn't mind. He is.
• 36:58
  He had this lower upper middle class accent, of course, and Cambridge done background, but he still rather had this air of graduate students.
• 37:06
  And he didn't have a side, as people said. He was very accessible to people on the right wavelength.
• 37:14
  That's a fully engineered mass. Just the computer was inaugurated in that same year, July 1951, and it was summer,
• 37:22
  and the organisation was nothing like what had been envisaged originally by Newman.
• 37:27
  It was dominated by the fact that government had supplied money for the atomic bomb calculation to be run on it, and that's what it was for.
• 37:35
  And Turing's role wasn't really terribly clear. But on the other hand, he had a lot of freedom in using it, especially at night.
• 37:42
  So it almost got a private or personal computer, whether only three or four in the world.
• 37:49
  Now, one can see and there he is at the at the console of the machine on the right there.
• 37:55
  Now, you can see all the things that he might have done that I didn't do, could have promoted Turing machines,
• 38:01
  theory of computation, started complexity theory, higher programming conferences, books, all sorts of things.
• 38:08
  Well, none of that happened. He didn't do that. The future, of course, really lies in software architecture rather than this hardware building.
• 38:17
  But it was Christopher Street who followed that line of thought into the future.
• 38:21
  Turing himself left it to others. So that brings the question now, having gone to this other state, what does he do with it?
• 38:30
  What do you do next? Well, I tell you one thing he did next.
• 38:34
  He went on running and he had a new running partner and around Cheshire Villages where he lived.
• 38:41
  This was the 17 year old Alan Garner, later famous as the author of the Owl Service and other iconic fiction.
• 38:48
  But at that stage in the Manchester Grammar School, sixth form schoolboy and that is a very curious fact which of our time we'll we will come back to.
• 39:00
  But he was also doing completely new work. And we have very little idea of what the precursor to this was.
• 39:06
  And it came out of the blue and it was this mathematical theory of biological growth and form based on reaction and diffusion and physical chemistry.
• 39:17
  It was certainly going strong and in February 1951, and it had some possible connection with his interest in the question of brain growth itself,
• 39:29
  an outcome of his interest in intelligence and learning processes.
• 39:32
  But I think it was much deeper than that. He went back to physical chemistry he he'd done at school or even even earlier.
• 39:39
  Anyway, it's classical applied maths.
• 39:42
  It's not a business of the discrete as like in networks, it's actually classical analogue and continuous mathematics.
• 39:52
  But the computer comes in crucially because the equations that he wrote down cannot be solved analytically,
• 39:58
  and the computer gave the prospect of pure scientific research that would never have been possible before.
• 40:04
  So his first paper, on the Chemical Basis of Morphogenesis, was submitted in November of that important year, 1951,
• 40:12
  and it has become one of the most cited in mathematical literature and a founding work in mathematical biology.
• 40:20
  But I'm going to skip a description of his theory,
• 40:22
  even though he had a delightful model for the processes of reaction and diffusion in an island of missionaries and cannibals.
• 40:31
  Very typical way to illustrate ideas.
• 40:35
  I'm going to go straight and quote something very important about the unpublished work that's here and did after finishing this paper.
• 40:42
  And this is by Professor Jonathan Dawes.
• 40:45
  Building on earlier work, especially that of Jonathan Swensen, who looks at the very difficult pile of manuscripts that Turing left.
• 40:54
  He's gone much further in piecing together some of the disordered pages.
• 40:58
  And one of his conclusions is that, well, I've posted here and it's essential.
• 41:03
  The point is that the work that Turing was doing throughout the two years, from 1952 to 54,
• 41:10
  where new ideas and applied mathematics that would have had substantial influence across the whole subject,
• 41:16
  they would have spurred the development of parts of the subject that otherwise took several decades to be realised.
• 41:22
  In particular, Turing arrives as an equation for a model that otherwise was only arrived at in 1977.
• 41:29
  His ideas are relevant not only to biology, but to nonlinear dynamics.
• 41:33
  For instance, in the novella Stokes Equations for Fluids.
• 41:37
  This was miles ahead, and the Manchester computer, of course, had none of the fast, visible graphic displays that we now enjoy.
• 41:45
  So this was the kind of graphic display he had. It was a printout in which he'd do his own coloured drawings based on the on the print.
• 41:54
  Doubt. I mean, you can just see from the picture that he he he should have been living at least 1984 or not 54.
• 42:03
  I mean, he was miles, miles ahead and other things in the 5354 period.
• 42:10
  There was work in a number theory and he showed himself really up with ideas in quantum mechanics and
• 42:16
  relativity and everything was going really well in that his university position was on a more solid footing.
• 42:23
  He had a small research group going.
• 42:25
  And so you could imagine him as being an absolute leading figure of the 1960s with the new universities, if he'd wanted to.
• 42:31
  I mean, that's the kind of position he was in. But on the morning of June the eighth, 1954, he was found dead in his bed.
• 42:40
  It was cyanide poisoning. The setting was a strange one of electroplating experiments in the next room and bedside slices.
• 42:48
  Apple cyanide organs are full of the cyanide.
• 42:51
  And he died the evening before. And it was assumed, I think, perfectly correctly, that he had eaten a poisoned apple.
• 43:00
  Now, why? And that gives the attention to this question.
• 43:05
  Of course, it's all connected with his being homosexual when all male same sex relations were illegal.
• 43:13
  He was arrested on the day. Well, it was the day George six died and he underwent a criminal trial on 31st of March, 1952.
• 43:24
  Well, I want to get some picture of his identity as a gay man.
• 43:27
  You have to go back because he's not an axiomatic system. You have to think he was a real person now.
• 43:32
  I mean, he's Alan now, I think to me. And he himself.
• 43:37
  Certainly.
• 43:38
  I mean, I want to draw a parallel with his scientific life in that he starts off immersed in very old fashioned class and privileged questions,
• 43:48
  becomes very modernised in such a way that as Michael introduced him to us this evening,
• 43:54
  how our legislation, our culture is now involves his story in quite an essential way.
• 44:00
  So let's go back and see what what he was like.
• 44:04
  What I'm going to give you a nice picture of what he was like at school is in 1919.
• 44:10
  These are pictures of 1931. You can see he was in a cell.
• 44:14
  He anticipated the selfie. You can certainly see that.
• 44:18
  And you can see that he would have had no problem with surfing the Internet at all if it survived.
• 44:24
  But the thing is, these are here to see his physical look.
• 44:29
  I mean, swimming, running, cycling, hiking, boating.
• 44:32
  These were his things. And this scruffy look that everyone moaned about all the time in the in the forties and fifties, this was him, too.
• 44:42
  He was just too early for the jeans and t shirt of the 1960s in which he would have been perfectly happy and acceptable.
• 44:50
  That was what he was like. And he retained all that outdoor and and this sort of physical look.
• 44:57
  That's what he was like. There's a well-known story that move on.
• 45:04
  Yeah, that was a well-known story that he was at school.
• 45:08
  He worshipped from a far slightly older boy called Christopher Walken.
• 45:13
  In fact,
• 45:14
  the nearest you got to friendship really was going on a group to Cambridge for the scholarship exams when they went together in December 1929.
• 45:24
  Christopher then died very suddenly after this, and it had a great impact on Alan Turing.
• 45:28
  Something which I must say he was very open about. This was something he discussed his feelings and his is the thoughts that it evoked.
• 45:36
  And in particular, it was actually much closer to another boy called Victor Beutel and helped him get over the crisis in 1932.
• 45:46
  Another important aspect of this was going to King's College. He was lucky that he got into his second choice college, if you like,
• 45:52
  because that was the liberal gay enclave with the main Arkansan, a number of other people.
• 45:59
  It was the liberal establishment.
• 46:01
  And he formed new friends there, one of them being David Champion down, who I mentioned, who remained a lifelong friend,
• 46:07
  a very understanding person and indeed a sexual relationship with one of the other math students, James Atkins.
• 46:13
  He had a lot of support for Summit in the 1930s. He really had a lot, but he was not at ease with himself at all.
• 46:22
  Usual things. Unrequited passion, loneliness.
• 46:25
  Why me? Why is this happened? All those thoughts, I think, very much depressed him in that period.
• 46:35
  One of those friends was the king's classicist, Fred Clayton, who has been in Germany in 1937,
• 46:43
  and they'd sponsored two Jewish boys who came as refugees in early 1939, and they helped them out.
• 46:51
  And there's a striking picture here in the last week of peace, the last week of August 1939,
• 46:57
  where they took them boating along the front and Fred at the back and the two boys in between.
• 47:04
  And I'm yeah. So and went off to war immediately after that and it would seem to me that actually
• 47:14
  that the elder of those two boys was probably the person most on his mind emotionally.
• 47:19
  I mean, purely emotionally. I mean, there's no no physical contact.
• 47:23
  And I think it may well be that this was he didn't.
• 47:27
  So this is not a good direction to be going in.
• 47:31
  And this is one reason why in spring 1941, he made a marriage proposal to Joan Clarke, who was on their right there.
• 47:40
  She was Gordon Welshman's fourth year and students at Newnham College and sister of the King's College Fellows at one of the of the group.
• 47:48
  She and she joined Alan Turing section on Naval Enigma.
• 47:53
  And in June 1940, I mean, she was a real kindred spirit and someone that Alan said he could talk to as a man, but she wasn't.
• 48:02
  And it was essentially doomed, especially as he started immediately on the engagement with a talk about his homosexual tendencies.
• 48:10
  Joan knew this was not really going to go somewhere.
• 48:13
  It ended in August 1941 in Wales when they had a week off and perhaps there was more opportunity for physical contact anyway.
• 48:22
  It was impossible to go on and Alan used a literary reference.
• 48:27
  When he called it off, he quoted Oscar Wilde for Each Man Kills the Thing He Loves and so on.
• 48:33
  It's from The Ballad of Reading Gaol. So yes, the service, his life.
• 48:38
  This is very a very difficult period. It was not something that we found very fulfilling.
• 48:43
  He became much more confidence in the later part of the war and in after the war.
• 48:48
  One reason seems to be he discovered, I think while in the United States on that liaison trip and then possibly in Paris
• 48:55
  when going to on the way to Germany to to to see the German communications equipment,
• 49:03
  the possibility of consular pickups. Anyway, back in King's College, Cambridge in 1948, he was much more confident.
• 49:11
  That was when he came out and made friends on a new level with Robin Gandhi,
• 49:16
  but also made new friends, one of whom became a longer term lover, Neville Johnson.
• 49:22
  His name was a boy from Newcastle. He was 24. Then after coming out of service they went cycling in France in 1948,
• 49:30
  just the kind of thing that had the best chance of setting, settling into a continuing relationship.
• 49:35
  But that was really bedevilled by their long distance problem, which affects so many people.
• 49:40
  Alan Turing move to Manchester and never had his job in reading and it was difficult to keep going.
• 49:46
  Meanwhile, in Manchester, temptation lurked because by the university there was this unique area, unique in the north of England anyway,
• 49:56
  of this sort of gay identified cruising block and Alan Turing could be seen there after 1950 or so.
• 50:04
  So that brings us to that fateful year in 1951.
• 50:07
  That was when he decided, after submitting his paper, that he had earned what he described as another gay man.
• 50:17
  It's interesting he used the word gay, which was then American usage.
• 50:22
  It wasn't really the British usage, but there it is in his writing.
• 50:26
  And he did. He met this young photo printer called Arnold Murray and took a shine to him.
• 50:31
  His chest up line was that he worked on the electronic brain and the electronic brain got everywhere.
• 50:38
  And unfortunately Alan Arnold was not a very suitable boy.
• 50:46
  And after some petty theft, Turing had to go to the police on the grounds that he was subject to an implicit kind of blackmail.
• 50:56
  He didn't handle it very well, and the police soon came to arrest him.
• 51:01
  In fact, both of them are charged in exactly the same way.
• 51:05
  Under the 1885, at the same one as Oscar Wilde had been prosecuted under the new conservative government,
• 51:14
  was leading quite a crack down at this point. And this was part of what was a very large scale thing that was happening.
• 51:21
  Public opinion was entirely in favour of the law as it was. There was virtually no opposition to it.
• 51:26
  So Turing's response to being charge when he said, I thought there was a royal commission sitting to legalise it, well, it certainly wasn't.
• 51:33
  But the thing is that hearing said what the liberal elite may have thought but kept to themselves, and that was his characteristic.
• 51:41
  It was very modern and in 1952 quite shocking, and it did him no good at all.
• 51:47
  It's well known now that what happened when he was convicted was that he was on probation,
• 51:55
  having to take these hormone injections actually for a year.
• 52:00
  And that's I suppose people think of that as being some very cruel thing that was devised at the time that would have been seen as the soft option.
• 52:07
  I mean, the fact was it was the modern, it was the scientific option.
• 52:12
  The irony of this, I'm sure everyone appreciates.
• 52:15
  But it did mean that he didn't lose his job as he would have done if he'd refused and gone to prison.
• 52:21
  And again, it's often thought that he declined thereafter and fell away and his mind was
• 52:28
  wrecked and originality left him by this dreadful assault of the biochemistry.
• 52:35
  But there's really no evidence at all.
• 52:36
  And that's why I emphasised in this earlier section that he was doing work of the greatest originality stuff that was decades ahead,
• 52:44
  and that continued right up to the end. In fact, it was the other way round.
• 52:49
  I mean, he really stood up to this and insisted on continuing work of the highest quality, and he stayed.
• 52:57
  His whole response to the crisis was very sophisticated. It had that same mixture of dead seriousness and humour, as in the scientific writing.
• 53:05
  I had a very agreeable feeling of irresponsibility, he said of the trial, rather like being back at school.
• 53:11
  And it's a very upper middle class thing to say for that, but slightly more modern existentialist way, he said.
• 53:19
  No doubt I shall emerge from as a different man, but quite who I have not found out.
• 53:25
  He made a quite decisive step in this existential question by consulting a union psychotherapist,
• 53:33
  Franz Greenbaum, who was another refugee, Jewish refugee from Nazi Germany.
• 53:38
  And he was reading in modern literature. And he did. He was writing, too, because he wrote a short story about his experience.
• 53:46
  Interestingly, quite avant garde in that he looked at how he himself would be seen by a working class young man.
• 53:54
  But the most positive thing of all was escape to Norway of all places.
• 53:59
  And that's sorry, that's the photograph at the bottom,
• 54:03
  which is from the Scandinavian very early Scandinavian gay rights movement of 1952 and was their magazine.
• 54:11
  And that was exactly what he wanted. I mean, that was the idea was was marvellous.
• 54:15
  And he switched over to Norway in the summer of 1952, despite being on this treatment and the rest of it and fact it,
• 54:25
  he was learning Danish and Norwegian with great enthusiasm.
• 54:29
  In Bergen, he met a young man called Kjell and you'll see Kjell theory and kill programs all over the morphogenesis work.
• 54:38
  And that's where it where it comes from. He didn't divide his life into into compartments very well.
• 54:44
  And indeed, he talks about all these events a great deal with people in the computing laboratory.
• 54:51
  Well, no, he lost Neville. Neville Johnson, the boyfriend from 48 to 1950 or so because Neville's mother forced him never to see Alan again.
• 55:01
  I mean, she was she had a point. I mean, he was dangerous to know about one person.
• 55:05
  He did become a lot closer. Was Nick Fairbank from King's College, Penn Fairbank you could have seen his name.
• 55:13
  He is the biographer of E.M. Forster and in fact, a critic with many articles in the Times, literary supplements and things like that.
• 55:19
  Until his recent death, actually the release of some papers.
• 55:24
  And Nick Fairbank gives a little bit more explanation for Turing's frame of mind, which I'd like to share with you.
• 55:30
  It's clear now that for a time in late 52 and in 53, Alan Turing seriously entertained the thought that he would become bisexual,
• 55:40
  like many people he knew were all least claim to be. I mean, anyway, Maynard Keynes comes to mind certainly was his thing.
• 55:48
  His view of the psychotherapy was that a heterosexual side of him could emerge
• 55:54
  from the subconscious is unblocked by young young in analysis of his dreams.
• 56:00
  Indeed, he told Nick about a dream, which he said proved that this was happening.
• 56:06
  It was unusual, I think, as a gay man, as he was never denying his gay side at all.
• 56:11
  He was always very positive and open about who he was attracted by and the excitement of encounters.
• 56:17
  But it seemed that he hoped that he could feel heterosexual attraction as well, not as some kind of cover story,
• 56:24
  but as really authentic and then settled down in marriage, I think very similar to what he'd hoped in 1941.
• 56:30
  And that's, I think, is to explain something that always. It's not hard to understand why on earth he chose Corfu for his summer 1953 holiday.
• 56:41
  He went to the club Mediterranee just started and is really the vanguard of the new leisure 1950s, sunny sort of Europe.
• 56:50
  I think he went there to see if in this liberated environment he could detect any new physical interest in him in the other sex in himself.
• 57:00
  In fact, he wrote to Nick before he went that he would be making love, the nationality and sex of the partner to be decided.
• 57:08
  Perhaps, perhaps not at all, though, as it was something permanent that he wanted and why he was there.
• 57:14
  This is a little vignette of Alan Turing in this so absolutely critical period as the postcard that he sent to the psychiatrist.
• 57:23
  And it says, I'm here at Corfu. It is tremendously hot and one wears bathing things all day.
• 57:29
  This is not the picture of the shattered person.
• 57:34
  There's someone who is actually living life as much as they can.
• 57:39
  However, I doubt very much that this came this idea of bisexuality came to anything.
• 57:45
  He returned with a long list of Greek and French names and addresses.
• 57:49
  It seems that he did find some partners and be astonishing if they were other than young men.
• 57:54
  Leopards don't change their spots very easily.
• 57:58
  And this was just, I think, a dream of a genuine, stable, married state that could emerge for him just as it had been in 1941.
• 58:08
  So I think that's an important element of his story.
• 58:11
  And we think about the relationship between the arrest and and the trial and his death two years later.
• 58:18
  There's a whole journey here. To treat him as a whole person means taking these things into account and not just having a
• 58:25
  very one dimensional picture of of a wound and damage and collapse that was fighting back.
• 58:32
  There was very considerable uncertainty about what to do.
• 58:35
  But then there was something else that had to be has to be taken into consideration as well.
• 58:41
  And that is his special status. When the police had arrested him, it was just a very ordinary arrest.
• 58:46
  They had no idea who he was, but he was someone special. He was the Anglo-American world's top crypto consultant.
• 58:54
  And he, of course, his friends had no idea of this whatsoever, and they had no idea what he'd done in the war.
• 59:01
  No one breathed a word about this until the 1970s.
• 59:05
  Additionally, since 1948, he'd done further work for GC HQ, which is of course abruptly stopped when he was arrested.
• 59:13
  He also had, if you remember, special United States clearance.
• 59:17
  So what in 1954 would have been extremely sensitive topic, speech, incitement at once.
• 59:24
  What happened was the boy from Norway, Kalle, came over and landed at Newcastle intending to visit him.
• 59:32
  But as Turing reported, half the police in the north of England seemed to be out looking for him and intercepted him and sent him back to Norway.
• 59:40
  The poor sweeties, he said, did not know there was nothing but a kiss with this young man in Norway.
• 59:46
  Well, the poor sweeties were not the local police.
• 59:49
  This is a national operation. And the reason is obvious.
• 59:53
  His activities with their potential for entrapment were real anxiety for national security.
• 59:59
  In 1954, it was clear policy to exclude homosexuals.
• 1:00:03
  Absolutely.
• 1:00:04
  From GHQ work and the current director of GHQ, Robert Hannigan, as recently confirmed that this was the case and remained the case until the 1990s.
• 1:00:14
  It's changed completely now. That was the point of his remark. This is in 1948 on their American influence,
• 1:00:21
  and it meant that during situation was nothing like what it had been in the Second World
• 1:00:25
  War when being a good chap from the right school and the right college was all you needed.
• 1:00:31
  GHQ could hardly have ignored their own security policy when a top scientific consultant very real,
• 1:00:38
  revealed as the very thing they wanted to exclude at all costs.
• 1:00:42
  And not just that. It wasn't just that he was gay. He was involved.
• 1:00:45
  The lowlife is stroppy, utterly unrepentant and set on foreign travel to escape British law.
• 1:00:52
  It's really surprising that he was allowed to go abroad in the summer of 1953 and probably had to fight for permission.
• 1:00:59
  In fact, there's a big page of hints that he wrote to Robin Gandy in joke, hints about being stopped from from leaving the country.
• 1:01:07
  But Robin didn't guess it. I think Turing's humour was sometimes too subtle.
• 1:01:12
  Anyway, it may be that it was after this period that I think he seriously considered the only existentialist way out of this, which is suicide.
• 1:01:24
  He in March 1953, he announced that he'd put together a chemistry laboratory in his house, mentioned that very offhand.
• 1:01:32
  But that had a real. Meaning it was the means of his death if he chose to take it.
• 1:01:37
  It always had this melodramatic thing about chemistry.
• 1:01:40
  It goes right back to his school days, even joking with Christopher Malcolm about absolutely deadly substances.
• 1:01:46
  He had a slightly melodramatic and slightly morbid interest in this in this whole thing.
• 1:01:53
  In fact, we can see even in 1936 when he was so successful and everything was going so well, his mother knew there was something really wrong.
• 1:02:02
  And it turns out that she wrote behind his back to the dean of the Graduate College in Princeton saying To wash out,
• 1:02:09
  there might be some unforeseen emergency and they should know how to contact the Turing family if such a thing happened.
• 1:02:16
  Clearly, she knew something, and this was classic interference, but she had a real point.
• 1:02:22
  In 1937, Alan Turing wrote to his King's College boyfriend, James Atkins, about having a suicide plan.
• 1:02:30
  Indeed, there was an event in 1937 could very well have triggered such thoughts.
• 1:02:35
  And the plan, as James recalled to me, involved an apple and electrical wiring.
• 1:02:40
  And the point of the plan is to have a plan at all was that it was to disguise suicide as an accident,
• 1:02:46
  as a chemical accident and accident doing a chemistry experiment.
• 1:02:50
  And it was for the sake of his mother. I mean. So other people can confirm some of this.
• 1:02:58
  And so he knew his mother well, and she did indeed fall for this.
• 1:03:02
  Exactly. And believed that he had transferred the cyanide by accident from the experiment to his apple and ate it by mistake.
• 1:03:11
  Getting the sun was easy. He got it from the Manchester Chemistry Department.
• 1:03:16
  Very telling is that after March 1953, the same point, he was pressing Nick Fairbank to be the executor of his will.
• 1:03:23
  This is a very special will and it is clear from his letters to Nick, which were written in French, it's a cushion, I think is a very sensitive thing,
• 1:03:32
  is using Nick's own interest in French literature,
• 1:03:36
  and it puts it as something that might be necessary since trouble might come again, and it puts it in that way.
• 1:03:44
  And Nick agreed that Will itself was was signed in February 1954, very careful, totally unconventional.
• 1:03:53
  He cut his lawyer brother completely and devises his estate between the five most supportive people in his life.
• 1:04:00
  Nick Robyn Neville, David Champion and his mother.
• 1:04:07
  Now we don't know what happens. Robert Hannigan's recent statement from GCA HQ says that they stood by him.
• 1:04:15
  And I'm sure that Hugh Alexander, his deputy in the war and then the scientific head of THQ after the war, did stick up for him very strongly.
• 1:04:25
  But from the point of view of security and Alan Turing would have seemed criminally irresponsible if not certifiably insane,
• 1:04:33
  it would be very hard, very hard for you, Alexander, to argue that he did not need to be protected from himself.
• 1:04:41
  The Cold War was at its height in 1954. Opposite number Robert Oppenheimer was effectively on trial.
• 1:04:48
  Turing's friends and contacts would give no cause for complacency.
• 1:04:53
  They included numerous communists, as well as atomic scientists.
• 1:04:57
  But the main thing was he knew what hardly anyone in the world knew.
• 1:05:00
  This very nature of Anglo-American communication, crypto and security as the biggest secret of the lot in the circumstances.
• 1:05:09
  The amazing thing is not that he went, but that he lasted so long.
• 1:05:13
  He was a man who tried to be honest and truthful, which is what Newman said for him at the trial.
• 1:05:19
  But he was cursed with two things which went in the opposite direction and made everything a lie.
• 1:05:24
  The secrecy of the war work and the criminalisation of his sexuality,
• 1:05:28
  the combination of them both in the security issue, was clearly absolutely toxic.
• 1:05:33
  It's hardly surprising that he was crushed. Well,
• 1:05:37
  I think I'll have to leave this story at this point and invite you to see that and other ramifications and extraordinary episodes which feed into
• 1:05:47
  this and very interesting people and whole world of life and history which which is part of the human story and feed into this great web of science,
• 1:06:00
  which I referred to at the beginning, is a web in which he himself believed an individual only contributes a little bit.
• 1:06:09
  It is essentially a communal operation, and that's something where he ceased.
• 1:06:14
  But what he did lives on. Secondly, I should have done this at the beginning that I should thank Oxford Asset Management.
• 1:06:31
  Oxford Asset Management are our sponsors for these events. We couldn't.
• 1:06:34
  It isn't free to get a venue like this. They they do cost and we couldn't do an event on this scale and complexity without their support.
• 1:06:42
  So we're tremendously grateful to them. You can find out more about Oxford Asset Management over there.
• 1:06:47
  You can find out more about the department and what we do over here.
• 1:06:50
  And finally, just a reminder, if you'd like to pick up a copy of the book and Andrew indicated he'd be happy to sign copies,
• 1:06:56
  you're very, very welcome to over that. But one more time.
• 1:07:00
  Andrew, I've been waiting 31 years to hear you give this lecture.
• 1:07:03
  You didn't disappoint. That was a fantastic straight G lecture. Thank you so much.