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December 16, 2014

Turing’s Legacy

Posted by Tom Leinster

You’ve probably heard about The Imitation Game, a film about Alan Turing’s life starring Benedict Cumberbatch. Maybe you’ve seen it.

On Sunday, the Edinburgh Filmhouse hosted a special event, “The Maths Behind The Imitation Game”, organized by Edinburgh undergraduates and the department’s Mathematics Engagement Officer, Julia Collins. To my surprise, it was packed out, with a hundred or so people in the audience, and more queuing for returns. Someone did a great job on publicity.

The event consisted of three talks, followed by Q&A. I gave one of them. Later, Julia wrote a blog post on each talk — these are nicely-written, and say much more than I’m going to say here.

  • John Longley from Informatics spoke on computability and abstract notions of computation. Julia’s write-up is here.

  • I spoke on the legacy of Turing’s code-breaking work at Bletchley Park, comparing and contrasting things then and now. The notes for my talk are here, and Julia’s post on it is here.

  • Jamie Davies, an expert on the formation of tissues in mammals, spoke on the aspect of Turing’s work that’s perhaps least familiar to pure mathematicians: pattern formation and morphogenesis. For instance, you once consisted of just a single pair of cells. How did something so simple know how to develop into something as complex as you? Julia’s post is here.

Posted at December 16, 2014 6:02 PM UTC

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Re: Turing’s Legacy

Excellent talk. You do a good job of organizing the relevant facts: 1) the intelligence agencies undoubtedly have been able to gain, and are still trying to secure more of, the power to read and understand secret communications at will; and 2) that they have used this power in the past to persecute those who may be on the wrong side of the law but on the right side of an ethical issue.

I’ve been reading up on the Church Committee. The history raises some big philosophical questions. Do you think that there are some powers of government that should be completely illegal, due to chances of their misuse? In this case there is the power to intercept a communication with the hope of reading it (or just enough metadata to draw conclusions)–should that be completely forbidden, or should it be allowed, for instance, to fight Nazis but nothing less? Is there any hope of keeping the power available to fight evil while keeping it in check via lots of careful oversight and appeals? Of course this applies to lots of other issues, from nuclear weapons to drones to armed police–and might never have a completely satisfactory answer. Is there value in asking?

Posted by: stefan on December 16, 2014 7:50 PM | Permalink | Reply to this

Re: Turing’s Legacy

Great lecture!

The movie does not seem that great (I haven’t seen it yet). Scott Aaronson has a long list of inaccuracies. The guardian is very critical about the suggestion that Turing would be corruptable. What was your impression?

Posted by: Bas Spitters on December 17, 2014 8:48 AM | Permalink | Reply to this

Re: Turing’s Legacy


The film was kind of what I expected. For a mathematician, there are various obvious stupidities that make it hard to take seriously. For instance (spoiler follows), the climax of the film is when Turing realizes in a flash of inspiration that most German messages will include stock phrases such as “Heil Hitler”. I find that impossible to believe. As Scott says, that must have been obvious to everyone from the start; it’s only one step behind noticing that “e” occurs more often than “x”.

But as that Guardian article says, the really outrageous thing is the portrayal of Turing as knowing and keeping secret the identity of a Soviet spy. According to the Guardian article, this is an absolute fabrication. Not a shred of historical evidence supports it, or even the hypothesis that Turing and the spy ever met. Indeed, says the article, there’s evidence that they didn’t meet.

I hear that Andrew Hodges, the author of the 1983 biography on which the film is very loosely based, has refused to take part in publicity for the film on account of its inaccuracies.

Did I enjoy it? Kind of. I thought it was well-acted, if turned up to 11. I especially enjoyed Keira Knightley saying “oh” in a 1940s posh-ish English accent. It has about three syllables.

But I was watching the film in order to give this talk, and therefore taking notes (in a dark cinema — which is hard), so I didn’t really form an opinion on how entertaining it is.

Posted by: Tom Leinster on December 17, 2014 6:28 PM | Permalink | Reply to this

Re: Turing’s Legacy

There’s a very thorough dismantling at the New York Review of Books.

Posted by: Tom Leinster on December 21, 2014 1:56 AM | Permalink | Reply to this

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