Interview with Andrew Hodges. Part 1.

Earlier this year I was lucky enough to have the chance of interviewing Andrew Hodges about his experience of writing a biography of Alan Turing, "Alan Turing: The Enigma". Since we spoke for quite a while I've decided to serialise the interview over the next few weeks. This week I introduce Andrew and ask what set him on his path of writing the book.

If you are interested in reading more about Andrew Hodges you can find his website here and his book can be bought from here.

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Firstly, for those who do not know of your career, could you just give an outline of how you came to where you are?

I am in an unusual situation, because the Turing material is something that took me off from my normal trajectory. It was not a direct part of my normal progress as I was already a post doctoral researcher in quite a different field, mathematical physics; working with Roger Penrose. Although I took time off to do it I managed to mix it in with my research over the six years, from 1977 to 1983

In 1985 I received an advanced Science and Engineering Research Council fellowship, which really established me in Oxford, where I have been ever since.

You did your Phd in 1975 in twistor theory and continue to work in this area to this day. Can you explain a little about what this is? It is linked to string theory isn’t it?

It is really very different from string theory, although there is more overlap now.

String theory is about adding in extra dimensions to space and time and structures within those. Twister theory is simply a different way of describing the four dimensions that we know about. So in that way it is less radical!

What do you get out this description that the normal view of space and time doesn’t give you?

Instead of thinking about the four dimensions as physical description of three space dimensions and one dimension of time we instead think about of two dimensions plus two dimensions. It is based on a set of light rays which are the fundamental objects.

This description fits very nicely with the way the whole of fundamental physics has gone which puts emphasis on objects that have zero mass. The ideas behind the Higgs field and gluons also fit beautifully into this point of view.

Since you work in such a different field to Turing how did you first hear about him

In 1969 I was a Cambridge undergraduate and at that time his name wasn’t well known to most undergraduates. I read a lot of maths that was not on the syllabus and I discovered his work on Turing machines. So his name at least meant something to me at that time and I was very surprised during 1972-73 when his name came up in quite a different way. I met many people in the Gay Liberation movement who had actually known him.

So Alan was more famous in the gay community than the mathematical one?

Oh no. He was by no means a household name. It was simply coincidence of meeting the older generations and having seen his name before. Very few people knew of this connection to Turing. Of course, it is well known now, but at the time it was something no one wanted to talk about.

The third connection was that in the mid 70s, books started leaking the details of the work done in Bletchley Park. Also the BBC had a very good programme on how the Enigma was broken but it didn’t really highlight Turing’s role. It mentioned that he was there but didn’t discuss his work, whereas through my connections I gathered that he wasn’t just “there” but actually he was the most important figure in the whole project.

And is that true? Turing is often praised as being the genius behind the breaking of Enigma but there were plenty of others there working with him who should also not be forgotten.

I don’t think any of the other big people (Donald Michie, Max Newman, Jack Good and Shaun Wylie to name but a few) would have questioned his importance… on the scientific side of course. There were many important people running the infrastructure, engineering of the machines and linguists, but on the scientific side there is no question of his influence. He was both the first serious scientific person into the field of decryption and the most innovative.

He had a very unobvious idea of how the Enigma machine worked and also developed all of the statistical theory which they used.