For Alan

Alan Turing was one of the greatest mathematicians of all time. In that remarkable period between the two world wars, it was as though people knew that the technology to actually build the long dreamed of machines that could think, at least in terms of computing, solving problems and proving theorems was almost available. The greatest minds bent to the task of determining just what was possible for such machines to achieve. Bertrand Russell and Alfred North Whitehead tried to develop the whole of mathematics in an automatic, rule-based way and failed. Kurt Gödel conclusively demonstrated that there would always be things that were true but could not be proved in this way. Turing developed a theoretical machine that bears his name. Very simple, and with sequences of operations, or programs, He showed that anything that was theoretically computable, could be represented by a Turing Machine with a suitable program. He went further and imagined a Universal Turing Machine, which with a suitable input could emulate any other Turing Machine. This result remains the basis on which all modern, stored program, digital computers work. He was also interested in Artificial Intelligence and developed the Turing Test, to determine whether a machine could be deemed to be intelligent. Variants of this test still remain the standard for this field of study.
He is perhaps best known for breaking the “Enigma Code” at Bletchley Park during the Second World War. In fact his major achievement there was to build a machine that enabled signals to be encoded fast enough for the information they contained to be relevant and useful. He is credited with shortening the war by several years and saving thousands of lives.
After the war he returned to academia to start building the first true digital computers. His wartime work remained secret and his homosexuality made him a security risk, so there is some doubt as to how big a part coercion by intelligence agencies played in his fate. Male homosexuality was a criminal offence at the time, and he was brought to the attention of the police and prosecuted. He was given the choice between prison, a horrific experience for a gay man at the time, or undergoing a process known as “chemical castration”. He was made to undertake a course of treatment with a powerful cocktail of drugs and hormones, all with known physical and mental side effects. While the balance of his mind was thus greatly disturbed he took his own life by painting the outside of an apple with poison and taking a bite.

You dream’t the machines that ruled our world,
set the limits of what they could do.
devised a test to see how far they’d got
along the path that you mapped out.

Dragged from your ivory tower and put to work,
you won their war, saved many lives,
helped build the machines to run
the brave new world you saw for us.

Where would we be now if you had lived.
What wondrous machines could you have made.
Would they pass your test and, head held high,
walk our city streets alongside us.

And would they laugh like us, love like us,
wonder about the universe as we do.
Would we and they together finally solve
that hardest problem of how we feel.

But we must do it alone, without you.
You loved, but not the way they liked.
They reached up from their gutter, dragged you down,
destroyed your sanity, made you take
the fatal bite.