LGBT+ History Month - Alan Turing

Despite having a relatively short life of only 41 years, Alan Turing is one of the most consequential people of the twentieth century, by helping to crack Nazi secret codes, shortening the Second World War as a result, and conceiving the modern computer as a universal computing machine capable of processing any problem that is humanly computable.

A mathematician, a logician, a scientist; his remarkable life shows the power of a genius to change the world.

Born in 1912 in Maida Vale, London, his teachers soon recognised the insight of his intellect at a young age, and this was matched by his dedication as a student.  His first day at Sherborne School in 1926 happened to coincide with the general strike but undeterred, so a well-known anecdote has it, he rode his bicycle all the way from Southampton to Sherborne in Dorset (sixty miles in all) by himself to be able to attend, staying overnight at an inn.

It was at Sherborne School that he made a dear friend of around the same age, a boy named Christopher Morcom.  Alan was fond of Christopher, but his friend sadly died from an illness at the age of eighteen, causing him to grieve deeply.

After leaving school, Alan pursued mathematical studies and this led to him working on problems concerning algorithms and computation. In 1936, years before the creation of the first electronic computers, he wrote a paper showing that a “universal computing machine” would be capable of performing any humanly conceivable mathematical computation representable by an algorithm. It was this paper that laid the theoretical groundwork for the modern computer, and it has been called “easily the most influential math paper in history”.

In 1938, Alan joined the Government Code and Cypher School, and at the outbreak of the Second World War, he moved to their wartime headquarters at Bletchley Park in Buckinghamshire.  At the park, electromechanical machines called bombes were developed to decipher the secret codes devised by the Nazis’ Enigma machine and he was a leader in their efforts to halt the enemy war effort by understanding their encrypted messages. The bombes were not computers, but a striking aspect of their use was the use of a machine to process information in a way that would otherwise have to be undertaken by people, in a similar way to how computers are used now.

At Bletchley Park, to help cope with the stress of his work, Alan exercised regularly by running long distances, including to London when he needed to attend meetings there. He proposed marriage to a colleague of his at the park named Joan Clarke, but the engagement was short-lived when Alan told her that he was gay, and he decided that he could not go through with the marriage.

Successes in code-cracking soon saw a reduction in losses of allied shipping from enemy attack, but their limited funding and resources frustrated further work. Alan wrote directly to the Prime Minister, Winston Churchill, who, upon realising the importance of their work, immediately wrote a memo with the words “ACTION THIS DAY” on it, demanding that the Bletchley Park team be given all they needed.  Being able to read secret Nazi messages during the war was useful to the allied war effort, and his work significantly contributed to shortening the war and saving lives. In 1946, he was appointed an Officer of the Order of the British Empire (OBE) by King George VI for his wartime service.

After the war, Alan became involved in the design of the new electronic computers and proposed the Automatic Computing Engine (ACE), the first detailed design of a stored program computer. If built, it would have been faster and had more memory than other computers of the time, but his engineering colleagues thought it was too difficult to attempt at the time, and a much smaller machine was built, the Pilot Model ACE in 1950. He also wrote the first-ever programming manual and in 1951 his programming system was used in the Ferranti Mark I, the world’s first commercially available general purpose computer. This shows how his genius was not just for the theoretical, but also for cutting edge practical implementation of the time.  He also co-wrote one of the earliest computer games, a chess program later called Turbochamp, although it was too complex for the computers of the time.

Later he developed theories concerning artificial intelligence (AI) which have provided the framework for the development of this field of study ever since.  He created the well-known “Turing Test” in 1950, a test to determine whether a machine could have human-like intelligence, involving a text-only conversation in which a human judge chats with both a human and a machine. If the judge cannot reliably tell which is which, the machine “passes.”  Interestingly, this is no longer the gold standard test for AI, especially given that in most situations, a modern AI system can pass the Turing Test, at least in short conversations.

At the start of the 1950s, Alan became interested in biology and artificial life, and how form and pattern developed in living organisms.  He used the Ferranti Mark 1 computer in modelling his hypothesis concerning the generation of structure in animals and plants.

Around the same time, he began a relationship with a man and through a series of events this led to his conviction for gross indecency under section 11 of the Criminal Law Amendment Act 1885 as homosexual acts at the time could be a criminal offence.  Following his conviction, he chose to have probation, and this was subject to his agreement to undergo hormone treatment referred to as “chemical castration” to reduce his libido.   

His extraordinary life was cut short by his untimely death in 1954.  His housekeeper discovered Alan’s dead body and a post mortem held later the same day determined that he had died the day before from cyanide poisoning. The subsequent inquest ruled that his death was suicide, but this has long been questioned.  In the period prior to his death, Alan gave no indication that he was suicidal, and the chemical treatment he had undergone had stopped over a year prior to his death.  We may never know for sure, but it is possible that the cyanide in his system came from scientific experiments he was carrying out in his spare room, and that his death was a tragic accident rather than suicide.

In 2009, Prime Minister Gordon Brown released a statement apologising on behalf of the government for Turing’s conviction and treatment. In 2014, Her Majesty Queen Elizabeth II pardoned Turing under the royal prerogative of mercy, only the fourth royal pardon since the Second World War.  “Alan Turing’s law” was enacted under the Policing and Crime Act 2017, which retroactively pardoned men who had been cautioned or convicted under historical legislation that outlawed homosexual acts.

Alan Turing’s legacy is immense and historic.  His work at Bletchley Park saved lives and shortened the war. It has been said his contributions were vital to the Allied victory. He envisioned the modern concept of a computer as a universal information-processing machine, machines on which our economy and culture, indeed our whole society, are now based.  The Alan Turing memorial in Sackville Gardens in Manchester is in memory of him, both as a hero of computing and as a gay icon.