Issue #6 - Alan Turing

Welcome to the 6th issue of Heroes of Computer Science! This one is going to be a bit longer, there is much to talk about… The timing is also essential, since the UK just released a bank note featuring this computer pioneer and codebreaker. 💷

Alan Turing

Widely considered to be the father of theoretical computer science and artificial intelligence, Alan Turing was an English mathematician and computer scientist. There are so many things named after him that this issue will only focus on a few highlights!

Perhaps his biggest contribution to the world was the series of improvements and breakthroughs during World War II, working for the British Government. Thanks to some inside information given to the Allies by Poland, Turing lead a team in developing and building devices that were able to break Enigma code in a more efficient way and even tackled more complicated cyphers. It is estimated by some that his work shortened the war in Europe by more than two years, estimating it to have saved over 14 million lives.

In 1936 he proposed the idea of a Turing machine, originally called an “a-machine” (automatic machine). Not a physical machine though, but rather an abstract machine, a mathematical model of computation that can read & write data, while following instructions. Related to it is the concept of Turing completeness, in which a system of instructions is able to simulate a Turing machine.

Also interested in Artificial Intelligence, in 1950 he described the Turing test, originally called the imitation game. While pondering if machines could think and realising that “thinking” is hard to define, he raises the question if an individual could identify answers written by humans or machines. You have a person A that can only communicate through text, sending questions to possible person B and possible person C — they can’t see each other. Based on the answers B and C send back to A, can that person identify who is the real person and who is the machine? If the answer is no, the machine was successful at exhibit intelligent behaviour, equivalent or indistinguishable from a human.

As a sidenote, since running plays an important role in my life, Turing was also a talented long-distance runner. On occasions, he ran the 40 miles (64 km) from Bletchley Park (where he was working for the government) to London when he was required for meetings. His marathon distance times were also world-class.

Lastly, Turing was a gay man at a time when homosexual acts were criminal offences in the United Kingdom. He was charged in 1952 of “gross indecency” and was given the choice between imprisonment or probation on the condition to undergo hormonal physical changes (designed to reduce libido), which he chose the latter. In 1954, Turing's housekeeper found him dead at the age of 41. Cyanide poisoning was ruled as the cause of death and it was determined as suicide, although some people believe it was accidental. The treatment administered to Turing was appalling and in 2009 the current Prime Minister acknowledged a petition that gathered more than 30,000 signatures, apologising on behalf of the British government. A second petition in 2011 received over 37,000 signatures and started a long exoneration process that culminated at the end of 2013, with the Queen Elizabeth II signing a pardon for Turing's conviction. In 2016, the government announced its intention to expand this exoneration retroactively. This is now informally known as the Alan Turing Law, an amnesty to posteriorly pardon men who were cautioned or convicted under historical legislation that outlawed homosexual acts.

Further reading

There are many books written about Turing, but Alan Turing: The Enigma is a well known biography and it’s also the book that inspired the movie The Imitation Game.

Another London landmark you’ll be able to find, if you’re ever around, is a blue plaque signalling where he was born.

During World War II, the English mathematical genius Alan Turing tries to crack the German Enigma code with help from fellow mathematicians.