On Alan Turing – without whom your computer might not exist

Posted by on June 23, 2012

If it wasn’t for the British mathematician Alan Turing, who was born 100 years ago today, you probably wouldn’t be reading the Macmillan blog – or any other blog for that matter. Without Turing’s visionary thinking, computers may not have developed as far as they have.

A website dedicated to his work describes Turing as the ‘founder of computer science’, and this is no exaggeration.

In 1950, Turing wrote a paper which began with the words: ‘I propose to consider the question, “Can machines think?”’ He quickly redefines this question, so that it becomes something like: can a computer, in answering questions put by a human inquirer, give a sufficiently convincing imitation of human thought to make the questioner unsure whether the answers are coming from the computer or from another human. The computer, in other words, has to play what Turing refers to as ‘the imitation game’ – and play it well in order to pass what we now call ‘the Turing test’.

Turing was well aware that the computers which existed in 1950 (and there weren’t many) were not capable of passing his test: ‘We are not asking’, he says ‘whether the computers at present available would do well, but whether there are imaginable computers which would do well’. He then goes on to raise, and demolish, a series of possible arguments against the idea of machines being able to think. It is a wonderfully clear demonstration of his confidence in the future of computing, and his paper is generally seen as laying the foundations for artificial intelligence.

As far back as 1936, Turing had speculated about how machines might be able to perform complex mathematical tasks. The hypothetical device he described – now referred to as a Turing machine – was a kind of prototype for the modern computer. Turing was just 24 years old, and at that time the word ‘computer’ (which dates back to the 17th century) still referred to a person (someone whose job is to perform calculations) rather than to a machine.

During World War 2, Turing was a key member of the code-breaking team based at Bletchley Park. Their task was to decipher enemy communications, which were encoded using an ‘Enigma’ machine – a technically advanced device which enabled its users to change the code settings on a daily basis. The eventual success of Turing and his British and Polish colleagues meant that the British and Americans could read secret German military intelligence, and this made a critical contribution to the Allied victory.

Turing’s life ended tragically. In 1952, he was convicted of ‘gross indecency’ – in reality, he was put on trial simply for being gay, which was illegal in the UK at that time. Two years later, he committed suicide. In a moving tribute written in 2009, British prime minister Gordon Brown issued an official apology for the way Turing had been treated. Brown’s article focussed on Turing’s contribution to the ending of World War 2, but in the long run, he will surely be remembered most for his clear-sighted predictions of the possibilities of computing and artificial intelligence.

His groundbreaking 1950 paper ends with the words:  ‘We can only see a short distance ahead, but we can see plenty there that needs to be done’. Turing saw further ahead than most of us, and if he were alive today he would probably not be all that surprised by the way intelligent machines have developed.

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Comments (1)
  • Thanks for a great post, Michael. I’ve been fascinated by Turing ever since I read a great bio of him (called “Enigma,” I think) many years ago. He left a huge legacy that’s all the more remarkable for his dying so young.

    Posted by Orin Hargraves on 23rd June, 2012
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