The Turing Test, which determines whether a machine can “think,” is as important in today's world of rapidly expanding AI as it was when it was first outlined in the 1950s.
Its 75th anniversary is a great time to reflect on Alan Turing as a mathematician, computer scientist, and LGBTQIA+ icon. It is also an opportunity to celebrate those who continue his legacy.
Turing machines in the 1930s
Mathematicians in the early 20th century had the lofty ambition of making all mathematics computable. Ideally, we could build a machine that could, given any mathematical statement, decide whether it is true or false.
Their plans were upended in the 1930s when Kurt Gödel showed that there were mathematical statements that could never be logically proven or disproved. Shortly after, Alan Turing showed that computation has fundamental, insurmountable limits.
Turing's methods still permeate mathematics and computer science today.
Essentially, he described an ingenious abstract model of a computer, a machine that could read and write information to a tape (memory) and move back and forth along the tape depending on what it read.
He then advanced the simple and ingenious argument that if such a machine could decide whether or not another process could be terminated, we could create a logical paradox by asking the machine to perform its own analysis.
The fact that Turing conducted this research in the 1930s, before computers existed, is noteworthy.
props from imitation game At Bletchley Park. This film is based on the biography of Alan Turing.
(Photo credit: lenscap50/Adobe Stock)
break wartime norms
Some of Turing's most famous achievements were in cryptanalysis, the mathematical technique of breaking codes. He was the central figure in cracking Enigma, the German code machine used (and frequently upgraded) before and during World War II.
The 20th century saw cryptographers use machines in earnest for the first time to encrypt messages using constantly changing ciphers with vast numbers of cryptographic keys, rendering linguistic and statistical codebreaking techniques useless.
Mathematicians rose to the challenge of machines. As the war raged on, Turing became central to the development of the cryptographic “bomb,” a mechanical device that used logical reasoning to identify potential cryptographic keys.
These extraordinary machines provided vital intelligence to the Allies in the fight against German U-boats in the Atlantic, and undoubtedly shortened the war considerably.
thinking machine problem
After the war, Turing turned his attention to what is now known as artificial intelligence.
In a pioneering essay published in 1950, he asked, “Can machines think?” He took the approach of not debating what it meant to think, but rather explaining clear ways to measure it.
He called this the “Imitation Game,” and it is now known as the Turing Test. Using only text-based conversations, a machine passes the test if a human examiner cannot distinguish between the machine and the human.
Turing claimed that a machine could probably pass the test within 50 years and gave some concrete ideas on how to build such a machine.
Today, we often struggle to determine what content is produced by humans and AI, but Turing's prediction certainly appears to have come true.
His essay is still a very interesting read 75 years later, given what we know now, and still provides important food for thought.
Alan Turing's 50 pound note.
(Photo credit: Abdul/Adobe Stock)
Beacons for increased visibility
For me personally, Alan Turing's legacy lies not only in his mathematics (which can be seen in much of my own work), but also in his visibility as an LGBTQIA+ mathematician.
In the 1950s, when homosexuality was illegal in Britain, he was found guilty of “gross indecency”, stripped of security checks and given a choice between prison or chemical castration, or lethal injection.
He died at the age of 41 from cyanide poisoning, the reasons for which are still subject to speculation today.
In the 21st century, he was pardoned by Queen Elizabeth II in 2013, and in 2017 the broader Alan Turing Act was enacted, automatically pardoning people with similar convictions. Turing is now featured on the UK's 50 pound note.
LGBTQIA+ scientists are more visible than ever.
Events honoring Alan Turing and the 75th anniversary of the Turing Test at UQ will also celebrate LGBTQIA+ researchers in science, technology, engineering and mathematics (STEM), as well as a professional world conference in geometry and topology.
Alan Turing has given us a great legacy.
