Bronze-level article

Alan Turing

From RationalWiki
Jump to navigation Jump to search
Alan Turing
We need the best
Icon Tech Portal.svg
Programming for Dummies
Part of a
convergent series on

Here's this person, who is being murdered for who he is, after being one of the heroes for liberating people who were being murdered for being who they were.
—Jaron Lanier[1]

Alan Turing (23 June 1912–7 June 1954) was a [note 1] British mathematician, academic and a key figure in the Bletchley Park SIGINT operation during World War II (1939-1945), particularly for his work in breaking the Enigma code. He was a marathon runner of near-Olympic standard. He was (as it happens) gay, and a victim of state-sanctioned homophobia under a British law which criminalised homosexuality.

In 1952 Turing chose chemical castration as an alternative to prison after conviction for homosexual offences.[note 2] He died in 1954, after (as many think) choosing the Snow White route by eating an apple spiked with cyanide,[note 3] and therefore never lived to see the eventual revelation of his pivotal role in the Allied war effort, not to mention his lionization as the alpha hacker of all alpha hackers.[note 4][note 5]

It seems unlikely that the conviction as a common criminal of one of the most significant figures in World War II[note 6] had any influence on the liberalisation of British law on homosexuality in 1968: the Wolfenden ReportWikipedia of 1957 does not mention his case, and his wartime activity remained secret at that time.

In 2013 a royal pardon reversed his conviction - a belated apology for the injustices he had suffered.

Church-Turing thesis[edit]

Turing is regarded as one of the fathers of computer science for his co-development, with Alonzo Church, of the Church-Turing thesis, which hypothesized that any problem that is "effectively computable" (that is, solvable by mechanical means) can be solved using a certain sort of formally specified machine, which is now called a Turing machine.

He also devised a "universal Turing machine" that could "compute any function that any Turing machine can compute," which was a "blueprint" for the later general-purpose computers. According to the Stanford Encyclopedia of Philosophy, many philosophers of science, being unacquainted with the finer points of the theory, have grossly misinterpreted the thesis, falsely stating that it proves Turing machines to be capable of computing all that is computable, or that any possible computer architecture is no more powerful than the Turing machine.[2]

Turing Test[edit]

The Turing Test is a well known method for ascertaining computer "intelligence." It consists of a person (judge) communicating with two subjects, one of which is human and the other a computer. If the judge is unable to distinguish between human and machine then the computer is said to display intelligence. The communication is nowadays via typed words on a screen in order to remove other sensory clues. Turing originally conceived the idea from a variant of a sex detection parlour game and envisaged teletype as the communication medium. The Chinese room thought experiment attempts to refute the Turing test's standard for judging artificial intelligence.

A fundamental issue with the test is that it aims to trick human judgment, so that human judgment with all of its imperfections is the basis for passing the test. This means that trickery analogous to that of a stage magician can be all which is needed for a computer to pass as "intelligent". Such trickery could even matter more than actual intelligence on the part of the computer — and conversely, a genuinely intelligent computer with poor human-communication or acting skills would fail the test.

A comparison of Turing Test results of various subjects, including humans, two ChatGPT versions and ELIZAWikipedia (a 1960s era computer program that attempted to imitate a Rogerian psychologistWikipedia) found that among the four, ChatGPT 3.5 fared worst overall (5-14% pass rates), ELIZA (27%), ChatGPT 4 (6-41%), and worryingly actual humans at only at 63%.[3][4]

The imitation game[edit]

The original formulation of the test was known as "The Imitation Game", where person A attempted to impersonate person B. It was then up to the interviewer (Person C, if you will) to decide who was telling the truth and who was lying. Possibly due to Turing's interest in the nature of gender, he usually described A and B as a man and woman couple, with one pretending to be the other gender. The interviewer could ask questions and A and B, who were isolated from the interviewer so that even their voices wouldn't be heard, would then answer. The basis of the imitation game with regards to the development of the Turing Test was the question of what would happen when one of these individuals, A or B, was replaced by a machine (a computer, in our more modern views on how the test can be carried out). Unfortunately, this was a bit too much of a gender-bender for people's squeamish sensibilities, and almost every subsequent version of the test conducted left this part out, leaving it as just an interviewer and a simulated interviewee.[note 7]

Extra points[edit]

Extra points can be earned by either computer or human if they are able to convince the judge that he/she (the judge) is a computer.[note 8]Do You Believe That?

Other issues[edit]

If you asked any human: "What is 3690723?", the answer would be "I don't know". Therefore, any machine that could instantly answer questions which only a computer could instantly answer would reveal itself as nonhuman by answering the question, which could allow itself to be discriminated against. A computer which wished to pass the Turing test would have to feign ignorance, in other words, to try to pretend to be inferior to its true self. This means that pretending to be ignorant is a sign of intelligence, and that a machine which picks which question it should avoid answering is smarter than a machine that does not.


Turing was later convicted of having a sexual relationship with another man in 1952 and was given a choice between jail time and chemical castration through the hormone estrogen, and chose the latter.[5][note 9] His security clearance was revoked, leaving him unable to continue his work in cryptanalysis. He died two years later of cyanide poisoning, which was ruled to have been a suicide after an investigation, though his mother thought the death might have been accidental. A half eaten apple was found near him, and is speculated to be the means with which he ingested the cyanide, though the apple itself was never tested.[6]

In 2009, the British government apologised for thus driving one of the most brilliant scientists of the 20th century to his death.

Overturning of conviction[edit]

In December 2013, Turing was finally issued a posthumous Royal pardon.[7][8] As to the hundreds of other gay men? Not a word.

Criticisms against the legislation[note 10] ranged from poor education of law ("Oh, you're rewriting history!"), ad hominem ("This is why I can't take left-wing arguments seriously!") to outright homophobia ("There were rumours that Turing was a child molester!"[note 11]). Other, more sensible criticism has been raised by Glyn Hughes – sculptor of the Alan Turing Memorial in Manchester – who said he was "not entirely comfortable" that Turing had been pardoned while thousands of other gay men had not, saying that: "The problem is, of course, if there was a general pardon for men who had been prosecuted for homosexuality, many of them are still alive and they could get compensation."[8]

The Policing and Crime Act 2017 was given royal assent on 31 January 2017. This act implements, among other things, the 'Alan Turing Law' which gives an automatic pardon to men convicted for homosexual acts that are no longer considered illegal today.


In film[edit]

The 2014 movie about Turing's life, starring Benedict "One Computer Nerd Wasn't Enough For Me" Cumberbatch, was nominated for four Oscars (including Best Pic) and won one, for writer Graham Moore. It was called The Imitation Game (see above). Suffice to say, its multiple gross inaccuracies would not fool a judge.

Turing and Apple Computer[edit]

There is an urban legend to the effect that Apple Inc.'s bitten-apple logo is a homage to Alan Turing's manner of death. This lovely story is sadly untrue, although still very prevalent.[note 12][9][note 13]


The TuringWikipedia graphics processing unit microarchitecture by American electronics firm NvidiaWikipedia – which powered the RTX 20xx and the entry-level GTX 16xx graphics cards – was named in honour of Alan Turing.[10]

See also[edit]

External links[edit]


  1. What was he? He was a goddamn hero, and why we're not all speaking German right now. That's what he was. Well, not quite - Polish code-breakers cracked the earlier Enigma machines - and it is believed that Turing's WWII work, while not game-changing, accelerated the Allied victory by some years, and saved just several million people.
  2. The maximum sentence was three years imprisonment.
  3. He was found with a half-eaten apple by him. It wasn't tested, but he had earlier talked about the Disney cartoon.
  4. In 1999, Time magazine named him as one the 100 Most Important People of the 20th Century
  5. The voters in a 2002 BBC PollWikipedia ranked him the 21st Greatest Briton of all time - which is quite extraordinary, considering that mathematicians don't usually get many votes in that sort of poll, and that his war work had remained secret until late in the 20th century.
  6. It has been suggested - and it seems entirely plausible that, without Turing's skills in breaking the German naval Enigma codes, the Nazis would have starved Great Britain into submission before the US entered the war following the Japanese attack on Pearl Harbor in December 1941, and long before Uruguay declared war on the Axis powers in February 1945.
  7. The interpretations of the original test/tests vary, but note that the omission of the gender element can easily change a test that involves considering the thoughts/tactics of the other two humans involved and a lot of context and adaptation, to one that chatbots can solve in a disappointingly easy way.
  8. I'm...not even sure who I am anymore.
  9. The British government, unwilling to grant variance from the Official Secrets Act, forbade presentation and consideration of Turing's indispensably vital role in the WWII victory to advocate mitigation in sentencing.
  10. You can observe some of these here.
  11. Wikipedia themselves have been inundated with the claim and can't find anything scholarly to support it.
  12. Stephen Fry once asked Steve Jobs if the Apple logo was based on Turing; Jobs said "God, we wish it were. It's just a coincidence."[1][2]
  13. According to mattsmacintosh on YouTube, the logo had the "bite" because they overlapped the text "Apple Computers" over the apple.