Alan Turing, age 16.
Source: https://upload.wikimedia.org/wikipedia/commons/a/a1/Alan_Turing_Aged_16.jpg
Commemorative statue of Turing, currently in Bletchley Park.
Source: https://upload.wikimedia.org/wikipedia/commons/c/c4/AlanTuring-Bletchley.jpg
Alan Turing's invention to crack the ENIGMA code, the Bombe, is recreated above.
Source: https://upload.wikimedia.org/wikipedia/commons/5/5c/Bombe-rebuild.jpg
A plaque on the front of Turing's home in Cheshire.
Source: https://upload.wikimedia.org/wikipedia/commons/1/19/Turing_Plaque.jpg
Essay Question:
How did Turing's accomplishments influence the modern world?
Background Text:
Alan Turing is arguably one of the most important men of the 20th century. In his life he contributed huge amounts to computer science to the extent that the prize called “the Nobel Prize of Computer Science” is called the Turing Award. Indeed, his legacy is memorialized in two movies, an opera, a song, a play, and countless books. However, the most important part of his legacy were his contributions to mathematics, cryptography, and computer science.
In the mid-1930s, Alan Turing was entering the field of mathematics, and at the age of twenty-six, he solved a problem which, when translated, is termed “the Decision Problem”. In this, he described a hypothetical system later called the Turing Machine that can write digits or symbols on tape, shift the tape from left to right, and change “states” based off of the result of previous states and input digits. See Technical Details 1 for details on the machine.
This was published at the same time that another mathematician’s work was published on the same problem and with the same conclusion – that the Decision Problem can’t be solved. Turing’s work was arguably more important, as the concept of Turing Machines survives to the present day. He was essentially describing the first computer, though it wasn’t described as a computer in his paper.
Another one of Turing’s biggest accomplishments is the solution of the ENIGMA machine used by the Germans in World War Two. In October 1942, U-559, one of the German’s U-Boats, was attacked and destroyed, but several weeks worth of ENIGMA code keys and an ENIGMA machine were salvaged, which allowed English cryptographers, including Alan Turing, to read solutions for several weeks. Turing and other English cryptographers used the keys from U-559 to break the ENIGMA code, meaning that even without the cryptographic key used to encode a message, the Allied forces would be able to decode it. It was later said by General Dwight Eisenhower that the solution of the ENIGMA machine saved about two years of warfare and at least two million lives during World War Two. Turing’s findings were declassified in the 1970s.
One of the other concepts Turing created was that of the Turing Test. It regards hypothetical interaction between a computer and a human. Turing’s statement was that a computer that passed a certain test could be regarded as either thinking or faking the process of thought very well. See Technical Details 2 for details on the Turing Test. This is regarded by many as the crucial test of artificial intelligence – passing the Turing Test. However, a program that passes the Turing Test hasn’t been invented yet, even though many attempts have been made, over 50 years since it was conceptualized.
Turing met a tragic end due to the fact that he was a homosexual becoming known by the British authorities after a lover's friend broke in. This was a crime in Great Britain at the time, and Turing was punished for that by being chemically castrated. In 1954, he apparently committed suicide by eating an apple that he laced with cyanide.
Timeline:
- 1912: Alan Mathison Turing was born in London.
- 1918-1930: Attended primary school. He also learned science and mathematics - he was able to deduce that a text of Einstein's was questioning of Newton's Laws of Motion when the Laws of Motion were never mentioned.
- 1930: Became great friends (possibly in a relationship) with Christopher Morcom. However, Morcom died before Turing applied to university.
- 1931-1935: Turing went to King's College in Cambridge. He authored a paper at the age of 23 and became a Fellow there.
- 1936: He published the paper On Computable Numbers and an Application to the Entscheidungsproblem, solving an unsolved problem in mathematics. This was solved with the concept of a Universal Machine (aka Turing Machine).
- 1936-1938: Studied under cryptographer Alonzo Church at Princeton. He earned a PhD.
- 1938-1943: Worked at Bletchley Park, where he solved the ENIGMA machine's codes - that is, for any encrypted message, his machine could decrypt it.
- 1945: Joined National Physical Laboratory and designed the Automatic Computing Engine. NPL did not have the resources to fund his proposal, however.
- 1949-1950: Worked on software for the Manchester Mark 1 computer. He also formalizes the Turing Test and designs a chess program.
- 1952: Met Andrew Murray and got in a relationship with him. Murray later helps a friend of his break into Turing's house. Turing reported the act and got arrested for homosexuality charges. He is given the option of prison or oestrogen injections, a form of chemical castration.
- June 8 1954: Apparently poisoned himself via an apple laced with cyanide. (He was doing experiments using cyanide beforehand, so some question remains as to whether it was suicide or accidental.)
- 2009: The former British Prime Minister pardoned Turing and issues a statement of apology on behalf of the British government.
Technical Details:
- As Charles Petzold writes in “The Annotated Turing”, Turing illustrated that both the sequence 010101 ad infinitum and 010110111… ad infinitum were printable using this hypothetical device; Turing even proved that any number that could be computed using an algebraic formula could be printed out by this – this even included pi and e. Turing also showed the existence of a “Universal Machine” that could simulate the operation of any other Turing Machine. This concept was made in order to prove the Decision Problem, which was an open question at the time. The decision problem asks, in modern terminology, whether a program can analyze mathematical statements and determine that they are provable. Turing showed the solution to the Decision Problem by defining these machines and proving that it’s impossible one machine to simulate another without running the machine itself. He then constructs a statement in mathematical logic equivalent to a machine that gives True whenever another given machine will print 0 and False otherwise. However, he established that this was unprovable earlier, thus the Decision Problem is unsolvable.
- Have a human judge and the thinking computer interact via text only and have the judge and another human interact via text only. Afterwards, ask the judge to select whether he thought the human was the first participant and the computer the second or vice versa.
Hodges, Andrew and Douglas R Hofstadter. Alan Turing. New Jersey: Princeton University Press, 2012. Print.
Hodges, Andrew. Turing. New York: Routledge, 1999. Print.
Leavitt, David. The Man Who Knew Too Much. New York: W.W. Norton, 2006. Print.
Turing, Alan Mathison and B. Jack Copeland. The Essential Turing. Oxford: Clarendon Press, 2004. Print.
Turing, Sara. Alan M. Turing. Print.
Websites about Turing:
http://www.turing.org.uk/ is the de facto biography of Turing by Andrew Hodges, mathematician and biographer of Turing.
http://www.biography.com/people/alan-turing-9512017 is a shorter biography of Turing.http://www.bbc.co.uk/timelines/z8bgr82 is an excellent timeline that illustrates almost all of Turing's achievements (some of which have been left out).
http://www.alanturing.net/ is an archive of his papers and commentary explaining them and includes a biography.
https://www.britannica.com/biography/Alan-Turing is from the Encyclopedia Britannica and a excellent summary of his achievements.
http://www.mathcomp.leeds.ac.uk/turing2012 is a centenary compilation of articles and videos about Turing.
http://www.turingfilm.com/dvd-digital is a movie about Turing, available on Hulu and Netflix.
https://vimeo.com/12016718 is a short 4-minute video about Turing's influence on the modern world.
https://www.youtube.com/watch?v=3k1NbD1n7b0 is a talk about Turing by the historian of MI5 (the British spy agency).
https://www.youtube.com/watch?v=paZY5SDYRZs is a luncheon talk about Alan Turing given in 2012.
