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Alan Turing, father of modern computing and social outcast

22 mayo, 2021

Alan Turing was a brilliant mathematician, cryptanalyst and computer theoretician born on June 23, 1912 in Maida Vale, a residential district in west London. Turing, in addition to being a brilliant scientist, was homosexual, which it cost him his life June 7, 1954.

Turing is known worldwide for four facts:

  • He formalized the concepts of algorithm Y computing with his turing machine
  • He is considered the father of artificial intelligence
  • Your participation in the cryptanalysis team of the German crypto machine Enigma It was key code
  • He was one more victim of the reactionary puritan mentality of the Anglo-Saxon world

The British Government posthumously made a public apology through Gordon Brown on September 10, 2009 for prosecuting and prosecuting Alan Turing for being homosexual. It is the least paradoxical that Turing was prosecuted and persecuted because of his homosexuality by a government that described as monstrous the acts of Nazism for prosecuting and persecuting individuals for their religious beliefs.

The Turing Machine

A Turing machine is a theoretical device that manipulates symbols on a tape according to a defined table of rules. This computational model can be adapted to simulate the logic of any algorithm and is particularly useful in the work of explaining the operation of a CPU.

The Turing machine was described by Alan Turing in 1936 as a response to the German mathematician David Hilbert’s essay “On Computable Numbers, with an Application to the Entscheidungsproblem“Where he showed that some of these Turing machines would be capable of performing any conceivable mathematical calculation if it were representable with an algorithm. He also proved that there is no solution to the Entscheidungsproblem (decision problem) since it shows that it is not possible to decide, in general, algorithmically if a Turing machine is stopped.


The Turing machine mathematically models a machine that operates on a belt. On this tape are symbols that the machine can write or read, one at a time. The operations that the machine can perform are determined by a finite set of elementary instructions such as “if the state is 6 and the value is 0 write 1 and go to state 27”.

A Turing machine consists of the following parts:

  • A tape that is divided into cells next to each other. Each cell contains a symbol in some finite alphabet. This alphabet contains a special symbol in white (blank symbol written as ‘B’) and one or more additional symbols. The tape is supposed to be infinite.
  • A head that can read and write symbols on the tape and move the tape left or right one position.
  • A table of rules finite of instructions, usually tuples of five elements that given the state (qi) where the machine is currently located and the symbol (aj) that is being read from the tape, instructs the machine to perform the following sequence of actions:
    • Write or delete a symbol
    • Shake your head (left or right)
    • Assume the same or a new status as prescribed
  • A state register where the state of the Turing machine is stored.

Universal Turing Machine

Turing defined that it is possible to develop a only machine that can be used to compute any computable sequence. If this machine OR It is supplied with a tape that in its beginning is written with quintuple tuples separated by semicolons from a machine M, then OR will compute the same sequences what M.

This model of computation represents the fundamental theoretical advance that led to the notion of a stored computer program.

Participation in the fight against Enigma

Enigma machine being used on the Russian front

The Enigma was an electro-mechanical rotor machine used to send encrypted messages by Nazi Germany during World War II. Alan Turing actively participated in the development of cryptographic analysis devices as well as contributing many of the ideas that led to the subsequent success in the breakdown of the encryption algorithm used by the machine and that was a great advance in the victory of the allies in the fight.

Turing specified an electro-mechanical mechanism that aided in the mission to break the algorithm of the Enigma machine. faster what bomb which was the Polish billing device that was being used to date. The new device was called pump being built on the original Polish design.

Bombe improved with suggestions made by mathematician Gordon Welchman, became one of the main automated tools in the fight against the trafficking of messages protected with Enigma by Nazi Germany.

Turing decided to take part in solving the problem with the German naval Enigma because and in his words “cause no one else is doing anything about it so i’ll have to do it myself“. By December 1939, Turing had already solved the essential part of the indicator system that was more complex than that used by other services in Nazi Germany.

The Turing Test

In 1950, Turing addressed the problem of artificial intelligence and proposed the experiment that today is known as the turing test whose intention was to try to define a standard by which it could be known if a machine could be called “smart“.

The idea was that it can be said that a computer “think“If a human interrogator could not distinguish through a conversation, whether you are conversing with a human or a machine. Turing proposed that instead of simulating an artificial mind adult, it was better to simulate a mind childish to subject it later to a learning process.

Prosecution for indecency (homosexuality)

In January 1952, Turing met Arnold Murray outside a movie theater. After a lunch date, Turing invited Murray to spend a weekend at his house, an invitation that Murray accepted despite the fact that did not show up. They met again in Manchester the following Monday, on that occasion, Murray agreed to accompany Turing home.

A few weeks later, Murray visited Turing’s house again, and it appears that they spent the night together. Later, Murray, aided by an accomplice, entered Turing’s house, who reported the incident to the authorities. During the investigation, Turing acknowledged having had a sexual relationship with Murray. Homosexual acts they were illegal in the United Kingdom in 1952 and was therefore charged with gross indecency under article 11 of the Penal Code, which was the same crime for which Oscar Wilde was convicted fifty years ago.

You were given the option of going to prison or parole under agreement to submit to an estrogen-based chemical castration hormone treatment. He accepted her, the treatment produced disastrous side effects as the appearance of breasts and obesity. His security permission was withdrawn and he was banned from continuing his encryption consulting work. His British passport was not revoked but the United States denied him entry into its territory.


On June 8, 1954, Turing was found dead by your cleaning staff. A post-mortem examination established that the cause of death was cyanide poisoning apparently ingested by eating part of an apple bathed in that substance that was also on the table next to his bed.


Since 1966, the Alan Turing Award has been awarded annually by the Association for Computing Machinery to an individual in recognition of their technical contribution to computer science and the Community. This award is considered as the greatest honor in the world of computing, comparable to the Nobel Prize.

Alan Turing was another genius victim of irrationality and morality expires. He died at the age of 41, a few days after turning 42, if Turing’s life had not ended abruptly and violently, surely many other advances would have come from his hand, advances that we will never know if they have been achieved or not.

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More information | The Turing Machine

Image source from Enigma Deutsches Bundesarchiv (German Federal Archive)