Remembering Alan Turing (23 June 1912 – 7 June 1954) [UPDATE — Alan Turing £50 note enters circulation]

“A new inquiry is long overdue, even if only to dispel any doubts about the true cause of his death—including speculation that he was murdered by the security services (or others). I think murder by state agents is unlikely. There is no known evidence pointing to any such act. However, it is a major failing that this possibility has never been considered or investigated.”

 Peter Tatchell — Human Rights advocate

June 7 2019 — Alan Turing was a mathematician, cryptographer and pioneer of computer science who possessed one of the greatest brains of the 20th century. His life was one of secret triumphs shadowed by public tragedy. It has been estimated that his work shortened the war in Europe by more than two years and saved over fourteen million lives. Follow us on Twitter: @INTEL_TODAY

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Alan Turing was one of the most innovative and brilliant men of the 20th century. His work cracking the Enigma code helped bring WWII to an end, saving countless lives. It’s important to make sure his legacy, which went tragically unacknowledged at the time, isn’t forgotten.

Boris Johnson — Twitter (June 23 2021)

UPDATE (June 23 2021) — Today, the new £50 note featuring Alan Turing goes into circulation on his birthday.

The new £50 note contains advanced security features including two windows and a two-color foil, making it very difficult to counterfeit.

The Bank of England has gifted Bletchley Park a special £50 note bearing the serial number AA01 001941.

It marks the year that Turing’s methods led to Bletchley Park’s ability to regularly break the famous four-rotor Naval Enigma cipher.

RELATED POST: 80 Years Ago — Enigma Machine Captured (May 9 1941)

“Alan Turing was a genius who helped to shorten the war and influence the technology that still shapes our lives today,” Jeremy Fleming, GCHQ director, said.

GCHQ — The UK’s intelligence agency — has also unveiled an artwork of Alan Turing’s portrait inside the wheels of the codebreaking British Bombe machine, placed in the middle of its headquarters to celebrate his legacy.

Turing was very badly treated during his lifetime. Today, he is regarded as a national treasure.

The truth is that Turing was certainly a genius but his ideas played no role whatsoever in the development of early computers.

The importance of his seminal paper — On Computable Numbers (1936) — was not realized until the late 1960s.

Professor Max Newman — Turing’s former Cambridge tutor and leader of the wartime Colossus development at Bletchley Park — described him as “one of the most profound and original mathematical minds of his generation”.

When asked what influence Turing’s On Computable Numbers paper had in the early days of computer design, Newman replied: “I should say practically none at all.” [Simon Lavington — Author of Alan Turing and his Contemporaries: Building the World’s First Computers]


“I believe that at the end of the century the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted.”

Alan Turing

UPDATE (June 7 2021) — [Was Turing murdered by the British Security Service? And why?]

To celebrate Alan Turing featuring on the new £50 banknote, GCHQ has created their hardest puzzle ever in his honour. 

So far, we have worked out the solutions of the first four puzzles. I have also suggested a counter-intuitive solution to puzzle 5.

RELATED POST: GCHQ — Play the TURING Challenge! — How to get the Answer to Puzzle #5… Without solving Puzzle #5 [Think like Turing!]

Today, I would like to tell you about the kind of ‘coincidences’ that tends to catch my attention. As you know, I am a suspicious grumpy old man…

RELATED POST: Letter to a young investigator — Be suspicious of everything! [On the origin of the COVID-19 pandemic]

On May 12 1941, the Z3 computer was presented to an audience of scientists including professors Alfred Teichmann and Curt Schmieden of the Deutsche Versuchsanstalt für Luftfahrt (“German Laboratory for Aviation”) in Berlin.

The Z3 was the world’s first working programmable, fully automatic digital computer. In 1998, the Z3 was demonstrated to be, in principle, Turing-complete.

The Z3 was the brainchild of Konrad Zuse, a German civil engineer, inventor and computer pioneer.

RELATED POST: 80 Years Ago — First Modern Computer Delivered to German Aerospace Institute (May 12 1941)

According to historians, Zuse and Turing only met once, and that meeting took place during a 1947 colloquium in Göttingen.

So, Zuse and Turing hit upon the magnificent idea of modern computers simultaneously and independently.

There is no doubt that important inventions have occurred simultaneously and independently among different inventors.

But I will tell you this much. For my entire life, I have been wondering how two physicists — one Hungarian and the other Japanese — could possibly have made the same discovery at the same time and for the same purpose… After three decades of research, I came to a simple conclusion. One is the inventor. The other is a thief…

There is no doubt that British and US intelligence knew much about the work of Konrad Zuse during World War II. Is it possible that some reports ended on the desk of Alan Turing?

According to Wikipedia, Zuse’s work was totally unknown in the United Kingdom and the United States during World War II. Is that subtle, or what? This much is certain. In early 1946, IBM had already an option on Zuse’s patents. Some people are quick…

If indeed, Turing had access to the work of Zuse on the Z3, then the speculation that he was murdered by the Security Service is not entirely without merit.


“I would not like the journey [to the United States], and I detest America.”

Alan Turing (1953) — Response to a conference invitation

UPDATE (June 7 2020) — Alan Turing has been chosen by the Bank of England to be the new face of its 50-pound note.

The note will feature a photograph of Mr. Turing from 1951 that is now on display at the National Portrait Gallery. His work will also be celebrated on the reverse side, which will include a table and mathematical formulas from a paper by Mr. Turing from 1936 that is recognized as foundational for computer science.

“Alan Turing was an outstanding mathematician whose work has had an enormous impact on how we live today,” Mark Carney, the governor of the Bank of England, said in a statement.

“As the father of computer science and artificial intelligence, as well as a war hero, Alan Turing’s contributions were far-ranging and path breaking.”

“Turing is a giant on whose shoulders so many now stand,” Mr. Carney added.

The note, which will be made of polymer, will go into circulation in 2021. It will feature an image of Turing taken in 1951 and his signature, taken from the visitor’s book at Bletchley Park.

The note will also feature a quote from a 1949 interview about one of the computers he helped develop:

“This is only a foretaste of what is to come, and only the shadow of what is going to be.”

Code breaking computer scientist Alan Turing to be celebrated on £50 note


Alan Mathison Turing (23 June 1912 – 7 June 1954) was an English computer scientist, mathematician, logician, cryptanalyst, philosopher and theoretical biologist.

He was highly influential in the development of theoretical computer science, providing a formalisation of the concepts of algorithm and computation with the Turing machine, which can be considered a model of a general purpose computer. Turing is widely considered to be the father of theoretical computer science and artificial intelligence.

During the Second World War, Turing worked for the Government Code and Cypher School (GC&CS) at Bletchley Park, Britain’s codebreaking centre that produced Ultra intelligence. For a time he led Hut 8, the section responsible for German naval cryptanalysis.

He devised a number of techniques for speeding the breaking of German ciphers, including improvements to the pre-war Polish bombe method, an electromechanical machine that could find settings for the Enigma machine.

Turing played a pivotal role in cracking intercepted coded messages that enabled the Allies to defeat the Nazis in many crucial engagements, including the Battle of the Atlantic, and in so doing helped win the war.

Counterfactual history is difficult with respect to the effect Ultra intelligence had on the length of the war, but at the upper end it has been estimated that this work shortened the war in Europe by more than two years and saved over fourteen million lives. [Wikipedia]

Alan Turing’s Crisis

Andrew Hodges wrote a nice overview of Alan Turing’s life and work.

Alan Turing was arrested and came to trial on 31 March 1952, after the police learned of his sexual relationship with a young Manchester man. He made no serious denial or defence, instead telling everyone that he saw no wrong with his actions. He was particularly concerned to be open about his sexuality even in the hard and unsympathetic atmosphere of Manchester engineering. Rather than go to prison he accepted, for the period of a year, injections of oestrogen intended to neutralise his libido.

His work on the morphogenetic theory continued. He developed his theory of pattern formation out of instability into the realm of spherical objects, such as the Radiolaria, and also on the cylinder, as a model of plant stems. He set as a particular goal the explanation for the appearance of the Fibonacci numbers in the leaf patterns of plants — most noticeable in the close-packed spirals of sunflower heads and fir cones.

In his book “The Chemical Basis of Morphogenesis” (1952), Turing correctly predicted a mechanism of morphogenesis, the diffusion of two different chemical signals, one activating and one deactivating growth, to set up patterns of development.

Besides this he refreshed his youthful interest in quantum physics, studying the problem of wave-function reduction in quantum mechanics, with a hint that he was considering a non-linear mechanism for it. He took a new interest in the representation of elementary particles by spinors, and in relativity theory.

A factor in his life unknown to most around him was that he had also continued to work for GCHQ, the post-war successor to Bletchley Park, on the basis of a personal connection with Alexander, now its director.

But since 1948, the conditions of the Cold War, and the alliance with the United States, meant that known homosexuals had become ineligible for security clearance.

Turing, now therefore excluded, spoke bitterly of this to his onetime wartime colleague, now MI6 engineer Donald Bayley, but to no other personal friends.

State security also seems the likely cause of what he described as another intense crisis in March 1953, involving police searching for a visiting Norwegian who had come to see him.

Concern over the foreign contacts of one acquainted with state secrets was understandable, and his holiday in Greece in 1953 could not have been calculated to calm the nerves of security officers.

Although unable to tell his friends about questions of official secrecy, in other ways he actively sought much greater intimacy of expression with them and with a Jungian therapist.

Eccentric, solitary, gloomy, vivacious, resigned, angry, eager, dissatisfied — these had always been his ever-varying characteristics, and despite the strength that he showed the world in coping with outrageous fortune, no-one could safely have predicted his future course.

He was found by his cleaner when she came in on 8 June 1954. He had died the day before of cyanide poisoning, a half-eaten apple beside his bed.

His mother believed he had accidentally ingested cyanide from his fingers after an amateur chemistry experiment, but it is more credible that he had successfully contrived his death to allow her alone to believe this. The coroner’s verdict was suicide.

[Alan Turing — a short biography by Andrew Hodges]

The 2017 Alan Turing Law

In 2009, following an Internet campaign, British Prime Minister Gordon Brown made an official public apology on behalf of the British government for “the appalling way he was treated.” Queen Elizabeth II granted him a posthumous pardon in 2013.

The Alan Turing law is now an informal term for a 2017 law in the United Kingdom that retroactively pardons men cautioned or convicted under historical legislation that outlawed homosexual acts.

Alan Turing – Celebrating the life of a genius


Alan Turing — a short biography by Andrew Hodges


Remembering Alan Turing [23 June 1912 – 7 June 1954]

Remembering Alan Turing (23 June 1912 – 7 June 1954) [2020]

Remembering Alan Turing (23 June 1912 – 7 June 1954) [Was Turing murdered by the British Security Service? And why?]

Remembering Alan Turing (23 June 1912 – 7 June 1954) [UPDATE — Alan Turing £50 note enters circulation]

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