Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician,
computer scientist,
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...
ian,
cryptanalyst
Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic sec ...
, philosopher, and
theoretical biologist. Turing was highly influential in the development of
theoretical computer science
Theoretical computer science (TCS) is a subset of general computer science and mathematics that focuses on mathematical aspects of computer science such as the theory of computation, lambda calculus, and type theory.
It is difficult to circumsc ...
, providing a formalisation of the concepts of
algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
and
computation with the
Turing machine
A Turing machine is a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, it is capable of implementing any computer algori ...
, which can be considered a model of a
general-purpose computer.
[ He is widely considered to be the father of theoretical computer science and ]artificial intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech r ...
.
Born in Maida Vale
Maida Vale ( ) is an affluent residential district consisting of the northern part of Paddington in West London, west of St John's Wood and south of Kilburn. It is also the name of its main road, on the continuous Edgware Road. Maida Vale is ...
, London, Turing was raised in southern England
Southern England, or the South of England, also known as the South, is an area of England consisting of its southernmost part, with cultural, economic and political differences from the Midlands and the North. Officially, the area includes ...
. He graduated at King's College, Cambridge
King's College is a constituent college of the University of Cambridge. Formally The King's College of Our Lady and Saint Nicholas in Cambridge, the college lies beside the River Cam and faces out onto King's Parade in the centre of the cit ...
, with a degree in mathematics. Whilst he was a fellow
A fellow is a concept whose exact meaning depends on context.
In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements.
Within the context of higher education ...
at Cambridge, he published a proof demonstrating that some purely mathematical yes–no questions can never be answered by computation and defined a Turing machine
A Turing machine is a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, it is capable of implementing any computer algori ...
, and went on to prove that the halting problem
In computability theory, the halting problem is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running, or continue to run forever. Alan Turing proved in 1936 that a ...
for Turing machines is undecidable. In 1938, he obtained his PhD from the Department of Mathematics
Department may refer to:
* Departmentalization, division of a larger organization into parts with specific responsibility
Government and military
*Department (administrative division), a geographical and administrative division within a country, ...
at Princeton University
Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
. During the Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, Turing worked for the Government Code and Cypher School
Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Uni ...
(GC&CS) at Bletchley Park
Bletchley Park is an English country house and estate in Bletchley, Milton Keynes ( Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years followin ...
, Britain's codebreaking
Cryptanalysis (from the Greek ''kryptós'', "hidden", and ''analýein'', "to analyze") refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic sec ...
centre that produced Ultra
adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park. ' ...
intelligence. For a time he led Hut 8
Hut 8 was a section in the Government Code and Cypher School (GC&CS) at Bletchley Park (the British World War II codebreaking station, located in Buckinghamshire) tasked with solving German naval ( Kriegsmarine) Enigma messages. The section was ...
, the section that was responsible for German naval cryptanalysis. Here, he devised a number of techniques for speeding the breaking of German ciphers, including improvements to the pre-war Polish bomba method, an electromechanical
In engineering, electromechanics combines processes and procedures drawn from electrical engineering and mechanical engineering. Electromechanics focuses on the interaction of electrical and mechanical systems as a whole and how the two systems ...
machine that could find settings for the Enigma machine. Turing played a crucial role in cracking intercepted coded messages that enabled the Allies to defeat the Axis powers
The Axis powers, ; it, Potenze dell'Asse ; ja, 枢軸国 ''Sūjikukoku'', group=nb originally called the Rome–Berlin Axis, was a military coalition that initiated World War II and fought against the Allies. Its principal members were ...
in many crucial engagements, including the Battle of the Atlantic.
After the war, Turing worked at the National Physical Laboratory, where he designed the Automatic Computing Engine
The Automatic Computing Engine (ACE) was a British early Electronic storage, electronic Serial computer, serial stored-program computer designed by Alan Turing. It was based on the earlier Pilot ACE. It led to the MOSAIC computer, the Bendi ...
(ACE), one of the first designs for a stored-program computer. In 1948, Turing joined Max Newman
Maxwell Herman Alexander Newman, FRS, (7 February 1897 – 22 February 1984), generally known as Max Newman, was a British mathematician and codebreaker. His work in World War II led to the construction of Colossus, the world's first operatio ...
's Computing Machine Laboratory
The Computing Machine Laboratory at the University of Manchester in the north of England was established by Max Newman shortly after the end of World War II, around 1946.
The Laboratory was funded through a grant from the Royal Society, which was ...
, at the Victoria University of Manchester
The Victoria University of Manchester, usually referred to as simply the University of Manchester, was a university in Manchester, England. It was founded in 1851 as Owens College. In 1880, the college joined the federal Victoria University. Afte ...
, where he helped develop the Manchester computers
The Manchester computers were an innovative series of stored-program electronic computers developed during the 30-year period between 1947 and 1977 by a small team at the University of Manchester, under the leadership of Tom Kilburn. They includ ...
and became interested in mathematical biology. He wrote a paper on the chemical basis of morphogenesis
Morphogenesis (from the Greek ''morphê'' shape and ''genesis'' creation, literally "the generation of form") is the biological process that causes a cell, tissue or organism to develop its shape. It is one of three fundamental aspects of deve ...
and predicted oscillating
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum ...
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
s such as the Belousov–Zhabotinsky reaction
A Belousov–Zhabotinsky reaction, or BZ reaction, is one of a class of reactions that serve as a classical example of non-equilibrium thermodynamics, resulting in the establishment of a nonlinear chemical oscillator. The only common element in ...
, first observed in the 1960s. Despite these accomplishments, Turing was never fully recognised in Britain during his lifetime because much of his work was covered by the Official Secrets Act.
Turing was prosecuted in 1952 for homosexual acts
Homosexuality is romantic attraction, sexual attraction, or sexual behavior between members of the same sex or gender. As a sexual orientation, homosexuality is "an enduring pattern of emotional, romantic, and/or sexual attractions" to peo ...
. He accepted hormone treatment with DES
Des is a masculine given name, mostly a short form (hypocorism) of Desmond. People named Des include:
People
* Des Buckingham, English football manager
* Des Corcoran, (1928–2004), Australian politician
* Des Dillon (disambiguation), sever ...
, a procedure commonly referred to as chemical castration
Chemical castration is castration via anaphrodisiac drugs, whether to reduce libido and sexual activity, to treat cancer, or otherwise. Unlike surgical castration, where the gonads are removed through an incision in the body, , as an alternative to prison. Turing died on 7 June 1954, 16 days before his 42nd birthday, from cyanide poisoning
Cyanide poisoning is poisoning that results from exposure to any of a number of forms of cyanide. Early symptoms include headache, dizziness, fast heart rate, shortness of breath, and vomiting. This phase may then be followed by seizures, sl ...
. An inquest determined his death as a suicide, but it has been noted that the known evidence is also consistent with accidental poisoning.
Following a public campaign in 2009, the British Prime Minister Gordon Brown
James Gordon Brown (born 20 February 1951) is a British former politician who served as Prime Minister of the United Kingdom and Leader of the Labour Party from 2007 to 2010. He previously served as Chancellor of the Exchequer in Tony B ...
made an official public apology on behalf of the British government for "the appalling way uringwas treated". Queen Elizabeth II
Elizabeth II (Elizabeth Alexandra Mary; 21 April 1926 – 8 September 2022) was Queen of the United Kingdom and other Commonwealth realms from 6 February 1952 until Death and state funeral of Elizabeth II, her death in 2022. She was queen ...
granted a posthumous pardon in 2013. The term " Alan Turing law" is now used informally to refer to a 2017 law in the United Kingdom that retroactively pardoned men cautioned or convicted under historical legislation that outlawed homosexual acts.
Turing has an extensive legacy with statues of him and many things named after him, including an annual award for computer science innovations. He appears on the current Bank of England £50 note, which was released on 23 June 2021, to coincide with his birthday. A 2019 BBC series, as voted by the audience, named him the greatest person of the 20th century.
Early life and education
Family
Turing was born in Maida Vale
Maida Vale ( ) is an affluent residential district consisting of the northern part of Paddington in West London, west of St John's Wood and south of Kilburn. It is also the name of its main road, on the continuous Edgware Road. Maida Vale is ...
, London, while his father, Julius Mathison Turing (1873–1947), was on leave from his position with the Indian Civil Service
The Indian Civil Service (ICS), officially known as the Imperial Civil Service, was the higher civil service of the British Empire in India during British rule in the period between 1858 and 1947.
Its members ruled over more than 300 million ...
(ICS) of the British Raj government at Chatrapur
Chhatrapur (also spelt as Chhatarpur) is a town and a Notified Area Council since 1955 in Ganjam district in the state of Odisha, India. It is the district headquarters town of Ganjam district. Chhatrapur is a Tehsil / Block (CD) in the Ganja ...
, then in the Madras Presidency and presently in Odisha
Odisha (English: , ), formerly Orissa ( the official name until 2011), is an Indian state located in Eastern India. It is the 8th largest state by area, and the 11th largest by population. The state has the third largest population of ...
state, in India. Turing's father was the son of a clergyman, the Rev. John Robert Turing, from a Scottish family of merchants that had been based in the Netherlands and included a baronet
A baronet ( or ; abbreviated Bart or Bt) or the female equivalent, a baronetess (, , or ; abbreviation Btss), is the holder of a baronetcy, a hereditary title awarded by the British Crown. The title of baronet is mentioned as early as the 14th ...
. Turing's mother, Julius's wife, was Ethel Sara Turing (; 1881–1976), daughter of Edward Waller Stoney, chief engineer of the Madras Railways. The Stoneys were a Protestant
Protestantism is a Christian denomination, branch of Christianity that follows the theological tenets of the Reformation, Protestant Reformation, a movement that began seeking to reform the Catholic Church from within in the 16th century agai ...
Anglo-Irish gentry
Gentry (from Old French ''genterie'', from ''gentil'', "high-born, noble") are "well-born, genteel and well-bred people" of high social class, especially in the past.
Word similar to gentle imple and decentfamilies
''Gentry'', in its widest c ...
family from both County Tipperary
County Tipperary ( ga, Contae Thiobraid Árann) is a county in Ireland. It is in the province of Munster and the Southern Region. The county is named after the town of Tipperary, and was established in the early 13th century, shortly after t ...
and County Longford, while Ethel herself had spent much of her childhood in County Clare
County Clare ( ga, Contae an Chláir) is a county in Ireland, in the Southern Region and the province of Munster, bordered on the west by the Atlantic Ocean. Clare County Council is the local authority. The county had a population of 118,81 ...
. Julius and Ethel married on 1 October 1907 at Batholomew's church on Clyde Road, in Dublin.
Julius's work with the ICS brought the family to British India, where his grandfather had been a general in the Bengal Army. However, both Julius and Ethel wanted their children to be brought up in Britain, so they moved to Maida Vale
Maida Vale ( ) is an affluent residential district consisting of the northern part of Paddington in West London, west of St John's Wood and south of Kilburn. It is also the name of its main road, on the continuous Edgware Road. Maida Vale is ...
, London, where Alan Turing was born on 23 June 1912, as recorded by a blue plaque
A blue plaque is a permanent sign installed in a public place in the United Kingdom and elsewhere to commemorate a link between that location and a famous person, event, or former building on the site, serving as a historical marker. The term i ...
on the outside of the house of his birth, later the Colonnade Hotel. Turing had an elder brother, John (the father of Sir John Dermot Turing, 12th Baronet of the Turing baronets).
Turing's father's civil service commission was still active and during Turing's childhood years, his parents travelled between Hastings
Hastings () is a large seaside town and borough in East Sussex on the south coast of England,
east to the county town of Lewes and south east of London. The town gives its name to the Battle of Hastings, which took place to the north-west ...
in the United Kingdom and India, leaving their two sons to stay with a retired Army
An army (from Old French ''armee'', itself derived from the Latin verb ''armāre'', meaning "to arm", and related to the Latin noun ''arma'', meaning "arms" or "weapons"), ground force or land force is a fighting force that fights primarily on ...
couple. At Hastings, Turing stayed at Baston Lodge
Baston Lodge is a residential villa in St Leonards-on-Sea, Hastings, East Sussex, southern England.
The building was designed by Decimus Burton (1800–1881) as a seaside villa for John Ward, a friend, and completed in 1850. The architecture is ...
, Upper Maze Hill, St Leonards-on-Sea, now marked with a blue plaque. The plaque was unveiled on 23 June 2012, the centenary of Turing's birth.
Very early in life, Turing showed signs of the genius that he was later to display prominently. His parents purchased a house in Guildford
Guildford ()
is a town in west Surrey, around southwest of central London. As of the 2011 census, the town has a population of about 77,000 and is the seat of the wider Borough of Guildford, which had around inhabitants in . The name "Guildf ...
in 1927, and Turing lived there during school holidays. The location is also marked with a blue plaque.
School
Turing's parents enrolled him at St Michael's, a primary school at 20 Charles Road, St Leonards-on-Sea, from the age of six to nine. The headmistress recognised his talent, noting that she has "...had clever boys and hardworking boys, but Alan is a genius."
Between January 1922 and 1926, Turing was educated at Hazelhurst Preparatory School, an independent school in the village of Frant
Frant is a village and civil parish in the Wealden District of East Sussex, England, on the Kentish border about three miles (5 km) south of Royal Tunbridge Wells.
When the iron industry was at its height, much of the village was owned ...
in Sussex (now East Sussex). In 1926, at the age of 13, he went on to Sherborne School
(God and My Right)
, established = 705 by Aldhelm,
re-founded by King Edward VI 1550
, closed =
, type = Public school Independent, boarding school
, religion = Church of England
, president =
, chair_label = Chairman of the governors
, ...
, a boarding independent school in the market town of Sherborne
Sherborne is a market town and civil parish in north west Dorset, in South West England. It is sited on the River Yeo, on the edge of the Blackmore Vale, east of Yeovil. The parish includes the hamlets of Nether Coombe and Lower Clatcombe. ...
in Dorset, where he boarded at Westcott House. The first day of term coincided with the 1926 General Strike, in Britain, but Turing was so determined to attend that he rode his bicycle unaccompanied from Southampton
Southampton () is a port city in the ceremonial county of Hampshire in southern England. It is located approximately south-west of London and west of Portsmouth. The city forms part of the South Hampshire built-up area, which also covers Po ...
to Sherborne, stopping overnight at an inn.
Turing's natural inclination towards mathematics and science did not earn him respect from some of the teachers at Sherborne, whose definition of education placed more emphasis on the classics
Classics or classical studies is the study of classical antiquity. In the Western world, classics traditionally refers to the study of Classical Greek and Roman literature and their related original languages, Ancient Greek and Latin. Classics ...
. His headmaster wrote to his parents: "I hope he will not fall between two stools. If he is to stay at public school, he must aim at becoming ''educated''. If he is to be solely a ''Scientific Specialist'', he is wasting his time at a public school". Despite this, Turing continued to show remarkable ability in the studies he loved, solving advanced problems in 1927 without having studied even elementary calculus
Calculus, originally called infinitesimal calculus or "the calculus of infinitesimals", is the mathematical study of continuous change, in the same way that geometry is the study of shape, and algebra is the study of generalizations of arithm ...
. In 1928, aged 16, Turing encountered Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...
's work; not only did he grasp it, but it is possible that he managed to deduce Einstein's questioning of Newton's laws of motion
Newton's laws of motion are three basic laws of classical mechanics that describe the relationship between the motion of an object and the forces acting on it. These laws can be paraphrased as follows:
# A body remains at rest, or in moti ...
from a text in which this was never made explicit.
Christopher Morcom
At Sherborne, Turing formed a significant friendship with fellow pupil Christopher Collan Morcom (13 July 1911 – 13 February 1930), who has been described as Turing's "first love". Their relationship provided inspiration in Turing's future endeavours, but it was cut short by Morcom's death, in February 1930, from complications of bovine tuberculosis
Bovines (subfamily Bovinae) comprise a diverse group of 10 genera of medium to large-sized ungulates, including cattle, bison, African buffalo, water buffalos, and the four-horned and spiral-horned antelopes. The evolutionary relationship betwee ...
, contracted after drinking infected cow's milk some years previously.
The event caused Turing great sorrow. He coped with his grief by working that much harder on the topics of science and mathematics that he had shared with Morcom. In a letter to Morcom's mother, Frances Isobel Morcom (née Swan), Turing wrote:
Turing's relationship with Morcom's mother continued long after Morcom's death, with her sending gifts to Turing, and him sending letters, typically on Morcom's birthday. A day before the third anniversary of Morcom's death (13 February 1933), he wrote to Mrs. Morcom:
Some have speculated that Morcom's death was the cause of Turing's atheism
Atheism, in the broadest sense, is an absence of belief in the existence of deities. Less broadly, atheism is a rejection of the belief that any deities exist. In an even narrower sense, atheism is specifically the position that there no d ...
and materialism. Apparently, at this point in his life he still believed in such concepts as a spirit, independent of the body and surviving death. In a later letter, also written to Morcom's mother, Turing wrote:
University and work on computability
After Sherborne, Turing studied as an undergraduate from 1931 to 1934 at King's College, Cambridge
King's College is a constituent college of the University of Cambridge. Formally The King's College of Our Lady and Saint Nicholas in Cambridge, the college lies beside the River Cam and faces out onto King's Parade in the centre of the cit ...
, where he was awarded first-class honours in mathematics. In 1935, at the age of 22, he was elected a Fellow
A fellow is a concept whose exact meaning depends on context.
In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements.
Within the context of higher education ...
of King's College on the strength of a dissertation in which he proved a version of the central limit theorem
In probability theory, the central limit theorem (CLT) establishes that, in many situations, when independent random variables are summed up, their properly normalized sum tends toward a normal distribution even if the original variables themsel ...
. Unknown to Turing, this version of the theorem had already been proven, in 1922, by Jarl Waldemar Lindeberg
Jarl Waldemar Lindeberg (4 August 1876, Helsinki – 24 December 1932, Helsinki) was a Finnish mathematician known for work on the central limit theorem.
Life and work
Lindeberg was son of a teacher at the Helsinki Polytechnical Institute and at ...
. Despite this, the committee found Turing's methods original and so regarded the work worthy of consideration for the fellowship. Abram Besicovitch
Abram Samoilovitch Besicovitch (or Besikovitch) (russian: link=no, Абра́м Само́йлович Безико́вич; 23 January 1891 – 2 November 1970) was a Russian mathematician, who worked mainly in England. He was born in Berdyansk ...
's report for the committee went so far as to say that if Turing's work had been published before Lindeberg's, it would have been "an important event in the mathematical literature of that year".
In 1936, Turing published his paper "". It was published in the ''Proceedings of the London Mathematical Society'' journal in two parts, the first on 30 November and the second on 23 December. In this paper, Turing reformulated Kurt Gödel's 1931 results on the limits of proof and computation, replacing Gödel's universal arithmetic-based formal language with the formal and simple hypothetical devices that became known as Turing machine
A Turing machine is a mathematical model of computation describing an abstract machine that manipulates symbols on a strip of tape according to a table of rules. Despite the model's simplicity, it is capable of implementing any computer algori ...
s. The ''Entscheidungsproblem
In mathematics and computer science, the ' (, ) is a challenge posed by David Hilbert and Wilhelm Ackermann in 1928. The problem asks for an algorithm that considers, as input, a statement and answers "Yes" or "No" according to whether the state ...
'' (decision problem) was originally posed by German mathematician David Hilbert in 1928. Turing proved that his "universal computing machine" would be capable of performing any conceivable mathematical computation if it were representable as an algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algorithms are used as specificat ...
. He went on to prove that there was no solution to the ''decision problem'' by first showing that the halting problem
In computability theory, the halting problem is the problem of determining, from a description of an arbitrary computer program and an input, whether the program will finish running, or continue to run forever. Alan Turing proved in 1936 that a ...
for Turing machines is undecidable: it is not possible to decide algorithmically whether a Turing machine will ever halt. This paper has been called "easily the most influential math paper in history".
Although Turing's proof
Turing's proof is a proof by Alan Turing, first published in January 1937 with the title "On Computable Numbers, with an Application to the ". It was the second proof (after Church's theorem) of the negation of Hilbert's ; that is, the conjecture ...
was published shortly after Alonzo Church
Alonzo Church (June 14, 1903 – August 11, 1995) was an American mathematician, computer scientist, logician, philosopher, professor and editor who made major contributions to mathematical logic and the foundations of theoretical computer scien ...
's equivalent proof using his lambda calculus, Turing's approach is considerably more accessible and intuitive than Church's. It also included a notion of a 'Universal Machine' (now known as a universal Turing machine
In computer science, a universal Turing machine (UTM) is a Turing machine that can simulate an arbitrary Turing machine on arbitrary input. The universal machine essentially achieves this by reading both the description of the machine to be simu ...
), with the idea that such a machine could perform the tasks of any other computation machine (as indeed could Church's lambda calculus). According to the Church–Turing thesis, Turing machines and the lambda calculus are capable of computing anything that is computable. John von Neumann
John von Neumann (; hu, Neumann János Lajos, ; December 28, 1903 – February 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist, engineer and polymath. He was regarded as having perhaps the widest cove ...
acknowledged that the central concept of the modern computer was due to Turing's paper. To this day, Turing machines are a central object of study in theory of computation
In theoretical computer science and mathematics, the theory of computation is the branch that deals with what problems can be solved on a model of computation, using an algorithm, how algorithmic efficiency, efficiently they can be solved or t ...
.
From September 1936 to July 1938, Turing spent most of his time studying under Church at Princeton University
Princeton University is a private university, private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth, New Jersey, Elizabeth as the College of New Jersey, Princeton is the List of Colonial Colleges, fourth-oldest ins ...
, in the second year as a Jane Eliza Procter Visiting Fellow. In addition to his purely mathematical work, he studied cryptology and also built three of four stages of an electro-mechanical binary multiplier
A binary multiplier is an electronic circuit used in digital electronics, such as a computer, to multiply two binary numbers.
A variety of computer arithmetic techniques can be used to implement a digital multiplier. Most techniques involve comp ...
. In June 1938, he obtained his PhD from the Department of Mathematics
Department may refer to:
* Departmentalization, division of a larger organization into parts with specific responsibility
Government and military
*Department (administrative division), a geographical and administrative division within a country, ...
at Princeton; his dissertation, '' Systems of Logic Based on Ordinals'', introduced the concept of ordinal logic In mathematics, ordinal logic is a logic associated with an ordinal number by recursively adding elements to a sequence of previous logics.Solomon Feferman, ''Turing in the Land of O(z)'' in "The universal Turing machine: a half-century survey" by R ...
and the notion of relative computing, in which Turing machines are augmented with so-called oracles, allowing the study of problems that cannot be solved by Turing machines. John von Neumann wanted to hire him as his postdoctoral assistant, but he went back to the United Kingdom.
Career and research
When Turing returned to Cambridge, he attended lectures given in 1939 by Ludwig Wittgenstein
Ludwig Josef Johann Wittgenstein ( ; ; 26 April 1889 – 29 April 1951) was an Austrian-British philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He is con ...
about the foundations of mathematics
Foundations of mathematics is the study of the philosophical and logical and/or algorithmic basis of mathematics, or, in a broader sense, the mathematical investigation of what underlies the philosophical theories concerning the nature of mathe ...
. The lectures have been reconstructed verbatim, including interjections from Turing and other students, from students' notes. Turing and Wittgenstein argued and disagreed, with Turing defending formalism
Formalism may refer to:
* Form (disambiguation)
* Formal (disambiguation)
* Legal formalism, legal positivist view that the substantive justice of a law is a question for the legislature rather than the judiciary
* Formalism (linguistics)
* Scie ...
and Wittgenstein propounding his view that mathematics does not discover any absolute truths, but rather invents them.
Cryptanalysis
During the Second World War, Turing was a leading participant in the breaking of German ciphers at Bletchley Park
Bletchley Park is an English country house and estate in Bletchley, Milton Keynes ( Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years followin ...
. The historian and wartime codebreaker Asa Briggs
Asa Briggs, Baron Briggs (7 May 1921 – 15 March 2016) was an English historian. He was a leading specialist on the Victorian era, and the foremost historian of broadcasting in Britain. Briggs achieved international recognition during his lon ...
has said, "You needed exceptional talent, you needed genius at Bletchley and Turing's was that genius."
From September 1938, Turing worked part-time with the Government Code and Cypher School
Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Uni ...
(GC&CS), the British codebreaking organisation. He concentrated on cryptanalysis of the Enigma cipher machine used by Nazi Germany
Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
, together with Dilly Knox
Alfred Dillwyn "Dilly" Knox, CMG (23 July 1884 – 27 February 1943) was a British classics scholar and papyrologist at King's College, Cambridge and a codebreaker. As a member of the Room 40 codebreaking unit he helped decrypt the Zimm ...
, a senior GC&CS codebreaker. Soon after the July 1939 meeting near Warsaw
Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officia ...
at which the Polish Cipher Bureau gave the British and French details of the wiring of Enigma machine's rotors and their method of decrypting Enigma machine's messages, Turing and Knox developed a broader solution. The Polish method relied on an insecure indicator
Indicator may refer to:
Biology
* Environmental indicator of environmental health (pressures, conditions and responses)
* Ecological indicator of ecosystem health (ecological processes)
* Health indicator, which is used to describe the health ...
procedure that the Germans were likely to change, which they in fact did in May 1940. Turing's approach was more general, using crib-based decryption for which he produced the functional specification of the bombe
The bombe () was an electro-mechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II. The US Navy and US Army later produced their own machines to the same functi ...
(an improvement on the Polish Bomba).
On 4 September 1939, the day after the UK declared war on Germany, Turing reported to Bletchley Park, the wartime station of GC&CS.[Copeland, 2006 p. 378.] Like all others who came to Bletchley, he was required to sign the Official Secrets Act, in which he agreed not to disclose anything about his work at Bletchley, with severe legal penalties for violating the Act.
Specifying the bombe was the first of five major cryptanalytical advances that Turing made during the war. The others were: deducing the indicator procedure used by the German navy; developing a statistical procedure dubbed ''Banburismus
Banburismus was a cryptanalytic process developed by Alan Turing at Bletchley Park in Britain during the Second World War. It was used by Bletchley Park's Hut 8 to help break German ''Kriegsmarine'' (naval) messages enciphered on Enigma machin ...
'' for making much more efficient use of the bombes; developing a procedure dubbed ''Turingery
Turingery in ''Testery Methods 1942–1944'' or Turing's method (playfully dubbed Turingismus by Peter Ericsson, Peter Hilton and Donald Michie) was a manual codebreaking method devised in July 1942 by the mathematician and cryptanalyst Alan Turi ...
'' for working out the cam settings of the wheels of the Lorenz SZ 40/42
The Lorenz SZ40, SZ42a and SZ42b were German rotor stream cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. The model name ''SZ'' was derived from ''Schlüssel-Zusatz'', meaning ''ciph ...
(''Tunny'') cipher machine and, towards the end of the war, the development of a portable secure voice
Secure voice (alternatively secure speech or ciphony) is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.
History
The implementation of voice encryption dat ...
scrambler at Hanslope Park
Hanslope Park is located about half a mile south-east of the village of Hanslope in the City of Milton Keynes, Buckinghamshire, England. Once the manorial estate of the village, it is now owned by the UK Foreign, Commonwealth and Development Of ...
that was codenamed ''Delilah''.
By using statistical techniques to optimise the trial of different possibilities in the code breaking process, Turing made an innovative contribution to the subject. He wrote two papers discussing mathematical approaches, titled ''The Applications of Probability to Cryptography'' and ''Paper on Statistics of Repetitions'', which were of such value to GC&CS and its successor GCHQ
Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Uni ...
that they were not released to the UK National Archives
, type = Non-ministerial department
, seal =
, nativename =
, logo = Logo_of_The_National_Archives_of_the_United_Kingdom.svg
, logo_width = 150px
, logo_caption =
, formed =
, preceding1 =
, dissolved =
, superseding =
, juris ...
until April 2012, shortly before the centenary of his birth. A GCHQ mathematician, "who identified himself only as Richard," said at the time that the fact that the contents had been restricted under the Official Secrets Act for some 70 years demonstrated their importance, and their relevance to post-war cryptanalysis:
Turing had a reputation for eccentricity at Bletchley Park. He was known to his colleagues as "Prof" and his treatise on Enigma was known as the "Prof's Book". According to historian Ronald Lewin
George Ronald Lewin CBE (11 October 1914 – 6 January 1984), later known as Ronald Lewin, was a British officer, publishing editor, radio producer and military historian.
Education
Lewin attended University of Oxford at The Queens College on an ...
, Jack Good, a cryptanalyst who worked with Turing, said of his colleague:
Peter Hilton
Peter John Hilton (7 April 1923Peter Hilton, "On all Sorts of Automorphisms", '' The American Mathematical Monthly'', 92(9), November 1985, p. 6506 November 2010) was a British mathematician, noted for his contributions to homotopy theory and ...
recounted his experience working with Turing in Hut 8
Hut 8 was a section in the Government Code and Cypher School (GC&CS) at Bletchley Park (the British World War II codebreaking station, located in Buckinghamshire) tasked with solving German naval ( Kriegsmarine) Enigma messages. The section was ...
in his "Reminiscences of Bletchley Park" from ''A Century of Mathematics in America:''
Hilton echoed similar thoughts in the Nova PBS
The Public Broadcasting Service (PBS) is an American public broadcasting, public broadcaster and Non-commercial activity, non-commercial, Terrestrial television, free-to-air television network based in Arlington, Virginia. PBS is a publicly fu ...
documentary ''Decoding Nazi Secrets''.
While working at Bletchley, Turing, who was a talented long-distance runner, occasionally ran the to London when he was needed for meetings, and he was capable of world-class marathon standards. Turing tried out for the 1948 British Olympic team, but he was hampered by an injury. His tryout time for the marathon was only 11 minutes slower than British silver medallist Thomas Richards' Olympic race time of 2 hours 35 minutes. He was Walton Athletic Club's best runner, a fact discovered when he passed the group while running alone. When asked why he ran so hard in training he replied:
Due to the problems of counterfactual history
Counterfactual history (also virtual history) is a form of historiography that attempts to answer the '' What if?'' questions that arise from counterfactual conditions. As a method of intellectual enquiry, counterfactual history explores histor ...
, it is hard to estimate the precise effect Ultra intelligence had on the war. However, official war historian Harry Hinsley
Sir Francis Harry Hinsley, (26 November 1918 – 16 February 1998) was an English historian and cryptanalyst. He worked at Bletchley Park during the Second World War and wrote widely on the history of international relations and British Int ...
estimated that this work shortened the war in Europe by more than two years and saved over 14 million lives.[ Transcript of a lecture given on Tuesday 19 October 1993 at Cambridge University]
At the end of the war, a memo was sent to all those who had worked at Bletchley Park, reminding them that the code of silence dictated by the Official Secrets Act did not end with the war but would continue indefinitely. Thus, even though Turing was appointed an Officer of the Order of the British Empire (OBE) in 1946 by King George VI
George VI (Albert Frederick Arthur George; 14 December 1895 – 6 February 1952) was King of the United Kingdom and the Dominions of the British Commonwealth from 11 December 1936 until his death in 1952. He was also the last Emperor of I ...
for his wartime services, his work remained secret for many years.
Bombe
Within weeks of arriving at Bletchley Park, Turing had specified an electromechanical machine called the bombe
The bombe () was an electro-mechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II. The US Navy and US Army later produced their own machines to the same functi ...
, which could break Enigma more effectively than the Polish '' bomba kryptologiczna'', from which its name was derived. The bombe, with an enhancement suggested by mathematician Gordon Welchman
William Gordon Welchman (15 June 1906 – 8 October 1985) was a British mathematician. During World War II, he worked at Britain's secret codebreaking centre, "Station X" at Bletchley Park, where he was one of the most important contributors. ...
, became one of the primary tools, and the major automated one, used to attack Enigma-enciphered messages.
The bombe searched for possible correct settings used for an Enigma message (i.e., rotor order, rotor settings and plugboard settings) using a suitable '' crib'': a fragment of probable plaintext
In cryptography, plaintext usually means unencrypted information pending input into cryptographic algorithms, usually encryption algorithms. This usually refers to data that is transmitted or stored unencrypted.
Overview
With the advent of com ...
. For each possible setting of the rotors (which had on the order of 1019 states, or 1022 states for the four-rotor U-boat variant), the bombe performed a chain of logical deductions based on the crib, implemented electromechanically.
The bombe detected when a contradiction had occurred and ruled out that setting, moving on to the next. Most of the possible settings would cause contradictions and be discarded, leaving only a few to be investigated in detail. A contradiction would occur when an enciphered letter would be turned back into the same plaintext letter, which was impossible with the Enigma. The first bombe was installed on 18 March 1940.
Action This Day
By late 1941, Turing and his fellow cryptanalysts Gordon Welchman
William Gordon Welchman (15 June 1906 – 8 October 1985) was a British mathematician. During World War II, he worked at Britain's secret codebreaking centre, "Station X" at Bletchley Park, where he was one of the most important contributors. ...
, Hugh Alexander and Stuart Milner-Barry
Sir Philip Stuart Milner-Barry (20 September 1906 – 25 March 1995) was a British chess player, chess writer, World War II codebreaker and civil servant. He represented England in chess both before and after World War II. He worked at Bletch ...
were frustrated. Building on the work of the Poles, they had set up a good working system for decrypting Enigma signals, but their limited staff and bombes meant they could not translate all the signals. In the summer, they had considerable success, and shipping losses had fallen to under 100,000 tons a month; however, they badly needed more resources to keep abreast of German adjustments. They had tried to get more people and fund more bombes through the proper channels, but had failed.
On 28 October they wrote directly to Winston Churchill
Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 Winston Churchill in the Second World War, dur ...
explaining their difficulties, with Turing as the first named. They emphasised how small their need was compared with the vast expenditure of men and money by the forces and compared with the level of assistance they could offer to the forces. As Andrew Hodges
Andrew Philip Hodges (; born 1949) is a British mathematician, author and emeritus senior research fellow at Wadham College, Oxford.
Education
Hodges was born in London in 1949 and educated at Birkbeck, University of London where he was award ...
, biographer of Turing, later wrote, "This letter had an electric effect." Churchill wrote a memo to General Ismay, which read: "ACTION THIS DAY. Make sure they have all they want on extreme priority and report to me that this has been done." On 18 November, the chief of the secret service reported that every possible measure was being taken. The cryptographers at Bletchley Park did not know of the Prime Minister's response, but as Milner-Barry recalled, "All that we did notice was that almost from that day the rough ways began miraculously to be made smooth." More than two hundred bombes were in operation by the end of the war.
Hut 8 and the naval Enigma
Turing decided to tackle the particularly difficult problem of German naval Enigma "because no one else was doing anything about it and I could have it to myself". In December 1939, Turing solved the essential part of the naval indicator
Indicator may refer to:
Biology
* Environmental indicator of environmental health (pressures, conditions and responses)
* Ecological indicator of ecosystem health (ecological processes)
* Health indicator, which is used to describe the health ...
system, which was more complex than the indicator systems used by the other services.
That same night, he also conceived of the idea of ''Banburismus
Banburismus was a cryptanalytic process developed by Alan Turing at Bletchley Park in Britain during the Second World War. It was used by Bletchley Park's Hut 8 to help break German ''Kriegsmarine'' (naval) messages enciphered on Enigma machin ...
'', a sequential statistical technique (what Abraham Wald
Abraham Wald (; hu, Wald Ábrahám, yi, אברהם וואַלד; – ) was a Jewish Hungarian mathematician who contributed to decision theory, geometry, and econometrics and founded the field of statistical sequential analysis. One ...
later called sequential analysis
In statistics, sequential analysis or sequential hypothesis testing is statistical analysis where the sample size is not fixed in advance. Instead data are evaluated as they are collected, and further sampling is stopped in accordance with a pre- ...
) to assist in breaking the naval Enigma, "though I was not sure that it would work in practice, and was not, in fact, sure until some days had actually broken." For this, he invented a measure of weight of evidence that he called the '' ban''. ''Banburismus'' could rule out certain sequences of the Enigma rotors, substantially reducing the time needed to test settings on the bombes. Later this sequential process of accumulating sufficient weight of evidence using decibans (one tenth of a ban) was used in Cryptanalysis of the Lorenz cipher
Cryptanalysis of the Lorenz cipher was the process that enabled the British to read high-level German army messages during World War II. The British Government Code and Cypher School (GC&CS) at Bletchley Park decrypted many communications betwee ...
.
Turing travelled to the United States in November 1942 and worked with US Navy cryptanalysts on the naval Enigma and bombe construction in Washington; he also visited their Computing Machine Laboratory
The Computing Machine Laboratory at the University of Manchester in the north of England was established by Max Newman shortly after the end of World War II, around 1946.
The Laboratory was funded through a grant from the Royal Society, which was ...
in Dayton, Ohio
Dayton () is the sixth-largest city in the U.S. state of Ohio and the county seat of Montgomery County. A small part of the city extends into Greene County. The 2020 U.S. census estimate put the city population at 137,644, while Greater Day ...
.
Turing's reaction to the American bombe design was far from enthusiastic:
During this trip, he also assisted at Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial Research and development, research and scientific developm ...
with the development of secure speech devices. He returned to Bletchley Park in March 1943. During his absence, Hugh Alexander had officially assumed the position of head of Hut 8, although Alexander had been ''de facto'' head for some time (Turing having little interest in the day-to-day running of the section). Turing became a general consultant for cryptanalysis at Bletchley Park.
Alexander wrote of Turing's contribution:
Turingery
In July 1942, Turing devised a technique termed ''Turingery
Turingery in ''Testery Methods 1942–1944'' or Turing's method (playfully dubbed Turingismus by Peter Ericsson, Peter Hilton and Donald Michie) was a manual codebreaking method devised in July 1942 by the mathematician and cryptanalyst Alan Turi ...
'' (or jokingly ''Turingismus'') for use against the Lorenz cipher
The Lorenz SZ40, SZ42a and SZ42b were German rotor stream cipher machines used by the German Army during World War II. They were developed by C. Lorenz AG in Berlin. The model name ''SZ'' was derived from ''Schlüssel-Zusatz'', meaning ''cipher ...
messages produced by the Germans' new ''Geheimschreiber'' (secret writer) machine. This was a teleprinter
A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Init ...
rotor cipher attachment codenamed ''Tunny'' at Bletchley Park. Turingery was a method of ''wheel-breaking'', i.e., a procedure for working out the cam settings of Tunny's wheels. He also introduced the Tunny team to Tommy Flowers
Thomas Harold Flowers MBE (22 December 1905 – 28 October 1998) was an English engineer with the British General Post Office. During World War II, Flowers designed and built Colossus, the world's first programmable electronic computer, to help ...
who, under the guidance of Max Newman
Maxwell Herman Alexander Newman, FRS, (7 February 1897 – 22 February 1984), generally known as Max Newman, was a British mathematician and codebreaker. His work in World War II led to the construction of Colossus, the world's first operatio ...
, went on to build the Colossus computer
Colossus was a set of computers developed by British codebreakers in the years 1943–1945 to help in the cryptanalysis of the Lorenz cipher. Colossus used thermionic valves (vacuum tubes) to perform Boolean and counting operations. Colossus ...
, the world's first programmable digital electronic computer, which replaced a simpler prior machine (the Heath Robinson
William Heath Robinson (31 May 1872 – 13 September 1944) was an English cartoonist, illustrator and artist, best known for drawings of whimsically elaborate machines to achieve simple objectives.
In the UK, the term "Heath Robinson cont ...
), and whose superior speed allowed the statistical decryption techniques to be applied usefully to the messages. Some have mistakenly said that Turing was a key figure in the design of the Colossus computer. Turingery and the statistical approach of Banburismus undoubtedly fed into the thinking about cryptanalysis of the Lorenz cipher
Cryptanalysis of the Lorenz cipher was the process that enabled the British to read high-level German army messages during World War II. The British Government Code and Cypher School (GC&CS) at Bletchley Park decrypted many communications betwee ...
, but he was not directly involved in the Colossus development.
Delilah
Following his work at Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial Research and development, research and scientific developm ...
in the US, Turing pursued the idea of electronic enciphering of speech in the telephone system. In the latter part of the war, he moved to work for the Secret Service's Radio Security Service (later HMGCC) at Hanslope Park
Hanslope Park is located about half a mile south-east of the village of Hanslope in the City of Milton Keynes, Buckinghamshire, England. Once the manorial estate of the village, it is now owned by the UK Foreign, Commonwealth and Development Of ...
. At the park, he further developed his knowledge of electronics with the assistance of engineer Donald Bayley. Together they undertook the design and construction of a portable secure voice
Secure voice (alternatively secure speech or ciphony) is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.
History
The implementation of voice encryption dat ...
communications machine codenamed ''Delilah
Delilah ( ; , meaning "delicate";Gesenius's ''Hebrew-Chaldee Lexicon'' ar, دليلة, Dalīlah; grc, label= Greek, Δαλιδά, Dalidá) is a woman mentioned in the sixteenth chapter of the Book of Judges in the Hebrew Bible. She is loved ...
''. The machine was intended for different applications, but it lacked the capability for use with long-distance radio transmissions. In any case, Delilah was completed too late to be used during the war. Though the system worked fully, with Turing demonstrating it to officials by encrypting and decrypting a recording of a Winston Churchill
Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 Winston Churchill in the Second World War, dur ...
speech, Delilah was not adopted for use. Turing also consulted with Bell Labs on the development of SIGSALY
SIGSALY (also known as the X System, Project X, Ciphony I, and the Green Hornet) was a secure speech system used in World War II for the highest-level Allied communications. It pioneered a number of digital communications concepts, including the ...
, a secure voice system that was used in the later years of the war.
Early computers and the Turing test
Between 1945 and 1947, Turing lived in Hampton
Hampton may refer to:
Places Australia
*Hampton bioregion, an IBRA biogeographic region in Western Australia
*Hampton, New South Wales
*Hampton, Queensland, a town in the Toowoomba Region
* Hampton, Victoria
Canada
* Hampton, New Brunswick
*Ha ...
, London, while he worked on the design of the ACE
An ace is a playing card, die or domino with a single pip. In the standard French deck, an ace has a single suit symbol (a heart, diamond, spade, or club) located in the middle of the card, sometimes large and decorated, especially in the c ...
(Automatic Computing Engine) at the National Physical Laboratory (NPL). He presented a paper on 19 February 1946, which was the first detailed design of a stored-program computer. Von Neumann Von Neumann may refer to:
* John von Neumann (1903–1957), a Hungarian American mathematician
* Von Neumann family
* Von Neumann (surname), a German surname
* Von Neumann (crater), a lunar impact crater
See also
* Von Neumann algebra
* Von Ne ...
's incomplete ''First Draft of a Report on the EDVAC
The ''First Draft of a Report on the EDVAC'' (commonly shortened to ''First Draft'') is an incomplete 101-page document written by John von Neumann and distributed on June 30, 1945 by Herman Goldstine, security officer on the classified ENIAC pro ...
'' had predated Turing's paper, but it was much less detailed and, according to John R. Womersley
John Ronald Womersley (20 June 1907 – 7 March 1958) was a British mathematician and computer scientist who made important contributions to computer development, and hemodynamics. Nowadays he is principally remembered for his contribution ...
, Superintendent of the NPL Mathematics Division, it "contains a number of ideas which are Dr. Turing's own".
Although ACE was a feasible design, the effect of the Official Secrets Act surrounding the wartime work at Bletchley Park made it impossible for Turing to explain the basis of his analysis of how a computer installation involving human operators would work. This led to delays in starting the project and he became disillusioned. In late 1947 he returned to Cambridge for a sabbatical year during which he produced a seminal work on ''Intelligent Machinery'' that was not published in his lifetime. While he was at Cambridge, the Pilot ACE
The Pilot ACE (Automatic Computing Engine) was one of the first computers built in the United Kingdom. Built at the National Physical Laboratory (NPL) in the early 1950s, it was also one of the earliest general-purpose, stored-program computers ...
was being built in his absence. It executed its first program on 10 May 1950, and a number of later computers around the world owe much to it, including the English Electric DEUCE
The DEUCE (''Digital Electronic Universal Computing Engine'') was one of the earliest British commercially available computers, built by English Electric from 1955. It was the production version of the Pilot ACE, itself a cut-down version of ...
and the American Bendix G-15
The Bendix G-15 is a computer introduced in 1956 by the Bendix Corporation, Computer Division, Los Angeles, California. It is about and weighs about . The G-15 has a drum memory of 2,160 29-bit words, along with 20 words used for special purpos ...
. The full version of Turing's ACE was not built until after his death.
According to the memoirs of the German computer pioneer Heinz Billing
Heinz Billing (7 April 1914 – 4 January 2017) was a German physicist and computer scientist, widely considered a pioneer in the construction of computer systems and computer data storage, who built a prototype laser interferometric gravitation ...
from the Max Planck Institute for Physics
The Max Planck Institute for Physics (MPP) is a physics institute in Munich, Germany that specializes in high energy physics and astroparticle physics. It is part of the Max-Planck-Gesellschaft and is also known as the Werner Heisenberg Institu ...
, published by Genscher, Düsseldorf, there was a meeting between Turing and Konrad Zuse
Konrad Ernst Otto Zuse (; 22 June 1910 – 18 December 1995) was a German civil engineer, pioneering computer scientist, inventor and businessman. His greatest achievement was the world's first programmable computer; the functional program ...
. It took place in Göttingen
Göttingen (, , ; nds, Chöttingen) is a university city in Lower Saxony, central Germany, the capital of the eponymous district. The River Leine runs through it. At the end of 2019, the population was 118,911.
General information
The ori ...
in 1947. The interrogation had the form of a colloquium. Participants were Womersley, Turing, Porter from England and a few German researchers like Zuse, Walther, and Billing (for more details see Herbert Bruderer, ''Konrad Zuse und die Schweiz'').
In 1948, Turing was appointed reader
A reader is a person who reads. It may also refer to:
Computing and technology
* Adobe Reader (now Adobe Acrobat), a PDF reader
* Bible Reader for Palm, a discontinued PDA application
* A card reader, for extracting data from various forms of ...
in the Mathematics Department at the Victoria University of Manchester
The Victoria University of Manchester, usually referred to as simply the University of Manchester, was a university in Manchester, England. It was founded in 1851 as Owens College. In 1880, the college joined the federal Victoria University. Afte ...
. A year later, he became deputy director of the Computing Machine Laboratory, where he worked on software for one of the earliest stored-program computers—the Manchester Mark 1
The Manchester Mark 1 was one of the earliest stored-program computers, developed at the Victoria University of Manchester, England from the Manchester Baby (operational in June 1948). Work began in August 1948, and the first version was oper ...
. Turing wrote the first version of the Programmer's Manual for this machine, and was recruited by Ferranti as a consultant in the development of their commercialised machine, the Ferranti Mark 1. He continued to be paid consultancy fees by Ferranti until his death. During this time, he continued to do more abstract work in mathematics, and in "Computing Machinery and Intelligence
"Computing Machinery and Intelligence" is a seminal paper written by Alan Turing on the topic of artificial intelligence. The paper, published in 1950 in ''Mind'', was the first to introduce his concept of what is now known as the Turing test to ...
" ('' Mind'', October 1950), Turing addressed the problem of artificial intelligence
Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech r ...
, and proposed an experiment that became known as the Turing test
The Turing test, originally called the imitation game by Alan Turing in 1950, is a test of a machine's ability to exhibit intelligent behaviour equivalent to, or indistinguishable from, that of a human. Turing proposed that a human evaluato ...
, an attempt to define a standard for a machine to be called "intelligent". The idea was that a computer could be said to "think" if a human interrogator could not tell it apart, through conversation, from a human being. In the paper, Turing suggested that rather than building a program to simulate the adult mind, it would be better to produce a simpler one to simulate a child's mind and then to subject it to a course of education. A reversed form of the Turing test is widely used on the Internet; the CAPTCHA
A CAPTCHA ( , a contrived acronym for "Completely Automated Public Turing test to tell Computers and Humans Apart") is a type of challenge–response test used in computing to determine whether the user is human.
The term was coined in 2003 b ...
test is intended to determine whether the user is a human or a computer.
In 1948, Turing, working with his former undergraduate colleague, D.G. Champernowne, began writing a chess
Chess is a board game for two players, called White and Black, each controlling an army of chess pieces in their color, with the objective to checkmate the opponent's king. It is sometimes called international chess or Western chess to disti ...
program for a computer that did not yet exist. By 1950, the program was completed and dubbed the Turochamp. In 1952, he tried to implement it on a Ferranti Mark 1
The Ferranti Mark 1, also known as the Manchester Electronic Computer in its sales literature, and thus sometimes called the Manchester Ferranti, was produced by British electrical engineering firm Ferranti Ltd. It was the world's first commer ...
, but lacking enough power, the computer was unable to execute the program. Instead, Turing "ran" the program by flipping through the pages of the algorithm and carrying out its instructions on a chessboard, taking about half an hour per move. The game was recorded. According to Garry Kasparov
Garry Kimovich Kasparov (born 13 April 1963) is a Russian chess grandmaster, former World Chess Champion, writer, political activist and commentator. His peak rating of 2851, achieved in 1999, was the highest recorded until being surpassed by ...
, Turing's program "played a recognizable game of chess." The program lost to Turing's colleague Alick Glennie
Alick Edwards Glennie (1925–2003) was a British computer scientist, most famous for having developed Autocode, which many people regard as the first ever computer compiler.Knuth, Donald E.; Pardo, Luis Trabb, "Early development of programming ...
, although it is said that it won a game against Champernowne's wife,
Isabel.
His Turing test was a significant, characteristically provocative, and lasting contribution to the debate regarding artificial intelligence, which continues after more than half a century.
Pattern formation and mathematical biology
When Turing was 39 years old in 1951, he turned to mathematical biology, finally publishing his masterpiece "The Chemical Basis of Morphogenesis
"The Chemical Basis of Morphogenesis" is an article that the English mathematician Alan Turing wrote in 1952. It describes how patterns in nature, such as stripes and spirals, can arise naturally from a homogeneous, uniform state. The theory, w ...
" in January 1952. He was interested in morphogenesis
Morphogenesis (from the Greek ''morphê'' shape and ''genesis'' creation, literally "the generation of form") is the biological process that causes a cell, tissue or organism to develop its shape. It is one of three fundamental aspects of deve ...
, the development of patterns and shapes in biological organisms. He suggested that a system of chemicals reacting with each other and diffusing across space, termed a reaction–diffusion system
Reaction–diffusion systems are mathematical models which correspond to several physical phenomena. The most common is the change in space and time of the concentration of one or more chemical substances: local chemical reactions in which the s ...
, could account for "the main phenomena of morphogenesis". He used systems of partial differential equations
In mathematics, a partial differential equation (PDE) is an equation which imposes relations between the various partial derivatives of a multivariable function.
The function is often thought of as an "unknown" to be solved for, similarly to ...
to model catalytic chemical reactions. For example, if a catalyst A is required for a certain chemical reaction to take place, and if the reaction produced more of the catalyst A, then we say that the reaction is autocatalytic
A single chemical reaction is said to be autocatalytic if one of the reaction products is also a catalyst for the same or a coupled reaction.Steinfeld J.I., Francisco J.S. and Hase W.L. ''Chemical Kinetics and Dynamics'' (2nd ed., Prentice-Hall 199 ...
, and there is positive feedback that can be modelled by nonlinear differential equations. Turing discovered that patterns could be created if the chemical reaction not only produced catalyst A, but also produced an inhibitor B that slowed down the production of A. If A and B then diffused through the container at different rates, then you could have some regions where A dominated and some where B did. To calculate the extent of this, Turing would have needed a powerful computer, but these were not so freely available in 1951, so he had to use linear approximations to solve the equations by hand. These calculations gave the right qualitative results, and produced, for example, a uniform mixture that oddly enough had regularly spaced fixed red spots. The Russian biochemist Boris Belousov had performed experiments with similar results, but could not get his papers published because of the contemporary prejudice that any such thing violated the second law of thermodynamics
The second law of thermodynamics is a physical law based on universal experience concerning heat and energy interconversions. One simple statement of the law is that heat always moves from hotter objects to colder objects (or "downhill"), unles ...
. Belousov was not aware of Turing's paper in the ''Philosophical Transactions of the Royal Society
''Philosophical Transactions of the Royal Society'' is a scientific journal published by the Royal Society. In its earliest days, it was a private venture of the Royal Society's secretary. It was established in 1665, making it the first journa ...
''.
Although published before the structure and role of DNA was understood, Turing's work on morphogenesis remains relevant today and is considered a seminal piece of work in mathematical biology. One of the early applications of Turing's paper was the work by James Murray explaining spots and stripes on the fur of cats, large and small. Further research in the area suggests that Turing's work can partially explain the growth of "feathers, hair follicles, the branching pattern of lungs, and even the left-right asymmetry that puts the heart on the left side of the chest." In 2012, Sheth, et al. found that in mice, removal of Hox genes
Hox genes, a subset of homeobox genes, are a group of related genes that specify regions of the body plan of an embryo along the head-tail axis of animals. Hox proteins encode and specify the characteristics of 'position', ensuring that the co ...
causes an increase in the number of digits without an increase in the overall size of the limb, suggesting that Hox genes control digit formation by tuning the wavelength of a Turing-type mechanism. Later papers were not available until ''Collected Works of A. M. Turing'' was published in 1992.
Personal life
Engagement
In 1941, Turing proposed marriage to Hut 8 colleague Joan Clarke
Joan Elisabeth Lowther Murray, MBE (''née'' Clarke; 24 June 1917 – 4 September 1996) was an English cryptanalyst and numismatist best known for her work as a code-breaker at Bletchley Park during the Second World War. Although she did not ...
, a fellow mathematician and cryptanalyst, but their engagement was short-lived. After admitting his homosexuality to his fiancée, who was reportedly "unfazed" by the revelation, Turing decided that he could not go through with the marriage.
Homosexuality and indecency conviction
In January 1952, Turing was 39 when he started a relationship with Arnold Murray, a 19-year-old unemployed man. Just before Christmas, Turing was walking along Manchester's Oxford Road when he met Murray just outside the Regal Cinema
The Regal Cinema is an Art deco movie theatre located at Colaba Causeway, in Mumbai, India. Built by Framji Sidhwa, the first film to be aired at the Regal was the Laurel and Hardy work '' The Devil's Brother'' in 1933.
According to the '' ...
and invited him to lunch. On 23 January, Turing's house was burgled. Murray told Turing that he and the burglar were acquainted, and Turing reported the crime to the police. During the investigation, he acknowledged a sexual relationship with Murray. Homosexual acts were criminal offences in the United Kingdom at that time, and both men were charged with " gross indecency" under Section 11 of the Criminal Law Amendment Act 1885
The Criminal Law Amendment Act 1885 ( 48 & 49 Vict. c.69), or "An Act to make further provision for the Protection of Women and Girls, the suppression of brothels, and other purposes," was an Act of the Parliament of the United Kingdom, the lat ...
. Initial committal proceedings for the trial were held on 27 February during which Turing's solicitor "reserved his defence", i.e., did not argue or provide evidence against the allegations.
Turing was later convinced by the advice of his brother and his own solicitor, and he entered a plea of guilty. The case, '' Regina v. Turing and Murray,'' was brought to trial on 31 March 1952. Turing was convicted and given a choice between imprisonment and probation. His probation would be conditional on his agreement to undergo hormonal
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required f ...
physical changes designed to reduce libido
Libido (; colloquial: sex drive) is a person's overall sexual drive or desire for sexual activity. Libido is influenced by biological, psychological, and social factors. Biologically, the sex hormones and associated neurotransmitters that act u ...
, known as "chemical castration." He accepted the option of injections of what was then called stilboestrol (now known as diethylstilbestrol
Diethylstilbestrol (DES), also known as stilbestrol or stilboestrol, is a nonsteroidal estrogen medication, which is presently rarely used. In the past, it was widely used for a variety of indications, including pregnancy support for those with a ...
or DES), a synthetic oestrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal acti ...
; this feminization of his body was continued for the course of one year. The treatment rendered Turing impotent
Erectile dysfunction (ED), also called impotence, is the type of sexual dysfunction in which the penis fails to become or stay erect during sexual activity. It is the most common sexual problem in men.Cunningham GR, Rosen RC. Overview of mal ...
and caused breast tissue to form, fulfilling in the literal sense Turing's prediction that "no doubt I shall emerge from it all a different man, but quite who I've not found out". Murray was given a conditional discharge.
Turing's conviction led to the removal of his security clearance and barred him from continuing with his cryptographic consultancy for the Government Communications Headquarters
Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Un ...
(GCHQ), the British signals intelligence agency that had evolved from GC&CS in 1946, though he kept his academic job. He was denied entry into the United States after his conviction in 1952, but was free to visit other European countries.
Treasure
In the 1940s, Turing became worried about losing his savings in the event of a German invasion. In order to protect it, he bought two silver bars weighing and worth £250 (in 2022, £8,000 adjusted for inflation, £48,000 at spot price) and buried them in a wood near Bletchley Park. Upon returning to dig them up, Turing found that he was unable to break his own code describing where exactly he had hidden them. This, along with the fact that the area had been renovated, meant that he never regained the silver.
Death
On 8 June 1954, at his house at 43 Adlington Road, Wilmslow
Wilmslow ( ) is a market town and civil parish in the unitary authority of Cheshire East in Cheshire, England, south of Manchester city centre. The population was 24,497 at the 2011 Census.
History
Toponymy
Wilmslow derives its name from Old ...
, Turing's housekeeper found him dead. He had died the previous day at the age of 41. Cyanide poisoning
Cyanide poisoning is poisoning that results from exposure to any of a number of forms of cyanide. Early symptoms include headache, dizziness, fast heart rate, shortness of breath, and vomiting. This phase may then be followed by seizures, sl ...
was established as the cause of death. When his body was discovered, an apple lay half-eaten beside his bed, and although the apple was not tested for cyanide, it was speculated that this was the means by which Turing had consumed a fatal dose. An inquest determined that he had committed suicide. Andrew Hodges and another biographer, David Leavitt
David Leavitt (; born June 23, 1961) is an American novelist, short story writer, and biographer.
Biography
Leavitt was born in Pittsburgh, Pennsylvania to Harold and Gloria Leavitt. Harold was a professor who taught at Stanford University and G ...
, have both speculated that Turing was re-enacting a scene from the Walt Disney
Walter Elias Disney (; December 5, 1901December 15, 1966) was an American animator, film producer and entrepreneur. A pioneer of the American animation industry, he introduced several developments in the production of cartoons. As a film p ...
film ''Snow White and the Seven Dwarfs
"Snow White and the Seven Dwarfs" is a 19th-century German fairy tale that is today known widely across the Western world. The Brothers Grimm published it in 1812 in the first edition of their collection ''Grimms' Fairy Tales'' and numbered as T ...
'' (1937), his favourite fairy tale. Both men noted that (in Leavitt's words) he took "an especially keen pleasure in the scene where the Wicked Queen immerses her apple in the poisonous brew". Turing's remains were cremated at Woking Crematorium
Woking Crematorium is a crematorium in Woking, a large town in the west of Surrey, England. Established in 1878, it was the first custom-built crematorium in the United Kingdom and is closely linked to the history of cremation in the UK.
Loc ...
on 12 June 1954, and his ashes were scattered in the gardens of the crematorium, just as his father's had been.
Philosopher Jack Copeland
Brian John Copeland (born 1950) is Professor of Philosophy at the University of Canterbury, Christchurch, New Zealand, and author of books on the computing pioneer Alan Turing.
Education
Copeland was educated at the University of Oxford, obta ...
has questioned various aspects of the coroner's historical verdict. He suggested an alternative explanation for the cause of Turing's death: the accidental inhalation of cyanide fumes from an apparatus used to electroplate
Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the reduction of cations of that metal by means of a direct electric current. The part to be ...
gold onto spoons. The potassium cyanide was used to dissolve the gold. Turing had such an apparatus set up in his tiny spare room. Copeland noted that the autopsy findings were more consistent with inhalation than with ingestion of the poison. Turing also habitually ate an apple before going to bed, and it was not unusual for the apple to be discarded half-eaten. Furthermore, Turing had reportedly borne his legal setbacks and hormone treatment (which had been discontinued a year previously) "with good humour" and had shown no sign of despondency before his death. He even set down a list of tasks that he intended to complete upon returning to his office after the holiday weekend. Turing's mother believed that the ingestion was accidental, resulting from her son's careless storage of laboratory chemicals. Biographer Andrew Hodges theorised that Turing arranged the delivery of the equipment to deliberately allow his mother plausible deniability with regard to any suicide claims.
It has been suggested that Turing's belief in fortune-telling
Fortune telling is the practice of predicting information about a person's life. Melton, J. Gordon. (2008). ''The Encyclopedia of Religious Phenomena''. Visible Ink Press. pp. 115-116. The scope of fortune telling is in principle identical wi ...
may have caused his depressed mood. As a youth, Turing had been told by a fortune-teller that he would be a genius. In mid-May 1954, shortly before his death, Turing again decided to consult a fortune-teller during a day-trip to St Annes-on-Sea with the Greenbaum family. According to the Greenbaums' daughter, Barbara:
Government apology and pardon
In August 2009, British programmer John Graham-Cumming
John Graham-Cumming is a British software engineer and writer best known for starting a successful petition to the Government of the United Kingdom asking for an apology for its persecution of Alan Turing. , he serves as Chief Technology Officer ...
started a petition urging the British government to apologise for Turing's prosecution as a homosexual. The petition received more than 30,000 signatures. The Prime Minister, Gordon Brown
James Gordon Brown (born 20 February 1951) is a British former politician who served as Prime Minister of the United Kingdom and Leader of the Labour Party from 2007 to 2010. He previously served as Chancellor of the Exchequer in Tony B ...
, acknowledged the petition, releasing a statement on 10 September 2009 apologising and describing the treatment of Turing as "appalling":
In December 2011, William Jones and his Member of Parliament, John Leech, created an e-petition requesting that the British government pardon Turing for his conviction of "gross indecency":
The petition gathered over 37,000 signatures, and was submitted to Parliament by the Manchester MP John Leech but the request was discouraged by Justice Minister Lord McNally
Thomas McNally, Baron McNally, PC (born 20 February 1943) is a British politician and a former Leader of the Liberal Democrats in the House of Lords.
Early life
McNally was born in Blackpool. A Catholic of Irish descent, he attended St J ...
, who said:
John Leech, the MP for Manchester Withington
Manchester Withington is a constituency represented in the House of Commons of the UK Parliament since 2015 by Jeff Smith of Labour. Of the 30 seats with the highest percentage of winning majority in 2017, the seat ranks 25th with a 55.7% ma ...
(2005–15), submitted several bills to Parliament and led a high-profile campaign to secure the pardon. Leech made the case in the House of Commons that Turing's contribution to the war made him a national hero and that it was "ultimately just embarrassing" that the conviction still stood. Leech continued to take the bill through Parliament and campaigned for several years, gaining the public support of numerous leading scientists, including Stephen Hawking. At the British premiere of a film based on Turing's life, ''The Imitation Game
''The Imitation Game'' is a 2014 American historical drama film directed by Morten Tyldum and written by Graham Moore, based on the 1983 biography '' Alan Turing: The Enigma'' by Andrew Hodges. The film's title quotes the name of the game c ...
'', the producers thanked Leech for bringing the topic to public attention and securing Turing's pardon. Leech is now regularly described as the "architect" of Turing's pardon and subsequently the Alan Turing Law which went on to secure pardons for 75,000 other men and women convicted of similar crimes.
On 26 July 2012, a bill was introduced in the House of Lords
The House of Lords, also known as the House of Peers, is the Bicameralism, upper house of the Parliament of the United Kingdom. Membership is by Life peer, appointment, Hereditary peer, heredity or Lords Spiritual, official function. Like the ...
to grant a statutory pardon to Turing for offences under section 11 of the Criminal Law Amendment Act 1885, of which he was convicted on 31 March 1952. Late in the year in a letter to ''The Daily Telegraph
''The Daily Telegraph'', known online and elsewhere as ''The Telegraph'', is a national British daily broadsheet newspaper published in London by Telegraph Media Group and distributed across the United Kingdom and internationally.
It was fo ...
'', the physicist Stephen Hawking and 10 other signatories including the Astronomer Royal
Astronomer Royal is a senior post in the Royal Households of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675; the junior is the Astronomer Royal for Scotland dating from 1834.
The post ...
Lord Rees, President of the Royal Society
The president of the Royal Society (PRS) is the elected Head of the Royal Society of London who presides over meetings of the society's council.
After informal meetings at Gresham College, the Royal Society was officially founded on 28 November ...
Sir Paul Nurse
Sir Paul Maxime Nurse (born 25 January 1949) is an English geneticist, former President of the Royal Society and Chief Executive and Director of the Francis Crick Institute. He was awarded the 2001 Nobel Prize in Physiology or Medicine along ...
, Lady Trumpington (who worked for Turing during the war) and Lord Sharkey (the bill's sponsor) called on Prime Minister David Cameron to act on the pardon request. The government indicated it would support the bill, and it passed its third reading in the House of Lords in October.
At the bill's second reading in the House of Commons
The House of Commons is the name for the elected lower house of the bicameral parliaments of the United Kingdom and Canada. In both of these countries, the Commons holds much more legislative power than the nominally upper house of parliament. ...
on 29 November 2013, Conservative MP Christopher Chope
Sir Christopher Robert Chope (born 19 May 1947) is a British barrister and politician who has served as the Member of Parliament (MP) for Christchurch in Dorset since 1997. A member of the Conservative Party, he was first elected in 1983 fo ...
objected to the bill, delaying its passage. The bill was due to return to the House of Commons on 28 February 2014, but before the bill could be debated in the House of Commons, the government elected to proceed under the royal prerogative of mercy
In the English and British tradition, the royal prerogative of mercy is one of the historic royal prerogatives of the British monarch, by which they can grant pardons (informally known as a royal pardon) to convicted persons. The royal prer ...
. On 24 December 2013, Queen Elizabeth II
Elizabeth II (Elizabeth Alexandra Mary; 21 April 1926 – 8 September 2022) was Queen of the United Kingdom and other Commonwealth realms from 6 February 1952 until Death and state funeral of Elizabeth II, her death in 2022. She was queen ...
signed a pardon for Turing's conviction for "gross indecency", with immediate effect. Announcing the pardon, Lord Chancellor Chris Grayling
Christopher Stephen Grayling (born 1 April 1962) is a British Conservative Party politician and author who served as Secretary of State for Transport from 2016 to 2019. He has served as Member of Parliament (MP) for Epsom and Ewell since 2001. ...
said Turing deserved to be "remembered and recognised for his fantastic contribution to the war effort" and not for his later criminal conviction. The Queen officially pronounced Turing pardoned in August 2014. The Queen's action is only the fourth royal pardon granted since the conclusion of the Second World War. Pardons are normally granted only when the person is technically innocent, and a request has been made by the family or other interested party; neither condition was met in regard to Turing's conviction.
In September 2016, the government announced its intention to expand this retroactive exoneration to other men convicted of similar historical indecency offences, in what was described as an " Alan Turing law". The Alan Turing law is now an informal term for the law in the United Kingdom, contained in the Policing and Crime Act 2017
The Policing and Crime Act 2017 (c. 3) is an act of the Parliament of the United Kingdom. It received royal assent on 31 January 2017.
Synopsis
The act enacts various changes to existing rules involving PCCs, complaints through the IPCC, amendm ...
, which serves as an amnesty law
An Amnesty law is any legislative, constitutional or executive arrangement that retroactively exempts a select group of people, usually military leaders and government leaders, from criminal liability for the crimes that they committed. More speci ...
to retroactively pardon men who were cautioned or convicted under historical legislation that outlawed homosexual acts. The law applies in England and Wales.
Legacy
Awards, honours, and tributes
Turing was appointed an officer of the Order of the British Empire
The Most Excellent Order of the British Empire is a British order of chivalry, rewarding contributions to the arts and sciences, work with charitable and welfare organisations,
and public service outside the civil service. It was established ...
in 1946. He was also elected a Fellow of the Royal Society (FRS) in 1951.
Turing has been honoured in various ways in Manchester
Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
, the city where he worked towards the end of his life. In 1994, a stretch of the A6010 road
List of A roads in zone 6 in Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island ...
(the Manchester
Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...
city intermediate ring road) was named "Alan Turing Way". A bridge carrying this road was widened, and carries the name Alan Turing Bridge. A statue of Turing was unveiled in Manchester on 23 June 2001 in Sackville Park, between the University of Manchester building on Whitworth Street and Canal Street. The memorial statue depicts the "father of computer science" sitting on a bench at a central position in the park. Turing is shown holding an apple. The cast bronze bench carries in relief the text 'Alan Mathison Turing 1912–1954', and the motto 'Founder of Computer Science' as it could appear if encoded by an Enigma machine: 'IEKYF ROMSI ADXUO KVKZC GUBJ'. However, the meaning of the coded message is disputed, as the 'u' in 'computer' matches up with the 'u' in 'ADXUO'. As a letter encoded by an enigma machine cannot appear as itself, the actual message behind the code is uncertain.
A plaque at the statue's feet reads 'Father of computer science, mathematician, logician, wartime codebreaker, victim of prejudice'. There is also a Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British mathematician, philosopher, logician, and public intellectual. He had a considerable influence on mathematics, logic, set theory, linguistics, ...
quotation: "Mathematics, rightly viewed, possesses not only truth, but supreme beauty—a beauty cold and austere, like that of sculpture." The sculptor buried his own old Amstrad
Amstrad was a British electronics company, founded in 1968 by Alan Sugar at the age of 21. The name is a contraction of Alan Michael Sugar Trading. It was first listed on the London Stock Exchange in April 1980. During the late 1980s, Amstra ...
computer under the plinth
A pedestal (from French ''piédestal'', Italian ''piedistallo'' 'foot of a stall') or plinth is a support at the bottom of a statue, vase, column, or certain altars. Smaller pedestals, especially if round in shape, may be called socles. In ...
as a tribute to "the godfather of all modern computers".
In 1999, ''Time
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, into the future. It is a component quantity of various measurements used to sequence events, to ...
'' magazine named Turing as one of the 100 Most Important People of the 20th century and stated, "The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine."
A blue plaque was unveiled at King's College, Cambridge on the centenary of his birth on 23 June 2012 and is now installed at the college's Keynes Building on King's Parade. A high steel sculpture, designed in Turing's honour by Sir Antony Gormley, is planned to be installed at King's College, but Historic England
Historic England (officially the Historic Buildings and Monuments Commission for England) is an executive non-departmental public body of the British Government sponsored by the Department for Digital, Culture, Media and Sport. It is tasked w ...
deemed the sculpture too abstract for the setting, saying that it "would result in harm, of a less than substantial nature, to the significance of the listed building
In the United Kingdom, a listed building or listed structure is one that has been placed on one of the four statutory lists maintained by Historic England in England, Historic Environment Scotland in Scotland, in Wales, and the Northern Irel ...
s and landscape, and by extension the conservation area."
On 25 March 2021, the Bank of England
The Bank of England is the central bank of the United Kingdom and the model on which most modern central banks have been based. Established in 1694 to act as the English Government's banker, and still one of the bankers for the Government of ...
publicly unveiled the design for a new £50 note, featuring Turing's portrait, before its official issue on 23 June, Turing's birthday. Turing was selected as the new face of the note in 2019 following a public nomination process.
Centenary celebrations
To mark the 100th anniversary of Turing's birth, the Turing Centenary Advisory Committee (TCAC) co-ordinated the Alan Turing Year
The Alan Turing Year, 2012, marked the celebration of the life and scientific influence of Alan Turing during the centenary of his birth on 23 June 1912. Turing had an important influence on computing, computer science, artificial intelligence, ...
in 2012, a year-long programme of events around the world honouring Turing's life and achievements. The TCAC, chaired by S. Barry Cooper
S. Barry Cooper (9 October 1943 – 26 October 2015) was an English mathematician and computability theory, computability theorist. He was a professor of Pure Mathematics at the University of Leeds.
Early life and education
Cooper grew up in ...
with Turing's nephew Sir John Dermot Turing acting as Honorary President, worked with the University of Manchester faculty members and a broad spectrum of people from Cambridge University and Bletchley Park
Bletchley Park is an English country house and estate in Bletchley, Milton Keynes ( Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years followin ...
.
Notes and references
Notes
References
Sources
*
*
*
*
*
*
*
* Bruderer, Herbert
''Konrad Zuse und die Schweiz. Wer hat den Computer erfunden? Charles Babbage, Alan Turing und John von Neumann''
Oldenbourg Verlag, München 2012, XXVI, 224 Seiten,
*
*
*
*
*
*
*
*
*
** in
*
*
*
*
*
*
*
*
*
*
*
*
* Petzold, Charles (2008). "The Annotated Turing
''The Annotated Turing: A Guided Tour Through Alan Turing’s Historic Paper on Computability and the Turing Machine'' is a book by Charles Petzold, published in 2008 by John Wiley & Sons, Inc.
Petzold annotates Alan Turing's paper "On Computab ...
: A Guided Tour through Alan Turing's Historic Paper on Computability and the Turing Machine". Indianapolis
Indianapolis (), colloquially known as Indy, is the state capital and most populous city of the U.S. state of Indiana and the seat of Marion County. According to the U.S. Census Bureau, the consolidated population of Indianapolis and Marion ...
: Wiley Publishing.
* Smith, Roger (1997). ''Fontana History of the Human Sciences''. London: Fontana.
*
* Weizenbaum, Joseph (1976). ''Computer Power and Human Reason''. London: W.H. Freeman.
* and
* Turing's mother, who survived him by many years, wrote this 157-page biography of her son, glorifying his life. It was published in 1959, and so could not cover his war work. Scarcely 300 copies were sold (Sara Turing to Lyn Newman, 1967, Library of St John's College, Cambridge). The six-page foreword by Lyn Irvine
Lyn Lloyd Newman (née Irvine; 3 May 1901 – 19 May 1973) was a literary journalist and writer.
She was born in Berwick-upon-Tweed, the daughter of John A. Irvine, a Presbyterian minister, and his Irish wife Lilian; Andrew Irvine, who died ...
includes reminiscences and is more frequently quoted. It was re-published by Cambridge University Press in 2012, to honour the centenary of his birth, and included a new foreword by Martin Davis, as well as a never-before-published memoir by Turing's older brother John F. Turing.
* This 1986 Hugh Whitemore play tells the story of Turing's life and death. In the original West End and Broadway runs, Derek Jacobi
Sir Derek George Jacobi (; born 22 October 1938) is an English actor. He has appeared in various stage productions of William Shakespeare such as ''Hamlet'', ''Much Ado About Nothing'', '' Macbeth'', ''Twelfth Night'', '' The Tempest'', ''Kin ...
played Turing and he recreated the role in a 1997 television film based on the play made jointly by the BBC and WGBH, Boston. The play is published by Amber Lane Press, Oxford
Oxford () is a city in England. It is the county town and only city of Oxfordshire. In 2020, its population was estimated at 151,584. It is north-west of London, south-east of Birmingham and north-east of Bristol. The city is home to the ...
, ASIN: B000B7TM0Q
* Williams, Michael R. (1985) ''A History of Computing Technology'', Englewood Cliffs
Englewood Cliffs is a borough in Bergen County, in the U.S. state of New Jersey, whose population at the 2010 United States census was 5,281.[New Jersey
New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...]
: Prentice-Hall,
*
Further reading
Articles
*
*
*
*
*
*
Books
*
*
*
*
* (originally published in 1983); basis of the film ''The Imitation Game
''The Imitation Game'' is a 2014 American historical drama film directed by Morten Tyldum and written by Graham Moore, based on the 1983 biography '' Alan Turing: The Enigma'' by Andrew Hodges. The film's title quotes the name of the game c ...
''
* (originally published in 1959 by W. Heffer & Sons, Ltd)
External links
Oral history interview with Nicholas C. Metropolis
Charles Babbage Institute
The IT History Society (ITHS) is an organization that supports the history and scholarship of information technology by encouraging, fostering, and facilitating archival and historical research. Formerly known as the Charles Babbage Foundation, ...
, University of Minnesota. Metropolis was the first director of computing services at Los Alamos National Laboratory
Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development laboratories of the United States Department of Energy (DOE), located a short distance northwest of Santa Fe, New Mexico, ...
; topics include the relationship between Turing and John von Neumann
John von Neumann (; hu, Neumann János Lajos, ; December 28, 1903 – February 8, 1957) was a Hungarian-American mathematician, physicist, computer scientist, engineer and polymath. He was regarded as having perhaps the widest cove ...
How Alan Turing Cracked The Enigma Code
Imperial War Museums
Alan Turing Year
CiE 2012: Turing Centenary Conference
Science in the Making
Alan Turing's papers in the Royal Society's archives
Alan Turing
site maintained by Andrew Hodges
Andrew Philip Hodges (; born 1949) is a British mathematician, author and emeritus senior research fellow at Wadham College, Oxford.
Education
Hodges was born in London in 1949 and educated at Birkbeck, University of London where he was award ...
including
short biography
AlanTuring.net – Turing Archive for the History of Computing
by Jack Copeland
Brian John Copeland (born 1950) is Professor of Philosophy at the University of Canterbury, Christchurch, New Zealand, and author of books on the computing pioneer Alan Turing.
Education
Copeland was educated at the University of Oxford, obta ...
The Turing Archive
nbsp;– contains scans of some unpublished documents and material from the King's College, Cambridge archive
Alan Turing Papers
– University of Manchester Library
The University of Manchester Library is the library system and information service of the University of Manchester. The main library is on the Oxford Road campus of the university, with its entrance on Burlington Street. There are also ten other ...
, Manchester
*
Sherborne School Archives
– holds papers relating to Turing's time at Sherborne School
Alan Turing plaques
recorded on openplaques.org
Alan Turing
archive on New Scientist
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