# Alan Turing

## Contents

## Alan Turing's Social Links

## Profile

Alan Turing, widely considered to be the father of both theoretical computer science and artificial intelligence, is the brilliant mind behind a wide array of contributions to technology and mathematics. Conceived in India, where his father Julius was a member of the Indian Civil Service, Turing was born on June 23, 1912 in Paddington, London. Along with his elder brother John, he was fostered in the seaside home of a retired Army couple until his father’s retirement from India in 1926. He showed an early interest in scientific inquiry, a tendency his mother feared would prevent his entry into public school. In 1926, however, he entered the Sherborne School, where he would study until 1931.

While at Sherborne, Turing met Christopher Morcom, a fellow student who shared Turing’s passion for science and mathematics. When Morcom died suddenly of bovine tuberculosis in 1930, Turing honored his companion by pouring himself into continuing to explore their shared love of science. After graduating from Sherborne in 1931, he proceeded to Cambridge University’s King’s College to pursue undergraduate work, earning first-class honours in mathematics.

By 1935, at the young age of twenty-two, Turing was elected a Fellow of King’s College. Free to pursue whatever lines of inquiries he found intriguing, Turing began exploring an unresolved mathematical principle known as the Entscheidungsproblem, or “decision problem.” In his paper on the subject, “On Computable Numbers, with an Application to the Entscheidungsproblem,” Turing introduced a simple hypothetical device that would lay the groundwork for modern computer science. He proved that the devices, now known as Turing machines, would be capable of performing any mathematical computation, given that it was representable as an algorithm. He also introduced the concept of the ‘Universal Machine,’ now known as the Universal Turing Machine, which he proved to be capable of performing the task of any other computation machine. It’s generally acknowledged that the evolution of modern computing is largely due to this paper.

Though Turing was unaware of it at the time, Alonzo Church had been constructing an equivalent proof, published slightly before Turing’s. Turing would study under Church at Princeton from 1936 until 1938, doing work in both pure mathematics and in cryptology. After obtaining his PhD from Princeton, he returned to Cambridge, attending lectures on the foundations of mathematics by Ludwig Wittgenstein and beginning part-time work with the Government Code and Cypher School.

On September 4, 1939, Britain officially declared war on Germany. Turing reported for full-time work at Bletchley Park, the war effort’s cryptanalytic headquarters. Evolving concepts laid out by Polish mathematicians, Turing created the bombe, a device capable of deciphering any German Enigma message given that a small piece of plain text could be correctly identified. Throughout the war, Turing would lead a series of important code-breaking efforts, including deducing the indicator procedure used by the German navy; developing Banburismus, a statistical procedure for the more efficient use of bombes; and developing Turingery, a procedure for working out the cam settings of the wheels of the Lorenz SZ 40/42. Near the end of the war, he also developed Delilah, a portable secure voice scrambler.

Unkempt and quirky, Turing was known amongst his Bletchley Park colleagues for his eccentricities. An avid long-distance runner, he would occasionally run the forty miles to London for high-level meetings. In 1948, he tried out for the British Olympic team. Running with an injury, his tryout time was still only eleven minutes slower than the run that would win Thomas Richards the silver medal. It was during his time at Bletchley Park that Turing came as close as he ever would to marriage, proposing to colleague Joan Clarke. Though she accepted, he eventually broke the engagement after revealing to Clarke his homosexuality.

After the war, Turing turned his attention to exploring early computing. Between 1945 and 1947, he worked at the National Physical Laboratory, designing the Automatic Computing Engine (ACE). In 1946, he presented a paper featuring the first detailed design of a stored-program computer. When the secrecy surrounding the wartime work at Bletchley Park led to delays in implementing ACE’s design, Turing became frustrated and disillusioned with the project. He returned to Cambridge, taking a sabbatical year to write Intelligent Machinery, an important work that he would not see published in his lifetime. The ACE was never built, though many future computers would owe much to its design.

In 1948, Turing was appointed Reader in the University of Manchester’s Mathematics Department. A year later, he was appointed Deputy Director of the university’s Computing Laboratory, working on the Manchester Mark 1, one of the earliest stored-program computers. It was during his time in Manchester that Turing began exploring the problem of artificial intelligence, developing his famous Turing test. The test proposes that a machine could be thought to “think,” and therefore be called “intelligent,” if a human interrogator could not tell it apart from a human being in conversation. Turing proposed the idea that, rather than trying to emulate the adult mind, it would be better to create a program similar to a child’s mind and put it through a course of education. Both this concept and the Turing test itself have been central to the development of and debate around artificial intelligence to this day.

Turing shifted his focus to mathematical biology, specifically morphogenesis, in 1952. In January of that year, he also began a relationship with 19-year-old Arnold Murray. Later that month, Turing’s house was burgled. Murray claimed to know the burglar, and so Turing reported the crime to the police, acknowledging his sexual relationship with Murray during the investigation. As homosexual acts were criminal offences in the United Kingdom at the time, both Turing and Murray were charged with gross indecency. Turing pled guilty, and was offered a choice between imprisonment and probation. The latter option, however, was contingent on his agreement to undergo a hormonal treatment to decrease libido, essentially a form of chemical castration. Turing assented to this option, which rendered him impotent and caused gynaecomastia.

After his conviction, Turing was considered untrustworthy by the British government. His security clearance was removed, barring him from continuing his cryptographic work. He took to travel, visiting more accepting European countries, including Norway and Greece.

On June 8, 1954, Turing was found dead by his housekeeper. Post-mortem examination placed cyanide poisoning as cause of death. An inquest determined Turing had committed suicide, self-administering the fatal chemical in a half-eaten apple found by his bed. Alternate theories surrounding his death abound, however, including a laboratory accident or assassination.

After his death, Turing received wide-recognition for his contributions to mathematics, computer science, and the war effort. He had been awarded the OBE in 1945, for his wartime cryptology work, but the nature of his work remained secret for many years after his death. Since 1966, the Association for Computing Machinery has awarded the Turing Award. The award, which recognizes contributions to the computing community, is widely considered to be the computing world’s Nobel Prize. Widely considered the father of modern computing, he’s been widely recognized in commemorative acts, biographical work, and popular culture. On December 24, 2013, Turing was formally pardoned by the British government, acknowledging that his incredible mind should be “remembered and recognized for his fantastic contribution to the war effort,” and not for his criminal conviction.

## Companies and Investments

Government Code and Cypher School (Cryptanalyst), University of Manchester Computing Laboratory (Deputy Director), University of Manchester Mathematics Department (Reader), King’s College, Cambridge (Fellow)

## Lessons Learned

The view that machines cannot give rise to surprises is due, I believe, to a fallacy to which philosophers and mathematicians are particularly subject. This is the assumption that as soon as a fact is presented to a mind all consequences of that fact spring into the mind simultaneously with it. It is a very useful assumption under many circumstances, but one too easily forgets that it is false. A natural consequence of doing so is that one then assumes that there is no virtue in the mere working out of consequences from data and general principles. (Turing on working things out rather than relying on assumptions, in his paper Computing Machinery and Intelligence.)

I am not very impressed with theological arguments whatever they may be used to support. Such arguments have often been found unsatisfactory in the past. In the time of Galileo it was argued that the texts, "And the sun stood still... and hasted not to go down about a whole day" (Joshua x. 13) and "He laid the foundations of the earth, that it should not move at any time" (Psalm cv. 5) were an adequate refutation of the Copernican theory. (Turing on seeing beyond dictums to allow for revolutionary ideas, in his paper Computing Machinery and Intelligence)

I believe that at the end of the century the use of words and general educated opinion will have altered so much that one will be able to speak of machines thinking without expecting to be contradicted. (Turing on the potential of computers and technology, and the evolutionary capabilities of society, in his paper Computing Machinery and Intelligence)

## Inspiring Quotes

## Alan Turing's Quotes

“ | Codes are a puzzle. A game, just like any other game. | ” |

“ | If a machine is expected to be infallible, it cannot also be intelligent. | ” |

“ | Sometimes it is the people no one can imagine anything of who do the things no one can imagine. | ” |

“ | A man provided with paper, pencil, and rubber, and subject to strict discipline, is in effect a universal machine. | ” |

“ | We can only see a short distance ahead, but we can see plenty there that needs to be done. | ” |

## Influential Books

Alfred North Whitehead - Principia Mathematica - Volume One

Edwin Tenney Brewster - Natural Wonders Every Child Should Know

## Mentors

## References

## Technical

- Codes are a puzzle. A game, just like any other game.
- If a machine is expected to be infallible, it cannot also be intelligent.
- Sometimes it is the people no one can imagine anything of who do the things no one can imagine.
- A man provided with paper, pencil, and rubber, and subject to strict discipline, is in effect a u...
- We can only see a short distance ahead, but we can see plenty there that needs to be done.
- Alfred North Whitehead - Principia Mathematica - Volume One
- Edwin Tenney Brewster - Natural Wonders Every Child Should Know
- Entrepreneur