Alan Turing was a British scientist and a pioneer in computer science. During World
War II, he developed a machine that helped break the German Enigma code. He also
laid the groundwork for modern computing and theorized about artificial intelligence.
An openly gay man during a time when homosexual acts were illegal in Britain, Turing
committed suicide after begin convicted of "gross indecency" and sentenced to a
procedure some call "chemical castration." He has since become a martyred hero of
the gay community. In late 2013, nearly 60 years after his death, Queen Elizabeth II
formally pardoned him.
Early life
Born on June 23, 1912, Turing was part of an upper-middle-class British family
involved in colonial India. Science was a passion for young Turing, who often took
part in primitive chemistry experiments. Before applying to schools, Turing was
already theorizing on relativity and quantum mechanics.
While attending King's College, Cambridge, Turing focused on his studies, and his
passion for probability theory and mathematical logic propelled his career. At the
same time, he was also becoming more aware of his identity as a gay man, and his
philosophy was becoming closely aligned with the liberal left.
Turing machine
In the years after college, Turing began to consider whether a method or process
could be devised that could decide whether a given mathematical assertion was
provable. Turing analyzed the methodical process, focusing on logical instructions,
the action of the mind, and a machine that could be embodied as a physical form.
Turing developed the proof that automatic computation cannot solve all mathematical
problems. This concept became known as the Turing machine, which has become the
foundation of the modern theory of computation and computability.
The Bletchley Park clock tower, British code-breaking headquarters during World War
II, where Alan Turing broke the Enigma code.
The Bletchley Park clock tower, British code-breaking headquarters during World War
II, where Alan Turing broke the Enigma code. (Image credit: Terence Mendoza
Shutterstock)
Turing took this idea and imagined the possibility of multiple Turing machines, each
corresponding to a different method or algorithm. Each algorithm would be written
out as a set of instructions in a standard form, and the actual interpretation work
would be considered a mechanical process. Thus, each particular Turing machine
embodied the algorithm, and a universal Turing machine could do all possible tasks.
Essentially, through this theorizing, Turing created the computer: a single machine
that can be turned to any well-defined task by being supplied with an algorithm, or
a program.
Turing moved to the United States to continue his graduate studies at Princeton. He
worked on algebra and number theory, as well as a cipher machine based on
electromagnetic relays to multiply binary numbers. He took this research back to
England with him, where he secretly worked part time for the British cryptanalytic
department. After the British declared war in 1939, Turing took up full-time
cryptanalytic work at Bletchley Park.
Enigma code
Turing made it his goal to crack the complex Enigma code used in German naval
communications, which were generally regarded as unbreakable. Turing cracked the
system and regular decryption of German messages began in mid-1941. To maintain
progress on code-breaking, Turing introduced the use of electronic technology to
gain higher speeds of mechanical working. Turing became an invaluable asset to the
Allies, successfully decoding many German messages. [Video: Decoding the Mysterious
World of Code-Breakers]
By the end of the war, Turing was the only scientist working on the idea of a
universal machine that could plug into the potential speed and reliability of
electronic technology. This led to the development of early hardware and the
implementation of arithmetical functions by programming, and thus, computer science
was born. Turing became well-regarded by the scientific community, as the director
of the computing laboratory at Manchester University and an elected fellow of the
Royal Society.
Turing test
Turing was also involved in philosophical debates over whether machines could think
like a human brain. He devised a test to answer the question. He reasoned that if a
computer acted, reacted and interacted like a sentient being, then it was sentient.
[Related: What is The Singularity?]
In this simple test, an interrogator in isolation asks questions of another person
and a computer. The questioner then must distinguish between the human and the
computer based on their replies to his questions. If the computer can "fool" the
interrogator, it is intelligent. Today, the Turing Test is at the heart of
discussions about artificial intelligence.
Gross indecency
Turing had never been secretive about his homosexuality. He was outspoken and
exuberant about his lifestyle, openly taking male lovers. When police discovered his
sexual relationship with a young man, he was arrested and came to trial in 1952.
Turing never denied or defended his actions, instead asserting that there was
nothing wrong with what he did. The courts disagreed, and Turing was convicted of
gross indecency. In order to avoid prison, Turing had to agree to undergo a series
of estrogen injections. [Countdown: 10 Milestones in Gay Rights History]
He continued his work in quantum physics and in cryptanalytics, but known
homosexuals were ineligible for security clearance. Bitter over being turned away
from the field he had revolutionized, Turing committed suicide in 1954 by ingesting
cyanide.
In 2009, Prime Minister Gordon Brown publicly apologized for how the scientist was
treated. And in December 2013, Queen Elizabeth II formally pardoned Turing. A
British government statement said, "Turing was an exceptional man with a brilliant
mind" who "deserves to be remembered and recognized for his fantastic contribution
to the war effort and his legacy to science."
Alan Turing quotes
"We can only see a short distance ahead, but we can see plenty there that needs to
be done."
"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."
"Mathematical reasoning may be regarded rather schematically as the exercise of a
combination of two facilities, which we may call intuition and ingenuity."