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Alan Turing the enigma
The story of a brilliant scientist destroyed by the Post World War II homophobia
It would not be exaggerating to say that Alan Mathison Turing, born on June 23, 1912, was Britain’s secret weapon against the German’s during World War II. This biography by Andrew Hodges details the life of this complex and conflicted man from the heights as one of Britain brightest minds to the depths on June 8,1954 when he took his own life by cyanide poisoning.
In his short 42 years on earth, he contributed heavily to the knowledge of mathematics and science. In 1935 he created the Turing machine, the basis for modern day digital computers. In 1940 he created the computing machine that broke the German Enigma cipher. In 1945 he help in the creation of the ACE (Automatic Computing Engine) computer. And finally, in 1950 he contributed the morphogenetic principle.
Author Hodges describes Turing using the typewriter as the model for a more general-purpose computing machine. "But a typewriter was too limited to serve as a model. It dealt with symbols, but it could only write them, and it required a human operator to choose the symbols and changes of configuration and position, one at a time… To be a ‘machine’ it would have to retain the typewriter’s quality of having a finite number of configurations, and an exactly determined behaviour in each. But it would have to be capable of much more."
Enigma was to prove a way of applying his theoretical machine to a real problem of breaking the cipher. "In practical cryptography, as opposed to the setting of isolated puzzles, there would usually be some part of the message transmitted which did not convey the text itself, but which conveyed instructions on how to decipher it." Hodges writes.
"It must surely have struck Alan, who had been thinking at least since 1936 about ‘the most general kind of code or cipher,’ that this mixing of instructions and data within a transmission was reminiscent of his ‘universal machine,’ which would first decipher the ‘description number’ into an instruction, and then apply that instruction to the contents of its tape. Indeed, any cipher system might be regarded as a complicated ‘mechanical process’ or Turing machine, involving not just the rules for adding or substituting, but rules for how to find, apply and communicate the method of encipherment itself."
Later, in 1947, Turing wrote a paper that was to become the blueprint for a more general-purpose computer. To be known as ACE, it would come much closer to representing his initial vision of the universal machine he had described in 1935, which everyone else would come to refer to as the Turing machine. The ACE would be a computer much more like today’s modern computers than many others of the day.
"…his report placed no great emphasis upon the fact that the ACE would use binary arithmetic. He stated the advantage of the binary representation, namely that electronic switches could naturally represent ‘1s’ and ‘0s’ by ‘on’ and ‘off’." Furthermore, Turing was interested in the ability of ACE to perform logical operations. "In his philosophy it was almost an extravagance to supply addition and multiplication facilities as hardware, since in principle they could be replaced by instructions applying only the more primitive logical operations of OR, AND and NOT…
"To Alan Turing,…the heart lay in the logical control, which took instructions from the memory, and put them into operation," Hodges writes. "In reality, he did include special hardware to perform arithmetic tasks, but even these he decomposed the arithmetical operations into small pieces so that he could economise on hardware at the cost of more stored instructions."
Beyond computers, Turing developed an interest in how "biological matter could assemble itself into patterns which were so enormous compared with the size of the cells." Hodges writes. Turing’s response was The Chemical Basis of Morphogenesis, a paper written in 1952 which was the first work in the new discipline of modern non-linear dynamic theory. "The natural world was overflowing with examples of pattern; it was like codebreaking, with millions of message waiting to be decrypted. Like codebreaking, the field was open-ended; with his chemical model he had one sharp tool to apply to it, but that was only the beginning."
The great irony in this story is that the very country he served so well was to turn on this brilliant man and drive him to his untimely death. He was arrested by the police for engaging in a sexual relationship with a young Manchester man. Seeing nothing wrong in his actions he made no serious denial or defense of his action. He was sentenced to have injections of estrogen for a year to neutralize his libido. Ultimately, he chose not to live in a world that would not accept him as he was.
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