Friday, February 03, 2006

New Yorker Turing profile

A nice overview of Turing's life here in the guise of a review of the new biography by David Leavitt. Not surprisingly, Leavitt's book falls short of the wonderful Alan Turing: The Enigma by Andrew Hodges, himself a mathematical physicist.

Turing's unique contributions enjoy greater appreciation as time goes on. Turing solved a fundamental problem in mathematical logic as a byproduct of conceptualizing the notion of a universal computer, played the single largest role in breaking the German Enigma code (crucial to winning WWII), designed and built one of the first electronic computers, and pioneered the idea of artificial intelligence. It was a terrible tragedy for science that his life ended so early, at age 41.

...But the death of Leibniz’s dream turned out to be the birth of the computer age. The boldest idea to emerge from Turing’s analysis was that of a universal Turing machine: one that, when furnished with the number describing the mechanism of any particular Turing machine, would perfectly mimic its behavior. In effect, the “hardware” of a special-purpose computer could be translated into “software” and then entered like data into the universal machine, where it would be run as a program—the way, for example, the operating system on your laptop treats a word-processing program as data. What Turing had invented, as a by-product of his advance in logic, was the stored-program computer.


Emma Eckstein said...

Turing was a great guy, but the single greatest mathematical insight that made solving the Enigma code tractable was Marian Rejewski's realization that the cycle structure of the permutation depends on the initial setting of the rotor, not on the plugboard connections, which only changes the letters.


Dave Bacon said...

Turing's insight about universal computers is so taken for granted these days that I think we forget how important an insight it was.

Another thing Turing did was to rediscover the quantum zeno effect and he had a very strong interest in the foundations of quantum theory. I sometimes wonder if he had lived longer if the idea of quantum computers would have arisen earlier. Of course there were technological reasons not to think about quantum computation when he died: I mean Schrodinger didn't even believe we would ever experiment with single quantum systems!

steve said...

Emma: Good point. The Poles were working on Enigma for many years before the British. Perhaps I should have written that Turing's contribution was the greatest at Bletchley Park!

Dave: I think Turing's stock will continue to grow with time. He really was a tremendously deep thinker.

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