True on Babbage - he was about 100 years before his
time, and his work was pretty much forgotten until the
later advent of electronics. But Turing? Sure, he
was persecuted, and killed himself at a young age, but
in the time he had he did invent most of the
theoretical basis of computation. A book I was
reading the other day had a great quote about him (in
reference to the concept of Turing machines and
computability): "In this, as in most areas, Turing had
both the first and last word."
>
You can read Andrew Hodges's sympathetic biography of Turing.
It isn't clear exactly why Turing killed himself, but homosexuality in conflict with American pressure on the British to purge Turing seems to me to be the likeliest cause.
I believe Turing continued doing work for GCHQ on cryptanalysis while working on the Manchester computer (if I don't have which computer garbled). He had already been convicted of homosexuality, and had submitted to court order, including hormone treatment that he complained made him grow breasts, and not having any homosexual contact in England.
So, he took to going to Norway for sexual adventures. I think this freaked the Americans out. Our spooks must have feared that Turing either had or would fall into the hands of the Russians. In addition, this was the time that our Senate declared in a report that homosexuals were security risks, touching off a nationwide witch-hunt.
I believe that our newly formed NSA put such pressure on British Intelligence that Turing knew he was doomed. They couldn't just dismiss him because he really knew the secrets of British and American codebreaking. He invented them (besides William Friedman, I mean).
I believe the British would have had to imprison him to ensure security. Therefore, he killed himself.
IMO, that's close to what happened.
Hodges has a web site devoted to Turing. It's at http://www.turing.org.uk/turing/
-- John K. Taber