SCOTT SIMON, HOST:
Alan Turing was born a hundred years ago today. He was a British mathematician and computer pioneer, and may have done as much as any soldier or statesman to win World War II. And his work continues to reveal itself in our everyday lives. WEEKEND EDITION's math guy Keith Devlin joins us from the studios of Stanford University, where he's also a professor.
Keith, thanks for being with us.
KEITH DEVLIN, BYLINE: Nice to be with you again, Scott.
SIMON: In addition to his role in World War II, he's best known among mathematicians for solving something called the David Hilbert's Decision Problem.
DEVLIN: That's right. And that was a problem that had been around since the 1920s. It was an abstract problem in mathematics. And he thought up this idea of a theoretical computing device that could be programmed to solve problems. Not only did he think about it, he proved that you could actually build one of these things. We now call these things Turing machines.
SIMON: So when we call him a computer pioneer this is not just the first man to walk over the landscape. This is a man who put the landscape in place.
DEVLIN: Oh, in fact, when computers were actually built, they were very similar in many ways to that theoretical Turing machine that he'd invented. He went to Princeton to do a Ph.D. And at Princeton at the time people were beginning to build the precursors of computers. And Turing was involved in that and that was a lucky break.
Then when he goes back to the U.K. in the Second World War, he gets involved at the famous Bletchley Park code-breaking house and builds computers to help solve the German Enigma code.
SIMON: Alan Turing received the Order of the British Empire for his contribution. And yet by 1952, this hero was charged with a criminal act for having a consensual homosexual relationship, which was then illegal. His security clearance was yanked, and the story gets really sad after this.
DEVLIN: Yeah, it does. And it's bizarre, because the authorities only discovered it because Turing - there was a break-in at house. He reported it. And he said he thinks it was this particularly person he'd dealt with and simply tells the police very naively, oh yes, I was having a homosexual relationship with this person. So then the authorities come down and, as you say, his security clearance was revoked.
But he was offered treatment with female hormones as an alternative to going to prison. And he took that and either because of the effect of the hormones or just the whole stress of the thing, a couple of years later in 1954, he kills himself. He laces an apple with cyanide, bites into it and dies instantly. And then he's found the next day dead of cyanide poisoning.
SIMON: Where do you see Alan Turning in our lives today?
DEVLIN: Oh, wow. I see it every time I pull the iPhone out of my pocket, because that's an instantiation of what in 1936 he proved was possible. You know, I think it about 1999 or 2000 that Time magazine named Turing one of the 100 most important people of the 20th century because of his role in creating the computer. I would probably put him in the top 50 because of the impact that computers have had on our lives on a large scale and on a very local and personal sale.
SIMON: WEEKEND EDITION's math guy Keith Devlin, speaking with us from Stanford. Thanks so much, Keith.
DEVLIN: My pleasure, Scott. Bye bye.
SIMON: This is NPR News. Transcript provided by NPR, Copyright NPR.