Turing’s Cathedral

I’ve been re-reading George Dyson’s wonderful essay on Google, “Turing’s Cathedral“. You should read it.

“It was Turing, in 1936, who showed von Neumann that digital computers are able to solve most — but not all — problems that can be stated in finite, unambiguous terms. They may, however, take a very long time to produce an answer (in which case you build faster computers) or it may take a very long time to ask the question (in which case you hire more programmers). Computers have been getting better and better at providing answers — but only to questions that programmers are able to ask.

We can divide the computational universe into three sectors: computable problems; non-computable problems (that can be given a finite, exact description but have no effective procedure to deliver a definite result); and, finally, questions whose answers are, in principle, computable, but that, in practice, we are unable to ask in unambiguous language that computers can understand.

We do most of our computing in the first sector, but we do most of our living (and thinking) in the third. In the real world, most of the time, finding an answer is easier than defining the question. It’s easier to draw something that looks like a cat, for instance, than to describe what, exactly, makes something look like a cat. A child scribbles indiscriminately, and eventually something appears that resembles a cat. A solution finds the problem, not the other way around. The world starts making sense, and the meaningless scribbles (and a huge number of neurons) are left behind.

This is why Google works so well. All the answers in the known universe are there, and some very ingenious algorithms are in place to map them to questions that people ask.


My visit to Google? Despite the whimsical furniture and other toys, I felt I was entering a 14th-century cathedral — not in the 14th century but in the 12th century, while it was being built. Everyone was busy carving one stone here and another stone there, with some invisible architect getting everything to fit. The mood was playful, yet there was a palpable reverence in the air. “We are not scanning all those books to be read by people,” explained one of my hosts after my talk. “We are scanning them to be read by an AI.”

When I returned to highway 101, I found myself recollecting the words of Alan Turing, in his seminal paper Computing Machinery and Intelligence, a founding document in the quest for true AI. “In attempting to construct such machines we should not be irreverently usurping His power of creating souls, any more than we are in the procreation of children,” Turing had advised. “Rather we are, in either case, instruments of His will providing mansions for the souls that He creates.”

Google is Turing’s cathedral, awaiting its soul. We hope. In the words of an unusually perceptive friend: “When I was there, just before the IPO, I thought the coziness to be almost overwhelming. Happy Golden Retrievers running in slow motion through water sprinklers on the lawn. People waving and smiling, toys everywhere. I immediately suspected that unimaginable evil was happening somewhere in the dark corners. If the devil would come to earth, what place would be better to hide?” ”

Full essay.

Few know how to ask good questions–of computers or of each other. And fewer still know how to listen, in a culture that babbles or sits slack-jawed. John Battelle has some free advice on the subject for the MacArthur Foundation.

“…we suffer – in the US, certainly, and I imagine abroad as well – from a significant lack of what I might call 21st century literacy. By this I do not mean technological literacy, though that is certainly part of it. Instead, what I find seems to be missing, and in fact, is in serious retreat at least in our public schools, is what we often call “critical thinking” – the ability to look at all the available facts and, based on reason and a sense of fairness, determine a best course of action.

Our schools are instead focused on a testing regime which requires that students focus not on solving problems or determining best courses of action, but rather regurgitating answers. But as many wiser than I have noted through the course of history, the most creative act a human can engage in is not repeating an answer, it is forming a good question.

In an age where the knowledge of mankind is increasingly at our fingertips through the services of Internet search, we must teach our children critical thinking. One can never have all the answers, but if prepared, one can always ask the right question, and from that creative act, learn to find his or her own answer.

Instead, we have leaders that believe that questions have one answer, and they already know what it is. Their mission, then, is to evangelize that answer. That, to me, is a dangerous course. Reversing it by teaching our children to learn, rather than to answer, seems to me to be a noble cause.

I then later added:

Developing a framework in our schools for “search literacy” – how to use and think about using a search engine – might be just the kind of thing you could do with a modest investment….”