TITLE: A Reflection on Alan Turing, the Turing Test, and Machine Intelligence AUTHOR: Eugene Wallingford DATE: March 30, 2012 5:22 PM DESC: ----- BODY:
Alan Turing
In 1950, Alan Turing published a paper that launched the discipline of artificial intelligence, Computing Machinery and Intelligence. If you have not read this paper, go and do so. Now. 2012 is the centennial of Turing's birth, and you owe yourself a read of this seminal paper as part of the celebration. It is a wonderful work from a wonderful mind. This paper gave us the Imitation Game, an attempt to replace the question of whether a computer could be intelligent by withn something more concrete: a probing dialogue. The Imitation became the Turing Test, now a staple of modern culture and the inspiration for contests and analogies and speculation. After reading the paper, you will understand something that many people do not: Turing is not describing a way for us to tell the difference between human intelligence and machine intelligence. He is telling us that the distinction is not as important as we seem to think. Indeed, I think he is telling us that there is no distinction at all. I mentioned in an entry a few years ago that I always have my undergrad AI students read Turing's paper and discuss the implications of what we now call the Turing Test. Students would often get hung up on religious objections or, as noted in that entry, a deep and a-rational belief in "gut instinct". A few ended up putting their heads in the sand, as Turing knew they might, because they simply didn't want to confront the implication of intelligences other than our own. And yet they were in an AI course, learning techniques that enable us to write "intelligent" programs. Even students with the most diehard objections wanted to write programs that could learn from experience. Douglas Hofstadter, who visited campus this month, has encountered another response to the Turing Test that surprised him. On his second day here, in honor of the Turing centenary, Hofstadter offered a seminar on some ideas related to the Turing Test. He quoted two snippets of hypothetical man-machoine dialogue from Turing's seminal paper in his classic Gödel, Escher, Bach. Over the the years, he occasionally runs into philosophers who think the Turing Test is shallow, trivial to pass with trickery and "mere syntax". Some are concerned that it explores "only behavior". Is behavior all there is? they ask. As a computer programmer, the idea that the Turing test explores only behavior never bothered me. Certainly, a computer program is a static construct and, however complex it is, we can read and understand it. (Students who take my programming languages course learn that even another program can read and process programs in a helpful way.) This was not a problem for Hofstadter either, growing up as he did in a physicist's household. Indeed, he found Turing's formulation of the Imitation Game to be deep and brilliant. Many of us who are drawn to AI feel the same. "If I could write a program capable of playing the Imitation Game," we think, "I will have done something remarkable." One of Hofstadter's primary goals in writing GEB was to make a compelling case form Turing's vision.
Douglas Hofstadter
Those of us who attended the Turing seminar read a section from Chapter 13 of Le Ton beau de Marot, a more recent book by Hofstadter in which he explores many of the same ideas about words, concepts, meaning, and machine intelligence as GEB, in the context of translating text from one language to another. Hofstadter said the focus in this book is on the subtlety of words and the ideas they embody, and what that means for translation. Of course, these are the some of the issues that underlie Turing's use of dialogue as sufficient for us to understand what it means to be intelligent. In the seminar, he shared with us some of his efforts to translate a modern French poem into faithful English. His source poem had itself been translated from older French into modern French by a French poet friend of his. I enjoyed hearing him talk about "the forces" that pushed him toward and away from particular words and phrases. Le Ton beau de Marot uses creative dialogues of the sort seen in GEB, this time between the Ace Mechanical Translator (his fictional computer program) and a Dull Rigid Human. Notice the initials of his raconteurs! They are an homage to Turing. The human translator, Douglas R. Hofstadter himself, is cast in the role of AMT, which shares its initials with Alan M. Turing, the man who started this conversation over sixty years ago. Like Hofstadter, I have often encountered people who object to the Turing test. Many of my AI colleagues are comfortable with a behavioral test for intelligence but dislike that Turing considers only linguistic behavior. I am comfortable with linguistic behavior because it captures what is for me the most important feature of intelligence: the ability to express and discuss ideas. Others object that it sets too low a bar for AI, because it is agnostic on method. What if a program "passes the test", and when we look inside the box we don't understand what we see? Or worse, we do understand what we see and are unimpressed? I think that this is beside the point. Not to say that we shouldn't want to understand. If we found such I program, I think that we would make it an overriding goal to figure out how it works. But how an entity manages to be "intelligent" is a different question from whether it is intelligent. That is precisely Turing's point! I agree with Brian Christian, who won the prize for being "The Most Human Human" in a competition based on Turing's now-famous test. In an interview with The Paris Review, he said,
Some see the history of AI as a dehumanizing narrative; I see it as much the reverse.
Turing does not diminish what it is to be human when he suggests that a computer might be able to carry on a rich conversation about something meaningful. Neither do AI researchers or teenagers like me, who dreamed of figuring just what it is that makes it possible for humans to do what we do. We ask the question precisely because we are amazed. Christian again:
We build these things in our own image, leveraging all the understanding of ourselves we have, and then we get to see where they fall short. That gap always has something new to teach us about who we are.
As in science itself, every time we push back the curtain, we find another layer of amazement -- and more questions. I agree with Hofstadter. If a computer could do what it does in Turing's dialogues, then no one could rightly say that it wasn't "intelligent", whatever that might mean. Turing was right. ~~~~ PHOTOGRAPH 1: the Alan Turing centenary celebration. Source: 2012 The Alan Turing Year. PHOTOGRAPH 2: Douglas Hofstadter in Bologna, Italy, 2002. Source: Wikimedia Commons. -----