Walby argued that the Turing Test was flawed because machine intelligence ought not to be judged solely by comparison to human intelligence. He made the point that artificial intelligence could and should develop in ways that are unique to machines.
I agreed whole-heartedly with his point about machine intelligence, but took the position that the Turing Test was never intended to be an exhaustive test for any and every type of machine intelligence, built on the assumption that it must necessarily resemble human intelligence.
Rather, the Turing Test allows us to search for evidence of a specific type of machine intelligence that, once found, would be easy to recognize and particularly hard to refute or disqualify: the kind that resembles human intelligence.
Since I posted that piece we’ve had the long-awaited Turing Centenary, the June 23 celebration of Turing’s 100th birthday. Now that the hoopla’s died down and everyone has recovered from the hangovers they doubtless incurred playing Turing drinking games into the wee hours of June 24th, I want to return to that thought from a slightly different angle.
Consider another search for non-human intelligence: SETI is the Search for Extra-Terrestrial Intelligence. Its object is to locate, if possible, life on other planets.
This search has traditionally been conducted by scanning the sky for radio transmissions that would indicate the presence of alien intelligence on other planets. Stephen Hawking discusses the famous “wow” signal detected in the 1970s in the video below.
The search for a radio signal relies relatively little on preconceptions about the form of life we might find, having been constructed around the possibilities for telecommunication that are inherent in electromagnetic radiation and that are therefore available to a broad range of possible life forms.
But recently the search for life on other planets has found an additional focus: the planets themselves. This development has been made possible by technological innovations that make the detection of distant planets possible for the first time, and that increasingly allow us to make deductions about the environment on extra-solar planets.
In this context, we have begun looking for Earth-like planets, the ideal candidate having a rocky core that is the right distance from its local star to allow for liquid water and sufficient mass to permit it to hold an atmosphere. This type of search is constructed specifically to search for life that resembles us, because it looks for environments like the one in which we evolved.
The National Geographic video below gives some details about one candidate planet, Gliese 581.
But the search for life that resembles us through the detection of planets similar to ours doesn’t mean that we believe life must resemble us. It’s simply a technique for locating environments that could produce a type of life that we can readily recognize (because it’s like us) and that would leave little room for controversy over whether it constitutes life or not (again, due to its resemblance to Earth life forms).
There is no contradiction in carrying out a search of this kind while acknowledging that environments very different from Earth could allow for the evolution of life forms very different from those we’re familiar with, like those discussed in the video below.
The Turing Test is like the search for Earth-like planets. Out of the myriad of possible forms of intelligence, it is intentionally constrained to forms that are similar to human intelligence, not because that’s the only kind of intelligence that Turing believed could exist — he explicitly said otherwise — but because it’s the type that is easiest to recognize and most difficult to refute.
This isn’t a weakness of the Turing Test, it’s one of its great strengths.
The main thrust of Walby’s argument seems to be that Turing was misguided in recommending that we measure the ability of a machine to think by using human intelligence as a standard:
But Turing was wrong. A machine should not demonstrate intelligence by emulating a human. In fact, in some regards today’s expert systems are displaying intelligence far beyond the capability of a human. Should we mask such intellectual prowess in order for the machine to appear human, or allow it to run free to reach its full potential?
So is the Turing Test flawed and — as Walby later suggests — in need of replacing with a more satisfactory process?
How the Turing Test Works
First, for those who are new to this area — many people are learning about Turing and his work for the first time this year — a quick review of how the Turing Test works.
The test, or the Imitation Game as Turing himself called it, requires three participants:
a human judge
a hidden human who communicates with the judge only in writing, basically by text message
a hidden artificial intelligence that similarly communicates with the judge only in writing
The judge knows that either participant 2 or participant 3 is a computer while the other is human, and 2 and 3 both have to try to convince the judge that they’re the human being. If the computer succeeds — if it can act human enough to fool a human judge — it has passed the Turing Test and has earned the right to be treated as intelligent without any consideration of the means by which it managed that persuasion.
Turing introduces the idea of the Imitation Game to the reader gradually by first having the hidden participants be a man and a woman, with the judge having to figure out which is which. This is a parlour game version of the Imitation Game.
He then replaces the woman with a machine to turn the parlour game into a scientific enquiry and get at the question of machine intelligence. Remember that the paper was published in 1950 when Turing was in the process of inventing the discipline of artificial intelligence, so at the time this process would have eased readers into unfamiliar territory.
A copy of the issue of Mind in which Turing´s paper appeared (click to go to PDF)
Is the Flaw in the Turing Test Real?
So is Walby right? This would be a boring post if I simply agreed with him, and overall I won’t (though his post is interesting and my critique is intended to be friendly and respectful). But I want to start by agreeing on this point: machine intelligence should not be judged solely in comparison to human intelligence.
(One of my other blogs, Homo Artificialis, looks at disciplines that could eventually contribute to the creation of synthetic human bodies, artificial intelligence, or both, including AI, robotics, nanomedicine, brain-computer interfaces, artificial organs, tissue engineering, and xenotransplantation. If you’ve visited Homo Artificialis you’ll know that I’m at least notionally sympathetic to the idea of free range artificial intelligence developing on its own terms into its own most realized form.)
Homo Artificialis Site
The trouble with Walby’s argument is that I don’t think Turing ever said that artificial intelligence should be judged by human standards — he simply never made the claim that Walby is disputing.
In his seminal paper “Computing Machinery and Intelligence” [pdf] — the paper in which he codifies his famous test — Turing directly addressed the possibility that machines might ultimately be possessed of some form of intelligence unique to them and distinguishable from that of human beings:
May not machines carry out something which ought to be described as thinking but which is very different from what a man does?
He then simply puts this issue to one side, not because he’s dismissing it — he explicitly doesn’t dismiss it — but because it’s not the topic he’s addressing:
This objection is a very strong one, but at least we can say that if, nevertheless, a machine can be constructed to play the imitation game satisfactorily, we need not be troubled by this objection.
In other words, Turing agrees that machine intelligence may comprise different types, including some that do resemble human intelligence and some that don’t. The fact that there may be types that don’t simply doesn’t affect the subject of his enquiry: the types that do.
Indeed, while Turing famously starts the paper by asking “can machines think?”, later he is at pains to carefully circumscribe the question he’s addressing and to distinguish it from that larger, initial question:
We now ask the question, “What will happen when a machine takes the part of A [participant 3, above] in this game?”
Will the interrogator decide wrongly as often when the game is played like this as he does when the game is played between a man and a woman?
These questions replace our original, “Can machines think?”[emphasis added]
What the Turing Test Does
The Turing Test is not an exhaustive test for any and all kinds of artificial intelligence and I think it’s apparent that it wasn’t constructed to be.
What it is, is a test for a particular kind of evidence of artificial intelligence and it was carefully created to find the kind of evidence that is most persuasive to even the most skeptical of doubters.
We human beings ascribe intelligence to each other all the time even though we have no direct experience of another person’s intellect in action (a fact that Turing explicitly acknowledges in his discussion of the Argument from Consciousness).
We witness other people’s actions and hear or read their words, but that’s not conclusive of their engaging in thought. Maybe they’re actually hallucinations without intellects of their own, conjured up by our own minds. Or perhaps they’re illusions without substance projected by manipulative alien creatures in a Star Trek episode.
We have no direct evidence that other people think, but there is nonetheless a logic to our assumption that they do. If you compare the actions and words of other people with your own, and find a high degree of similarity, it’s logical to conclude that since you have intelligence and they behave like you do, then they must have intelligence as well.
(We don’t actually think this process through, its an assumption we make, but making the assumption that other things that behave like you are like you is useful from the point of view of survival. Other animals do this as well, like a cat treating a wiggling piece of string as though it were living prey or hissing defensively at a self-propelled toy.)
This is a process in which we all engage and the strength of the Turing Test is that it takes this pre-existing reaction that we universally share and applies it to the question of machine intelligence. It says: if and when a machine can do the things that we ourselves do, then at that point we will make the same assumption about the machine that we do about other people, that is, that it is thinking.
Seeing our own reflection in others
The Turing Test Doesn’t Need Turing to Function
When the Turing Test is viewed in this light, it can be seen not as Turing’s invention, but as his recognition of a naturally-occuring process that would eventually be applied to artificial constructs (once they were sophisticated enough to engage it) just as it’s always been applied to natural creatures.
Arguing with it makes little sense because it’s simply what we have always done and will continue to do: react to other things based upon their resemblance to us.
And by now our artificial constructs have finally become sophisticated enough to engage this instinct. When we recognize the spooky near-humanity of some piece of CGI that doesn’t quite fool us into thinking it’s a person, we’re giving it a failing grade in a kind of Turing Test that we automatically apply to the everything around us.
The tension and unease that arise when something almost passes the test, but doesn’t quite, was described in 1970 by Japanese robotics professor Masahiro Mori as the “uncanny valley,” [Wikipedia, Mori's paper] and it’s well illustrated by the video below.
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Walby’s Argument for a New Turing Test
Terry Walby concludes that a new Turing Test is needed. Given the arguments above, should we reject this conclusion? I don’t think so.
If, as I’ve argued, Walby mistakes the Turing Test for something it isn’t, that doesn’t change the fact that the thing he’s calling for would be a damned useful thing to have.
Turing purposely sidestepped an exhaustive definition of “thinking” in order to get to a practical test for a particular kind of thinking — the kind humans do.
But thinking is not a unitary thing. At a minimum, each of us experiences different kinds of thinking at different moments in our lives. ”Thought” is not a point on a graph, it’s a blob that stretches along the X and Y axes (and possibly the Z as well), encompassing a variety of intellectual functions.
Any tool that helps us to explore, describe, and understand the territory that “thinking” maps on that graph is beneficial and worth working toward.
Every once in a while I’m not looking for Turing, but I find him anyway. Is it just coincidence? Am I simply attuned to seeing reflections of Turing in the world because of working on this blog? I think it is coincidence, and I am attuned in that way, but I suspect that it’s more than that.
I think Turing’s prescience — his ability to form important questions (and hypotheses about the answers to those questions) well in advance of the rest of us — means that his relevance becomes increasingly obvious over time. If I were writing a blog about a prominent alchemist I doubt I would come to see reflections of their theories as prominently in the world around me.
In 1873 Arthur Rimbaud wrote in Une Saison en Enfer (A Season in Hell) that “[i]l faut être absolument moderne,” that is “one must be absolutely modern.” Alan Turing manages this trick better than just about anyone, perhaps in the company of H.G. Wells (and maybeRay Kurzweill, although more time will have to pass before Ray’s predictive powers can be assessed). Turing was so modern back in 1950, when he devised what we now know as the Turing Test, that he anticipated issues whose dimensions and importance are only now becoming clear to most of us.
All of which leads me to “Milo,” whose TED videos I recently stumbled across. Milo is a homo artificilialis created by researchers at Microsoft as a means of allowing games to be more realistically interactive. His image lives on a screen which you observe, but he’s watching you through a camera as well. His inner workings incorporate elements of artificial intelligence that allow him to react to your body movements, facial expressions, tone of voice and other signals, and in turn control not only his body movements, but his blush response, the dilation of his nostils, and other subtle aspects of his interaction with his environment, including his reactions to you.
The extremely fine detail of Milo’s perception and display mean that not only can he understand crude inputs like those from a keyboard, but he can perceive you at an unprecedented level of detail, improving the fine grain of his input dramatically. And not only can he deliver gross outputs like speaking and moving his body in large-scale ways that give an impression of life, he can output small-scale details approximating the expression of thought and emotion that will evoke in you unconscious reactions that have previously been impossible for less finely tuned simulacra to obtain. All of this adds up to significantly improved believability — Milo excels at “the imitation game,” Turing’s own term for the procedure involved in the Turing Test (for those unfamiliar with the test, there is more on it below).
This BBC article has an embedded video of Milo, while the video below is more recent and addresses public reaction to the first video.
You can interact with Milo with a degree of realism that other artificial humans can’t approach, but does he pass the Turing Test?
In “Computing Machinery and Intelligence,” [pdf] Turing famously postulated a test in which — to summarize his argument at the risk of doing violence to an elegant thought — a human subject interacts through text messages with two participants he or she can’t see, one being another human and the second being a machine which is to be tested for intelligence. If the subject — who can only interact with the participants through text — is unable to correctly identify which participant is the machine, then the machine can be said to have achieved some measure of intelligence.
In other words, if the machine can imitate an intelligent creature with sufficient believability as to make it indistinguishable from an actual intelligent creature, we should treat it as having intelligence. We may not agree that the inner workings that allow it to appear to be thinking are actually capable of producing real thoughts, but the inner workings don’t matter. In an experiential sense we don’t directly confront the inner workings of our friends or families — we deal with their external signals, like words and gestures — and yet we treat them as possessing intelligence.
So what about Milo? Peter Molyneux, who showed off Milo at TED, says “[m]ost of it is just a trick – but it is a trick that actually works.” The thing is that in the Turing Test, if it works, it works — external functionality is the sole standard by which a prospective thinking entity is measured and “tricks” are irrelevant. One of the fundamental questions underlying the Turing Test is: if something can interact with a person in such a way as to appear indistinguishable from that which we accept as intelligent, on what basis do we deny it the label “intelligent”?
As homo artificialis becomes better at imitating homo sapiens, this question is thrown into greater and greater relief. You and I see it when we look at Milo — Turing saw it in his minds eye at a time when a telephone was a heavy bakelite object tethered to a wall by a cord and a computer was something like ENIAC, which filled a room and weighed 30 tons.
Obviously I see Turing in the world around me because, through his pioneering work in mathematics and computing, he is embodied in that world, but very importantly I also see him everywhere because his almost magically prescient thought makes him more and more relevant as time goes on.
