Just how smart are humans anyway? Last week's Singularity Summit spent a lot of time talking about the exact point at which computer processing power would match that of the human brain, but that's only the first step. There's the software to make the hardware do stuff, and then there's the whole question of consciousness. At that point, you've strayed from computer science into philosophy and you might as well be arguing about angels on the heads of pins. Of course everyone hopes they'll be alive to see these questions settled, but in the meantime all we have is speculation and the snide observation that it's typical that a roomful of smart people would think that all problems can be solved by more intelligence.
So I've been trying to come up with benchmarks for what constitutes artificial intelligence, and the first thing I think is that the Turing test is probably too limited. In it, a judge has to determine which of two typing correspondents is the machine and which the human, That's fine as far as it goes, but one of the consistent threads that un through all this is a noticeable disdain for human bodies.
While our brain power is largely centralized, it still seems to me likely that both its grey matter and the rest of our bodies are an important part of the substrate. How we move through space, how our bodies react and feed our brains is part and parcel of how our minds work, however much we may wish to transcend biology. The fact that we can watch films of bonobos and chimpanzees and recognise our own behaviour in their interactions should show us that we're a lot closer to most animal species than we think - and a lot further from most machines.
For that sort of reason, the Turing test seems limited. A computer passes that test if, when paired against a human, the judge can't tell which is which. At the moment, it seems clear the winner is going to be spambots - some spam messages are already devised cleverly enough to fool even Net-savvy individuals into opening them sometimes. But they're hardly smart - they're just programmed that way. And a lot depends on the capability of the judge - some people even find Eliza convincing, though it's incredibly easy to send off-course into responses that are clearly those of a machine. Find a judge who wants to believe and you're into the sort of game that self-styled psychics like to play.
Nor can we judge a superhuman intelligence by the intractable problems it solves. One of the more evangelist speakers last weekend talked about being able to instantly create tall buildings via nanotechnology. (I was, I'm afraid, irresistibly reminded of that Bugs Bunny cartoon where Marvin pours water on beans to produce instant Martians to get rid of Bugs.) This is clearly just silly: you're talking about building a gigantic building out of molecules. I don't care how many billions of nanobots you have, the sheer scale means it's going to take time. And, as Kevin Kelly has written, no matter how smart a machine is, figuring out how to cure cancer or roll back aging won't be immediate either because you can't really speed up the necessary experiments. Biology takes time.
Instead, one indicator might be variability of response; that is, that feeding several machines the same input - or giving the same machine the same input at different times - produces different, equally valid interpretations. If, for example, you give a 10th grade class Jane Austen's Pride and Prejudice to read and report on, different students might with equal legitimacy describe it as a historical account of the economic forces affecting 18th century women, a love story, the template for romantic comedy, or even the story of the plain sister in a large family whose talents were consistently overlooked until her sisters got married.
In The Singularity Is Near, Ray Kurzweil laments that each human must read a text separately and that knowledge can't be quickly transferred from one to another the way a speech recognition program can be loaded into a new machine in seconds - but that's the point. Our strength is that our intelligences are all different, and we aren't empty vessels into which information is poured but stews in which new information causes varying chemical reactions.
You might argue that search engines can already do this, in that you don't get the same list of hits if you type the same keywords into Google versus Yahoo! versus Ask.com, and if you come back tomorrow you may get a different response from any one of them. That's true. It isn't the kind of input I had in mind, but fair enough.
The other benchmark that's occurred to me so far is that machines will be getting really smart when they get bored.
ZDNet UK editor Rupert Goodwins has a variant on this from when he worked at Sinclair Research. "If it went out one evening, drank too much, said the next morning, 'never again' and repeated the exercise immediately. Truly human." But see? There again: a definition of human intelligence that requires a body.
Wendy M. Grossman's Web site has an extensive archive of her books, articles, and music, and an archive of all the earlier columns in this series. Readers are welcome to post here, at net.wars home, at her personal blog, or by email to email@example.com (but please turn off HTML).