After a bout of intense work that consumed the Christmas season, I decided to take a busman's holiday and have some fun with my computer. The inspiration was The Policeman's Beard is Half Constructed, a book that Geri Younggren showed me at Apple Computer. This book purports to be the first literary work written entirely by a machine.
[quoteright'/>I had assumed that computer-generated prose would necessarily be trite and simplistic. But this work was filled with deep mutterings about the meaning of life as well as off-the-wall comments on such subjects as lettuce and lamb chops. A short description in Scientific American confirmed that RACTER, the program that wrote it, had been evolved over several years into a rat's nest of parsing algorithms, inflective tables, and recursive functions. Complex program, complex output.
But this set me thinking. Alan Turing once suggested that we could determine whether or not a machine was intelligent by hooking it up to a telex circuit. If a human operator conversing over the circuit could not tell whether he was talking to a machine or to another person, then we would have to call the machine "intelligent. I have always suspected that such an "interactive test is too subjective, since a clever examiner could make a machine sound human (or a human being sound mechanical) by choosing suitable questions. A better test would be to ask the machine to create essays on various subjects, then judge them on their content. By this standard, was RACTER approaching artificial intelligence?
The answer is no. The rock on which the quest for artificial intelligence always breaks up was also defined by Turing; it is the "Turing machine." The operation of every computer, no matter how complex its hardware or software, can be equated to a sequence of operations performed by a Turing machine. And such a machine is stubbornly deterministic: its next act is always predestined by its state at a given moment. You know just by looking at it that a Turing machine can never become intelligent.
But wait! say the AI researchers: we use random functions and fuzzy logic; we interrupt the Turing machine's lockstep. Yet do they interrupt it in a constructive way? Random input to a computer program is no different in form from any normal data input. From a computer's "viewpoint," random numbers are indistinguishable from numbers typed by an operator at a keyboard. They are equally "meaningless" in contrast to the "meaningful" numbers (addresses, pointer values, intermediate products, etc.) that the computer generates internally. But from a human viewpoint, random numbers are less meaningful than operator inputs. Hence introducing them into a program in order to free it from Turing machine determinism is a movement away from intelligence.
So I sat down at my Apple III, my fingers moving idly o'er the keys, and came up with a program I call PROSEWRITER. Its algorithm is simple. It operates on a file of language matrices that represent English sentences and parts of sentences. Whatever it finds in lower case letters goes directly to the output; whatever is in capitals is a "classifier" that points to a group of other matrices. It picks a matrix at random from the indicated group and inserts it into the output. Thus, for example,
let's eat a NOUN might become let's eat a banana
George Towner was born in Reno and grew up near Berkeley. As a teenager he began making gangster movies using an old 8mm camera, one of which featured a car being pushed over a cliff off State Highway 1. He has started and sold two successful technology firms, and currently works for Apple Computer, where he is the most senior in age. He lives with his wife in Sunnyvale. They have two daughters and a son.
|E-mail Print Blog|