The Turing Test (discussed in the previous section) was the first attempt at resolving the question of machine intelligence. It was a behavioural test, judging intelligence based not on inner processes, or faithfulness to neuronal structure, but purely on a computer's ability to verbally communicate. This approach elicited numerous objections: Why should behaviour be the final test on intelligence, hadn't psychology moved away from behaviorism? How can behavior suffice if the internal mechanisms controlling it are nothing like a human being's? How can a conversation capture all of human intelligence? These questions essentially reduced themselves to the question of whether one could pass the Turing Test, that is, produce passable conversational speech, while still possessing no 'real' intelligence. This argument has been stated in numerous ways, but perhaps none more eloquent than John Searle's Chinese Room metaphor.The Thought Experiment (An Adaptation of Searle's Original)
Searle asks the reader to imagine a room, with a man trapped inside. The man speaks no Chinese, nor could he even confidently distinguish Chinese characters from random lines of similar structure. One day, as he is sitting in the room, someone slips a piece of paper under the door with (what he assumes to be) Chinese writing on it. Having puzzled over it for a moment, he notices that there is a book in the room titled "What to do if someone slides some Chinese writing under the door." Having nothing better to do, the man proceeds to open the book and begin reading. The book, he finds, is actually an enormous set of instructions for producing new Chinese symbols based on what comes in. The rules instruct him on how to produce new Chinese symbols, based on the ones received. They are all if-then type statements describing a pattern in the text and the appropriate action or response. He follows these rules, using the piece of paper handed to him, and produces a new sheet, which he slides back under the door. The next day, another sheet comes in, he again opens the rule book, finds out which symbols to write and in which order, and passes the completed sheet back out. At no time does the man understand what he's doing as anything more than symbol manipulation, he does not understand the words coming in, or the words going out, he isn't even sure they ARE words - but it's more exciting than doing nothing, so he continues. What the man in the room does not know, is that the symbols coming in are questions, written in Chinese, and that the symbols he produces in turn are answers to those questions. What's more, the book of instructions has been written so well that his answers are not only proper Chinese, but they make sense, and are indistinguishable from an actual Chinese speaker. Outside, the world is amazed that this room can actually understand Chinese, that the room is intelligent. Inside though, we know that the man understands no Chinese whatsoever!The Conclusion
What Searle describes is a system that produces intelligent, meaningful output, in the absence of true understanding. If you accept this counter-example, then the Turing Test is doomed. The Chinese Room would pass the Turing test, even though it lacks understanding and intelligence. Searle's argument has, naturally, produced its own share of furious debate, and several strong counter-arguments have been levelled at it. The adaptation presented here is meant to familiarize students with the ideas Searle is trying to convey, but the thought experiment and the debate surrounding it deserve a more thorough analysis. Thus, two readings are provided for further elaboration of the argument and its replies.