Chinese room

From Free net encyclopedia

(Redirected from Chinese Room)

The Chinese room argument is a thought experiment designed by John Searle (1980 [1]) as a counterargument to claims made by strong artificial intelligence (AI, also functionalism). At its base is Searle's contention that syntax (grammar) is not tantamount to semantics (meaning).

Searle laid out the Chinese Room argument in his paper "Minds, brains and programs" published in 1980. Ever since, it has been a mainstay of debate over the possibility of what Searle called 'strong artificial intelligence'. Supporters of strong artificial intelligence believe that an appropriately programmed computer isn't simply a simulation or model of a mind, it actually would count as a mind. That is, it understands, has cognitive states, and can think. Searle's argument (or more precisely, thought experiment) against this position, the Chinese room argument, goes as follows:

Suppose that, many years from now, we have constructed a computer which behaves as if it understands Chinese. In other words, the computer takes Chinese symbols as input, consults a large look-up table (as all computers can be described as doing), and then produces other Chinese symbols as output. Suppose that this computer performs this task so convincingly that it easily passes the Turing test. In other words, it convinces a human Chinese speaker that it is a Chinese speaker. All the questions the human asks are responded to appropriately, such that the Chinese speaker is convinced that he or she is talking to another Chinese speaker. The conclusion proponents of strong AI would like to draw is that the computer understands Chinese, just as the person does.

Now, Searle asks us to suppose that he is sitting inside the computer. In other words, he is in a small room in which he receives Chinese symbols, looks them up on look-up table, and returns the Chinese symbols that are indicated by the table. Searle notes, of course, that he doesn't understand a word of Chinese. Furthermore, his lack of understanding goes to show, he argues, that computers don't understand Chinese either, because they are in the same situation as he is. They are mindless manipulators of symbols, just as he is - and they don't understand what they're 'saying', just as he doesn't.

1 Thought experiments
2 Formal arguments
3 Criticism
4 Related works

[edit]

Thought experiments

In 1980, John Searle published "Minds, Brains and Programs" in the journal The Behavioral and Brain Sciences. In this article, Searle sets out the argument, and then replies to the half-dozen main objections that had been raised during his presentations at various university campuses (see next section). In addition, Searle's article in BBS was published along with comments and criticisms by 27 cognitive science researchers. These 27 comments were followed by Searle's replies to his critics.

Over the last two decades of the twentieth century, the Chinese Room argument was the subject of very many discussions. By 1984, Searle presented the Chinese Room argument in a book, Minds, Brains and Science. In January 1990, the popular periodical Scientific American took the debate to a general scientific audience. Searle included the Chinese Room Argument in his contribution, "Is the Brain's Mind a Computer Program?" His piece was followed by a responding article, "Could a Machine Think?", written by Paul and Patricia Churchland. Soon thereafter Searle had a published exchange about the Chinese Room with another leading philosopher, Jerry Fodor (in Rosenthal (ed.) 1991).

The heart of the argument is an imagined human simulation of a computer, similar to Turing's Paper Machine. The human in the Chinese Room follows English instructions for manipulating Chinese symbols, where a computer "follows" a program written in a computing language. The human produces the appearance of understanding Chinese by following the symbol manipulating instructions, but does not thereby come to understand Chinese. Since a computer just does what the human does — manipulate symbols on the basis of their syntax alone - no computer, merely by following a program, comes to genuinely understand Chinese.

This argument, based closely on the Chinese Room scenario, is directed at a position Searle calls "Strong AI". Strong AI is the view that suitably programmed computers (or the programs themselves) can understand natural language and actually have other mental capabilities similar to the humans whose abilities they mimic. According to Strong AI, a computer may play chess intelligently, make a clever move, or understand language. By contrast, "weak AI" is the view that computers are merely useful in psychology, linguistics, and other areas, in part because they can simulate mental abilities. But weak AI makes no claim that computers actually understand or are intelligent. The Chinese Room argument is not directed at weak AI, nor does it purport to show that machines cannot think — Searle says that brains are machines, and brains think. It is directed at the view that formal computations on symbols can produce thought.

We might summarize the narrow argument as a reductio ad absurdum against Strong AI as follows. Let L be a natural language, and let us say that a "program for L" is a program for conversing fluently in L. A computing system is any system, human or otherwise, that can run a program.

(1) If Strong AI is true, then there is a program for Chinese such that if any computing system runs that program, that system thereby comes to understand Chinese. (2) I could run a program for Chinese without thereby coming to understand Chinese. (3) Therefore Strong AI is false.

The second premise is supported by the Chinese Room thought experiment. The conclusion of this argument is that running a program cannot create understanding. The wider argument includes the claim that the thought experiment shows more generally that one cannot get semantics (meaning) from syntax (formal symbol manipulation).

The core of Searle's argument is the distinction between syntax and semantics. The room is able to shuffle characters according to the rule book. That is, the room’s behaviour can be described as following syntactical rules. But in Searle's account it does not know the meaning of what it has done; that is, it has no semantic content. The characters do not even count as symbols because they are not interpreted at any stage of the process.

[edit]

Formal arguments

In 1984 Searle produced a more formal version of the argument of which the Chinese Room forms a part. He listed four premises:

Premise 1: Brains cause minds

Premise 2: Syntax is not sufficient for semantics

Premise 3: Computer programs are entirely defined by their formal, syntactic structure

Premise 4: Minds have semantic content

The second premise is supposedly supported by the Chinese Room argument, since Searle holds that the room follows only formal syntactical rules, and does not “understand” Chinese. Searle posits that these lead directly to three conclusions:

Conclusion 1: No computer program by itself is sufficient to give a system a mind. Programs are not minds.

Conclusion 2: The way that brain functions cause minds cannot be solely in virtue of running a computer program

Conclusion 3: Anything else that causes minds would have to have causal powers at least equivalent to those of the brain

Searle describes this version as “excessively crude”. There has been considerable debate about whether this argument is indeed valid. These discussions centre on the various ways in which the premises can be parsed. One can read premise 3 as saying that computer programs have syntactic but not semantic content, and so Premises 2, 3 and 4 validly lead to conclusion 1. This leads to debate as to the origin of the semantic content of a computer program.

[edit]

Criticism

There are many criticisms of Searle’s argument. Most can be categorized as either systems replies or robot replies.

[edit]

The systems reply

Although the individual in the Chinese room does not understand Chinese, perhaps the person and the room considered together as a system do. Searle’s reply to this is that someone might in principle memorize the rule book; they would then be able to interact as if they understood Chinese, but would still just be following a set of rules, with no understanding of the significance of the symbols they are manipulating. This leads to the interesting problem of a person being able to converse fluently in Chinese without "knowing" Chinese, and a counterargument says that such a person actually does understand Chinese even though they would claim otherwise. A related argument is that the person doesn't know Chinese but the system comprising the person and the rule book does.

[edit]

The robot reply

Suppose that instead of a room, the program was placed into a robot that could wander around and interact with its environment. Surely then it would be said to understand what it is doing? Searle’s reply is to suppose that, unbeknownst to the individual in the Chinese room, some of the inputs he was receiving came directly from a camera mounted on a robot, and some of the outputs were used to manipulate the arms and legs of the robot. Nevertheless, the person in the room is still just following the rules, and does not know what the symbols mean.

Suppose that the program instantiated in the rule book simulated in fine detail the interaction of the neurons in the brain of a Chinese speaker. Then surely the program must be said to understand Chinese? Searle replies that such a simulation will not have reproduced the important features of the brain—its causal and intentional states.

But what if a brain simulation were connected to the world in such a way that it possessed the causal power of a real brain—perhaps linked to a robot of the type described above? Then surely it would be able to think. Searle agrees that it is in principle possible to create an artificial intelligence, but points out that such a machine would have to have the same causal powers as a brain. It would be more than just a computer program.

[edit]

Other replies

Natural language is not just an impulse-response chain of events, but rather an interaction. A person walking out of the Chinese Room must be able to actually understand Chinese if any of the questions posed relate to him. For instance, the answer to the Chinese-scripted question "What is your favourite colour?" can only be given by reference to the person asked. So if the person can answer, then he understands Chinese, if he can't, then even to an outside observer, that person does not speak Chinese.

It can be argued that semantics in any natural language requires a relation of words to objects in the real world. In a Chinese Room, no relation between words or symbols and the real world can be made because there is nothing to relate to within the Chinese Room other than the rules written down.

[edit]