Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!iuvax!cogsci!dave From: dave@cogsci.indiana.edu (David Chalmers) Newsgroups: comp.ai Subject: Re: No more Chinese rooms, please? Message-ID: <50741@iuvax.cs.indiana.edu> Date: 13 Jul 90 04:57:31 GMT References: <25422@cs.yale.edu> <593@ntpdvp1.UUCP> <31329@cup.portal.com> <597@ntpdvp1.UUCP> Sender: news@iuvax.cs.indiana.edu Reply-To: dave@cogsci.indiana.edu (David Chalmers) Organization: Indiana University, Bloomington Lines: 118 In article <597@ntpdvp1.UUCP> kenp@ntpdvp1.UUCP (Ken Presting) writes: > >> Tom Blenko writes: > >> FORALL P EXISTS M NOT(M(P) ==> M(P) is intelligent) > >Notice that for Searle to support this last claim, he needs to demonstrate >the existence of a single Machine such that no matter what Program it is >running, it will not understand Chinese. Just for the record, this is fallacious. Such a strategy would be sufficient to support the claim, but not necessary. Take another look at the order of the quantifiers. Talk of "machines" tends only to confuse the issue, anyway. All we need is the notion of *program* (a formal object), and *implementation of program* (a physical system). It's not clear that all implementations will be describable as running on pre-existing machines. In this framework, the strong AI claim becomes: EXISTS P (program) such that FORALL S (physical system): S is an implementation of P => S is intelligent. Actually, even this may be too strong. Some might like to say "S produces intelligence" rather than "S is intelligent" -- the question of the "ownership" of the intelligence is somewhat vague. e.g. is your *brain* intelligent?; is your *body*?; such technical questions don't need to be answered to deal with Searle's argument. Anyway, with this in place, Searle needs to show FORALL P, EXISTS S such that S is an implementation of P but S does not produce intelligence, which is what the Chinese Room purports to show. Of course it doesn't show that, but that's another story. Suffice to reiterate the often-made point that the fact that the pre-existing machine (i.e. the person in the room) that implements the program fails to understand is quite irrelevant. Implementing machines aren't what counts: implemented systems are. >program, then he can conclude for all machines that there is no necessary >connection between the program it runs and its understanding. Searle thinks >this assumption follows trivially from "Axiom 1: Programs are purely formal". >Pat Hayes denies the assumption (with some justice, I think, but the issue >is not simple). Actually, I think that programs are indeed purely formal (or purely syntactic, or whatever you like). However, *implementations of programs* certainly aren't. They're concrete physical systems with all kinds of interesting internal causal structure. The fallacy of "programs are purely syntactic, minds are semantic, syntax isn't sufficient for semantics; therefore implementing an appropriate program cannot be sufficient to produce a mind" argument is best brought out by a corresponding argument: (1) Recipes are completely syntactic. (2) Cakes are tasty (or crumbly, or heavy, or...) (3) Syntax is not sufficient for tastiness (or crumbliness, or heaviness...) (4) Implementing the appropriate recipe cannot be sufficient to produce a cake. I hope that even Searle would see the fallacy here. Recipes are syntactic, but *implemented recipes* are not. Of course, one needs a meaningful interpretation procedure to go from the recipe (formal specification) to the cake (physical implementation). But one has such a procedure (it's hanging around in the head of (good) cooks, and could presumably be mechanized.) Exactly the same goes for programs. Programs are syntactic, implemented programs are not. Implemented programs are physical systems, derived from formal programs through an interpretation procedure (either a compiler or an interpreter, in practice, or both.). The role of the compiler/interpreter is precisely analogous to the role of the chef. >Now, you may object that if the question "What program is that machine >running?" is not enough to decide the issue of the machine's intelligence, >then no amount of additional information could ever establish that a >general-purpose computer is intelligent. Many people do believe this >(the Churchlands seem to), and propose that Connectionism is the only >hope of AI. This statement seriously misconstrues the nature of connectionism. The issue of Connectionism vs. Traditional AI is quite orthogonal to the issue of Strong AI vs. Searle. Personally, I'm a dyed-in-the-wool connectionist (or, more generally, a subsymbolic computationalist), but I'm also a dyed-in-the-wool Strong AI supporter. The two positions are quite compatible. Most connectionists believe that implementing the right program is enough to give you intelligence -- they just happen to believe that the program you need will be of a particular kind, compatible with the principles of connectionism. The notion that connectionism rejects, say, the Turing notion of computation is quite prevalent in some circles, and can even be found in print from time to time. It's quite fallacious, though. Personally, I think that the Turing notion of computation is the greatest thing since sliced bread. It's just that people in traditional AI placed far too heavy a restriction on the kind of computations they allowed in (by making a deep prior commitment about the ways in which computational states could carry semantics). Connectionism advocates removing this heavy semantic commitment (note: it doesn't advocate removing semantics, it just remains silent about the level at which the semantics might lie), and thus returning to the full-fledged, unrestricted class of computations that Turing allowed. Most connectionists believe in Strong AI, without a doubt. Only the *class* of sufficient programs is in dispute. Sorry about this... and I had vowed "never again". Chinese-Room withdrawal symptoms, I guess. One of these days I'm going to write a paper called "Everything You Wanted to Know About the Chinese Room but Were Afraid to Ask". Searle's arguments are deeply fallacious, but they raise an enormous number of interesting issues. -- Dave Chalmers (dave@cogsci.indiana.edu) Concepts and Cognition, Indiana University. "It is not the least charm of a theory that it is refutable"