Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!pt.cs.cmu.edu!andrew.cmu.edu!sn13+ From: sn13+@andrew.cmu.edu (S. Narasimhan) Newsgroups: comp.ai Subject: Re: Can Machines Think? Message-ID: Date: 12 Feb 90 05:04:21 GMT References: <1037@ra.stsci.edu> <6902@cbnewsh.ATT.COM> <1995@moscom.UUCP> <4050@jarthur.Claremont.EDU> <907@athen.sinix.UUCP> <1326@oravax.UUCP> <11185@thor.acc.stolaf.edu> <1328@oravax.UUCP>, <14069@s.ms.uky.edu> Distribution: comp.ai Organization: Carnegie Mellon, Pittsburgh, PA Lines: 76 In-Reply-To: <14069@s.ms.uky.edu> > Excerpts from netnews.comp.ai: 8-Feb-90 Re: Can Machines Think? Randy > Appleton@ms.uky.ed (549) > I just read the Jan Scientific American, the one with Searle and so on. > Here is the one burning question I have. I think a satisfactory answer to this > will convince me that Searle is right, and strong-AI is wrong. But until > then, I find Searle's argument to be imprecise gobbly-gook. > What exactly IS the difference between "understanding" and "the formal > manipulation of syntatic symbols"? He uses those two phrases quite alot, > and I think it is this difference that is his main argument. BUT HE NEVER > SAYS WHAT IT IS! ARG! > Well, thanks > Randy Surprisingly, none of the postings on this subject ever dealt with this question directly. However, I believe that a clear distinction exists between symbol manipulation and "understanding". I would say a system "understands" iff , given a certain event in some representation , the system can retrieve from its memory (this can be called the "case-base") a previous event which is "related " to the current event in some way . The case-base is a collection of previous experiences either manually input or acquired thru learning. The above mentioned relation between events can be quite subjective, just like responses to a certain question can be quite subjective. It is possible to design a test , which I call the case-retrieval test, to determine whether a system understands a certain event. Should the system be "intelligent" to "understand" things ? This depends on what we mean by "intelligence". However, it is possible to deal with the question of whether a system "understands" without defining "intelligence". The system ,however, should be able to reason by what is called as the "analogical reasoning" or in general "case-based reasoning". On the other hand, a system which can only manipulate symbols or rather, which can give "good" responses to input symbols need not "understand "at all. On the basis of the above, I agree with Searle that the person in the chinese room need not *necessarily* understand the question. However, I don't agree with him when he says " It is impossible to build an 'understanding' system which manipulates only symbols." Note that he also doesn't define what semantics is . I believe that even semantics is basically a group of symbols. (If interested see my Feb.7 posting in comp.ai titled "Semantics are symbols"). You might wonder on what basis I say that case retrieval is "understanding". I'll give an example. Do you understand "x" ? If no, can you say why you don't understand "x" ? Is it because it is meaningless? But, why is it "meaningless" ? Do you "understand" the following group of symbols : "John walked yesterday." Do you "understand" this : " xyzgf#$ ran yesterday ". Do you "understand" this : " John walked $$3ewr" Do you "understand" this : " John ee##2323 yesterday." Do you "understand" this : " $%#$@ #@@@@ FGGFd " I think you will notice the difference in the degree of your "understanding" the above sentences. For the first one , you were able to retrieve a "complete" case from your memory with respect to object, action ,time etc. However, this is'nt the extreme case. Suppose you had a friend whose name was John and you actually saw him walking yesterday then the above sentence might have retrieved that case. I call this exact matching as "knowing" and the particular case as "knowledge" cf. rules in an expert system. Coming back to the above examples, you'll notice that you understand them lesser and lesser ie., retrieve more inexact cases until you reach the last one where you may not able to retrieve any case at all. You'd say that you don't understand the last sentence completely, but do understand the others partially. Interestingly, note that if you "know" something then you don't require to understand it. For example do you "understand" that 2 X 2 = 4 ? Narasimhan.