Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!caen!umich!sharkey!tygra!dave From: dave@tygra.Michigan.COM (David Conrad) Newsgroups: comp.ai.philosophy Subject: Re: UNIFIED MODEL FOR KNOWLEDGE REPRESENTATION? (IMPOSSIBLE Message-ID: <1991Jun19.103728.5004@tygra.Michigan.COM> Date: 19 Jun 91 10:37:28 GMT References: <25348@samsung.samsung.com> <1991Jun14.111857.7374@kingston.ac.uk> Organization: CAT-TALK Conferencing System, Detroit, MI Lines: 126 In article <1991Jun14.111857.7374@kingston.ac.uk> is_s425@kingston.ac.uk (Hutchison C S) writes: > >This may seem old-fashioned, but I am of the opinion that words have meanings >which are public and publicly observable. Informally, those meanings are given >in dictionaries.... >I assume there are necessary and sufficient conditions for someone >being a racist.... > We're dealing with slippery slopes here; is a person who believes that there are no intrinsic differences between ethnic groups and who is opposed to affirmative action programs a racist? This is a question without a right answer. > >"unicorns, Sherlock Holmes" and such like exist; it just so happens that (so >far as I am aware) they don't exist in the *actual* world. > Consult the publicly observable meaning of the word 'exist' in any convenient dictionary; your use of it differs greatly from mine. > >Finally, with regard to your last paragraph, if two people are never really >talking about the same things, then they can never come to any agreement about >the same things (since there are no such 'same' things to agree about). If you >are right (as you may be), then I marvel that people ever manage to >co-operatively get anything done in the world. It may be that people simply >behave *as though* they were talking about the same things; this opens up >quite another can of worms (what is the ontological basis for this >"as-though-ness"?) > As I've tried to point out in two previous postings, *one* person can never be certain exactly what real object she is referring to, or even if there *is* any real referent, so how could two people ever even hope to be certain that they are discussing the same thing. However, people can have degrees of certainty etc. And when the degree is so great that they don't bother to worry about the case where they are talking about different things, then yes, they do "behave *as though* they were talking about the same things...." We probably have a host of mechanisms for deciding identity. Same proper noun, e.g. "Eiffel Tower", "Patrick Swayze". A description of a sensation which matches a sensation in our memory, e.g. "that sickening twisting feeling in your gut just as an elevator starts to descend". Someone appearing to point at a certain thing. I imagine a Minsky-style society, an identity agent with one sub-agent which matches current sensations with remembered sensations (when one wants to know if oneself is referring to the same thing as at a time in the past, e.g. "is this the person I met yesterday"), which would probably be a complex hierarchy itself, with many specialized agents (perhaps one agent just for matching human faces). It would have other sub-agents like proper noun matching (connected to language), sensation-description matching (connected to language and imagination), and "being pointed at", for lack of a better term. These would, of course, have to work together in many cases, e.g. pointing and sensation-description "the brown one over there ". This identity agent would return a "likelyhood that two things are identical to the agent which activated it. > >I feel slightly more sympathetic (but only slightly) towards Marvin Minsky's >contribution to the debate.... > >But I rather think that to focus attention exclusively on "internal models" >is to dodge the issue. The example I like is that of a filing cabinet. When >I use the expression "filing cabinet" as a referring expression, I intend to >pick out for my hearer something more than a metal container, around 4ft 6in >high, with a small number of moving parts. What I mean by "filing cabinet" >includes assumptions I have about its functionality, about practices of >producing and storing textual documents, about the history of such practices >within my culture, and about the graphemic storage and retrieval of >information. I do indeed have an "internal model" of a filing cabinet, and I >take it that my having such a model is a necessary condition for my being >able to use the expression as the content of a referring act. I just happen >to espouse a version of realism that allows the world to be populated with >filing cabinets (and other things like chairs) in the rich sense I outlined >above. The internal model that I have of a filing cabinet (or of a chair or >of whatever else) is derivatve and dependent on the existence of filing >cabinets of just this kind 'out there' in the world. It is by virtue of its >existing independently of any internal model that I (or anybody else, correct >or incorrect) may have of it that I can unproblematically refer to a filing >cabinet and feel confident that my hearer knows exactly what it is that I am >talking about. If my hearer gets it wrong, that's his/her problem, and I can >put him/her right. > But aren't your "assumptions...about its functionality" part of your "internal model of a filing cabinet"? Furthermore, my internal model is not "dependant on the existence of filing cabinents ... 'out there' in the world." I can have an internal model of all kinds of furniture just based on drawings and descriptions of them. I can have an internal model of some new kind of furniture which has only been drawn on a drafting board, and there is no actual instance of it extant anywhere in the world. And how does the existance of filing cabinets (I will allow that they exist) give you any confidence that your "hearer knows exactly what it is that [you] are talking about"? What if your hearer is ignorant of filing cabinets? But my main problem is with the idea that an internal model can be seperated neatly into physical and functional components. I doubt that it is possible to think about the form of a filing cabinet without its function being also summoned to mind. I believe that the form and function of objects are connected in mental models of them. > >Now back to my "rioting blacks"/"racists"/& cet problem. I assume there is a >real world out there in which things like "riots", "police", "racists", and so >on, are possible objects. The question again is: are reports of events which >include such terms capable of being true or false? (I think they are.) If >so, how can conflicting reports be true at the same time? Otherwise, if >not, why not? > How many people acting violently make up a riot? How sever/general must a persons feelings about race be to make a racist? These are slippery slopes, subject to personal interpretation. Your rioter may be my protester, or vice versa, and only statements which can be interpreted the same by all can be classified definatively as true or false. You think that reports containing highly subjective statements are capable of absolute truth or falsehood, I do not. David R. Conrad dave@michigan.com -- = CAT-TALK Conferencing Network, Computer Conferencing and File Archive = - 1-313-343-0800, 300/1200/2400/9600 baud, 8/N/1. New users use 'new' - = as a login id. AVAILABLE VIA PC-PURSUIT!!! (City code "MIDET") = E-MAIL Address: dave@Michigan.COM