Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!utgpu!water!watmath!clyde!masscomp!ulowell!apollo!laporta From: laporta@apollo.UUCP Newsgroups: comp.ai Subject: Re: The symbol grounding problem: "Fuzzy" categories? Message-ID: <360e7070.c449@apollo.uucp> Date: Tue, 14-Jul-87 11:37:00 EDT Article-I.D.: apollo.360e7070.c449 Posted: Tue Jul 14 11:37:00 1987 Date-Received: Thu, 16-Jul-87 01:39:39 EDT References: <764@mind.UUCP> <768@mind.UUCP> <770@mind.UUCP> Reply-To: laporta@apollo.UUCP (John X. Laporta) Organization: Apollo Computer, Chelmsford, MA Lines: 81 In article <245@uwslh.UUCP> lishka@uwslh.UUCP (Christopher Lishka) writes: >Given that a dictionary is a descriptive >tool that seeks to give a good view of a language as it is currently being >used, can it really be used as a final authority? My feeling is no; SUMMARY (1) You are absolutely right. There is no 'final authority' because language changes even as one tries to pin it down, with a dictionary, for example. (2) AI programs designed to 'understand' natural language must include an encyclopedic as well as a lexicological (dictionary) competence. (3) The nonexistence to date of perfect artificial understanders of natural language should not be surprising, given the enormity of the task of constructing an artificial encyclopedic competence. (4) The encyclopedia in this instance must grow with the language, preserving past states, simulating present states, and predicting future states. ELABORATION Tackling (2) first: While dictionary definitions are helpful guides in some respects, the nature of linguistic competence is encyclopedic rather than lexicological. For instance, you might hear someone say: Because I was going to give a cocktail party, I went to the mall to buy whiskey, peanuts, and motor oil. A lexicological competence would deem this sentence grammatical and unremarkably consistent, since 'mall' includes the availability of all the items mentioned. An encyclopedic competence, on the other hand, would mark this sentence as strange, since 'motor oil' is not a part of 'cocktail party,' unless, I suppose, you were willing to assume that some of the guests needed mechanical, not social, lubrication. Even this conjecture is unlikely, however, because 'cocktail party' includes humans consuming alcoholic beverages. A case of Billy Beer at the local Exxon is not a cocktail party. Car mechanics do not come to work in little black dresses. An encyclopedic competence is able (a) to isolate the assumptions an utterance requires for coherence, (b) to rank their probability, and (c) thus to evaluate the coherence of the utterance as a whole. Further, 'encyclopedic' in this context includes more than is found in the _Brittanica_. A humorist might write (in the character of a droll garage mechanic) about a parley to negotiate sale of a gas station. He decides to provide a little festive atmosphere by bringing along some beer. But even this hypothesis doesn't eliminate all strangeness: why is the mechanic buying motor oil at the supermarket? Certainly he could get a better price from his distributor. This sentence is a mine of linguistics lessons, but the above should be enough to suggest my point. Encyclopedic competence, however provided, (scripts or semantically marked graphs of words, to give two examples which are not mutually exclusive) is crucial to understanding even the topic of an utterance. The wider question evolves from (1) ... : Language is an elaboration of symbols which refer to other symbols. The 'last stop' (the boundary of semiotic analysis, not the the boundary of the linguistic process itself in actual beings or machines) is the connection of certain signs to 'cultural units.' These pieces of memory are what ground symbol nets to whatever they are grounded upon. (I prefer Harnad's formulation, but that is not crucial for this discussion.) When Og the Caveman remembers one morning the shape of the stone that he used as a scraper yesterday, a cultural unit exists, and stones of that shape are the first signs dependent upon it. To oversimplify, the process continues infinitely as signs are connected to other signs, new cultural units are formed, signs modify other signs, etc. ... and concludes with (3) and (4): Meaning is 'slippery' because language changes as it is used. A historically amnesiac encyclopedic competence for 1980 would mark as improbable sentences used daily at American slave auctions of the 1840's. SOURCE NOTE: Nearly everything I have said here has been elaborated by Umberto Eco in his book 'A Theory of Semiotics' and subsequent writings.