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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.