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From: ISSSSM@NUSVM.BITNET (Stephen Smoliar)
Newsgroups: comp.ai
Subject: RE: UNIFIED MODEL FOR KNOWLEDGE REPRESENTATION? (IMPOSSIBLE
Message-ID: <9106130134.AA24444@lilac.berkeley.edu>
Date: 13 Jun 91 01:34:52 GMT
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In article <1991Jun12.130817.3621@kingston.ac.uk> is_s425@kingston.ac.uk
(Hutchison C S) writes:
>A semantic theory will specify the meanings of well-formed sentences in the
>language.  A semantics built upon a correspondence theory of truth has a
>commonsensical appeal to it: what, after all, are sentences expressing
>propositions about if not about the world in which language users live?
>Conversely, if sentences do not express propositions about the world that
>can be true or false (referring instead, for example, to speakers'
>"perceptions" or internal representations of the world), then how can
>conversants ever know that they are talking about the same thing(s)?  A
>correspondence theory of truth, and a semantics dependent upon it, rescues
>the theory of semantics from the vagaries of 'mentalism' and 'solipsism'
>that Stephen Smoliar fears.
>
I am willing to accept that mentalism bring along some vagaries which we would
like to avoid, but the only reason I was sounding apologetic about solipsism is
that I suspect it is not as bad as we have been conditioned to believe.  Long
before he began to develop his work on situated automata, Stan Rosenschein was
entertaining the possibility that solipsism had a legitimate role in artificial
intelligence;  but back in those days it was still fashionable to poke fun at
Bishop Berkeley.  Now that we are beginning to get a handle on situated
reasoning and build systems which can actually engage it, I see no reason
to "fear" solipsism.  Rather, it may rescue us from all the corners in which
we keep painting ourselves with our obsessive belief that "knowledge
representation" has something to do with that knowledge we engage to
get along in the world.  Let us try to pursue this point a bit further:

>  Now let's
>assume that the greater part of what I or anybody else knows is knowledge
>derived from text (e.g., I know that Bogota is the capital of Columbia because
>I have read it; I have never been to Columbia to check; perhaps Bogota doesn't
>even exist).

I shall grant you this assumption even though I disagree with it.  When you get
too wrapped up in text, you tend to dismiss all the things you know that are
NOT derived from that source (such as how to tie your shoes, how to cross a
busy street, and probably even how to get to work in the morning).  I would
further argue that it is all this non-text knowledge which we never even
consider articulating in text which is REALLY the "greater part" of what
anybody "knows."

>  What do readers of each of the four sentences [the four headlines about an
> African event] know?  'Know' is
>a factive verb; does this then fall short of a bona fide sense of knowledge?
>Does the reader of headline 1 know the same things as the reader of headline
>4?  If the first and last sentences both express partial truths, why do I
>find it hard to persuade my fellows that the last headline represents
>knowledge of the world every bit as much as does the first headline?  How is
>the knowledge that I and my fellow newspaper readers extract from text
>integrated into what I and they know already?
>
Basically, I would argue that you are trying to make your point by asking a lot
of ill-formed questions!  It is not the QUANTITY of your questions that matters
but rather their QUALITY!  Rather than ask what a reader "knows," I would
argue that you should be asking how that sentence impacts his behavior.
At this point, you have to recognize that there is no such thing as a "generic"
reader.  You can only ask about the behavior of a flesh-and-blood (so to speak)
INDIVIDUAL, rather than an abstract sentence processor.  For example, for an
international trader, "knowledge" is going to have to do with doing business
in Africa.  If he has an office in Salisbury, he probably has to entertain a
decision to shut that office down and evacuate his personnel.  On the other
hand, a white middle-class reader in a relatively quiet town might start
reflecting on his attitude towards the blacks who moved in down the lane,
realizing that he has been unconsciously crossing to the other side of the
street whenever he sees them.  We are not talking about text-based propositions
which are true or false here.  We are talking about making decisions in the
real world--a form of knowledge which, I believe, Donald Schoen has come to
call "knowledge-in-action."  (Since my books are still in transit, I may need
to be corrected on this.)  My sincere advice to you, Chris, is to get yourself
a better set of questions before you proceed any further!

>Here is an example form Carbonell (1981):
>
> Soviet-backed forces are scoring rapid gains against the Bhutan
> government.  The US is diverting tanks and M-16s, ear-marked for
> the US army, in an emergency airlift to Bhutan.
>
>Carbonell indicates the different responses that the report (or, in his words,
>"event") would elicit from a "US-liberal" and a "US-Conservative".  Clearly
>other responses would be elicited were the report worded differently.  Here
>are some of my versions:
>
> Rebels' advance against government forces prompts US airlift of
> emergency arms package to Buthan.
>
> US pumps arms into Buthan as the Washington-backed regime loses
> ground to people's army.
>
> Buthanese people's gains in struggle to liberate homeland spark
> panic bid by US imperialists to bolster beleagured puppet
> dictatorship.
>
>Are the reports talking about the same event?  If so, the reports are either
>true or false, and there should be ways of determining the truth value of
>the propositions expressed.  If the reports represent merely the contents
>of 'perceptions' or 'interpretations', then how can we ever know that we
>are talking about the same things? (or: how can we be sure that we are
>talking about the real world at all, and that therefore there is any physical
>circumstance that can in principle decide the issue?)
>
In this case I feel I can give you a straight answer:  We can't!  This is not
as horrible as it may seem at first blush.  There are very few absolute
conclusions we draw as we go around in the world.  Our "intelligence" (whatever
that means) does not reside in our ability to determine the true of
propositions but in our ability to adapt to changing positions in the
conclusions we draw and the decisions we make.  Much of dialog is actually
a matter of dealing with the fact that two people are not really "talking
about the same things."  Since they still have to deal with each other, dialog
becomes a tool for resolving matters;  but there is never any ABSOLUTE
resolution.  Rather, there are these continuous streams of behavior.
Were those streams not properly mediated, we would not be able to survive
in this confusing world.

===============================================================================

Stephen W. Smoliar
Institute of Systems Science
National University of Singapore
Heng Mui Keng Terrace, Kent Ridge
SINGAPORE 0511

BITNET:  ISSSSM@NUSVM

"He was of Lord Essex's opinion, 'rather to go an hundred miles to speak with
one wise man, than five miles to see a fair town.'"--Boswell on Johnson