[comp.ai.philosophy] UNIFIED MODEL FOR KNOWLEDGE REPRESENTATION?

ISSSSM%NUSVM.BITNET@CUNYVM.CUNY.EDU (Stephen Smoliar) (06/13/91)

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

sjb@piobe.austin.ibm.com (Scott J Brickner) (06/14/91)

I'm not anything like an expert in AI, or even philosophy, but as an
independent thinker, I've got to poke my nose in here for a second.  The
thread which got us here had some argument about the value of a
knowledge-base that was based only on the subject's "perception" of the
world around him... the question proposed was "How, then, can any two
speakers know that they are speaking about the same thing?"

How, indeed?  This is a VERY fundamental philosophical question... How
do you know ANYTHING?  What does it MEAN to KNOW something?  I think
that thinking too much in terms of an AI knowledge-base leads us
sometimes to forget that they are supposed to be (in some sense) similar
to "natural" intelligences (NI), with our own intelligence being the
only model of such available.  So the first question then, is "What does
it mean to know something?"  One proposed answer is that the ONLY real
facts you know about the universe-of-discourse (universe) is what you
"perceive".  The implication here is that the NI's knowledge-base is
purely his PERCEPTION of the universe.  A corrollary is that it is the
ACT of PERCEIVING that CREATES THE REALITY within the universe.

Two such subjects only know about objects about which they have had
common perception. It is to be hoped that the universe is sufficiently
consistent that there is normally some non-empty intersection between
these two perception sets.  Each intelligence also perceives objects
indirectly, through communication with other intelligences.  Eventually,
a process of abstraction creates an object-image within the knowledge
base of "what everyone knows about such and such".  THIS is how we know
we're talking about the same thing (or at least THINK we are).

So what's the problem?

Sorry if this is somewhat elementary, but it seems relevant to me (i.e.
I perceive it as relevant).

Scott

is_s425@kingston.ac.uk (Hutchison C S) (06/14/91)

In article <1991Jun12.221121.15828@watdragon.waterloo.edu>
cpshelley@violet.waterloo.edu (cameron shelley) writes:
> If you're after *the* truth, then you'll have to provide *the* definitions
> of "riot", "racist", and so on (as I guess John Bradshaw pointed out).  These
> are perceptual, possibly unique categories to each speaker and not things
> you can measure, weigh, or otherwise legitimately encode in a formal
> language---not and capture all the variations involved.  It might be
> tempting to define a 'correct' riot, and then assert others are incorrect,
> but then you've done nothing but become another interpreter with your
> own opinion.

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 (though dictionary writers are, after all, only human and can
get it wrong); more formally, are functions from extensions to possible
worlds.  It is therefore not incumbent upon me to provide the definitions of
"riot", & cet, nor would I presume to pronounce on the correctness of the
definitions of others but would simply refer others to what I take (with
good reason and in the company of many another) to be a proper treatment of
meaning.  I assume there are necessary and sufficient conditions for someone
being a racist much as there are necessary and sufficient conditions for
someone being a policeman; I also assume that the intersection of the
extensions of the two expressions may be non-empty.

> What distinction would a truth-functional theory make between the following
> pair of utterances?
>
>	The cat sat on the mat.
>	The mat was sat on by the cat.

The answer is: none.

> if our communicative apparatus exists just to transmit the
> truth, why do we have more than one token for the same proposition?
> The only explanation comes from considering the speaker's desire to
> emphasize "cat" or "mat" (or conversely de-emphasize the other).  Even
> in a description of an uncontroversial and simple event, point of view
> can play a role.

The propositions expressed by sentences and the use to which sentences are put
are, I think, different issues, the one the concern of semantics, the other of
pragmatics.  Though in the case of the pair of sentences you give, choice
between the two is most likely to be textual (which, of the active and passive
forms, will, in context, produce the more cohesive text?) and thematic (what
is the topic of discourse?)  I can't see this has anything to do with matters
of meaning and truth.

> problem of handling reports about things which don't exist in some way (ie.
> unicorns, Sherlock Holmes, rained-out ball games, etc...).  A paper by
> Hirst I was forced to read lately (on KR of non-existence) suggests just
> going with a naive model.

"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.

> 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!

With your first sentence I agree (almost) entirely.  It is a time-honoured
practice to raise awareness of issues by tossing around a few apt (nb. if
"inexact" rather than "ill-formed") questions.

> 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."

Again, I wholly agree with you that you "are not talking about text-based
propositions which are true or false".  I think you are talking about
something like 'perlocutionary effects'.  Of course the propositions expressed
by sentences will have effects on the behaviour (cognitive or physical) of
hearer-readers.  That is merely a matter of personal psychology, and has
nothing to do with the meanings of expressions, which is what I am concerned
with.

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"?)

I feel slightly more sympathetic (but only slightly) towards Marvin Minsky's
contribution to the debate, which in large part echoes things I've been
thinking (thanks to two books by Jeremy Hayward, entitled, I think, 'Perceiving
Ordinary Magic' and 'Shifting Worlds, Changing Minds') for a long while, viz.

> When you and I both talk about "that
> chair over there", our internal models differ substantially, but not
> enough to make most practical interactions too difficult.  And the
> cchir itself changes imperceptibly from one moment to the next as it
> loses and gains atoms and suffers thermal agitations of its internal
> degrees of freedom.  There is no chair, indeed, from a modern physical
> point of view, only boundaries imposed by observers; my decorator
> friend regards this chair and that other one as a possibly conflicting
> pair, my fried the carpenter sees it as a possibly unsound linkage of
> glue and sticks, and so on.

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.

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?

Chris H

cpshelley@violet.waterloo.edu (cameron shelley) (06/14/91)

In article <1991Jun14.111857.7374@kingston.ac.uk> is_s425@kingston.ac.uk (Hutchison C S) writes:
[...]
>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?

(Assuming your answer to the first question is correct...)

I argue that pragmatics does have a role to play in addressing your
question.  In considering the truth of reports, you must consider why
a speaker might not communicate the truth.  You have been focusing on
inadvertant infelicities alone, but speakers (being agents themselves)
can also lie, that is have reasons to communicate infelicitously.  
Accounting for this requires a model of perlocutionary effects, among
other things.  Since you have dismissed pragmatics and perlocution, you
are denying yourself a criterion for resolving your problem.

(Going back to the first question...)

I agree that the truthfulness of reports is an important question and that
reports can (and should) be judging accordingly.  The pursuit of history is
an example of our interest in the idea.  I think we also agree that "truth"
constitutes a valid relationship between an internal model and perception
of the 'real' world.  However, I don't believe that we can guarantee that
the categorizations we employ in the model itself are valid.  Effective
communication then is only possible with some basic assumptions of common
ground (such as a universal grammar in linguistic theory).

As I indicated, I accept the position that judging the truthfulness of
reports is important and interesting.  I reject the (earlier) implication
that there is an algorithm of establishing such a truth value in the
general case.

				Cam

dave@tygra.Michigan.COM (David Conrad) (06/16/91)

In article <8455@awdprime.UUCP> sjb@piobe.austin.ibm.com writes:
>
>... the question proposed was "How, then, can any two
>speakers know that they are speaking about the same thing?"
>
>How, indeed?  This is a VERY fundamental philosophical question...
>
>[Much about only knowing that which is perceived]
>
>Scott

Bertrand Russell has a fascinating discussion of all this in his book
_The_Problems_of_Philosophy_.  He concludes that we cannot know anything
about objects in the world directly, but only indirectly.  The only things
we can have direct knowledge of are our sensations.   Our knowledge of
objects must always be indirect.  Actually, in addition to our perceptions
we are also directly aware of abstract concepts, which Russell terms
'Universals'.  E.g. I am aware of my sensation of seeing this keyboard
in front of me, and touching it, and hearing the keys click, but I cannot
be *aware* of the existance of the keyboard; I can only infer its existance.
Should I believe that it exists?  Or should I believe it to be a figment of
my imagination?  (I.e. Objective Reality vs. Solipsism.)  Russell concludes
that the consistency of our observations (the keyboard is there *every* time
I look; things simply do not vanish into (or appear from) thin air) suggests
that we should choose, with Occam's razor, to believe that there is indeed
an objective reality, even though we can never experience it directly.

Additionally, we are aware of universals, such as '1+1=2'.  There is no
greater knowledge of it attainable than that which the mind apprehends
immediately.  To use an example which was brought up before, we may doubt
that Bogota is actually the capital of Columbia, or that there is even a
city named Bogota, and we might seek to go to Columbia to see the city for
ourselves.  (We would still have no direct knowledge of Bogota, but our own
sensory perceptions are presumably more trustworthy than our perceptions of
the writing which is supposed to record the sensory observations of persons
not personally known to us.)  But what on earth could it mean to "go and
see the *real* '1+1=2'"?

Back to the question of how two people can know if they are talking about
the same thing, let us take a simple sentence, "There is a man named David
Conrad."  This statement is very different for different people.  I have
direct knowledge of David Conrad.  I am the only person in the universe, 
in fact, who *knows* that the statement is true.  Those with whom I am
acquainted only know of their perceptions of me, from which they infer my
existance.  Most of the rest of you only know of me by description (using
the word 'description' to mean any knowledge gained by language and not
by sensory perception of the object).  So is the sentence the same?
Does it even refer to the same person?  What if you were to discuss this
article with someone, and they were to say, "Oh, I know a David Conrad,"
but it turned out that they only knew someone of the same name?

I think that all that can be said is that a person may think that another
person's description of sensations is consistent with the first persons
sensations, and thus may have been caused by the same object.  When more
information becomes available, either through additional sensations, or
a more specific description of the other's sensations, then the identity
may be reconsidered, either reinforced if the similarity persists, or
dispelled if there is a disagreement ("Oh, the sign was green?  Must have
been a different one than the one I saw, then.").  Knowledge that the
two are referring to the same object must therefore always remain
problematic.  Indeed, it is not possible to say for certain that the
other person even exists.  So the question becomes, "What factors are
used in deciding if a description matches our sensations (or memories
of sensations)."

(I forgot to mention that our memories are also things of which we are
directly aware.  In fact I haven't done justice at all to Russell's
argument, and I suggest anyone who is interested get a copy of
_The_Problems_of_Philosophy_ and read his arguments first hand.)

David R. Conrad
dave@michigan.com
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dave@tygra.Michigan.COM (David Conrad) (06/19/91)

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 <point>".
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
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sarima@tdatirv.UUCP (Stanley Friesen) (06/21/91)

In article <1991Jun19.103728.5004@tygra.Michigan.COM> dave@tygra.Michigan.COM (David Conrad) writes:
>In article <1991Jun14.111857.7374@kingston.ac.uk> is_s425@kingston.ac.uk (Hutchison C S) writes:
>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.

Quite, and this is not even a rhetorical question - such people really
do exist (I can name at least one).

>>"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.

I'm glad someone said this - this business of treating unicorns as existing
in "some" world has always been a sticking point for me with regard to the
"possible worlds" approach to meaning.

[I would say that the word 'unicorn' refers to something that does not exist].

>>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 ...
 
>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...."

Indeed, and I can remember situations where I had a high degree of certainty
that I knew what was being talked about where the other person disagreed
and managed to convince me I was mistaken.

>>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, ...

>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. ...
>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.

And even more.  When I hear or say 'filing cabinet' I usually *start* with
a mental image of my own filing cabinet sitting in a corner at home and ....

I find that all of these diminishing associations are intrinsically bound
up in my mental model of filing cabinets.

>>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.

[And now for the meat].

I think this is really the core of the issue.  Almost all of these terms
are subject to individual interpretation.  For instance the term 'rebel'
may have different referents depending on who is speaking - I see the
definition as being: "Someone in violent opposition to duly constituted
authority".  This makes the term relative to who the speaker considers to
be 'duly constituted authority'.  This is a matter for intense disagreement.
[In the Middle Ages there were two Popes for about a century - the followers
of each considered the other's followers to be rebels - and even today it is
not entirely clear which one was the proper Pope].

So, as to the hadlines quoted, I would say that for all *practical* purposes
they were *all*, in some basic sense, "true".  That is I can come up with
an internal model of events and participants such that various different
observers might *honestly* make all of the statements listed. (That is
the statements would match the definitions in current use by the individual
uttering them).

I think this approach - a sort of contingent, model based approach to
validity (so-called truth) - is a much more useful than trying to apply
a mathematical/logical deductive definition of 'true'.
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uunet!tdatirv!sarima				(Stanley Friesen)