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Re: [ontolog-forum] Aunt Jane (was Layer Cake)

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>, Gary Berg-Cross <gary.berg-cross@xxxxxxxx>
Cc: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Kathryn Blackmond Laskey <klaskey@xxxxxxx>
Date: Thu, 02 Aug 2007 17:55:20 -0400
Message-id: <p06110429c2d7f5dd6c7c@[]>
Pat,    (01)

>...The Tarskian model-theory view of
>the 'universe of discourse' D as being a set,
>does not imply that the things in that set have
>to be... real... Real,
>unreal, imaginary, Platonic, abstract or physical
>things can all be things in sets.    (02)

Absolutely.    (03)

But this thread started when I said some people object to model 
theory as being too abstract, and you said nothing prevents the 
things in D from being actual real things such as people or horses.    (04)

I agree with you fully on that.    (05)

But my purpose was to note explicitly that a logical theory can be 
about BOTH the real world and a Tarski model, without requiring one 
to believe that the "things" in the Tarski model correspond directly 
to anything real.    (06)

In my attitude example, I can regard the sentence, "Aunt Jane has a 
positive attitude" to be about the real world without accepting the 
claim that there are actual physical or mental "things" that 
correspond in any direct way to attitudes.  I use the shorthand 
"positive attitude" because it conveys to the listener a 
good-enough-for-purpose approximation of what I mean.  But I don't 
really believe Aunt Jane "has" some sort of "attitude-thing."    (07)

There is, however, an "attitude-thing" in the Tarski model, and it is 
associated with an "Aunt-Jane-thing" in the Tarski model.  Pat 
pointed out that there is nothing stopping the "Aunt-Jane-thing" in 
the Tarski model from being my actual in-the-flesh aunt.  However, if 
I don't believe there really are attitudes, then the "attitude-thing" 
in the Tarski model is not a real thing in the world.    (08)

Now let's go back to the question of what my sentence is really about.    (09)

The sentence is about a Tarski model that has an "Aunt-Jane-thing" in 
it (perhaps my actual Aunt Jane), and the "Aunt-Jane-thing" has an 
associated "attitude-thing," and the "attitude-thing" has the 
property of being positive. Because the sentence is about this Tarski 
model, I can apply reasoning engines to it, and derive conclusions 
about the life expectancy of the "Aunt-Jane-thing" in the Tarski 
model.    (010)

The sentence is ALSO about how a very real person -- my mother's 
sister --  thinks, feels, and acts in relation to the world around 
her and the events that occur in her life.  The sentence can be about 
Aunt Jane and her mode of being without requiring me to believe the 
world contains anything that corresponds in any direct way to those 
pesky "attitude-things" in my Tarski model.    (011)

Although I don't buy the assertion that there is a real "attitude" 
that is "possessed" by my Aunt Jane, I do believe that the modeling 
fiction of pretending she "has" an "attitude" corresponds in a rough 
sort of way to reality, in the sense that pretending it is true and 
applying my reasoning engine to the logical theory gives pretty 
accurate predictions about Aunt Jane's life expectancy.    (012)

That's why mathematics works.  It is why most of the time (although 
not yesterday in Minnesota, unfortunately) we can expect the bridges 
not to collapse.    (013)

>So the
>distinction you are drawing here between a set of
>attitudes and a set of real physical things,
>while no doubt important for judging the utility
>or accuracy of an ontology, has nothing at all to
>do with model-theoretic semantics, which applies
>to both of these cases in exactly the same way.    (014)

I wasn't making a point about model-theoretic semantics per se.  I 
was  amplifying of my previous point that a sentence can be about 
both a Tarski model and the real world.  I simply wanted to note that 
a sentence can be (usefully!!) about the real world without requiring 
one to believe that the set theoretic machinery of Tarski 
interpretations is an accurate reflection of how the world actually 
is.    (015)

>...The 'universe of discourse' D... is something like
>the universe that one would have to accept as
>real if one were to take the assertions made in
>the language at face value, as themselves
>veridical.    (016)

Right.    (017)

One can construct theories about D and make effective use of them to 
do things like saving the lives of cancer patients, while also 
regarding them as modeling fictions that are not veridical images of 
the actual world.    (018)

>If my language talks of attitudes,
>then taken at face value it does indeed require
>that the world it describes contains things
>called 'attitudes'. If the real world cannot
>contain such things, then my language is false of
>it; but it might be true of some possible but
>non-actual world.    (019)

If it's a consistent sentence in a logical theory, then it IS true of 
some possible world. The possible worlds of which it is true need not 
be veridical reflections of the real in order for the theory to be 
useful.    (020)

Kathy    (021)

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