Re: Models Err

Chris Menzel <>
From: Chris Menzel <>
Message-id: <>
Subject: Re: Models Err
To: (Fritz Lehmann)
Date: Sun, 23 May 1993 20:44:24 -0500 (CDT)
Cc: interlingua@ISI.EDU
In-reply-to: <> from "Fritz Lehmann" at May 17, 93 02:49:11 pm
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> 	Sowa argued to Hayes and Schubert that KRep 
> languages describe a model which is not the real 
> world itself.  One proof that a model is not the 
> real world itself is its capacity for error.  A 
> Tarskian model can itself be WRONG.  It can include 
> Pat Hayes among U.S.  Presidents.  (The real world 
> itself cannot err this way.)  The model theoretic 
> evaluation of a KRep assertion may be flawless and 
> yield "T"; that alone does not make it true --- in 
> addition the model must be accurate.  Some errors 
> do not arise in the sentence syntax nor in the 
> model-theoretic evaluation.  The assertion is "true 
> in the model" but false.  Since a model may err, a 
> model is not the world.  Pretty simple, but 
> evidently disregarded by persons overly steeped in 
> the technical formal method (and maybe the 
> notation).  

I don't believe Pat et al. were quite as led astray by formal methods
as you suggest.  Pat is surely aware of the possibility of convoluted
Tarskian models of the sort you discuss.  The important point for him
is that you can also define "accurate" or "intended" models out of
real world objects and thereby provide a rigorous account of how
models represent.  John argued in response for the much stronger claim
that one cannot properly form mathematical models out of real world
objects *at all*.

Chris Menzel
Philosophy, Texas A&M