Re: Contexts and quantifiers in KIF

sowa <sowa@turing.pacss.binghamton.edu>
Date: Fri, 16 Apr 1993 11:29:16 -0700
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From: sowa <sowa@turing.pacss.binghamton.edu>
To: Multiple recipients of list <srkb-list@ISI.EDU>
Subject: Re: Contexts and quantifiers in KIF

Jim,

I completely agree with your last note.  A few comments:

> The interpretation I want to give to modal statements 
> is suggested by the operator

>         it is possible for there to be a world such that ...

> which is subtly different from 

>         there is a possible world such that ....

This makes me much happier than some of the previous discussions.
Statements of the form "there is a possible world such that..." are
totally repugnant to me -- primarily because no one has ever given
a plausible explanation for what it would mean to say that a possible
world "exists".  I much prefer the form "It is possible for there to
be a world such that...."  But the indefinite article in front of
"world" still bothers me.  I would be much happier if you would change
that phrase to either of the following forms:

     It is possible for there to be a model of the world such that...

     It is possible for the world to be such that...

The term "a world" still suggests some use of either a metaphor or
a disguised metaphysical assumption.  If by "a world", you mean 
"a model of the world", then I wish you would say so.

> Furthermore, as you rightly notice, I do believe that there are sentences 
> that are true today in this real world that are built from that operator 
> (indeed, from several different flavors of that operator) in which the 
> that-clause will never have been true.

I completely agree with this point.  But you can get all the formal
power you need to make such statements true in a theory that does a
global change of "a world" to "a model of the world".

John