Re: URI Declarations [Usage scenario 1b]

At 2:36 AM -0500 3/2/08, John Cowan wrote:
>Booth, David (HP Software - Boston) scripsit:
>
>>  Although I agree with some of the sentiment that you express, I don't
>>  know any objective way to differentiate "essential (identifying) claims"
>>  from other claims.  Thus, in some sense the purpose of a URI declaration
>>  is to declare certain claims to be the "essential (identifying) claims"
>>  by fiat.  Using the URI thus implies agreement with them.
>
>Fair enough.  The determination of what is or is not an essential claim
>is a difficult one, but roughly speaking, a property is essential if,
>if it were changed, the object would be a different one altogether.
>For example, I have a father property of Thomas Cowan.  If I were not the
>son of Thomas Cowan, I wouldn't be *me* any more -- I would be someone
>else, or perhaps more accurately, someone else might play the role of me.
>Likewise, Queen Elizabeth has the essential property of being human; if
>she were a swan (that is, always a swan, not a human magically changed
>to a swan), she would no longer be the Queen but some particular swan.
>(These examples due to Kripke.)

And one can give many others, of course. But you are talking about 
essential properties - what in OntoClean are called, if memory 
serves, "rigid" properties. Whereas what David requires us to put in 
our declarations are "identifying" properties, those which are 
supposed to pin down a referent uniquely. These are not the same 
notion. Being human, as a property of a human, is necessary (rigid) 
but it is most emphatically not 'identifying' (until we get the point 
of there being only one of us around.) In fact, necessary properties 
tend to be of the least use for identification, precisely because, 
being necessary, they tend to be shared by everything else in the 
relevant category. If you want to identify me uniquely, you will do a 
lot better knowing my SS number (not essential or rigid in any way) 
than the essential fact that I am human.

Overall, I'd suggest that this entire discussion is so hopelessly 
muddled that the proposal is best dropped before we generate even 
more confusion. At least, lets see some convincing examples of what 
might constitute an appropriate 'declaration' before proceeding. I 
don't think that "identifying properties" exist. Can anyone prove me 
wrong?

Pat

>
>--
>Evolutionary psychology is the theory           John Cowan
>that men are nothing but horn-dogs,             http://www.ccil.org/~cowan
>and that women only want them for their money.  cowan@ccil.org
>         --Susan McCarthy (adapted)


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