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Re: URI Declarations [Usage scenario 1b]

From: John Cowan <cowan@ccil.org>
Date: Mon, 3 Mar 2008 18:46:19 -0500
To: Pat Hayes <phayes@ihmc.us>
Cc: John Cowan <cowan@ccil.org>, "Booth, David (HP Software - Boston)" <dbooth@hp.com>, "www-tag@w3.org" <www-tag@w3.org>
Message-ID: <20080303234619.GX26125@mercury.ccil.org>

Pat Hayes scripsit:

> (a) I see no reason why essential, as opposed to contingent, 
> properties are important here, and (b) no matter how many you have, 
> you can never get a single referent pinned down.

Au contraire.  A DNA dump plus the time of birth (or even order of birth)
pins down each individual mammal.  (I say "mammal" because eggs might
hatch simultaneously.)  You concede this below.

[snip]

> Or, more to the point, there may be another person who COULD have had my 
> SSN.

That's just why essential properties matter: a contingent property may be
pretty good at identifying, but it can never be definitive.  For example,
the fact that Richard Nixon was president in 1972 is extremely useful
in identifying ("Who is this 'Richard Nixon' of which you speak?"
"The U.S. President in 1972.") but is obviously contingent: Nixon might
have lost, or might have avoided politics altogether.  But if I answer
the question with "The person whose DNA goes ACCACCCATTGGCGTCCGTTT...",
the answer is definitive, because the property is an essential one
(see below), though not nearly as useful.

> > Your DNA dump, though, *is* essential
> 
> Why? Seems to me I could have had different DNA and still have been 
> me. Its too late to change it now, of course.

I believe that's just a fallacy, akin to the Twin Earth fallacy.
You could not have had different DNA and been you, any more than you
could have had a different father and been you, or have been a swan and
been you.  Indeed, these are just more generalized ways of saying you
could not have had different DNA.  Someone else could have been *called*
"Pat Hayes" who was the son (or daughter) of your parents but who
got different DNA from the Sorting Hat, but he wouldn't *be* you, any
more than water can be other than H2O on Twin Earth, though some other
liquid might be *called* "water" there.  Contra Putnam, there simply is
nothing that has all the physical properties of water without being H2O.
(Thus Dennett.)

Likewise, as Kripke says, consider a certain table which is made of wood.
Is it possible that the table, *that very table*, could be made of
something other than wood?  Clearly not: it would be a different table
altogether.  It's possible that *another table which has the function
of that table* might have been made of metal, which is to say that the
existence of that table is itself contingent.  Likewise, your existence
is contingent: the DNA might have sorted differently, in which case you
would never have existed, but someone else would have existed who would
very likely share some of your contingent properties.

> All 'identifying' descriptions are subject to correction like this.

Not so.  "No, I meant quite another organism whose DNA is '...'" is not
subject to correction (except in the sense that I might have blown the
sequencing).  There just can't be two (non-twin) organisms sharing the
same DNA.

> Nice example. I wonder if [the sisters] ever got confused, themselves?

Clearly not, but they have evidence not available to me (such as,
"If there's a pain, it's yours!") to make the distinction with.

> Quine is referring to identity, not identification. All he meant was 
> that you have to be able to make sense of equations: does A=B or not? 

Precisely, but that only means anything if the referents of A and B
can be in some way identified.  Ortcutt = the man in the brown hat.
Of course, one can go too far.  As Norton Juster says:

        Why, can you imagine what would happen if we named all the
        twos Henry or George or Robert or John or lots of other things?
        You'd have to say Robert plus John equals four, and if the four's
        name were Albert, things would be hopeless.

So over-identification is as bad as under-identification: we don't want to
have many distinguishable twos.  This is precisely about identification.

> Identification in the TAG sense is something altogether more than 
> this: it means something social - having a kind of conceptual 
> location in some social space of objects which can be "identified" - 
> and it means being able to get from the 'identifier' to the thing it 
> 'identifies'. None of this is in Quine.

I believe that it implicitly follows from him, but the margins of this
email are too small to contain my proof of this.  :-)

> You had better have a powerful (and universally agreed) set of 
> 'sortal' descriptions available for all contingencies. 

No, I only need a schema for generating them, and I only have to be
as precise as a particular situation calls for.  That is a much less
difficult undertaking.

> And in fact, I bet this wouldn't be considered a proper 
> identifying description in David's sense, in practice. It would be 
> pretty useless in a declaration.

As I noted above, inadequate identifications ("Cicero is a famous orator")
can be extremely useful, and adequate ones extremely useless.

> RDF and OWL already have identity built into their model theories, so 
> we don't need anything new to have that. 

They have formal identity, but not grounded identity, and it's grounding
that we need in order to be talking about anything.  See my previous post.

-- 
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)
Received on Monday, 3 March 2008 23:46:32 GMT

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