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Re: Some TAG review of "Cool URIs for the Semantic Web"

From: John Cowan <cowan@ccil.org>
Date: Thu, 20 Sep 2007 17:59:04 -0400
To: Pat Hayes <phayes@ihmc.us>
Cc: John Cowan <cowan@ccil.org>, Technical Architecture Group WG <www-tag@w3.org>
Message-ID: <20070920215903.GP26549@mercury.ccil.org>

Pat Hayes scripsit:

> Quine is one of my heroes also. Do you have a citation for the above?

_Quiddities_, I think.

> Then let us be honest about this. When I am thinking of unicorns,
> there is in fact nothing I am thinking *about*.

That is exactly right.  There is no *thing* you are thinking about.

> There are concepts of unicorns, thoughts of unicorns, and so on; and
> even (if one is willing to stretch ones ontology this far, which in
> fact I am, though many are not) *possible* unicorns; but there are
> no unicorns.

So far so good, although I think you can make a case that there are
no possible unicorns: that at most, it is possible that there might
exist something we'd call a unicorn, but unicorns-as-we-know-them can't
possibly exist.  But that is neither there nor here.

> It is impossible to talk *about* unicorns. The use of unicorn-talk
> (as Quine might have put it) is either non-referential, or must be
> understood as referring to something else.

Now I think this inference is entirely unwarranted.  You can't *point* to
unicorns, either physically or verbally, so there are no *references* to
unicorns.  But unicorns are a perfectly legitimate subject matter; I could
discourse about them for quite a while.  By the same token, I could also
talk about my or your or So-and-so's thoughts or concepts of unicorns,
but then I would say different things from what I would say when I talked
of unicorns, as it were, themselves.  (Die Einhorn-an-und-fuer-sich?
Probably not.)

At most this is a bad pun on "about".  _The Hobbit_, for example, is about
Bilbo Baggins, although there is no Bilbo Baggins for it to be about.
Nor is it about Tolkien, or Tolkien's mind, though there are other books
that are about those subjects.  I don't find this at all paradoxical.

> >Not at all.  The referent of the word "unicorn" is unicorns.

> No, it is not, since (as you have agreed) there are no unicorns to be
> such referents. You really cannot have it both ways.

Yes, that was sloppy of me.  I should have said that when I use (as
opposed to mention) the word "unicorn", my subject matter is unicorns.

> In order to talk about unicorns, you have to admit them into some kind
> of at least logical existence.

You woefully underestimate the reach of the imagination.  I can make
even square circles my subject matter, though they don't exist in
*any* possible world, never mind this one (as Carnap said when
Smullyan showed him a card trick).

> . What you are referring to by the use of "unicorn" might be possible
> unicorns, or ideas of unicorns, or legendary unicorns, or unicorns in
> an imaginary world: but most assuredly not unicorns.

I think I'll stick to saying that my subject matter is unicorns, and
that the word "unicorn" doesn't refer.

> >-- any more than when I talk of having a heart (physical,
> >non-metaphorical) I am talking of having a liver, even though {X|X
> has >a heart} and {X|X has a liver} turn out to be the same sets.

> ? That wouldn't follow at all. At best, strict extensionalism would
> tell you that liver-havers (things that have livers) are the same
> things as heart-havers. Which of course they are.

The point of my analogy was that talking about unicorns is not the
same as talking about purple (by nature, not by paint) rhinos, though
both constitute the members of the same set (the empty one).

John Cowan    cowan@ccil.org    http://ccil.org/~cowan
        Sound change operates regularly to produce irregularities;
        analogy operates irregularly to produce regularities.
                --E.H. Sturtevant, ca. 1945, probably at Yale
Received on Thursday, 20 September 2007 21:59:16 UTC

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