- From: John Cowan <cowan@mercury.ccil.org>
- Date: Tue, 28 Jan 2014 21:17:30 -0500
- To: "C. M. Sperberg-McQueen" <cmsmcq@blackmesatech.com>
- Cc: "Henry S. Thompson" <ht@inf.ed.ac.uk>, Paul Grosso <paul@paulgrosso.name>, core <public-xml-core-wg@w3.org>, Tim Bray <twbray@google.com>, Jean Paoli <jeanpa@microsoft.com>
(Note: This whole response is off-topic: any of you may safely ignore it.)
C. M. Sperberg-McQueen scripsit:
> Classing [presupposition failures] as false is a convenient way to
> simplify one's life as someone responsible for having an answer for
> everything (and in particular, responsible for producing a Boolean
> value for arbitrary sentences), but it also gives the account of truth
> and falsehood based on it a certain artificiality [...]
Well, if I rephrase the question "Is 'The current king of France is bald'
true, or is it false?", then I think that even in natural language one
has to reply "False".
> > But even waiving that, I cannot see that a definition of the form >
> "g(x) is true if there exists a y and f(y,x) is true" involves a >
> presupposition at all.
>
> I believe Henry's point is [restatement thereof]. Your not seeing any
> presupposition appears to be just another way of saying you believe that
> "invalid" means "not valid".
My claim is wider than that: that no definition of the above form
contains a presupposition.
> But as an ally of Quine, you must surely be aware that existence
> [and by the same token, non-existence] is not a predicate.
As a Quinian, I am an odd fellow (though not an Oddfellow), for I am also
a Kripkean; as such, I believe that while I am necessarily a person, I am
only contingently a Peircean. (My father Thomas Cowan was a student of
Edgar Singer's, and he was a student of Peirce. So I come by my pragmatism
(or as Peirce called it, pragmaticism) honestly.)
> On the topic of presuppositions: let us assume that your left shoelace
> is not a document with a document type declaration whose constraints
> it satisfies. Does it seem natural to you to say that your shoelace
> is invalid?
No, it doesn't, but I am hard put to it to say why, save
on essentialist grounds. (For my view of essentialism, see
<http://home.ccil.org/~cowan/essential.html>.)
> Part of the problem is that it is not really meaningful to say that a
> document is valid without without reference to some specific document
> type definition (which I will abbreviate in what follows as "schema").
> When we say "document D is valid", I believe we are using a short
> form for an utterance that in fuller form would be "document D is
> valid against schema S", which we can do whenever the identify of
> S is clear from context (as it will be if document D has a document
> type declaration).
Now here I heartily disagree. I think there is a fundamental difference
between schema validity and validity as defined in the XML Rec. The
latter is a two-place relation "document X is valid against schema Y";
but the former, I firmly believe, is a one-place relation "document X
is self-valid"; that is, the declarations in the prolog agree with the
elements and attributes in the body of the document. The fact that the
declarations are often in a separate entity tends to make people think
they are not in the document, but they are.
--
We call nothing profound cowan@ccil.org
that is not wittily expressed. John Cowan
--Northrop Frye (improved)
Received on Wednesday, 29 January 2014 02:17:56 UTC