- 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