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From: lee@uhccux.uhcc.hawaii.edu (Greg Lee)
Newsgroups: comp.ai,sci.lang
Subject: Re: Fun with the semantics of paradox
Message-ID: <3242@uhccux.uhcc.hawaii.edu>
Date: 11 Feb 89 12:56:25 GMT
References: <529@aipna.ed.ac.uk>
Organization: University of Hawaii
Lines: 72

From article <529@aipna.ed.ac.uk>, by rjc@aipna.ed.ac.uk (Richard Caley):
\>" "The current king of France is bald."		(1)
\
\>reply in conversations -- to a first rough approximation, a reply
\>must correspond to the main clause in what it is a reply to.
\
\But there _is_ no subordinate clause, unless we introduce one as a
\crowbar to get the facts to fit the theory.

Did I say there was?  (I might resort to a crowbar, but I haven't
yet.)

\...
\Here is a shot at trying to change your mind. ( not original by any
\means ). If (1) is false ( as it must be if it has the meaning which you
\give it ) then, assuming we do not throw out the law of the excluded
\middle, its negation must be true - ie either

Correct.  Its logical negation must be true.  Neither (6) nor
(7) below is the logical negation of (1), however.  Your (7'),
or something along those lines, is the logical negation of
(1).

\	" The current king of France is not bald "	(6)
\
\	" It is not true that the current king of 	(7)
\	  France is bald "
\
\Certainly I would not assert (6). If (7) is true but (6) isn't then we
\must explain why they are not logically equivalent - I think most people
\would say that they were.

Yes, I'd say that, too.

\ On your reading, (6) means
\
\	" There is a unique king of France and he is	(6')
\	  not bald "

Yes.  The negative in the main clause of (6) goes with the corresponding
clause in (6').

\whereas (7) means
\
\	" Anyone who is king of France is either	(7')
\	  not bald or shares the throne "

No, of course it doesn't.  You've made a theory here that putting 'it is
not true that' in front of a sentence (of English) gives its logical
negation, then attributed that theory to me, apparently.  Straw man.

\>The description of such examples in terms of presuppositions and third
\>truth values is a pre-theoretical taxonomy.  It doesn't tell us what is
\>really going on, but just supplies a terminology for enumerating the
\>facts.
\
\Why is this so for presuppositions and third truth values and not for
\syntactic constraints on replies?

Syntactic constraints on replies are there anyhow -- that's just a
fact.  Describing one set of facts in terms of others -- what I
proposed -- is an explanation.  Devising a terminology for some
facts in a way that does not do this -- what you propose -- is
not an explanation.  That's the difference.

\Certainly 3-valued logics can be defined just as formally as syntactic
\constraints, as can rules for deriving presuposition sets from sentences.

I don't see what formalization has to with it.  You don't think that
bad theories are incapable of being formalized, do you?

		Greg, lee@uhccux.uhcc.hawaii.edu