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From: rjc@aipna.ed.ac.uk (Richard Caley)
Newsgroups: comp.ai,sci.lang
Subject: Re: Fun with the semantics of paradox
Summary: Republicanism and hairdressing again
Message-ID: <529@aipna.ed.ac.uk>
Date: 9 Feb 89 06:01:07 GMT
References: <505@aipna.ed.ac.uk> <3201@uhccux.uhcc.hawaii.edu>
Reply-To: rjc@uk.ac.ed.aipna (Richard Caley)
Organization: Dept. of AI, Edinburgh, UK
Lines: 98
Dragon: Oolong

In article <3201@uhccux.uhcc.hawaii.edu> lee@uhccux.uhcc.hawaii.edu (Greg Lee) writes:
>From article <505@aipna.ed.ac.uk>, by rjc@aipna.ed.ac.uk (Richard Caley):

>" "The current king of France is bald."		(1)

>" I would not say that

>" 	"No he isn't"					(2)

>" Is the natural responce.

>I agree that that is not the natural response.  Neither is "No, there
>isn't." This has to do with syntactic constraints between assertion and
>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. A perfectly respectable
responce ( not a reply, however ) would be

	"but there _is_ no king of France"		(3)

I would never say 

	"No, there isn't"				(4)

would even be a candidate, since (1) makes no _assertion_ of existence,
it just presumes it. 

>If we thus
>distinguish between the sentence *being* false and the circumstances
>that determine whether we can give a *reply* to the effect that it is
>false, we can avoid resorting to a peculiar third truth value (in this
>specific case, anyway).

Ok, I don't like third truth values either, however I don't think that
the way to go is to add more and more complexity to the 'meaning' we
ascribe to an utterance. I don't think that (1) has a meaning in
isolation any more than

	" This is black "				(5)

does. Without knowing what I am pointing at you can neither agree nor
disagree with (5), you can only decide that I am foolish for saying it.

>So, I say, [ (1) ] means the same as "There is a (unique) current
>king of France, and he is bald," but it has a different structure and so
>is not syntactically equivalent in that the two sentences admit of
>different replies.

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

	" The current king of France is not bald "	(6)

or, more conservativly,

	" 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. On your reading, (6) means

	" There is a unique king of France and he is	(6')
	  not bald "

whereas (7) means

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

( I think I have done my rewriting correctly, no doubt someone will
correct me if not ).

Now, I can't give a cast iron proof that (7') is an incorrect reading,
certainly it seems rather farfetched to me.

>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?

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

>		Greg, lee@uhccux.uhcc.hawaii.edu

-- 
	rjc@uk.ac.ed.aipna	AKA	rjc%uk.ac.ed.aipna@nss.cs.ucl.ac.uk

	    "Give me a beer and money sandwich: hold the bread"
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