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From: morrison@cs.ubc.ca (Rick Morrison)
Newsgroups: comp.databases
Subject: Re: errors and 4 valued logic
Keywords: logic, truth values
Message-ID: <10356@ubc-cs.UUCP>
Date: 6 Nov 90 18:49:10 GMT
References: <694@creatures.cs.vt.edu>
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Organization: University of British Columbia, Vancouver, B.C., Canada
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In article <694@creatures.cs.vt.edu> holliday@csgrad.cs.vt.edu (Glenn Holliday) writes:
>Chuck Phillips  writes:
>>Clairification: A statement requiring the existance of the non-existant to
>>be true, is simply false, not an error.  However, a domain violation _is_
>>an error.  (e.g. "I am green years old.")
>

The bald king of France has interested philosphers of language for a very 
long time. For those who are interested, there is a very nice paper by
Russell that discusses this and related problems:

@incollection{russell4,
   author =        {Bertrand Russell},
   title =         {Descriptions},
   booktitle =     {Semantics and the Philosophy of Language},
   publisher =     {University of Illinois Press},
   address =       {Urbana},
   year =          {1952},
   editor =        {Leonard Linsky},
   chapter =       {6},
   pages =         {95-108},
   note =          {Reprinted from Chap. XVI, {\it Introduction to
                    Mathematical Philosophy}, 2nd ed. London:
                    Allen and Unwin, 1920.},
   keywords =      {philosophy language semantics indefinite descriptions
                    definite descriptions}
}

As I recall, Russell took the view that 
       "the present king of France is {bald, hirsute}"
be understood as 
       (Ex) (PKOF(x) & Bald(x)), 
respectively
       (Ex) (PKOF(x) & Hirsute(x)), 
both of which are false.

The collection includes papers by Quine and others on the same topic.
Great reading.
----------------------------------
Rick Morrison		 | {alberta,uw-beaver,uunet}!ubc-cs!morrison
Dept. of Computer Science| morrison@cs.ubc.ca
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