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>From: petry@corona.math.washington.edu (David Petry)
Subject: Re: Self-Reference and Paradox (was Re: Human intelligence...)
Message-ID: <1992Nov18.051456.24550@u.washington.edu>
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Organization: University of Washington, Mathematics, Seattle
References: <1992Nov14.151559.13227@oracorp.com> <BxtBwx.LvH@unx.sas.com>
Date: Wed, 18 Nov 1992 05:14:56 GMT
Lines: 28

In article <BxtBwx.LvH@unx.sas.com> sasghm@theseus.unx.sas.com (Gary Merrill) writes:
>
>In article <1992Nov14.151559.13227@oracorp.com>, daryl@oracorp.com (Daryl McCullough) writes:
>
>|> 
>|>     This sentence is false.
>|> 
>|> refers to an unrestricted notion of falsity, and is therefore
>|> meaningless. We can replace "false" by a restricted notion of falsity
>
>This sort of thing has been tried before.  One problem is that the displayed
>sentence is *not* meaningless in any normal sense of this term.  We
>know perfectly well what it means -- and that's the problem.

Well, we think we know perfectly well what it (the paradoxical sentence)
means, but we humans use non-monotonic logic.  That is, we are willing to 
reject our previous conclusions in light of new knowledge.

For example,  if you found out that I had just written down the sentence
"2+2 = 5" and was pointing to it while I exclaimed "This sentence is false",
you would quickly change your belief about the meaning of that exclamation.

I've always felt that that observation is crucial to the understanding of
the so-called paradoxes.


David Petry



