Date: Jul 6, 2013 5:24 AM
Author: INFINITY POWER
Subject: Re: Real-world example of the liar paradox

On Saturday, July 6, 2013 5:08:41 PM UTC+10, Paul wrote:
> Nick Davies's book, Flat Earth News, says "it is a very safe bet that
> there are mistakes in this book." Later, I met the author and reminded him
> of this quote, and asked him what the mistakes were. He replied that the
> only error he knew of was extremely minor. (He described the error, but I
> forget the details.) If we tweak this account just a little bit and deem
> the book to be free of mistakes, then we get the liar paradox -- the only
> mistake in the book is the assertion that there are mistakes in the book.
>
>
>
> Paul Epstein




I made a quick program for this ...

herc said [liar bethy ]

bethy said
[liar herc] &
[herc said [liar bethy]]
->
truthful bethy
->
liar herc



> if you always lie, and you say that I am a liar, then I must be telling
> the truth, which means that you do always lie (?).





but I think my automated Proof got her!

http://phpprolog.com/TRUTHER-LIAR.png



5 assert herc [ liar bethy ]


7 true X :-
assert P X
truther P


8 false X :-
assert P X
liar P


10 truther X :-
assert P [ liar X ]
liar P


11 liar X :-
assert P [ liar X ]
truther P



liar herc ?

HEAD 1
liar X
TAIL 1
assert P liar X
assert P liar [ herc ]
FALSE 1
FAIL


Herc
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