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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