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From: grady@cad.UUCP (Steven Grady)
Newsgroups: net.puzzle
Subject: Re: A logic(?) Puzzle (SPOILER)
Message-ID: <36@cad.UUCP>
Date: Thu, 2-Jan-86 03:57:27 EST
Article-I.D.: cad.36
Posted: Thu Jan  2 03:57:27 1986
Date-Received: Fri, 3-Jan-86 01:40:34 EST
References: <114@drutx.UUCP> <100@nbs-amrf.UUCP> <470@eneevax.UUCP>
Reply-To: grady@cad.UUCP (Steven Grady)
Organization: UC Berkeley, CAD group
Lines: 24

In article <470@eneevax.UUCP> hsu@eneevax.UUCP (Dave Hsu) writes:
>In article <100@nbs-amrf.UUCP> hopp@nbs-amrf.UUCP (Ted Hopp) writes:
>>> You're walking along a road and you come to a fork where the road splits
>>> into two paths, one to the right and one to the left. You don't know 
>>> which way to go, but you must find out. 
>>> You see two people nearby, and you find out that one of them always lies,
>>> and the other always tells the truth. They know which way to go.
>>> You can find out which way to go by asking either one of them ONE certain
>>> question. What is the ONE question?
>>
>>An interesting philosophical point concerns the nature of a lie. ... 
>>...  I don't know how to solve the
>>puzzle for liars of the deceptive sort.
>>
>I believe the deceptive solution is:
>1) ask "Which road will the other tell me to take"
>2) don't take that one.
>
There's no way to get past a "deceptive" liar.  If his intention is to
avoid giving you information, he can simply resolve that he will answer
the same way no matter what question you ask. (For that matter, he could
choose not to respond at all).

	Steven