Why don't you just ask them if it is dark or not?
Randy
On Jan 10, 2005, at 11:47 PM, Horace Heffner wrote:
At 10:29 PM 1/10/5, RC Macaulay wrote:
BlankYa havta love this group!! Stephen Lawrence is correct in his
view.. but.. think again of the question.
The red foot tribe never lies and the green foot tribe never tells
the truth
The question presupposes an attempt by the visitor to determine if the
tribe is red foot or green foot using the knowledge of their
respective
traits of lying or telling the truth by the color of their feet. The
lying
green foot could answer yes and be lying to himself .
It is easy to tell who is whom, even if they will only answer yes or
no,
provided the red foot tribe never lies and the green foot tribe never
tells
the truth, and assuming of course you get an answer.
The question for yes or no answers is: "If I asked the other tribe in
the
region if their feet are red, what would they say"?
The response will always contain a single lie.
If the response is yes, then the true answer is no. The other tribe
has
green feet, thus never tells the truth. The tribe answering has red
feet
and always tells the truth.
If the response is no, then the true answer is yes. The other tribe
has
red feet, thus never tells lies. The tribe answering has green feet
and is
always lying.
Now, if the green foot lies to himself and thereby tells the truth,
this
denies the fundamental premise of the problem that the green foot tribe
never tells the truth. The problem is then merely nonsense. Might as
well
pretend they are all senile. If the green foot tribe in fact never
tells
the truth, and the red foot tribe never lies, and they know a simple
fundamental fact like which tribe is which, then the problem is
meaningful
and it is easy to tell which tribe is present with one yes or no
question.
Regards,
Horace Heffner
