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        riddles >> general problem-solving / chatting / whatever >> Another one-and-a-half
        
(Message started by: udippel on Feb 1^st, 2003, 1:34am)

Title: Another one-and-a-half
Post by udippel on Feb 1^st, 2003, 1:34am

This is probably some place in here, but I'm too lazy to read *everything*.

Actually, I have two:

very easy:
Any member of a tribe of fair-haired sees everything as it is and always tells the truth. Any member of a tribe of brown-haired people never sees anything as it is and never tells the truth.
If you show a fair-haired one a green field and ask if it is green, what will he answer? What will the answer of a brown-haired species be?

with the answers of these in mind:
Do we have a chance to find out who's who by asking a question to either of them?

Sorry if this is a repetition. At a certain moment the amount of riddles overwhelms the basic tree-like structure in here !

Title: Re: Another one-and-a-half
Post by prince on Feb 11^th, 2003, 10:50am

I've never seen this puzzle worded quite this way before, and it seems to leave some uncertainty.
First, I'll assume we can only ask yes or no questions--if I ask "what color is this (green) field, I could get "yellow" as an answer, and then know it's a brown-haired person.
Secondly, does brown-hair only affect sight? The way the puzzle is worded, I could ask "Do you hear this question?" To which the brown-haired person would have to answer "no".
If we reword it, so that the brown-haired person never perceives anything as it is, I don't think we can even ask a question.

Title: Re: Another one-and-a-half
Post by wowbagger on Feb 12^th, 2003, 1:24am

on 02/11/03 at 10:50:02, prince wrote:

if I ask "what color is this (green) field, I could get "yellow" as an answer, and then
know it's a brown-haired person.

The problem arises if you get the answer "green", because it could be given by a member of either tribe.

Quote:

Secondly, does brown-hair only affect sight? The way the puzzle is worded, I could ask "Do you hear this question?" To which the brown-haired person would have to answer "no".

Unless the brown-haired person is deaf! ;)

Quote:

If we reword it, so that the brown-haired person never perceives anything as it is, I don't think we can even ask a question.

This is an important point. I guess the "see" in the problem statement was meant in a broader sense, referring to any kind of perception (excluding ESP, maybe).

In case the brown-haired people understand questions properly, I suggest letting the person look into a mirror and asking them: "Do you have brown hair?"

Title: Re: Another one-and-a-half
Post by wowbagger on Feb 12^th, 2003, 1:56am

on 02/01/03 at 01:34:24, udippel wrote:

This is probably some place in here, but I'm too lazy to read *everything*.

Let me refer you to the following riddles (at least in parts well-known) and threads, which are related to the one at hand:
Fork in the Road I (http://www.ocf.berkeley.edu/~wwu/riddles/hard.shtml#forkInTheRoad1), thread (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=display;num=1033971551)
Fork in the Road II (http://www.ocf.berkeley.edu/~wwu/riddles/hard.shtml#forkInTheRoad2),
mixed thread (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=display;num=1027807082) for FitR I & II,
Fork in the Road III (http://www.ocf.berkeley.edu/~wwu/riddles/hard.shtml#forkInTheRoad3), thread (http://www.ocf.berkeley.edu/~wwu/cgi-bin/yabb/YaBB.cgi?board=riddles_hard;action=display;num=1037291117)

Quote:

Sorry if this is a repetition. At a certain moment the amount of riddles overwhelms the basic tree-like structure in here !

I know by experience that the plethora of riddles and threads can be intimidating at first. Take your time to dig into the older posts as well, it's worthwhile!

Title: Re: Another one-and-a-half
Post by udippel on Feb 12^th, 2003, 9:12am

Thanks for the hint(s) !
Actually, the fair-haired in the mirror was the one I was missing. The whole thing is the not-not-A = A thing, as is obvious.
I was actually clueless when asked if this is generally true and could only stumble not-too-intelligent things about classical logic and its limits.

With respect to the other thing (overwhelmed), I've tried in vain to come up with better. Not all of us are paid by the government to keep our brains in perfect state, but have to make a living outside of the riddles. And then hundreds of riddles in different categories and thousands of threads are beyond reach.

Is there any literature on 'categorising riddles' ? Maybe someone can still get a PhD for something like this ?!

Title: Re: Another one-and-a-half
Post by aero_guy on Feb 12^th, 2003, 7:25pm

Somebody did. I believe they reference him in this article.

http://www.nyx.net/~drwalker/ny_riddler.html

Dr of cryptology I think they called it.