While exploring the jungle three scientists get caught by a tribe of cannibals. Begging for mercy, they finally are granted one last chance to save their lifes: Each of them is bound to a stake, so that one scientist can see the backs of the other two before him, the one in the middle can only see the back of the one in front, while the latter can’t see anybody. They are now shown five colored feathers, among which there are three white ones and two black ones. They are then blindfolded and each of them is to put one of the feathers into his hair. Finally they are taken off the blindfolds and posed the question to determine the color of their own feathers. If only one of them should be able to guess the correct color, all three of them would be released. Time passes... then the man bound to the foremost stake (who actually can’t see anybody) correctly names the color of his own feather. What thoughts must have lead to his answer?
I'm quite confident that one of his first thoughts was, "I'm in big trouble if I don't get this right." (or something to that effect) Contact me by PM and I'll tell you where to send the prize. Jack (sorry, but my brain has been teased too much today as it is)
If I've pondered this correctly the answer is "white", which is the only color the feather could be and still leave one of the other two scientists unable to answer the question. Details to follow, after I've finished eating my supper!
The scientist in back must not see two black feathers ahead of him, because if he did he could answer "white" with absolute certainty. So he sees either white/white, white/black, or black/white, and therefore must remain silent. The middle scientist realizes that the back scientist can't answer and understands why. Based on the above logic, if the one feather this scientist sees is black then he can answer with absolute certainty "white". However, if he sees a white feather then his own feather could be either white or black, so he must remain silent, also. After waiting patiently, the final scientist realizes why neither of the other scientists has answered the question, and therefore deduces that his own feather must be white.
Ptetty good logic. I was thinking along the lines of shadows. Would black feathers cast darker shadows than white ones? I don't know but this is how I went about it.
