I've heard this before, and am surprised that you haven't yourself, especially being that you are taking a philosophy class. The question that you should ask is "What direction is the other guard going to send me in if I ask him". The liar would lie, and tell you that the truth-teller would send you in the WRONG direction. The truth teller would tell you the truth, which would be, again, the wrong direction. So, it does not matter which guard you ask. All you have to do is go in the opposite direction to get the treasure and avoid certain death.
This is an old riddle, so I am surprised that you haven't heard it before. |