Banging My Head Against The Wall With This Riddle

[Restrikted]

My Philosophy professor emailed our class this question to see if we could figure it out, and we'll get bonus points if we answer it correct. But I've been going crazy trying to figure it, and I honestly don't think it's possible. Without further ado:

Imagine you are going down a river in search of a treasure that you know is guarded by two guardsmen. You know one of these guardsmen always tells lies (whatever he says is false), while the other always tells the truth (whatever he says is true). They are standing by a fork in the river. If you follow one of these forks, the treasure is yours. If you follow the other, you will meet with certain death. You are allowed to ask only one of the guards only one question, and you cannot be sure whether the guard you are asking is the truth-teller or the liar.

What one question can you ask that will guarantee that you will get the treasure rather than meeting with certain death?

Does anyone have a clue? I don't know how it's possible to figure out who is the liar while simultaneously figuring out which way to go without asking a compound question, which isn't allowed.

[WanderingOak]

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.

[tomstine]

Just to reiterate the prior answer, ask which way will the other guard say. Great riddle. I love it.

[Angela]

It's funny, this same riddle has come up a couple of times in these forums!

There is the logical answer, which will now reward you with the treasure your professor promised: bonus points.

But what if the guard tells you there is no treasure, and there is no death?

[Niki]

Reminds me of: There is no spoon :-)

[Angela]

Originally Posted by Niki

Reminds me of: There is no spoon :-)

Yes! I am only now just beginning to absorb my truth of that, and my entire world is turning upside down.

[Restrikted]

Ahh I finally get it, by going through both people there is no need to know which is the liar. Thanks guys!

[WanderingOak]

Originally Posted by Restrikted

Ahh I finally get it, by going through both people there is no need to know which is the liar. Thanks guys!

With the question that we gave you ("What direction is the other guard going to send me in"), it doesn't matter which guard you ask. Both guards are going to point you in the wrong direction, so all you have to do is ask one.