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JackAdams's avatar

Will someone please explain this riddle solution to me?

Asked by JackAdams (6574points) September 8th, 2008

WARNING: If you are prone to migraines, perhaps you should not read the details.

This Q comes from the “Puzzle of The Two Doors” in the movie, LABYRINTH, and admittedly, SOME of these details come from other online chats regarding the puzzle, but here is what I have been able to find:

The heroine comes to a pair of doors, each guarded by a muppet. One of the guards tells her that one door leads to the center of the Labyrinth and the other leads to (dun dun DUN!) certain death! The heroine is told that the guards can point her to the right door, but one guard always tells the truth and the other always lies.

She works out the standard solution to the puzzle (ask one what the other would tell her, then do the opposite) and proceeds.

But, she gets the rules of the riddle from one of the guards, and he might just be the one who always lies!

So what kind of variations would that imply? Obviously, they can’t both be telling the truth (since the statement that one lies would then be a lie). The statement “one always tells the truth and one always lies” is still a lie if both guards lie. So you’ve either got one liar + one honest or two liars.

How could a smart player/character figure out what’s really going on so they can avoid (dun dun DUN!) certain death? Obviously, there needs to be some rules. Let’s say:

The guards are only forced to lie/be truthful when talking about the challenge itself.

What clues would be needed to indicate that this isn’t the “standard” scenario?

Players who just assume that the rules match the expected riddle might get ticked off if they turn out to have gone through the wrong door. Playing against player assumptions shouldn’t edge into playing against the players.

Usually, this type of challenge has a limit on the number of questions you can ask. How many questions would be needed to determine (1)how many liars (1 or 2) and then (2) which door (using the information from 1 to determine how to ask the question)? Or is there some convoluted combination of “what would he say you would say he would say is the right door” that collapses down to a known state regardless of one or two liars?

Or is there just too big a chance that this would go horribly wrong? I doubt consequences would be as high-stakes as “instant death vs. progress” (although “easy route” and “hard route” are definite possibilities).

Don’t hesitate at all to “talk down to me,” when explaining this, because I really have tried to understand it (and all of the purported “solutions,”) and I believe I am going to start drinking again, after 37 years of sobriety.

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22 Answers

scamp's avatar

I never completely understood it myself. You remind me of the babe. What babe? The babe with the power! I watched this several times with my daughter, and I sometimes still do.

syz's avatar

(I’m just impressed that you admit to watching the movie “Labyrinth”.)

JackAdams's avatar

Heck, I watched, BAMBI

scamp's avatar

Me too. Did you cry when his Mother died?

JackAdams's avatar

There’s no HUMAN who can watch that scene, and NOT cry.

scamp's avatar

Aww! Now I feel all warm and fuzzy! I guess it’s time to twitterpate!

JackAdams's avatar

I’d advise against that. It’s still illegal in 27 American states.

scamp's avatar

Ha ha! maybe, but I’m not in one of them right now!

dalepetrie's avatar

syz, what the Hell is wrong with Labyrinth…it’s a kick ass movie. Jim Henson AND David Bowie? I’ve seen it several times, no problem admitting that.

JackAdams's avatar

Interesting…

6 responses thus far, and not one of them a solution to the puzzle…

syz's avatar

Oh, I like fantasy movies (and LOVE Jim Henson), but a lot of folks that I talk to poo poo anything with Muppets, or men in tights (Bowie). My partner looks at me like I’m crazy every time I make her watch fantasy. Her favorite response – “What’s with the bubbles!?!” (A reference to the dreamy, floaty scenes that most of the genre seem to include.)

(There I go, thread-jacking.)

scamp's avatar

@ jackAdams the answer you seek is within your own question. I found the following by clicking on your link:

Here’s where it may get tricky. It has nothing to do with which one is the liar and which one is being truthful. The trick is to get them to give the same kind of answer. And here’s how you do it. You have one truthful guard and one lying guard. If you ask the truthful guard if the other guard (liar) would say the door you’re pointing at would lead to the caste he’ll truthfully tell you what the liar would say because you’re asking the truthful one what the lair would say. So you get the lie as his answer by default. He is truthfully quoting the liar. If you ask the liar if the other guard (truthful) would say if the door you are pointing at leads to the castle the liar would NOT tell you honestly what the other door would say. He would tell you the lie because he is the lair. So you get the lie by default.

Either you’re asking an honest person what a liar would say or you are asking a liar what an honest person would say. As a result you always get the lie as the answer. It’s really very simple. If you ask one door what the other door would say (nevermind which one’s truthful or lying) you will automatically get the lie as the answer by default. It’s very simple.

JackAdams's avatar

No, it is NOT “very simple,” or my Q would not have been asked.

Keep reading the information at the link, and your confidence will be destroyed.

wildflower's avatar

OK, I’ve been thinking about this since last night and here’s the sticking point: What is the opposite of “one always tells the truth, and one always lies” – is it that both tell lies, or is it in fact that one always lies and one always tells the truth in which case, you’re at the same place, one lies, one does not and you can use the same approach as the girl did in the movie….

And now I have to go get the labyrinth on DVD – haven’t seen it in ages!

FlutherMother's avatar

Thank you scamp for your answer – I couldn’t figure out how to explain the answer but you did it beautifully. But that answer is correct when viewing the riddle in the traditional sense – that the rules as given, are true regardless of which guard relays them. What throws us with JackAdams’ question is that the girl received the rules from one of the guards so theoretically, if the rules came from the guard that always lies, did he lie about the rules? And how could she have know for sure if he did lie about the rules? I think the movie actually means that the rules are true regardless of which guard tells them, but JackAdams, I may have to join you in that drink because I can’t figure out for the life of me how to determine if the guard that told her the rules was the liar or the truth-sayer and if that would have any bearing on whether the rules were truthfully given or not. Okay, now I am going to be mulling that for a long time…....

EmpressPixie's avatar

I must be remembering the movie wrong, I thought she didn’t loop her answer enough anyway and got the wrong answer even assuming the rules were correct. She certainly didn’t end up anywhere I’d want to be. Helping hands my dead aunt Fannie!

scamp's avatar

I’m going to watch it again tonight to see if what is within Jack’s link is correct.

JackAdams's avatar

Again, one of the key points to consider is, is the one giving the instructions and conditions to the girl, telling the truth, or lying?

JackAdams's avatar

There’s a 6-part documentary that was made on the making of this movie, but I don’t know if the riddle is addressed on it yet, or not, because I just have not had the time to listen/watch the entire series of videos. If you have more time than I, perhaps you may wish to view them, and then “report back,” regarding which part., if any, addresses the riddle. Here they are:

Part 1: http://www.youtube.com/watch?v=9Qd8IEQSxDQ

Part 2: http://www.youtube.com/watch?v=jQTXmkhDDdg

Part 3: http://www.youtube.com/watch?v=sGhL62B8uz4

Part 4: http://www.youtube.com/watch?v=rWc9rBGcc8w

Part 5: http://www.youtube.com/watch?v=5fpfAyZseR4

Part 6: http://www.youtube.com/watch?v=AN_asEVUcf0

Restless's avatar

This is a great question. When I first saw the movie I’d thought she’d ask them a ‘duh’ question to see which was the liar (like is my hair brown). Of course they both could say something nitpicky like “no your hair is brunt amber” or something more opinion based or really weird & over my intelligence range that would throw the question’s worth to me right out the window. But basically I would have needed three questions, minimal, to solve that riddle hehe.

LexWordsmith's avatar

As long as one of the guards always tells the truth and the other one always lies, ask either one, “If i ask the other guard to point to the door that leads to the center, which one will that guard point to?” Then go through the door not indicated as being the one that would be pointed to.

Loveyajmc's avatar

The point of the riddle is that it cannot be solved. Sarahs caharacter is a know it all and because of this she thinks she has solved this insolvable riddle. If both doors answered yes or no to a door leading to the center then Sarah would know the answer was a for sure yes or know because one door always lies and one always tells the truth. It’s not about the question as to whether the door talking first is lieing about the rules although that is a great question. But about Sarah and her need to grow up and stop thinking it’s all about her and that she knows it all after all this is a movie about her journey through the maze of her childhood fantasies in her mind playing havick.
On another note, idk if you have seen family guys version of this scenario but theY make the person throw a frog into one of the doors. The frog dies because it is the door to certain death so they take the other door. Lol. Sounds like a good solution to me.

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