• HexesofVexes@lemmy.world
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    1 day ago

    So the traditional answer here is to ask them to point at the door the other guard will say is safe.

    However, I’m curious, does anyone know of any other valid solutions?

    • EntirelyUnlovable@lemmy.world
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      1 day ago

      “Is the guard that tells the truth standing in front of the safe door?” If they say yes, you go through their door, if they say no then you go to the other one

        • entropicdrift@lemmy.sdf.org
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          1 day ago

          Right, in which case the door they’re in front of is the safe door because they lied and said “Yes” when asked if the truth teller is in front of the safe door. And if they tell the truth and say yes, they’re still the person in front of the safe door. By asking it that way they make it so it doesn’t matter if they’re the liar or not. “Yes” means that person’s door is safe and “No” means you want the other door, no matter who you ask.

          • BigAssFan@lemmy.world
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            12 hours ago

            I was thinking: he could lie about the guard but not about the safe door, so he would still be lying. But that’s technically a half-truth, which this particular guard isn’t capable of. So you’re absolutely right, thank you.

    • Cargon@lemmy.ml
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      1 day ago

      Could probably do something clever with XOR.

      Is exactly one of the following statements true? You are the liar. Your door is the safe door.

      • zarkony@lemmy.zip
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        1 day ago

        They will both point to the bad door.

        If asking the thruthful guard, he will point to the door the liar says is safe, which would be the bad door. If asking the liar, he would consider what the thruthful guard says is safe, then reverse that answer, still ending up on the bad door.

        They cancel out, so whichever guard you ask doesn’t matter.

      • MajorasTerribleFate@lemmy.zip
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        1 day ago

        The liar, knowing the truth-teller will point to the good door, points to the bad door.

        The truth-teller, knowing the liar would point to the bad door, points to the bad door.

        Either way, you take the one your guard doesn’t point to.

          • Buddahriffic@lemmy.world
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            9 hours ago

            The answer is stable because the liar will always say the bad door is safe and the truth teller will always say the safe door is safe, therefore the liar will always say that the truth teller will direct you to the danger door and the truth teller will tell you the same.

            I tried to add some self-reference to the question to make a paradoxical answer but can’t see a wording that even causes something like “this statement is false”, at least not one about which door to pick.

            Only ways I can think of start with the paradox right in the question. Like “If the other guard said, ‘this statement is false’, would you believe him?”

            Sucks someone downvoted just for asking questions to better understand this less than straightforward thing. I’ve always believed that if you think something is wrong, you should challenge it, because even if you are wrong, the resulting discussion can help you understand why your previous perspective was flawed, which might then cascade to other things you didn’t realize you were also mistaken about.

          • MajorasTerribleFate@lemmy.zip
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            14 hours ago

            The question we ask if “What would the other guard say if I asked him which door is the good one?”

            Liar says Bad Door

            Truther says Bad Door

            Now, for their answers to update, they would have to ne answering the question, “Which door would the other guard say if I asked him ‘Which guard would the other guard say is the good door?’”

            We want a guard to answer “What would the other guard say is the good door?” Regardless of how they answer our “outer” question, the answer to the “inner” question (“which is the good door?”) doesn’t change.

            Liar doesn’t care that Truther would say that “Liar would say the right door is the good one,” Liar is being asked how Truther would answer “Which door is the good one”.

            I know I basically just said the same thing three times. My brain isn’t working to break this out the elegant way I can’t quite assemble. But hopefully some part of all this helps. The crux is that the question that they are imagining the other guard’s answer to is not the same question they themselves are being asked.