The bartender asks “Do all three of you want a beer?”

The first logician says “I don’t know”.

The second logician says “I don’t know.”

The third logician says “Yes.”

  • Nyarlathotep@lemmy.world
    link
    fedilink
    English
    arrow-up
    18
    ·
    1 year ago

    I find It pretty funny told my high school teacher this joke once and he looked at me really weird hahaha.

  • logicbomb@lemmy.world
    link
    fedilink
    English
    arrow-up
    26
    arrow-down
    11
    ·
    1 year ago

    For this joke to logically work, logicians must be weird people who always know whether they want a beer or not. Because if it happened that the first guy just hadn’t made his mind up yet, then the third guy’s conclusion could be wrong.

    • joku415@lemmy.world
      link
      fedilink
      English
      arrow-up
      50
      arrow-down
      2
      ·
      1 year ago

      They all had made up their mind. You don’t need to know the others decision to answer No to the question, but you do to say yes. If the first didn’t want a beer they could definitively answer no. They did, but didn’t know the others decisions so couldn’t say yes. Same with the 2nd. The third could say yes because he knew the other two didn’t say no, so whatever they wanted was the answer

      • Ignotum@lemmy.world
        link
        fedilink
        English
        arrow-up
        22
        arrow-down
        3
        ·
        1 year ago

        OCs point was that if the first person hadn’t made up their mind yet, that would also cause them to say “i don’t know”, but the two following logicians seem to assume that the first person said “i don’t know” because they wanted it but didn’t know if the other two did

        It’s a false dichotomy and faulty logic if you look too closely

        But it’s a pretty funny joke

        • MxM111@kbin.social
          link
          fedilink
          arrow-up
          22
          arrow-down
          1
          ·
          edit-2
          1 year ago

          If he has not made a mind, he does not want beer. He might want beer few moments later, but at the moment of answering the question, he does not. That’s what my logic tells me.

          • Ignotum@lemmy.world
            link
            fedilink
            English
            arrow-up
            6
            ·
            1 year ago

            Hmm, that’s true, if the question is if all three in this moment wants a beer, then not knowing if you want it means that you don’t currently want it in the strictest sense 🤔

          • logicbomb@lemmy.world
            link
            fedilink
            English
            arrow-up
            3
            ·
            1 year ago

            This is a good point, but I’ll move the goalposts very slightly and suggest that human brains are capable of wanting something without knowing that they want something. For example, if you say you don’t know whether you want a beer, and then the person next to you orders a beer, then at that moment, you might realize that you really did want a beer before.

            • thepianistfroggollum@lemmynsfw.com
              link
              fedilink
              English
              arrow-up
              4
              ·
              1 year ago

              It’s been shown that your brain makes it’s decision several seconds before your consciousness is aware of it.

              So, it just takes a second for the Ego to catch up with the Id

              • MxM111@kbin.social
                link
                fedilink
                arrow-up
                1
                ·
                1 year ago

                More like 100-300 ms, but yes. However, this is much shorter time than to say “I do not know”

                • thepianistfroggollum@lemmynsfw.com
                  link
                  fedilink
                  English
                  arrow-up
                  2
                  ·
                  1 year ago

                  I think the areas of your brain that would be responsible for carrying out the decision start activating before you’re consciously aware of making the decision.

                  It’s been a hot minute since I read the article on it, so I’m not 100% sure on the explanation.

        • bushvin@lemmy.world
          link
          fedilink
          English
          arrow-up
          4
          ·
          1 year ago

          Logicians is the keyword here… There are only 2 possible answers: yes (true) or no (false)

          In logic there is no other option

    • alvvayson@lemmy.world
      link
      fedilink
      English
      arrow-up
      20
      arrow-down
      3
      ·
      1 year ago

      If any logician hadn’t made up his mind, then the answer to “do all of you want a beer” would be False, i. e. No.

      The idea that a Yes/No question can have any other state is not possible for these cartoonish logicians.

      (Of course, “logicians” do not exist. The closest thing in real life are mathematicians and computer scientists who are trained in logic, and these people known that the real world works differently than the simple logic presented in this joke, so your point is valid at some level, but it doesn’t invalidate the joke)

      • Kogasa@programming.dev
        link
        fedilink
        English
        arrow-up
        3
        ·
        1 year ago

        Logicians certainly do exist. Some of them might be called mathematicians or philosophers but that doesn’t mean they’re not logicians.

        • alvvayson@lemmy.world
          link
          fedilink
          English
          arrow-up
          2
          arrow-down
          2
          ·
          1 year ago

          So these logicians of yours, do they all want a beer?

          Yes, humans who study logic and specialize in it exist, and you can call them logicians, but the point is that they have a much broader understanding of math, philosophy and different modes of logic than the “logicians” used in these jokes, who are caricatures that paradoxically are called logicians, but at the same time only follow a very basic mode of logic that is taught in undergraduate classes.

          Such logicians do not exist and cannot exist.

    • Bartledan@lemmy.world
      link
      fedilink
      English
      arrow-up
      11
      arrow-down
      1
      ·
      1 year ago

      First guy knows he wants a beer, but doesn’t know if the others do, so says he doesn’t know if all three do. However, if he had not wanted a beer, he would have known that not all three wanted one, and therefore would have said no. Which means the second guy then knows that the first guy wants a beer, but does not know if the third does. So he says he doesn’t know. That gives the third guy, who also wants a beer, with enough information to say that all three want a beer

    • NeoNachtwaechter@lemmy.world
      link
      fedilink
      English
      arrow-up
      7
      ·
      1 year ago

      logicians must be weird people who always know whether they want a beer or not.

      Don’t you think you should have made up your mind at that point when the barkeeper asks you? :-)

      At least when it says logicians, I expect them to know. Weird people are the others, those who don’t know.

    • nudny ekscentryk@szmer.info
      link
      fedilink
      English
      arrow-up
      1
      arrow-down
      4
      ·
      1 year ago

      none of them would go to a bar if they didn’t mean to consume some drink – therefore we can assume all of them knew whether they wanted a beer or not.