Can you solve the three gods riddle? – Alex Gendler

Can you solve the three gods riddle? – Alex Gendler

Created by logician Raymond Smullyan and popularized by his colleague
George Boolos, this riddle has been called the hardest
logic puzzle ever. You and your team have crash-landed
on an ancient planet. The only way off is to appease
its three alien overlords, Tee, Eff, and Arr, by giving them the correct artifacts. Unfortunately, you don’t
know who is who. From an inscription, you learn that you
may ask three yes or no questions, each addressed to any one lord. Tee’s answers are always true, Eff’s are always false, and Arr’s answer is random each time. But there’s a problem. You’ve deciphered the language enough
to ask any question, but you don’t know which of the two
words ‘ozo’ and ‘ulu’ means yes and which means no. How can you still figure out
which alien is which? Pause here if you want
to figure it out for yourself! Answer in: 3 2 1 At first, this puzzle seems not just hard,
but downright impossible. What good is asking a question if you can neither understand the answer
nor know if it’s true? But it can be done. The key is to carefully formulate
our questions so that any answer
yields useful information. First of all, we can get around
to not knowing what ‘ozo’ and ‘ulu’ mean by including the words themselves
in the questions, and secondly, if we load each question
with a hypothetical condition, whether an alien is lying or not
won’t actually matter. To see how that could work, imagine our question
is whether two plus two is four. Instead of posing it directly, we say, “If I asked you whether
two plus two is four, would you answer ‘ozo’?” If ‘ozo’ means yes
and the overlord is Tee, it truthfully replies, “ozo.” But what if we ask Eff? Well, it would answer “ulu,”
or no to the embedded question, so it lies and replies ‘ozo’ instead. And if ‘ozo’ actually means no, then the answer to
our embedded question is ‘ulu,’ and both Tee and Eff still reply ‘ozo,’ each for their own reasons. If you’re confused about why this works, the reason involves logical structure. A double positive and a double negative
both result in a positive. Now, we can be sure that asking
either Tee or Eff a question put this way will yield ‘ozo’
if the hypothetical question is true and ‘ulu’ if it’s false regardless of what
each word actually means. Unfortunately,
this doesn’t help us with Arr. But don’t worry, we can use our first
question to identify one alien lord that definitely isn’t Arr. Then we can use the second to find out
whether its Tee or Eff. And once we know that, we can ask it to identify
one of the others. So let’s begin. Ask the alien in the middle, “If I asked you whether the overlord on
my left is Arr, would you answer ‘ozo’?” If the reply is ‘ozo,’
there are two possibilities. You could already be talking to Arr,
in which case the answer is meaningless. But otherwise, you’re talking to either
Tee or Eff, and as we know, getting ‘ozo’ from either one means
your hypothetical question was correct, and the left overlord is indeed Arr. Either way, you can be sure the alien
on the right is not Arr. Similarly, if the answer is ‘ulu,’ then you know the alien
on the left can’t be Arr. Now go to the overlord you’ve determined
isn’t Arr and ask, “If I asked ‘are you Eff?’
would you answer ‘ozo’?” Since you don’t have to worry about
the random possibility, either answer will
establish its identity. Now that you know whether its
answers are true or false, ask the same alien whether the center
overlord is Arr. The process of elimination will identify
the remaining one. The satisfied overlords help you
repair your ship and you prepare for takeoff. Allowed one final question, you ask
Tee if it’s a long way to Earth, and he answers “ozo.” Too bad you still don’t know
what that means.

100 thoughts on “Can you solve the three gods riddle? – Alex Gendler

  1. Both (as in eff and Teff) have their own reasons for saying let’s say “no” which prove that the hypothetical question is true. Just don’t combine them together if that makes sense. Or just pretend ur talking to only one of them and the other doesn’t exist. So let’s pretend we’re only asking the one who says truth , “If I were to ask you whether 2+2=4, would you say no?” The one who says truth would say, “No, I would not say no as I would say yes to that question (2+2=4)” Then that basically means by saying no, the one that says truth is essentially saying that 2+2 is 4 (REMEMBER pretend that there’s only the one who says truth in the room). And if you were to ask that question to the one that lies, he would think: as I am the liar I would say that 2+2 doesn’t equal to 4 as that is a true statement, but because I would say no to 2+2=4, when given the question on whether I would say no to that question, the true statement is yes, so I have to lie and say no. (REMEMBER just pretend that in this moment, there’s only the one who says false stuff in the room, because if there is only one who says false stuff in front of you, by replying no, and following his train of thought, we know that he’s saying 2+2 does equal to 4. ) Therefore it doesn’t actually matter who we ask cause both of them have their own reasons and train of thought that prove that by saying no, 2+2 is indeed 4.

  2. But what if the alien in the middle is Arr? This solution seems to work only if you assume that the alien in the middle is either Tee or Eff. It's a 2/3 shot, but not a certainty.

  3. This video only addresses half the riddle. You still don't know what artifact to give to what overlord. Maybe the artifacts are labeled and that wasn't mentioned is all I can think.

  4. “If I asked you if you are Eff, would you answer Ozo?”
    Monster says Ozo, is Eff
    Monster says Ulu, Is Tee
    “Is it a long way back to Earth?” Tee says Ozo
    “Too bad you still don’t know what Ozo means”

    Bruh, you pretty much revealed what Ozo meant

  5. Why not ask a math question like is 1+1 2 if tee who always tells the truth will say yes in alien language then you will know which one is yes in alien language and know whick is know in alien language see my idea is to go up to tee and ask him or her or it whats 1+1 then when he or her or it will tell you ulu or ozo either way then you will know what ulu means and ozo means

  6. Why don’t you just ask if ozo means yes. If they reply ozo, then ozo means yes. If they reply ulu, then ozo means no. Boom you know what they mean now 💥

    Jk that won’t work

  7. How to figure out what ozo and ulu means ask tee "is ozo yes?" Is he says ozo then ozo means yes in he says no it means no

  8. Wait, I translated every word except yes and no?! How did I not translate that?! How did I even read the inscription!?

  9. anyone remembered joe Friends " first u lied and then u lied about lying and then u lied about lying about lying " Scene at 2:10

  10. Wow! I was misled by 1st condition! Each question to any one Lord! What does it mean? Can I question the same Lord twice?is it? Then I just let my time wasted by thinking over it.

  11. I think that complex anwer is the same to my simple one
    1, do you talk the truth? Both T and F say yes (ozo or lulu)
    2, do you tell the lies? Both T and say no ( lulu or ozo )
    1 and 2 -> R
    3, is this R? T say yes, F say no

  12. Why do you know the language but not know the difference between yes and no… like maybe you should’ve learned it more

  13. If you asked tee if the middle his rrr then you would know the meaning of ulu and ozo cause his answer would mean yes or no based on whether the middle is or is not in correlation to it

  14. If we established who Tee is and then we ask Tee if he would respond OZO if we asked if the center alien is Arr and Tee says OZO then we know the middle alien is Arr. You explain this in the video. If that’s the case, doesn’t OZO mean yes?

  15. But even with the solution, isn’t there still not a 100% chance of it working? 1/3 of the time you’ll ask the first question to the wrong lord, and half of that 1/3 the answer will mislead you. So it’s the best solution yeah but not guaranteed

  16. Just ask which ones are which and ask if the gift that you are guessing is there’s or not and wait this wouldn’t work at all I am sorry for being a dummy

  17. Could you just say anything addressed to a lord and know then? For example:
    "Tee, do you have a father?"
    Whichever one answers is Tee.

  18. Can’t you use a fact question? Like , “oh ,do you have 4 legs?” And randomize for each overlord. That would work too? Would it not?

  19. Ask 1 alien 2 questions and if one says ulu the 2 times then ask the opposite one then if the other alien says the other answer then you should know witch is witch elemineting the other one BOOM
    (Edit) or just ask "raise your hand if your so and so

  20. I saw this two years ago and gave up on trying to understand it. Today I looked at the text on paper and finally got it Jesus Christ I'm dropping out of college.

  21. What if we asked each one of them, one at a time, "Are you Eff?", we'd either get 3 No's, or 2 No's and 1 Yes from Arr, because Tee would truthfully say No, Eff would lie and say No. Thus you'd know what Ozo and Ulu each mean. Then ask each of them if 2+2=4, you'd either get 2 Yes's and a No, or 2 No's and a Yes, in which case, the only person saying No would be Eff, or the only person saying Yes would be Tee, either way you now know what Ozo and Ulu are, and who Tee or Eff is, and can use them to figure out the rest.

    1. Is there a McDonald's anywhere here? (cuz eating a Big Mac helps me think better)
    2. Would you like back ur artifact?? Since he says ozo or err and I don't understand him I'll just take it for myself
    3. Also is there something called as Dr.peppers in ur world???

  23. I feel that this is what people that took a foreign language in school are reminded of when they speak to someone from that country

  24. 3:33에 '티'나 '오조'에게 질문을 한 것이 아니라 '티'나
    '에프'에게 질문을 한 거에요

  25. Alien Lords: get me my artifacts!
    You: No, I don't think I will.
    Alien Lords: I am inevitable
    You: I can do this all day

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