Can you solve the three gods riddle? - Alex Gendler

TEDTED-EdTED EdTED EducationAlex GendlerArtrake Studioriddleproblem solvingcritical thinkingRaymond SmullyanGeorge Boolos

View full lesson: http://ed.ted.com/lessons/can-you-solve-the-three-gods-riddle-alex-gendler

You and your team have crash-landed on an ancient planet. Can you appease the three alien overlords who rule it and get your team safely home? Created by logician Raymond Smullyan, and popularized by his colleague George Boolos, this riddle has been called the hardest logic puzzle ever. Alex Gendler shows how to solve it.

Lesson by Alex Gendler, animation by Artrake Studio.

kellyloganme
There is a paradox inherent in this puzzle. If you ask Eff or Tee what Arr will say, they can't answer because Arr's answers are random. The solution avoids this issue, but I used it instead.

1st question - ask first, "would second say its name is Arr?" Does the first answer?
Yes - Then either the first is Arr and the answer could be true or false, or the first and second are Tee and Eff (but which is which is still unknown) and the answer means Yes.
2nd Question - Ask second, "would third say it's name is Arr?" Answered?
Yes - First is Arr, answer given means Yes
3rd Question - Ask second, "are you Arr?"
No answer - second is Tee, third is Eff, first is Arr
Yes answer - second is Eff, third is Tee, first is Arr

No - Third is Arr, answer to first question means Yes
3rd Question - Ask first, "are you Arr?"
No answer - first is Tee, second is Eff, third is Arr
Yes answer - first is Eff, second is Tee, third is Arr

No - The second is Arr.
2nd Question - Ask first, "would third say its name is Arr?" Answer means Yes.
3rd Question - Ask first, "Are you Arr?"
No answer - First is Tee, third is Eff.
Yes answer - First is Eff, third is Tee.
I'm Bren-DONE with phantastic memes
Is that kid Dora?
powerball 123
3,666,665 views. seems legit
Nth Bar-Fields
A friend posted this in our group Elysian Trust. He asked if we could come up with alternative answers. I came up with the following.

Steps 1 and 2. Ask two of them a question that requires them to know something impossible. "Does X = Y+2?" The question can not be answered without more information.
Tee won't be able to answer and neither will Eff. But Arr can, and it doesn't matter if Arr says 'ulu' or 'ozo.'
If both are silent, then you know the one you didn't ask was Arr.

Step 3. Then you ask one of the constants a double negative or double positive question about itself. "If I asked you is Arr Arr, would you say 'ulu?"

If I am asking Tee, and ulu means 'yes,' then the answer would be 'ulu.'
If am asking Tee, and ulu means 'no,' then the answer is 'ulu"
If am asking Eff, and 'ulu' means 'yes', then the answer is 'ozo."
If I am asking Eff, and 'ulu' means 'no,' then the answer is 'ozo.'

So if the answer is 'ozo' I am dealing with Eff, already isolated Arr, and can deduce Tee via process of elimination.
If the answer is 'ulu,' I am dealing with Tee, already isolated Arr, and can figure out Eff via process of elimination.

However he came up with a much simpler solution than this. Can you figure it out or do better?
Mapping Power
for my fist question, I would say "If I asked if Arr always lies, would you say ozo?" Because Tee and Eff wouldn't be able to answer, the alien that does answer is Arr
The Omega Mudkip
Learning the words yes and no are usually the first things you learn when you learn a language
Kleo3392
But we only got three questions, and they're all used on finding out who's who. What about the other one we need to find out which word means yes?
Sᵖˡᵘʳᵍˡᵉ
how about, "is your name Tee ?"
Sener
what
Genevieve Globke
Ted-ED:can you solve this riddle?
Me: YTF R U ASKIN ME!? ASK ALBERT EINSTEIN INSTEAD MOTHER F**K*R!!!!
Fharish Ahmed
Confusing as anything!
Melt down
At 2:11 eff lies and answers ulu not ozo...cuz ozo is yes here
GlittergirlMSP50
Hahah I got it yay😊
jerwen9
there is another possibility: asking if you asked arr a question would he say ...
if he answers its arr, if not, it is tee or the other alien
some tae and suga with a kookie by the side
i still don't get it
agh
Kevin Arpani
the last question to Tee would be,
is 2+2=4? if he answer ozo then ozo mean yes

and even if its take long journey to earth at least i can die in peace know the ozo and ulu mean
ruchi charan
me to arr: are you arr?
arr to me:Ilike turtles one solved 2 to go
Shannen Canton
I would just put the artifacts in front of them and let them pick. They probably don't understand what I'm saying anyway.
V
I don't get why they are making it so complicated:

I walk in assuming ozo means "yes" and ulu means "no"

1. First question to Overlord#1 "If I asked you if my shirt is color grey, and it is, would your answer be ozo?"

Overlord#1 replies:
If he says ozo assuming ozo means yes then he is correctly saying yes, my shirt IS color grey and he is telling the truth. If ozo actually meant "no", and he is replying with ozo, then it means he is telling the truth once again, cause it means I just asked him the question "would your answer be no?", and with him replying "no", he is admitting he would not say no cause the shirt really is grey, and instead would rather say yes.
- So if he replies with the same word then it means it is truthful and he is either Tee or Arr cause Arr just says random stuff so 50-50 - It is Eff 50-50 if ozo means yes, will explain later)

If he replied with ulu to "would your answer be ozo?" when my shirt is color grey and assuming ozo means yes once again, then he is practically saying I would lie, my answer would not be ozo cause I'm trying to lie to you and I would say "no, my answer would not be "yes" to your question"........you realized what just happened....we just met Arr, cause Eff the liar would never admit that he is lying.
- If this scenario takes place then we 100% met Arr and now we know who Arr is and can single him out.

Think about it, "would your answer be yes(ozo)? "Eff would not truthfully answer by saying ulu(no), he would not admit that the shirt is color grey, but at the same time he would not admit he would answer untruthfully by saying no, so instead he would lie by saying yes, even though the correct answer to the question is actually yes, my shirt is grey, he is saying yes for a different reason, the lie is: "yes(ozo), my answer would be yes to your question"...let's write in the form of the conversation, Me: ""If I asked you if my shirt is color grey, and it is, would your answer be yes(ozo)?" Eff the liar would say: "yes" <-- that is a lie, in reality he is thinking "no" but he can't say it, cause if he said "no" he'd be telling the truth, he'd be saying what he really thinks, and the rules state that he will always lie. So only Arr could make such a random nonsensical answer as actually replying no to such a question....again...ASSUMING ozo means yes.

If we assume ozo means no, and his answer is ulu(yes), then it means the Overlord is Arr with his random answering for no particular reason. Tee would not say yes in that scenario cause that would mean he is lying, the shirt is grey, if I asked him if his answer would be no as ozo, the word ulu would never come out of his mouth, so the person we'd be talking to could never be Tee. And Eff cannot be it either cause he would never admit to tell the truth that "yes" my answer would be no, he would never say ulu(yes) either cause that would be telling the truth of the lie he wishes to say "would your answer be no?" Yes of course his answer would be no, but saying that in itself would be telling the truth, so ulu as yes would never come out of Eff's mouth if ozo means no.

-So once again we find a sure way of finding out who Arr is.

2. Second question to Overlord#2 "If I asked you if Overlord#1 told the truth when answering my previous question, would your answer be ozo?"

If we get 2 out of the 4 scenarios that expose Arr then we single out Arr and we don't need to worry about him anymore or ask this specific question to find out who is the first Overlord we questioned...if Arr didn't come out, or it is not certain, then we need to use probability and ask them same question again to this second Overlord and hopefully we root out Arr this time around.

But assuming we already got Arr, we ask this second question to Overlord#2, assuming ozo means yes.

If Overlord#1 answered ozo when we assumed ozo meant............sigh fuck this shit you guys continue from where I left off.
xXxMartin96xXx
But if you ask Eff if he would say Ozo to 2+2 = 4 then he would say Ulu, not Ozo?
chase erickson
This one made me lose it. Like if you agree 😂
Hannah Creasor
Am I stupid?

I'm thinking that you could ask the person who always answer true if Ozo means yes. Than do you really need the other two questions? I mean, if you've deciphered their language you should know enough of the culture to know the artifacts? I feel 99% sure this isn't it though. Should I just take the 50% chance I know which one is yes or no? WAIT...

IF one of the words is yes, and the one always speaks truth, than wouldn't any question be yes? No, it wouldn't. Wait am I overcomplicating... I'll reply with what I find in the video.
harshada samant
A double positive always forms a positive. Yeah, right!
Igneel
the answer is flawed, eff is literally lying twice, like he first says to himself 2+2=4 is no and says yes, that basiclaly means no.matter what u ask itll say the truth
Igneel
this doesnt make sense, y would eff say ozo to 2+2=4, if ozo means yes, he should no, means ulu
pro Jesther
OZOOO OZOO OZOO OZOO
avain baxter
This doesn't make sense. Subscribe for more!
aqua phoenix10432
my head hurts
Abele Gigante
Basta!
Gilae` S 2.0
I still don't get it!?#?!
Rodrick Pascual
I didn't understand a single thing.
Majora12 _
This riddle is a paradox. Not knowing which is yes and which is no leads any Yes or No question to have a pointless answer. You either need to know what yes and no are or you need to know which one Eff is. However, we don't know either. Which is where your answer is flawed. If we asked Eff the statement "If I asked you if 2+2=4 would reply 'ozo'?" where ozo=yes then Eff would lie. He'd answer Yes or No depending on which is Yes. But this doesn't help us because then Eff answers Truthfully and Tee Answers Truthfully. While Arr could answer with yes or no. If Arr Lies we know it's Arr but if Arr answers truthfully we have no idea which is which. However, none of this matters without knowing which of the Two words Ozo and Ulu are Yes and No. If Ozo=No you still get Yes, which doesn't help at all. Because All you know then is Ozo=Yes or Ozo=No and you're back at the same place. Now if Ozo=no and we get the reply yes back from Tee and Eff then we know Ulu=Yes. Even if we asked them a question we know the answer is yes to we can't ask them if they would say yes or no because we don't know which is yes or no even if we get yes from the answer no matter what. Because Ozo=Ozo still to us and Ulu=Ulu Still to us. To ask a yes or no question we must first know yes or no. Otherwise are questions are meaningless, because we always get a true answer with two of them, and true doesn't have to be positive. If the true answer is no the answer is negative because No has a negative meaning. Which insinuates that sometimes the answer that is true can be negative. Once again leading us in a circle.
WhoAreYou
but thats making 2 question in one.. you ask if the guy on your left is arr and you also ask if he would say ozoo.. THIS IS CHEATING!!!
JoseAdrianSantaSam
I was understanding everrything until minute 1:09, afterwards it becaming confusing
Nia SmilesAllTheTime
Couldn't you just ask a question in the form of a double negative? So no matter which word you use the sentence would generate a positive meaning it wouldn't matter whether you knew what ozo or ulu meant?
WiseWordsOldMan
I actually solved it in five minutes. this is actually much easier than the others
Flashbax7
Can you not solve it by asking each one whether or not they are Tee? If they all give the same answer you know that word is the word for yes, if you get two of one word and the other then you know the one that appeared twice is the word for yes.
LucaLove YT
This still doesn't make sense...my brain hurts
AdaM R
bruh
goodhumourman
I like these videos but the guy's voice is unbearably annoying. Drink some water dude! Your voice is creaky as hell
Liliana Garza
ozo means yes because pause on 3:24
PeydaPete
The inscription was the liar. The gods were totally chill.
Martian 2040
I don't get it, hahaha
Gold Cuber
You said if they said ozo that ment the person on the left is tee but you don't know if ozo is yes or no
Androth
i thought you could only ask one question to each lord.
Kay Dee
You messed up the thought bubbles at 2:27 and made the truth telling Tee lie.
Livin' to Learn
There's something wrong with the puzzle...Consider the situation where the god whom you are asking the question to is NOT the one who answers randomly in yes or no.
Now, suppose you ask this god about what one of the other two gods would say about what the third god would say about whether or not his artifact is <artifact>. If the god you are asking this to is not the one who answers randomly, then one of the other two must be the random one. If this happens, then there is no way that the first god could ever answer your question because there is no way for any of the gods to know already what the random one will say.
PARADOX!!!!!!!!!!!!!!
Now, if the gods MUST answer ALL your questions, then it can't be because the random god will have to be not-random.
This also happens when you ask one of the gods about whether the random god say the truth when you ask him the next question.
soraninja
Sooo.... she can figure out enough alien language to ask questions .... but she didn't figure out yes or no ... hmmm seems kinda stupid. This is also assuming aliens use Human logic and understanding. I consider this riddle a failure.
Victor DaSilva
But what if you ask the first question to Arr? Then haven't you wasted a question?
Pilgrim AJ
Well, at least we know what to do if we get stuck on an alien planet with three gods with weird af names
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