Can you solve the famously difficult green-eyed logic puzzle? - Alex Gendler
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- čas přidán 15. 06. 2015
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One hundred green-eyed logicians have been imprisoned on an island by a mad dictator. Their only hope for freedom lies in the answer to one famously difficult logic puzzle. Can you solve it? Alex Gendler walks us through this green-eyed riddle.
Lesson by Alex Gendler, animation by Artrake Studio.
"There were no reflective surfaces"
*shows image of mad dictator with reflective sunglasses*
As if he would show himself to the prisoners
@@magnusnord8353 well he had to look at them....
@@magnusnord8353 also, you can't really see color all that well in sunglasses, unless they're one of those really reflective pairs.
I'm pretty sure those would change the color in the reflection
plus its an island which has water around it which is probably reflective.
Dictator: What is your statement?
Me: THE DICTATOR HAS REFLECTIVE SUNGLASSES
Then run!
yeah then run
XD it’s fair to cause they know he wears them but didn’t try it. Or just plug a sink and fill it look at your eyes
@Michael Baron Be Jesus and run on the ocean.
@@milo_south3670 You can’t know the joestar family secret technique!
Imagine being the only one without green eyes and on the 99th day everyone just leaves 💀
I imagined the same thing.
In that case no one will leave the island.
So all the prisoners go on the 100th night after confirming each other's eye color. So the confirmation comes from the fact that everyone stayed thinking all others have green eyes and they still stayed because they weren't sure of their eye color but were seeing all green color. Which would indicate that their eye color is also green. It takes 100 days to confirm for 100 green eyes prisoner. So even if 1 person has blue eyes, then none of them would leave.
No, I believe by induction that 99 prisoners would leave on the 99th day. The blue eyed prisoner would be left alone and could not escape.
HOWEVER it boggles the mind the level of mental record keeping those 99 prisoners would have to hold in their heads. “Perfect logicians”. Hrumpf! It’d never work in reality.
@@DavidSharma-ds actually, they would leave on the 99th night, because everyone else would just ignore their existence for the point of reference
But the LORD said unto Samuel, Look not on his countenance, or on the height of his stature; because I have refused him: for the LORD seeth not as man seeth; for man looketh on the outward appearance, but the LORD looketh on the heart.
1 Samuel 16:7, now how do we distinguish these people? Matthew 7:19-20 Jesus says Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.
God bless.😊😊
My brain understands this for about .2 seconds before getting confused again. It’s like trying to remember a dream
truee
I got the main part but I didn't understand how it would work for four, five, six people etc I had to write down exactly what the narrator said for three people and move all the numbers up one to understand it lol
@@sierrarose1512 Yeah I'm trying to figure that out. The statement was, "At least one of you has green eyes." At least one. That doesn't necessarily imply more than one, so how would Carl know he had green eyes? How would a fourth person know, if in that situation, everyone knew that everyone was seeing at least two pairs of green eyes?
Please help!
@@gerieconomides2776
The process of elemination is happeneing.
When there are 3 people:
Lets assume Carl's thought process:
On Day 1:
He can see person A and Person B have green eyes.
He also thinks that if he doesnt have green eyes both A and B can see it directly and completely eleminate him from consideration of "atleast 1 lerson has green eyes"
Now as per Carl, A is thinking that B has green eyes and since B can see A's eye color. If B sees A's eye color as NOT Green. He would have left immediatelty on Day 1 as he could see both of them non green.
Day 2:
Since B did not leave, Both A and B would realize that both of them have green . Since no body left out of them 2.
So as per Carl on day both should leave.
DAY 3:
As nobody left, Carl realizes that confusion still exists which can only occour when Carl also has green eyes.
All 3 of them will realize the same thing as nobody left and all have same thought process of each other.
On Day 4:
All leave.
Since end status is always nobody leaving.
And 3 people logic became 2 people logic because of elemination based on Carls assumption of him jot having green eyes.
When 4 people are involved, I believe it will come down to 3 people logic via elemination, then 2 people logic and final realization when no body leaves.
I verified 3 people logic while expressing here. I will think about 4 people now :).
Oh yes, its the same process of elemination.
If there are 4 people:
And Carl assumes that gis eyes are not Green.
Day 1:
He can see others are green and they can eleminate him from calculation which now turns the group into 3 person logic.
So as per Carl on 4th day, 3 people should leave.
If they dont leave on 4th day , it means the confusion is because his eyes are also green.
So on 5th day all leave realising the confusion is because everyone is green.
This is 4 person logic.
For 5 person logic:
First 5 days will be occoupied by 4, 3,2,person logic.
On 6 Day:
All leave as the confusion was not cleared until this day.
And so on.
Imagine Adria didn't have green eyes and Bill just wanted to watch the world burn.
If I was Bill I would watch the world burn outside of prison.
Imagine a situation, a guy wait happily with everybody until the 99th morning and find out everyone but him has left yesterday night.
DEAR GOD
@@stephydare8324 Oof, that would hurt.
Let it BURNNNN 🔥
Too much information for my 3 brain cells
Too much information for my three brain cells after using them all trying to understand buzzfeed unsolved
:/
Same lol
Everyone can see the reflection from the eyes so everyone can see what colour is the eyes.
so everyone should be out less than 90 days
This puzzle isn't too accurate xD
Question: would the sentence “everyone next to you has green eyes” be allowed? To each individual person, this is not new information. As a group, they would realize that if this is true for everyone, they also have green eyes.
That is just the same as the statement "At least 99 of you have green eyes", I think. I'm not quite sure, though.
That would be a new info imo. As that would mean that is true for any random YOU. Hence all of them.
True, also an answer
@@ashishtiwari87 In that case, "at least one of you has green eyes" is also new information. Any individual person knows that, but saying that to the group at the same time makes it new information.
@@Aviivix that’s not new information because they all know the others have green eyes. But saying everyone next to you has them means EVERYONE has them including you, which is new information
Adria: Do you have green eyes?
Bill: Ozo.
"Perfectly logical"
Yet no one tries to spill the water somewhere to see their reflection
okay dis is underrated
it is said that, they don't know what is "green"..
so how will they figure it out...
@@xiix-xcvii3421 They know what green is, they just don't know their own eye colour.
nhil gallanosa It’s not Said that but if they didn’t know why colour green is then all of this is moot
@@landofboobs8872 Remember they were raised here from birth so the might not even know what reflections are as the Dictator may not have taught them about it.
or just be like "lmao why y'all haven't left yet"
this is the smartest "solution" so far imo lol
Lol
Lol
Not a statement tho
🤣🤣
The original situation on the island is still weird to me. Every prisoner will see 99 pairs of green eyes at the meeting every day. But he/she might be the only blue-eyed prisoner. Nobody leaves, wouldn't you conclude most likely all 100 are green-eyed?
"Most likely" is not convincing enough for a perfect logician to risk their life
i agree with you this is best answer
If the perfect logicians are utilitarian, then they'll all just leave on the first night since the worst possible outcome is 1 person dies so that 99 can go free
what I dont understand is how 100 prisoners who cant talk to eachother start this little "experiment", yeah it makes sense with 2 prisoners but how do 2 prisoners rationalize this logic knowing there is 98 other prisoners on the island....
@@JakeRiversThey are all perfect Logicians.
For people still confused about how they got new information without you directly telling them new information, it’s because you say it to everyone collectively, effectively meaning everyone knows that everyone else knows that at least one person has green eyes. If you told them each separately without them knowing that everyone else was told the same information, they wouldn’t be able to escape. Once they all collectively know this, they all have that chain of hypothetical scenarios which goes until everyone except one person has red eyes. That one person with green eyes would leave on day one, but they don’t. Now you can see how they are able to communicate by either "leaving" or "not leaving". If we go back to the three-person example, if they knew everyone else's eye colour, but weren't allowed to know how many people were there on the following days, it would actually be impossible for them to all escape on the 4th day. Person A would only get as far as thinking "if I had red eyes they would leave on day 2" without actually being able to tell, because he wouldn’t know if they left or not on day 2.
what didn´t make sense to me about this riddle was that all of them knew that everyone else had green eyes, so it was literally, no new or useful information.
I figured out the inductive process, but still didn't know why they didn´t start this reasoning from the beginning (since they already knew the given information).
The real problem, if I get it right, is that they can see the eye color of people next to them AND count the amount of people, but not see the other people´s eye´s color.
If that´s the case, I think it should be made clear in the video. I stopped the video, didn´t see the answer last night, and under slept trying to figure it out because of that :´v
@@cristian-bull So annoying isn't it!? Why not say at least 99 of you have green eyes. That's not new info. If you had blue eyes everyone would leave you asap. They don't immediately so it's solved after that.
@@jort281 the new info is that the others also know that 99 have green eyes
I still didn't get that...
@@jensopink7240 imagine we are the only 2 logicians. You knew there was at least one green eye (which is me), but you don't what the world is like in my mind. After the visit, you now know that in my mind, there is at least one pair of green eyes(although you don't know if I can see them), and you can count on me to react upon it. "He now knows there is at least one green eye. If I am not a green eye, he will be able to know he himself is a green eye."
Meh, if I saw 99 other kids with green eyes Id also assume I have green eyes
id be scared shi*less !!!
lmao
If I've been there since birth, I'd assume all humans have green eyes at that point...
The dictator also has green eyes under the sunglasses
so true
I would have said "If I were you, I would leave tonight"
+wacka That would actually work. because Your not telling them to leave, your just giving an opinion that could go either way. But Opinions aren't always right, and the prisoners could of all realized that and not leaved.
+Baerto Meneguzzi
But your opinion is the same as new information, they didn't know it before.
+Яг вет интe Well, by that logic you can't even show your self infront of them (non the less speak), because then the new information is "I now know that you are standing there"
Slap Happy
Well well, but getting to stand in front of the children and speak to them had already been guaranteed by the dictator. This is about fooling the dictator with what you have. Would he really allow you to say "If I were you, I would leave tonight."?
Stating opinions would be very risky I'd say. An opinion like the one previously mentioned strongly implies facts unknown to the children, that they all can leave without problem. Also, phrasing it like an opinion would make the kids uncertain whethet it is true or not, which could go both ways.
Яг вет интe Ok, I get what you mean, and you're right about that. But if you ASK them "all the people with green eyes are allowed to go (they already know this) so why aren't you ALL just leaving?". Would it be legit or have you given them the information that you are wondering about this?
its amazing how the dictator made 100 perfect logicians without being one
Summary: the power of common knowledge is not only in what kind of knowledge or information the crowd gains, but also simply in the fact they receive or possess the information simultaneously or collectively. The latter itself disclose new information from the ostensible knowledge.
TRULY MIND-BLOWING!!!
"you cant tell them new information"
me, an intellectual: you all are allowed to approach the guard at night and ask to leave
but there's no certainty in you information. They wouldn't dare.
“You should slap everyone with green eyes”
@@Halo-lg7rq thats new information
SPx you’re right “you can* slap anyone with green eyes”
@VestedLove But that's the bullsh#t part. You can easily communicate using anything including your eyes or breathing, face mimicing.... If they are allowed to stare into each others eyes then you can easily tell to that person that he has a green eye.
Green eyed people: *exist*
Mad dictator: *and I took that personally*
And I took that person*
@@dimondeater5416 take my goddamn like or I swear I’ll actually take that person
You misspelled "person"
@@dimondeater5416She/He didn’t mean person they meant personally. “I take it personally that there are green eyed people living on this world.”, if you put it in a full sentence. Personally means he was offended by it, so she/he didn’t misspell anything and they didn’t use the wrong word.
@@moai567 They didn’t misspell anything, they meant to use personally, as in “I take it personally that green eyed people are here.” Personally means they felt offended by something, and what he/she meant was the dictator was offended by green eyed people existing, therefore, he/she didn’t misspell anything.
you could also say "everyone you see has green eyes." Then everyone would know that they themselves have green eyes. Even if the mad dictator gets mad, you would not have broken his rules.
Well, actually yes, they don’t know what the color green is, and when telling that to everyone, you would tell them something they didn’t knew.
@@electrolitdecharmander3555 y would the madman remove all mirrors if they didn’t know what green was in the first place?
@@j4nn4h4sh Maybe they know the green color exists, but do they know how is it? When saying “everyone you see has green eyes” they would know that the eyes’ color they’re looking at is green.
@@electrolitdecharmander3555 exactly. In that logic u wouldn’t need to remove the mirrors bcs they wouldn’t know if their eyes r green if they don’t know how green looks like, even if they can see their green eyes.
@@electrolitdecharmander3555 so they most likely already know what green looks like otherwise the madman wouldn’t remove reflective surfaces, which means it wouldn’t be new information to say everyone around them has green eyes
they could have reached the same conclusion without anyone having to tell them that at least one of the had green eyes. They already knew that and knew that everyone knew
i don't think the solution is actually correct.
On a large scale yes, it's hard to tell what changed. The new information doesn't come from the statement, it comes from the other's reaction to the statement.
The inductive part of the logic works without it, but the statement is required for the base case. It may seem like the case where there's only 1 green-eyed prisoner never has to be considered, but think of it this way:
For simplicity, there are 4 prisoners, A B C and D. All have green eyes. A sees 3 green-eyed people and thinks "if I had red eyes, then B would see 2 green-eyed people and think "if I had red eyes, then C would see 1 green-eyed person and think "if I had red eyes, then D would see no green-eyed people and think "oh, I have green eyes." ...
And then the logic carries itself back out. The important thing is that D's reasoning, even though it's in a hypothetical within a hypothetical within a hypothetical, is crucial to the real reasoning of A, and wouldn't work without the statement being made.
It was necessary to start the clock from which they all will start their calculation in silence. Repetation of this info acted like a start of a clock.
@@getthedunkon9347not reaction but lack of action (of not leaving after certain days)
Step 1: Confirm you have green eyes
Step 2: Realize this is the green-eyes riddle
or you could just leave since you already confirmed if you have green eyes or not lmao
Step 3: Ask Ted ed if you can leave
The answer is Ozo
Nice you got a cuddly
i love this reply section
imagine being a perfect logician while not realizing that 100 people can take 1 person easily
I imagine a dictator would have at least a few guns and guards (hence the guard tower)
@@freds233 sometimes, sacrifice will be needed
Hey, if Reznov and I could do it at Vorkuta....
The guy has the power to make you live without ever talking or seeing your own reflection, I'm pretty sure you're outclassed.
How did they become logicians without communication and grown up there from birth
“All water is in opaque containers”
Just, fricking, poor the water out!
TED-ed: “Can you solve this _ riddle?”
Me: no. probably not.
Honestly, if everyone around me had green eyes I wouldn't even think of the fact that another eye color could exist.
Edit: I'm going to stop responding to comments now, you all bring up valid points, but this wasn't meant to be a super well thought out comment lol
You aren’t a perfect logician though.
@@paulmahoney7619 That I most certainly am not, but do I need to be a perfect logician to make a CZcams comment?
But the dictator has red eyes which means you would know that people can have red eyes and think you also have them
You can see the dictator's red eyes and think ur eyes are red too
@@Tin_-lp8qm FATHE- I MEANT DICTATOR SIR, I DO NOT HAVE RED EYES DO I? I SURELY HAVEN'T INHERITED MY RED EYES FROM YOU
Ahhh.. So this is where every "green eye" meme started!
The origin 😂
yep, this is where it was born. and it’ll literally never get old.
what green eye meme
isn't it from the Disney main character thing...
@@_z-tl5un if you keep following the riddle videos of this channel you will see it in the comments. Not matter the challenge the people say something like "ok, is obvious: first confirm you have green eyes..."
@@someonesomeone8295 wat
Imagine all of this but some of randomly asks to leave as a guess and screws everyone
😂😂
But they all are logicians as per the narrator. So they wont opt for chance when they can come more closer to certainity or full certainity via logic.
Has anybody realized at 3:28, there are 101 people if you’d count up everybody shown on the screen?
GET A HOBBY
@@shikhagupta877 it doesn't take that long to count 101 things dude it's like a minute
@@17thstellation ratio
@@cathylin6140 indeed, it is 101:1. for every 101 counted there is 1 minute.
Similarly at 1:55 there are only 89 people if you count everyone on the screen
Why’d he raise them all to be perfect logicians...
He’s a mad man
cause he's maaaad
Idk
@@paulmahoney7619 What a madlad
to feed them to the demons, of course
I'd tell them, "don't worry, the volcano is a paid actor"
The dictator is bluffing about the eye search
that would be new information, though
That's new info
@@valentina5885 that new information has killed 15000000 braincells in every prisoner's brain, i think that is a fair price.
@@blauwbeer556 your joke just killed 15000000 of my braincells
Can’t they just dump water onto the ground to see their reflection?! Or what if it rains? 😂
I would've said"You can all go and ask the chief to leave" This would work because you wouldn't tell the anything new as they already know they can do it but they would realise that they can do it as can has two meanings-hope that makes sense
if you were the only one with different colored eyes, wouldnt people look at you like you are some kind of freak?
Haha
Nah, yeah that way they can actually do it in faster days
No....they don't know what color thier eyes are....actually they must think they're probably not green considering they're not tryna get out...
“They’re not one of us”
Heh. I find this funny, because in real life I do have green eyes. There was a time in my life when I lived among mainly Latino people, who almost exclusively have brown eyes. And, yes. When we made eye contact, sometimes I could see that people thought I looked like a freak. They were usually polite about it, though.
I'm just imagining a group of 100 people simultaneously asking a guard to leave the island and then all 100 packing themselves into 1 helicopter.
clown car? more like clown helicopter
this made me laugh so much😭🤣
Afghanistan today
@@andreinivchik5247 :((
@@andreinivchik5247 r/cursedcomments
Also I don’t have reddit
it's like induction axiom. if a statement holds true for P(n) then it should hold true for P(n+1) aswell
Imagine all going good for 50 days then one person gets mad and leaves the place to leave others in confusion
The Dictator's glasses = reflective surface
No they aren't, he can't see, not sure of your eye color, let you leave.
Ocean= reflective surface
Lol
They were opaque, so no.
what I was gonna say!
And then there would be that one idiot who wouldn't understand the logic
it would be me prolly because I didn't understand any of this-
All are perfect logicians.
I know this is true, but if they are truly perfect why did it take them so long to find out they all had green eyes
orig12.deviantart.net/6f13/f/2014/061/5/d/gumshoe_s_logic_by_1230james-d78nbq1.png
The 7th Apocalypse yep
This was such a good riddle
Love these. But you should wait between announcing the riddle and starting to provide a tip.
Props to the dictator for making 100 perfect logicians. He might be insane but hes a good teacher
Also somehow genetically breeding each of them to have green eyes specifically
@quinnmaster504 nope, the none green eyed babies got tossed into the volcano lmao
@amberwerwolfschool8927 That’s also artificial selection in a way
Imagine a situation, a guy wait happily with everybody until the 99th morning and find out everyone but him has left yesterday night.
That would be a devious thing for the dictator to do, he could simply move everyone into isolated soundproofed rooms so they all think everyone else left even though they're all still there.
Terrible English
@@siopaosoysauce yep. not that impressive. and knowing if how well you're doing in your second language is useful. how many languages have you learned?
@@siopaosoysauce Thanks for your understanding that English is not our native language. Though language ability can definitely affect our expression, I believe the ideas behind any language are more important.
@@hiimjustin8826 eleh kau mcm la reti bahasa org lain puihhh
3:00 I didn't get this at first, but understand what it meant after thinking for a bit, so here's a little extra explanation in case anyone else didn't understand!
At the start, the only reason someone would leave is if both of the other people have red eyes.
They all stayed.
Since Adria stayed, at least 1 of Bill or Carl have green eyes
Since Bill stayed, at least 1 of Adria or Carl have green eyes
Since Carl stayed, at least 1 of Adria or Carl have green eyes
At first this seems useless because each person can't confirm whether they have green eyes initially since they know both of the others have green eyes. However, the following night, they can then consider what would happen if they themselves had red eyes.
If Adria had red eyes, both Bill and Carl would know they have green eyes and leave the following night
If Bill had red eyes, both Adria and Carl would know they have green eyes and leave the following night
If Carl had red eyes, both Adria and BIll would know they have green eyes and leave the following night
However, none of them left the following day either, which would only happen if all of them had green eyes!
Thank you! I was completly stuck trying to understand the riddle and your help cleared the confusion!
can you please spell it out with 4 people? i understand 3, but i feel like with 4 people, it breaks down.
I had the statement "All the person you can see have green eyes", I'm not sure if that's "new information" or just using the fact that I'm not telling them every of them have green eyes
Just take one for the team
*”ALL OF YOU HAVE GREEN EYES”* then book it
in the case you did this, the dictator would change the rules and not let anybody out
you still die
That would be new information though
@@bdbailey surely 'at least one of you has green eyes' is also new information?
@@edstevens2772 No, because they all know that someone else has green eyes, they can see them
@@bdbailey therefore they don't even need that statement, they should be able to figure it out on their own. they are perfect logicians
Dictator: "All water is in opaque containers."
Me: "This is an island..."
The island is in an opaque container
Do you find seawater to be very reflective?
@@absdee91 Well ya
@@Bxll_Bxll Never been to an ocean huh? lol
Just throw out the water out of the container and look at urself like It ain't hard by the time night falls ur would have already left or when u bath or brush ur teeth
they can't talk but they could write things out, draw pictures, have a "green eye" sign in the courtyard and just start moving people to it. but that would involve trusting the others i suppose.
I just had a funny realisation. If you would do the exact same scenario with the exact same rules and the same statement given, but add one rule from the dictator.
If a prisoner doesn't want to go to the headcount they can decide to stay home and this will reward them with an extra piece of bread or something.
Then what you would see is that no prisoner would ever go to the headcount until after night 99 when suddenly everyone would show up for the headcount.
Then they realise everyone else is still there and they all leave on night 100.
“At least ten of you have green eyes” is equally as non suspicious but saves a ton of time.
@Frances Hogg are you familiar with logical induction? They cannot use that information to determine their own eye color before being explicitly told, because they dont have a base case. When you tell them all at the same time that at least one has green eyes, it synchronizes their knowledge in time and induction is only then valid.
It is a classic paradox that catches a lot of people.
@Frances Hogg I thought the same thing and they also already know that everyone at least sees 98 people with green eyes. The problem is that you can't be certain that everyone sees 99 until the 99th day after the outside person talks to them. Because after 99 days from when they were left there (but not told anything) each person must assume that even if they have brown eyes no one would leave on the 99th night because they are not certain everyone else is thinking about when they could leave.
Think about 3 people. Why wouldn't they simply all leave the 3rd night they are there? Because each of them thinks "I might have brown or green". But they don't know if the others see one or two green eyes. At best all they know is that the others see at least 1. But that's not enough information to act on. You have to be certain that if they didn't leave the 2nd night it's because you have green eyes and not because they themselves aren't certain. By being told at least one has green eyes then they can all freely make the assumption that leaving the second night was due to one other having brown eyes.
@Luis Hernandez this will only save ten days out of 100.
@Frances Hogg the outsider gives them a day to start counting from. they couldn't do this before because not everyone would necessarily count from the same day, or even count at all, because they can't communicate with each other
I said everyone adjacent to you has green eyes and that would get you all out on the first day
Ah, finally found the riddle everyone's referencing
Tell me please where do I stop the video in order not to see the answer
Thanks!
@@etoilefilante2110 1:53 I guess
@@alliumiao thanks a lot
More like 2:03 so you get a hint
@@lounajushpe4906 thank you but I deduced this hint myself and it didn't help much , this riddle is getting me
0:42 "There are no reflective surfaces"
The toilet in the back: Am i a joke to you
The girl: at least one of you has green eyes.
Me: sees everybody with green eyes.
Me: *starts doubting my color recognition capabilities*
you could have just told them "as you all already know, every prisoner you have ever met had green eyes."
Except they're not allowed to communicate, so they've never actually "met" eachother 👀
@@GucciStinkbug met, seen, samw thing. if they cant even look at eachother then no solution will work
That would make the guy 😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡
that is giving them new information
Albernas no it’s not. They’ve seen everyone else and knows everyone else has green eyes. So as they already know, everyone they’ve met has green eyes.
If I've been there since birth, I'd assume all humans have green eyes at that point...
Don't forget the dictator's eyes are red :) So are the sharks' lol
+Tùng Lê Sơn But they haven't seen dictators eyes and he said humans... It really should be told that they can understand what green is
+Stupid Kid I subscribed to you so please subscribe to me 😄😋
true
Cereal For Me Games
i did it as 1 of the prisnoners get a leaf and waved it to another prisnor and makeing a hole with his/her hand and covering his/her hand telling his/her that his/her have green eyes and repeat
I would’ve told them: “you’ve never seen anyone without green eyes”
That is extremely conspicuous
The dictator has red eyes.
assuming we reword this to "You can see 99 green-eyed prisoners", there are still problems with this, and they're quite interesting!
The main problem is in the word "you". Logically, you're making a different statement (asserting a different truth about the world) to each prisoner, which breaks the dictator's first rule. Even though each statement doesn't tell the listener anything new, it's still made up of multiple statements.
There are two things we can do to try and fix it. First we remove the subjectivity, and just express the totality of what we're stating (you may already see the problem with this, but hear me out). "Each of you sees 99 green-eyed prisoners." Unfortunately, this adds information to every prisoner who hears it - it directly tells them that they have green eyes. So we need to weaken the statement somehow.
Well, the strongest thing we can state without explicitly telling anyone they have green eyes is that "Each of you sees at least 98 green-eyed prisoners." This is like saying "there are at least 99 green-eyed prisoners".
But this is not that different from saying "there is at least 1 green-eyed prisoner"! The prisoners will go through the same reasoning, although they'll leave after waiting only a single day.
Pupils are reflective, so if you stare really hard into someone’s face you could see your eye color.
But I feel like there would be the uncertainty if the green was from your eyes, or from theirs.
They've been there all their life, they don't have a concept of what green looks like in the first place
Yeah i can see myself in my dog's eyes lol
Exactly what I thought 😂
Exactly what I thought 😂
I love how everyone’s turned this riddle into a huge meme and every time there’s another riddle there’s always someone who comments something related to green eyes
Gggggggrrrrrrrreeeeeeeeennnnnnn eeeeeeeeeyyyyyyyyyeeeeeeeesssss
They are meming it because everyone thinks they have green eyes
Same with a few other riddles too
“Can you rearrange the cube so that it can make the full journey?”
“Well, we can rearrange the cube so that it lands on planet 3, catching the criminals on our 2nd trip!”
“Yes, and I’ve also figured out how we can use the dark matter fuel most effectively.”
“We can also have other pilots to go a quarter of the way and refuel our ship mid-flight!”
“Though, do we press buttons A, B, C, D or E? The fuel gauge is spinning!”
“I don’t know, but I’ve got 6 crystals to time travel back in time in case it fails.”
“I assume you got those from our secret agent spying on the rival restaurants.”
“Yes, we had to infiltrate on the sixth floor as we figured the control room was there.”
“I also got the water levels to safe areas so the AI wouldn’t attack us.”
“Our other team of secret agents are currently removing Schrödinger’s cats so they don’t terrorize our space plans.”
“Ooh! While this probe is in orbit, we can laser-cut the purple blob so it only has acute sides!”
“We can also cut B-E, D-G, F-A, and H-C to cure the werewolf!”
“Well, if we’re going on the ship, we’ll need our instruments for the journey! Everyone, check the box with your own instrument!”
“Remember, just because the package has a red top doesn’t mean we need to check if an even number is on the bottom.”
“Uh oh… I pushed the button with a skull on it just to see what it did - everyone get out of the lab! The zombies are coming! We must get everyone across the bridge!”
“The passcode out is 2, 2, 9!”
“Send 2 groups of 3 that way, and a pair that way. I’ll go this way. Meet back here later, two of us are cursed to occasionally lie! Understand?
“Ozo!?”
“Well, at least one of us has green eyes. We can all cross the bridge if we have green eyes!”
“Now we need to get the lions and wildebeests across using the raft!”
Ozo
you didn't give them new information,but you did give them something to think and focus on.
In the hypothetical case where there is only 1 green-eyed prisoner, it actually does add information. It's subtle, but the prisoners figure it out by considering that situation.
Thank you :)
I would be the one prisoner that didn't think this through like everyone else did
same
300th like. Hahahaha, so many people would do the same.
Same
Then you would be dooming the other 99 lol
Kyle Lee no.... he'd just be stuck alone with the dictator
Step 1. Confirm your eyes are green
Ste-Wait a minute…
This is so underrated
Underrated.
Renee Park Perfectly balanced, as all things should be
@@thesaroscycle_archive this does put a smile on my face
Can someone explain
That was really exciting for me👌🌹 thanks
You know a riddle is forced when neither the ocean, some water in your hands and even other peoples eye-balls lack reflection.
Imagine being the one brown-eyed person on that island
Angela Hsiao sad
Or blue...
Then they all leave on night 98 without you 💀 imagine counting for that long only to realize that tou actually were the odd one out
@@teenyfroog6851sounds like a movie plot
Damn it Carl why you gotta be the third wheel
Carl is me in a nutshell :”>
Why you gotta assume? It could've been Adria for all we know
@@eddie246 OwO
Adria's the third wheel
Wha- u want the 3rd wheel to be a girl or what?
Shiny lilpup: *confirms that it has green eyes* asks to leave
Imagine being the only not perfect logician stuck on the island and you don't realize that you can leave so youre stuck alone.
or you take one for the team and shout "you all have green eyes,"
Meh, YOLO.
Remove the comma and put either a full stop or a exclamation mark
an exclamation mark*
or the dictator never said u cant bring weapons and kill the dictator and leave or stay cuz the island is dope now
But how would you know what the color green looks like
"I see the freedom in your eyes"- would make it easier, right?
that's so true! Lol
But thats new info
If ur wondering how
Green eye : freedom
See. Freedom. In your eyes = seeing green in ur eyes
Omg yasss
YOO THAT MAKES SENSE
Why can’t they just pour out some water from the bottle? Isn’t that also a reflective surface that they can look into?
0:43
Ted-Ed: *""...All water is in opaque surfaces...""*
Me, an intellectual: *_Proceeds to pour the water on the floor and use it as a reflective surface_*
You guys sure are intellectuals too...
Genius
@@dearaili
IKR
Thought of this too :)
@@kennethfernandes7430
Yup, there are many intellectuals in this world
The leader is wearing reflective sun glasses also eyes are reflective
Ted: there is no reflective surfaces
*Everyone on an island surrounded by water*
That's what I thought!!!
Their trapped inside a prison and maybe cant get out duh.
Lucid Dr3amer what? They are all outside headass
@@kenana5941oh, maybe i forogt whats 'walls'
@@Noz_h you're right, judging from the outside view of the island. But, no need to be smug and rude about it. 😂
So nobody tried pointing at their eyes, then the grass? Or something green at least.
Wooooow this is very good when you understand it😅
Thank you TED-Ed❤
I would've said everyone you look at has green eyes.
The only rule is that you can't tell people something they don't already know, and everyone knows that everyone they see has green eyes.
They wouldve realized that they must have green eyes because someone has looked at them. A lot simpler IMO
But aside from that, if they're on an island, why didn't they just look at their reflection in the water?
Nice!!
+Mariah W You just gave new information. Any individual (who thought they might have non-green eyes themselves) did NOT know that everyone they see has green eyes. Now that individual knows that everyone else sees everyone has green eyes.
Pete Nunez that would be something they figure out from what I said. I would say that everyone THEY (referring to each of them individually) see has green eyes. they would use logic to figue out that it applies to everyone else, just like they did in the answer the video gave
+Mariah W You are giving them new knowledge. They already know that everyone they see has eyes of the same color. By telling them what that color is, you have given them all the knowledge of what green eyes look like, thus giving them new information. They would not have to use logic to figure out that it applies to everyone else because you've told them that it applies to everyone else.
+Cameron MacDonald The prisoners already know what the color "green" is and what green eyes look like. That's not new information.
I would just look in the sunglasses of the mad dictator, and see my reflection
Yves Kummer That’s what I was thinking😂😂
Yves Kummer
I would just spill out my water, and see my reflection.
Everything is opaque, but I have another solution.
@@yesno1498 but you can see at day, then wait for night.
That would show you, who - a visitor - what the colour of your own eyes is. That doesn't help the people on the island, though.
Every couple years I come back to this to see if my brain has grown enough to understand it
"everyone single person in this assembly is, without exception, standing directly next to someone with green eyes"
The result:
They escaped because they have green eyes
But you have pink eyes so you cant leave
pinkeye means you have mould in your eye
Well yea
@Hellbanisher Rockz I know
@@cy.7493 bruh
mad dictator: makes sure there are no reflective surfaces and you can't talk to each other
me, an intellectual: *removes an eyeball to check if it's green or not*
edit: I understand that heterochromia exists, no need to repeat yourselves lmao
This is the best comment.
That... will hurt. a lot. And you'll be half blind... so it's not the best way...
@@jenjung577 I didn't say it was the best way, I just said it so you know your options
You , an intelectual, has heterochromia and is thrown to a volcano
@@porque6835 woo fun
This is where it all begins. The green damn eyes.
I love riddles like this
Imagine being such a dog that you just go up there and say "one of you has blue eyes"
That new information... so they couldn’t say that anyway
KevinXelegant It won’t be to those people
Izzy Grimes ooh good one
@@isabellegrimesey2426 Nice logic
@Isabelle Grimesey this might actually be genius, wow. The statement isn’t really new information cause it’s just a blatant lie and the ensuing deduction only takes 1 night instead of 100.
The only problem, though, is suppose one person did have blue eyes. Even if that were true, the 99 other people could NOT leave after hearing “one of you has blue eyes”. The only thing that told them is that they themselves do not have blue eyes, NOT that they have green eyes. For all you know there could be 98 green eyed people, 1 blue eyed person, and 1 brown eyed person (you) on the island. I think it would work if the statement was “one of you doesn’t have green eyes”.
I would have said "I wish you all the very best luck in escaping this island." But putting major emphasis on the "all"
Interesting idea, but some people wouldn't catch on. Also a more subtle point, is how would you be able to accurately see everyone's eye color? There are 100 people, and if the animation is "canon," so to speak, then you'd be on some announcement tower high above everyone else. Anyways, very interesting proposition.
Btw, technically there are no loopholes in yours, it's pure sneakiness
Is that not new information?
+Jozef B it's not new information at all, it's just words of encouragement
deirochimaru25 I wish you *AAAAAALLLLLLLL* the very best luck in escaping
Alright, I finally got my head around it by actually thinking through the different scenarios. So here is a clean explanation with a scenario of 4 people - A, B, C, and D
Scenario 1 - One set of green eyes, lets say A | A can see nobody has green eyes and so he leaves on first night
Scenario 2 - Two sets of green eyes, lets say A and B | A can see that B has green eyes, but nobody else has. He has two hypothetical scenarios
Scenario 2.1 - Only B has green eyes | in which case B would leave the first night
Scenario 2.2 - Both A and B has green eyes | in which case B would not leave the first night and on the second day, both of them realize they both must have green eyes
Scenario 3 - Three sets of green eyes, lets say A, B, and C | A can see that B and C have green eyes, but D doesnt. He has three hypothetical scenarios to contend with
Scenario 3.1 - Only B or C has green eyes | in which either one of them would leave the first night
Scenario 3.2 - Both B and C have green eyes | in which case, both of them would leave the second night (based on scenario 2.2)
Scenario 3.3 - A, B, and C have green eyes | once he realizes B and C have not left, it only means A, B, and C have green eyes and they all leave on the third night
Scenario 4 - All of them have green eyes | A can see that B, C, and D have green eyes. Now consider the above scenarios
Scenario 4.1 - Only B or C or D has green eyes | in which case on of those folks would leave on the first night
Scenario 4.2 - A pair of them have green eyes | in which case two of them would leave the second night (based on scenario 2.2)
Scenario 4.3 - Three of them have green eyes | in which case three of them would leave the third night (based on scenario 3.3)
Scenario 4.4 - A, B, C, and D all have green eyes | now, we can safely say that all have green eyes - since A can see that everyone has green eyes and if he didnt have green eyes they would have left on the third night. Which they didnt, meaning he also has green eyes.
Which is a weird way of thinking about this
omg thank you, this finally explained it. the video would be so much easier to understand if one line was added to the scenario with 3 people: after night 1, each of the prisoners now knows "at least 2 prisoners have green eyes"
Thank u i can finally go to sleep
3.1, 4.1, and 4.2 don’t need to be considered, because you specify that they can’t be the case in the scenarios
These logic puzzles are always so ridiculously contrived.
I love how logical these videos are and how unintelligent the comments are.
“Just crush him with the helicopter lmao”
Saying "Just Leave." or "You all have green eyes, you can leave." would've worked too, the fact that all the prisoners have green eyes could be discovered by themselves without communication so it's not new info.
The helicopter comments are smart too.
LMAO AT THIS COMMENT
Maiden of the Mist (for the second one) Except that’s not how that works. They don’t know they have green eyes, therefor telling them everyone has green eyes breaks the second condition, “you cannot tell them any NEW information”. Just because they could theoretically learn it doesn’t mean it isn’t new at the time
Noah Clark that one comment is above u for me lmao
Right below this comment
I would have said, "you can slap people you see with green eyes"
Everyone will receive a slap and then be free in less than 90 days
Edit: to those who really nitpicking and pointing out the flaws, realize that this is a joke.
Pharaoh Hamza Naqvi XXVII toche
My eyes are brown with green specks lel
Oryx, The Taken King XD perfect!
Damn that's a lotta slaps.....99 for each person.....that's gotta hurt
Oryx, The Taken King is that an information? Can we tell them one thing other than information?
hahahahhahahahahahhahahahahahhahahahahahhahahahahahahahhaha
“It is so lovely here! The trees are green all year here”
Trying my hand at all of these. I would tell them; "There's like, a hundred of you and only so may guards."
What if they were color blind
HAHAGAHAHAGA
Well if they were color blind then if they were raised and taught their colors, then wutever green looks like to them should still register as green
@@charlesbrownjr5618 this comment is incorrect on every level. Google what colour blindness is.
Charles Brown, Jr but red green colourblindness or whatever its called, both colours are gray
then they will think they are the only one have green eyes, maybe
“There are no reflective surfaces.”
The mad dictator’s sunglasses: O-O
If only he painted the sunglasses.
imagine seeing 99 green-eyed people and being like "ah yes, i totally don't have green eyes, makes sense."
Could someone tell me the name of the soothing music that starts before any TedEd video? It's so relaxing, just like meditation
and then I'll be the one person who is still at the island because I'm stupid
Lxxy C same
😂
Np in the beginning he said all people are logicians
ههههههه
Same tho
Why was this video entirely just the answer? There’s no moment to “pause to solve”
Nobody pauses anywya
this was not a ted ed riddle it was more of a logic thingie and yes
@@thalespro9995 I would, this is the only reason to watch these videos.
Just how boring is it to watch the answer directly.
Well if you really could came out with good statement I guess
Tacoman17 What
Wow this is amazing at so many levels my mind has been stuck for 30 mn. I don't think I ever utilized my brain more
They should've made a rule of 'No creating new opaque surfaces like spilling water or urine to name but a few so people in the comment section can shut up.
"After much pressure from human rights groups, the dictator reluctantly agrees..."
Oh wow, what power and influence from human rights groups!
Uh very similar to real life. Human rights groups really have no power. Otherwise the world would all have equal rights if human rights groups actually had real power.