Can you solve the famously difficult green-eyed logic puzzle? - Alex Gendler

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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.

[@avadadah6088]

"There were no reflective surfaces" *shows image of mad dictator with reflective sunglasses*

[@magnusnord8353]

As if he would show himself to the prisoners

[@NetheriteMiner]

@@magnusnord8353 well he had to look at them....

[@tinevodopivec9692]

@@magnusnord8353 also, you can't really see color all that well in sunglasses, unless they're one of those really reflective pairs.

[@MiniMia48]

I'm pretty sure those would change the color in the reflection

[@golddigger1196]

plus its an island which has water around it which is probably reflective.

[@x-tremefactory2542]

Imagine being the only one without green eyes and on the 99th day everyone just leaves 💀

[@MariaAbraham2010]

I imagined the same thing.

[@DavidSharma-ds]

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.

[@dtseng69]

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.

[@karlcole5617]

@@DavidSharma-ds actually, they would leave on the 99th night, because everyone else would just ignore their existence for the point of reference

[@JESUSISLORD.........]

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.😊😊

[@mao-janlin6751]

Imagine a situation, a guy wait happily with everybody until the 99th morning and find out everyone but him has left yesterday night.

[@medexamtoolscom]

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.

[@hiimjustin8826]

Terrible English

[@hiimjustin8826]

@@sawsawsuka yep. not that impressive. and knowing if how well you're doing in your second language is useful. how many languages have you learned?

[@mao-janlin6751]

@@sawsawsuka 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.

[@lockkeythetrickstar5359]

@@hiimjustin8826 eleh kau mcm la reti bahasa org lain puihhh

[@ahhhhhhhhhhhhsocool]

its amazing how the dictator made 100 perfect logicians without being one

[@marcelinebeckerrosas9023]

That's my favorite part in this kinda of puzzle xD

[@mrmurpleqwerty4838]

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.

[@xndybxyo]

clown car? more like clown helicopter

[@hithere9106]

this made me laugh so much😭🤣

[@andreinivchik5247]

Afghanistan today

[@xndybxyo]

@@andreinivchik5247 :((

[@pineapplejuice6954]

@@andreinivchik5247 r/cursedcomments Also I don’t have reddit

[@Imamotherfreakingavocado]

Imagine Adria didn't have green eyes and Bill just wanted to watch the world burn.

[@marcusscience23]

If I was Bill I would watch the world burn outside of prison.

[@stephydare8324]

Imagine a situation, a guy wait happily with everybody until the 99th morning and find out everyone but him has left yesterday night.

[@deathvideogame]

DEAR GOD

[@kylerivera3470]

@@stephydare8324 Oof, that would hurt.

[@hairpuff]

Let it BURNNNN 🔥

[@AbleRaxskall]

Props to the dictator for making 100 perfect logicians. He might be insane but hes a good teacher

[@quinnmaster504]

Also somehow genetically breeding each of them to have green eyes specifically

[@amberwerwolfschool8927]

​@quinnmaster504 nope, the none green eyed babies got tossed into the volcano lmao

[@ellotheearthling]

@amberwerwolfschool8927 That’s also artificial selection in a way

[@nikhilgarg9618]

Adria: Do you have green eyes? Bill: Ozo.

[@Startsu2837]

I was waiting to see a comment like this lmao

[@MaruMaruMaruMaruMaruMaru]

I didn't get it

[@_emmz]

This made me chuckle

[@_emmz]

​@@MaruMaruMaruMaruMaruMaruit's a reference to another of their riddle

[@Billy-q5s]

They’re not allowed to talk to each other though

[@ariella118]

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

[@paulmahoney7619]

You aren’t a perfect logician though.

[@ariella118]

​@@paulmahoney7619 That I most certainly am not, but do I need to be a perfect logician to make a KZbin comment?

[@pushpakesarwani4361]

But the dictator has red eyes which means you would know that people can have red eyes and think you also have them

[@Tin_-lp8qm]

You can see the dictator's red eyes and think ur eyes are red too

[@markernestdelacruz4895]

@@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

[@kirbycreep]

"Perfectly logical" Yet no one tries to spill the water somewhere to see their reflection

[@landofboobs8872]

okay dis is underrated

[@xiix-xcvii3421]

it is said that, they don't know what is "green".. so how will they figure it out...

[@roppis9258]

@@xiix-xcvii3421 They know what green is, they just don't know their own eye colour.

[@zahrah8512]

nhil gallanosa It’s not Said that but if they didn’t know why colour green is then all of this is moot

[@Jyuuu3u]

@@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.

[@samwise1530]

Dictator: What is your statement? Me: THE DICTATOR HAS REFLECTIVE SUNGLASSES

[@milo_south3670]

Then run!

[@aquaboi7818]

yeah then run

[@stevencarenduff2623]

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

[@kylerivera3470]

@Michael Baron Be Jesus and run on the ocean.

[@lxmber_wxtches5982]

@@milo_south3670 You can’t know the joestar family secret technique!

[@erikthehalfabee6234]

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?

[@ArthurKhazbs]

"Most likely" is not convincing enough for a perfect logician to risk their life

[@jovanljuna1111]

i agree with you this is best answer

[@pugsnhogz]

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

[@JakeLondonRivers]

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....

[@captainnomekop5056]

@@JakeLondonRiversThey are all perfect Logicians.

[@oatmeallover4302]

My brain understands this for about .2 seconds before getting confused again. It’s like trying to remember a dream

[@gabrielecanali1385]

truee

[@sierrarose1512]

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

[@gerieconomides2776]

@@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!

[@pavanshetty9806]

​@@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 :).

[@pavanshetty9806]

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.

[@asjakresevljakovic7988]

Too much information for my 3 brain cells

[@jazmin-bt4ub]

Too much information for my three brain cells after using them all trying to understand buzzfeed unsolved

[@jazmin-bt4ub]

:/

[@2h4]

Same lol

[@mahez4874]

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

[@mahez4874]

This puzzle isn't too accurate xD

[@qwerty-ye1hu]

or just be like "lmao why y'all haven't left yet"

[@willhblob1171]

this is the smartest "solution" so far imo lol

[@bonnie4283]

Lol

[@shely_D7vil]

Lol

[@shely_D7vil]

Not a statement tho

[@MrAYAAN2009]

🤣🤣

[@gutsandgears]

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

[@robertcane7432]

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"

[@jerekamarainen3604]

Thank u i can finally go to sleep

[@hrianboyer928]

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

[@paul7944]

yeah ​@@hrianboyer928

[@kurusegawa8064]

I thought of it like so, If I'm in a group of four, and I see three people with green eyes, I conclude that if my eyes are not green, they all leave on the third night. Let's say the three other people are named A, B and C. I think to myself that if my eyes are not green, person A will only see 2 people with green eyes, namely B and C. Now I think that in this scenario person A will think to himself "if my eyes are not green, then person B will only see one person with green eyes, namely person C, and they will leave on the second night" Why would B and C leave on the second night if they saw that me and A didn't have green eyes? If C were to be the only one with green eyes, B would expect to not see him anymore after the first night. But if C is still there after the first night, then B knows that there is one more person with green eyes, which would be him, and they would leave on the second night if B and C saw that neither me nor A have green eyes. This is what A would expect if he saw that I didn't have green eyes, and if he assumed that he doesn't have green eyes either. But when A would wake up the third day and see that B and C are still there, A would leave with them on the third night, if I were to not have green eyes. So on the fourth night we all leave together, if they are still there the fourth morning.

[@harsinsinquin4032]

“At least ten of you have green eyes” is equally as non suspicious but saves a ton of time.

[@Kirbyoh]

@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.

[@salbrismind]

@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.

[@mattkim96]

@Luis Hernandez this will only save ten days out of 100.

[@InezAllen]

@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

[@bigchungus9740]

I said everyone adjacent to you has green eyes and that would get you all out on the first day

[@scytri4882]

imagine being a perfect logician while not realizing that 100 people can take 1 person easily

[@freds233]

I imagine a dictator would have at least a few guns and guards (hence the guard tower)

[@buck7268]

Hey, if Reznov and I could do it at Vorkuta....

[@casperfiol69]

The guy has the power to make you live without ever talking or seeing your own reflection, I'm pretty sure you're outclassed.

[@MarioGarcia-io9gj]

How did they become logicians without communication and grown up there from birth

[@erusthaliel1568]

@@freds233 Someone should do a Lord Farquaad "Some of you may die, but its a sacrifice I'm willing to make"

[@hourofberries]

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

[@northfox5368]

Gggggggrrrrrrrreeeeeeeeennnnnnn eeeeeeeeeyyyyyyyyyeeeeeeeesssss

[@cubefromblender]

They are meming it because everyone thinks they have green eyes

[@DeathnoteBB]

Same with a few other riddles too

[@CCABPSacsach]

“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!”

[@Orange_Pear]

Ozo

[@abstract_guy1052]

This gave me nightmares as a kid

[@silverfish2315]

The Dictator's glasses = reflective surface

[@limecyanizer4394]

No they aren't, he can't see, not sure of your eye color, let you leave.

[@kaytk1762]

Ocean= reflective surface

[@sauceaddict9569]

Lol

[@mlrd6622]

They were opaque, so no.

[@mesmart8771]

what I was gonna say!

[@Kendall2727]

I would be the one prisoner that didn't think this through like everyone else did

[@oksananakonechna128]

same

[@RKD1010]

300th like. Hahahaha, so many people would do the same.

[@potatogames5410]

Same

[@kjl3080]

Then you would be dooming the other 99 lol

[@victoriah4278]

Kyle Lee no.... he'd just be stuck alone with the dictator

[@Kronman590]

Ah, finally found the riddle everyone's referencing

[@etoilefilante2110]

Tell me please where do I stop the video in order not to see the answer Thanks!

[@alliumiao]

@@etoilefilante2110 1:53 I guess

[@etoilefilante2110]

@@alliumiao thanks a lot

[@lounajushpe4906]

More like 2:03 so you get a hint

[@etoilefilante2110]

@@lounajushpe4906 thank you but I deduced this hint myself and it didn't help much , this riddle is getting me

[@iamphayvoured]

How about just saying “your neighbor has green eyes”?

[@danielrosenfeld4053]

"you cant tell them new information" me, an intellectual: you all are allowed to approach the guard at night and ask to leave

[@safe4547]

but there's no certainty in you information. They wouldn't dare.

[@Halo-lg7rq]

“You should slap everyone with green eyes”

[@SPxxxxx]

@@Halo-lg7rq thats new information

[@Halo-lg7rq]

SPx you’re right “you can* slap anyone with green eyes”

[@yelllowjacket1756]

@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.

[@merubindono]

Damn it Carl why you gotta be the third wheel

[@philscott1445]

Carl is me in a nutshell :”>

[@eddie246]

Why you gotta assume? It could've been Adria for all we know

[@Kevy707]

@@eddie246 OwO

[@mayaalvarez205]

Adria's the third wheel

[@PinkENBlue]

Wha- u want the 3rd wheel to be a girl or what?

[@morganthe2998]

Green eyed people: *exist* Mad dictator: *and I took that personally*

[@dimondeater5416]

And I took that person*

[@guywhochangeshisprofilealo7163]

@@dimondeater5416 take my goddamn like or I swear I’ll actually take that person

[@cplmoai]

You misspelled "person"

[@alaamhmd1158]

Lol

[@gettingshotsomeonesgonnapa8635]

@@teehee-3825 They were, in fact, joking.

[@nerox953]

0:42 "There are no reflective surfaces" The toilet in the back: Am i a joke to you

[@_moms_spaghettii]

I bet its sanded down lol

[@justinvanilla9785]

Meh, if I saw 99 other kids with green eyes Id also assume I have green eyes

[@rayflo9441]

id be scared shi*less !!!

[@user-ry1bb7wv8i]

lmao

[@Moosetapheles]

If I've been there since birth, I'd assume all humans have green eyes at that point...

[@theRPGmaster]

The dictator also has green eyes under the sunglasses

[@Tombee2]

so true

[@mouthlesshater]

Step 1: Confirm you have green eyes Step 2: Realize this is the green-eyes riddle

[@ngeechend4483]

or you could just leave since you already confirmed if you have green eyes or not lmao

[@MrJORFUS]

Step 3: Ask Ted ed if you can leave

[@hamzamemon3081]

The answer is Ozo

[@grambo1690]

Nice you got a cuddly

[@franchesca2418]

i love this reply section

[@SchokoFondu]

you could have just told them "as you all already know, every prisoner you have ever met had green eyes."

[@GucciStinkbug]

Except they're not allowed to communicate, so they've never actually "met" eachother 👀

[@robertwalsh1401]

@@GucciStinkbug met, seen, samw thing. if they cant even look at eachother then no solution will work

[@londonmason6129]

That would make the guy 😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡😡

[@kuro2899]

that is giving them new information

[@yeahkeen2905]

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.

[@Kur404]

This my friends is where the “green eyes” meme was born

[@hekr0029]

if you were the only one with different colored eyes, wouldnt people look at you like you are some kind of freak?

[@Mizraab2912]

Haha

[@jofx4051]

Nah, yeah that way they can actually do it in faster days

[@zeniashanze1882]

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...

[@davidbasa9985]

“They’re not one of us”

[@LamanKnight]

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.

[@mariakhan6090]

I'd tell them, "don't worry, the volcano is a paid actor"

[@akisa7865]

The dictator is bluffing about the eye search

[@valentina5885]

that would be new information, though

[@tuki897]

That's new info

[@blauwbeer556]

@@valentina5885 that new information has killed 15000000 braincells in every prisoner's brain, i think that is a fair price.

[@valentina5885]

@@blauwbeer556 your joke just killed 15000000 of my braincells

[@edgyraag3643]

Ahhh.. So this is where every "green eye" meme started! The origin 😂

[@nadian848]

yep, this is where it was born. and it’ll literally never get old.

[@_z-tl5un]

what green eye meme

[@someonesomeone8295]

isn't it from the Disney main character thing...

[@jessicav931]

@@_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..."

[@royhutauruk2432]

@@someonesomeone8295 wat

[@ChrisAsHell]

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

[@robertcane7432]

i don't think the solution is actually correct.

[@getthedunkon9347]

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.

[@soupgirl1864]

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.

[@pavanshetty9806]

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.

[@pavanshetty9806]

​@@getthedunkon9347not reaction but lack of action (of not leaving after certain days)

[@relic4948]

Just take one for the team *”ALL OF YOU HAVE GREEN EYES”* then book it

[@thepurified8386]

in the case you did this, the dictator would change the rules and not let anybody out you still die

[@bdbailey]

That would be new information though

[@edstevens2772]

@@bdbailey surely 'at least one of you has green eyes' is also new information?

[@bdbailey]

@@edstevens2772 No, because they all know that someone else has green eyes, they can see them

[@jackbagbaga6965]

@@bdbailey therefore they don't even need that statement, they should be able to figure it out on their own. they are perfect logicians

[@deirochimaru25]

I would have said "I wish you all the very best luck in escaping this island." But putting major emphasis on the "all"

[@chupacabra9357]

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.

[@chupacabra9357]

Btw, technically there are no loopholes in yours, it's pure sneakiness

[@jozef97]

Is that not new information?

[@anna-kt3zw]

+Jozef B it's not new information at all, it's just words of encouragement

[@lei916]

deirochimaru25 I wish you *AAAAAALLLLLLLL* the very best luck in escaping

[@callmegary2622]

If I've been there since birth, I'd assume all humans have green eyes at that point...

[@LePoseidon]

Don't forget the dictator's eyes are red :) So are the sharks' lol

[@ilmarivienamo2987]

+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

[@lpstolate1341]

+Stupid Kid I subscribed to you so please subscribe to me 😄😋

[@CerealGirl]

true

[@BigMikeNetwork]

Cereal For Me Games

[@zolv]

Instead of saying "At least 99 of you have green eyes" making the dictator mad, it can be said "at least 98 of you have green eyes". There is no new information as everyone sees 99 other prisoners with green eyes so "at least 98" gives no new information. Then after 2 days (instead of 100) they are gone.

[@LevelUpLeo]

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.

[@rjfrancisco7646]

That is just the same as the statement "At least 99 of you have green eyes", I think. I'm not quite sure, though.

[@ashishtiwari87]

That would be a new info imo. As that would mean that is true for any random YOU. Hence all of them.

[@LeBigPanda]

True, also an answer

[@Aviivix]

@@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.

[@seaweedbeach]

@@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

[@finfon2287]

Pupils are reflective, so if you stare really hard into someone’s face you could see your eye color.

[@summerjohnson2177]

But I feel like there would be the uncertainty if the green was from your eyes, or from theirs.

[@4c00h]

They've been there all their life, they don't have a concept of what green looks like in the first place

[@klowee5240]

Yeah i can see myself in my dog's eyes lol

[@jagadambika1590]

Exactly what I thought 😂

[@jagadambika1590]

Exactly what I thought 😂

[@wacka.]

I would have said "If I were you, I would leave tonight"

[@baertomeneguzzi9181]

+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.

[@zoushuu]

+Baerto Meneguzzi But your opinion is the same as new information, they didn't know it before.

[@zoushuu]

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.

[@ethant5605]

+Luna The rule was you cannot TELL them any new information. Technically if they see you and hear you, you're not telling them anything so no new information is given by them learning you can talk.

[@beidouvirus3978]

+R2Mintus It's not new because you see everyone as having green eyes, so it's already obvious to you that one of you has green eyes.

[@photon220]

So nobody tried pointing at their eyes, then the grass? Or something green at least.

[@user-vc8uz7lx1q]

That would tell them something they don't know

[@qwertyuiop.lkjhgfdsa]

@@user-vc8uz7lx1q no like between the prisoners

[@Bee_Draws-od5yy]

@@user-vc8uz7lx1q No they mean the prisoners signaling to each other

[@user-vc8uz7lx1q]

@@Bee_Draws-od5yy they're not allowed to communicate among themselves in any way

[@ornela7019]

"I see the freedom in your eyes"- would make it easier, right?

[@cerealbeforemilk8976]

that's so true! Lol

[@g0dly1]

But thats new info

[@g0dly1]

If ur wondering how Green eye : freedom See. Freedom. In your eyes = seeing green in ur eyes

[@ameliamarshall5377]

Omg yasss

[@crystalxxx_xplays28blogs98]

YOO THAT MAKES SENSE

[@angelaphsiao]

Imagine being the one brown-eyed person on that island

[@hpr2986]

Angela Hsiao sad

[@alexsabau5942]

Or blue...

[@teenyfroog6851]

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

[@Yao_Guai]

@@teenyfroog6851sounds like a movie plot

[@TheRandomizerYT]

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...

[@bananannaan]

Genius

[@TheRandomizerYT]

@@bananannaan IKR

[@kennyferds]

Thought of this too :)

[@TheRandomizerYT]

@@kennyferds Yup, there are many intellectuals in this world

[@skinnyjasper3097]

The leader is wearing reflective sun glasses also eyes are reflective

[@Stellarainn]

0:12 yes its called Cuba

[@osheridan]

Shout out to the 100 Cubans out there! Can't believe all 100 are perfect logicians

[@markmcflounder15]

😂😂😂😂😅 brilliant

[@peternebesny9712]

Dictator: "All water is in opaque containers." Me: "This is an island..."

[@Dramilos]

The island is in an opaque container

[@absdee91]

Do you find seawater to be very reflective?

[@Bxll_Bxll]

@@absdee91 Well ya

[@Selfg12]

@@Bxll_Bxll Never been to an ocean huh? lol

[@TSH425]

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

[@yveskummer6343]

I would just look in the sunglasses of the mad dictator, and see my reflection

[@zakdunbar2726]

Yves Kummer That’s what I was thinking😂😂

[@want-diversecontent3887]

Yves Kummer I would just spill out my water, and see my reflection.

[@nightshade570]

Everything is opaque, but I have another solution.

[@kaytk1762]

@@yesno1498 but you can see at day, then wait for night.

[@MyshaM.]

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.

[@keanureeveslusciousweave]

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

[@vabbysch]

This is the best comment.

[@jenjung577]

That... will hurt. a lot. And you'll be half blind... so it's not the best way...

[@keanureeveslusciousweave]

@@jenjung577 I didn't say it was the best way, I just said it so you know your options

[@porque6835]

You , an intelectual, has heterochromia and is thrown to a volcano

[@keanureeveslusciousweave]

@@porque6835 woo fun

[@RandomPerson-sh9tu]

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!

[@SSalvador9]

Thank you! I was completly stuck trying to understand the riddle and your help cleared the confusion!

[@robertcane7432]

can you please spell it out with 4 people? i understand 3, but i feel like with 4 people, it breaks down.

[@allisontaylor7287]

What if they were color blind

[@norahneo9770]

HAHAGAHAHAGA

[@charlesbrownjr5618]

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

[@Duck-wu3xy]

@@charlesbrownjr5618 this comment is incorrect on every level. Google what colour blindness is.

[@francisdimaano2350]

Charles Brown, Jr but red green colourblindness or whatever its called, both colours are gray

[@thaochu6955]

then they will think they are the only one have green eyes, maybe

[@matrixphijr]

"After much pressure from human rights groups, the dictator reluctantly agrees..." Oh wow, what power and influence from human rights groups!

[@LazyCrazyGuy]

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.

[@hufflepuff7479]

First of all Why did he make that rule

[@pinkbalm975]

1:03

[@julietta.m.t]

A fetish for green eyes I guess

[@discomacabre1]

He’s a nutcase

[@jinaiden]

Also me if I were on that island, looks through the reflection of the dictator's sunglasses

[@setfyo9959]

Cool riddle! Here's another solution that is blurry enough for the dictator not to get furious and yet everyone leaves after two nights. It works over beliefs themselves: "Atleast one of you thinks that all others have green eyes." After the first night, everyone who did not believe that all others have green eyes will have left the island, because they can be sure that there exists a prisoner other than themselves who knows that they have green eyes. Ergo, not leaving the island, entails the belief that all others have green eyes. Since no one left, everyone is sure that everyone believes that all others have green eyes and hence everyone must have green eyes. Finally, everyone leaves in the second night.

[@polskipatyk511]

Damn I dont know why you got 7 thumbs up when the slapping guy got 2.5k this is so smart

[@kjl3080]

Nice

[@prophet_alfredo9465]

@Jazmin Villanueva lmao so smart

[@eetuthereindeer6671]

I DONT FREACKING UNDERSTAND THE VIDEO OR THIS COMMENT

[@deepblue003]

Yeah It was mentioned in this video

[@crystalkittykitten5396]

hope people wont go too far to ship bill x adria...

[@siennal226]

I already did ship it. The minute I saw it, I said "I SHIP IT SO HARD" Heh.

[@crystalkittykitten5396]

+sienna l XDDDD you went too far my frend, too far. XD WHO AM I KIDDING?? O.T.P.

[@vainerre]

Adrill

[@figgysquag9208]

I HOPE CARL DOESNT AFFECT ADRILL

[@vainerre]

CAAAARRRLLLLL

[@jullitaczajkowska4200]

The result: They escaped because they have green eyes But you have pink eyes so you cant leave

[@cy.7493]

pinkeye means you have mould in your eye

[@jullitaczajkowska4200]

Well yea

[@cy.7493]

@Hellbanisher Rockz I know

[@cathylin6140]

@@cy.7493 bruh

[@a_disgruntled_snail]

These logic puzzles are always so ridiculously contrived.

[@straytype143]

0:06 just stop imagining

[@siquod]

But that would kill the prisoners instantly.

[@marcusscience23]

No, it would instantly set them free

[@cathylin6140]

Lol

[@ngolokante7805]

This made me lough out loud litterally

[@nadian848]

_a new meme has been born_

[@andreivoinea7343]

Or you could've just spill water on the floor ond Look at yourself.

[@pangarcher3554]

Lol

[@ravenwingthewarrior3859]

yes!!!!!!!!!!!!!!! so smaaaaaaaaaaaarrrrt!!!!!!!!!!!!!!!!!!

[@guilhermerafaelzimermann4196]

+Jkaybro Kattencrack flip container onto floor

[@guilhermerafaelzimermann4196]

Jkaybro Kattencrack good point, but they probably don't have sand in their rooms

[@NBACoDGaming]

+Jkaybro Kattencrack Thr containers don't matter, just spit it out on the floor

[@kenana5941]

Ted: there is no reflective surfaces *Everyone on an island surrounded by water*

[@alx2900]

That's what I thought!!!

[@Noz_h]

Their trapped inside a prison and maybe cant get out duh.

[@kenana5941]

Lucid Dr3amer what? They are all outside headass

[@Noz_h]

@@kenana5941oh, maybe i forogt whats 'walls'

[@jf2801]

@@Noz_h you're right, judging from the outside view of the island. But, no need to be smug and rude about it. 😂

[@bagybachi]

Love these. But you should wait between announcing the riddle and starting to provide a tip.

[@the7thapocalypse948]

And then there would be that one idiot who wouldn't understand the logic

[@thetoontastictoon1720]

it would be me prolly because I didn't understand any of this-

[@xwearenumber1x]

All are perfect logicians.

[@thegiovannimauro]

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

[@pokesurvivor3271]

orig12.deviantart.net/6f13/f/2014/061/5/d/gumshoe_s_logic_by_1230james-d78nbq1.png

[@LiLScunt]

The 7th Apocalypse yep

[@HeadCannon19]

Step 1. Confirm your eyes are green Ste-Wait a minute…

[@Tippex_Official]

This is so underrated

[@thesaroscycle_archive]

Renee Park Perfectly balanced, as all things should be

[@tronalddump6768]

@@thesaroscycle_archive this does put a smile on my face

[@thecount_zen]

Can someone explain

[@thesaroscycle_archive]

XENØRINE There’s a recurring meme in Ted-ed riddle comments sections where it’s Step 1: Confirm you have green eyes Step 2: Ask [insert antagonist of riddle here] to leave

[@ZetaCheese]

Why was this video entirely just the answer? There’s no moment to “pause to solve”

[@thalespro9995]

Nobody pauses anywya

[@FzeroVaporeon]

this was not a ted ed riddle it was more of a logic thingie and yes

[@vondralbra5147]

@@thalespro9995 I would, this is the only reason to watch these videos. Just how boring is it to watch the answer directly.

[@harveysantiago8872]

Well if you really could came out with good statement I guess

[@zahrah8512]

Tacoman17 What

[@Jmaniac9204]

I would’ve told them: “you’ve never seen anyone without green eyes”

[@theyormlad]

That is extremely conspicuous

[@charliedegiulio9951]

The dictator has red eyes.

[@soupgirl1864]

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.

[@jesuspereztorres1942]

"Kill those ones who don't have green eyes". Best case scenario: Nobody does it, everybody leaves. Worst case scenario: They kill me and the dictator for not having green eyes.

[@psi4262]

Thats new information 😂

[@deankaraniya7422]

That's an instruction, not a statement.

[@jesuspereztorres1942]

@@deankaraniya7422 but if nobody does anything, doesn't count as an order... I guess.

[@stevencarenduff2623]

Uhhhhhh I have slight heterocromea so one of my eyes has a tint of green so idk if I count

[@trickytreyperfected1482]

@@jesuspereztorres1942 it's still a command even if no one follows it.

[@noahclark7603]

I love how logical these videos are and how unintelligent the comments are. “Just crush him with the helicopter lmao”

[@maidenofthemist9423]

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.

[@wewewewewewewewwewe]

LMAO AT THIS COMMENT

[@thedinopug]

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

[@quackatitty7430]

Noah Clark that one comment is above u for me lmao

[@Bob-aaaaa]

Right below this comment

[@gd_jinx2544]

This has been turned into a meme in almost every single Ted-Ed comment section lmao Edit: wow after six months of dead comment this somehow pops back and gets 1k likes lmao

[@samiabed2206]

yaeh

[@giacomovillani6190]

I came here exactly to know this meme

[@josephanthonyaguinaldo3280]

Haha lol

[@4xJcakBC]

That's why we're here 😅

[@bluina5974]

what has?

[@interopsty]

imagine seeing 99 green-eyed people and being like "ah yes, i totally don't have green eyes, makes sense."

[@carleigh.charlton]

if they have been on the island since birth and they can't ever talk to anyone how would they have ever learn English or any language for that matter. how would they understand the sentence you told them.

[@nutzworth9094]

Carleigh Charlton I agree. Though, if the dictator schooled them, they'd know, but couldn't tell anyone that they did.

[@leolaserbolt]

Carleigh Charlton shush you plot holing commenter.

[@fizzii5072]

Carleigh Charlton they are perfect logicians.

[@pebritryastuti7481]

Carleigh Charlton thats exactly what i thought! if they cant talk to each other how do they learn the color at all!

[@crazy4bricksthebrickbrothe722]

There is clearly some education in the prison if they are expert logicians.

[@jackclements5026]

or you take one for the team and shout "you all have green eyes,"

[@linky6452]

Meh, YOLO.

[@cyberauxi9375]

Remove the comma and put either a full stop or a exclamation mark

[@Foxzor1337]

an exclamation mark*

[@cesarflores1224]

or the dictator never said u cant bring weapons and kill the dictator and leave or stay cuz the island is dope now

[@Bobbiejoe]

But how would you know what the color green looks like

[@mortmort97]

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?

[@tchudson75]

Nice!!

[@nnzfmly]

+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.

[@mortmort97]

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

[@cameronmacdonald8394]

+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.

[@AsianNinjaGod]

+Cameron MacDonald The prisoners already know what the color "green" is and what green eyes look like. That's not new information.

[@trackandhp7]

What I don't understand is why they would have to wait 99 nights? Why not leave after the first night if they were all watching each other?

[@lxxy05]

and then I'll be the one person who is still at the island because I'm stupid

[@professorphoenixia1245]

Lxxy C same

[@Dianlove-l8t]

😂

[@shivanshaggarwal2964]

Np in the beginning he said all people are logicians

[@TheMajedtion]

ههههههه

[@zachb2838]

Same tho

[@attenonmj3708]

"So how did you outsmart the dictator?" Idk, I apparently outsmarted myself.

[@ingelegenial]

Best comment yet. Because it's so true

[@NovaGalaxia02]

Am I the only one thats watched this riddle like a thousand times yet still forget how to solve it?

[@cricketknowall]

I have a feeling the solution isn't correct

[@NovaGalaxia02]

@@cricketknowall what do you mean tho

[@carsonbrown4555]

Same

[@slm0nw174]

@@cricketknowall exactly, there are soem major holes in it, like the fact that telling them at least one of them has green eyes doesn't vhange anything as they already know that, so they would've been able to get out without any help

[@ean627]

@@slm0nw174 but they dont know that either

[@ShadowP0s5ess1on_A]

Me: you all have green eyes 1:21

[@Awhan..]

it is a new information

[@ImmortalityVenerable]

​@@Awhan..It is not new tho it only they didn't know the info. It was always there. Fault of the supervisor.

[@SatvinderSingh-s8x]

​@@ImmortalityVenerable hey man !! They don't know, He himself has green eyes😂 Thus it's a new info.

[@Cacuofa]

You may all leave the island.

[@eliozyndias]

well, it is explained at the end. there’s a dictator and u need to play it safe.

[@KingA-jl2jq]

Imagine being such a dog that you just go up there and say "one of you has blue eyes"

[@Kevinxelegant]

That new information... so they couldn’t say that anyway

[@KingA-jl2jq]

KevinXelegant It won’t be to those people

[@KingA-jl2jq]

Izzy Grimes ooh good one

[@NguyenHoa-ww5gl]

@@isabellegrimesey2426 Nice logic

[@mattkim96]

@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”.

[@mr.t5899]

“There are no reflective surfaces.” The mad dictator’s sunglasses: O-O

[@carolmarcelo2445]

If only he painted the sunglasses.

[@rivereatswords]

funny, i thought the “one statement” should be “none of you has ever seen a non-green-eyed prisoner”. saves everyone 100 nights.

[@NovaGalaxia02]

or like 'everyone around you has green eyes'

[@rivereatswords]

@@NovaGalaxia02 yeah

[@IkBenHetLekkerNiet]

That was what I was thinking!

[@Rodrongo]

That is new information

[@zbdmo4914]

@@Rodrongo how is that new information? I'm genuinely confused.

[@Harsh1t_singh]

My statement WE ALL ARE SAME, IN LITERALLY EVERY ASPECT

[@HakarDoski]

"all water is in opaque containers" have you tried pouring the water?

[@VioletNKisHere]

Yeah these riddles has problems.

[@yingjiawan2514]

@@VioletNKisHere These are just logic riddles. The added conditions are just to make the situation more realistic. The scenario is very arbitrary and can be subject to millions of versions. Guards, prisoners, dictators, etc…they are irrelevant to the logic puzzle and only added so it helps you to think less abstractly.

[@VioletNKisHere]

There still under solutions and besides these riddles are memes. We like making fun of them

[@fwoop4848]

ikr, and does the ocean not exist in this riddle. They can take some ocean water and see their reflection in it

[@zesnowpea6347]

@@fwoop4848 but there’s a giant wall stopping them from seein the ocean

[@no_handle_found]

I would have just said "In my eyes everyone is equal"

[@soni-switch5207]

Hasvshsjdhsgwgsvcfhuyrga

[@tausenrico126]

It is new information tho

[@gulgaffel]

@@tausenrico126 not really, but it doesnt really make the logicians 100% certain that they have green eyes.

[@NoNameC68]

Don't worry about the plausibility of the islanders figuring out the solution. Instead, focus on how the solution is technically possible. It can be hard to grasp at first, but it's easier to figure out when you look at every possible solution. Hopefully the following makes sense: Look at each scenario from both a green and non-green eyed perspective. Keep in mind, you know at least one person has green eyes. Below, I will list 3 different Day 1 scenarios and their possible conclusions. Day 1: A. You notice the other 2 residents have brown eyes. You deduce that you must, therefore, have green eyes. You leave that night. B. You notice 1 resident has green eyes and the other has brown eyes. You can't deduce your own eye color. C. You notice the other 2 residents have green eyes. You can't deduce your own eye color. Day 2: Ba. You wake up in the morning, the person with green eyes left. They deduced they had green eyes, meaning you and the other resident had non-green eyes. (See A. for that person's perspective) Bb. You wake up in the morning, the person with green eyes is still around. This means the green-eyed resident saw someone else with green eyes. Because the other resident has non-green eyes, this means he must have witnessed your green eyes! You leave that night. (The other green-eyed resident will also leave that night having used the same deductive reasoning as yourself!) C. Because the other 2 residents have green eyes, neither of them could deduce their own eye colors on Day 1. Both are still present. Day 3: Ca. You wake up and both the other residents are gone. This means they were able to deduce their eye color (see Bb for their perspective.). Because of this, you know you have non-green eyes. Cb. You wake up and both the other residents are present. Because neither of them left, it means they weren't able to deduce their own eye color. This means on Day 2, they saw the same thing you saw - that each other person had green eyes. This is only possible if all of you had green eyes! You leave that night, along with the other 2 residents. Adding a 4th person does not change the process of elimination. Try it yourself! In fact, you'll notice a pattern that simplifies the process of elimination! If you see x amount of green eyed people, then they won't leave until either x days, or x+1 days - depending on your own eye color. For example, if you see 7 green eyed people, then they'll stick around for the first 7 days. If you wake up on day 8 and they're gone, then you have non-green eyes. If you wake up on day 8 and they're still around, then it means you have green eyes and you're safe to leave that night! The weirdest thing is, all the other green eyed people will be figuring it out at the same time as you!

[@amrishsurajbally4661]

+NoNameC68 I’m responding to you as your answer as I believe it is well laid out and did an excellent job in conveying what the video is stating. I do not agree with it however, due to the following. Day 1 “A” is not possible as you will be seeing two persons with green eyes and therefore the other two persons will be seeing at least one person with green eyes. Day 2 “Ba” will not be possible due to the above. Also your statement “Bb” - “Because the other resident has non-green eyes, this means he must have witnessed your green eyes!” means that you have to see a non-green eyed person for it to move to a two person situation, which is not the case. And “Ca” is only possible if you have non-green eyes, which is not the case. What I conclude is that a three person scenario can move to a two person scenario only if one person actually has non-green eyes, if not, it is not possible to deduce whether you have green eyes.

[@NoNameC68]

Amrish Surajbally I think you may have misunderstood the format of my explanation. Each scenario describes how many people you see with green/non-green eyes if you were one of the residents. You explained that Day 1 "A" is impossible because you would see 2 people with green eyes. But I wasn't describing a situation in which every resident has green eyes. I was describing a situation in which only one resident, you, has green eyes. This makes Day 2 "Ba" possible. ” means that you have to see a non-green eyed person for it to move to a two person situation, which is not the case." Actually, this is precisely the case. As I said before, Each scenario consists of different perspectives in different scenarios. In some scenarios, only 1 person has green eyes. In others, 2 people have green eyes. And in the last scenario, all 3 people have green eyes.

[@TheJonathankang]

+NoNameC68 Well constructed, too bad I'm too lazy to go through this whole deduction process in my brain. So I thought maybe everyone can just write down what they see on the floor in an orderly fashion, and formulate it into a chart with names indicating whether the person with the corresponding name has green eyes? Logician no.1 writes down the green eyed people with their names she(he) sees on the floor. Logician no.2 writes down the green eyed people with their names she(he) sees on the floor. Logician no.3 writes down the green eyed people with their names she(he) sees on the floor. . . . . . Logician no.100 writes down the green eyed people with their names she(he) sees on the floor. Once the graph is formulated, they will form a consensus on who has green eyes and who doesn't.

[@markdaniel8740]

why wait eight days?

[@DNAeternal]

+NoNameC68 "0:18 Any prisoner CAN approach the guards at night and ask to leave." This rule says they CAN, not that they MUST when they find out the truth about their eyes color. So, if you had 3 people: 2 of them had brown eyes and one of them had green eyes, the person who had green eyes could realize his eye color and decide NOT to necessarily leave the first night. DAY 2, Bb You wake up the second night and see that the person with green eyes is still there along with the brown eyed person, how do you know for certain that the green eyed person didn't just decide to skip a night when to leave?

[@StudiesOnly-l4c]

Imagine all going good for 50 days then one person gets mad and leaves the place to leave others in confusion

[@puzzLEGO]

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.

[@cristian-bull]

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

[@jort281]

@@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.

[@patrikbede8950]

@@jort281 the new info is that the others also know that 99 have green eyes

[@jensopink7240]

I still didn't get that...

[@testack8806]

@@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."

[@L-Main]

That moment when everyone leaves on the 99th day, because you don't have green eyes

[@nfrigoli1990]

Depression!

[@francescof3267]

so saaad =( ahahah

[@adeleaccant7056]

oof

[@princeofexcess]

I see one flaw. I dont think the puzzle states that the logicians themselves know that other people in the prison are also perfect logicians. Unless I missed out on something? Without this knowledge you cannot be sure that you can rely on other people making the right choices.

[@albertzhang5699]

princeofexcess Lets not worry about that...

[@danodet]

princeofexcess Your right that something is missing but what you are suggesting is not enough to make the puzzle solvable. Here are some suffisant statements1) all the prisonners are perfect logicians2) all the prisonners know that all the prisonners are perfect logicians3) all the prisonners know that all the prisonners know that all the prisonners are perfect logicians...100) all the prisonners know that ... all the prisonners know that all the prisonners are perfect logiciansA stronger and simpler statement (also suffisant) is to say that : all the prisonners are perfect logicians and this is common knoledge.

[@princeofexcess]

danodet why isnt the knowledge taht all prisoners know that all prisoners are perfect logicians sufficient?

[@danodet]

princeofexcess Suppose there are only two prisoners and you are one of them. After one days the other one is still there. If you know that he is a perfect logician than you can conclude that he did not left because you have green eyes. If you don't know that the other is a perfect logician you can't make a deduction with certainty. Now suppose that there are only three prisoners and you are one of them. After two days the other ones are still there. If you know that the others know that others are perfect logicians than you can conclude that they did not left because you have green eyes. If you only know that others are perfect logicians you can't make a deduction with certainty. This is all because you rely on other's logic. And themselves are relying on your logic. This is called modal epistemic logic. Every puzzle of this type (like the Freudenthal problem) seem to miss that point.

[@princeofexcess]

danodet Alright so you need 2 things all prisoners know that other prisoners are perfect logicians and all prisoners know that other prisoners know that the prisoners are perfect logicians.

[@surgeonsergio6839]

Honestly what statement to make is more of the real puzzle than the actual thing.

[@penguinvader7057]

1. You can only make one *statement*. 2. You cannot *tell* them any new information. Therefore, if you use a non-verbal way (so it isn't telling) to ask (so it isn't a statement) "Did you know that you all have green eyes?", you don't technically break the rules, and all of them get out that night.

[@MohakSumaria]

Penguinvader Yea well that way you can wriggle your way if it was a court but very unlikely when it's a dictator.

[@hyperhumana]

Penguinvader is this a statement? In logics stetement must be true or false.

[@MohakSumaria]

Penguinvader And as hyperhumana said any statement in logic is only either true or false, and "you can make only one statement" does not mean you can say or ask or utter any number of non-statements.

[@noamtashma2859]

If they're truly perfect logicians, they would know that you asking something doesn't necessarily mean anything. You could try to tell them that your only possible reason to ask such a question is to give them the information. But that would fail horribly because they do not know if you're a perfect logician, and non-perfect-logician people can do things without a reason, so you might just be asking a very stupid question. And then there's the angry dictator running after you I wouldn't do that

[@subh1]

Penguinvader But then that becomes an uninteresting no-brainer. And mathematicians/logicians are a tad bit more interesting than that. :)

[@Veggite1]

This only works if the prisoners know what color corresponds with the word "green". There is however a way to release all of the prisoners immediately after your statement, even if they don't know what "green" is. If you tell them "Only one of you has green eyes" then every prisoner, knowing that all of the other prisoners have the same eye color, will know that the only single prisoner that has green eyes is his/herself. Every prisoner will then ask to leave. The dictator would know that your statement is false, so it would not be considered new information.

[@DohLLe]

+Nunon osos for this actually makes sense

[@uknownada]

They all know what the color green is. They know everyone else has green eyes. What they DON'T know is what color their own eyes are.

[@matthewclayton6733]

+Nunon osos for That is actually a good point. Like if they don't understand what color corresponds to the word "Green" then a prisoner would look at everyone and see that the all have the same color eyes. So this prisoner seeing that everyone has the same color eye would think that they are the one who has the one differently colored eyes. Since you told them that at least ONE of them has green eyes, they'd ask to leave. This would be true for all of them and everyone would end up leaving.

[@uknownada]

Matthew Clayton The puzzle WOULD be easier if they didn't know the color green. It's a good thing they actually do as the puzzle very clearly explains, so this isn't a solution at all.

[@uknownada]

The puzzle clearly states that the prisoners know what the color green is. I honestly don't understand how people think this solution could work.

[@zentifygaming8394]

Caution: this only works if everyone is smart *im about the ends this whole prisons escape*

[@jaacobb123]

They said theyre all perfect logicians. Theyre all very smart.

[@Neonlaserz]

@@jaacobb123 I agree, but the first time I watched the video I also missed that part. :/

[@Un_k_noWN]

all you did was end English

[@andrewandrus3296]

@@Un_k_noWN thank you

[@osuremi7432]

@@jaacobb123 Why no one notices that is missing a condition: that they KNOW ABOUT THEMSELVES that they are all perfect logicians. Why isn't stated anywhere this thing? Otherwise how the f**k one can think that all other 99 will think in the same way?

[@elfinthekitchen]

"The dictator allows you to visit the island." Me who has green eyes: 👀

[@girl-in-grey]

Them: No reflective surfaces Me: *Proceeds to polish rock*

[@stevencarenduff2623]

Me: *looks into the dictators sunglasses*

[@littlevirus3562]

Me, a smartass: *looks at toilet*

[@princyantony2566]

Me: goes to the seawater and finds out the truth

[@rcoverc]

If I was a prisoner i would walk to people and frantically point to their eyes and give them a thumbs up, so they would know that they have green eyes. Then they’d return the favor. We’d all win

[@blankness8]

Lmao me, I have no sense of logic whatsoever 😂

[@ketereissmore3967]

How do u let them know a thumbs up means they have green eyes,when u all aren't even allowed to communicate verbally?A thumb up can mean many things.

[@blankness8]

@@ketereissmore3967 Well, I think OP was assuming (logically) that everyone's worried what color eyes they have. It would be constantly on their minds, "I can be free if I have green eyes, but I can't tell!". So when someone walks up to you and frantically points are your eyes and gives you a thumbs up several times, chances are you'll think you have green eyes.

[@ketereissmore3967]

Sure that the first possible meaning pop up to ur mind after seeing the thumb will be what u just said,but the situation also quoted that "they will leave the island only if they're sure about their eye colour",I don't think any of them will leave the island just by that thumb up since there's still a rather high possibility for it to have an alternate meaning.

[@blankness8]

@@ketereissmore3967 True, true. I wouldn't have enough confidence in anyone to just trust that.

[@oryxthetakenking8275]

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.

[@goldgamez8843]

Pharaoh Hamza Naqvi XXVII toche My eyes are brown with green specks lel

[@frenzied3478]

Oryx, The Taken King XD perfect!

[@tanmoybhattacharjee2439]

Damn that's a lotta slaps.....99 for each person.....that's gotta hurt

[@grrr1351]

Oryx, The Taken King is that an information? Can we tell them one thing other than information?

[@adventurecraft_6_yt817]

hahahahhahahahahahhahahahahahhahahahahahhahahahahahahahhaha

[@apokalypthoapokalypsys9573]

How about this statement: "You can ask the guard to leave." There is no new info here, since a person CAN indeed ask the guard to leave, just keep in mind it may fail. However, hidden in that statement is the implication that doing so is safe, so all prisoners would leave (if they trusted us, and the riddle assumes they do). Then again, I wouldn't get the head start and the dictator would probably catch me.