(The scenario will be presented in first person, to get rid of the ambiguity of the "all-knowing third-person")
Scenario: I and 50 of my best friends, relatives, and people I trust, are standing around 2 empty cup in my kitchen. A man (I do not recognize him) walks into the kitchen, holding a vacuum sealed package containing one of these cyanide test kits. He then proceeds to fill up both glasses with water from my sink, take a pill out of his pocket, and drops it in the left cup. He then uses a cyanide test strip in the left and right cups- the one on the left comes up positive, while the one on the right comes up negative. He then tells I, and the 50 people around me, that we must drink from one of the cups, or he will kill all of us. The 50 people around me go first, and they all drink from the left cup, the cup I saw the cyanide pill go in. They all then turn to me, and tell me to drink from the left cup. I am not given the opportunity to ask them why. Edit: For arguments sake, let's assume it takes an hour to see the effects of cyanide poisoning.
Question: Which cup should I drink from, if I want to survive? Follow-up Prove that you should drink from that cup. You can use any logical system, or any other probabilistic analysis- but you cannot simply say "There's a better chance to survive drinking from cup X"
I was arguing this out with a couple of friends for hours, but since none of us can really appeal to an argument constructed from premises we all agree on, we weren't able to convince each other. More than I would want to hear that I am correct, I would want to be shown definitively which answer is correct
This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
The truthfulness of the cyanide pills and the cyanide strip cannot be verified. The mysterious man could be lying, or could be using faulty pills/strips. You can't know for certain.
The fact that your bros didn't die can be verified.
Probably wait like 10 minutes in case it takes a while for the cyanide to kick in. If no one dies, grab the other cup and throw it at the dude's face.
Drink from the right... it has no unknowns assuming everything to be told is told and there was no "you didn't notice he dropped a mysterious powder in the right cup"
The cup was in your kitchen, so I'd assume it was your cup that you know where it came from and where it has been. The water is from your sink and the man did nothing with it.
With the rather absurd nature of the question, I don't know if the time factor can really be played... but as people above have mentioned, if the first person is not dead yet by the time a 50th drinks... it is either not cyanide or the miniscule amount you actually get from less than 1/50th a cup of water is not life threatening. However, this method still presents unknowns... and even more of them than if you had been the first to drink because now 50 people have touched that cup while leaving the right one perfectly alone.
Both cups are poisoned. I've seen this movie before.
The left cup is poisoned with some non-cyanide poison that was on the test strip, perhaps a slower acting one to give people the illusion that they're safe, while the right cup is poisoned with cyanide.
If he's gone to the trouble of getting a cyanide pill, him re vacuum sealing the cyanide test kit after poisoning it would not be out of the question.
Moral of the story: Never mess with a Sicilian when death is on the line
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
On February 05 2014 11:43 lichter wrote: The truthfulness of the cyanide pills and the cyanide strip cannot be verified. The mysterious man could be lying, or could be using faulty pills/strips. You can't know for certain.
The fact that your bros didn't die can be verified.
Probably wait like 10 minutes in case it takes a while for the cyanide to kick in. If no one dies, grab the other cup and throw it at the dude's face.
Fine, fine, I'll add that you don't have enough time to see what happened...
I don't get it. If he didn't do anything to the cup on the right and it tested negative, shouldn't it be ok? Even if other people use the cup on the left, it still tested positive for cyanide and was tampered with... I don't see any reason to drink the left cup with the given information.
Is this a logic game or merely a hypothetical? If it's a logic game either it is really simple or I am missing something - however, I wouldn't say I'm missing something if you say "he put something in it while you weren't looking" or "the testing kit was broken!" I am curious now.
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
50 people watched him put pill in left cup, do positive cyanide test on it, do nothing to the right cup but fill it with water, and they all drink the from the left cup? Again, is there any reason why you wouldn't choose a cup which you saw was only filled with water over one that some guy put a pill in, even without the cyanide test? I feel like you are missing part of your hypothetical.
I would first ask all those people why the fuck they would drink from the left glass. If they really are close friends and had a reason to do so, they would tell me.
Because you can be paranoia at multiple levels here, nothing one would think of would be waterproof. If there really is no way to tell if your friends are okay, it doesnt matter which cup you drink. Any further estimation would be based on unknown parameters. Though in practice, i'd probably be too stressed out to think straight, not believe my own eyes anymore, and drink the poisoned glass.
I think it's more interesting when you don't know anything (pills put in glasses or not etc) and just have to randomly choose one of two glasses, knowing all your friends chose one particular glass and that only one glass (unknown to you or your friends) is poisonous. Would you go along and all live or all die? Or would you take the risk to die or live alone?
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
50 people watched him put pill in left cup, do positive cyanide test on it, do nothing to the right cup but fill it with water, and they all drink the from the left cup? Again, is there any reason why you wouldn't choose a cup which you saw was only filled with water over one that some guy put a pill in, even without the cyanide test? I feel like you are missing part of your hypothetical.
Why would the 50 people drink from the left cup, if not for the fact that they think something that you aren't thinking about?
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
50 people watched him put pill in left cup, do positive cyanide test on it, do nothing to the right cup but fill it with water, and they all drink the from the left cup? Again, is there any reason why you wouldn't choose a cup which you saw was only filled with water over one that some guy put a pill in, even without the cyanide test? I feel like you are missing part of your hypothetical.
Why would the 50 people drink from the left cup, if not for the fact that they think something that you aren't thinking about?
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
50 people watched him put pill in left cup, do positive cyanide test on it, do nothing to the right cup but fill it with water, and they all drink the from the left cup? Again, is there any reason why you wouldn't choose a cup which you saw was only filled with water over one that some guy put a pill in, even without the cyanide test? I feel like you are missing part of your hypothetical.
Why would the 50 people drink from the left cup, if not for the fact that they think something that you aren't thinking about?
Like suicidal thoughts?
What are the chances that those 50 people all have suicidal thoughts, relative to the chance that they know something you don't, even though what you saw was really obvious?
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
50 people watched him put pill in left cup, do positive cyanide test on it, do nothing to the right cup but fill it with water, and they all drink the from the left cup? Again, is there any reason why you wouldn't choose a cup which you saw was only filled with water over one that some guy put a pill in, even without the cyanide test? I feel like you are missing part of your hypothetical.
Why would the 50 people drink from the left cup, if not for the fact that they think something that you aren't thinking about?
Basically the only relevant details are that one cup contains tap water, the other has the same tap water plus an unknown pill. There's really no question unless there's some hidden "haha gotcha" secret. Pretty sure you forgot or messed up some detail of the scenario that would have made it an interesting choice.
On February 05 2014 11:37 Mothra wrote: This doesn't make sense to me... are you saying you're the only one that saw the pill go in and the cyanide test? If the 50 people drank from the cyanide cup shouldn't they be dropping dead? Why did all 50 drink from the left cup and why are they asking you to drink from it? I don't see any reason why you couldn't just drink from the right cup and live.
You saw all 50 people watching the same thing you did. You don't have enough time to see whether the 50 will drop dead or not- let's assume cyanide takes an hour to show effect, or something. And it's hypothetical, so you're confusion about the circumstances should be taken into account in your answer.
50 people watched him put pill in left cup, do positive cyanide test on it, do nothing to the right cup but fill it with water, and they all drink the from the left cup? Again, is there any reason why you wouldn't choose a cup which you saw was only filled with water over one that some guy put a pill in, even without the cyanide test? I feel like you are missing part of your hypothetical.
Why would the 50 people drink from the left cup, if not for the fact that they think something that you aren't thinking about?
Basically the only relevant details are that one cup contains tap water, the other has the same tap water plus an unknown pill. There's really no question unless there's some hidden "haha gotcha" secret. Pretty sure you forgot or messed up some detail of the scenario that would have made it an interesting choice.
Maybe there is some hidden "haha gotcha" secret. And you have some reason to believe that that exists, because that would possibly be the simplest explanation as to why the 50 people drank from the left.
On February 05 2014 14:37 lichter wrote: seriously, throwing both glasses at the crazy dude is the best option
lol, I like how you came back to reiterate your point
Well, it is to prove the point that the hypothetical situation you present is so open ended with unknown variables and loose ends that it is possible to really do anything you want without arriving at a 'true' right answer. So far you, as the presenter of the premise, have added information slowly every time someone suggests a solution.
Ask the 50 dudes why they drank it? Nope they aren't telling you for some reason.
Wait for the 50 dudes to die or react? Nope you have to drink immediately for some reason.
Confirm the veracity of the cyanide pill or cyanide test? Nope can't do that either for some reason.
When a premise is not water tight there is no answer.
So just throw the poison at his face because the guy is obvs a jerk.
Given that this man has done nothing to indicate that he is capable of fulfilling his thread to kill all of us, I'd probably say to skip drinking out of either cup and call 911. (although, knowing myself and my friends, if that situation actually arose, I would probably think it some elaborate practical joke.)
You guys are not reading the situations properly. You're not supposed to solve this, you're supposed to say what you would do, and it tells you about your character. You guys have hung out in the mathematical quiz thread too much, looking for a definite answer when there can't be one.
Personally, I would drink from the right glass. I would have no reason to believe my friends know something I don't, and I trust my own perception. Unless I somehow fucked up when the pill was inserted, I should be fine. Sad that 50 of my friends are dying, but otherwise fine.
Unless, of course, the 50 people drinking from the left glass left it empty, that would be a good time to "drink" from it.
(Though, the OP does say he want to be proven definitely "correct", which is dumb since the scenario has no "correct" solution, it's all lateral thinking.)
On February 05 2014 13:03 DarkPlasmaBall wrote: The answer is: It doesn't matter because you've spent years building up a resistance to iocane powder cyanide.
This is what I was thinking. Not all 50 of your friends need be suicidal; only one of them does, or has to be acting irrationally on account of the stress of the situation. Let's say either one of these is true, and the first friend drinks from the left glass, which tested positive for cyanide.
Any rational person would assume that the first friend would be doomed to death by poison. Why, then, do the other 49 also drink from the same poisonous glass? Is it perhaps that they cannot bear the thought of living without the first friend, as the second drinker is the first's spouse or significant other, and the third is the second's mistress, and the fourth is the third's stalker, and the fifth is the fourth's mother, and the sixth is the fifth's husband, and so on?
Naturally, if one is aware that the cyanide's effects will not be made clear until after the drink has been chosen, they should choose the right glass. Drinking the water that tested positive for cyanide just because everyone else did it, and appears to be fine seconds later, while the poison could in fact be coursing through their veins, ticking down the time they have remaining, is suicidal.
If they all know something you don't, but you can't ask them whether they do, then it is still in your best interest to drink the glass that tested negative, because it is impossible to know whether they have been acting rationally, which the first drinker clearly hasn't, and thereby reasonably come upon the conclusion that the glass that tested positive is safe to drink.
How do we know what the test results were, anyway? Are we certain that one result is different from the other? You said the cyanide takes time to have an effect, yet there is one positive result and one negative. Does this mean that the cyanide test reacts immediately, and people do not?
Well, there is either a psychopath or a highly functioning sociopath standing in your kitchen, threatening to kill you and all your friends. If he is the former, logic wont help you and if he's the latter, you are probably not smart enough to beat him in his own game. Thus, we arrrive at the only sensible solution: use force and numbers to overwhelm him. end of story.
edit: since the scenario is so vague that there can't be a right answer, there is no need to accept that you have to drink from on of the cups.
If you dilute it in enough water you can probably get away with a sip, although because you get the last part of the glass, I assume most of it has stuck to the bottom. In that case, all of you charge him, he can't stop all 50 of you.
I think the OP's question was not put across perfectly, as there are some ambiguities, but basically the gist I get is would you make a choice that seems logical to you, or a choice that seems illogical to you, but everyone else is making? Would you trust your own judgement, or the judgement of the majority?
In this case, assuming none of them have ever interacted with the man before and have no knowledge that this test was going to happen, then the right cup would be the logical choice.
However, seeing that none of them are acting hysterical or showing any human reactions to fear at the presence of the psychopath giving such a test, and can all calmly make a choice, something is very strange about the situation. Perhaps they do know something about the test.
In conclusion, the best solution would be to take any one of the two cups, empty it in the sink, wash it thoroughly, fill it with normal water, and drink from it, since the test giver only said "we must drink from one of the cups", not that we must specifically drink the liquid he poured in. I win on a technicality kthnxbai.
On February 05 2014 21:07 Pangpootata wrote: I think the OP's question was not put across perfectly, as there are some ambiguities, but basically the gist I get is would you make a choice that seems logical to you, or a choice that seems illogical to you, but everyone else is making? Would you trust your own judgement, or the judgement of the majority?
We are not talking about random people but a group of your friends. If you prefer your own judgement over a consensus of your friends you'd better be sure you have more information than they do. Or chose your friends more carefully.
On February 05 2014 16:24 Tobberoth wrote: You guys are not reading the situations properly. You're not supposed to solve this, you're supposed to say what you would do, and it tells you about your character. You guys have hung out in the mathematical quiz thread too much, looking for a definite answer when there can't be one.
I disagree, there is a definite correct answer and it depends on details not elaborated in the OP. If two people make different sets of assumptions they can reach different answers even if both of them reasoned correctly. Worse they might argue about it not realizing what they actually disagree on. Thinking that the other person's answer reveals something about their character when it's actually based on differring assumption is a pretty big blunder.
I think some assumptions are interesting enough where it makes sense to explore them in detail. E.g, there's absolutely no way to trick the challenge, there's no way to get additional information, both you and your friends seem to be in full control of your mental faculties and actions, the test is probably right, the pill is probably cyanide, drinking the poisonned water probably kills you, drinking the clear one probably doesn't, you and your friends probably prefer staying alive (both as a group, but also individually, if all of your friends do die).
The funny thing is that all of these assumptions can't be correct with a 100% probability. If your friends want to stay alive and they know the drink in the left cup will kill them and the other not they would not be drinking from it. So one of these assumptions (or actually your observation of what happened) is incorrect.
I guess if it was me, I would just drink the cup that everyone else drank. It really doesn't matter because everyone has a 50% chance of drinking the poison. However, that doesn't improve the probability that you won't drink the poison either, your chance is still 50 50.
I thin it would be better if there were 49 people and 24 of them drank out of the right cup, and 24 of them drank out of the left cup, instead of all 50 drinking out of 1 cup as well.
ANd whatever answers you recieve will all be flawed. The question itself was logically flawed and cannot have a logical answer based on flawed logic.
On February 05 2014 16:24 Tobberoth wrote: You guys are not reading the situations properly. You're not supposed to solve this, you're supposed to say what you would do, and it tells you about your character. You guys have hung out in the mathematical quiz thread too much, looking for a definite answer when there can't be one.
I disagree, there is a definite correct answer and it depends on details not elaborated in the OP. If two people make different sets of assumptions they can reach different answers even if both of them reasoned correctly. Worse they might argue about it not realizing what they actually disagree on. Thinking that the other person's answer reveals something about their character when it's actually based on differring assumption is a pretty big blunder.
I think some assumptions are interesting enough where it makes sense to explore them in detail. E.g, there's absolutely no way to trick the challenge, there's no way to get additional information, both you and your friends seem to be in full control of your mental faculties and actions, the test is probably right, the pill is probably cyanide, drinking the poisonned water probably kills you, drinking the clear one probably doesn't, you and your friends probably prefer staying alive (both as a group, but also individually, if all of your friends do die).
The funny thing is that all of these assumptions can't be correct with a 100% probability. If your friends want to stay alive and they know the drink in the left cup will kill them and the other not they would not be drinking from it. So one of these assumptions (or actually your observation of what happened) is incorrect.
It was basically this type of analysis that I was hoping for, and where my friends and I disagreed about what was the most logical course of action to take. Which observation do you "ignore"?
Yes, I know you can "Not drink either", or "Wait a while to see if the people will die", or "Punch the guy in the face and run". Ignore those- they're not relevant (and the whole thing is hypothetical anyways). You have only 2 possible courses of action- drink from the left, or drink from the right. It doesn't matter why, but those are your only options. Which one do you do?
On February 06 2014 00:53 HwangjaeTerran wrote: I would get suspicious when 50 people claiming to be my friends show up. So I'd be gone before the cyanide guy gets there.
lol happy 5k! I'm happy I can be here to share this moment with you.
Pretty sure i'd pick the one everyone else drank. My reasoning would be that i assume: a) 50 people are most likely more clever then 1. b) they all seem to stay really calm. If they were afraid of dying they probably wouldn't. c) if i dont understand anything here and its a 50/50 shot, then i'd prefer to live in world with my friends contrary to a world where about everyone i like is dead.
1. either everyone around u knows something u dont, or saw something u didnt etc. and are drinking from that cup for a reason
or
2. everyone is wrong and u go out with them (what an even more miserable world it wld be after losing ur 50 best frends)
or
3. even assuming that the other cup isnt poisoned, can u imagine what life would be like after that, 50 of your closest friends/family all die, in your house, drinking from your cups, and you tell everyone "no its ok, this mysterious guy came in and made us drink from one of the two cups, and i just happened to be the only one who didnt drink the poison"
or
4. the fastest way to get out of the game is to kill yourself
On February 05 2014 16:24 Tobberoth wrote: You guys are not reading the situations properly. You're not supposed to solve this, you're supposed to say what you would do, and it tells you about your character. You guys have hung out in the mathematical quiz thread too much, looking for a definite answer when there can't be one.
I disagree, there is a definite correct answer and it depends on details not elaborated in the OP. If two people make different sets of assumptions they can reach different answers even if both of them reasoned correctly. Worse they might argue about it not realizing what they actually disagree on. Thinking that the other person's answer reveals something about their character when it's actually based on differring assumption is a pretty big blunder.
I think some assumptions are interesting enough where it makes sense to explore them in detail. E.g, there's absolutely no way to trick the challenge, there's no way to get additional information, both you and your friends seem to be in full control of your mental faculties and actions, the test is probably right, the pill is probably cyanide, drinking the poisonned water probably kills you, drinking the clear one probably doesn't, you and your friends probably prefer staying alive (both as a group, but also individually, if all of your friends do die).
The funny thing is that all of these assumptions can't be correct with a 100% probability. If your friends want to stay alive and they know the drink in the left cup will kill them and the other not they would not be drinking from it. So one of these assumptions (or actually your observation of what happened) is incorrect.
Which means there is no definite correct answer. "One of these assumptions is wrong". Right. But it could be any of them, and there's no way to find out why from the OP, thus there's no correct answer to the question, you have to make up your own situation. You make up a reason why your friends drank the poison, and depending on what reason you decided, either the left or right cup is the correct one to drink.
On February 05 2014 16:24 Tobberoth wrote: You guys are not reading the situations properly. You're not supposed to solve this, you're supposed to say what you would do, and it tells you about your character. You guys have hung out in the mathematical quiz thread too much, looking for a definite answer when there can't be one.
I disagree, there is a definite correct answer and it depends on details not elaborated in the OP. If two people make different sets of assumptions they can reach different answers even if both of them reasoned correctly. Worse they might argue about it not realizing what they actually disagree on. Thinking that the other person's answer reveals something about their character when it's actually based on differring assumption is a pretty big blunder.
I think some assumptions are interesting enough where it makes sense to explore them in detail. E.g, there's absolutely no way to trick the challenge, there's no way to get additional information, both you and your friends seem to be in full control of your mental faculties and actions, the test is probably right, the pill is probably cyanide, drinking the poisonned water probably kills you, drinking the clear one probably doesn't, you and your friends probably prefer staying alive (both as a group, but also individually, if all of your friends do die).
The funny thing is that all of these assumptions can't be correct with a 100% probability. If your friends want to stay alive and they know the drink in the left cup will kill them and the other not they would not be drinking from it. So one of these assumptions (or actually your observation of what happened) is incorrect.
Which means there is no definite correct answer. "One of these assumptions is wrong". Right. But it could be any of them, and there's no way to find out why from the OP, thus there's no correct answer to the question, you have to make up your own situation. You make up a reason why your friends drank the poison, and depending on what reason you decided, either the left or right cup is the correct one to drink.
I guess that's true. There is no one correct answer but there is a correct answer for any particular set of assumptions.
On February 05 2014 16:24 Tobberoth wrote: You guys are not reading the situations properly. You're not supposed to solve this, you're supposed to say what you would do, and it tells you about your character. You guys have hung out in the mathematical quiz thread too much, looking for a definite answer when there can't be one.
I disagree, there is a definite correct answer and it depends on details not elaborated in the OP. If two people make different sets of assumptions they can reach different answers even if both of them reasoned correctly. Worse they might argue about it not realizing what they actually disagree on. Thinking that the other person's answer reveals something about their character when it's actually based on differring assumption is a pretty big blunder.
I think some assumptions are interesting enough where it makes sense to explore them in detail. E.g, there's absolutely no way to trick the challenge, there's no way to get additional information, both you and your friends seem to be in full control of your mental faculties and actions, the test is probably right, the pill is probably cyanide, drinking the poisonned water probably kills you, drinking the clear one probably doesn't, you and your friends probably prefer staying alive (both as a group, but also individually, if all of your friends do die).
The funny thing is that all of these assumptions can't be correct with a 100% probability. If your friends want to stay alive and they know the drink in the left cup will kill them and the other not they would not be drinking from it. So one of these assumptions (or actually your observation of what happened) is incorrect.
Which means there is no definite correct answer. "One of these assumptions is wrong". Right. But it could be any of them, and there's no way to find out why from the OP, thus there's no correct answer to the question, you have to make up your own situation. You make up a reason why your friends drank the poison, and depending on what reason you decided, either the left or right cup is the correct one to drink.
But that's the point! You have to guess what reason your friends drank the poison. But it's not an arbitrary guess- you have to calculate the chance of your friends all drinking what you would have sword to be cyanide, relative to the chance that what you are mistaken about what's going on, somehow. I agree that once you make a guess about whether or not what they did makes sense, you are done, but what will that guess be? Will you assume they are acting logically, and you don't know something, or that what you think you know is enough to convince you that they are not acting logically?
You guys HAVE all been spending too much time in the mathamatics thread. This is a question about how much you trust your own perception vs how much you trust other people. You are in a situation which does not make sense, you have the premise, you have the assumptions and yet the conclussion is a complete contradiction. So you have to try and guess where the mistake is.
I have a few REALLY really smart friends. I'm sure almost every person here knows someone who could run circles around them intellectually. Yet they are making an unexpected choice so you have to ask yourself "do I really trust their judgement?", if the answer is yes then they likely have knowledge about the situation you don't. Or maybe YOU are mistaken about which glass is poisened. You thought you saw the left glass get poisoned but can you really be sure of that? I think it's best not to unquestionably trust your own perception, especially in stressful circumstances as it has been proved time and time again to be unreliable.
Personally I think I would chose the right glass. But I had to think about it for a while and can understand someone who might chose the left glass.
We'll call the origional scenario scenario A. Let me propose a slightly different scenario: SCENARIO B: "the poison is poured into the glass in front of everyone but then everyone EXCEPT me is blindfolded. They each take a turn to take off their blindfold and drink from one of the glasses. If each person drinks from the left glass then I too will drink from the left glass. I don't care that I THINK I saw the poison go in that one I could be wrong about that. It's not like I've never made a mistake in a stressful situation before. There is no way to verify and double check which is poisoned.
A unanimous agreement between 50 seperate observations outways a single observation (yours). If 50 witnesses to a crime say the car was red and one guy says it was blue what are you going to believe? Doesn't matter how convinced that one guy is."
There is a big difference between scenario A and B. Scenario B has 50 independant observations all coming to the same conclussion. In the origional scenario, scenario A, each descission is not made in a vacuum. Each person who takes a drink has observed the others taking a drink. Say the first person was not paying attention at the correct time, made a mistake due to stress and confusion, maybe they were looking for an exit, whatever. All it would take is for the first person to mess it up and then that sets the ball rolling for group think. The more people drink from the left glass the more pressure is put on the next person. People question their own judgement and then retroactively change their mind about which glass they saw poisoned. It's like with witnesses to a crime, it is vitally important that witnesses DO NOT talk to each other until they have given a full testimony in private. Otherwise they will subconsiously change their perceptions of what happened to be in line with other peoples testimony leading to details being supressed and potentially false information.
Scenario B is 1 observation vs 50. I can't overcome that huge disparity, I must be the crazy person in the group. I'm drinking the left cup.
In scenario A it is my 1 observation vs only a few observations and a whole mess of group psychology. As the saying goes, "a person is smart and capable, but a group of people is stupid and crazy". I'm drinking the right cup.