3 Logicians Walk Into A Juice Bar

The first two logicians want a drink. We know this because if say, the first logician didn't want a drink, then his answer would be no. But because he does want a drink, and he's unsure if the others do, the first logician he says, "I don't know."

Similarly, the second logician knows that he wants a drink and that the first logician wants a drink, but again he doesn't know if the third logician wants a drink, so he says, "I don't know."

Finally, since we don't know if the 3rd logician wants a drink, his answer could be "Yes" or "No."

"Does everybody want a drink?" is a question that requires all three logicians to want a drink for the answer to be "Yes." If there exists one person who doesn't want a drink then the "everybody" part will be false.

Therefore, if the first or second logician don't want a drink, then they can simply say "no" in response to the question. For each logician, they want to drink, but they don't know what the rest will say so they can't decisively say, "Yes."

Thus, when it's the third logician's turn, he knows that his friends want to drink but he may or may not want a drink for himself. Hence his answer could be yes or no.

Let's name the logicians Alice, Bob and Charles respectively.

Consider Alice. If she does not want a drink, she would know that the answer to the barman's question - "Does EVERYBODY want a drink?" - is "no". But she doesn't know the answer to the question. Therefore, she does want a drink (which makes sense, because she walked into a bar).

Now, using the above logic, Bob knows that Alice wants a drink. If Bob does not want a drink, he would know that the answer to the barman's question is "no". But since he doesn't know the answer, he wants a drink too (again, sensibly).

Charles now knows that Bob and Alice both want drinks, but he may or may not want a drink. If he does want a drink, he would answer "yes" and if he does not want a drink, he would answer "no."

Hence, both "yes" and "no" are possible answers.

(PS: The first answer that crossed my mind was "Ouch!", since the logicians walked into a bar, and that must be rather painful)

(PPS: This reminds me of a classic joke: After hearing that a logician's wife had just given birth, a friend asks: "Is it a boy or a girl?" The logician's reply? "Yes.")

The fact the first two both reply with, 'I don't know', means that both of them want to have a drink, since if either of them didn't then they would instantly know that not everyone wants a drink.

Therefore, if the third person wants a drink he will answer yes, and if he doesn't want a drink he will answer no. Hence we see that both yes and no are possible answers (though if the third man doesn't want a drink one must question why he would enter the bar in the first place ).

The barman asks if EVERYBODY wants a drink.First we need to keep in mind that EVERYBODY includes oneself. Now the first logician says I don't know. Two possibilities: yes or no. Analyzing these two probabilities... if he/she wants a drink, then that is 1/3 vote and we need to wait for the decisions of the other 2 logicians. If he/she doesn't want a drink, then the answer is immediately obvious and there is no point in awaiting the decisions of the other two logicians. So now we can deduce the decisions of the first two logicians (yes, they want drinks). Final decisions depends on the third logician's decision. Without him saying anything, we cannot be sure of what his decision is, and thus the answer is "Both 'Yes' and 'No' are possible answers". Hope that helped!

P.S. Sorry for all those gender assumptions. Irrelevant to the solution, so please don't judge. :)

Screw the first two guy and push them aside, and then order yourself a beer. Their indecision is not your problem

A few things one must decide out of the gate: "they" in the bartenders question does not assume that any character possesses omniscient knowledge of the entire group's desire or lack of desire for a drink (each character only has knowledge of his/her desire). Second, "they" really is referring to the group and is not just a placeholder for a third person singular pro-noun, as is is often the confusing case in English where there is no third person singular gender-neutral pro-noun. So, the bartender's question refers to the groups desire for a drink though each character knows only his/her personal desire. When asked "Does everybody want a drink", the first two characters could very well say 'no' if either of them didn't want a drink since the necessary condition for "everybody wanting a drink" could not be met if just one character doesn't want a drink. However, since the first two characters answer "I don't know", we know that each of the first two character's personal choice must be "yes", which is implied by the contingency of those character's ultimate response upon the decision of the third character. This leaves the third character to decide if if the necessary condition of "everybody wanting a drink" will be met. If the third character desires a drink, his answer will be "yes", 'everybody wants a drink.' If the third character does not want a drink, the necessary condition will not have been met and he could well say "no." With knowledge of the first two character's decisions, we understand that the third character's decision will determine whether the necessary conditions will be met. Thus, the third logician may answer either "yes" or "no."

we don't know if the 3rd guy wants a drink, but the answer is either yes or no, so combining these 2, yes or no are possible answers.

The only suggestion is , just to click randomly on a option , and it turns out to be the correct answer

Diqjal "A sji!" ed lasjter diqjal zi vii eu envii pakaler zi a va eu enva. Zi lh'eneo diqjad "a ensji" mensa qujoen a va fjoen rinsos, parqjoen zi envoeqned fjoen rinsos, diqja enis "a sji: nausjter!", parqjoen eeni lhi chriesos vii fjoen rinsos enis. Zi lho deseo diqjad "a ensji" a parqjoen a va fjoen rinsos ausjter, lha sjime'ehreh, sjimea sjongeyry. Lho chrieseo eu sja ses'ehrehe, qjoen lh'enei desos vii fjoen rinsos, eu laelloeloep, capia fjoen diqjos "a sji": zi va fjoen rinsos diqjal "a sji: ciege!" eu, "a sji, nausjter!", zi a y enva. Etues?

Obviously the first 2 Logicians wants a drink .. Based on the question phrasing $\textbf{"Does everybody want a drink?"}$

$\text{If the 1st one didn't want then the answer would simply be}\textbf{"No"}$ $\text{as he will break the Unity of the group} \textbf{"everybody"} \text{that might want a drink}$ $\text{Same for the 2nd .. meaning the first 2 are not answering only for themselves but for the group}$ Now the 3rd knew what the first 2 wanted if he also wants then he'll say "Yes" and if not he'll say "No"