“Three logicians walk into a bar…” (bar joke)
“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” A popular logic joke is:
The bartender says: “Would any of you guys like a drink?”
The first logician says: “I don’t know.”
The second logician says: “I don’t know.”
The third logician says: “No.”
The joke has been cited in print since at least August 2011; in other versions, the third logician says “yes.” The joke is essentially the same as the one about the logicians and coffee that Will Shortz told on NPR on August 2009.
NPR
It’s All About The Wordplay
Updated August 10, 2009 3:11 PM ET
Published August 9, 2009 2:35 AM ET
WILL SHORTZ
(...)
A waitress walks up to a breakfast table with five logicians and asks, “Does everyone here want coffee?”
The first logician says, “I don’t know.”
The second logician says, “I don’t know.”
The third logician says, “I don’t know.”
The fourth logician says, “I don’t know.”
And the fifth logician says, “No.”
Who did the waitress bring coffee to — and why?
The Big Questions
Friday Humor
Published by Steve Landsburg on August 5, 2011
Three logicians walk into a bar.
The bartender says: “Would any of you guys like a drink?”
The first logician says: “I don’t know.”
The second logician says: “I don’t know.”
The third logician says: “No.”
Hat tip to Adam Merberg, who isn’t sure of the source.
COMMENTS
Colin
August 6, 2011 at 12:21 pm
That’s funny, just three or four days ago I heard this:
Three logicians are sitting in a restaurant. The waitress asks “is everyone having coffee?”
The first logician says, “I don’t know.”
The second logician says, “I don’t know.”
The third logician says, “Yes.”
Schneier on Security
bolson • August 31, 2011 9:30 AM
Three logicians walk into a bar. The bartender asks, “Would any of you like a drink?” The first logician says, “I don’t know.” The second logician says, “I don’t know.” The third logician says, “No.”
Spiked Math Comics
Three logicians walk into a bar - September 22, 2011
Not sure who made this joke up… but it’s a good one!!
Language Log
Three logicians walk into a bar
September 24, 2011 @ 11:28 pm · Filed by Julie Sedivy
(...)
This time, the failure is not in domain restriction of course, but in failing to acknowledge the intended communicative force of the question. Instead of taking the server’s question to be something akin to “Addressing myself to each of you, what do you want from the bar?” the logicians interpret it literally and uncooperatively as a yes/no question—the answer to which only the last of them is in a position to deduce based on the answers given by the other two. By the way, if you’ve ever gone to a bar with a logician, you know that they are likely to engage in just this sort of behavior as a form of tickling themselves.
(I found this comic thanks to Peter Lasersohn; it comes from the folks at Spiked Math Comics.)
Google Groups: Fiji-users
Fiji OSX folder icon
Johannes Schindelin
9/30/11
(...)
Three logicians walk into a bar.
Bar tender: So, beer for all of you?
Logician #1: I don’t know.
Logician #2: I don’t know.
Logician #3: Yes.
Clear Language, Clear Mind
Three logicians walk into a bar: a formal explanation
NOVEMBER 1, 2011 BY EMIL O. W. KIRKEGAARD
(...)
Now, c has all the information he needs to answer either “Yes” or “No”. Obviously, if any of the previous answers are “No”, then he should also answer “No” or simply not answer. If both earlier answers are “I don’t know”, he can infer that both a and b want beer. He also knows his own state. If he does not want beer, he will answer “No”. If he does, he can infer that E is true, and thus answer “Yes”.
Google Groups: sci.math
Maximisation problem
Paul
7/26/13
Let n be a fixed integer > 1.
n logicians walk into a bar. The barwoman says “Do all of you want a beer?” The first logician says “I don’t know.” The second logician says “I don’t know.” ... The n-1st logician says “I don’t know.” The nth logician says “Yes please.” Which value of n maximises the humorousness of the joke? I read it with n = 3 but n = 2 also illustrates the principle.
Paul Epstein
BhaviniOnline.com
posted on MARCH 14, 2014 by BHAVINI
Explanations To 28 Jokes Only Smart People Can Understand
(...)
3. Three logicians walk into a bar. The bartender asks, “Do all of you want a drink?”
The first logician says “I don’t know.”
The second logician says “I don’t know.”
The third logician says “Yes!”
Why it’s funny: A Logician would answer any question asked to him in yes, no or I don’t know because of insufficient data with his logic. In this joke the first 2 logicians don’t know if the third one will have it, so they reply I don’t know. As in if any one of them would not have wanted to drink they would reply in No but since they replied I don’t know, it means they want to but they don’t know about the others. The third one knows from their replies that the first 2 want to and he also wants to so he replies YES.
Nerdy Jokes
April 19, 2014
Logical Laffs
By LC
Three logicians walk into a pub. The bartender asks “Do all of you want a drink?”
The first logician says “I don’t know.”
The second logician says “I don’t know.”
The third logician says “Yes!”
Google Books
The Big Think Book:
Discover Philosophy Through 99 Perplexing Problems
By Peter Cave
London: Oneworld Publications
2015
Pg. ?:
Three logicians walk into a bar: ‘Do all of you want a drink?’ asks the barmaid. ‘I don’t know,’ replies the first logician. ‘I don’t know,’ replies the second. The third simply says, ‘Yes.’ The third rightly reasons that Logician One and Logician Two must want a drink, but do not know if he wants a drink; hence neither One nor Two knows if all three want a drink—whereas he now knows the truth about ‘all three’, given he knows that he is in need of the refreshment.
Stack Exchange
3 Logicians Walk Into a Bar
Bob
asked Apr 19, 2015 at 11:06
Three logicians walk into a bar. The barman says, ‘Does everybody want a drink?’
The first logician says, ‘I don’t know.’
The second logician says, ‘I don’t know.’
What does the third logician say?
Please provide a clear explanation of why each of the logicians reply in the way they do.