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David Aronchick › Comments
Four logicians are having breakfast. Waitress asks -- Will you all be having coffee? The first logician says "I don't know." Second says "I don't know." Third says "I don't know." Fourth says "No." The waitress returns with their coffees. Who gets coffee?
Ramana Rao, Flemming Funch, Drew Robinson and 50 other people liked this
I don't know :)
- Ahsan Ali aka. Slick
from IM
The puzzle actually has a solution.
- Dave Winer
1, 2, and 3.
- Tudor Bosman
The first three. Anyone who wasn't having coffee could safely say "no". If anyone before the fourth said no, it would be indeterminate.
- Matt Mastracci
No one gets coffee. 4 answered for all of them.
- Ahsan Ali aka. Slick
The first three were unsure, the forth one was the only one having coffee, he said no because he is the only one to have coffee.
- Moobie
Well, they're *not* at the Nonlinear Cafe, that much I can deduce :)
- Micah Wittman
Tudor and Matt got it. The question wasn't "Who wants coffee?"
- Dave Winer
Fourth knows she doesn't want coffee, so she says no, they will not ALL be having coffee.
- Arek Dreyer
FF is good for puzzles. If you don't want to see the answer you don't have to. :-)
- Dave Winer
But what about upside down coffee cups?
- Arek Dreyer
What if the question was "Does anyone want coffee?"
- Arek Dreyer
If the question was "Does anyone want coffee?" then we wouldn't be here talking about this now. :-D
- Moobie
Arek, the answer would then be "nobody gets coffee".
- Matt Mastracci
maybe, maybe, maybe, yes. (Arek, these would have to be the answers, for it to make sense).
- Panayotis Vryonis
The first three are ordering coffee, but don't know if the rest are. The last is not, and can safely say "No." Any other answer doesn't work, AFAICT.
- Tanath
Why is it ruled out that the fourth gets coffee? He could be merely mistaken. Him not getting coffee is not a warranted true belief until he, in fact, doesn't get coffee.
- Mark Trapp
the first three get coffee. the first three all would have been able to say "no" if they were not having coffee since that would mean they were not ALL having coffee. But because they were having coffee, and didn't know what the remaining people were going to answer, they could only say "I don't know".
- David Aronchick
All four get coffee because the waitress was confused by their indirect method of answering her question so when she returned she simply left the pot on the table.
- Garin Kilpatrick
Coffee for all! :)
- Garin Kilpatrick
She returns with 3 coffees for the guys who said I don't Know.
- Louis Rossouw
Where's the credit to Will Shortz and Merl Reagle??? http://www.npr.org/templat... btw - I like @DavidAronchick's answer!
- Mark Chance
Excellent. I'll ask that the first person I'll be interviewing for a job :-)
- Till
@Till: "Will you be having coffee?" "-Yes" "-You are hired!"
- Jemm
Friendfeed works well for this. With the answer in the comments it is not immediately visible and gives the reader an opportunity to think before seeing the solution.
- Scott Magoon
Apparently this was on NPR yesterday. I heard it from a friend who (I guess) must have heard it there.
- Dave Winer
Reminds me of the Amtrak announcement at limited stations, "All doors will not open."
- Jim Spath
We all know the answer to who gets coffee. It is 42. But who got the decaf? Did they use milk, non-dairy creamer, sugar, artificial sweetener...? That is the true test, the real conundrum. Answer that please.
- Richard
1,2,3 couldn't say yes due to order but didn't say no so they each wanted one
- Mark Essel
from iPhone
No-one knows if they will all be having coffee or not until the fourth says 'no' because he surely knows the answer to her question ie that he does not want any. Waitress and other three now know they will not 'all' be having coffee so she brings enough for three. They give her a large tip.
- Denise Danks
Should I try to answer this question before or after I have coffee this morning??
- Jannifer @wordsforliving
as the question was "will you *ALL* want coffee" , then there must be three OR LESS coffees delivered, as the fourth person was definitely not having coffee, being the only one who KNEW they wouldn't ALL be having coffee
- kosso
The first three guys get coffee. If any of them didn't want coffee, then the answer for them would have been "no".
- Otto
@Samuel Wood: I would disagree. The first three HAVE to say 'I dont know' as they have no idea if they will ALL get coffee. It doesn't mean they all chose to have coffee at all.
- kosso
I'll have a coke and a muffin to go
- Johnny Worthington
@kosso: If the person themselves did not want coffee, then they would instantly know the answer is no, they all did not want coffee, because that person didn't want coffee. The only way somebody can answer "I don't know" is a) he wants coffee and b) he's not sure if the other three do or don't want coffee.
- Otto
1, 2 & 3 were having coffee, since their answer was YES, but they could not confirm if they would ALL be having coffee. The fourth one was the only one who could really answer the question, after hearing everyone elses' answer. He did not want any coffee, so he replied NO. (i.e.: whoever did not want coffee would have been in a position to give a negative answer. The fact that it was the last one is logiacal, but tricky) 3coffees please
- constantinos alexacos
I think any of the earlier ones could have said no if they didn't want coffee, but then the riddle would be unanswerable, yes? Because the later responders would have to say no whether they wanted coffee or not.
- Jandy, ConcertMaven of FF
from iPhone
Exactly, Jandy.
- Brome
I think that was an extremely patient waitress.
- Ian Mulvany
Yes, the puzzle should have mentioned that not only is the waitress patient but she was a logician as well.
- Dave Winer
first three. i'm with louis.
- Marg Uerite
Only the person who gave the 'right' answer gets coffee, but he said no.
- Bob Boynton
The answer is me. Because answering logic puzzles before I've had my coffee is too damned hard.
- Steven Perez
all of them get coffee - excpet the last bugger
- Peter Dawson
1,2 & 3 get coffee, as answering "no" means "not all 4 of us": the last is the only one who can see the whole picture, so the first three cannot say "yes" - they lack information. Starting with the first: if he wants coffee, he just knows that 1 on 4 will be served and his answer is "I don't know" (he doesn't know about the other 3). If he doesn't want coffee, then he knows for sure...
more...
- Fabio
TwitSnaps jumps into competitive Twitter photo sharing space - http://scobleizer.com/2009...
Svartling, Kol Tregaskes, Jannifer @wordsforliving and 20 other people liked this
What the hell is wrong with the word Tweet? I'm running out of pre-printed legal letters.
- Leo Laporte
Twitpic should definitely implement this zoom feature!
- Kris
Haha, so true! @leo
- Sam Houston
Leo, ask Biz - http://blog.twitter.com/2009...
- Mike White
♥
- meg colombo
Leo is the Twit master, don't you know. How about smile at the BirdySnap instead
- Eran Even-Kesef
Or maybe use something original and more generic, like "social", or "stream", or "micro"
- Jesse Stay
I can't wait for Trademark wars to ensue and when Leo and Iain from TweetDeck all go after Twitter for infringement of *their* trademarks :-) Then what will happen to all these "Twit" and "Tweet" apps when Twitter has to change their name?
- Jesse Stay
Leo: I think a lot of these guys are going to run into trademark issues. If not with you, then Twitter itself. I'll say more in a post later today.
- Robert Scoble
we can still say "twat". right?
- Mike White
Robert, I think TweetDeck has a trademark claim as well - they were using "Tweet" before even Twitter
- Jesse Stay
@Leo, you just can't catch a break... :-(
- Joey Gibson
I'm surprised "twit" is defendable as a trademark in the context. IANAL.
- David Aronchick
Oh, now I get it: Twitter's new business model is suing developers who are using twit or tweet in their apps. Great!
- Kris
I don't want my stuff EVERYWHERE! I'm sticking with Flickr and Youtube. It seems to be working fine for me with my new iPhone.
- Hummie
Domains are getting so hard to find... We use these words to help describe our new-fangled services, we need them! ;) Using tweet/twitter/etc lets a user know instantly that it's associated with Twitter, something that I think they need to know.
- Colin
Colin, I think it's a mistake to just limit your app to Twitter - leave room to expand in the future. Just my $.02...
- Jesse Stay
I think there are advantages and disadvantages to focusing on a service, and focusing on connectivity between many services.
- Colin
i think flickr is a killer for them, but http://twitvid.com is great for videos
- Gaith
Gaith: Twitvid ripped off twitio, which is why I didn't include them in the list.
- Robert Scoble
How so Scoble?
- Colin
Colin: the founders of Twitvid.io explained to me personally how Twitvid.com ripped off their design, their idea, and is run by a venture backed group of five people. I hate it when that happens.
- Robert Scoble
Lots more on the rip off here: http://www.google.com/search...
- Robert Scoble
Hmph, sucks I guess
- Colin
Colin, advantage or not, you've still got Trademark to deal with (Twitter, TweetDeck, TWiT.tv, etc. all have a responsibility to defend their trademarks, and WILL fight it in court if they're to maintain those trademarks). Not only that, but you risk Twitter themselves changing their name if they get bought by another company, or completely going under. To me naming your company after Twitter (which is what you're doing) is a HUGE risk.
- Jesse Stay
Life can be risky sometimes I guess, I accept it. I enjoy developing on Apple's iPhone, and on Twitter.
- Colin
Afternoon all, so who are we suing?
- Iain Dodsworth
Colin: it's a stupid strategy to use someone else's trademark knowingly. If you get sued the legal bills to SUCCESSFULLY defend it could put you in bankruptcy. And if you are unsuccessful it gets far worse. Pick an original name. It's not THAT hard.
- Robert Scoble
Iain: I wanna meet up next week in London. Wanna get together? (Iain is founder of TweetDeck). Love the iPhone app!
- Robert Scoble
Robert: bugger...that's some amazing timing - I was hoping to catch up with you, I'll be in SF all week. Glad you like the iPhone app, lots of room for improvement but it's only v1.0 and gives an indication what we're up to :)
- Iain Dodsworth
I don't understand how this is an issue. TWiT, Twitter, tweet, etc... Perhaps I'm missing something.
- Jason Hansen
I want my users to know that my applications are for Twitter, that's almost the first thing I want them to know when they read the title.
- Colin
Robert: also sorry to have missed you in NY the other week, things were crazy with 2 product launches
- Iain Dodsworth
Iain: grrr. When do you get here?
- Robert Scoble
try videotweet.com
- Bala Menon
from IM
Iain how long are you in New York for?
- Jesse Stay
Robert: plane lands in SF Tuesday 9pm
- Iain Dodsworth
Iain: can we meet Sunday? in London?
- Robert Scoble
Hey Jesse, I was in NY for the 140conf now back in London
- Iain Dodsworth
Robert: Sunday in London would be somewhat difficult (it's my birthday and have some things going on at home) - BUT I'll be spending the summer in the valley so we can definitely get together then (a few weeks time)
- Iain Dodsworth
Iain if you end up in the New England area (New York, Boston, etc) I'll be there for a whole month starting in a week. Would love to catch up some time.
- Jesse Stay
Iain: OK, let's get together when you're in the valley.
- Robert Scoble
Robert: good - I'll let you know when I'm there...apologies if this is cheeky - but is there a particularly good place to base myself whilst there...Menlo Park, Redwood City, Palo Alto ???
- Iain Dodsworth
Jesse: sounds good - if I get over to the east coast I'll definitely let you know, would be good to meet up
- Iain Dodsworth
Iain: Twitter is in San Francisco. Facebook is in Palo Alto. FriendFeed is in Mountain View. So, depends where you want to spend most of your time and what you can afford to rent. If funds are unlimited, I'd say San Francisco. More to do at night there.
- Robert Scoble
BTW, Facebook explicitly states in their developer terms no app is to include the name "Face" in its name. You'll be banned from their platform if you're caught. I expect Twitter eventually to do the same (although they are very slow at such moves!)
- Jesse Stay
Give them HELL Leo.
- Tendonitis' Bitch
I like MobyPicture :)
- simone brunozzi
Scobleizer, welcome back to FriendFeed, and you're wrong about there being too many photo sharing services: http://friendfeed.com/brlewis... :-)
- Bruce Lewis
@LeoLaporte Didn't you start Twitter anyway? I thought TWIT and Twitter were one in the same lol
- Justin DeMerchant
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