wu :: forums « wu :: forums - BROWN EYES AND RED EYES » Welcome, Guest. Please Login or Register. Feb 15th, 2019, 7:03pm RIDDLES SITE WRITE MATH! Home Help Search Members Login Register
 wu :: forums    riddles    medium (Moderators: SMQ, Icarus, Grimbal, ThudnBlunder, william wu, towr, Eigenray)    BROWN EYES AND RED EYES « Previous topic | Next topic »
 Pages: 1 ... 9 10 11 Reply Notify of replies Send Topic Print
 Author Topic: BROWN EYES AND RED EYES  (Read 66023 times)
riddler358
Junior Member

Posts: 83
 Re: BROWN EYES AND RED EYES   « Reply #250 on: May 10th, 2016, 1:30pm » Quote Modify

on May 10th, 2016, 12:33pm, rmsgrey wrote:
 Can you ever figure out which case you're in?

you can't but you know for sure it's one of just 2 cases N (number of REM you see) or N+1, moreover everyone else is either in same situation as you or in situation N or N-1, for everyone N-2 is impossible and everyone knows that

@towr i need some more time to understand your last post
 IP Logged
towr
wu::riddles Moderator
Uberpuzzler

Some people are average, some are just mean.

Gender:
Posts: 13660
 Re: BROWN EYES AND RED EYES   « Reply #251 on: May 10th, 2016, 10:52pm » Quote Modify

on May 10th, 2016, 1:30pm, riddler358 wrote:
 you can't but [..]
Actually, you can: just wait 2 days. And then you know that 2REM isn't the case, and therefore 3REM is the only remaining option.

Quote:
 for everyone N-2 is impossible and everyone knows that
But not everyone knows that everyone knows that.
Suppose Alex in secret tells Bob something, and Alex tells Charlie the same thing also in secret. Bob doesn't know that Alex told Charlie; Charlie doesn't know Alex told Bob. Everyone knows the secret, but Bob and Charlie do not know that they both know it. So everyone knowing X does not mean everyone knows that everyone knows X.
And that's important to realize in this puzzle.
 IP Logged

Wikipedia, Google, Mathworld, Integer sequence DB
rmsgrey
Uberpuzzler

Gender:
Posts: 2819
 Re: BROWN EYES AND RED EYES   « Reply #252 on: May 11th, 2016, 7:32am » Quote Modify

on May 10th, 2016, 1:30pm, riddler358 wrote:
 you can't but you know for sure it's one of just 2 cases N (number of REM you see) or N+1, moreover everyone else is either in same situation as you or in situation N or N-1, for everyone N-2 is impossible and everyone knows that

If you don't see any red eyes, I assume you can figure out that you're in the 1REM world when the starting announcement is made.

If you see 1 REM, what happens if you're in a 1REM world? If that doesn't happen, can you then conclude that you're in a 2REM world?

If you know what would happen in a 2REM world, and that doesn't happen when you see 2 REMs, can you then conclude that you're in a 3REM world?
 IP Logged
riddler358
Junior Member

Posts: 83
 Re: BROWN EYES AND RED EYES   « Reply #253 on: May 11th, 2016, 2:19pm » Quote Modify

i found some paradox that might seem related
it might be called eubilides' heap

paraphrasing
if someone is fat then guy that weights 1 kilo less is also fat, and if someone is thin then guy that weights 1 kilo more is also thin
monks do official weighting before breakfast
tourist comes and says at least one of you is fat
imagine there are many monks and all possible weights of monks are present there in the monastery
but another tourist comes and says at least one of you is thin
by these assumptions every monk would be fat and thin at the same time

we build up to something comparing one-to-one but don't bother looking at the bigger picture
 IP Logged
towr
wu::riddles Moderator
Uberpuzzler

Some people are average, some are just mean.

Gender:
Posts: 13660
 Re: BROWN EYES AND RED EYES   « Reply #254 on: May 11th, 2016, 10:24pm » Quote Modify

Having red eyes or not is a binary property, and not an ambiguous judgement like fat/slim.
 IP Logged

Wikipedia, Google, Mathworld, Integer sequence DB
rmsgrey
Uberpuzzler

Gender:
Posts: 2819
 Re: BROWN EYES AND RED EYES   « Reply #255 on: May 12th, 2016, 10:09am » Quote Modify

on May 11th, 2016, 10:24pm, towr wrote:
 Having red eyes or not is a binary property, and not an ambiguous judgement like fat/slim.

Yeah, the sorites paradox rests on trying to be precise about something vague - at the ends of the process, you have something that's definitely a heap, or definitely not a heap, but in between you have things that might or might not be heaps - even if you ask the same person about the same ?heap? they might give different answers depending on the context.

With red eyes, either someone has red eyes or not - there are no awkward edge cases, no eyes where some people say they're red and others say they're blue - so there's no sorites-style ambiguity to grab on to.
 IP Logged
 Pages: 1 ... 9 10 11 Reply Notify of replies Send Topic Print

 Forum Jump: ----------------------------- riddles -----------------------------  - easy => medium   - hard   - what am i   - what happened   - microsoft   - cs   - putnam exam (pure math)   - suggestions, help, and FAQ   - general problem-solving / chatting / whatever ----------------------------- general -----------------------------  - guestbook   - truth   - complex analysis   - wanted   - psychology   - chinese « Previous topic | Next topic »