Special K 0 Report post Posted January 4, 2005 I like this little ditty. Not really a brain teaser as much as a paradox, and not really too difficult to see the flaw in reason, but fun to contemplate for a bit. From Wikipedia. (Originally by Raymond Smullyan?) The Unexpected Hanging A judge makes two statements to a condemned prisoner: -You will be hanged at noon one day next week, Monday through Friday. -The choice of day will be a surprise to you, in that you won't know the day of the hanging until the executioner knocks on your cell door at noon that day. The prisoner reflects on these statements, and then smiles. If the hanging were on Friday, then it wouldn't be a surprise in the sense announced. For he would know by Thursday night that he was going to be hanged on Friday, since no hanging had yet occurred and only one day was left. So the hanging can't be on Friday. But then the hanging can't be on Thursday either. If it were, then it wouldn't be a surprise either. For he would know on Wednesday night that he was going to be hanged on Thursday, since no hanging had yet occurred and only two days were left, one of which (Friday) he already knows is impossible. So a Thursday hanging is impossible too. Similar reasoning shows that the hanging can't be on Wednesday, Tuesday or even Monday! He returns to his cell confident in his safety. The next week, the executioner knocks on his door at noon on Wednesday - an utter surprise. Everything the judge said has come true, but where is the flaw in the prisoner's reasoning? Share this post Link to post Share on other sites
Ace309 0 Report post Posted January 4, 2005 No, because "On your heads you have either a black hat or a white hat" doesn't mean there aren't all of one colour. Yes it does, it means there is at least 1 white hat and 1 black hat, the other is either black or white, if they knew it would be too easy. Remember this is a brain teaser so it's not meant to be too easy. Remember what I said in another thread about how you're trying desperately to use ideas you don't understand? Share this post Link to post Share on other sites
Special K 0 Report post Posted January 4, 2005 I think we're all teasing Jason's brain too much. Like every other thread he's ever been in. Jason, next time stick to "brother's and sisters have I none, but this man's father is my father's son." Much easier to memorize. Share this post Link to post Share on other sites
