Talk:Puzzles/Logic puzzles/False Execution/Solution

Discussion is open, i myself belive this is correct solution, but i heard other opinions (not like "your whole riddle is stuipd, i don't get it at all!!1~") Divinity 18:47, 17 Jun 2005 (UTC)

If it was determined he'll be executed on tuesday, the prisoner can't deduce that. Because the logic would lead him to think he can't be executed. Therefor he can't know that any day before, which makes the judge's statement true. The statement the judge makes to the prisoner is non-informative, it can't lead the prisoner to know when he will be executed, because believing it leads to inconsistent beliefs (even though the statement is true). -- towr 129.125.102.149 10:32, 28 Jun 2005 (UTC)


 * I agree with towr. The judge's statement does not convey any information to the prisoner. It can be either true or false, and it is impossible for the prisoner to know which. This should be explained in the solution. -- Grahn 23:07, 28 Jun 2005 (UTC)


 * I have now updated the solution to reflect this, but it could definately be written in a better way. I don't have time to improve it further at the moment, but at least it is correct now. Grahn 19:14, 30 Jun 2005 (UTC)


 * 81.195.24.94, whoever you are: as I said before, my explaination might not have been the best, but you are wrong, and I am quite certain of it. I don't wish to start an edit war, but I will nontheless revert your last edit since it is more of an argument than a clarification. I suggest we keep any further debate here on the talk page, until we can agree on the matter. Grahn 18:24, 13 August 2005 (UTC)


 * Copied from the article before revert of 81.195.24.94's edit: "Not true. We're not talking here about what prisoner thinks. You are a god in this puzzle, and if judge says "Tomorrow you will be executed, as was decided earlier", you might want to ask "When did you decide that?". No matter what judge answers you, that makes hist first statment wrong, because if he would choose a day, prisoner would already know that he'd be executed on that day."


 * But we are talking about what the prisoner thinks/knows. The judge tells the prisoner that "you will get to know the day we want you executed during the dinner the day before it". That is, the prisoner will be given information about his execution the day before it will happen. Whether or not the judge was telling the truth when he said this during the verdict, the prisoner cannot know. We as the puzzle-god could, however, have that information and in fact know that the judge was telling the truth during the verdict---that the prisoner will not know the time of his execution until the day before it---without there being any problem, since the prisoner still does not know. The only thing that leads to contradiction is the assumption that the prisoner knows that the judge is telling the truth, which he cannot. But this does not mean that the judge can't still be telling the truth. It only means that the prisoner can't know that he is, if he is. Grahn 18:50, 13 August 2005 (UTC)

Another caveat
The solution assumes that judge and prisoner agree on the interpretation of "next week". There are two definitions of a calendar week in common usage: Sunday-Saturday and Monday-Sunday. At the moment, it assumes a Monday-Sunday week. If Sunday-Saturday is taken to be the definition of a week, the same argument is equally valid, he just has six days to think about it before they might kill him. But if the judge is using one definition and the prisoner is understanding the other, then I can imagine it being a bit more complicated.

I guess I'll have to think about it a bit more when I've time.... -- Smjg 17:52, 6 January 2006 (UTC)

wrong problem
The problem, in its current incarnation, is not correct:

Here is the current problem, stated as follows:

___ On one Sunday morning, a judge came to prison, and said to one man:

"You are sentenced to death. You will be executed in the morning of one of the days of next week. We have already decided the day, but you will get to know the day we want you executed during the dinner the day before it."

Explain why the judge's statement is false.

___

The above defined problem is not correct: imagine they decided on tuesday morning: on sunday, they don't tell anything to the prisonner, so he can't know which of the remaing days will be the one. On monday they tell him "it's tomorrow morning"...

So the judge told him the truth.

The only thing the prisonner can know is that it won't be on the last day of the week!

(Edhel-Dil.)


 * Yes, the current formulation is incorrect; whether or not the judge's statement is true cannot be derived from the facts presented in the puzzle. However, your last statement is also wrong: the prisoner cannot conclude that he won't be executed the last day of the week out of what the judge has said. The judge's statement conveys no information to the prisoner. Assuming that it does leads to contradiction. -- Grahn 22:08, 6 February 2006 (UTC)