Skip to main content
Puzzling

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

Required fields*

3
  • 1
    $\begingroup$ "assuming she/he has sufficiently strong reasoning" - this isn't a good assumption. I think the clever part of the story is that most people have heard enough puzzles about perfect logicians to immediately assume this prisoner must also be one, but as I pointed out in my answer we can see the prisoner is definitely not one. The story wouldn't be nearly as clever if the prisoner's reasoning was "this rock spoke to me and told me I wouldn't be executed", but instead gives a proof that is only subtly wrong. $\endgroup$ Commented Sep 6, 2020 at 4:10
  • $\begingroup$ You're right, I had left out the part "Joyfully he retires to his cell confident that the hanging will not occur at all". I was having in mind a version in which he realizes the contradiction. $\endgroup$ Commented Sep 6, 2020 at 5:51
  • $\begingroup$ However, if we start by saying the prisoner can make reasoning mistakes, the whole thing seems to turn towards a mind trick rather than a logic problem. Because the prisoner's reasoning is part of our reasoning (to determine his surprise) and more than this, the prisoner has the same data that we have - we can imagine any of us can be in his shoes. So if he has a shaky logic, we have a shaky logic, and we don't know where it shakes. Anyway, it's a good mind trick. $\endgroup$ Commented Sep 6, 2020 at 12:44