Truth teller vs liar : go to Hell

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Discussion Overview

The discussion revolves around a classic logical puzzle involving two guards, one who always tells the truth and one who always lies, guarding two doors—one leading to Heaven and the other to Hell. Participants explore various strategies for determining which door leads to Heaven by asking a single question to one of the guards. The conversation includes theoretical reasoning, proposed solutions, and playful commentary.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants describe the puzzle and express their enjoyment of it, noting its historical presence in discussions.
  • One proposed solution involves asking a guard what the other would say about the door's destination, suggesting that the answer given would indicate the opposite of the truth.
  • Another participant suggests a variation of the question that aims to clarify the path to Heaven, but questions its validity based on the requirement for a yes/no answer.
  • Some participants humorously suggest alternative, non-logical methods to deal with the guards, such as physical confrontations.
  • There is a discussion about whether the guards need to know each other's identities for the proposed questions to work effectively.
  • One participant raises a concern that the guards might not necessarily know each other, which could complicate the logic of the questions posed.
  • Several participants offer different formulations of questions that could be asked, with varying degrees of agreement on their effectiveness.
  • Some express skepticism about the necessity of the puzzle, suggesting that it may be overly complicated or trivial.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best question to ask or the assumptions underlying the puzzle. Multiple competing views and proposed solutions remain, with some participants questioning the validity of others' approaches.

Contextual Notes

There are unresolved assumptions regarding the guards' knowledge of each other and the requirement for a yes/no question. The discussion reflects varying interpretations of the puzzle's parameters.

  • #31
How about .. "What door are you standing in front of?" The honest guard points to his door, and the liar guard points to the other one.
 
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  • #32
nuby said:
How about .. "What door are you standing in front of?" The honest guard points to his door, and the liar guard points to the other one.

Ok, now you know who the honest guard is.
And so what?

C'mon guys, you should read the first post.
 
  • #33
Rogerio said:
C'mon guys, you should read the first post.

It confused me, as I've heard it before but proposed differently: truth teller guards Heaven, lier guards Hell.

The no correlation between lying ang telling the truth and which door one is guarding does make a lot more sense now I've thought about it, as there is only one answer:

Will the other guard say he is guarding Heaven?

right?

Isn't this in Labyrinth with David Bowie?
 
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  • #34
neu said:
...
right?

Right.
 
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  • #35
kill both guards then open both doors but don't go in until you find out which door is the one you wish to go in (note some people want to go to hell like satanists)
 
  • #36
Would he say that you are lying?
 
  • #37
you ask either guards:
if i ask the other guard which door leads to freedom what door would he say?
they will show you the same door. you go to the other door.
the point is that the liar will point to the door of the tiger and so would the truth teller.
 
  • #38


Sorry to be totally dead-pan about this.
The answer is a Double Negative.
If you ask the Truthful man what the other man will say he will say what the Liar would say.
If you ask the Liar what the Truthful man would say he will say a Lie, ie the opposite of the Truthful man.
The question therefore is: "If I ask the other man what is the gate/door to life/freedom, what will he tell me" - whatever the answer you do the opposite, because both men will tell either a Lie or a Truthful Lie.
The question must be a Double Negative !
 

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