I was told the answer is door 2.

Steven G

Elite Member
Joined
Dec 30, 2014
Messages
14,362
Suppose you are in a dungeon with two doors. One of the doors has a treasure and the other has a terrible monster. The doors have signs on them. You know the sign on a door either tells the truth or lies.
FIRST DOOR: "Both doors are lying."
SECOND DOOR: "The treasure is in this room."
Where is the treasure?

I claim that you can't tell where the treasure is. Just suppose that the sign on door 1 was correct, Then the sign on door 2 is false and you do not know where the treasure is. Am I correct or am I missing something?
 
Suppose you are in a dungeon with two doors. One of the doors has a treasure and the other has a terrible monster. The doors have signs on them. You know the sign on a door either tells the truth or lies.
FIRST DOOR: "Both doors are lying."
SECOND DOOR: "The treasure is in this room."
Where is the treasure?

I claim that you can't tell where the treasure is. Just suppose that the sign on door 1 was correct, Then the sign on door 2 is false and you do not know where the treasure is. Am I correct or am I missing something?

But if door 1 is telling the truth, then door 1 and door 2 are both lying ...
 
Last edited:
If first sign is true we are getting the "I'm lying" paradox. I'm guessing this means we can eliminate this possibility.
If it's false - one or both signs are true, but first can't be true, so looks like the second is true and the answer is door 2.
 
If first sign is true we are getting the "I'm lying" paradox. I'm guessing this means we can eliminate this possibility.
If it's false - one or both signs are true, but first can't be true, so looks like the second is true and the answer is door 2.

Why "guess"? If the first sign is true then what it says must be correct. But what it says is that it is lying which is not true. The first sign cannot be true. And once we know that is false, it must be the case that at least one sign is true. Since sign one is false, sign two must be true.
 
Top