T Nation

Logic Puzzle

Some of you may have seen this before (albeit, slightly different). Thought it might be fun for some to wrap their heads around.

The statement at the bottom of this post is false.

The statement at the top of this post is true.

that’s the stupidest fucking thing I’ve ever read, jackass


It’s a variation on this:

“I am lying!”

Old Dax

I think it dates back to the Greek Era.

Our philosophy teacher slipped this one in when we taught logic/proof processes.

Damn pot-smokin’ hippies!


Thanks for your contribution to this “pass the time” thread, roadrunner, I appreciate it. Your head musn’t be able to wrap around much, huh?

Old Dax - very good! This is certainly a similar version of the paradox.

I love to think about this little paradox. I always end up in a complicated cycle and give up. I believe they just cancel each other out. The statement’s cannot coexist, I think…but I don’t know that much logic.

If you try to fail, and succeed, which have you done?

You are trapped in a room with two other guys. There are two doors out. One leads to freedom, the other to death. You don’t know which is which. You know that on of the guys always lies and the other always tells the truth. You don’t know which is which. What one question can you ask to ensure you safely exit the room?

Doogie, since one always lies, you can ask any question to which you already know the truthful answer. “What color is my hair?” would work.

Quite simple;-)

You ask guy 1: If I ask the other guy what door leads to freedom, which one will he show me?

Then you exit the other door.

or, “Do you know which door let’s me out?”

Mace, I think you get one question only.
Doogie, there are two questions (that I can think of) that would help.

1: Ask one guy what the other would say, he will then give you the FALSE answer, the guy telling the truth would tell you the other guys false answer. The guy telling lies, of course, would lie. So whoever answers he will give you the false answer, so you do the opposite.

2: Ask either guy “If I ask you tomorrow, which door leads to freedom, what will you tell me?”
You will then receive the correct answer from either.

Old Dax

I like this answer. I think it would work.

ask which door leads to death.

Is this a question?

A Prof og\f mine posted this as an exam. What is the answer that you think he awarded an A to?

"If you try to fail, and succeed, which have you done? "

–>If you try to fail, you must be trying to fail at something. This you can fail at, while simultaneously succeeding at achieving failure.

Hey, Captain Kirk solved the “one lies and one tells the truth and you get one question” thing long ago…

“I shoot the black one!”

-Lt. Weigel

spiderman: Only if this is an answer.