27 replies to this topic

[fitheachsidhe]

'puzzlers' is correct, its a paradox. Too much unchecked stuff on this site.

[rookie1ja]

'puzzlers' is correct, its a paradox. Too much unchecked stuff on this site.

refer to my post #12 and write where exactly I went wrong in my reasoning

[Gambler]

A: B is a lying monkey. I am human.
B: A is telling the truth.


Let me take a shot ...

A speaks.

B responds either with the truth or with a lie so the 2 cases are ...

CASE1: If B is truthful, then A is telling the truth about B being a liar. So it's a conflict.

CASE2: If B is lying, then by saying "A is telling the truth" he's saying A is lying. If A is, in fact, lying, then B is NOT a lying monkey and since he IS a liar, he has to be a lying man. So, B is a lying man.

Since A is now established as a liar, he must also be lying about being human. So, A is a lying monkey.

A is a lying monkey
B is a lying man


Maybe some confusion comes by assuming that if "lying monkey" is a lie, it means he is neither a liar nor a monkey. But that is not correct. In fact, if "lying monkey" is a lie, it could be a "lying man", a "truthful monkey", or a "truthful man".

Clear as mud.

[Atworldsend]

this was really simple...a is a lying monkey and b is aw lying human! great ethics guys.....

[rob31656]

They speak either only the truth or only lies.

A: B is a lying monkey. I am human.
B: A is telling the truth.


You said they speak either ONLY TRUTH or ONLY LIES. That means that they cannot speak some truths and some lies in a statement. You cannot pull apart lying and monkey, the logic does not work that way. If you ever take a math logic class in college, this is very important. Therefore the puzzle is a paradox! You would have to say A: B is lying OR a monkey. I am human. B: A is telling the truth.

Persons A & B
lying = X
Monkey = Y
Human = Z

A says
B = XY does equal BOTH lying AND monkey
A = Z does equal human
B says
A != x does not equal lying
But
B = XY does equal BOTH lying AND monkey
So
A = X does equal lying &
A != Z does not equal human
Then
B != XY does not equal BOTH monkey AND lying
So
A != X does not equal lying

and so on and so on........

[Beomeister]

Island Baal - Back to the Logic Problems
There are people and strange monkeys on this island, and you can not tell who is who (Edit: untill you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Spoiler for Solution

Island Baal - solution
Conjunction used by A is true only if both parts are true. Under the assumption that B is an honest man, then A would be honest too (B says so) and so B would be a liar as A said, which would be a conflict. So B is a liar. And knowing that, B actually said that A is a liar, too. First statement of A is thus a lie and B is not a lying monkey. However, B is lying which means he is not a monkey. B is a lying man. The second statement of A indicates that A is a monkey – so A is a lying monkey.

I believe the real issue with the puzzle is the word "and", which is missing from the conjuctive statement of person A. As written, person A is making two statements. By definition of the puzzle, those statements are either both false, or both true. There is no "AND" between them, so the solution of assuming one part can be true and the other part false does not apply. Add the word "AND", and then the solution is correct.

[ancyril]

A: is a Lying Monkey
B: is a Lying Human

Hence when A says
"B is a lying monkey. I am human."
Both the statements are lies.

And when B says "A is telling the truth."
The statement is again a lie

Reasoning:
A cannot be truthful because if he is , then B's statement would be a contradiction. If he is not truthful, his second statement would also be a lie. Hence he is not human either. Hence he is a lying monkey.

B cannot be truthful either as he says that A is truthful which A is not. He can only be a lying monkey or a lying human.
Since A's statement "B is a Lying monkey" is a lie... B can only be a lying human

[brightcrayon]

they are both lying