CRITICAL THINKING EXERCISE

“THE CHOICE”

DESIGNED BY CHARLES HENDERSON 2005

Imagine that when you die, you find yourself in a

Room with two doors, one leading to paradise; the other to damnation. You can choose which

door to walk through, but the problem is that the doors are unmarked.

Each door has a guard before it. You can ask eachguard one “yes” or “no”

question. One of the guards will answer truthfully; the

other will always lie.Unfortunately, there is

no way of knowing which guard is which.

What question should you ask

one of the guardsto ensure

that you wind up in paradise?

GUARD

PARADISE DAMNATION

GUARD ??

?

?

?

A visual look at the scenario

“According to the Other guard, this

is the way to paradise?”

HERE IS THE QUESTION TO ASK:

The answer you get will always be untrue,

The lying guard will always say the opposite of what

the truthful guard would say..

The truthful guard will truthfully tell you the other guard’s lie.

Because:

So if the guard says the door does not lead to paradise,

you know it does

If the guard says the door does lead to paradise,you know it does not.

LYINGGUARD

TRUEGUARDT

L

=

=

(“According to the other guard, this is the way to paradise?”)

Paradise Damnation

T L

Paradise

T

Damnation

L

Scenario One Scenario Two

Answer

YNN Y

Paradise Paradise Damnation Damnation

T L LT

N

NOTICE THAT THE ANSWER WILL ALWAYS BE “NO”

IF EITHER GUARD STANDS BEFORE THE PARADISE DOOR

N Y Y