Your Marbles Or Your Life

Aug 22, 1998

RAY: Many years ago a prisoner was condemned to die. He was in his cell, and the warden came to visit him. He said to the prisoner that his odds of dying the next day are 100% (big damn surprise, right?) But the warden wants to increase the prisoner's chances to 50%. The warden gives the prisoner 2 shoeboxes, one with 50 white marbles, and one with 50 black marbles. The warden will come in blindfolded and pick a marble out of one of the boxes. White, he lives. Black, he dies.

The marbles can be arranged in any way. All the marbles must be used in either box. Is there any way to improve his chances above 50%?

RAY: The prisoner's dilemma: The prisoner can improve his chances from 50/50. If he rearranges the marbles, putting 99 marbles in one box and 1 white marble in the other box, his chances are improved.

Get the Car Talk Newsletter