there are three prisoners, one of whom was blind. their jailor offered to free them all if any one could succeed in the following game. the jailor produced three white hats and two red hats and, in a...

there are three prisoners, one of whom was blind. their jailor offered to free them all if any one could succeed in the following game. the jailor produced three white hats and two red hats and, in a dark room, placed a hat on each prisoner. then the prisoners were taken into the light where, except for the blind one, they could see one another. none could see the hat on his own head. the game was for any prisoner to state correctly what color that he himself was wearing. the jailor asked one of those who could see and he answered no. the jailor asked the other prisoner who could see and he answered no. the blind prisoner at this point correctly stated the color of his hat, winning the game for all three. how did he know?