Let us suppose that you are confronted with a wall. On the
other side of that wall are two separate rooms. There is a door between these
two rooms. In one room is a hungry, man-eating tiger. In the second room, there
may or may not be a human being.
You are presented with a lever. If you pull the lever, the
door between the two rooms will open and the hungry, man-eating tiger will be
able to enter the other room. If there is no human in the other room, then no
life will be terminated. If there is a human in the other room, then that human
will be killed by the hungry, man-eating tiger.
Therefore, if you are uncertain as to whether or not there is
a living person in the other room but are given the free choice on whether or
not to pull the lever, do you, in uncertainty, choose to pull the lever?