Fall 2006

Prof. Teuber

# The Trolley Problem With Bridge and Trap DoorVariation on a Theme

John is the driver of a trolley, whose brakes have failed. On the track ahead of him are five workmen; the banks are so steep that they will not be able to get off the track in time. Unlike the original case of the problem, in this case there is no spur leading off to the right, and John cannot turn the trolley onto it.

There is, however, a steel bridge over the tracks on which a man is standing, leaning over the railing enjoying the view. Imagine a view. He is standing on the bridge directly over the tracks and directly under which the trolley with its failed brakes and John will travel.

At the moment the bridge happens to be equidistant between the trolley and the five workmen below. The man on the bridge is at the center of the bridge and could leap onto the tracks and try to stop the trolley but he is enjoying the view and does not see what's coming.

As luck would have it, however, there is a trap door and the man is standing on it. The trap door is closed, but if opened it is obvious from the situation that he would fall onto the tracks directly into the path of the oncoming trolley. If this were to happen, it is also clear that his body would become caught under the wheels of the trolley and he would die, but it would block the trolley from any further descent and the trolley would come to a halt before it reaches the five men working on the tracks.

You happen to be in a booth next to the bridge and can press a plunger. The plunger, if pressed, will open the trap door and deposit the man onto the tracks. Do you press the plunger? If you do, you stop the trolley and spare the five workmen, saving five for the price of one.

What should be done? What would you do?

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