Students of ethics love to discuss the trolley dilemma, which Wikipedia defines in the following way:
There is a runaway trolley barrelling down the railway tracks. Ahead, on the tracks, there are five people tied up and unable to move. The trolley is headed straight for them. You are standing some distance off in the train yard, next to a lever. If you pull this lever, the trolley will switch to a different set of tracks. However, you notice that there is one person on the side track.
You have two options:
(1) Do nothing, and the trolley kills the five people on the main track.
(2) Pull the lever, diverting the trolley onto the side track where it will kill one person. Which is the correct choice?