1. The Trolley Problem

2. Scenario 1 A trolley is running out of control down a track. In its path are five people who have been tied to the track by a mad philosopher. Fortunately, you could flip a switch, which will lead the trolley down a different track to safety. Unfortunately, there is a single person tied to that track. Should you flip the switch or do nothing?

3. Scenario 2 As before, a trolley is hurtling down a track towards five people. You are on a bridge under which it will pass, and you can stop it by dropping a heavy weight in front of it. As it happens, there is a very fat man next to you - your only way to stop the trolley is to push him over the bridge and onto the track, killing him to save five. Should you proceed?

4. Scenario 3 As before, a trolley is hurtling down a track towards five people. As in the first case, you can divert it onto a separate track. On this track is a single (fat) person. However, beyond that person, this track loops back onto the main line towards the five, and if it weren't for the presence of that (fat) person, who will stop the trolley, flipping the switch would not save the five. Should you flip the switch?

5. Scenario 4 As before, a trolley is hurtling down a track towards five people. You can divert its path by colliding another trolley into it, but if you do, both will be derailed and go down a hill, and into a yard where a man is sleeping in a hammock. He would be killed. Should you proceed?

6. Scenario 5 As before, a trolley is hurtling down a track towards five people. You can flip a switch and divert the train to run one person over instead of five, but that person is your mother. Would you flip the switch?

7. Scenario 6 A brilliant transplant surgeon has five patients, each in need of a different organ, each of whom will die without that organ. Unfortunately, there are no organs available to perform any of these five transplant operations. A healthy young traveler, just passing through the city the doctor works in, comes in for a routine checkup. In the course of doing the checkup, the doctor discovers that his organs are compatible with all five of his dying patients. Suppose further that if the young man were to disappear, no one would suspect the doctor.