You're the driver of a runaway trolley about to hit and certainly kill five people on the track ahead, but you have the option of switching to a second track at the last minute, killing only a single person. What do you do?
You are the owner of a driverless car that is programmed to sacrifice you if necessary in order to save a certain number of other people. What number would you want that to be? Would you tell it to make exceptions for different people?