A trolley is careering out of control. Up ahead are five workers; on a spur to the right stands a lone individual. You, a bystander, happen to be standing next to a switch that could divert the trolley, which would save the five, but sacrifice the one--do you pull it? Or say you're watching from an overpass. The only way to save the workers is to drop a heavy object in the trolley's path. And you're standing next to a really fat man.... This ethical...