Assume now you are on a bridge overlooking the track. Ahead, five people on the track are at risk. You can save them by throwing down a heavy object into the path of the approaching train. One is available beside you, in the form of a fat man. Is it OK to push him to save the five? Most people say no, although lives saved and lost are the same as in the first problem.

Why does the moral grammar generate such different judgments in apparently similar situations? It makes a distinction, Hauser writes, between a foreseen harm (the train killing the person on the track) and an intended harm (throwing the person in front of the train), despite the fact that the consequences are the same in either case. It also rates killing an animal as more acceptable than killing a person.

—NICHOLAS WADE / (New York Times)