Is 'Do Unto Others' Written Into Our Genes?

Is 'Do Unto Others' Written Into Our Genes? By NICHOLAS WADE The New York Times

Many people will say it is morally acceptable to pull a switch that diverts a train, killing just one person instead of the five on the other track. But if asked to save the same five lives by throwing a person in the train's path, people will say the action is wrong. This may be evidence for an ancient subconscious morality that deters causing direct physical harm to someone else. An equally strong moral sanction has not yet evolved for harming someone indirectly.