Prominent scientists are in a bitter struggle over the origins of kindness. But the root of this conflict may be the most ironic part of all.
What would it take for you to give your life to save another? The answer of course is two siblings or eight cousins, that is, if you’re thinking like a geneticist. This famous quip, attributed to the British biologist J.B.S. Haldane, is based on the premise that you share on average 50% of your genes with a brother or sister and 12.5% with a cousin. For altruism to be worth the cost it should ensure that you break even, genetically speaking.