Moral emotions like empathy are as much an outcome of the blind workings of adaptation as our upright stance and opposable thumbs – traits that are entrenched in a species through the proliferation of particular genes. We humans are most strongly empathetic toward those who share the greatest proportion of our genes: our children, our parents, our siblings, and, by lessening gradations, our extended family and tribe.
同情等道德情感和直立行走和可弯折的大拇指一样，都是适应的不择向的作用，是物种通过特定基因的繁衍而获得的特征。我们人类最同情那些与我们共享最大比例基因的物种：我们的孩子、父母、手足，以及等级次之的大家庭和部落。我们对他们的同情甚至推动我们作出威胁我们个体生存的牺牲，但这对于保护我们的共有基因来说完全正确。