The British philosopher Herbert Spencer described this struggle as "survival of the fittest."

VOA: special.2009.02.25

If evolution is survival of the fittest, nature red in tooth and claw, how could animals evolve moral feelings?

如果进化论是讲适者生存，在弱肉强食的自然界，动物怎么能进化出道德情感？

耶鲁公开课 - 心理学导论课程节选