人的天性中也许没有贵贱,但一定有亲疏。亲情是人伦重要的一项,也是维系整个人类社会的纽带。当威尔杜朗特评价柏拉图在《理想国/乌托邦》中表达出来的消灭家庭、共产共妻的共产主义思想萌芽时说:“And above all he forgot that in abolishing the family he was destroying the great nurse of morals and the chief source of those cooperative and communistic habits which would have to be the psychological basis of his state; with unrivaled eloquence, he sawed off the branch on which he sat.”