Because they are units or systems, they do possess at their outer limits a resistance which serves to give them unitary identity, a resistance which tends to attract like and repel unlike elements.
因为它们是单元或系统,所以它们确实在它们的外部边界具有阻力,起到为它们提供单一身份的作用,
种阻力趋向于吸引同类元素、排斥异己元素。