People outside that circle are treated as sub-human, and can be exploited with impunity. But, over history, the circle has expanded. One can see, in historical record, it expanding from the village, to the clan, to the tribe, to the nation, to other races, to both sexes, and, in Singer's own arguments, something that we should extend to other sentient species. The question is, if this has happened, what has powered that expansion?
在圈外的人们被认为是次等人， 可以利用。但是经过历史， 圈子已经扩张了。可以看到的是，历史记录， 它从乡村扩张到氏族，扩张到部落， 扩张到国家，扩张到其他种族，扩张到两性 并且，在辛格自己的论文中，一些我们应该扩张到 其他有感情的物种的东西。问题是， 如果真是实现了，是什么驱使这种扩张？