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?
Ljude izvan tog kruga tretiramo kao podljude, koji se mogu iskorištavati bez posljedica. Ali tijekom povijesti, krug se širio. U povijesnim zapisima je vidljivo njegovo širenje od sela na klan, pa na pleme, na naciju, na druge rase, na oba spola, a prema Singeru trebali bi ga proširiti i na druge svjesne vrste. Pitanje je, ako je do toga došlo, što je potaklo to širenje?