俱舍論疏 8.139

8.139

「論曰至而生類等」，此明立四所以。以生類等同名一生。《正理論》云「前所說界通情、非情（此即界寬，四生狹也）。趣唯有情，然不遍攝（不攝中有，狹於生也）。生唯遍攝，故說有情，無非有情名眾生故。」准此，有情名為眾生，無情不名眾生。舊譯有情名眾生者，有兩名也。准《大乘同性經》，具六界故名眾生也。又云「然有情類卵生、胎生、濕生、化生是名為四（釋四生也）。生謂生類，諸有情中雖餘類雜，而生類等，言生類者是眾生義（准此論文，多生類故名為眾生）。若爾，界、趣亦應名生（問也）。不爾。界通情、非情故。趣雖有情，而非遍故。此唯情遍，獨立生名。」

"The Śāstra says [...] yet their classes of birth are equal." This clarifies the reason for establishing the four: because their classes of birth are equal, they are jointly termed a 'birth'. The Nyāyānusāra says: "The realms spoken of before encompass both sentient and non-sentient (this means realm is broader, while the four births are narrower). Destinies comprise only sentient beings, yet they do not universally subsume them (they do not subsume the intermediate existence, and so are narrower than births). Births alone subsume them universally, and therefore are said of sentient beings, for there are no non-sentient beings called 'sentient beings' (sattva)." According to this, sentient beings are called sattva; the non-sentient are not called sattva. The older translation rendering sattva as 'living beings' (zhongsheng) has two designations. According to the Mahāyāna Samatā-dharmatā Sūtra, because they possess the six elements they are called 'living beings' (zhongsheng). It also says: "However, the classes of sentient beings are egg-born, womb-born, moisture-born, and apparitionally born; these are called the four (explaining the four births). 'Birth' means class of birth. Although among sentient beings other classes are intermingled, their classes of birth are equal; to say 'class of birth' is the meaning of living beings (according to this text, having many classes of birth is why they are called living beings). If so, should realms and destinies also be called births? (This is a question.) It is not so. For realms encompass both the sentient and the non-sentient. Destinies, though consisting of the sentient, are not universal. Births alone are universal to the sentient, and so independently receive the name 'birth'."