大般涅槃經義記 9.72

9.72

三明業定，六道四生所作之業無互受過。「人作人受」就趣徵定，且就人徵，餘道可知。「婆羅門作婆羅門受」就姓徵定，且就婆羅，餘姓可知。下就設難。「若如是者則不應有下姓、下有」是一難也。婆羅門作婆羅門受，故無下姓，謂無毘舍、首陀等也。人作人受故無下有，謂無地獄、畜生等也。「人應常人，婆羅門應常婆羅門」是二難也。

Third, it clarifies that if karma were determinate, there would be the fault that karma performed in the six destinies and four modes of birth could not be experienced mutually. 'Humans perform it and humans experience it' examines determinacy according to destinies: taking humans as an examination for now, the other destinies can be known. 'Brahmins perform it and Brahmins experience it' examines determinacy according to caste: taking Brahmins for now, the other castes can be known. Below it proceeds to pose the objection. 'If it were like this, then there should be no lower castes or lower states of existence' is the first objection. If Brahmins perform it and Brahmins experience it, then there would be no lower castes, meaning no Vaiśyas, Śūdras, and so forth. If humans perform it and humans experience it, then there would be no lower states of existence, meaning no hells, animals, and so forth. 'Humans should always be humans, and Brahmins should always be Brahmins' is the second objection.