瑜伽師地論略纂 5.117

5.117

初二觀，論有兩番釋。初番云：初不淨觀正是念住，以方便念住而為依止；第二不淨觀即後念住，以初念住而為依止者，此約所依加行、根本緣起差別，顯二不淨觀，初緣不淨，後觀骨人故。　「最極通達者，是青瘀等觀」等者，此說白骨觀是不淨觀中最極通達義，是青瘀等後勝次第末後逾越貪等觀義。　第二番云：初不淨觀，觀察內身；後不淨觀，通達法性，此依所緣境界事理淺深緣起差別，顯二不淨觀。根本觀中，不淨境及性二類別故，是故前言斷滅對治。　「觀識流轉」者，釋前觀察斷，即後三觀，謂觀諸識斷與未斷。　「觀察此識生滅相續」是總句，或觀生身，或觀剎那二種識轉。

Regarding the first two contemplations, the treatise has two explanations. The first explanation states: the initial contemplation of foulness is properly the smṛtyupasthāna, taking the preparatory smṛtyupasthāna as its reliance; the second contemplation of foulness is the subsequent smṛtyupasthāna, taking the initial smṛtyupasthāna as its reliance. This reveals the two contemplations of foulness according to the difference between the preparatory and fundamental conditioned arising of their reliance, because the former takes foulness as its object, while the latter contemplates the skeleton. Regarding "The most supreme penetration refers to the contemplation of blue-black discoloration, etc.": this states that the contemplation of white bones has the meaning of the most supreme penetration among the contemplations of foulness, being the contemplation that surpasses greed and so forth at the very end of the progressive stages after blue-black discoloration, etc. The second explanation states: the initial contemplation of foulness observes the internal body; the subsequent contemplation of foulness penetrates the reality of dharmas (dharmatā). This reveals the two contemplations of foulness according to the difference in conditioned arising between the shallowness and depth of the factual and the principled aspects of their cognitive objects. In the fundamental contemplation, because the objective domain of foulness and reality are of two different types, it was previously called the eradicating antidote. "Observing the transcurrent flow of consciousness" explains the earlier observation of abandonment, which refers to the latter three contemplations, meaning observing whether the various consciousnesses are severed or unsevered. "Observing the continuous succession of arising and ceasing of this consciousness" is a comprehensive phrase, either observing the physical body or observing the two kinds of operation of consciousness moment by moment.