俱舍論記 22.31

22.31

「應知此中至物亦有殊」者，出四諦體。問：四諦若依實體應唯有三，苦、集一物故。若依因果應有五種，於道諦亦有因果。若依現觀應有八種，上、下八諦故。答：如《婆沙》云「復次依現觀故建立四諦。問：若爾，聖諦應八非四。答：諦行相同，故四非八。」廣如彼釋。

Regarding "'It should be known that herein' up to 'their entities are also distinct'": this sets forth the essence of the four truths. Question: If the four truths were based on real entities, there should only be three, because suffering and origination are a single entity. If based on cause and fruit, there should be five kinds, because there are also cause and fruit within the truth of the path. If based on direct realization, there should be eight kinds, because there are eight higher and lower truths. Answer: As the Mahāvibhāṣā says: "Furthermore, the four truths are established on the basis of direct realization. Question: If so, there should be eight noble truths, not four. Answer: Because the aspects of the truths are the same, there are four and not eight." This is as extensively explained there.