大般涅槃經集解 36.49

36.49

案僧宗曰：第三難。謂見有父母等者，名眾生緣。不見父母，但緣五陰眾生之本，離前二心，即空為緣；境既有，就心從境，唯應有三也。

Sengzong states: The third challenge. Perceiving that there are parents and the like is called taking sentient beings as object. Not perceiving parents, but merely taking the five aggregates—the basis of sentient beings—as object, separate from the previous two minds, is taking emptiness as object. Since the objective realm exists, following the mind from the objective realm, there should only be three.