大般涅槃經集解 20.60

20.60

案僧宗曰：百草之中亦應有乳，如是乳中亦有草者，草為因也，乳為果也。若使因中有果者，果中亦可有因，是則反覆有過也。

Sengzong states: Among the hundred grasses there ought also to be milk; likewise, if there is grass within milk, grass is the cause and milk is the fruit. If there were the fruit within the cause, there could also be the cause within the fruit, and this would repeatedly entail errors.