中觀論疏 2.9

2.9

次明「不一不異」者，世諦雖離性實生滅及決定斷常，猶恐墮於一異。如僧佉與大眾部明因果一體，衛世與上座部明因果異體，如此一異並壞世諦因果中道，故次明不一不異。問：世諦因果云何不一不異耶？答〈觀法品〉云「眾因緣生法，不即因、不異因，以因果不同、能所二義，何得為一？因名果因、果名因果，云何得異？故稱中道。」

Next, to explain "neither identical nor different": although conventional truth is free from real intrinsic production and cessation as well as determined annihilation and permanence, there is still the fear of falling into identity or difference. For example, the Sāṃkhya and the Mahāsāṃghika explain cause and effect as having the same substance, while the Vaiśeṣika and the Sthaviravāda explain cause and effect as having different substances. Identity and difference such as these both undermine the middle way of cause and effect in conventional truth; therefore, "neither identical nor different" is explained next. Question: How are cause and effect in conventional truth neither identical nor different? Answer: The chapter "Examination of Dharmas" states: "Dharmas arisen from various causes and conditions are neither identical with the cause nor different from the cause." Since cause and effect are not the same, having the two senses of agent and object, how could they be identical? Because the cause is named the cause of the effect, and the effect is named the effect of the cause, how could they be different? Therefore, it is termed the middle way.