因明入正理論疏 2.24

2.24

述曰：別指法也。如無常宗，是常為異，所作性因，非作為異。返顯義言，於常品中既見非作，明所作者定見無常。同成宗故，先因後宗，異法離前，宗先因後。若異離中因先宗後，如言非作定是常住，翻成本來非諍空常住，非是離前成於無常之宗義也。若成常住，便犯相符，舊已定宗，今成立故。同既成立，先因後宗，異既離前，隨宗先後，意欲翻顯前成立義。今者宗無，因既不轉，明因有處宗必定隨。異但說離，離成即得，必先宗無後因無也。故《理門》云：「說因宗所隨，宗無因不有。」如空等者，此舉喻依，以彰喻體，標其所依有法，顯能依之法非有。等者，等取隨所應宗涅槃等法。

The commentary states: This specifically designates the property. For instance, in the proposition that [sound is] impermanent, being permanent is the heterogeneous [property]; in the reason of being a product, being not a product is the heterogeneous [property]. To elucidate the meaning conversely: since in the class of permanent things they are seen to be not products, it is clear that what is a product is definitely seen to be impermanent. Because [the homogeneous example] homogeneously establishes the proposition, the reason comes first and the proposition comes second; because the heterogeneous property separates from the preceding, the proposition comes first and the reason comes second. If, in the heterogeneous separation, the reason came first and the proposition came second—as in saying that what is not a product is definitely permanent—it would turn around and establish the original, uncontested permanence of space, rather than separating from the preceding to establish the proposition of impermanence. If it established permanence, it would incur [the fault of] proving what is already accepted, establishing now what was already settled formerly. Since the homogeneous establishes, the reason comes first and the proposition second; since the heterogeneous separates from the preceding, it follows the sequence of the proposition, with the intention of conversely elucidating the previously established meaning. Now, when the proposition is absent, since the reason does not occur, it is clear that where the reason exists, the proposition must definitely follow. The heterogeneous merely states separation; if separation is achieved, that suffices, and it must put the absence of the proposition first and the absence of the reason second. Therefore the Nyāyamukha states: "It is stated that the proposition follows the reason, and that where the proposition is absent, the reason does not exist." As for "like space, etc.," this adduces the locus of the example to illustrate the entity of the example, indicating the subject that serves as the locus to demonstrate that the property that relies upon it does not exist. "Etc." includes, in accordance with the proposition as appropriate, things such as nirvāṇa.