因明入正理論疏 2.176

2.176

述曰：結不定。無質礙因，空為同品能成聲常，樂為同品能成無常，由成二品，是故如前亦為不定。《理門論》云：「若於其中俱分是有，亦是定因，簡別餘故，是名差別。」謂此第五俱分之因，於同、異品皆悉分有，是不定因，由有相違及正因故。此所說因，不於一分異品轉故，是定因攝。如立聲常宗，無質礙故因。諸無質礙皆悉是常，猶如虛空為同喻。若是無常，即有質礙，猶如瓶等為異喻。空為同品，無質礙因有，瓶為異品，無質礙因無，故是其正。若望樂等心、心所法，異品有故即是相違。謂聲無常，無質礙故，如心、心所。謂若是常，見有質礙，猶如極微。今此不定因，望異品一分無邊，可是決定；若望異品一分有邊，即成相違，故是猶預。或於其中俱分有者，非唯此一，第一、第三、四、五皆名俱分，並有此義。同品、異品名為俱分，非俱一分名為俱分。若作後解，攝不定盡。前不共因無有定義，宜簡別自餘不定因故，是名不定，與餘差別。次上二因唯有二段，無第三段，指不定相同前第三，易故不說。此亦有三：如大乘師對薩婆多立他比量：「汝之命根非是異熟，以許非識故，如許電等。」此非異熟宗，以非業果五蘊、無為而為同品，許非識因，於電等有、於心等無。以業果五蘊而為異品，許非識因，於心等無、於眼等有，故是他俱品一分轉。小乘返立，即自俱品一分轉。如論所陳，即是共俱品一分轉。

Commentary: This concludes that it is inconclusive. With the reason "lacking tangible obstruction," taking space as the homologue can establish that sound is permanent, and taking pleasure as the homologue can establish that it is impermanent; because it establishes both classes, as before it is also inconclusive. The Nyāyamukha states: "If among them there is presence in parts of both, it is also a conclusive reason; because it differentiates the rest, it is called a specific difference." This means that this fifth reason, which is present in a part of both the homologue and the heterologue, is an inconclusive reason because it possesses both contradictory and correct reasons. Because the reason stated here does not occur in one part of the heterologue, it is subsumed under conclusive reasons. For instance, when establishing the thesis that sound is permanent by the reason "because it lacks tangible obstruction," "whatever lacks tangible obstruction is permanent, just like space" is the homologous example; "if it is impermanent, it has tangible obstruction, just like a jar and the like" is the heterologous example. Taking space as the homologue, the reason "lacking tangible obstruction" is present; taking jars as the heterologue, the reason "lacking tangible obstruction" is absent; therefore it is correct. If viewed with respect to mental factors such as pleasure and the like, because it is present in the heterologue, it is contradictory. That is: "Sound is impermanent, because it lacks tangible obstruction, like mind and mental factors; for if it is permanent, it is observed to have tangible obstruction, just like atoms." Now this inconclusive reason, viewed with respect to the aspect of absence in a part of the heterologue, could be conclusive; if viewed with respect to the aspect of presence in a part of the heterologue, it becomes contradictory; therefore it causes hesitation. Alternatively, "presence in parts of both among them" is not limited to this one alone: the first, third, fourth, and fifth are all called "parts of both" and all possess this meaning. The homologue and heterologue together are called "both parts," not that "a part of both" is called "parts of both." If interpreted in the latter way, it exhausts all inconclusive reasons. The preceding uncommon reason lacks any conclusive meaning; because it is suitable to differentiate it from all the other inconclusive reasons, it is called inconclusive, as its difference from the rest. The two reasons just above have only two sections and lack the third section, pointing back to the characteristic of inconclusiveness as being the same as the third preceding one; because it is easy, it is not stated. This also has three varieties: For example, a Mahāyāna master establishing an inference for the other against a Sarvāstivādin: "Your life-faculty is not a karmic maturation, because you accept that it is not consciousness, like lightning and the like accepted [by you]." In this thesis of "not being a karmic maturation," the five aggregates that are not karmic fruits and the unconditioned are the homologues; the reason "accepting that it is not consciousness" is present in lightning and the like and absent in mind and the like. Taking the five aggregates that are karmic fruits as heterologues, the reason "accepting that it is not consciousness" is absent in mind and the like and present in the eye[-faculty] and the like; therefore it is an inference for the other that occurs in a part of both classes. If the Hīnayānist establishes the reverse, it is an inference for oneself that occurs in a part of both classes. What is set forth in the treatise is an inference for both that occurs in a part of both classes.