俱舍論頌疏論本 6.40

6.40

釋曰：唯諸不善及善有漏，是異熟因，異熟法故。問：「何緣無記不招異熟？」答：「由力劣故，如朽敗種。」問：「何緣無漏不招異熟？」答：「無愛潤故，如貞實種無水潤沃，又非繫地，如何能招繫地異熟？餘法具二，是故能招。如貞實種，水所沃潤。」言異熟者，依薩婆多宗，因是善惡，果是無記，異類而熟，名為異熟。俱有等四，因唯同類熟，謂因與果俱性同故，能作一因，兼同異熟，謂有同性果、有異性果。故今異熟因唯異類熟，故唯此一名異熟因。

The explanation says: Only the unwholesome and the wholesome with out-flows are maturation causes, because they are phenomena of maturation. Question: "For what reason does the indeterminate (avyākṛta) not incur maturation?" Answer: "Because its power is weak, like a rotten seed." Question: "For what reason does the undefiled not incur maturation?" Answer: "Because it lacks the moistening of craving, like a sound and solid seed without the moistening irrigation of water. Furthermore, it is not bound to a stage; how could it incur a maturation bound to a stage? Other phenomena possess both [characteristics], and therefore are able to incur it, like a sound and solid seed irrigated by water." Regarding "maturation" (vipāka): according to the Sarvāstivāda school, the cause is wholesome or unwholesome, and the fruit is indeterminate; ripening in a different nature (visabhāgaṃ pacyate) is termed maturation. The four causes such as the co-existent [cause] ripen only as similar kinds, meaning that cause and fruit share the same moral nature. The one efficient cause (kāraṇahetu) combines both similarity and difference in ripening, meaning it has fruits of the same nature and fruits of a different nature. Therefore, the maturation cause here ripens exclusively in a different nature; hence this one alone is named the maturation cause.