俱舍論疏 5.197

5.197

論「謂住之異至無不遍失」，經部答也。謂住之異故，若有住必有異也。謂最後聲、光等，嗣前起故名住，此即名住最後聲、光，異其前念名為住異。即住名異，故名住異也。非是待後剎那前方名異，亦非待後剎那前方名住。理必應然。只可後異前故名之為異，不可前異於後名之為異。若異於前，異由於自；若異於後，異乃由他。

On the treatise passage: "It means the alteration of staying … no fault of failing to pervade": the Sautrāntika replies. It refers to the alteration of staying; hence wherever there is staying, there is necessarily alteration. That is to say, the final sound, light, and so forth are called "staying" because they arise in succession to the preceding; this very staying of the final sound and light, by differing from its preceding thought-moment, is termed "the alteration of staying". This staying itself is termed "alteration", and hence it is called "decay-cum-alteration". It is not that it is called "alteration" only by waiting for a subsequent moment, nor is it that it is called "staying" only by waiting for a subsequent moment. In principle it must be so: it can only be called "alteration" because the subsequent differs from the prior; one cannot say the prior differs from the subsequent to call it "alteration". If it differs from the prior, the difference depends on itself; if it differs from the subsequent, the difference depends on another.