成唯識論述記 5.373

5.373

述曰：次破第二，六遍師義。起煩惱時若無惛沈，此染污心應不定有無堪任性。若有堪任便是善性，非染心攝；名堪任故；如善心性。染心若有無堪任性，異於善者，有惛沈故。《對法》等云：惛沈性者無堪任性；又云：離無堪任染性不成。是故惛沈定遍染起，故起掉時既是染心，惛沈定有。

The Commentary states: Next, refuting the second master, the proponent of six universals. When afflictions arise, if there were no torpor, this defiled mind would not necessarily possess incompetence. If it possessed competence, it would be wholesome in nature and not included within defiled minds; because it is called competence, just like the wholesome mental nature. If a defiled mind possesses incompetence and is distinguished from the wholesome, it is because torpor exists. The Abhidharma[-samuccaya-vyākhyā] and other texts state: "The nature of torpor is incompetence"; they also state: "Apart from incompetence, a defiled nature is not established." Therefore torpor definitely arises universally pervading defilement; thus, when restlessness arises, since it is a defiled mind, torpor definitely exists.