成唯識論述記 4.213

4.213

述曰：此敘彼宗。是識轉變剎那即滅，識上假、立一類不變，無別前後，識類是一，故此可熏，亦可持種。識既被遮，故須計類。因類既成，何勞第八？

The Commentary states: This presents their thesis. These consciousnesses change and perish moment by moment, but upon consciousness there is nominally designated a uniform category that does not change and has no distinct before and after; the category of consciousness is one, and therefore this can be perfumed and can also hold seeds. Since consciousness itself was refuted, they had to posit the category. Since the category is established as the cause, why labor [to establish] the eighth?