成唯識論述記 5.951

5.951

述曰：不應《瑜伽》受中唯說容受，意中通說主識，主識即第八，以第八識必受俱故，無異所以，別作論故。

The Commentary states: That Yogācārabhūmi should not, among sensations, speak only of circumstantial sensations, while among the mental faculty, speak generally of the principal consciousness; the principal consciousness is the eighth consciousness, because the eighth consciousness is necessarily associated with sensation, and there is no different reason to formulate the treatise differently.