成唯識論了義燈 5.191

5.191

《論》：一門轉故。西明云：一意根門轉故。今謂不然，既有色根何不依轉？即應解云：猶無五識，不作是釋，更無別因。若云：猶昧略故，定既明廣，何不依彼五色根門？又復下文明五俱意，非專為了五識所緣。又於彼所緣能明了取。故知一門轉，明唯一意識。若一根門，應言依一門轉。

Regarding the treatise's statement, "because it functions through a single gate": Ximing says that it means functioning through the single gate of the mental faculty (manas). Now I maintain that this is not so: since there are material faculties, why would it not function relying on them? Then one should explain: it is still because the five consciousnesses are absent. If one does not make this explanation, there is no other cause. If one says that it is because [the state of sleep] is dim and contracted, then since concentration is clear and expansive, why does it not rely on those five gates of material faculties? Furthermore, a passage below explains that the mental consciousness accompanying the five [sensory consciousnesses] does not exclusively cognize that which is taken as object by the five consciousnesses, and moreover is able to clearly grasp that object. Therefore, one knows that "functioning through a single gate" clarifies that it is solely the single mental consciousness. If it meant a single faculty-gate, it should have said "functioning relying on a single gate."