The Question of the Locus of Manas

Question: Since consciousness arises from the contact between the sense faculties and their objects, and mental consciousness does not arise anywhere other than at the subtle sense faculty, can it be inferred that the mental faculty (manas) resides within the subtle sense faculty?

Answer: The mental faculty is not entirely confined to the subtle sense faculty either. The entire brain is pervaded and sustained by the mental faculty. The mental faculty does not depart from the location of the subtle sense faculty, yet it is not solely limited to the subtle sense faculty. Beyond the subtle sense faculty, there are mental objects (dharmas). The discernment by the mental faculty must necessarily occur there. Whenever the eighth consciousness (ālaya-vijñāna) manifests a dharma, the mental faculty invariably relies upon the eighth consciousness to apprehend and discern it.