Why Must the Five Consciousnesses Discern the Five Sense-Objects Through the Manas's Decision-Making?

Question: When my body itches, I can't help wanting to scratch it, but then I realize that this is all just the body consciousness contacting the sense-object—where is the itch? Don't fabricate. So I stopped attending to that spot, and the itch immediately disappeared. If I continued to attend to it, the itch remained; when I stopped attending again, the itch disappeared again. This went back and forth twice, with a slightly longer interval in between, and once I stopped attending altogether, the itch disappeared completely. Did the itch truly disappear?

Answer: When the sense faculty and sense-object contact each other, consciousness arises; once consciousness is born, it discerns the sense-object realm. After discernment, feelings arise—sensing cold, heat, touch, pain, itch, and so on—and afterward the emotions of suffering, happiness, sorrow, joy, and neutral feeling arise. This is the sequence of operation of the six sense bases (ṣaḍāyatana), contact, and feeling among the twelve links of dependent origination. Whether the faculty and sense-object come into contact is determined by the manas. For example, when the body itches, if the manas does not attend to the itchy spot and shifts its attention elsewhere, then the mind consciousness and body consciousness cannot arise at the itchy spot, the itch as a sense-object of contact is not discerned, feelings do not arise, and one does not know of the itch or feel the itch. This is the manas shifting its attention, causing the six consciousnesses not to arise at that spot and thus not to discern it—it is not that there is no itch. If the manas does not shift its attention, and the body faculty remains with the sense-object of the itch, then the body consciousness and mind consciousness arise and discern the sense-object of the itch, and one will feel itchy; afterward the manas will choose to scratch, and so the body consciousness and mind consciousness scratch the itch.

This shows that the manas is the consciousness that makes decisions—it governs the contact between faculties and sense-objects, governs the arising, ceasing, coming, and going of the six consciousnesses, governs the discernment of the six consciousnesses, and governs bodily, verbal, and mental actions. This also shows that whether the five faculties—eye, ear, nose, tongue, and body—come into contact with the five sense-objects of sight, sound, smell, taste, and touch is all decided by the manas, and the discernment by the five consciousnesses is also decided by the manas. Herein lies a question: why does the manas govern the arising and discernment of the five consciousnesses? Why is the discernment of the five sense-objects by the five consciousnesses decided by the manas? Since the manas is capable of such decision-making, He must first have discerned the five sense-objects before He could take up or reject them, make judgments and decisions. This shows that the manas can discern the six sense-objects, and does not merely discern the mental sense-object alone; otherwise, how could the five faculties contact the five sense-objects, and how could the five consciousnesses arise?