What the manas knows, the mind consciousness does not necessarily know

Question: Sometimes when walking, I cannot see whether someone is following behind me, yet I can know that someone is behind me. How do I know this? Are the people and objects behind me the inner representation within the back of the brain? Can material sense-objects enter the supreme faculty at the back of the brain without being transmitted through the eye faculty?

Answer: People and objects behind you cannot be transmitted through the eye faculty into the supreme faculty at the back of the brain, because the eye faculty does not face the back of the head. In the Śūraṅgama Sūtra, the Buddha said that among the twelve hundred merits, the eye faculty possesses only eight hundred merits, meaning that the eye faculty can contact material sense-objects directly in front, and two-thirds on each side to the left and right, but cannot contact the rest. Therefore, knowing that someone is following behind you—this knowing is the Image-Only Object mental sense-object known by the solitary mental consciousness; it cannot know material sense-objects. This Image-Only Object mental sense-object is contacted and known by the manas. When the manas considers it important, it alerts the mind consciousness to know it. The manas knows a great many dharmas, but cannot express them, and the mind consciousness has no way to know what the manas knows, so the mind consciousness does not know. Some people say "I don't know," but in fact the manas does know.

Sneezing is a sudden event; the mind consciousness has no mental preparation for it, so it is initiated by the manas. When a ghost arrives, the mind consciousness does not know, but the body will shiver—this is triggered by the manas. When a major event is about to occur, the mind consciousness does not know what it is, but one will feel inexplicably happy or distressed—this is initiated and hinted at by the manas.