Is the activity of the manas within the brain or in the void outside the brain?

If the manas were outside the brain, it would have nothing to do with oneself; and if the manas could exist in empty space, whose manas would that be? Who would carry out the results of its deliberation? How could the faculties and sense-objects come into contact to give rise to the six consciousnesses to feed back the manas's deliberation? Therefore it is said that the manas cannot possibly be in the empty space outside the brain. What lies outside the brain? Must it necessarily be empty space? The Śūraṅgama Sūtra says: 虚空生汝心内，如片云点太清里。This mind, of course, refers to the tathāgatagarbha, but does the manas also, following the tathāgatagarbha, discern empty space? Then is empty space inside or outside the manas? Or is the manas inside or outside empty space? The manas silently embraces and discerns all dharmas, and is not confined or obstructed within the physical body; the dharmas of the ten directions and the three times can all be discerned by means of the tathāgatagarbha. From this we can see: how large is our mind, ultimately? It encompasses the great void.

The manas is also a conscious mind. The conscious mind does not operate inside, outside, or in the middle of the physical body, because the conscious mind is formless and without appearance; one cannot say that the conscious mind is inside the physical body or outside it. And the manas, this conscious mind, can govern all dharmas both inside and outside the physical body, operating together with the tathāgatagarbha. Wherever the tathāgatagarbha is, the manas is surely following along; the tathāgatagarbha cannot operate any dharma on its own, except for the essential objects. Where the manas is absent, there is no phenomenon of life. If the manas were absent from the brain, not only could the brain no longer function, the entire physical body could no longer function, and life would not exist. The dharmas that the five-aggregate body can contact are all operated by the tathāgatagarbha, and all have the manas following along; the manas, relying on the tathāgatagarbha, can discern them all. And the dharmas that the five-aggregate body cannot contact are likewise operated by the tathāgatagarbha, and likewise have the manas following along; the manas can discern these dharmas just as well.

For example, if someone engages in recollection of the Buddha (buddhānusmṛti) and attains meditative concentration (samādhi), truly wishing to be reborn in the land of bliss (Sukhāvatī), then a lotus flower will appear for him in the lotus pond of the land of bliss. This lotus is not merely manifested by his tathāgatagarbha; rather, the tathāgatagarbha, following the manas that has made the vow of rebirth, builds it in the lotus pond of the land of bliss. So does the manas operate inside the brain or outside it? At that time, the manas neither leaves the brain nor the physical body, and yet is at the same time in the land of bliss. If the manas could only operate inside the brain, then what about the lotus in the land of bliss? Whose does it belong to? The mind-made bodies of all the great bodhisattvas are governed by a single manas; is the manas of each emanated body inside or outside the physical body?

Again, for example, when the eye consciousness sees ten people in front of it, upon which person's form does the eye consciousness actually make contact? Since it sees ten people simultaneously, the eye consciousness contacts the forms of all ten people at the same time; it is not the case that it can only contact one person and cannot contact the others simultaneously. The manas is also like this: relying on the tathāgatagarbha, it can simultaneously contact all the dharmas held and sustained by the tathāgatagarbha, without distinguishing inside, outside, or the middle. Inside and outside the supreme faculty there are the same dharmas; inside and outside the brain there are the same dharmas; the manas can take them all as its objects and can deliberate upon them all. But the actual situation is that sentient beings who possess a supreme faculty, no matter where they go, cannot escape their supreme faculty; even if they run to the edge of the sky, they still cannot get out of the supreme faculty. The manas's continual scrutiny and deliberation is upon all dharmas; it deliberates not only on the dharmas within the supreme faculty, but also on the dharmas outside the supreme faculty. He not only grasps the body, but also grasps dharmas—and this grasping is the hardest thing to deal with: the worldly attachments of the three realms, which even now we are unable to free ourselves from; all our thinking is constrained by them, because our insight is limited.