Is the Activity of Manas Located Within the Brain or in the External Void?

If the manas were outside the brain, it would have no relation to oneself. If the manas could exist in empty space, whose manas would that be? Who would execute the results of its deliberation? How could contact between the sense faculties and their objects produce the six consciousnesses to provide feedback for the manas' deliberation? Therefore, it is said that the manas cannot exist in the void outside the brain. What is the realm outside the brain? Is it necessarily empty space? The Śūraṅgama Sūtra states: "Empty space arises within your mind, like a speck of cloud dotting the boundless void." This "mind" certainly refers to the tathāgatagarbha, but must the manas also, along with the tathāgatagarbha, discern empty space? Then, is empty space within the manas or outside it? Or is the manas within empty space or outside it? The manas silently accommodates and discerns all dharmas, unconfined within the physical body; it discerns dharmas of the ten directions and three times along with the tathāgatagarbha. From this, we can see: how vast is our mind? It encompasses the entire universe.

The manas is also a consciousness-mind. The consciousness-mind operates without being inside, outside, or in the middle of the physical body, because the consciousness-mind is formless and shapeless—it cannot be said to be inside or outside the physical body. Yet this consciousness-mind, the manas, can govern all dharmas inside and outside the physical body, functioning together with the tathāgatagarbha. Wherever the tathāgatagarbha is present, the manas necessarily follows. The tathāgatagarbha cannot operate any dharma alone, except for essential objects. Where the manas is absent, there is no life phenomenon. If the manas were absent from the brain, not only would the brain cease to function, the entire physical body would cease to function, and life would not exist. All dharmas contacted by the five aggregates are operated by the tathāgatagarbha and accompanied by the manas; the manas, relying on the tathāgatagarbha, can discern them all. Even dharmas beyond the reach of the five aggregates are operated by the tathāgatagarbha and accompanied by the manas; the manas can likewise discern these dharmas.

For example, if someone recites the Buddha's name and attains samādhi, truly aspiring to be reborn in the Pure Land, then a lotus will appear for them in the lotus pond of the Pure Land. This lotus is not solely manifested by their tathāgatagarbha; rather, the tathāgatagarbha constructs it in the Pure Land's lotus pond in accordance with the manas's vow for rebirth. So, is the manas operating inside or outside the brain? At this time, the manas does not leave the brain or the physical body, yet simultaneously exists in the Pure Land. If it were said that the manas operates only within the brain, how then to explain the lotus in the Pure Land? To whom does it belong? The mind-made bodies of great bodhisattvas are all governed by a single manas. Are the manas of each of their manifestations inside or outside their physical bodies?

Another example: when the eye consciousness sees ten people in front, upon which person's form does the eye consciousness actually make contact? Since it sees all ten people simultaneously, the eye consciousness contacts the forms of all ten at once; it is not said to contact only one person and not others simultaneously. Similarly, the manas, relying on the tathāgatagarbha, can contact all dharmas upheld by the tathāgatagarbha simultaneously, without distinction between inside, outside, or in between. Inside and outside the supreme sense faculty exist the same dharmas; inside and outside the brain exist the same dharmas; the manas can perceive and deliberate upon them all. But the actual situation is that sentient beings possessing a supreme sense faculty, no matter where they go, cannot escape it; even if they run to the edge of heaven, they still remain within it. The manas' constant and thorough deliberation operates upon all dharmas, not only deliberating upon dharmas within the supreme sense faculty but also upon dharmas beyond it. It not only clings to the body but also to dharmas—this clinging is the most difficult to handle. We are currently unable to free ourselves from the clinging and thoughts of the three realms' mundane world; all our thinking is confined due to our limited insight.