The Scope of the Manas's Regulation over the Physical Body

The black box refers to the five supreme faculties (rūpa-prasāda) in the brain, including the visual perception area, the auditory perception area, the olfactory perception area, the tactile perception area, the motor central nervous system, and the language central nervous system; it includes part of the brain, the telencephalon, the brainstem, and the cerebellum, and so on, but does not include the cerebral cortex. The cerebral cortex is regulated solely by the manas; the manas is responsible for all brain activity, which even the mind consciousness does not understand. Therefore, the range of activity of the mind consciousness is smaller than the range of activity of the manas.

Whatever changes, movements, and activities of the physical body belong to the scope of the aggregate of formations (saṃskāra), and are directly regulated by the manas. The body consciousness and the mind consciousness participate, but there is not necessarily the mind consciousness's deliberation, analysis, and direction involved. When the manas grasps these activities as self and as belonging to self, this is the self-view (ātma-dṛṣṭi). However, the autonomous activities of the physical body, such as the activities of the internal organs—heartbeat, pulse, gastrointestinal peristalsis, the metabolism of cells and tissues, the growth of nails and hair, and so on—are not regulated by the mind consciousness or the manas; they are activities by which the tathāgatagarbha sustains the living organism in accordance with karmic seeds and karmic conditions.

External activities of the body necessarily involve the participation of the mind consciousness and the body consciousness. It is only that on familiar stretches of the road, without the mind consciousness's deliberation and direction, the manas can lead the mind consciousness and the body consciousness to complete that stretch of road. If that stretch of road is unfamiliar, the manas must rely on the guidance of the mind consciousness's deliberation and analysis in order to lead the mind consciousness and the body consciousness to complete that stretch of road. The metabolism of cells, the changes in tissue structure, and the growth and changes of muscles and bones are not controlled by the manas or the mind consciousness; they all change in accordance with karmic seeds and karmic conditions.