The dharmas of the manas are more profound and subtle than those of the mind consciousness.

When asleep, because one feels the blanket is heavy, one turns over automatically, yet at that moment one is not aware of it oneself — are there body consciousness and mind consciousness at this time? Turning over is also a functional activity of consciousness. The sense faculties are themselves passive receivers and transmitters; without consciousness, the faculties would be mere wood and stone. When the manas wants to turn over, the six consciousnesses emerge and make the body move; at this time there is faint body consciousness and mind consciousness. Why does the manas take charge of turning over? Because it discerns that the blanket is heavy; the manas contacts this mental sense-object and knows it affects the body, so it summons the body consciousness and mind consciousness to come out and discern it. When the body consciousness and mind consciousness feel the heaviness, the manas decides to turn over, and thus the body consciousness and mind consciousness turn over together. If one turns over a bit more frequently, sleep will be poor, and the next day one feels physically exhausted, because the six consciousnesses keep appearing and the body has not rested well. If turning over in sleep were not the function of the six consciousnesses, then when one is in a coma and the manas wants to move the body, it should be able to move it; yet in a coma, the body cannot move — although the manas constantly wants the body to become active and to make oneself wake up, it cannot do so.

When turning over in the middle of the night, because the body is fatigued and the mind consciousness is weak, one may not necessarily be able to introspect on one's own operation; the degree of strength or weakness of the mind consciousness differs, and so does the power of introspection (pratyavekṣā-bala). Therefore, some people know what state they were in during the night and what they did; others do not know. When one does not know, sleep is deep and the quality of sleep is good; yet there is still a rapid and faint discernment by the mind consciousness. When the mind consciousness is faint, one can hardly feel the mind consciousness's own existence and operation, and the manas's function stands out. Much of what the manas directly discerns, the mind consciousness does not necessarily know; and since the manas has no names and words, it cannot express it.

The manas silently encompasses all dharmas, whereas the mind consciousness does not; therefore, what the manas discerns must always be more than what the mind consciousness discerns, and far more subtle and profound than the mind consciousness. Hence the dharmas of the manas are deeper, subtler, and more important than those of the mind consciousness; whether one becomes a Buddha depends entirely on the manas. The manas's operation itself cannot be said to be simple or complex, because the manas's discerning wisdom is poor; the manas cannot introspectively analyze its own operation of contacting mental sense-objects and discerning mental sense-objects. Mental sense-objects are too important; when it cannot discern them clearly itself, it summons the mind consciousness to come out and discern them.