The manas is a non-material faculty, not a material faculty.

The eighteen dhātus include the six faculties, the six sense objects, and the six consciousnesses. The six faculties include the eye, ear, nose, tongue, body, and mind faculties. Among these, the first five faculties are composed of the four great seeds of earth, water, fire, and wind. The gross faculties (saṃsthāna-indriya) are on the surface of the body; sentient beings can see, touch, and contact them with the naked eye, they can be damaged and altered, and they exhibit arising-and-ceasing phenomena visible to the naked eye. The supreme faculties (indriya) of the five faculties are located at the back of the brain; they can be seen through surgery, and they too are material form that can be seen, touched, and contacted, capable of being damaged and altered, being conditioned dharmas of suffering that arise and cease and are impermanent. When the five faculties are damaged, the functions of the material body are obstructed and abandoned, resulting in a vegetative state or even death.

The manas, however, is not composed of the four great seeds of earth, water, fire, and wind; it is formed from consciousness seeds. Therefore it is not material form but a mental dharma, possessing the functions of a conscious mind. Material form is a dharma born of causes and conditions; it has no autonomy and is passively born and manifested through the conjunction of the tathāgatagarbha and the manas. It cannot do without the driving force of the manas; if the manas does not drive it, material form vanishes immediately. The manas, however, was not born later; it has coexisted with the tathāgatagarbha since beginningless kalpas, sustained continuously by the consciousness seeds provided by the tathāgatagarbha, requiring no other causes and conditions, and is not a dharma born of causes and conditions. As long as the manas has anything to be attached to, it will not perish but continue to exist, and the world of the five aggregates will likewise continue to arise and cease without end. Although the five aggregates and five faculties arise and cease incessantly, the manas never perishes; no one can destroy the manas, except when arhats and pratyekabuddhas enter nirvāṇa. The mental dharma of the mind faculty, which has no material form, differs enormously in function from the five faculties that have material form. The five faculties have no capacity for recognition, no mental concomitants (caittas), no defiled or pure nature; they can be influenced by the manas, and their function of receiving the five sense objects is directed by the manas, but they cannot direct the five sense objects or the five consciousnesses, much less direct the manas, though they can influence the manas's feeling and decision-making functions.

The functional power of the manas as a mental dharma is extremely formidable. It has the role of presiding over and making decisions for the body of the five aggregates, dominating the arising, alteration, and eventual perishing of all worldly dharmas. It has the functions of mental concomitants of a conscious mind; it has both defilement and purity; it has recognition, discernment, judgment, and decision-making capacity; it has the tendency to seek benefit and avoid harm; it has both self-nature and selflessness; it has both foolishness and wisdom; it has habitual tendencies, habits, and afflictions; it has the imputed nature (parikalpita-svabhāva); it can determine sentient beings' saṃsāra of birth and death, determine their turning toward nirvāṇa and the accomplishment of the buddha path—above in the heavens and below on earth, the manas is the sovereign. The five faculties, being material form, lack these characteristics; only the manas, a mental dharma, possesses them. Therefore the manas is a mental dharma, not material form; it is a formless faculty. A "faculty" (indriya) has the meaning of giving rise to a conscious mind, but this so-called arising is not direct generation; rather, it can lead to the arising of the six consciousnesses, being the most immediate condition for their arising. What directly gives birth to the six consciousnesses is the tathāgatagarbha, which, borrowing karmic conditions and the six faculties, gives rise to the six consciousnesses. But if the manas has no mind toward any dharma, the tathāgatagarbha cannot give rise to the six consciousnesses. Thus the condition for the arising of the five faculties is very passive, whereas the condition for the arising of the manas is extremely active and proactive; its driving force for giving rise to the six consciousnesses and all dharmas is immensely powerful, and it also determines whether the five faculties arise or not. Such autonomous, powerful driving force can only be possessed by a formless mental dharma, not by the five faculties that have material form. Therefore the manas is a mental dharma, not material form; it is a formless faculty, not a faculty with material form.