The Relationship Between Mental Factors, Buddha-Nature, and Tathāgatagarbha

The Tathāgatagarbha is the substance of the mind, the subject, the sovereign. The five universal mental factors are subordinate, the object, existing dependently upon the Tathāgatagarbha; they are the attendants. Where the sovereign goes, the attendants must follow. The Tathāgatagarbha is that which relies, the mental factors are that which is relied upon; the distinction between master and subordinate is clear. It is like sentient beings in the desire realm: the five aggregates or the seven consciousnesses are the master, or the mental faculty (manas) is the master, and the body is the subordinate. Where the self of the five aggregates appears, the body must follow and arrive there. The relationship between the five universal mental factors and the Tathāgatagarbha is even closer and more inseparable than the relationship between the Buddha-nature and the Tathāgatagarbha. There are times when the Buddha-nature may be considered separately, but there are no times when the five universal mental factors are separate. Where there is Tathāgatagarbha, there are necessarily mental factors operating alongside it; the mental factors and the conscious mind are inseparable. It is the same principle as having a cart necessarily meaning it has wheels, or having a person necessarily meaning they have a body.

The "seeing" of the mental factors and the "seeing nature" of the Buddha-nature are two different modes of seeing, with different functions and roles. The Buddha-nature is the Buddha-nature, and the mental factors are the mental factors; these two cooperate with the Tathāgatagarbha from different aspects to perceive all dharmas and operate all dharmas. The seeing of the Buddha-nature requires certain conditions, such as light and darkness. In the state of Nirvāṇa, there are no appearances of light and darkness or arising and ceasing, nor are there false dharmas; therefore, the Buddha-nature does not function. However, the operation of the mental factors has no conditions whatsoever; they never cease, are perpetually functioning, and never depart from the Tathāgatagarbha. Where there is Tathāgatagarbha, there are necessarily mental factors.