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

Tathāgatagarbha is the essence of the mind, the subject, the sovereign. The five universal mental factors (caittas) are subordinate, the objects, existing dependent upon Tathāgatagarbha, the followers. Where the sovereign goes, the followers necessarily arrive. Tathāgatagarbha is that which relies, while the mental factors are that upon which reliance is placed; the distinction between master and subordinate is clear. Just as for 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 follower—wherever the "I" of the five aggregates appears, the body necessarily follows and arrives. The relationship between the five universal mental factors and Tathāgatagarbha is one layer more intimate and inseparable than the relationship between Buddha-nature and Tathāgatagarbha. While Buddha-nature may have instances of separation, the five universal mental factors never have moments of separation. Where there is Tathāgatagarbha, there are necessarily mental factors operating alongside it; the mental factors and the conscious mind are inseparable. This is the same principle as having a cart necessarily means having wheels, or having a person necessarily means having a body.

The "seeing" of the mental factors and the "seeing nature" of Buddha-nature are two different modes of seeing, with distinct functions and roles. Buddha-nature is Buddha-nature, and the mental factors are the mental factors; these two cooperate with Tathāgatagarbha from different aspects to perceive all dharmas and operate all dharmas. The seeing of Buddha-nature requires certain conditions, such as light and darkness. In the state of Nirvana, there are no appearances of light and darkness, birth and death, nor are there deluded dharmas; therefore, Buddha-nature does not function. In contrast, the operation of the mental factors has no conditions whatsoever; it never ceases, is eternally functioning, and never departs from Tathāgatagarbha. Where there is Tathāgatagarbha, there are necessarily mental factors.