The mental factors (caittas) of the manas are the guiding principle of actual practice, and also the operating system of actual practice.

The mental factors of the manas are the guiding principle of actual practice, and also the operating system of actual practice. "Guiding" means that the mental factors can point toward the goal of one's own cultivation; "principle" means that the cultivation comes down to the transformation of mental actions and mental factors, as well as the transformation of karmic seeds, so that one's mental actions become pure. The operating system means following the mental factors and continually transforming them; actual practice is precisely the process of operating the mental factors, or of the mental factors being operated upon.

The fundamental cause for the change of mental factors is the tathāgatagarbha, but the tathāgatagarbha is not the master consciousness; it has no subjective initiative, does not make decisions, and is passively employed by the manas. Although the arising of all things is produced by the tathāgatagarbha, the driving force is the mental factors of the manas. If the manas does not wish to do anything, the tathāgatagarbha does nothing, and no dharma whatsoever arises.

The manas has subjective initiative; it is the transformation of the manas's mental disposition that prompts the change of karmic seeds. The transformation of the manas's mental factors is the cause, and the change of karmic seeds is the effect. Karmic seeds are formed after the manas wishes to do something and the tathāgatagarbha cooperates by producing the six consciousnesses to carry out the actions. Otherwise, there would be no karmic seeds. Of course, in actual genuine practice, every step causes changes in the manas's mental factors, and the change of mental factors is the effect. The cause is still the manas's mental factors prompting changes in its own mental factors, with the precondition being that the mind consciousness's mental factors push the manas's mental factors.

However, the arising of many dharmas is not driven by the mind consciousness, but is driven entirely by the manas alone. For example, before the five aggregates subject to feeling have arisen, there is no mind consciousness; it is the manas that prompts the tathāgatagarbha to produce the universe, the material environment for existence, and then to produce the body of the five aggregates, and only then does the mind consciousness exist, and only then are there the actions of the five aggregates and the appearance of karmic seeds. Before waking up from sleep, there is no mind consciousness; it is because the manas wishes to wake up that one can wake up afterward. During a coma, there is no mind consciousness; it is because the manas wishes to wake up according to the state of the body that one wakes up afterward. In the mother's womb, at first there is no mind consciousness; it is the manas that wishes to enter the womb and so enters the womb, wishes to dwell in the womb and so dwells in the womb, and wishes to be born and so is born.