The mind consciousness serves the manas

Question: Regarding the doctrine of the mind consciousness being the master, as the Verses on the Structure of the Eight Consciousnesses say, "In moving the body and producing speech, it alone is supreme," as well as deliberating thought (śintana), determining thought, and motivating thought—are these all speaking of the mind consciousness being the master?

Answer: None of these say that the mind consciousness is the master. The meaning of "moving the body and producing speech" is that the mind consciousness can, together with the body consciousness, move the body and create bodily karma, and the mind consciousness can, together with the body consciousness, produce vocal sounds and create verbal karma. For bodily and verbal karma, the mind consciousness has the greatest function and plays the primary role, while the body consciousness serves as an auxiliary with a weaker function.

Deliberating thought, determining thought, and motivating thought—these describe the mental factor of volition (cetanā) of the mind consciousness. Although the mind consciousness has these functions of the volition mental factor and can make decisions, whether its decisions ultimately have their intended effect still depends on whether the manas accepts them and the degree to which it accepts them. For example, a child decides to buy a toy; whether the purchase can ultimately be made depends on whether his parents agree, because the money is controlled by the parents, and the parents have the decision-making power over spending. For instance, a staff officer or subordinate decides to launch a military exercise, but whether this matter is ultimately carried out is decided by the chief and the commander-in-chief; the staff officer or subordinate merely offers a suggestion, and whether it is heeded is up to the leadership.

The mind consciousness exists to serve the manas. If the manas does not need the mind consciousness's service, it will not decide to give rise to the mind consciousness, and then there will be no appearance of the mind consciousness, so there can be no talk of it being the master or making decisions. The five sense consciousnesses also have the volition mental factor and can make decisions, but the decisions of the five sense consciousnesses are even weaker than those of the mind consciousness; whether they count or are heeded all rests with the manas. Then, after the manas has made the decision as master, whether the matter can be accomplished still depends on the eighth consciousness; if there are no karmic seeds and no merit, the eighth consciousness is also powerless. Therefore, for the manas to be the master and accomplish things and give rise to certain dharmas, there are also preconditions; it is not that whatever the manas wants to do, it can accomplish.