Why does the manas use the six consciousnesses?

The six consciousnesses have a great obstructive effect; using the six consciousnesses distracts the manas, preventing concentration, and obstructs the arising of meditative concentration (samādhi) and the power of wisdom (prajñā-bala). Only when the manas has no other choice will it employ the six consciousnesses to serve itself; when the manas itself has the ability to do things personally, it does not use the six consciousnesses. Once the six consciousnesses are used, the manas becomes useless, and its abilities cannot be exercised or developed. In fact, and ultimately, all dharmas are what the manas itself needs, so it is best to let the manas exercise its own functions and roles, relying on the six consciousnesses as little as possible. But ordinary people without meditative concentration cannot do this; only when one cultivates to the stage of an eighth-bhūmi bodhisattva can one completely stop relying on the six consciousnesses and be able to substitute for their functions and roles. When the manas substitutes for the six consciousnesses, this is called the interfunctioning of the six faculties.

Ru Chun: There are several points in the above passage that I do not understand. 1. If the six consciousnesses and the five aggregates (pañca-skandha) have an obstructive effect on the manas, why would the manas want to give rise to them? 2. What situation does "having no other choice" refer to?

Reply: Because the manas alone cannot accomplish things, in most cases it must rely on the six consciousnesses to discern the six sense objects (ṣaḍ-viṣaya), and use the mind consciousness to assist itself in thinking, analyzing, and making decisions. But when the activity of the six consciousnesses becomes great, the manas has no choice but to deal with numerous sense objects and worldly affairs; the mind cannot settle down, and wisdom cannot arise. "Having no other choice" is because—who would want their own affairs to be done by others in their place? It is only because the manas' own energy and abilities are limited that it has to find helpers, but after all, no matter who does it, it is not as good as doing it oneself. Once the six consciousnesses are used, all matters become complicated and mixed, and it is very hard to have meditative concentration. People whose minds are too active find it hard to cultivate concentration; people with rich imagination find it hard to cultivate concentration; people who pay attention to many things find it hard to cultivate concentration; people who like to deliberate (manasikāra) and deliberate a lot find it hard to cultivate concentration. In short, people who are unwilling to withdraw their mind from sense objects find it hard to cultivate concentration.

Lantian: When the manas has heavy ignorance and afflictions, it is difficult for it to judge and handle external matters based on the perceiving-aspect (darśana-bhāga) of the eighth consciousness and the inner object-aspect (nimitta) of the brain's supreme faculty (indriya). Therefore, the manas must give rise to the first six consciousnesses to help analyze and process. But after the six consciousnesses are produced, because the information they receive is broad and mixed, this greatly increases the manas' tendency to seek external objects, further interfering with the manas' focus and affecting its thinking and judgment. Thus the manas has no choice but to rely on the judgments of the six consciousnesses to make decisions, and so the manas' function is weakened. Therefore, only by increasing meditative concentration, subduing afflictions, and reducing external feeling can the manas' function be strengthened.

Ru Chun: Because of one thought of ignorance (avidyā), the manas does not know that it is illusory, and always wants a platform to display itself, so it gives rise to the body of the five aggregates (pañca-skandha) as a prop, feeling that this is "I." After having the body of the five aggregates, it then wants to grasp (upādāna) and discern more dharmas in order to strengthen the self, so it further gives rise to the six consciousnesses to expand its ranks. The six consciousnesses are very obedient to Him, seeking and grasping more dharmas to provide to the manas. As a result, the manas becomes even busier—on one hand it must be mindful of the dharmas given by the eighth consciousness, and on the other hand it must process the dharmas discerned by the six consciousnesses—so its energy and power are even more dispersed. In general, because the manas is too greedy, it ends up doing something that digs its own pit and falls into it itself.