Why Can Manas and Consciousness Communicate Intentions with Each Other?

For example, when the manas (mental faculty) desires to eat, the tathāgatagarbha (Buddha-nature) complies with the intention of manas and gives rise to consciousness (mano-vijñāna). Manas then communicates to consciousness to discern the various dishes before it, selecting those it prefers to eat. Consciousness can grasp the thoughts of manas, and after consciousness discerns, manas can also comprehend the thoughts of consciousness; the two can communicate instantaneously. However, when manas discerns dharmas (phenomena) from past lives and communicates them to consciousness, consciousness fails to grasp them or comprehends only a little. Why is this? Because consciousness has not experienced past lives and thus has no memory of them, rendering it incapable of discernment.

Manas determines to discern the various dishes to decide which to eat, and consciousness arises to perform this discernment on behalf of manas. After consciousness discerns and judges the characteristics of each dish, it communicates this to manas. Once manas comprehends, it decides what to eat. It is also possible that consciousness, merely by observing together with the visual consciousness, cannot discern comprehensively. Thus, manas decides to taste some of the food, whereupon the tongue consciousness and nose consciousness jointly participate in discernment and judgment. After manas comprehends, it knows which dish is delicious and to its liking, and thus eats heartily, while ignoring the unpalatable ones.

These dishes can be directly contacted by consciousness and the five sense consciousnesses together, hence there are sensations, perceptions, and thoughts, enabling judgment. Regarding dharmas from past lives, without supernatural powers (abhijñā), the five sense consciousnesses cannot contact them at all. Consciousness lacks mind-reading ability, lacks experience, and possesses insufficient wisdom; thus, it cannot know the thoughts and contemplations within manas. If consciousness possesses great wisdom, it can clearly discern the dharmas contemplated and implied within manas.

Why can consciousness and manas communicate their intentions to each other? Because manas contacts mental objects (dharmas), giving rise to consciousness. The three (manas, mental objects, and consciousness) then combine in contact. Regarding mental objects, not only can manas discern them, but consciousness can also discern them, differing only in the degree and clarity of discernment. Throughout this process, consciousness and manas also remain in constant contact, mind touching mind. Naturally, they can mutually know each other's intentions, with the difference lying in the degree of knowing—varying in depth and scope. As long as consciousness exists, it is necessarily in contact with manas. Therefore, their respective intentions can be transmitted and exchanged at any time and place. If the exchange is poor, the mind becomes troubled; if the exchange flows smoothly, the mood becomes pleasant. This bears some resemblance to the relationship between two individuals interacting.