The manas's mode of deliberation (manana) is hidden and profound

As for the aspects that the mind consciousness has already discerned, there is no need to think about them further; the manas needs to deliberate (manana) on them silently by itself. The manas's mode of deliberation is very special, different from the thinking of the mind consciousness. What is meant by "special" is that the deliberative nature and mode of deliberation of the manas are extremely difficult for the mind consciousness to observe, so many people simply deny that the manas has any thinking or cognitive activity, denying that the manas has any mental activity at all. These people are far too reckless and hasty, far too self-assured.

When there is no speech and the mind is silent, the mind consciousness has ceased thinking, while the manas is working, never having stopped. The mind consciousness can frequently cease its thinking activity and enter states of rest and sleep, but the manas never rests; it continuously and uninterruptedly ponders and deliberates on all kinds of issues, in a very hidden manner. When the manas deliberates, it is extremely deep and difficult to observe; it can consume the brain's energy and cause neural fluctuations in brain waves.

Therefore, when a person is not speaking or analyzing, we must never assume that this person has no thoughts, no views, no ideas, that their mental activity has stopped and all is quiet. It is not so. Their manas is rapidly turning and operating, deliberating, weighing, and verifying, very deeply and very covertly. Afterwards, a definite resolution arises in their mind—they have an idea, a position, a decision—but they do not necessarily speak it out, do not necessarily express it, do not necessarily let others know. Yet the mind has indeed gained strength; the attitude becomes resolute, even unshakable.

Whereas when the mind consciousness, through thinking, analysis, and reflection, arrives at a result and a decision, the mind is not very firm; there is still hesitation and indecision, unable to make up one's mind. Because the manas does not know or understand, there must be doubt in the mind, and naturally one cannot make up one's mind.