When there is no mind consciousness, can the manas alone discern and deliberate?

The manas has the characteristic of constant, attentive deliberation (manasikāra). "Constant" means frequently, always, forever, without interruption; "attentive" means examining and deliberating; "deliberation" means pondering, measuring, weighing, and contemplating. The fact that the manas has this nature shows that the manas is a decision-maker, one who is in charge, having the final say over all dharmas. So how does this function of the manas operate? It operates through the five universally present mental factors, the five object-specific mental factors, and the wholesome and unwholesome mental factors.

Since the manas is a consciousness that is in charge and has the final say over all dharmas, it must possess considerable judgment in order to be in charge and make decisions. And how does the manas judge, and on what basis does it judge and decide? The manas must rely on its own deliberative nature to judge and decide. If the manas could not deliberate on its own, it would have no way to make its own judgments, no way to decide anything, no way to exercise mastery, and thus it would not be a consciousness that is in charge. When the manas deliberates on its own, it sometimes also relies on information transmitted by the six consciousnesses, depending on the mind consciousness's thinking, analysis, logical reasoning, and so on. But no matter what, once the manas obtains information from the six consciousnesses, it must still personally deliberate and examine it, and make its own judgment.

Sometimes the manas receives a great deal of information during the day and has no time to deliberate on it. Then at night, without the disturbance of the six consciousnesses, it continuously filters and deliberates on that information by itself, and sometimes dreams appear, letting the mind consciousness help out within the dream. If during the night the manas has thought the matter through and reached a conclusion, then the next morning, as soon as one opens one's eyes, the mind consciousness understands it, and may even recall the circumstances in the dream.

It is said that the periodic table of elements was worked out in a dream, and many scientific problems have been solved in dreams. Very often, there are things the mind consciousness cannot figure out, so it stops considering them; yet at some unknown moment, one suddenly understands them. This is the result of the manas's deliberation, solved without the mind consciousness being engaged on its own.

Some scientists, out of love for their scientific research, work day and night, forgetting food and sleep. Even when asleep, they wake up in the middle of the night to continue pondering, or dreams are produced for them to ponder. In all these cases it is the manas that is pondering, deliberating, and investigating, day and night without distinction, keeping the matter constantly in mind. This is the manas applying effort — it is the manas's diligence.

If the manas's mental factors were incomplete or not fully endowed, it simply could not accomplish so many things, produce so many inventions and creations, or investigate so many profound questions. Without fully endowed mental factors, it would be powerless to do so.