Mind-Consciousness Thinking and Manas Deliberation

Question: Is the conclusion that 1+1 equals 2 derived through thinking with the mind consciousness, or through the deliberation (manasikāra) of the manas? 

Answer: As for 1+1=2, if you are very confident about it, with sound reasoning and evidence, and you know the underlying principle, then it is a conclusion reached by the manas. If you can arrive at 1+1=2 but do not know what the underlying principle is, and cannot explain it clearly—you just know this is the conclusion—then it is a conclusion reached by the mind consciousness based on theories it has learned, which is more or less like rote memorization. Otherwise, why would scientists still need to investigate deeply why 1+1 equals 2? 

Of all the knowledge we have learned from elementary school through university, how much of it has actually been verified through personal realization? Although we passed every exam, perhaps even scoring one hundred points, what exams test is the understanding and memorization of knowledge, the amount of knowledge one has mastered; very little of it tests personal realization. Only laboratory work involves verification through realization. Only after entering society does verification through realization come into play, which is why many top students often fail to adapt well after entering society, unable to keep up with its pace and unable to apply what they have learned. 

What is worked out solely through the mind consciousness's thinking and analysis cannot eradicate doubt; when conditions arise, doubts will multiply, and one will no longer trust one's former conclusions. Therefore, conclusions reached through the mind consciousness's thinking and analysis are not firm. When the master has doubts, the master makes the decisions; when the master has his own views, at critical moments he will reject and discard the assistant's conclusions. This is precisely why many people who have realized the fruit and seen the mind through the mind consciousness keep regressing. The mind consciousness's thinking and analysis can proceed without the support of meditative concentration (samādhi), and can occur in a state of scattered mind; but the more meditative concentration there is, the more refined, accurate, precise, and accordant with reality the mind consciousness's thinking becomes. However, no matter how refined, accurate, and accordant with reality it is, it is still not a conclusion reached by the manas itself, so it is not called personal realization; it lacks the virtue of eradication, brings no real benefit, and cannot withstand birth and death. 

The thinking of the mind consciousness can usually be perceived and observed by the mind consciousness itself and can be discovered by it; compared with the manas's deliberation, it is shallower and coarser. The manas's deliberation is deeper and more hidden, not easily discovered, yet it continues thought after thought without interruption. Only when doubt is very deep will the manas deliberate in order to resolve the doubt. This involves meditative concentration: when there is continuity thought after thought, there is meditative concentration. Being able to remain settled on the investigation of the doubt is concentration. No matter when, no matter what one is doing, whether awake or asleep, the question remains in the mind; if one cannot figure it out, one may even become agitated, unable to eat or sleep well, as if one had lost one's soul. When the mind consciousness is coarse, it has no awareness or perception of the manas's deliberation and cannot detect it; it cannot discover the affairs within its own mind, does not know what it truly wants or what it wants to do, and cannot master its own thoughts. This is why so many people cannot discover the manas, do not understand it, cannot master it, and cannot observe it. To deliberate with the manas, one must have meditative concentration—the deeper the better. It is best to eliminate the interference of other miscellaneous affairs; ideally, the six consciousnesses should also not disturb the manas, but simply cooperate with it, gently and subtly cognizing, without provoking scattered thoughts in the manas.