Is the wisdom of knowing through the mind consciousness alone deliberating, analyzing, understanding, and inferring dharmas a direct perception (valid direct cognition)?

Conclusions reached through the mind consciousness's thinking and inference are not realized through practice, not personally attained; without genuine, usable evidence to support them, the doubts within the mind are not eliminated. When at some point one encounters facts that contradict them, one will regret and overturn one's former conclusions. Moreover, the deep-seated doubt within the manas cannot be discovered at all when the mind consciousness lacks wisdom. Therefore, the mind consciousness's inferences cannot eliminate doubt and cannot inspire faith in the manas, and thus they have no practical use and no benefit to be experienced.

Even if the result of an inference is completely correct, one hundred percent correct, it is still erroneous cognition (non-valid cognition). Why? For example, suppose you infer that I must have stolen your things, and in fact I really did steal them. But since you did not see it with your own eyes or catch me with your own hands, your inference is useless; the court will not convict and sentence me based on your inference or anyone's inference. Even if I myself admit that I stole, if I cannot produce strong evidence proving that I stole, the court still cannot pronounce a verdict. Some people, in order to exonerate those with whom they have karmic affinity from their sins, are willing to take the punishment in their place; but without genuine, convincing evidence, even if they go to court to confess, admitting that the sin was personally committed by themselves and had nothing to do with others, the court still cannot convict and sentence based on one side's word alone.

In the Buddha's Dharma, when one lacks meditative concentration (samādhi), even if in the activities of the five aggregates and eighteen realms one infers the existence of the eighth consciousness, imagining that the eighth consciousness has a certain function, certain functions—because there is no personal realization or attainment, such inference has no benefit of merit to be experienced and will change nothing. The self-view (ātma-dṛṣṭi) still remains, the three fetters still bind oneself, and one cannot escape the retribution of the three evil destinies at the end of life. You may be allowed to have inferred the eighth consciousness correctly; you may be allowed to imagine fifty or sixty percent, sixty or seventy percent, seventy or eighty percent of it, but still no great wisdom will arise, there will still be no state of meditative absorption (samādhi), still no benefit of merit to be experienced, and one is still an ordinary being (pṛthagjana). One will never, through such imagination and inference, eliminate ignorance and afflictions.

The methods and means of practice used by the patriarchs through the ages, the paths they walked, are absolutely correct, accord with valid direct cognition, and their attainments are genuine and credible, exerting an enormous positive influence and impetus upon Buddhism. The patriarchs' teachings all reveal the truth of practice and realization, and are all true knowledge born of actual practice. Sentient beings of later generations, due to meager merit (alpa-puṇya) and deep obstructions, are unable to devote body and mind to diligent practice as the patriarchs did; mostly it is a mentality of opportunism and cutting corners at work—they all want to take shortcuts. Practice means abandoning the self, regardless of all cost; where is there any shortcut to take? One step less walked means one portion less of merit gained, one portion less of bodily and mental experience, one portion more of loss suffered—in fact, this is a practice of first deceiving oneself and then deceiving others. If there were a shortcut to take, would the Buddha not have told us and guided us? Sentient beings suffer so much—would the Buddha not wish for sentient beings to attain the Buddha-way as quickly as possible and avoid detours?

Any practice that does not accord with the Buddha's teachings, any practice that violates the Buddha's original intent and harms the interests of sentient beings, will in the end be destroyed and expelled from Buddhism; it is only a matter of sooner or later.