Dharmas Unknown to Consciousness Are Not Equal to Nonexistence

The fact that a dharma cannot be observed by the mind consciousness does not mean that the dharma does not exist, because the mind consciousness is foolish and ignorant. Just as the mind consciousness cannot observe the eighth consciousness, this does not prove that the eighth consciousness does not exist. What mental activities the manas actually engages in during sleep, ordinary people indeed cannot observe. That does not prove that the manas has no mental activities; the Buddha can know any mental activity of the manas at any time.

The extremely numerous mental activities of the manas cannot be observed by the mind consciousness of ordinary people, but that does not mean the manas does not have so many mental activities. In practice, one should make good use of logical thinking. Only by well enhancing one's capacity for logical thinking, together with the deliberation (manasikāra/manana) upon dharmas during meditative concentration (samādhi), can one effectively increase wisdom, continuously eradicate ignorance, observe more and deeper dharmas, and realize more and deeper principles.

The eight consciousnesses—the mind kings—at the Buddha-ground can be observed by no one, and therefore cannot serve as a basis for one's debates. The eight consciousnesses before the Buddha-ground can be observed only in small part by bodhisattvas who have attained the bhūmis, and therefore others also may not take them as a basis for debate. Whatever is not personally observed by oneself may not be used as a basis for debate.