The Nature of the Eight Consciousnesses Dharmas Is Profound and Subtle

Consciousness-seeds arise and cease moment by moment. In five states—dreamless sleep, coma, the moment of death, the attainment of the Unconsciousness Samādhi (Asaṃjñī-samāpatti), and the attainment of the Cessation Samādhi (Nirodha-samāpatti)—the six consciousnesses inevitably cease and vanish. Therefore, the conscious mind is characterized by arising and ceasing, change and alteration; it is impermanent, suffering, empty, and without self. As long as the seventh consciousness exists and functions, the eighth consciousness follows it, much like an attendant follows its master. The natures of these two consciousnesses are vastly different yet intimately connected. The eighth consciousness is the most subtle and profound; next, the seventh consciousness is also subtle and profound; then the sixth consciousness is subtle and profound; and finally, the five sense consciousnesses are subtle and profound. All eight consciousness-kings are subtle and profound. When the natures of all eight consciousnesses are exhaustively known without remainder, sentient beings attain Buddhahood.

In the Sphere of Neither Perception Nor Non-Perception (Nevasaṃjñānāsaṃjñāyatana), the sixth consciousness becomes extremely subtle; the higher the level of samādhi, the more subtle the mind-consciousness becomes, and its discerning faculty weakens accordingly. The Sphere of Neither Perception Nor Non-Perception represents the highest mundane samādhi within the three realms. When consciousness enters samādhi there, this mind-consciousness lacks the self-verifying part (svasaṃvitti-bhāga) and cannot introspectively observe its own existence; that is, it does not know that it exists. In other samādhi states, the mind-consciousness can still introspect upon itself and know its own existence. In the samādhi of the First Dhyāna and the samādhi of the Desire Realm, the mind-consciousness can still discern the mental objects (dharmas) arising from the five sense objects. In the samādhi of the Second Dhyāna and above, the mind-consciousness can no longer discern the mental objects arising from the five sense objects because the first five consciousnesses have already ceased; the mind-consciousness cannot independently discern the five sense objects. Therefore, it is said that consciousness is characterized by arising and ceasing, change and alteration; it is not real and eternal, thus it is without self. The five sense consciousnesses are likewise, and the seventh consciousness is also likewise.