Samyutta Nikāya, Sutta 289, Part 2

(2) However, ignorant and unlearned ordinary beings cannot develop disgust toward the mind-consciousness, cannot renounce desire for it, nor relinquish it. What is the root cause? It is because sentient beings delight in clinging to the functions of consciousness, which appear vivid and alluring, thus they ceaselessly grasp and appropriate them as their own. All functional activities of the physical body arise precisely because of consciousness. For instance, walking, standing, sitting, and lying down cannot occur without body-consciousness; these are functions arising from the body-consciousness. Life activities are inseparable from these functions of movement and rest, hence sentient beings cling to them. With body-consciousness, there is movement; with eye-consciousness, there is seeing; with ear-consciousness, there is hearing; with nose-consciousness, there is smelling; with mind-consciousness, there is thinking, discrimination, analysis, judgment, reasoning, and generating deluded thoughts. The various consciousnesses cooperate to produce manifold functions; the mind-consciousness and the first five consciousnesses engage in discrimination and function together. These functions feel utterly real, vivid, and lifelike—this is perceived as "me" and "mine," leading to relentless attachment.

It is not easy to realize that the mind-consciousness is not the self. Clearly, there seems to be an "I" that knows all phenomena; it feels very real—"I" am indeed sitting here listening to the Dharma; "my" eyes see forms, indeed perceiving all material objects contacted; "I" truly hear sounds. One does not regard the functions of seeing, hearing, sensing, and knowing by the eyes, ears, nose, tongue, and body as illusory, and thus clings to them tightly. Even less can one acknowledge the various functions of the mind-consciousness as illusory, feeling that consciousness truly can think, generate delusions, reason, and plan. Therefore, sentient beings cannot perceive the mind-consciousness as illusory. Yet, without overcoming this obstacle, one cannot attain any fruit of enlightenment, great or small.

Thus, the Buddha said: Ignorant and unlearned ordinary beings can develop disgust toward our physical body composed of the four great elements, can renounce desire for it, and can relinquish it. But we cannot renounce desire for our own mind-consciousness, cannot develop disgust toward it, cannot relinquish it. In all matters, we must follow our own mind; in all actions, we must act according to our own will. We cannot renounce desire for our own mind; we cherish our mind because this mind-consciousness indeed possesses these functional capacities.

Life after life, throughout the long night of birth and death, sentient beings protect and cherish what they cling to as "me," always acting according to their own will, cherishing themselves, safeguarding their own mind-consciousness. Whatever I obtain, whatever I wish to possess, whatever I seek to claim—all are the will of this mind-consciousness. They take the functions and capacities of this mind-consciousness as the self, as a truly existing, eternally indestructible "I." In reality, the mind-consciousness ceases under several circumstances. For example, while listening to the Dharma, you might fall asleep, unaware of what is said afterward—at that time, the mind-consciousness ceases. When you sleep without dreams, the six consciousnesses also cease then. After you wake up, these consciousnesses reappear. They cease and arise; they are capable of arising and ceasing. The mind-consciousness is constantly changing in the process of arising and cessation.

The functional capacities of our eighth consciousness, however, always exist just like that, unchanging. They do not rely on external conditions; its functions and capacities remain unaltered. The eighth consciousness always produces all phenomena, manifests all dharmas; nothing can obstruct it. That is the true reality. Whether you are in deep meditation or asleep, regardless of the circumstance, it always exists, always possesses its functional nature and capacities. The first six consciousnesses are not like this; they are always arising and ceasing, constantly changing.