Among the four forms of birth, the nine realms of existence, and the twenty-five kinds of sentient beings, which kind of being do cells belong to?

Cells are the basic structural units composing the life bodies of sentient beings. They are composed of the four great seeds and have no conscious mind, so they are not independent living entities and are not sentient beings. The composition, arising, ceasing, and mutation of the four great seeds are the functions of the tathāgatagarbha; therefore, all the functions of cells are the operating mechanisms of the tathāgatagarbha, and all activities of life are the operating mechanisms of the tathāgatagarbha. This part of the content is especially profound and subtle, extremely difficult to observe—many times harder than observing the activities of the manas. All of this belongs to the domain of the seed-wisdom of Consciousness-Only, including observing the operating mechanisms of the manas, which all require the seed-wisdom of Consciousness-Only. Ordinary people's views of the manas are not derived from contemplative practice (vipaśyanā-caryā) of direct perception, so they are all unreliable, and one must not be too self-confident.

Observing the various activities of cells under a microscope, one will know how fine, subtle, deep, and secret the operating mechanisms of the tathāgatagarbha are, how hard to know and fathom, and how miraculous. How does He construct the life body? How does He make the life body function? How does He make the life body disappear and perish? From this one can know that the entire life body is entirely the function of the tathāgatagarbha; therefore, the life body belongs to the tathāgatagarbha, not to the manas-self. The manas has not the slightest reason to claim the life body as its own, yet it goes on and on, day after day, with "I, I, I" without end, lacking self-awareness and also lacking awareness of others, knowing nothing at all—only because of this does it endlessly afflict itself day after day with "I, I, I." This is the most fundamental beginningless ignorance (avidyā).