Understanding Cannot Replace Personal Realization

All dharmas of the five aggregates and eighteen realms are the nature of the tathāgatagarbha. This principle can only be gradually comprehended through contemplative practice (vipaśyanā-caryā) after personally realizing the tathāgatagarbha. If one merely relies on the mind consciousness to imagine that there is a tathāgatagarbha performing some function or certain functions, then there is no way to directly observe the operation of the tathāgatagarbha, and no way to observe the tathāgatagarbha nature of the five aggregates and eighteen realms. Understanding is, after all, merely understanding; imagination is, after all, merely imagination—neither can substitute for personal realization.

How the tathāgatagarbha records and stores seeds, and how it realizes cause and effect—these belong to the domain of the seed-wisdom of Consciousness-Only (唯识种智), and only bodhisattvas who have attained the bhūmis are capable of observing them through direct perception/valid direct cognition. The seed functions of the tathāgatagarbha, its function of manifesting the myriad phenomena of the world, as well as the functions of all the seeds of the tathāgatagarbha, all belong to the domain of the seed-wisdom of Consciousness-Only, and only bodhisattvas who have attained the bhūmis can observe them through direct perception. Pre‑bhūmi bodhisattvas (pūrvabhūmika bodhisattva), because their afflictions are heavy and their meditative concentration (samādhi) is insufficient, lack adequate wisdom; moreover, the sixth and seventh consciousnesses have not undergone the transformation of consciousness into wisdom, so they are powerless to observe these extremely profound and secret meanings of the Dharma. Therefore, what is merely understood cannot substitute for direct observation.