Understanding Cannot Replace Realization

All dharmas, including the five aggregates and eighteen elements, are of the Tathagatagarbha nature. This principle requires realization of the Tathagatagarbha through direct experience, followed by contemplative practice, to gradually attain thorough comprehension. Merely imagining with the conscious mind that there exists a Tathagatagarbha performing some function or functions makes it impossible to directly observe the operation of the Tathagatagarbha or to perceive the Tathagatagarbha nature inherent in the five aggregates and eighteen elements. Understanding remains understanding, and imagination remains imagination; neither can substitute for genuine realization.

How the Tathagatagarbha records and stores seeds, and how it actualizes cause and effect, all belong to the scope of the wisdom of consciousness-only (vijñapti-mātratā-jñāna), which only Bodhisattvas on the bhūmis (stages of realization) have the capacity to observe directly through perception (pratyakṣa). The seed-functioning of the Tathagatagarbha, its functioning in manifesting all phenomena of the world, and the functioning of all the seeds within the Tathagatagarbha, all fall within the scope of the wisdom of consciousness-only. Only Bodhisattvas on the bhūmis can observe these directly. Bodhisattvas below the bhūmis, due to heavy afflictions (kleśa) and insufficient meditative concentration (dhyāna), lack sufficient wisdom. Having not transformed the sixth and seventh consciousnesses into wisdom, they are unable to observe these extremely profound and subtle Dharma principles. Therefore, intellectual understanding cannot replace direct perception.