An Exposition of the Pure Dharmadhatu and the Four Wisdoms

The Buddhabhūmi Sūtra states: There are five dharmas that encompass the ground of great enlightenment. They are: the dharmadhātu of purity, the great perfect mirror wisdom, the wisdom of equality, the marvelous observing wisdom, and the wisdom of accomplishing what is to be done. What is the relationship between the dharmadhātu of purity and the subsequent four wisdoms?

After attaining Buddhahood, the four wisdoms are perfectly luminous. First, the sixth and seventh consciousnesses undergo the third transformation from consciousness into wisdom. The five sense consciousnesses undergo their first and final transformation from consciousness into wisdom. The eighth consciousness undergoes its first and final transformation from consciousness into wisdom. The mental consciousness (mano-vijñāna) transforms into the marvelous observing wisdom. The seventh consciousness (manas) transforms into the wisdom of equality. The five sense consciousnesses transform into the wisdom of accomplishing what is to be done. The eighth consciousness (ālaya-vijñāna) transforms into the great perfect mirror wisdom.

First, the mental consciousness transforms from consciousness into wisdom. It changes from its original state as a defiled mind possessing ignorance and afflictions into the marvelous observing wisdom, which is free from the obscurations of afflictions. Where there are afflictions and defilements, there are obscurations that hinder the arising of wisdom; the power of observation becomes coarse, not subtle, and wisdom becomes shallow.

If the mental consciousness's power of observation is shallow and not subtle, it is unable to convey the profound true reality of all dharmas to the mental faculty (manas) to enable the mental faculty to know it. Consequently, the mental faculty's view of a self in dharmas cannot be eradicated. Where there is a sense of self in the mind, there is no wisdom of equality. Therefore, only when the mental consciousness first eradicates afflictions and possesses the marvelous observing wisdom can it enable the mental faculty to eradicate afflictions, realize a certain degree of selflessness of dharmas, and thereby attain the wisdom of equality. This wisdom perceives sentient beings and oneself as equal and identical, and perceives oneself and the Buddha as equal and identical, seeing no distinction of high or low in dharmas.

The third transformation of the sixth and seventh consciousnesses from consciousness into wisdom is ultimate and complete. Ignorance is utterly exhausted. The five sense consciousnesses transform into the wisdom of accomplishing what is to be done, accomplishing all dharmas. The ignorance and defilements of the seventh consciousness stored within the eighth consciousness are completely and ultimately eradicated, transforming it into the great perfect mirror wisdom. At this point, the metamorphosis is complete, transforming from a sentient being on the causal ground into a Buddha on the resultant ground.

Since there is no longer any seed of ignorance, defilement, or karma within the great perfect mirror wisdom, the entire mind-ground of the eight consciousnesses is supremely pure. All dharmadhātus born from this pure mind are pure: the six sense faculties, the six sense objects, the six consciousnesses, the Buddha-lands, and the material world — all become pure in accordance with the pure mind, without a trace of defilement. The principle "where the mind is pure, the Buddha-land is pure" is precisely this meaning.