An Explanation of the Pure Dharmadhātu and the Four Wisdoms

The Buddha-bhūmi Sūtra says: 有五种法摄大觉地，所谓清净法界、大圆镜智、平等性智、妙观察智、成所作智。What is the relationship between the pure dharma realm and the four wisdoms that follow?

After attaining buddhahood, the four wisdoms are perfectly luminous. First, the sixth and seventh consciousnesses undergo the third transformation of consciousness into wisdom; the five sense consciousnesses undergo the first and also the last transformation of consciousness into wisdom; and the eighth consciousness undergoes the first and also the last transformation of consciousness into wisdom. The mind consciousness is transformed into the wisdom of wonderful observation, the seventh consciousness (manas) into the wisdom of equality, the five sense consciousnesses into the wisdom of accomplishing what is to be done, and the eighth consciousness into the great mirror-like wisdom (ādarśa-jñāna). First, the mind consciousness is transformed from consciousness into wisdom: the defiled mind that originally possessed ignorance and afflictions is transformed into the wisdom of wonderful observation, which is no longer obscured by afflictions. When there is defilement by afflictions, there is obstruction, which hinders the arising of wisdom; the power of observation is coarse and not subtle, and the wisdom is shallow.

If the mind consciousness's power of observation is shallow and not subtle, it cannot convey the profound ultimate reality of all dharmas to the manas for the manas to know; the manas's view of a self in dharmas cannot then be eradicated, and as long as there is a self in the mind, there is no wisdom of equality. Therefore, only when the mind consciousness first eradicates the afflictions and possesses the wisdom of wonderful observation can the manas be enabled to eradicate the afflictions and realize a certain degree of the selflessness of dharmas, thereby attaining the wisdom of equality—observing that sentient beings are equal to and identical with oneself, equal to and identical with the Buddha, seeing no distinction of high or low among dharmas.

When the sixth and seventh consciousnesses undergo the third transformation of consciousness into wisdom, the transformation is ultimate and complete: ignorance is exhausted. The five sense consciousnesses are transformed into the wisdom of accomplishing what is to be done, accomplishing all dharmas; the ignorance and defilement of the seven consciousnesses stored within the eighth consciousness are ultimately and completely exhausted, and it is transformed into the great mirror-like wisdom (ādarśa-jñāna). At this point, the metamorphosis is complete: a sentient being of the causal stage is transformed into a Buddha of the fruition stage.

Because the great mirror-like wisdom (ādarśa-jñāna) no longer contains karmic seeds of ignorance and defilement, the entire mind-ground of the eighth consciousness is utterly and supremely pure, and all dharmas born from this pure mind—everything in the dharma realm—are pure. The six faculties, six sense objects, six consciousnesses, the Buddha-land, and the material world are all purified along with the pure mind, without a trace of defilement. "As the mind is purified, the Buddha-land is pure"—this is precisely the principle.