Why Is the Manas Called a Transforming Consciousness (pravṛtti-vijñāna)?

Precisely because the manas is extremely nimble, it is called the transformative consciousness. The meaning of "transformative consciousness" is this: dharmas that did not originally exist—dharmas within the tathāgatagarbha—are, due to the manas's tendency to cling and engage, brought forth and transformed out by the manas. This is the function of the manas as the transformative consciousness. If the manas possesses great wisdom and knows the true reality of the dharmadhātu, relying on the eighth consciousness and relying on true reality, then the manas knows that all dharmas are entirely illusory. When the mind is still and unmoving, some dharmas of the three realms no longer manifest and are no longer transformed out; if the manas does not transform them, the dharmas of the three realms do not appear. The manas transforms out the dharmas of the three realms and transforms out the six consciousnesses—this is what it means to be the transformative consciousness. Transforming the dharmas of the three realms out of the great ocean of the tathāgatagarbha—this is the nature of the transformative consciousness.

When we are in meditative concentration, the manas is still transforming. When we sleep and the aware mind ceases, the manas continues to transform without interruption. Since the manas can transform continuously and unceasingly, transforming out all dharmas, this shows that the manas is in fact extremely nimble. Moreover, whether one has entered the samādhi of no perception, entered the attainment of cessation, or is in the state of dying or in a state of unconsciousness, He continues to operate without interruption—hence He is called the transformative consciousness. Outside of meditative concentration the manas is the transformative consciousness, and within meditative concentration it is also the transformative consciousness; there is not a moment when it is not transforming. Even when asleep, the manas continues to operate unceasingly; even upon entering the samādhi of no perception or the attainment of cessation, it is still transforming. It transforms at every moment, instant after instant, without ever pausing for a single instant. If the manas did not transform, there would be nirvāṇa without remainder.

That is to say, owing to the movement of the manas's mind, the mind consciousness—the aware mind—coordinates with it to manifest the realms of the six sense objects and to discern the six sense objects; thus there exist the six consciousnesses capable of seeing the realms of the six sense objects. The six sense objects that are seen are called the marks of the sense-object realm, and thus mind and its objects all appear in full.