The Manas is the Driving Force for the Arising of All Dharmas in the Three Realms.

The manas prompts the tathāgatagarbha to produce the material universe (the inanimate vessel-world); likewise, it is the karmic seeds that prompt the tathāgatagarbha to bring forth the material universe. The manas corresponds with the karmic seeds, and the manas thus represents karma—whether wholesome karma, unwholesome karma, or karma that is neither wholesome nor unwholesome.

The birth of the material universe is preparation for the birth and survival of the five aggregates (pañca-skandha), and it is also a dharma existing within the three realms. Because of the karmic seeds, when the karmic conditions ripen, they prompt the tathāgatagarbha to output the seeds of the four great elements, forming the four great elements. The tathāgatagarbhas of all sentient beings jointly transform and construct the material universe; only after it is constructed can sentient beings be born. The purposiveness lies with the manas. If the manas has no purpose, the karma of the three-realm world ceases, and—like an arhat—one enters nirvāṇa without remainder (Anupadhiśeṣa-nirvāṇa); in this way, the three realms also disappear. 

The teaching of the twelve links of dependent origination explains precisely this principle: when karmic causes and conditions ripen, sentient beings are born; without the material universe, there is no environment for survival, and the causes and conditions for sentient beings' birth would not ripen. This condition is also brought about by the manas—the manas is the motive force behind the arising of all dharmas in the three-realm world.