Does Human Nature Inherently Possess the Ten Dharma Realms?

The Tathāgatagarbha encompasses the natures of all Ten Dharma Realms, whereas the manas (mental faculty) cannot possess the natures of all Ten Dharma Realms. If the manas possessed Buddha-nature, then in a single thought-moment one would be a Buddha. If this were so, would it be possible to be a Buddha for half a day or a full day by extending this single thought-moment to ten, a hundred, or a thousand thought-moments? The manas of a Buddha, a Śrāvaka, a Pratyekabuddha, or a Bodhisattva cannot possess the evil natures of beings in the Three Evil Realms, nor can they possess the natures of ordinary beings within the Six Realms.

The intrinsic nature refers to the mental factors (caittas). By observing the mental factors of the manas, one can understand a person's intrinsic nature. By observing the mental factors of the Tathāgatagarbha, one can further discern the future destination of sentient beings—they will certainly attain Buddhahood without doubt.

The manas of ordinary beings differs vastly from that of Śrāvakas, Pratyekabuddhas, Bodhisattvas, and Buddhas. Moreover, the mental factors of the manas and those of the Tathāgatagarbha also exhibit distinct differences. Only the mental factors of a Buddha's manas are identical to those of the Buddha's immaculate consciousness (amalavijñāna). If sentient beings were Buddhas in the true sense, then the mental factors of their manas should be identical to those of the Tathāgatagarbha: free from afflictive mental factors, fully endowed with the five universally functioning mental factors, fully endowed with the five object-determining mental factors, and fully endowed with the eleven wholesome mental factors.