Lecture Notes on the Sūtra of the Collection of the Father and Son (Pitāputrasamāgamanasūtra) (210)

Those who have not realized the first bhūmi are called ordinary beings/worldlings (pṛthagjana); those who have attained the first bhūmi are noble ones, who have eliminated the ordinary being's nature and no longer create evil karmic deeds of birth and death. All sentient beings who have not severed the karmic seeds of defilement pertaining to birth and death belong to the category of ordinary beings. When this lifespan ends, there will be another life, only born at another time and in another place—whether in the heavens, the human realm, hell, or among hungry ghosts—this is called being born at a different time and in a different place. Both first-bhūmi bodhisattvas and ordinary beings have segmented birth-and-death. For example, a human lives one life of a hundred and eighty years, or a thousand eight hundred years; when the lifespan ends, there is the next life—birth and death occur in segments, hence it is called segmented birth-and-death. If a first-bhūmi bodhisattva is reborn in the heavenly realms, the lifespan is extremely long; if reborn in the human world, the lifespan is the same as that of ordinary sentient beings, and there is still segmented birth-and-death; if reborn in the animal realm through the power of vows, the lifespan is as brief as that of animals, and there is also segmented birth-and-death. Besides segmented birth-and-death, there is also transformational birth-and-death/subtle birth-and-death. Transformational birth-and-death means that although the lifespan is extremely long, the tathāgatagarbha mind still contains defiled seeds of birth and death that have not all been eliminated, and can still give rise to the karma of birth and death, so the false appearance of birth and death cannot be permanently extinguished. Before the stage of buddhahood, the seeds of arising and ceasing in the mind cannot be eradicated; therefore there is transformational birth-and-death.