The Profound Yogācāra Meaning of the Diamond Sutra (25)

Next, let us look at the eighteen dhātus, which include the six faculties, six sense objects, and six consciousnesses. The six faculties are the eye, ear, nose, tongue, body, and mental faculties (manas). The eye faculty is divided into the gross physical sense organ and the supreme faculty (rūpa-prasāda). It is composed of the four great elements of earth, water, fire, and wind. The grape-cluster-like structure on the outside of the body is called the gross physical sense organ, also known as the external eye faculty. Connected via the optic nerves to the occipital cortex at the back of the brain, which governs vision, is the supreme faculty, upon which eye consciousness depends; it is there that eye consciousness arises. If the supreme faculty is damaged, even if the eye faculty is intact, one cannot see forms—this is called being blind with open eyes. The eye faculty is formed at the fertilized-egg stage when the tathāgatagarbha absorbs the four great elements of earth, water, fire, and wind (nutrients) from the mother's body. It is a dharma of arising and ceasing, an impermanent dharma, a false and illusory dharma; it is suffering, and thus it is not-self.

The ear faculty is divided into the gross physical sense organ and the supreme faculty. The one on the outside of the body that everyone can see, shaped like a newly curled leaf, is called the gross physical sense organ; connected via the auditory nerves to the auditory cortex at the back of the brain is the supreme faculty, upon which ear consciousness depends; it is there that ear consciousness arises. The ear faculty is formed in the embryo by the tathāgatagarbha absorbing nutrients from the mother's body. It is a dharma subject to arising and ceasing, an impermanent and false dharma, suffering and not-self in nature.

The nose faculty is divided into the gross physical sense organ and the supreme faculty. The gross physical sense organ is on the surface of the body, resembling a pair of olfactory bulbs or a hanging gallbladder; it is the receptor for odors. After receiving odors, they are transmitted via the olfactory nerves to the cerebral cortex, where nose consciousness arises, and only then can one distinguish fragrant from foul. The cerebral cortex at the back of the brain is the supreme faculty, governing the sense of smell, upon which nose consciousness depends. The nose faculty is also formed at the fertilized-egg stage by the tathāgatagarbha; it is subject to arising and ceasing, impermanent, false and illusory, suffering, and not-self.

The tongue faculty is composed of the four great elements of earth, water, fire, and wind, and is transformed and generated by the tathāgatagarbha at the fertilized-egg stage. It is divided into the gross physical sense organ and the supreme faculty. The one outside the body, visible upon opening the mouth, shaped like a half-moon, is the gross physical sense organ; it is the receptor for taste. Taste sensations are transmitted via the gustatory nerves to the cerebral cortex, where the tathāgatagarbha gives rise to tongue consciousness, which discriminates the various taste objects. The cerebral cortex at the back of the brain is the supreme faculty. The tongue faculty is subject to arising and ceasing, false and illusory, impermanent, suffering, and thus not-self.

The body faculty is created by the four great elements of earth, water, fire, and wind, aggregated from thirty-six constituents. The external appearance comprises twelve: hair, body hair, nails, teeth, eye discharge, tears, saliva, snot, feces, urine, grime, and sweat. The bodily vessels comprise twelve: skin, flesh, blood, muscle, sinews, vessels, bones, marrow, fat, grease, brain, and membranes. The internal category comprises twelve: liver, gallbladder, intestines, stomach, spleen, kidneys, heart, lungs, raw viscera, cooked viscera, red phlegm, and white phlegm. The skin and muscles of every part, down to the internal organs, all have sensation, transmitted via the nerves to the spinal cord and then to the cerebral cortex, where body consciousness is produced and only then can tangibles be felt. The cerebral cortex is the supreme faculty, located at the back of the brain; if this part is damaged, the entire body becomes paralyzed and the person becomes a vegetable. The gross physical sense organ is like a barrel of flesh, visible to the human eye, and is thus called the gross physical sense organ. The body faculty is subject to arising and ceasing, impermanent, false and illusory, suffering, and thus not-self.