How Do the Internal and External Dust of Food and Drink Arise, Cease, and Transform?

The act of eating is not necessarily an attachment arising from the mental faculty. When the Buddha manifested in the human realm, He engaged in eating activities, and the great Bodhisattvas also eat. None of them harbor greed or attachment towards food. For some sentient beings, eating stems from the mental faculty's attachment, accompanied by craving for form, sound, smell, taste, touch, and dharmas. Some sentient beings neither cling nor crave, just as the Buddha and Bodhisattvas do not. For what purpose do they eat? It is to nourish the physical body, enabling it to maintain normal activities of the five aggregates in order to liberate sentient beings. Ordinary people eat partly to sustain their physical bodies, but on the other hand, they exhibit greed, hatred, and delusion, revealing their attachments. During the process of eating, Buddhas and Bodhisattvas are free from the afflictions of greed, hatred, and delusion; this is the distinction between Buddhas and ordinary sentient beings.

Food and drink are composed of the four fundamental elements (earth, water, fire, wind). Even without chewing, they undergo momentary arising and ceasing, changing in every instant. The seeds of the four elements arise and then instantly cease back into the Tathagatagarbha; they arise and return, constantly undergoing this process of birth and cessation. Even when food is chewed into small pieces, it remains composed of the four fundamental elements. The chewed food becomes fine particles, eventually turning into the minutest particles, yet it is forever a combination of the four fundamental elements, perpetually arising and ceasing in every instant.

The food and drink that contact the sentient being's tongue, oral cavity, and teeth are external dust (objective matter). The food perceived by the tongue consciousness and body consciousness is internal dust (subjective perception). When the teeth crush the external dust, the internal dust contacted by the body consciousness also becomes fragmented. Ultimately, the external dust turns into fine particles entering the stomach and intestines, and the internal dust contacted by the body consciousness and mental consciousness also enters the stomach and intestines. Finally, when the food in the stomach and intestines is metabolized and ceases to exist, even excreted from the body, the internal dust contacted by the body consciousness and mental consciousness vanishes. Similarly, the internal flavor-dust discerned by the tongue consciousness and mental consciousness, once it moves from the oral cavity into the esophagus, can no longer be tasted. However, within the stomach and intestines, there still exist altered external flavor-dust and internal flavor-dust; it is just that the tongue consciousness cannot taste them. After metabolism and excretion from the body, both the external and internal flavor-dust completely disappear. How are these external and internal dust related? How do they transform?