Categories of Form, Sound, Scent, Taste, and Tangible Objects

Form, sound, smell, taste, and touch are each divided into several kinds. In the first volume of the Yogācārabhūmi-śāstra, the categories of sound are discussed, which are divided into several types. The dust of taste is also divided into several kinds, some arising from the Tathāgatagarbha within the sentient being's own body; the dust of touch is similarly divided, as is the dust of smell. The dust of dharma, combined with the five other dusts, is also simultaneously divided into several kinds.

Sound can arise from the conjunction of the material body and the external environment; there are purely external sounds, and there are sounds produced through interactions among sentient beings. The sound produced by a sentient being themselves is generated solely by their own Tathāgatagarbha. Sounds emanating from the body are also divided into several kinds. There are those produced by the controlling mind, arising from the perception, observation, and thinking of consciousness; there are those generated during the absorption and digestion of food; there are those caused by internal organ pathologies and other conditions; there are those produced by the regulation of the mind faculty during eating, chewing, and swallowing; there are those generated by gastrointestinal peristalsis; there are those arising from autonomous respiration; and there are those produced by the functioning of internal organs, such as the sound of the heartbeat.