Categories of Form, Sound, Smell, Taste, and Touch

Form, sound, smell, taste, and touch are divided into many kinds. The Yogācārabhūmi-śāstra, in its first volume, discusses the kinds of sounds, dividing them into several types. The sense-object of taste is also divided into several kinds—some are produced by the tathāgatagarbha within sentient beings' own bodies. The same is true for the sense-object of touch, and likewise for the sense-object of smell. The sense-object of dharmas, in combination with the five sense-objects, is also simultaneously divided into several kinds.

Among sounds, some are produced by the combination of the physical body and the external world, some are purely external sounds, and some arise from the interactions among sentient beings. The sounds of sentient beings themselves are produced solely by their own tathāgatagarbha. Sounds arising from within the body are also divided into several kinds: those produced by the control of consciousnesses and the initial application and sustained examination (vitarka-vicāra) and deliberation of the mind consciousness; those produced in the process of food absorption and digestion; those produced by pathological changes in the internal organs; those produced by the manas regulating eating, chewing, and swallowing; those produced by the peristalsis of the stomach and intestines; those produced by autonomous breathing; and those produced by the operation of the internal organs, such as the sound of the heartbeat.