Types 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, discussed 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 sense-object of touch is like this as well, and so is the sense-object of smell. The mental sense-object, combined with the five sense-objects, is likewise simultaneously divided into several kinds.

Sounds include those born from the combination of the physical body and the external environment, sounds that come purely from the external environment, and sounds produced when sentient beings interact with one another. 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 through control by the conscious mind, arising from the mind consciousness's initial application and sustained examination (vitarka-vicāra) and deliberation; those produced during the process of digestion and absorption of food; 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 functioning of the internal organs, such as the sound of the heartbeat.