Among the five aggregate factors of experience (phung-po lnga, Skt. pancaskandha), the aggregate of forms of physical phenomena (gzugs-kyi phung-po) includes the particles of the four elements (earth, water, fire and wind) and the objects made of these elements. These objects include
- Sensory objects (’dod-yon, desirable sensory objects)
- Physical cognitive sensors (dbang-po, Skt. indriya, sense powers).
The Vaibhashika, Chittamatra and Madhyamaka tenet systems, but not the Sautrantika, also include as objects made of the four elements:
- Forms of physical phenomena included (only) among the cognitive stimulators that are (all) phenomena (chos-kyi skye-mched-pa’i gzugs).
Sensory Objects
Sensory objects are knowable by both sensory and mental cognition. They include:
- Sights (gzugs)
- Sounds (sgra)
- Smells (dri)
- Tastes (ro)
- Tactile and other physical sensations (reg-bya).
Sights include those perceivable to ordinary human eyes and those that are not, such as the bodies of ghosts, gods, anti-gods, and hell-creatures on the plane of sensory objects of desire (the Desire Realm), the bodies of the gods on the plane of ethereal forms (the Form Realm) and bardo-beings. In Western terms, they would thus include parts of the light spectrum invisible to human eyes, such as infrared and ultraviolet.
Sights also include the revealing forms (rig-byed-kyi gzugs) of the body. They reveal the valence of the karmic impulse (constructive, destructive or, only on the plane of ethereal forms, unspecified ) that causes them to arise. The Vaibhashika school explains them as the shape of the body (as a substantial entity separate from color) while implementing preparatory, actual and follow-up methods for committing the actions, such as stalking a deer, shooting the shot that kills it and then skinning it, cooking it and eating the meat. The Sautrantika school asserts that the revealing forms as asserted by Vaibhashika are only hypothetical and cannot perform any functions. The Chittamatra and Madhyamaka schools explain these revealing forms of the body as the shape of the visible motion or movement of the body during these three phases – with “shape” meaning the shape of an assemblage of colored particles. Vaibhashika, Sautrantika-Svatantrika and Prasangika assert revealing forms as a type of karmic impulse, whereas Sautrantika, Chittamatra and Yogachara-Svatantrika do not assert them as being karmic.
In more detail, sights include colors and shapes. The primary colors are blue, yellow, red and white. The branch colors are the colors of clouds, smoke, dust, mist, shadow, sunshine, the sparkle of gems and darkness. Shapes include long, short, flat, curved, high, low, level and not level.
Sounds likewise include those perceivable to ordinary human ears and those that are not, such as high frequency sounds audible to dogs. They include both sounds that communicate information, like speech, and noncommunicating ones, such as the sound of the wind. They also include the revealing forms of constructive and destructive actions of speech, explained by the various tenet systems in similar ways as they explain them in relation to actions of the body. Tactile and other physical sensations include four causal ones: solid, liquid, heat and wind (motion); and seven resultant ones: soft, hard, heavy, light, cold, hunger and thirst.
Although the texts are not clear on this point, Sambhogakayas (longs-sku, Corpuses of Full Use) of a Buddha and illusory bodies (sgyu-lus) attained on the complete stage (rdzogs-rim) of anuttarayoga tantra would most likely need to be included as sights. This is because they are visible to the eye consciousness of arya bodhisattvas.
Void-forms (stong-gzugs) attained on the first two stages of the Kalachakra complete stage would also be sights since they are visible to the advanced awareness (mngon-shes, heightened awareness, extrasensory perception) of eye consciousness. This classification is problematic, however. Vasubandhu in A Treasure House of Special Topics of Knowledge (Chos mngon-pa’i mdzod, Skt. Abhidharmakośa) explains that advanced awareness may be with sensory consciousness. Asanga in An Anthology of Special Topics of Knowledge (Chos mngon-pa kun-las btus-pa, Skt. Abhidharmasamuccaya), however, explains that advanced awareness occurs with a mental consciousness that relies on special powers of the eye-sensors (the photosensitive cells of the eyes).
Physical Cognitive Sensors
The physical cognitive sensors are the dominating conditions (bdag-rkyen) for their own specific types of sensory consciousness. They include:
- The photosensitive cells of the eyes (mig-gi dbang-po)
- The sound-sensitive cells of the ears (rna’i dbang-po)
- The smell-sensitive cells of the nose (sna’i dbang-po)
- The taste-sensitive cells of the tongue (lce’i dbang-po)
- The cells of the body that are sensitive to physical sensations (lus-kyi dbang-po).
Forms of Physical Phenomena Included Only among Cognitive Stimulators That Are All Phenomena
Forms of physical phenomena included only among cognitive stimulators that are all phenomena are not knowable by sensory cognition, but are only knowable by non-conceptual or conceptual mental cognition. Technically, they cannot be included among the five external cognitive stimulators, which refer to the five types of sensory objects, since such forms of physical phenomena can be objects of both sensory and mental consciousness.
According to Chittamatra and Madhyamaka, these special forms of physical phenomena include:
- Forms of physical phenomena derived from what have been amassed together (bsdus-pa-las gyur-pa’i gzugs), such as atoms and subatomic particles derived from mentally deconstructing coarse material objects
- Forms of physical phenomena that are open spaces (mngon-par skabs yod-pa’i gzugs), such as the open space to a distant mountain, astronomical distances between stars and microscopic distances between atoms
- Forms of physical phenomena arising from having properly received them (yang-dag-par blangs-pa-las byung-ba’i gzugs), such as the nonrevealing forms (rnam-par rig-byed ma-yin-pa’i gzugs) of vows
- Forms of physical phenomena that are totally imaginary (kun-brtags-pa’i gzugs), such as sensory objects in dreams and the conceptually implied objects (zhen-yul) of certain conceptual cognitions, such as the bones conceptually implied when imagining the ground filled with bones, but not actually emanating them, or the Avalokiteshvara implied when conceptually visualizing Avalokiteshvara
- Forms of physical phenomena arising from meditative power (dbang-’byor-pa’i gzugs), such as the fire or skeletons emanated and cognized by the power of absorbed concentration (ting-nge-’dzin, Skt. samādhi).
Sautrantika-Svatantrika and Prasangika assert non-revealing forms of vows as being karmic impulses, whereas Chittamatra and Yogachara-Svatantrika do not assert them to be karmic. Vaibhashika asserts forms of physical phenomena included only among the cognitive stimulators that are all phenomena to include only forms of physical phenomena arising from having properly received them – namely, vows – and asserts them as being karmic impulses. Sautrantika does not accept the existence of forms of physical phenomena included only among the cognitive stimulators that are all phenomena. Thus, Sautrantika refutes that vows are nonrevealing forms.