The 28 kinds of matter (rūpa)

What is matter? — that which is “afflicted”

In the Khajjanīya Sutta the Buddha says it is called rūpa because it is “afflicted”: it is changed by cold, heat, hunger, thirst and contact with flies, mosquitoes, wind, sun and creeping things.

Matter differs from consciousness and mental factors in that it knows nothing at all. Our body does not “feel” heat; the consciousness that depends on the body knows the heat. The body is like a tool used by the mind. External matter, such as trees, stones and air, is matter too, just without a mind depending on it.

The four great elements — not the earth, water, fire and air of nature

In the Abhidhamma an element is not a substance but a “characteristic” present in all matter. Even a lump of iron has the water element, and water has the earth element. The Visuddhimagga describes the characteristic and function of each:

• Earth (paṭhavī) — characteristic: hardness or softness; function: serving as a foundation for other matter. The softness of a pillow is the earth element in its soft mode.
• Water (āpo) — characteristic: flowing or cohesion; function: holding other matter together, as water binds flour into dough.
• Fire (tejo) — characteristic: heat or cold; function: ripening, warming, ageing. The cold of ice is the fire element at a low level.
• Air (vāyo) — characteristic: distension or support; function: causing motion, such as the tightness of the belly on a deep in-breath.
• Worth knowing: water is the only element that cannot be known through the body. When we touch water, the body knows coolness (fire), softness (earth) and pressure (air); cohesion is known only by the mind. So the Abhidhamma counts the tangible object (phoṭṭhabba) as three elements: earth, fire and air.

Taking the body apart into elements

In the Mahāhatthipadopama Sutta, Venerable Sāriputta analyses the body by its predominant elements — the sutta method — and points out that the elements inside the body are the same as those outside, so one should not regard them as “mine” or “myself”.

• Earth predominant — head hair, body hair, nails, teeth, skin, flesh, sinews, bones, marrow and internal organs.
• Water predominant — bile, phlegm, pus, blood, sweat, fat, tears, grease, saliva, mucus, joint fluid, urine.
• Fire predominant — the fire that warms the body, that ages it, that burns in fever and that digests food.
• Air predominant — up-going and down-going winds, winds in the belly and intestines, winds coursing through the limbs, and the breath.
• The Mahāsatipaṭṭhāna Sutta gives the simile of a butcher who cuts up a cow and sits at a crossroads: the idea “this is a cow” disappears, leaving only “meat”. In the same way, for one who contemplates the body as elements, the sense of “me” fades.

A map of the 28 kinds of matter

The 18 concretely produced kinds have their own characteristics, arise directly from conditions and can serve as objects of insight. The 10 non-concrete kinds are just modes or qualities of the concrete kinds, such as the space between material groups or the lightness of matter.

The doors of experience: five sensitivities and their objects

Sensitive matter (pasāda-rūpa) is the “clear” part of each sense organ that can receive an object, like a mirror receiving an image — not the whole eyeball or ear. Eye-sensitivity is a tiny clear area in the eye that receives colour; ear-sensitivity a clear area in the ear that receives sound, and so on.

Objective matter (gocara-rūpa) is what the sensitivities know: colour (what appears to the eye), sound, smell, taste and the tangible, which is the earth, fire and air elements. These five pairs are the source of all experience through the five doors, studied in the lesson on the cognitive process.

The remaining concrete matter

• Sex matter (bhāva-rūpa), 2 — femininity and masculinity, giving female or male features, manner and disposition.
• Heart-base (hadaya-rūpa), 1 — the base of the mind-door consciousnesses, i.e. all those other than seeing, hearing, smelling, tasting and touching. The commentaries locate it in the heart; the Paṭṭhāna only calls it “the matter on which mind-element and mind-consciousness-element depend”.
• Life faculty (jīvita-rūpa), 1 — sustains kamma-born matter, like water keeping a lotus fresh (the counterpart of the mental life faculty that sustains mental states).
• Nutritive essence (āhāra-rūpa), 1 — ojā, the nourishment in food that makes matter grow.

The 10 non-concrete kinds — modes of matter

• Limiting matter (pariccheda-rūpa, the space element), 1 — the space separating groups of matter, allowing them to be distinguished, such as the ear and nasal cavities.
• Intimating matter (viññatti-rūpa), 2 — bodily and vocal intimation: the mode of matter that conveys the mind's meaning, such as beckoning, nodding and speaking, so others know what we want.
• Mutable matter (vikāra-rūpa), 3 — lightness, malleability and wieldiness of matter, such as a body that feels nimble after a good rest.
• Characteristic matter (lakkhaṇa-rūpa), 4 — production (upacaya), continuity (santati), decay (jaratā) and impermanence (aniccatā): the arising, ageing and ceasing of all matter.

What produces matter? — the four origins

The matter in our bodies does not come from a single cause. The Abhidhamma names four origins of matter, so the body is the combined result of past kamma, the present mind, temperature and food.

Matter always arises in groups — kalāpas

Matter never arises one kind at a time but in tiny groups called “kalāpas”. The smallest group has eight kinds that can never be separated (avinibbhoga-rūpa): earth, water, fire, air, colour, smell, taste and nutritive essence.

This is why the Abhidhamma says that even a stone contains the water element and even a flame contains the earth element. The elements differ only in proportion, which is why things appear different.

Common misunderstandings

• “The four elements are an ancient chemistry.” — No. Elements in the Abhidhamma are characteristics known by direct experience, such as hardness and heat, not chemical compounds.
• “Coldness is the water element.” — No. Coldness is the fire element at a low level. The water element is cohesion, and it cannot be known through the body.
• “Matter means what can be seen.” — No. Matter in the Abhidhamma includes sound, smell, taste, hardness, heat and the sense sensitivities. Visible colour is just one of the 28.
• “Body and mind are completely separate.” — No. They condition each other: the mind produces matter, such as a smile, and the mind depends on matter, such as the eye-sensitivity and the heart-base.
• “The body is vile and should be loathed.” — That is not the aim. Contemplating the body as elements is meant to loosen clinging, not to create hatred. The body is still an important tool for doing good and for practice.