The twelve links of dependent origination are part of the central teachings of Buddha which analyse the causes and conditions leading to samsaric life.
Lord Buddha mentioned “If he who sees the dependent origination, he sees the dhamma”. In this world there is a cause for everything that happens. When the cause is removed the effect ceases. Just like how a seed gives rise to a plant. In this manner we can explain the birth and death of beings based on dependent origination. The cause of suffering in samsara and the eradication of such suffering are explained in accordance with dependent origination.
“Whenever this is present, this is also present. Whenever this is absent, this is also absent.” (Udana)
“From the arising of this, this arises. From the cessation of this, this ceases to be.” (Udana)
This cause and effect theory can also be seen in major central teachings of Buddha as in 4 noble truths (there is a cause and end of suffering), eightfold path (how the 8 factors are inter-related), Kamma (law of cause and effect) and dependent origination as below.
12 links of dependent origination are:
Volitional formations (Sankhara)
Mind & Body (Nama-Rupa)
Six Sense spheres (Salayatana)
Ageing and death (Jara-marana)
1st Link: Ignorance (Avijja)
Ignorance is illustrated like a blind person who blunders over obstacles and can’t see where she is going. Ignorance is like blindness, lack of insight into the reality of things namely the reality of the four noble truths. Not seeing there is dukkha (suffering), not destroying the cause of dukkha, letting this craving to impel us to seek more lives & more pleasures and not knowing the path to cease dukkha, getting out of samsara.
Due to the ignorance of four noble truths, we have set in motion this wheel bringing about old age and death and all other sorts of other sufferings (dukkha). Because of previous existences, there was volitional action and kamma made in those past lives setting up the 2nd link.
2nd link: Volitional formations (Sankhara)
Sankhara is illustrated like a potter forms clay into something new, an action spins off a sequence that leads to new sequences. Likewise, an action creates a predisposition in mind. Intentional actions have the latent power within them to bear fruit in future (in this life, in next life or in more distant future lives); kamma effects waiting to ripen.
Because of the past kamma wholesome and unwholesome that we have collected in previous lives we have ensured the continued experience in this world.
The existence of these volitions produced preciously result in consciousness called “relinking” which becomes the basis of this present life. (Third link).
3rd link: Consciousness (Vinnana)
The rebirth consciousness or “consciousness” that links on is illustrated like a monkey jumping from tree to tree. The monkey represents the very primitive spark of sense-consciousness which is the first moment in the mental life of the new being. Relinking consciousness is not something that can be controlled by will.
This relinking consciousness is the third constituent necessary for conception for even though mother’s period and sperm is deposited in womb, if there is “no being” desiring to take rebirth at that place and time there will be no fertilisation of the ovum, there will not be rebirth.
From relinking-consciousness there is the arising of mind-body (4th link).
4th Link: Mind-body (Nama-Rupa)
Mind-body is illustrated by people sitting in a boat with one of them steering it. The boat symbolises form, and its occupants, the mental aggregates. Rupa is usually thought of as body, while mind is a compound of feeling, perception, volition and consciousness.
But it is in the mind that a change can be wrought instead of drifting through life at the mercy of the inherent instability of mind and body. So as per the illustrtion it is the mind that is doing the work of punting the boat of psycho-physical states on the river of cravings, while body is just the passive passenger.
With the coming into existence of mind-body, there is the arising of the Six Sense-spheres (5th link).
5th Link: Six Sense - Sphere (salayatana) The six sense spheres are the 'portals' whereby we gain our impression of the world. Each of the senses is the manifestation of our desire to experience things in a particular way.
These corresponding six senses are eye, ear, nose, tongue, touch and mind, and these are the bases for the reception of the various sorts of information. This information falls under six headings corresponding to the six spheres: sights, sounds, smells, tastes, tangibles and thoughts.
Because of existence of six sense spheres, there comes the 6th link which is “Contact”.
6th Link: Contact (phassa)
Contact is referring to the contact of the sense organs with the respective objects. With this link, the psychophysical organism begins to interact with the world.
For instance, when the necessary conditions are all fulfilled, the eye sees a sight object, the person became aware and turned toward the object, there comes eye-contact, the striking of the object upon the sensitive eye-base (activating the eye consciousness). Likewise the other sense spheres.
Because of the contact with sense objects, arises feelings (7th link) for it.
7th Link: Feeling (vedana)
When there have been various sorts of contact through the six senses, feelings arise which are the emotional response to those contacts. Feelings are of three sorts: pleasant, painful and neither pleasant nor painful.
But all feelings are unstable and liable to change (impermanence/ anicca), for no mental state can continue in equilibrium.
When feelings arise, Cravings (8th link) are (usually) produced.
8th Link: Craving (tanha)
Craving is illustrated by a person addicted to drinking beer. Even though it harms you, no matter how much you drink, you just keep on drinking. Also known as attachment, it is a mental factor that increases desire without any satisfaction.
Up to this point, the succession of events has been determined by past kamma. Craving, however, leads to the making of new kamma in the present and it is possible now, and only now, to practice Dhamma and breakthrough from the cyclic life.
When one does have mindfulness one may and can understand feelings: "this is pleasant feeling," "this is unpleasant feeling," "this is neither pleasant nor unpleasant feeling" and such contemplation of feelings leads one to understand and beware of the 3 evil roots (greed, hatred and delusion), which are respectively associated with the three feelings.
With this knowledge and understanding then one can break out of the Wheel of Birth and Death. But without this Dhamma-practice it is certain that feelings will lead on to more cravings and whirl one around this wheel full of dukkha again and again.
There are three kinds of cravings: craving for sensual pleasure, craving for existence and craving for non-existence.Craving is the cause of suffering as per second noble truth.
Where the kamma of further craving is produced there arises Grasping (9th link).
9th link: Grasping (upadana)
Grasping is also known as clinging, it means mentally grabbing at an object one desires and not letting go.
Grasping is fourfold: 1. Attachment to sensual pleasures 2. Attachment to wrong and evil views 3. Attachment to mere external observances, rites and rituals 4. Attachment to self, an erroneous lasting soul entity. (opposite of non-self Anatta)
Because of this clinging which is described as craving in a higher degree, man becomes a slave to passion.
Where this grasping is found, becoming (10th link) arises.
10th Link: Becoming (bhava)
Becoming is illustrated by a woman in late pregnancy. Just as she is about to give birth a fully developed child, the karma that will produce the next lifetime is fully potentialized though not yet manifest until birth.
The Buddhist way of doing things is to let go the fires of "wanting" by stopping the process of craving and grasping and thus cutting off ignorance (first link) at its root. If we want to stay in samsara we must be diligent and see that our 'becoming', which is happening all the time shaped by our kamma, is 'becoming' in the right direction.
In the presence of Becoming there is arising in a new birth (11th link)
11th Link: Birth (jati)
Birth is illustrated by a woman giving birth to a newborn child. Birth means the appearance of the five aggregates (material form, feeling, perception, formation and consciousness) in the new being.
If we are not able to bring the wheel to a stop in this life, certainly that future will arise conditioned by the kamma made in this life. When birth’s no longer brought about, all the links will be stopped."
Naturally where there is Birth, is also Old-age and Death (12th link).
12th link: Ageing and Death (jara-marana)
The final link is illustrated by a person growing old and finally passed away. Ageing is both progressive, occurring every moment of our lifetime, and degenerative which leads to death.
The noble eightfold path leads directly to Deathlessness, the going beyond birth and death, beyond all dukkha.
The two primary roots are ignorance and craving. Ignorance is not knowing the 4 noble truths, ignorant of the past, future and both past and future or not knowing things as they truly are. Craving just like ignorance drives man’s desires and more samsaric becomings.
The three connections are: 1. Between ignorance and volitional formations. 2. Feelings and cravings. 3. Becoming and Birth. Buddha said that when any of the links of this chain is broken, the wheel of becoming comes to an end, resulting in the cessation of suffering. This is called the law of dependent origination in reverse order which clarifies the 3rd noble truth (there is cessation of suffering) and the 4th noble truth (there is a path that leads to the cessation of suffering).