This part of The Heart Sutra refers to the formula of the Twelve Links in the Chain of Causation: These are in the sphere of the five skandhas. As we have seen, the five skandhas were found to be empty; consequently, the twelve links are also void. The pratyekabuddha, or saint, of the Middle Vehicle, who practices the Dharma of the Twelve Links and who has attained Enlightenment by that means, is liberated from his or her allotment of birth and death, but has not reached the realm of Buddhahood. However, the Buddha taught the Prajna Paramita Sutra to bring people closer to the attainment of Buddhahood by means of a deep understanding of all dharmas as manifesting Reality and Emptiness. Hence, someone endowed with superior wisdom and the highest potential who understands that all dharmas are void can attain Buddhahood immediately.

The attainment of the pratyekabuddha is the outcome of his or her practice based on the Dharma of the Twelve Links in the Chain of Causation, or causes and conditions. Causes and conditions act as the support for the twelve links, a concept which confuses people even further. Ignorance conditions karmic action; karmic action conditions consciousness; consciousness conditions name and form; name and form condition the six sense-doors (sense-organs); the six sense-organs condition contact; contact conditions sensation; sensation conditions craving; craving conditions grasping; grasping conditions becoming; becoming conditions birth; birth conditions old age and death, sorrow, pain, grief, lamentation, despair and anguish. The Twelve Links in the Chain of Causation, in combination with causes and conditions, illustrate how confusion contributes to human suffering.

Let me explain further. Ignorance in the context of the Buddha's teaching means either not knowing or knowing incorrectly; the term is interchangeable with confusion. Assumptions based on ignorance support or condition unskillful actions. Action rooted in confusion reinforces the bias generated by ignorance.

Consciousness is the prime agent in the selection of conditions for rebirth: If there is confusion present during the intermediate existence between death and rebirth, proper conditions for the next existence will not be recognized. In this respect it is the consciousness that conditions name and form.

Name and form at the beginning of a new existence are simply the sperm of the father combined with the ovum and blood of the mother; the form already exists, but the name part has yet to develop. The eighteen realms that eventually come into existence will be conditioned from the very beginning by name and form.

The six organs develop on the basis of corporeality and of the seeing, hearing, smelling, tasting, touching and knowing natures, with a discriminatory bias already built in. The six senses develop on the basis of the six organs: The six organs, being the sense-doors, condition contact.

Contact takes place when a sense-organ produces sense data in response to stimulation. In the case of a newborn, the earliest experience is tactile: There is an abrupt change of environment in terms of temperature and texture, causing intense discomfort in the newborn baby, making it cry. The contact conditions sensation.

As the range of stimuli widens, diversity of contact increases; the material sense-organs develop accordingly, each becoming progressively specialized and its own realm more and more specific. Eye, ear, nose, tongue, body and mind develop preferences and aversions, giving rise to greed and anger. Therefore, it is said that sensation conditions craving.

Craving is sometimes interpreted as thirst. Initially, it is the thirst for the continuation of one's existence, construed as independent. That notion is the anchor for the impulse to grasp. Grasping leads inevitably to clinging, which brings new becoming in its wake.

Becoming may be described as setting the stage for new birth. It is the unavoidable outcome of grasping.

Birth is conditioned by becoming. It introduces a new round in the cyclic pattern of existence; because there is birth, old age and death automatically follow.

Old age and death require care and produce pain, grief and anguish. Most human beings, when approaching death, are ravaged by grief and anxiety. They hold on to their thirst for existence, which is entrenched through lifelong habits; their suffering and their fear are similar to what a tortoise experiences when its shell is removed. Death and dying are frequently accompanied by manifestations of grief.

Birth, death, and all the suffering in between arise because of ignorance and supportive conditions, and ordinary people have no choice but to continue the cycle of continual rebirth in the Six Realms. The pratyekabuddha, understanding the source of defilement and of birth and death and on hearing the Dharma of the Twelve Links in the Chain of Causation, will generate the mind of Tao and practice to end his or her own suffering. He or she will attain the path and fruit of the Middle Vehicle, thereby ending the allotment of birth and death.

To free oneself from confusion or ignorance is requisite for right, or correct, practice. When ignorance is eliminated, all delusory activity ceases. There is no more fuel to feed delusion, and, thus, consciousness is extinguished, which means that there is no more birth, no more death. With the six sense-organs extinguished, there is no more contact. In the absence of contact and sensation, there is no longer any greed or hatred, no craving and, therefore, no grasping (no karmic activity); without grasping there can be no becoming, which means that all future rebirths are extinguished. Without birth, there is no aging and death, and that is the end of pain, grief, lamentation and anguish.

The Buddha taught the Prajna Paramita Dharma to awaken practitioners to the teaching of the Void and to make them receptive to it. The Chinese term Wu (none, nothing) implies putting an end to grasping; to understand the essential Void of all existence is to understand the True Mind. To see one's Self Nature enables the swift attainment of Buddhahood, because, when ignorance is recognized as void, there is nothing left to break off. Therefore the Sutra says, "Also, no ending of ignorance." Since, originally, there is no such thing as old age and death (the products of conceptual mind), the Sutra says, "Until we come to no old age and death and to no ending of old age and death."