It is interesting to note that these twelve links in the chain extending in three sections over three lives are all but the manifestations of sorrow to the bringing in of which they naturally determine one another. Thus _Abhidhammatthasa@ngaha_ says "each of these twelve terms is a factor. For the composite term 'sorrow,' etc. is only meant to show incidental consequences of birth. Again when 'ignorance' and 'the actions of the mind' have been taken into account, craving (_t@r@s@nâ_), grasping (_upâdâna_) and (_karma_) becoming (_bhava_) are implicitly accounted for also. In the same manner when craving, grasping and (_karma_) becoming have been taken into account, ignorance and the actions of the mind are (implicitly) accounted for, also; and when birth, decay, and death are taken into account, even the fivefold fruit, to wit (rebirth), consciousness, and the rest are accounted for. And thus:
Five causes in the Past and Now a fivefold 'fruit.'
Five causes Now and yet to come a fivefold 'fruit' make up the Twenty Modes, the Three Connections (1. sa@nkhâra and viññâna, 2. vedanâ and tanhâ, 3. bhava and jâti) and the four groups (one causal group in the Past, one resultant group in the Present, one causal group in the Present and one resultant group in the Future, each group consisting of five modes) [Footnote ref 2]."
These twelve interdependent links (_dvâdas'â@nga_) represent the pa@ticcasamuppâda (_pratâtyasamutpâda_) doctrines (dependent origination) [Footnote ref 3] which are themselves but sorrow and lead to cycles of sorrow. The term pa@ticcasamuppâda or pratîtyasamutpâda has been differently interpreted in later Buddhist literature [Footnote ref 4].
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[Footnote 1: This explanation probably cannot be found in the early Pâli texts; but Buddhagho@sa mentions it in _Suma@ngalavilâsinî_ on _Mahânidâna suttanta_. We find it also in _Abhidhammatthasa@ngaha_, VIII. 3. Ignorance and the actions of the mind belong to the past; "birth," "decay and death" to the future; the intermediate eight to the present. It is styled as tri@kâ@n@daka (having three branches) in _Abhidkarmakos'a_, III. 20-24. Two in the past branch, two in the future and eight in the middle "_sa pratîtyasamutpâdo dvâdas'â@ngastrikâ@n@daka@h pûrvâparântayordve dve madhye@s@tau_."]