Mahathera Ledi Sayadaw gives me a new way to look at the group karmic effect notion:
Again, the result of kamma is taken to be twofold: as drifting, affecting the individual, and as overflowing, affecting others. Of these the former implies prosperity, or adversity experienced by a man in this or that existence as an individual being, in consequence of his meritorious or demeritorious deeds. Under this aspect the result of kamma affects the doer of the deed only. But in his existence as an individual being, owing to the heat and power of his kamma promoting his happiness, or causing him misery, there arise conditions of prosperity, or adversely, with respect to persons other than himself. This is called the overflow of the result of kamma. Under this aspect the result of his kamma is shared by others.
The drifting course of the result of kamma may be illustrated by the prosperity of King Mahasudassana's life in the Mahasudassana-sutta.
Moreover, owing to the power of the meritorious deeds of the king, various conditions of prosperity in the lives of other persons arose, some together with his own condition, some coming from this or that source. This may be taken as an illustration of the overflowing course of the result of kamma. It may even promote the happiness of the inhabitants of other continents.
As regards evil deeds, the story in which the whole kingdom was ruined in consequence of the overflowing course of King Nalikera's act, persecuting five hundred sages, and such other stories may be related.
Again, it is written: 'A person, Bhikkhus, may be so born as to promote the well-being of many men, the happiness of many men, the interests of many men, the well-being and happiness of many gods and men. A person, Bhikkhus, may be so born as to increase the ill of many men, the misery of many men, the ruin of many men, the ill and misery of many gods and men.'
It not only affects beings, animals as well as men, but it also permeates the realm of space, and the whole organic world. Thus we read in our texts:
'It is,the rule, Bhikkhus, that when the Bodhisatta, having
fallen from the Tusita-heaven, enters his mother's womb, then
there appears throughout this world including the celestial
worlds, an infinitely splendid radiance surpassing in splendour
the divine radiance of gods, and then the ten thousand
world-systems tremble, shake and quake. Such is the
overflowing result of a Bodhisatta's acts of fulfilling many
When men become exceedingly sinful in thought and deed, all the overflowing course of their kamma rushes from this extensive earth up to the orbits of moon, sun and stars, agonising even the whole realm of space, and the whole organic world of trees, etc., undermining by degrees the cause of prosperity and strengthening that of adversity.
What do you think of this "overflow" idea of vipaka, resulting from the "power or heat" of actions?