Greek ἰσονομία (isonomia)
The principle of equal distribution, reported by the Epicurean spokesman Velleius in Cicero's On the Nature of the Gods: in an infinite universe, things of every kind are balanced by their counterparts, so that, for example, the mortal is balanced by the immortal.
1. Key Texts
These discoveries of Epicurus are so acute in themselves and so subtly expressed that not everyone would be capable of appreciating them. Epicurus teaches that the substance and nature of the gods is such that, in the first place, it is perceived not by the senses but by the mind, but by our perceiving images owing to their similarity and succession, because an endless train of precisely similar images arises from the innumerable atoms and streams towards the gods, our mind with the keenest feelings of pleasure fixes its gaze on these images, and so attains an understanding of the nature of a being both blessed and eternal. Moreover there is the supremely potent principle of infinity, which claims the closest and most careful study; we must understand that it has the following property, that in the sum of things everything has its exact match and counterpart. This property is termed by Epicurus isonomia, or the principle of uniform distribution. From this principle it follows that if the whole number of mortals be so many, there must exist no less a number of immortals. (Yonge)