Today I came across the video below by Gregory Sadler, and it occurs to me to make note of it here as potentially being related to Epicurean views of isonomy. This citation is from Balbus presenting what I gather is the Stoic view of a natural progression in forms of life, but Sadler says several times that this was an argument made by several schools. Certainly if Cicero knew of this, then the Epicureans were familiar with the argument as well.
Since we have so little about isonomia other than the short reference by Velleius in book one of the same work, I'm putting this here as food for future research on whether Epicurean isonomy might share *some* parallels with what Balbus is describing. No doubt the Stoics would argue that this natural progression arises from intelligent design by a divine creator.
But I don't think that it's obvious that the Epicureans could not have developed a similar idea of gradation arising purely from the operation of nature WITHOUT a preexisting intent. On that point, even Balbus refers to nature and says "As in vines or cattle we see that, unless obstructed by some force, nature progresses on a certain path of her own to her goal of full development,"
Joshua will recall the statement of DeWitt that even though nature is nonpurposive, it has created a purposive being in humans. Is it likewise at least arguable (and in fact it is probably better to say it is obviously true) that regardless of the fact that nature had no intent to do so, nature has in fact produced gradations in abilities which we can easily recognize?
And it might be interesting to consider how recognition of such gradations might relate to prolepsis / anticipations, given that prolepsis appears to be central to the argument of how divinity is recognized.
Here's the main quote which I gather is from the Loeb edition of Cicero's On The Nature of the Gods. I have not had time to examine the before and after statements to evaluate the context from which this comes.
QuoteBook Two - Balbus - 33 "Again, if we wish to proceed from the first rudimentary orders of being to the last and most perfect, we shall necessarily arrive in the end at deity. We notice the sustaining power of nature first in the members of the vegetable kingdom, towards which her bounty was limited to providing for their preservation by means of the faculties of nurture and growth. 34 Upon the animals she bestowed sensation and motion, and an appetite or impulse to approach things wholesome and retire from things harmful. For man she amplified her gift by the addition of reason, whereby the appetites might be controlled, and alternately indulged and held in check. But the fourth and highest grade is that of beings born by nature good and wise, and endowed from the outset with the innate attributes of right reason and consistency; this must be held to be above the level of man: it is the attribute of god, that is, of the world, which must needs possess that perfect and absolute reason of which I spoke. 35 Again, it is undeniable p157 that every organic whole must have an ultimate ideal of perfection. As in vines or cattle we see that, unless obstructed by some force, nature progresses on a certain path of her own to her goal of full development, and as in painting, architecture and the other arts and crafts there is an ideal of perfect workmanship, even so and far more in the world of nature as a whole there must be a process towards completeness and perfection. The various limited modes of being may encounter many external obstacles to hinder their perfect realization, but there can be nothing that can frustrate nature as a whole, since she embraces and contains within herself all modes of being. Hence it follows that there must exist this fourth and highest grade, unassailable by any external force. 36 Now this is the grade on which universal nature stands; and since she is of such a character as to be superior to all things and incapable of frustration by any, it follows of necessity that the world is an intelligent being, and indeed also a wise being.