Again, resuming [the same subject,] let us discuss in common such things as Parmenides delivers to us concerning the whole order of Gods that are called assimilative rulers and leaders. For it is necessary, as we have before observed, to refer the whole divided theory [respecting the Gods] to the common and one mystic doctrine of Parmenides. For there we shall find the connexion of the divine orders, and their common powers delivered to us by Plato in a continued series. The same and the different, therefore, define for us the peculiarity of the demiurgic order. And according to these, we have unfolded in what has been before said, the paternal and prolific cause of the demiurgus, his unpolluted fountain, and the separative power in him, conformably to which he divides his own kingdom from that of Saturn. Since, however, the whole order of the assimilative Gods, is suspended from the demiurgic monad, subsists about, is converted to, and perfected by it, it is indeed necessary to refer the signs of this order to the demiurgic signs, and to give to the former a well-ordered generation proceeding in measures from the latter. For thus the coherence of the divine genera with each other, will become more apparent, and the evolution into light of secondary from more ancient natures, will through these very things become perfectly known to us.
What, therefore, are the peculiarities of this order, which is celebrated as of a ruling and leading nature by others, but is demonstrated by arguments to be of an assimilative nature? Every thing then which is assimilative, imparts the communication of similitude, and of communion with paradigms to all the beings that are assimilated by it. Together with the similar, however, it produces and commingles the dissimilar; since in the images [of the similar] the genus of similitude is not naturally adapted to be present, separate from its contrary. If, therefore, this order of Gods assimilates sensibles to intellectuals, and produces all things posterior to itself according to an imitation of causes, it is indeed the first-effective cause of similitude to natures posterior to itself. But if it is the cause of this, it is also of the dissimilitude which is co-ordinate with similitude. For it is necessary that all things which participate of the similar, should also participate of the dissimilar. And this order of Gods indeed imparts the similar in a greater degree than the dissimilar to the progeny that are more proximate to their principles; but it constitutes the essence of things that proceed farther from their principles, according to dissimilitude rather than similitude.
For, in short, similitude will have in itself an hypostasis analogous to the paternal causes, and to the causes which convert to principles. But the hypostasis of dissimilitude is analogous to prolific causes, and to those that preside over multitude and division. For similitude indeed proceeds analogous to intelligible bound, but dissimilitude to intelligible infinity. Hence the former is collective, but the latter separative of progressions. Since, however, every divine nature begins its own energy from itself, and though its energy is directed to secondary natures, and it imparts its own peculiarity to things subordinate, yet it establishes and defines itself according to that energy, prior to other things;--this being the case, that which supplies other things with the participation of the similar and the dissimilar, from itself, will entirely possess in itself this similitude and dissimilitude. It is also mingled from both these, though here similitude is emitted in a greater degree, and there dissimilitude. For generative are united to paternal causes, and unpolluted causes to those that hasten to proceed to every thing. Twofold co-ordinations likewise of the divine genera, are connected with each other, energize together with, and subsist in each other. For the genus of the ruling Gods, is similar and dissimilar to itself, and to other things. But being similar and dissimilar to itself, it conjoins itself to, and separates itself from its principles, preserving the proper boundaries of progression. That, however, which is similar and dissimilar to other things, converts and congregates other things to itself, and separates them from itself. Such, therefore, are the peculiarities of these Gods.
But that the similar and the dissimilar proceed from the demiurgic monad, and the signs which there pre-exist, into this order, Parmenides sufficiently demonstrates to us. For the demiurgic same and different, are the antecedently-existing causes, as he says, of the similitude and dissimilitude in this order. Since, however, though this order of Gods is the summit of the partible genera, and of genera which energize partibly, yet it has a total transcendency with respect to them, in order that being in continuity with the total orders of the Gods, its progression may not be separately allotted its generation from divided causes, but that each of the opposites, as it were, may proceed from the whole demiurgus. For the similar is from same and different, and the dissimilar receives its hypostasis from both these; and thus each participates of the whole demiurgic monad. And this is an indication of total hyparxis, viz. to refer each of the parts that are, as it were different, to the whole. Sameness, therefore, and difference generate similitude; but the one indeed paternally, and the other in an unpolluted manner; and the one generatively, but the other separatively. And again, each constitutes dissimilitude in a manner appropriate to itself. And thus the genera of the assimilative Gods are varied, subsisting as paternal, generative, and collective of wholes. For they are allotted their evolution into light, doubled according to pre-existent causes. And the demiurgic duad energizing through each of the causes that are pre-established in him, makes a progression from each into secondary natures. The whole conclusions, likewise, are dyadic, (or pertaining to the duad) but they are comprehended by the demiurgic tetrad in pre-arranged boundaries. And the multitude of the assimilative progressions is convolved to union, by the simplicity of the intellectual genera.
Each also of the progressions, has indeed one progression supernatural and unknown to the multitude, but the other apparent and known to all. I mean, for instance, that the similar, so far as it is constituted by difference, has a progression from thence difficult to be known; but that so far as it proceeds from sameness, it exhibits a manifest reason of cause. After the same manner, dissimilitude has difference for the manifest principle of its proper hyparxis; but sameness, for its principle difficult to be known. Hence also Parmenides beginning from things unknown to the multitude, and which are alone apparent to science and intellect, ends in things which are known to all men, and are effable. For in the Gods themselves, the ineffable precedes the effable. And the latent and unknown mode of their hypostasis, precedes that which is known according to progression. And thus much concerning these Gods from the Parmenides of Plato.
The Six Books of Proclus, the Platonic Successor, on the Theology of Plato (vol. 2 of 2) · The Wunder Library — complete classics, free to read, with narration.