The One-Being becomes Aion once it’s reflected into the Intelligible Realm, the realm immediately after the realm of the One. Aion acts as the source (monad) of the Intelligible Realm, and as the Good, it rules over and unifying Being, Life, and Mind. Specifically, Aion represents a vertical extension of the One into the Intelligible Realm. This means Aion occupies the same ontological place as the One-Being, however, as it exists at the top of the Intelligible Realm rather than at the bottom of the realm of the One, it is functionally different.
Aion is called many things, such as “the Father,” “King of the Universe,” “God of Gods,” “Cause of All,” “The Pre-Essential Demiurge,” “The Paradigm,” “The Idea of Being,” “Supra-Intelligible,” and “Monad from The One.” Aion is beyond Ousia (substance/essence) and beyond On (Being), meaning His existence is beyond all things and prior to the Gods under Him, being alone in the singularity of the highest divinity, governing apart over the universe. Aion is the Pre-Essential Demiurge; and while existing before ousia (substance/Being) is simultaneously the source of ousia and essentiality, which come into existence before the Gods.
He is Supra-Intelligible, meaning He is so sublime and transcendental that even the Gods under Him can’t know Him. He is the source of all essence, and as the source of that which is thought, He is, therefore, the cause of Being; but is still beyond it. As the supreme genus, He allows for all levels of the ontological hierarchy to participate in His divine essence, His principle of intellection thinking the Gods under Him, and Being itself, into existence.
Aion is the creative power the Celestial Demiurge draws from to craft the cosmos. Matter (hylē) is also created by Aion, and is thus eternal. Hylē is initially vacant though, being an empty receptive substance which forms into matter as we know it once the Celestial Demiurge directs the Logoi to give hylē shape. This informs matter and gives it shape, turning it from an empty substance into the matter we understand.
As Aion, the One-Being is the model upon which the Cosmos are based on and is described as the “Essence of Being” from which all Being stems. Aion being the cosmic model is important, because it tells us about the nature of the cosmos; that the cosmos are modelled by the Celestial Demiurge based upon something that is eternal, unchangeable, good, and beyond generation; as Plato quotes in the Timaeus: “Everyone will see that [the Celestial Demiurge] must have looked to the eternal, for the world is the fairest of creations, and He is the best of causes.”
Aion is, as Clarian Apollo says, “Self-begotten, untaught, without a mother, unshakeable, nameless, many-named, and dwelling in fire.” He rules over the Intelligible Realm, holding the role of organizing the Intelligible Realm and all its inhabitants according to the impulses given by the One.
Because Aion comes into being before duality, which sprung when the Word (Logoi) of creation was spoken by the Celestial Demiurge, Iamblichus informs us the only appropriate way to worship Aion is through silence.
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