Timaeus
The Demiurge and World Soul (28a)
Timaeus: and has no Becoming? And what is that which is Becoming always and never is Existent? Now the one of these is apprehensible by thought with the aid of reasoning, since it is ever uniformly existent; whereas the other is an object of opinion with the aid of unreasoning sensation, since it becomes and perishes and is never really existent. Again, everything which becomes must of necessity become owing to some Cause; for without a cause it is impossible for anything to attain becoming. But when the artificer of any object, in forming its shape and quality, keeps his gaze fixed on that which is uniform, using a model of this kind, that object, executed in this way, must of necessity
The Intellectual-principle, the Ideas, and the Authentic Existence (10)
All, then, that is present in the sense realm as Idea comes from the Supreme. But what is not present as Idea, does not. Thus of things conflicting...
(10) All, then, that is present in the sense realm as Idea comes from the Supreme. But what is not present as Idea, does not. Thus of things conflicting with nature, none is There: the inartistic is not contained in the arts; lameness is not in the seed; for a lame leg is either inborn through some thwarting of the Reason-principle or is a marring of the achieved form by accident. To that Intellectual Kosmos belong qualities, accordant with Nature, and quantities; number and mass; origins and conditions; all actions and experiences not against nature; movement and repose, both the universals and the particulars: but There time is replaced by eternity and space by its intellectual equivalent, mutual inclusiveness.
In that Intellectual Kosmos, where all is one total, every entity that can be singled out is an intellective essence and a participant in life: thus, identity and difference, movement and rest with the object resting or moving, essence and quality, all have essential existence. For every real being must be in actuality not merely in potentiality and therefore the nature of each essence is inherent in it.
This suggests the question whether the Intellectual Kosmos contains the forms only of the things of sense or of other existents as well. But first we will consider how it stands with artistic creations: there is no question of an ideal archetype of evil: the evil of this world is begotten of need, privation, deficiency, and is a condition peculiar to Matter distressed and to what has come into likeness with Matter.
Time and Eternity (6)
Now the Principle this stated, all good and beauty, and everlasting, is centred in The One, sprung from It, and pointed towards It, never straying...
(6) Now the Principle this stated, all good and beauty, and everlasting, is centred in The One, sprung from It, and pointed towards It, never straying from It, but ever holding about It and in It and living by Its law; and it is in this reference, as I judge, that Plato- finely, and by no means inadvertently but with profound intention- wrote those words of his, "Eternity stable in Unity"; he wishes to convey that Eternity is not merely something circling on its traces into a final unity but has Being about The One as the unchanging Life of the Authentic Existent. This is certainly what we have been seeking: this Principle, at rest within rest with the One, is Eternity; possessing this stable quality, being itself at once the absolute self-identical and none the less the active manifestation of an unchanging Life set towards the Divine and dwelling within It, untrue, therefore, neither on the side of Being nor on the side of Life- this will be Eternity .
Truly to be comports never lacking existence and never knowing variety in the mode of existence: Being is, therefore, self-identical throughout, and, therefore, again is one undistinguishable thing. Being can have no this and that; it cannot be treated in terms of intervals, unfoldings, progression, extension; there is no grasping any first or last in it.
If, then, there is no first or last in this Principle, if existence is its most authentic possession and its very self, and this in the sense that its existence is Essence or Life- then, once again, we meet here what we have been discussing, Eternity.
Observe that such words as "always," "never," "sometimes" must be taken as mere conveniences of exposition: thus "always- used in the sense not of time but of incorruptibility and endlessly complete scope- might set up the false notion of stage and interval. We might perhaps prefer to speak of "Being," without any attribute; but since this term is applicable to Essence and some writers have used the word "Essence" for things of process, we cannot convey our meaning to them without introducing some word carrying the notion of perdurance.
There is, of course, no difference between Being and Everlasting Being; just as there is none between a philosopher and a true philosopher: the attribute "true" came into use because there arose what masqueraded as philosophy; and for similar reasons "everlasting" was adjoined to "Being," and "Being" to "everlasting," and we have "Everlasting Being." We must take this "Everlasting" as expressing no more than Authentic Being: it is merely a partial expression of a potency which ignores all interval or term and can look forward to nothing by way of addition to the All which it possesses. The Principle of which this is the statement will be the All-Existent, and, as being all, can have no failing or deficiency, cannot be at some one point complete and at some other lacking.
Things and Beings in the Time order- even when to all appearance complete, as a body is when fit to harbour a soul- are still bound to sequence; they are deficient to the extent of that thing, Time, which they need: let them have it, present to them and running side by side with them, and they are by that very fact incomplete; completeness is attributed to them only by an accident of language.
But the conception of Eternity demands something which is in its nature complete without sequence; it is not satisfied by something measured out to any remoter time or even by something limitless, but, in its limitless reach, still having the progression of futurity: it requires something immediately possessed of the due fullness of Being, something whose Being does not depend upon any quantity but subsists before all quantity.
Itself having no quantity, it can have no contact with anything quantitative since its Life cannot be made a thing of fragments, in contradiction to the partlessness which is its character; it must be without parts in the Life as in the essence.
The phrase "He was good" refers to the Idea of the All; and its very indefiniteness signifies the utter absense of relation to Time: so that even this Universe has had no temporal beginning; and if we speak of something "before" it, that is only in the sense of the Cause from which it takes its Eternal Existence. Plato used the word merely for the convenience of exposition, and immediately corrects it as inappropriate to the order vested with the Eternity he conceives and affirms.