Eternity

Plato inaugurates the Western distinction between time and eternity. In the Timaeus, the Demiurge looks to an eternal pattern (the realm of Forms, which simply is) and fashions a visible cosmos as much like it as possible. But the cosmos must move, and the Forms do not. So the craftsman produces, together with the heavens, "a moving image of eternity, moving according to number." That image is time.

The substance of Plato's eternity is immutable being. Whereas temporal things admit past, present, and future, the eternal admits only "is": it neither came to be nor will cease, neither grows older nor younger, nor is it subject to any of the affections that touch generated things. The Forms do not endure through time; they stand wholly outside the order of becoming. Time is the ordered succession that sensible things require simply to imitate, so far as they can, the self-identity of what truly is.

If eternity and time are two orders of being rather than two stretches of duration, then the sensible world is ontologically derivative, real only insofar as it participates in the unchanging. The philosopher's task is to ascend from the flux of becoming to the eternal, which alone is fully intelligible. Plato also warns against careless usage: we "unconsciously but wrongly" apply tensed language to the eternal essence, as if the Forms had a yesterday or a tomorrow. The distinction between the changeless being of the Forms and the perpetual becoming of sensible things connects the idea of Eternity to the broader questions treated under Being and Change.

Subsequent doctrines of divine eternity, whether Plotinian, Augustinian, Thomist, or Spinozist, tend to begin from this contrast between unchanging being and temporal becoming. The language in which later theologians speak of God as existing "outside time" draws on distinctions Plato drew in the Timaeus.

Aristotle naturalizes eternity and then locates its purest form at the summit of his metaphysics. In Physics VIII he argues that motion can have had no beginning and can have no end: every change presupposes a prior change, and time, as the number of motion, is coextensive with it. The heavens, moving eternally in circles (the only motion that has neither starting-point nor terminus), supply the everlasting frame within which all coming-to-be and passing-away occurs.

But everlasting motion is not the highest eternity. In Metaphysics XII, Aristotle argues that eternal motion requires an eternal unmoved mover, a being of pure actuality without matter or potency. This Prime Mover causes motion not by being pushed but by being loved: it moves the heavens as an object of desire and thought. Its life is energeia, sheer activity, and its activity is thinking itself: "thought thinking thought." Because it has no unrealized potential, it cannot change; because it cannot change, its existence is not strung out in successive moments but wholly and simultaneously itself.

If the world is eternal but unexplained, nothing anchors it; if it has a first moment, time itself becomes paradoxical. Aristotle's solution gives the cosmos permanence without Plato's separated Forms: eternity belongs to an actual being at work, not to an abstract pattern. This reconciliation of eternal being with eternal motion furnished later thinkers, both within the tradition of natural philosophy and within Islamic, Jewish, and Christian theology, with a vocabulary for discussing the eternity of God and the eternity of the world. The question of whether the world's eternity can be demonstrated or must be taken on faith is further considered under the ideas of God and Theology.

Aquinas will argue that Aristotle's arguments for the eternity of the world are not absolutely demonstrative, but will preserve the Prime Mover's eternity as pure actuality. The characterization of God as pure act, timeless, and self-thinking is one that later theologians will draw on, even when they qualify or revise the cosmological arguments that supported it.

Plotinus devotes an entire treatise, Enneads III.7, to disentangling eternity from time. He rejects the easy identification of eternity with mere endless duration. Eternity is not a very long time; it is a life, specifically the life of Intellect (Nous), the second hypostasis, which contemplates the One and possesses itself whole. In this life there is no "was" and no "will be," only an unfragmented "is" in which all intelligible content is present at once.

The substance of the account is the link between eternity and the self-possession of being. Whatever is in time is always reaching out: having been, not yet being, slipping away. The eternal does not reach: it has. Plotinus speaks of eternity as "a life abiding in the same, always having the all present to it." Time, by contrast, is the restlessness of Soul, which cannot hold its being in one grasp and so unfolds it in succession, generating the moving image that Plato described. Time is eternity dispersed; eternity is time gathered up.

For Plotinus, lower grades of being are marked by greater dispersion; higher grades, by greater unity. Eternity is thus not a property added to Intellect from without but the very form of its existence, and it points beyond itself to the One, which is above even eternity because above multiplicity. This graded account of being provided later theologians with a vocabulary for distinguishing God's mode of existence from the world's, a vocabulary taken up by Augustine and developed further by Aquinas. The question of how different levels or grades of being stand in relation to one another is treated more fully under the ideas of Being and God.

Augustine draws heavily on Plotinus in developing his account of divine eternity, but the Christian context creates a difficulty Plotinus did not face: the eternal God of the Enneads does not create freely out of love but overflows by necessity. Augustine must argue that a God who is truly eternal can nonetheless freely choose to create time, a problem that does not arise within Plotinus's system.

Augustine brings Plotinus into Christian theology and uses him to answer a taunt: "What was God doing before He made heaven and earth?" The question is illicit, Augustine replies, because it presupposes a time before time. God did not exist for countless ages and then decide to create. God's mode of being is not duration at all. "In the beginning" does not locate creation within a pre-existing time; it inaugurates time together with the creature.

The substance of Augustine's eternity is the changeless present. In Confessions XI he addresses God directly: "Thy years neither come nor go; whereas ours both come and go, that they all may come. Thy years are one day; and Thy day is not daily, but To-day." Past and future belong to finite minds that hold their lives together only through memory and expectation. God, who needs no such stitching, possesses the whole of His being in a single undivided act. Time is therefore not God's medium but His creature; eternity is not infinite time but time's absolute other.

If God were in time, then creation would be an event in God's life, raising the question of what came before. If God is eternal in Augustine's sense, creation is the production of time as such, and the question "before creation" dissolves, since there was no time in which to be before. The doctrine also bears on divine providence: a God who holds all moments simultaneously can know and will the entire temporal sweep without before or after. The relation between divine eternity and human time is further considered under the ideas of God and Time.

Augustine brings the Plotinian account of eternity as the timeless present into Christian theology and transmits it to the Latin Middle Ages. Aquinas will refine the formulation, but a tension in Augustine's account remains: if God possesses all moments simultaneously, how can God freely will one course of events over another, or freely choose to create rather than not to create?

Aquinas gives the Latin tradition its most precise formula for eternity. Adopting Boethius's definition, he writes that eternity is "the simultaneously-whole and perfect possession of interminable life" (interminabilis vitae tota simul et perfecta possessio). Every term does work. "Interminable" excludes beginning and end. "Whole" and "simultaneous" exclude succession. "Possession" and "life" mark it as the act of a living being, not a static abstraction.

The substance is the rigorous separation of two meanings of "eternal" that Aquinas refuses to collapse. Even if the world had always existed, as Aristotle's arguments suggest, it would still not be eternal in God's sense, because its being would unfold successively. "The divine being is all being simultaneously without succession, but with the world it is otherwise." Eternity thus measures the being of the immutable in the way time measures motion. Between eternity and time Aquinas places aeviternity, the measure of creatures (angels, heavenly bodies) that have beginnings but no intrinsic succession in their substantial being.

Because God stands outside the temporal flow, Aquinas argues that He knows all contingent futures not as future but as present to His single gaze, like a man on a watchtower who sees all travelers on the road at once. Aquinas also uses the distinction between eternity and endless duration to address the controversy over whether the world is eternal: creation does not require a temporal first moment but only metaphysical dependence on God, and faith alone, not philosophical demonstration, teaches that the world had a beginning. The problem of how God's eternal knowledge is compatible with contingent human action is further considered under the ideas of God, Fate, and Will.

Aquinas's threefold scheme of eternity, aeviternity, and time, together with the tota simul formula, became the standard scholastic account. Leibniz will argue that God's eternal survey of all possibles is compatible with genuine free choice; Kant will deny that any theoretical account of eternity can be more than a regulative idea the mind projects beyond its proper domain of experience.

Dante turns scholastic doctrine into vision. The Paradiso climbs through the nine moving heavens into the Empyrean, the motionless heaven of pure light and love that is not a place in space but the mind of God. There, in Canto XXVIII, the pilgrim sees a single infinitesimal point of intense light around which nine concentric rings of angels wheel. That point is God's eternity made imaginable: the dimensionless center from which all temporal circumference radiates.

The substance is the poetic enactment of the tota simul. In the lower heavens, time is scattered; the blessed souls appear in successive spheres according to their virtues. But as Dante ascends, succession collapses. In the Empyrean the whole hierarchy stands revealed at once, and in the final cantos the pilgrim gazes into the divine light and sees, bound "in one volume," what is scattered throughout the universe: substance and accident, past and future, all held together by love. The vision is simultaneous because its object is eternal; the poet's difficulty in reporting it registers the gap between human memory, strung out in time, and the eternal single act it tried to see.

For Dante, salvation is not an endless extension of temporal life but participation in God's own mode of being: to be saved is to share, as creatures can, in the standing now. Hell and Purgatory still know duration and change; Heaven, properly speaking, does not. The Paradiso is thus a cosmology in which physics gives way to metaphysics and metaphysics to the beatific vision, a vision that the poem can approach but not fully articulate, since its object is by definition beyond time and therefore beyond narrative. The question of what the soul's final state involves is treated more fully under the ideas of Immortality and God.

Dante attempts to give the scholastic eternity imaginative rather than merely conceptual form. That the effort breaks down at the poem's end, where memory fails and language can no longer follow, is itself a precise rendering of what the tota simul implies for a finite mind that lives in time and can only glimpse, not possess, the simultaneous whole.

Hobbes takes up eternity as a test case in his larger campaign against scholastic metaphysics. In Chapter 46 of Leviathan he singles out the doctors who insist that eternity does not mean an endless succession of time but rather "the standing still of the present time, a Nunc-stans." This phrase, he holds, corresponds to nothing that can be imagined and therefore conveys nothing intelligible. What the schools offer as the highest conception of divine being he treats as jargon produced by compounding words into combinations that answer to no possible image. The point is not merely that the doctrine is false; it is that its terms fail to signify.

The substance of the objection follows from Hobbes's nominalism and his materialist account of thought. Names stand for conceptions, and every conception derives ultimately from sense. A Nunc-stans would be a present moment that does not pass, a duration with no before and no after. Hobbes finds this no more intelligible than a Hic-stans, a place that occupies an infinite extent while having no parts outside one another. If "eternity" is to retain any philosophical use, it can only denote duration without beginning and without end. The same treatment is given to "separated essences," "incorporeal substance," and the other abstractions by which the schools were thought to have populated a realm beyond body and motion.

Hobbes's treatment of divine eternity is therefore austere and agnostic. God is to be worshipped, not comprehended, and the honorific predicates applied to him are acts of submission rather than propositions about an inner divine nature. Eternity in this restricted usage marks only the interminable duration of the first cause, not a mode of being set against the temporal. The controversy over whether a philosophical theology can use terms like "substance" or "eternity" of a being whose object cannot be imagined is further considered under the ideas of God, Metaphysics, and Language.

Locke will press a milder version of this empiricist challenge, allowing that we form an idea of infinite duration by adding one moment to another while granting that we can scarcely conceive duration without succession, even when we apply the word to God. Later philosophers who wish to preserve the scholastic sense of eternity must answer the Hobbesian demand that its terms be redeemed in something more than words.

Spinoza redefines eternity by severing it from duration entirely. In the Ethics, Definition 8 of Part I states: "By eternity I understand existence itself, so far as it is conceived necessarily to follow from the definition alone of the eternal thing." Eternity is not a very long time, nor even timelessness understood as time's negation. It is the modality of necessary existence. Whatever exists because its essence involves existence (God, or Substance) is eternal by that very fact.

The substance of Spinoza's account lies in the phrase sub specie aeternitatis, "under the aspect of eternity." Things can be conceived in two ways: as actual in relation to a fixed time and place, or as contained in God and following from the necessity of the divine nature. Only the second way is genuinely eternal. The first gives the imagination, the second gives reason and intellect. The highest knowledge (scientia intuitiva in Part V) grasps particular things as eternal modes of God's attributes. When the mind achieves this, it itself becomes, in part, eternal: "We feel and know by experience that we are eternal."

Spinoza's blessedness is not a posthumous reward but a present condition of the mind that achieves adequate knowledge: the intellectual love of God, in which the mind participates in God's own self-knowledge. This love is eternal because its object is. The distinction between time and eternity thus names two different cognitive postures toward the same reality: imagination apprehends a world of perishing singulars, while reason and the highest knowledge apprehend a single infinite system in which nothing, strictly speaking, perishes or comes to be. The implications of this account for the question of immortality are considered under that idea.

Spinoza's account severs eternity from the personal God of medieval theology and locates it within a single immanent substance. Hegel will accept much of this framework but argue that a substance without genuine development in time is insufficiently infinite; the Absolute, for Hegel, must achieve itself through history rather than merely be contemplated from outside it.

Locke approaches eternity through the theory of ideas. In Book II of the Essay, he argues that our idea of time arises from the mind's reflection on the succession of its own thoughts, and that duration is abstracted from this experience. From any finite span we pass to the idea of a greater span, and so on indefinitely, until we reach the notion of an endless or infinite duration. This is the route to eternity considered as interminable time, and Locke treats it as exactly parallel to the way we form the ideas of infinite space and infinite number. Eternity, in its first meaning, is recovered by the empiricist's own method.

The substance of his analysis lies in the distinction between positive and negative elements in this idea. We have a clear and positive conception of each particular length and of greater lengths than any we have yet reached. What we do not have is any positive grasp of the infinite itself, which remains for us only the idea of "so much greater as cannot be comprehended." Whatever lies beyond our positive idea, Locke writes, "lies in obscurity, and has the indeterminate confusion of a negative idea." His point is not that eternity is meaningless but that its content exceeds the finite capacity of the human mind, and must be held in an essentially negative manner. The word names a limit that our thought approaches without ever reaching.

With regard to the second traditional sense of eternity, the timeless immutability of the scholastic tradition, Locke is considerably more reserved. Duration without succession, he confesses, is "nothing more inconceivable" to him than any other notion the schools have produced. Yet he does not quite join Hobbes in dismissing the scholastic doctrine outright. He grants that we can "easily conceive in God infinite duration," and describes God's knowledge as embracing all things past and to come as though they were present. Readers have debated whether this concession approaches the tota simul of Aquinas or whether Locke still conceives God's duration as successive and merely unbounded. The broader question of how experience can yield any idea of the infinite at all is further considered under the ideas of Infinity and Knowledge.

Locke's empiricist analysis fixes the Enlightenment terms of the eternity question. Leibniz will reply in the New Essays that the eternal truths residing in God's understanding cannot be reduced to endlessly extended duration, and Kant will later transform the antinomy of the infinite past into a diagnosis of reason's own limits. The question Locke bequeaths to both is whether a mind confined to the succession of its ideas can think the timeless at all.

Leibniz restores the classical theistic eternity against Spinoza's necessitarian version. For Leibniz, God is an eternal, necessary being whose intellect contains the infinity of possible worlds and whose will selects, by the principle of sufficient reason, the best of them for creation. Eternity here means both necessary existence and the non-temporal vantage of the divine understanding, which surveys all compossibilities in a single act.

The substance of Leibniz's eternity lies in his doctrine of possibility. The eternal truths (mathematical, logical, metaphysical) subsist in God's understanding prior to and independently of His will; they are necessary because their opposites involve contradiction. But contingent truths, including the whole temporal unfolding of this world, are eternally seen by God though not eternally necessary. Each monad carries within itself the law of its entire series, and God, contemplating this infinite harmony from eternity, chose to actualize it because of its maximal perfection. Time belongs to the monads; God's comprehension of time does not.

Against Spinoza, Leibniz insists that God's choice was genuinely free, since an alternative world was logically possible, even if God's reasons for choosing this one were sufficient. Against those who would make divine will arbitrary, he insists that eternal truths bind God's wisdom even when they do not compel His will. The eternal thus mediates between blind necessity and arbitrary caprice, naming that order of intelligibility within which rational choice, divine or human, can be exercised at all. The question of how divine foreknowledge and human freedom are to be reconciled is further considered under the ideas of Fate and Will.

Leibniz's account attempts to combine the eternity and rationality of the Thomistic God with a genuine doctrine of divine freedom. Kant will examine whether such claims, however internally coherent, can be warranted by any form of theoretical reasoning.

Kant turns the eternity question into a test case for critical philosophy. In the Transcendental Dialectic, the first antinomy stages a contradiction: reason can prove with equal force that "the world has a beginning in time" and that "the world has no beginning, but is infinite in respect both to time and space." Cogent arguments on both sides show, in Kant's view, that the reasoning is not demonstrative but dialectical, illusory. The cosmological question of eternity exceeds the bounds of possible experience and cannot be settled by speculative reason at all.

The substance of Kant's move is to diagnose the illusion rather than pick a side. Time and space are forms of our sensibility, not features of things in themselves. To ask whether the world as a thing in itself has an infinite or finite temporal past is to mistake the conditions of appearance for properties of the real. The antinomies thus do not refute reason; they disclose its proper limits. Neither the eternity nor the beginning of the world can be an object of theoretical cognition.

The argument has consequences for practical reason. In the second Critique, Kant argues that the moral law commands the pursuit of holiness, which no finite being can attain in finite time. The soul is therefore required to postulate "an endless duration of its existence," an immortality that is not the tota simul of the scholastics but an infinite progress in time. Eternity here is neither timeless presence nor settled beatitude but the unending moral striving of a will that can never fully arrive. The connection between eternity, immortality, and the demands of the moral law is further considered under the ideas of Immortality and Duty.

Kant's critical philosophy treats the medieval eternal God as a regulative idea rather than a theoretical object and replaces the beatific vision with the postulate of endless moral progress. Several thinkers in the nineteenth century, Hegel most prominently, will argue that this account of eternity as a merely regulative projection fails to do justice to the reality of the Absolute.

Hegel rejects the received opposition between time and eternity. To place the eternal in a "beyond" outside history is, for him, to worship an abstraction and to leave the actual world godless. The true eternal is not timeless in the sense of being against time; it is the concrete universal that realizes itself in and through time. Spirit (Geist) is eternal precisely because it achieves itself as the inner truth of every temporal moment.

The substance is Hegel's refashioning of the nunc stans as the living present. In the Philosophy of Nature he writes that the truth of time is the present, which is neither the vanished past nor the not-yet future but the eternal self-relation of Spirit, which holds both together. History is not the opposite of eternity but its theater. The Idea unfolds its moments (Oriental, Greek, Roman, Germanic), and in each stage Spirit becomes more fully what it already eternally is. What looks from outside like succession is from within the self-articulation of a single eternal content.

Where Kant posits an endless progress toward an unreachable ideal, Hegel insists that the Absolute is genuinely attained in time: in religion as representation and in philosophy as concept. Where Spinoza has a static substance surveyed from without, Hegel's eternal is a living, self-developing subject immanent in history. Eternity on this view is not a beyond but a depth, apprehended by reason when it has reconciled itself with what actually is. The broader question of how history stands in relation to rational or divine purpose is treated under the ideas of History and Progress.

In Hegel's account, eternity ceases to be the opposite of time and becomes instead its inner truth. The question of whether the Absolute is best understood as timeless or as self-realizing in history is one that subsequent idealist and theological thinkers have continued to debate.