On Time

Why Read These Three Together?

The link is not coincidence but lineage. Heidegger studied under Husserl at Freiburg, became his assistant, and in 1928 succeeded him in the chair of philosophy; Being and Time (1927) is dedicated to Husserl "in friendship and admiration." Yet Heidegger's entire mature project is also a running argument with ancient Greek philosophy — above all Plato and Aristotle — over how the West first came to think of time at all, and, he argues, first came to think of it badly.

Plato's Timaeus gives the founding Western account of time as a cosmological, mathematical order — modeled on eternity, measured by the heavens. Husserl, twenty-two centuries later, brackets that entire cosmological question and asks a narrower, more radical one: never mind the heavens — how is time first constituted, moment by moment, in the stream of experience itself? Heidegger, Husserl's own student, then reopens the biggest question of all: what if time is not primarily a feature of the cosmos or of consciousness, but the very horizon within which anything can be said "to be"? Read in sequence, the three form a compressed history of Western thinking about time: cosmic, then subjective, then ontological.

The Timaeus and Its CosmologyPlato's only sustained account of nature

Written around 360 BCE, the Timaeus is Plato's sole extended venture into cosmology and natural philosophy, delivered mostly as a continuous speech by the Pythagorean-inflected title character. Plato frames the whole account modestly, as a eikōs mythos — a "likely story" — since anything said about the changing physical world can, at best, approximate the certainty available about the eternal Forms.

The dialogue divides reality into two fundamental kinds, later joined by a third. Being is eternal, unchanging, and grasped by reason alone — the realm of the Forms, the perfect models of Justice, Circle, Animal, and so on. Becoming is the visible, changing world grasped by perception and opinion — a copy, always in flux, of that eternal model. Between them Plato places the chōra — the Receptacle, a formless "nurse of becoming" in which images of the Forms flicker into being, roughly anticipating what later philosophy would call space or matter.

A divine craftsman, the Dēmiourgos (Demiurge), orders this pre-existing chaos by looking to the eternal Forms as a template and imposing mathematical proportion upon it — famously constructing the four elements from regular geometric solids. Being good, and wanting his creation to resemble its eternal model as closely as a created thing possibly can, the Demiurge faces a problem: the model itself is eternal, but nothing that comes to be can itself be eternal. His solution is time.

Eternity and the Moving Imageαἰών and χρόνος

Since the created cosmos could not itself be eternal, the Demiurge fashions time (chronos) as "a moving image of eternity" (aiōn) — a likeness that proceeds according to number, imitating eternity's unity by unfolding as an ordered, countable succession rather than remaining fixed in a single, unmoving now. Where eternity simply is, abiding "in one" without before or after, time moves — but moves in a regular, mathematically ordered way, so that it can still mirror, however imperfectly, the perfection of its eternal model.

"Time and the heaven came into being at the same instant." Plato, Timaeus 38b (paraphrased from the standard English rendering)

This has a striking consequence: there was no time before the ordered cosmos, because time is created together with the heavens (ouranos) as one of its features, not as a pre-existing container the cosmos is dropped into. Plato is careful — almost fussily so — to note that it is strictly improper to speak of a "before" the cosmos at all, since "before" and "after" are themselves temporal words, and using them to describe what preceded time generates nonsense. Whatever chaotic motion existed prior to divine ordering, it existed in no time properly speaking.

Measuring Time in the Heavens

If time is to be an ordered, countable image of eternity, something must mark and measure its passage. Plato assigns this role to the heavenly bodies: the sun, moon, and five visible planets are created specifically as instruments so "that time might be distinctly marked" — their regular revolutions divide the flow of time into countable units: days and nights (the rotation of the heavens), months (the moon's cycle), and years (the sun's cycle). A "perfect year" (later writers call it the "Great Year") occurs when all these celestial cycles simultaneously return to their starting alignment.

Aristotle, Plotinus, AugustineThe idea travels

Aristotle, Plato's student, kept the link between time and motion but stripped away the mythic creation-story: in the Physics, he defines time as "the number of motion in respect of before and after," treats time as everlasting rather than created, and ties its reality closely to the nyn — the "now" — as the boundary-point between past and future, raising a puzzle (still discussed today) over whether time is fully real without a mind able to count.

Plotinus, in the third century CE, reworked the eternity–time relation in explicitly psychological terms: time, for him, is generated by a kind of restlessness in Soul — its own discursive, unfolding activity — a "falling away" from the undivided fullness of eternity into successive moments, edging philosophy a step closer to locating time in something like a subject rather than purely in the heavens.

Augustine, in the Confessions (Book XI, c. 397–400 CE), completes that shift. Famously admitting he does not know what time is the moment he tries to explain it, Augustine relocates time almost entirely into the soul: past and future have no being in themselves — only a present memory of the past and a present expectation of the future — so that time becomes a distentio animi, a "distension" or stretching of the mind. This is the decisive bridge: over a millennium before Husserl, Augustine had already turned the question of time inward, from the heavens to the experiencing soul.

The Subjective TurnFrom the heavens to the living present

Edmund Husserl (1859–1938) inherits the Augustinian turn and radicalizes it into a full method. Where Plato asks how the cosmos measures out time, and Aristotle asks how motion is counted, Husserl brackets both questions. In his lectures on Internal Time-Consciousness (delivered from 1905, edited and published in 1928), he asks a narrower and, in his view, more fundamental question: setting aside physics and cosmology entirely, how is the experience of duration, succession, and change first built up — konstituiert — within the flowing present of consciousness itself?

This is phenomenology's signature move applied to time: not "what is time, out there," but "how is time given, in here" — as a structure of lived experience that must already be in place before any clock, calendar, or celestial cycle can be experienced as measuring anything at all.

Retention, Primal Impression, Protention

Husserl's guiding example is hearing a melody. A melody is only heard as a melody — not a senseless string of disconnected tones — because each new tone is experienced together with the tones just past and those about to come. He analyzes this "living present" into three inseparable moments:

Time, on this account, is not a sequence of isolated instants strung together afterward, but a single flowing structure — thick, not knife-edged — that is the condition for experiencing melody, motion, and the very unity of one's own consciousness across time. (A full interactive treatment of this structure, and of Husserl's phenomenological method more broadly, is developed in the companion guide, Phenomenology & Edmund Husserl.)

Dasein's Ecstatic TemporalityBeing and Time, 1927

Martin Heidegger (1889–1976) was Husserl's assistant at Freiburg and, in 1928, his successor to the chair. Being and Time (Sein und Zeit, 1927) both extends and breaks from Husserl's phenomenology. Its central wager: the age-old question "what does it mean to be?" can only be answered by first analyzing Dasein — the being for whom its own being is always an issue — and the ultimate horizon against which Dasein's being becomes intelligible is time, specifically Dasein's own Zeitlichkeit (temporality).

Heidegger describes this temporality as ecstatic: Dasein does not sit inside a series of now-points but continually "stands outside itself" in three unified dimensions, or ecstases:

The future takes priority because Dasein's ownmost, most certain, yet radically indefinite possibility is its own death. Authentic temporality, for Heidegger, is grounded in vorlaufende Entschlossenheit — "anticipatory resoluteness," a running-ahead toward death that individualizes Dasein and discloses its whole potentiality-for-being, rather than dissolving into the anonymous, endlessly-postponing "they" (das Man) of everyday life.

Against the "Vulgar" Concept of Time

In section 81 of Being and Time, Heidegger turns directly on the tradition running from Aristotle onward — a tradition his own reading of the Timaeus and the Physics places Plato at the head of — and argues that ordinary, everyday, and even most philosophical and scientific conceptions of time reduce it to an infinite, homogeneous succession of discrete "now-points," each indifferent to the others, in principle reversible, measurable, and countable, much as Aristotle's definition already implies.

Heidegger does not deny this "vulgar" (ordinary) conception describes something real — clock-time, calendar-time, the time of physics is genuine and useful. His claim is that it is derivative: it covers over, and is only possible on the basis of, the more primordial ecstatic temporality of Dasein described above. A now-point can only be encountered as a "now" — rather than nothing at all — because Dasein already temporalizes itself ecstatically, making-present against a horizon of having-been and coming-toward. Strip away that ecstatic structure, and there is no "now" for anyone to count in the first place.

Time and Being — Es GibtZeit und Sein, the 1962 lecture

Heidegger came to think that Being and Time's own project — deriving the meaning of Being from Dasein's temporality — remained too anchored in a subject-centered, quasi-transcendental framework, not unlike the very Husserlian starting point he had set out to move beyond. In the 1962 lecture Zeit und Sein ("Time and Being," published in On Time and Being), he attempts something more radical still.

Rather than asking what Being is or what Time is — treating each as though it were some kind of entity — Heidegger asks after the "It" hidden in two ordinary German phrases: Es gibt Sein ("It gives Being") and Es gibt Zeit ("It gives Time"). Neither Being nor Time is itself a being; each is rather something granted, given, by an anonymous "giving" (das Geben) that Heidegger names Ereignis — the "event of appropriation," the way Being and Time belong together and are handed over jointly, without any further ground standing behind the giving itself.

"Es gibt Sein. Es gibt Zeit." Heidegger, Zeit und Sein, 1962

This is Heidegger's final attempt to think time without falling back into either Plato's cosmological image or his own earlier reliance on Dasein's temporalizing — a step, as he puts it, out of metaphysics' habitual question about the Being of beings, toward thinking the giving that lets there be Being and Time at all.

Three Models of Time

Toggle between the three accounts to see how each locates time in a different place entirely: the celestial heavens, the flowing present of consciousness, or the finite, forward-straining structure of existence itself.

Comparative Table

Conceptual Lineage

Glossary