. . . For Epicurus, an atom did not strictly speaking occupy space; it was simply surrounded by the absence of body.12
If this characterization of Epicurus is right, then the mere existence of atoms does not, after all, entail the existence of open and empty, much less infinite, space. No such amplitude, no such vacuity, is required. To each atom there corresponds only a quite particular place in which it is located at any given moment. The fact that atoms are always moving means only that their places are continually changing. On this view atomic motion does not demand an abiding space that is “a continuous entity subsisting everywhere in the same degree and manner, both where bodies are and where they are not.”13 In short, we can retain the basic Atomist cosmologic that says “if there were no void, there would be no motion; but there is motion; therefore, there is void”14—without having to interpret such a void as continuous or empty, not to say infinite. The void is finite; it is the very place of each and every atom.
Epicurus rejoins Democritus and Leucippus by maintaining that a distinction is to be made between genuinely empty space or “void proper” (as we can call the original sense of void in the phrase “atoms and the void”) and what ought to be termed “vacuum,” that is, an empty part or portion of a compound entity constructed of atoms, for example, an empty stomach in a hungry human being. A vacuum is a form of nonbeing, even a nothing, but it exists within the compound—which in turn exists within the void proper. This is why we can speak intelligibly and not merely oxymoronically of a vacuum as a nonbeing that exists: here the ancient paradox is seen to apply to a more discrete entity. The vacuum exists precisely as a “space-filler” in the apt term of David Sedley, who remarks that a vacuum “occupies some parts of space just as effectively as body occupies others.”15 The Archytian axiom is undisturbed by this claim: for a vacuum exists just to the extent that it has a place in which to exist.16 Void proper—redescribed as “intangible substance” by Epicurus—is what provides such a place, its source as it were. Yet neither void nor vacuum is place in Aristotle’s strict sense of an always already occupied locus for fully formed material objects.17
Nevertheless, Epicurus, unlike Leucippus and Democritus, explicitly identifies void proper with what we must begin to call space. The best account of this momentous step is given by Sextus Empiricus.
Therefore one must grasp that, according to Epicurus, of “intangible substance,” as he calls it, one kind is named “void” (kenon), another “place” (topos), and another “room” (chōra), the names varying according to the different ways of looking at it, since the same substance (phusis) when empty of all body is called “void,” when occupied by a body is named “place,” and when bodies roam through it becomes “room.” But generically it is called “intangible substance” in Epicurus’ school, since it lacks resistant touch.18
This remarkable passage supports the contention that Epicurus was “the first ancient thinker to isolate space in the broadest sense.”19 If Sextus is right, Epicurus does so by positing a generic space—that is, what is coextensive with intangible substance (anaphēs phusis)—and then recognizing at least three roles or functions of such space. “Void” (kenon), true to its sense as “empty,” names the circumstance of unoccupied space; it is tantamount to what I have just called “vacuum.” “Place” (topos) names the situation of occupied space; it refers to the location of a sensible thing in space. The thing thus located in a topos is so far stationary, and to account for the different sense of localization possessed by a moving thing Epicurus posits a third avatar of space: “room” for something to move in. “Room” translates chōra, one of whose affiliated verbs is chōrein, “to go,” especially in the sense of “to roam.”20 From its initial role as matrix in the Timaeus, chōra here becomes a much more delimited power—yet a critical one, since for all the Atomists the primary bodies are in constant motion, a motion that requires room in which to move. Such room, affording leeway to solid objects (atoms, even if imperceptible, are “impassible” magnitudes), is literally voluminous. Aristotle’s confining two-dimensional model of place—two-dimensional insofar as it limits itself to the surfaces of things—is surpassed in a three-dimensional roominess.
Thanks to its considerable dynamism, Epicurean space is the Spielraum of atomic bodies, the very medium of their situatedness and movement, the scene of their multiple occupation. Such space “provides these bodies with location, with the gaps between them, and with room to move.”21 Expansive as such space is—giving place and room for everything—it does not pertain to parts of atoms (assuming that atoms have parts), nor does it exist as intervals among atoms of a given body, nor does it even furnish the very position of a given atom.22 Epicurus might respond that this triple limitation follows from the basic premise that atoms “have no share in the void.”23 Yet if atoms have parts and intervals and positions and if they do indeed exist—and if to exist is to exist in space—then these three aspects of atomic existence will have to be spatially specified. One suspects that Epicurus has not thought through the full implications of his own idea of a sheerly intangible space. If space construed as anaphēs phusis is to be taken seriously, its scope will encompass both the utterly large (the infinite) as well as the utterly small (the infinitesimal), including the most diminutive parts, intervals, and positions.
Lucretius (ca. 99–55 B.C.), Epicurus’s devoted and eloquent disciple, adds this thought: “Whatever will exist will have to be in itself something with extension (augmen), whether large or small, so long as it exists.”24 Here Lucretius is drawing on an entire heritage of thought concerning “extension,” a notion of critical importance in the Hellenistic period. Diastēma, the Greek word for “extension,” implies standing!through (dia- signifies “through,” and stēma derives from the Indo-European root sta-, “stand”) and, more particularly, threading/through (stēmōn means “thread”). To be in space is to stand through it, to stretch through it as a thread might stretch over a surface—except that more than surface is at stake here. The “through” is not only entailed by motion in a void but also is implied in all ways of being spatial.
For Epicurus and Lucretius alike there is an intimate link between the noun “extension,” the preposition “through,” and the concept “space.”25 If placial being is mainly a matter of the “in”—this much we may grant to Aristotle—spatial being is a matter of the “through,” that is, a matter of being “extended,” stretched out such that something exists through the interval or gap that space provides. Instead of being something turned in, en-closed, as in the case of Aristotelian place, space is something turned out; it is something that exists throughout whatever interval is at stake—an interval that can be infinitely large or infinitely small. Atoms may well have a different “order of being,” a different way of existing, than the void proper; the former are essentially plenary, the latter is essentially unoccupied.26 Even so, both atoms and the void must meet certain requirements of existing spatially. These are the requirements of diastemic space as first clearly glimpsed in the Atomism of Epicurus.
II
Some say that chōra is the place of the larger body.
—Sextus Empiricus, Against the Professors
One ancient thinker—not an Atomist but an Aristotelian—thought long and hard about the microphysics of space. I refer to Strato of Lampsacus, the third head of the Peripatetic school, who died ca. 269 B.C. and thus was an exact contemporary of Epicurus. Ancient tradition credits Strato with being the first thinker to proclaim space to be extended in three dimensions, also holding that any part of it always in fact contains a body—even though, in principle, it might not.27 Stobaeus attributes to Strato the following definition: “Place (topos) is the interval in the middle of the container and the contained.”28 At first glance this appears quite Aristotelian, but on closer inspection it turns out that Strato takes place to be something that Aristotle explicitly rejects: the empty pockets found in the interstices of material
