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 bodies. These pockets riddle such bodies: “Strato of Lampsacus tries to show that the void exists interspersed in every body so that it is not continuous.”29 Places are thus void spaces: “microvoids,” as we might call them. Even if microvoids are never actually vacuous—Atomists’ claims notwithstanding—they are instances of extension at the most elementary level. Microvoids exist not only between container and contained (which for Strato are far less snugly fitting than Aristotle had imagined) but also within a given material body. Hence they pertain to two of the three aspects of atomic extension neglected by Epicurus: interiors and parts of primary bodies. In fact, they are coextensive and isometric with the interiors and parts of actual bodies that fill them. At the limit, the totality of microvoids may even be coextensive with the “cosmic body” that is equivalent to the complete physical universe.30 It is not certain that Strato espoused this extreme position, but he did maintain that any given microvoid is an integral part of cosmic extension and not a mere lacuna in this extension. Hence he managed to put together what Epicurus failed to combine: the extension of the infinitely large and the extension of the infinitesimally small.
Strato also was known in the classical world for having devised the most convincing denial of Aristotle’s notion of natural places, that is, places proper to given elements. According to Strato, every element is heavy and thus falls downward by its sheer weight. If fire and air escape upward, this movement is due to a process of ekthlipsis, that is, being “squeezed” up by the compression of other more forceful elements. By thinking this way, Strato agreed with Epicurus and the earlier Atomists in rejecting the idea of preexisting places in the void. There is indeed differential direction in the void, but this is determined by chance collisions of atoms and not by the power of extant cosmic places.31 And if there are no places carved out of the cosmos in advance, then it is all the more likely that the universe lying beyond the world is something infinitely extended: and this universe is more aptly characterized in spatial rather than placial terms. Just as for Aristotle there is no space apart from place, for Strato there is no place apart from space—no place that is not merely a portion of a much more encompassing whole whose spatiality is both incredibly large and unimaginably small.
If the unimaginably small is a distinctive concern of the Atomists and of Strato, the incredibly large is what increasingly preoccupies ancient philosophers in the wake of Aristotle and Epicurus. One exemplary form of this preoccupation is found in the Stoic proposal that an endless empty void surrounds the finite and place-bound cosmos. The explicit reason for this proposal—which continued to be widely influential