Space

Space is among the first things we seem to know and among the last we can explain. Every body we touch has its place, every motion runs from one place to another, and the mind can hardly picture anything at all except as spread out before it. Yet when we ask what this spread is, the answers divide sharply. Some say space is a real container. Some call it an order among bodies, others a form of the mind. Still others say it is nothing at all, a mere abstraction from extended things. The idea gathers several neighbouring questions under one head: place and the relation of a thing to what surrounds it, extension and its divisibility, distance and how we perceive it, the bounds or boundlessness of the world, and the void, the vexed question whether there can be space with nothing in it. In the Harvard Classics these questions are not confined to natural philosophers. They arise in confessions, in theology and devotional poetry, in the criticism of drama, in the natural history of species, and even in a treaty fixing a frontier. That range makes space a great idea for these books. It is a concept that every kind of inquiry must reckon with and that none can wholly master.

The question of how space enters knowledge appears early in these books, in a personal form. Augustine recalls that before his conversion he could conceive nothing except as occupying space. Even empty place seemed to him a kind of “spacious nothing”¹. He went further and supposed that whatever was not extended in space must be nothing at all². The confession is valuable because it shows the hold spatial imagination has on thought. Augustine treats this as a habit of mind to be overcome, not as a truth about being, and he later insists that truth is not nothing merely because it is not diffused through space, whether finite or infinite³. With him the question begins as a question about the soul’s capacity: can the mind think what is not spatial?

The moderns turn the question around and ask whether space belongs to things at all, or only to the mind that perceives them. Schiller notes a curious circle. We can determine a place only by reference to absolute space, yet space arises for us only by way of particular places⁴. Carlyle reports, without settling the matter, that Schlegel holds space and time to be mere forms of the mind, while Hope holds them to be incessantly created⁵. The suggestion that space is a form of mind finds its sharpest development in Berkeley. His Philonous argues that the apparent distance and “outness” of objects do not prove they exist outside the mind, since their visible size changes continually as we approach or withdraw⁶. Distance itself, he contends, is a line turned endwise to the eye. It is therefore not immediately perceived by sight but learned from experience⁷. Once it is granted that place and extension exist only in the mind, matter cannot be placed at all, and the notion of an extended material substance loses its footing⁸. Berkeley does not ignore the obvious objection that extended objects would then seem to be contained in an unextended mind. He states that difficulty openly in the dialogue⁹.

Hume takes the doubt in another direction. He does not argue that space is mental. He observes that the idea of space, perfectly clear in common life, yields absurdities when the sciences scrutinize it¹⁰. Berkeley used the analysis of perception to remove matter. Hume uses the analysis of the idea to expose the limits of reason itself. Pascal stands apart from both. He holds that our intuitive knowledge that space has three dimensions is as certain as anything reason demonstrates¹¹. For him the first principles of space, motion and number are known by the heart, not proved. He also insists that these principles hang together: motion cannot exist without space, and space, motion and number are bound in one connected order¹². The contrast is instructive. Where Hume finds the scientific idea of space riddled with paradox, Pascal finds the paradoxes to be a mark of reason’s dependence on intuitions it cannot itself establish.

Those paradoxes concern above all the infinite. In his geometrical writings Pascal argues that space can be increased without end and divided without end, so that it has no indivisible parts¹³. Small and great spaces alike contain infinitely many parts, differing only in the measure of those parts¹⁴. Extension is defined by the separation of parts, so indivisible points, which have no parts, can never compose it, however many are gathered¹⁵. He illustrates the double infinity with a vessel receding seen through a glass. As it draws away its image shrinks continually without ever vanishing into a point, which shows that space can be prolonged and diminished without limit¹⁶. These arguments do not rest on experiment. They rest on the conviction that space, as the mind conceives it, admits no smallest or greatest term.

Schiller approaches the infinite from the side of description. To describe any figure we must limit infinite space¹⁷. Every determinate shape is thus a negation carved out of something boundless. The physicist Kelvin raises the same question in cosmic terms. He asks whether one can really suppose an end of space or of matter, and reflects that light reaches us across space from the remotest stars¹⁸. Even the most precise science of the modern period leaves the question of bounds open. Dante shows the older picture, in which the world has a centre. As his travellers pass the centre of gravity at the bottom of hell their posture reverses, and they climb toward the other hemisphere¹⁹. In his cosmos, up and down are fixed by a real centre. Pascal’s infinite space has no such privileged point.

The thought of the infinite becomes, in Pascal’s Thoughts, a matter of feeling as well as argument. We may enlarge our conceptions beyond every imaginable space and still produce only atoms in comparison with the reality of things²⁰. Man occupies a little space, swallowed up among infinite spaces that know nothing of him²¹. The same sense of disproportion appears in a naturalist’s journal. Darwin, crossing the Pacific, reflects on the immensity of that ocean and on how small the land is compared with the water²². Not every author responds with dread. Lanier’s speaker faces the vast visage of space unafraid, and length and breadth no longer terrify him²³. Between Pascal’s fear and Lanier’s composure lies a question these texts leave open: whether the immensity of space humbles the human spirit or can be met by it.

The oldest physical controversy about space concerns the void. Voltaire, writing for readers who knew the Cartesian physics, reports that Newton proves by experiment that there is no plenum. Newton thereby restores the vacuum that Aristotle and Descartes had banished from the world²⁴. The ancient doctrine held that nature abhors a vacuum, and Pascal mentions this ironically when he speaks of the void as the supposed object of bodies’ dread²⁵. He also takes up the familiar case of an apparently empty box, a stock example in the debate over whether a vessel emptied of visible matter contains anything at all²⁶. The modern position, as Voltaire presents it, is that empty space is real and that the planets move through it unimpeded. Kelvin’s remark that light travels to us from the remotest stars shows how much later physics had to think about what lies between the stars¹⁸. Whether that intervening space is truly empty or filled with some medium is a question that Kelvin’s wave theory of light, by its very title, keeps alive.

The void has also lived in the imagination. Augustine’s “spacious nothing” was a void he could conceive only as a sort of space with nothing in it¹. Milton gives the void a vast poetic body. His Abyss is a dark ocean without bound or dimension, in which length, breadth and height, time and place are all lost²⁷. Into this Satan falls through a vast vacuity ten thousand fathoms deep²⁸. Milton’s Abyss is not the clean empty space of Newton’s physics. It is a chaos where the very dimensions that make space measurable dissolve. The philosophers argue over whether empty space can exist. The poet imagines a region that is neither place nor nothing, and is terrifying because it is both.

The relation of space to God brings together the theological and the metaphysical strands. At the opening of the Confessions Augustine asks whether heaven and earth contain God. If God fills them, does what is left of Him overflow, and is He wholly or only partly present in each place²⁹? The puzzle arises from the very spatial imagination Augustine later renounces, and its resolution leads him to a God present everywhere but not spread through space. The Bhagavad-Gita offers a different image. All things are in the divine as moving air is in measureless space, yet they are not He³⁰. Elsewhere it sees him in every spot of the star-sprinkled space from pole to pole³¹. In one image space is the medium that holds creatures, in the other the field the divine pervades. For Dante the summit of creation lies beyond space altogether. In the highest heaven there is no space and no pole divides³². Space ends where the divine dwelling begins.

Later writers turn this transcendence inward. Emerson holds that the walls of space seem solid to the senses but that the soul abolishes them³³. What Augustine reached by purifying his concept of God, Emerson attributes to the soul’s own intuition. Rossetti, by contrast, keeps the old cosmic architecture as a picture. God’s terrace is built over the depth where space begins, and the earth spins far below like a midge³⁴. Across these authors three positions can be distinguished: God contained by place, God filling all place, and God beyond all place. The texts rarely hold them apart cleanly. Augustine’s question and Dante’s highest sphere suggest that the most adequate view lies in denying that the divine is in space at all.

Place also matters in more ordinary affairs. In the criticism of drama, the unity of place became a rule. Sidney mocks the stage that shows Asia and Africa at once and holds that a play should represent one place³⁵. Johnson attacks the rule. He notes that in Addison’s Cato it confines the whole action to a single hall, producing improprieties³⁶. He traces the unity of place to the presence of Aristotle’s Chorus and judges it dispensable whenever it destroys probability³⁷. In the Preface to Shakespeare he gives his decisive reply. The audience never really takes the stage for Alexandria or Rome³⁸. Since everyone knows the stage is neither Athens nor Sicily but a modern theatre, it can represent first one and then the other³⁹. The dispute turns on what dramatic space is: a literal place that must be preserved, or an imaginative convention the mind freely accepts.

Darwin finds in space an order bearing on the history of life. The areas occupied by species are generally continuous in space, as their endurance is continuous in time⁴⁰. He draws out a parallelism between the distribution of organisms over the earth and their succession through geological time⁴¹. Space here becomes a record, a map of descent. Finally, the treaty with Russia shows space measured and partitioned for human purposes. The boundary of the ceded territory is fixed by latitudes and longitudes, by channels and mountain summits⁴². Here Schiller’s principle that to define we must limit space¹⁷ becomes the practical work of drawing a frontier.

These texts leave the central questions unresolved. Whether space belongs to things or to the mind divides Berkeley, who takes extension into the mind⁸, from those who report its creation or its formal character without deciding⁵. Whether reason can coherently grasp space is denied in Hume’s doubts¹⁰ and partly answered in Pascal’s appeal to intuition¹¹. The void, banished by Aristotle and Descartes and restored by Newton²⁴, still prompts Kelvin to ask about an end of space or matter¹⁸. Above all these, the religious and poetic authors keep pressing a question physics cannot answer: whether the vast space Pascal feared²¹ is the ultimate frame of things, or whether, as Dante³² and Emerson³³ hold, something lies beyond it where space is none.