Now come: I will untangle for thy steps Now by what motions the begetting bodies Of the world-stuff beget the varied world, And then forever resolve it when begot, And by what force they are constrained to this, And what the speed appointed unto them Wherewith to travel down the vast inane: Do thou remember to yield thee to my words. For truly matter coheres not, crowds not tight, Since we behold each thing to wane away, And we observe how all flows on and off, As 'twere, with age-old time, and from our eyes How eld withdraws each object at the end, Albeit the sum is seen to bide the same, Unharmed, because these motes that leave each thing Diminish what they part from, but endow With increase those to which in turn they come, Constraining these to wither in old age, And those to flower at the prime (and yet Biding not long among them). Thus the sum Forever is replenished, and we live As mortals by eternal give and take. The nations wax, the nations wane away; In a brief space the generations pass, And like to runners hand the lamp of life One unto other. But if thou believe That the primordial germs of things can stop, And in their stopping give new motions birth, Afar thou wanderest from the road of truth. For since they wander through the void inane, All the primordial germs of things must needs Be borne along, either by weight their own, Or haply by another's blow without. For, when, in their incessancy so oft They meet and clash, it comes to pass amain They leap asunder, face to face: not strange— Being most hard, and solid in their weights, And naught opposing motion, from behind. And that more clearly thou perceive how all These mites of matter are darted round about, Recall to mind how nowhere in the sum Of All exists a bottom,—nowhere is A realm of rest for primal bodies; since (As amply shown and proved by reason sure) Space has no bound nor measure, and extends Unmetered forth in all directions round. Since this stands certain, thus 'tis out of doubt No rest is rendered to the primal bodies Along the unfathomable inane; but rather, Inveterately plied by motions mixed, Some, at their jamming, bound aback and leave Huge gaps between, and some from off the blow Are hurried about with spaces small between. And all which, brought together with slight gaps, In more condensed union bound aback, Linked by their own all inter-tangled shapes,— These form the irrefragable roots of rocks And the brute bulks of iron, and what else Is of their kind... The rest leap far asunder, far recoil, Leaving huge gaps between: and these supply For us thin air and splendour-lights of the sun. And many besides wander the mighty void— Cast back from unions of existing things, Nowhere accepted in the universe, And nowise linked in motions to the rest. And of this fact (as I record it here) An image, a type goes on before our eyes Present each moment; for behold whenever The sun's light and the rays, let in, pour down Across dark halls of houses: thou wilt see The many mites in many a manner mixed Amid a void in the very light of the rays, And battling on, as in eternal strife, And in battalions contending without halt, In meetings, partings, harried up and down. From this thou mayest conjecture of what sort The ceaseless tossing of primordial seeds Amid the mightier void—at least so far As small affair can for a vaster serve, And by example put thee on the spoor Of knowledge. For this reason too 'tis fit Thou turn thy mind the more unto these bodies Which here are witnessed tumbling in the light: Namely, because such tumblings are a sign That motions also of the primal stuff Secret and viewless lurk beneath, behind. For thou wilt mark here many a speck, impelled By viewless blows, to change its little course, And beaten backwards to return again, Hither and thither in all directions round. Lo, all their shifting movement is of old, From the primeval atoms; for the same Primordial seeds of things first move of self, And then those bodies built of unions small And nearest, as it were, unto the powers Of the primeval atoms, are stirred up By impulse of those atoms' unseen blows, And these thereafter goad the next in size: Thus motion ascends from the primevals on, And stage by stage emerges to our sense, Until those objects also move which we Can mark in sunbeams, though it not appears What blows do urge them. Herein wonder not How 'tis that, while the seeds of things are all Moving forever, the sum yet seems to stand Supremely still, except in cases where A thing shows motion of its frame as whole. For far beneath the ken of senses lies The nature of those ultimates of the world; And so, since those themselves thou canst not see, Their motion also must they veil from men— For mark, indeed, how things we can see, oft Yet hide their motions, when afar from us Along the distant landscape. Often thus, Upon a hillside will the woolly flocks Be cropping their goodly food and creeping about Whither the summons of the grass, begemmed With the fresh dew, is calling, and the lambs, Well filled, are frisking, locking horns in sport: Yet all for us seem blurred and blent afar— A glint of white at rest on a green hill. Again, when mighty legions, marching round, Fill all the quarters of the plains below, Rousing a mimic warfare, there the sheen Shoots up the sky, and all the fields about Glitter with brass, and from beneath, a sound Goes forth from feet of stalwart soldiery, And mountain walls, smote by the shouting, send The voices onward to the stars of heaven, And hither and thither darts the cavalry, And of a sudden down the midmost fields Charges with onset stout enough to rock The solid earth: and yet some post there is Up the high mountains, viewed from which they seem To stand—a gleam at rest along the plains. Now what the speed to matter's atoms given Thou mayest in few, my Memmius, learn from this: When first the dawn is sprinkling with new light The lands, and all the breed of birds abroad Flit round the trackless forests, with liquid notes Filling the regions along the mellow air, We see 'tis forthwith manifest to man How suddenly the risen sun is wont At such an hour to overspread and clothe The whole with its own splendour; but the sun's Warm exhalations and this serene light Travel not down an empty void; and thus They are compelled more slowly to advance, Whilst, as it were, they cleave the waves of air; Nor one by one travel these particles Of the warm exhalations, but are all Entangled and enmassed, whereby at once Each is restrained by each, and from without Checked, till compelled more slowly to advance. But the primordial atoms with their old Simple solidity, when forth they travel Along the empty void, all undelayed By aught outside them there, and they, each one Being one unit from nature of its parts, Are borne to that one place on which they strive Still to lay hold, must then, beyond a doubt, Outstrip in speed, and be more swiftly borne Than light of sun, and over regions rush, Of space much vaster, in the self-same time The sun's effulgence widens round the sky. Nor to pursue the atoms one by one, To see the law whereby each thing goes on. But some men, ignorant of matter, think, Opposing this, that not without the gods, In such adjustment to our human ways, Can nature change the seasons of the years, And bring to birth the grains and all of else To which divine Delight, the guide of life, Persuades mortality and leads it on, That, through her artful blandishments of love, It propagate the generations still, Lest humankind should perish. When they feign That gods have stablished all things but for man, They seem in all ways mightily to lapse From reason's truth: for ev'n if ne'er I knew What seeds primordial are, yet would I dare This to affirm, ev'n from deep judgment based Upon the ways and conduct of the skies— This to maintain by many a fact besides— That in no wise the nature of the world For us was builded by a power divine— So great the faults it stands encumbered with: The which, my Memmius, later on, for thee We will clear up. Now as to what remains Concerning motions we'll unfold our thought. Now is the place, meseems, in these affairs To prove for thee this too: nothing corporeal Of its own force can e'er be upward borne, Or upward go—nor let the bodies of flames Deceive thee here: for they engendered are With urge to upwards, taking thus increase, Whereby grow upwards shining grains and trees, Though all the weight within them downward bears. Nor, when the fires will leap from under round The roofs of houses, and swift flame laps up Timber and beam, 'tis then to be supposed They act of own accord, no force beneath To urge them up. 'Tis thus that blood, discharged From out our bodies, spurts its jets aloft And spatters gore. And hast thou never marked With what a force the water will disgorge Timber and beam? The deeper, straight and down, We push them in, and, many though we be, The more we press with main and toil, the more The water vomits up and flings them back, That, more than half their length, they there emerge, Rebounding. Yet we never doubt, meseems, That all the weight within them downward bears Through empty void. Well, in like manner, flames Ought also to be able, when pressed out, Through winds of air to rise aloft, even though The weight within them strive to draw them down. Hast thou not seen, sweeping so far and high, The meteors, midnight flambeaus of the sky, How after them they draw long trails of flame Wherever Nature gives a thoroughfare? How stars and constellations drop to earth, Seest not? Nay, too, the sun from peak of heaven Sheds round to every quarter its large heat, And sows the new-ploughed intervales with light: Thus also sun's heat downward tends to earth. Athwart the rain thou seest the lightning fly; Now here, now there, bursting from out the clouds, The fires dash zig-zag—and that flaming power Falls likewise down to earth. In these affairs We wish thee also well aware of this: The atoms, as their own weight bears them down Plumb through the void, at scarce determined times, In scarce determined places, from their course Decline a little—call it, so to speak, Mere changed trend. For were it not their wont Thuswise to swerve, down would they fall, each one, Like drops of rain, through the unbottomed void; And then collisions ne'er could be nor blows Among the primal elements; and thus Nature would never have created aught. But, if perchance be any that believe The heavier bodies, as more swiftly borne Plumb down the void, are able from above To strike the lighter, thus engendering blows Able to cause those procreant motions, far From highways of true reason they retire. For whatsoever through the waters fall, Or through thin air, must quicken their descent, Each after its weight—on this account, because Both bulk of water and the subtle air By no means can retard each thing alike, But give more quick before the heavier weight; But contrariwise the empty void cannot, On any side, at any time, to aught Oppose resistance, but will ever yield, True to its bent of nature. Wherefore all, With equal speed, though equal not in weight, Must rush, borne downward through the still inane. Thus ne'er at all have heavier from above Been swift to strike the lighter, gendering strokes Which cause those divers motions, by whose means Nature transacts her work. And so I say, The atoms must a little swerve at times— But only the least, lest we should seem to feign Motions oblique, and fact refute us there. For this we see forthwith is manifest: Whatever the weight, it can't obliquely go, Down on its headlong journey from above, At least so far as thou canst mark; but who Is there can mark by sense that naught can swerve At all aside from off its road's straight line? Again, if ev'r all motions are co-linked, And from the old ever arise the new In fixed order, and primordial seeds Produce not by their swerving some new start Of motion to sunder the covenants of fate, That cause succeed not cause from everlasting, Whence this free will for creatures o'er the lands, Whence is it wrested from the fates,—this will Whereby we step right forward where desire Leads each man on, whereby the same we swerve In motions, not as at some fixed time, Nor at some fixed line of space, but where The mind itself has urged? For out of doubt In these affairs 'tis each man's will itself That gives the start, and hence throughout our limbs Incipient motions are diffused. Again, Dost thou not see, when, at a point of time, The bars are opened, how the eager strength Of horses cannot forward break as soon As pants their mind to do? For it behooves That all the stock of matter, through the frame, Be roused, in order that, through every joint, Aroused, it press and follow mind's desire; So thus thou seest initial motion's gendered From out the heart, aye, verily, proceeds First from the spirit's will, whence at the last 'Tis given forth through joints and body entire. Quite otherwise it is, when forth we move, Impelled by a blow of another's mighty powers And mighty urge; for then 'tis clear enough All matter of our total body goes, Hurried along, against our own desire— Until the will has pulled upon the reins And checked it back, throughout our members all; At whose arbitrament indeed sometimes The stock of matter's forced to change its path, Throughout our members and throughout our joints, And, after being forward cast, to be Reined up, whereat it settles back again. So seest thou not, how, though external force Drive men before, and often make them move, Onward against desire, and headlong snatched, Yet is there something in these breasts of ours Strong to combat, strong to withstand the same?— Wherefore no less within the primal seeds Thou must admit, besides all blows and weight, Some other cause of motion, whence derives This power in us inborn, of some free act.— Since naught from nothing can become, we see. For weight prevents all things should come to pass Through blows, as 'twere, by some external force; But that man's mind itself in all it does Hath not a fixed necessity within, Nor is not, like a conquered thing, compelled To bear and suffer,—this state comes to man From that slight swervement of the elements In no fixed line of space, in no fixed time. Nor ever was the stock of stuff more crammed, Nor ever, again, sundered by bigger gaps: For naught gives increase and naught takes away; On which account, just as they move to-day, The elemental bodies moved of old And shall the same hereafter evermore. And what was wont to be begot of old Shall be begotten under selfsame terms And grow and thrive in power, so far as given To each by Nature's changeless, old decrees. The sum of things there is no power can change, For naught exists outside, to which can flee Out of the world matter of any kind, Nor forth from which a fresh supply can spring, Break in upon the founded world, and change Whole nature of things, and turn their motions about.