On the Nature of Things · 6 of 30

Book II, Part 2

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 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?

Insight

Here is the clinamen — the famous swerve. If atoms are merely falling parallel through void, like rain, they will never collide, never combine, and no world will ever form. So Lucretius posits that they swerve, very slightly, unpredictably, at no fixed time and at no fixed place. It is the most-discussed concept in the poem. The amount of swerve is minimal — Lucretius is careful not to make atoms sashay around — but the existence of even a tiny indeterminacy in their fall is the whole point. Without it, the universe is a closed deterministic chain; with it, the chain has a crack in it. From this crack, in the next paragraph, Lucretius will derive human freedom.Lucretius II.216-293 on the clinamen; Cicero De Fato 22 records the doctrine; modern reception in Bergson, Marx's doctoral dissertation, Deleuze.

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. ATOMIC FORMS AND THEIR COMBINATIONS Now come, and next hereafter apprehend What sorts, how vastly different in form, How varied in multitudinous shapes they are- These old beginnings of the universe; Not in the sense that only few are furnished With one like form, but rather not at all In general have they likeness each with each, No marvel: since the stock of them's so great That there's no end (as I have taught) nor sum, They must indeed not one and all be marked By equal outline and by shape the same.

Insight

The argument from free will. If everything that happens follows necessarily from prior causes, where does free will come from? It must come from somewhere, because we feel ourselves to be agents — when desire moves us, we step forward; when something stops us, we resist. So somewhere in the causal chain there has to be a small unmotivated origin of motion. The clinamen is what does that work. The argument is closer to Augustine and Pelagius wrestling over the will than to anything in modern compatibilism. It is also imperfectly worked out: critics from Cicero on have asked how a random swerve in atoms gives rise to a meaningful choice, and the question has never been fully answered. But Lucretius's instinct — that the doctrine of total causal closure leaves no room for the agency we actually experience — is one that every later philosopher of freedom has had to reckon with.Lucretius II.251-293; Cicero, De Fato 23-25 critiquing the swerve; Augustine, On Free Choice of the Will.

Moreover, humankind, and the mute flocks Of scaly creatures swimming in the streams, And joyous herds around, and all the wild, And all the breeds of birds- both those that teem In gladsome regions of the water-haunts, About the river-banks and springs and pools, And those that throng, flitting from tree to tree, Through trackless woods- Go, take which one thou wilt, In any kind: thou wilt discover still Each from the other still unlike in shape. Nor in no other wise could offspring know Mother, nor mother offspring- which we see They yet can do, distinguished one from other, No less than human beings, by clear signs. Thus oft before fair temples of the gods, Beside the incense-burning altars slain, Drops down the yearling calf, from out its breast Breathing warm streams of blood; the orphaned mother, Ranging meanwhile green woodland pastures round, Knows well the footprints, pressed by cloven hoofs, With eyes regarding every spot about, For sight somewhere of youngling gone from her; And, stopping short, filleth the leafy lanes With her complaints; and oft she seeks again Within the stall, pierced by her yearning still. Nor tender willows, nor dew-quickened grass, Nor the loved streams that glide along low banks, Can lure her mind and turn the sudden pain; Nor other shapes of calves that graze thereby Distract her mind or lighten pain the least- So keen her search for something known and hers. Moreover, tender kids with bleating throats Do know their horned dams, and butting lambs The flocks of sheep, and thus they patter on, Unfailingly each to its proper teat, As Nature intends. Lastly, with any grain, Thou'lt see that no one kernel in one kind Is so far like another, that there still Is not in shapes some difference running through. By a like law we see how earth is pied With shells and conchs, where, with soft waves, the sea Beats on the thirsty sands of curving shores. Wherefore again, again, since seeds of things Exist by nature, nor were wrought with hands After a fixed pattern of one other, They needs must flitter to and fro with shapes In types dissimilar to one another.

Easy enough by thought of mind to solve Why fires of lightning more can penetrate Than these of ours from pitch-pine born on earth. For thou canst say lightning's celestial fire, So subtle, is formed of figures finer far, And passes thus through holes which this our fire, Born from the wood, created from the pine, Cannot. Again, light passes through the horn On the lantern's side, while rain is dashed away. And why?- unless those bodies of light should be Finer than those of water's genial showers. We see how quickly through a colander The wines will flow; how, on the other hand, The sluggish olive-oil delays: no doubt, Because 'tis wrought of elements more large, Or else more crook'd and intertangled. Thus It comes that the primordials cannot be So suddenly sundered one from other, and seep, One through each several hole of anything.

And note, besides, that liquor of honey or milk Yields in the mouth agreeable taste to tongue, Whilst nauseous wormwood, pungent centaury, With their foul flavour set the lips awry; Thus simple 'tis to see that whatsoever Can touch the senses pleasingly are made Of smooth and rounded elements, whilst those Which seem the bitter and the sharp, are held Entwined by elements more crook'd, and so Are wont to tear their ways into our senses, And rend our body as they enter in. In short all good to sense, all bad to touch, Being up-built of figures so unlike, Are mutually at strife- lest thou suppose That the shrill rasping of a squeaking saw Consists of elements as smooth as song Which, waked by nimble fingers, on the strings The sweet musicians fashion; or suppose That same-shaped atoms through men's nostrils pierce When foul cadavers burn, as when the stage Is with Cilician saffron sprinkled fresh, And the altar near exhales Panchaean scent; Or hold as of like seed the goodly hues Of things which feast our eyes, as those which sting Against the smarting pupil and draw tears, Or show, with gruesome aspect, grim and vile. For never a shape which charms our sense was made Without some elemental smoothness; whilst Whate'er is harsh and irksome has been framed Still with some roughness in its elements. Some, too, there are which justly are supposed To be nor smooth nor altogether hooked, With bended barbs, but slightly angled-out, To tickle rather than to wound the sense- And of which sort is the salt tartar of wine And flavours of the gummed elecampane. Again, that glowing fire and icy rime Are fanged with teeth unlike whereby to sting Our body's sense, the touch of each gives proof. For touch- by sacred majesties of gods!- Touch is indeed the body's only sense- Be't that something in-from-outward works, Be't that something in the body born Wounds, or delighteth as it passes out Along the procreant paths of Aphrodite; Or be't the seeds by some collision whirl Disordered in the body and confound By tumult and confusion all the sense- As thou mayst find, if haply with the hand Thyself thou strike thy body's any part. On which account, the elemental forms Must differ widely, as enabled thus To cause diverse sensations. And, again, What seems to us the hardened and condensed Must be of atoms among themselves more hooked, Be held compacted deep within, as 'twere By branch-like atoms- of which sort the chief Are diamond stones, despisers of all blows, And stalwart flint and strength of solid iron, And brazen bars, which, budging hard in locks, Do grate and scream. But what are liquid, formed Of fluid body, they indeed must be Of elements more smooth and round- because Their globules severally will not cohere: To suck the poppy-seeds from palm of hand Is quite as easy as drinking water down, And they, once struck, roll like unto the same. But that thou seest among the things that flow Some bitter, as the brine of ocean is, Is not the least a marvel... For since 'tis fluid, smooth its atoms are And round, with painful rough ones mixed therein; Yet need not these be held together hooked: In fact, though rough, they're globular besides, Able at once to roll, and rasp the sense. And that the more thou mayst believe me here, That with smooth elements are mixed the rough (Whence Neptune's salt astringent body comes), There is a means to separate the twain, And thereupon dividedly to see How the sweet water, after filtering through So often underground, flows freshened forth Into some hollow; for it leaves above The primal germs of nauseating brine, Since cling the rough more readily in earth. Lastly, whatso thou markest to disperse Upon the instant- smoke, and cloud, and flame- Must not (even though not all of smooth and round) Be yet co-linked with atoms intertwined, That thus they can, without together cleaving, So pierce our body and so bore the rocks. Whatever we see... Given to senses, that thou must perceive They're not from linked but pointed elements.

The which now having taught, I will go on To bind thereto a fact to this allied And drawing from this its proof: these primal germs Vary, yet only with finite tale of shapes. For were these shapes quite infinite, some seeds Would have a body of infinite increase. For in one seed, in one small frame of any, The shapes can't vary from one another much. Assume, we'll say, that of three minim parts Consist the primal bodies, or add a few: When, now, by placing all these parts of one At top and bottom, changing lefts and rights, Thou hast with every kind of shift found out What the aspect of shape of its whole body Each new arrangement gives, for what remains, If thou percase wouldst vary its old shapes, New parts must then be added; 'twill follow next, If thou percase wouldst vary still its shapes, That by like logic each arrangement still Requires its increment of other parts. Ergo, an augmentation of its frame Follows upon each novelty of forms. Wherefore, it cannot be thou'lt undertake That seeds have infinite differences in form, Lest thus thou forcest some indeed to be Of an immeasurable immensity- Which I have taught above cannot be proved.