On the Nature of the Universe (Oxford World’s Classics) (16 page)

But let’s suppose another man has struck us

A violent blow—he’s hit us really hard—

And we move forward. That’s quite different.

For all the matter then of all the body

Clearly against our will is forced to move,

275

Until the will has reined limbs back again.

Do you see the point? Though many men are driven

By an external force, compelled to move

Often in headlong rush against their will,

Yet in our breasts there’s something that has the power

To fight against this force and to resist it.

280

At its command at times the mass of matter

Is forced to change direction in our limbs,

Or, reined back on its way, it comes to rest.

The same thing therefore we must admit in atoms:

That in addition to their weights and impacts

285

There is another separate cause of motion,

From which we get this innate power of ours,

Since nothing ever can be produced from nothing.

For it is weight that prevents all things being caused

Simply by external impacts of other atoms.

But that within the mind there’s no necessity

290

Controlling all its actions, all its movements,

Enslaving it and forcing it to suffer—

That the minute swerving of atoms causes

In neither place nor time determinate.

The mass of matter in the universe

Was never more tightly packed than it is now,

Nor ever set at wider intervals.

295

Nothing increases it or is taken away from it.

Therefore the motions in which the primal atoms

Are now have been the same for ages past,

And in like manner they will move hereafter.

And things which the ancient custom of the world

Has brought to birth will always in like manner

300

Be brought to birth, and be and grow and flourish,

So far as to each is given by Nature’s laws.

No power can ever change the sum of things.

No place exists to which any kind of matter

Could escape from the universe, nor any place

305

From out of which some new force building up

Could break into the universe, and change

The nature of all things, and reverse their movements.

And here’s a thing that need cause no surprise:

That though all atoms are in ceaseless motion

Their total seems to stand in total rest,

310

Except so far as individual objects

Make movements by the movements of their bodies.

For all the nature of the primal atoms

Lies hidden far beneath our senses; therefore since

You cannot see them, you cannot see their movements.

Indeed things we can see, if some great distance

315

Divides them from us, oft conceal their movements.

You see sheep on a hillside creeping forward

Cropping the fresh green grass new-pearled with dew

Where pastures new invite and tempt them on,

And fat lambs play and butt and frisk around.

320

We see all this confused and blurred by distance,

A white patch standing still amid the green.

And when in mimic war the mighty legions

Fill all the plain with movements far and wide,

And sheen of armour rises to the sky;

325

Earth flashes with bronze; the tramp of marching feet

Resounds on high; the hills struck by the noise

Throw back the echoes to the stars of heaven;

And wheeling horsemen gallop, and suddenly

Charge, and shake all the plain with their attack—

330

And yet among high mountains there’s a place

From which they seem to stand still, motionless,

A flash of brightness on the plain below.

Now let us consider the qualities of atoms,

The extent to which they differ in their shapes

And all the rich variety of their figures.

335

Not that there are not many of the same shape,

But all by no means are identical.

Nor is this strange. For since their multitude

As I have shown has neither sum nor end,

Not all, for sure, must be the same in build

340

As all the rest, nor marked by the same shape.

Consider the race of men, and silent shoals

Of scaly fish, fat cattle, and wild beasts,

And all the varied birds that throng the waters

By joyful lakes and streams and river banks,

345

And flock and fly among the pathless woods.

Take any one you will among its kind,

And you will find they all have different shapes.

This is the only way the young can know

Their mothers, and the mothers know their young.

350

And this we see they do; no less than men

They recognize each other readily.

For oft in front of noble shrines of gods

A calf falls slain beside the incensed altars,

A stream of hot blood gushing from its breast.

The mother wandering through the leafy glens

355

Bereaved seeks on the ground the cloven footprints.

With questing eyes she seeks if anywhere

Her lost child may be seen; she stands, and fills with moaning

The woodland glades; she comes back to the byre

Time and again in yearning for her calf.

360

Nor tender willows nor meadows lush with dew

Nor those sweet rivers brimming to their banks

Can charm her mind or ease the sudden care,

Nor sight of other calves in happy pastures

Divert her mind and lift the care away,

So does she seek what was her own, her darling,

365

So steadfastly the child she knows so well.

And tender kids with trembling voices know

Their horned mothers well, and playful lambs

The bleating ewes. So each as Nature bids

To its own udder scampers back for milk.

Lastly, consider corn of any kind.

370

Not every grain you’ll find is quite the same,

But through their shapes there runs some difference.

So likewise all the various shells we see

Painting the lap of earth, the curving shore

375

Where waves beat softly on the thirsty sands.

Therefore again and yet again I say

That in the same way it must be that atoms,

Since they exist by nature and are not made by hand

To the fixed pattern of a single atom,

Must, some of them, be different in their shapes.

380

With this in mind it is easy to explain

Why the fire of lightning penetrates much further

Than our fire does which springs from earthly torches.

For you could say that the heavenly fire of lightning

Is finer, being composed of smaller shapes

And therefore passes through apertures impassable

385

By our fire sprung from wood and lit by torch.

Besides, light passes through a pane of horn, but rain

Is thrown off. Why? Because the atoms of light

Are smaller than those that make life-giving water.

390

And though we see wine pass quickly through a strainer,

Yet olive oil by contrast lags and lingers;

No doubt, either because its atoms are larger

Or they are more hooked and more closely interwoven,

And therefore cannot separate so quickly

395

And trickle through the holes each one by one.

And here’s another thing. Honey and milk

Rolled in the mouth have a delightful taste;

But bitter wormwood and harsh centaury

400

Quite screw the face up with their loathsome flavour.

So you can easily see that smooth round atoms

Make up things which give pleasure to our senses,

But, by contrast, things that seem harsh and bitter

Are more composed of atoms that are hooked,

405

Which therefore tear their way into our senses,

And entering break the surface of our bodies.

There is conflict between those things that strike the senses

As good or bad, because their shapes are different.

The strident rasping of a screeching saw

You must not think consists of elements

As smooth as melodies musicians shape

Waking the tuneful lyre with nimble fingers.

Nor must you think that atoms of the same shape

Enter men’s nostrils when foul corpses burn

415