On the Nature of the Universe (Oxford World’s Classics) Read online

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  Provided good digestion waits on it

  Letting its virtue spread through all the limbs

  And keep intact the moisture of the stomach.

  Now I shall explain why different food

  Is sweet and nourishing for different creatures,

  And why what is to some unpleasant and bitter

  Can yet to others seem truly delicious,

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  Why in these things there is such great difference

  That one man’s meat is another’s deadly poison.

  It is like the snake, which touched by human spittle,

  Bites itself to death, and perishes.

  And hellebore to us is deadly poison

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  But fed to goats and quails it makes them fat.

  Now, that you may understand why these things happen

  You must first remember what I said before

  That things contain seeds mixed in many ways.

  In fact all living creatures that take food

  As they are different externally

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  And the contour and circumscription of their limbs

  Compass each according to its kind,

  So they are made of seeds of different shape;

  And since the seeds differ, so also must

  The intervals and paths, which we call channels,

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  Differ throughout our body, and in our mouth and palate.

  Some therefore must be larger and some smaller,

  And some triangular and others square,

  And many round, and some with many angles,

  Disposed in many different arrangements.

  For as the order and motions of figures require

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  The channels of the figures must be different

  And the paths vary as the texture compels.

  Therefore if what is sweet to some is bitter to others,

  When it is sweet to one, very small bodies

  Must enter the pores of the palate with soothing touch.

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  But if it tastes bitter, that is no doubt because

  Rough and hooked atoms penetrate the throat.

  Thus it is easy to understand each case.

  For when fever grips a man through excess of bile

  Or disease is excited in some other way,

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  Then the whole body is thrown into confusion

  And all the positions of its atoms are upset,

  So that all the bodies which conformed with the senses

  Conform no longer, and others come more apt

  To penetrate and produce a bitter taste.

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  Indeed in honey both these tastes are mixed,

  A thing which I have explained to you before.

  I now examine how the impact of smell

  Affects the nose. First of necessity

  There must be many things from all of which

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  Flows rolling out a varied stream of odours

  Which flow and are sped and scattered everywhere.

  But different scents suit different animals

  Because of their different shapes. Bees are attracted

  Over great distances by the smell of honey,

  Vultures by carcasses. A pack of hounds

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  Leads where the cloven hoof of game has gone.

  And from afar the scent of man is caught

  By the white goose that saved Rome’s citadel.

  So different scent is given to different creatures

  And leads each to its food, and forces it

  To leap back from loathsome poison; and in this way

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  The generations of wild beasts are preserved.

  Take all the smells then that assail the nostrils:

  One may be carried farther than another

  But yet no smell can ever travel as far

  As sound or voice or (and I need not add)

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  Those things which strike the eye and give us sight.

  It wanders slowly coming and dies first

  Gradually dispersed into the winds of air.

  There are two reasons for this; first because

  It comes with difficulty from the depths of things:

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  Things have a stronger smell when broken up,

  Or crushed, or melted down by fire; this means

  That scent flows out released from deep within.

  Second, it may be seen that smell is made

  Of larger elements than voice, since through stone walls

  It cannot pass as voice and sounds may do.

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  Wherefore also you will see that it is not so easy

  To trace out where scent is coming from,

  For the flow grows cold as it dawdles through the air

  And no messenger runs hot-foot to the sense.

  This is why in the chase we often see

  Hounds are at fault and cast about for scent.

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  Nor yet is this confined to smells and tastes:

  The look of things also and their various colours

  Do not all suit the senses in the same way

  But to some they come much sharper than to others.

  The cock, that claps the night out with his wings

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  And with clear voice is wont to call the dawn,

  Before him ravening lions cannot stand

  Or stare, so instantly flight fills their minds,

  Doubtless since in the cock’s body certain seeds

  There are which when sent into the lion’s eyes

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  Dig holes in the pupils and cause stinging pain

  Which fierce though they may be they cannot endure.

  And yet these cannot hurt our sight at all,

  Either because they do not penetrate

  Or if they do they find a ready exit

  From the eyes and so do not by lingering

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  Damage the light of the eyes in any part.

  Now I shall tell you what things move the mind,

  And whence those things which come into the mind

  Do come, in a few words I shall explain.

  First I say this, that images of things

  Many in many modes wander about

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  In all directions, thin, and easily

  Unite when they meet in the air, like spiders’ webs

  Or leaf of gold, of texture much more thin

  Than those which strike the eyes and provoke vision.

  For they penetrate the chinks of the body, and stir

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  The thin substance of the mind and provoke sensation.

  Centaurs and mermaids in this way we see

  And dogs with many heads like Cerberus,

  And images of men when after death

  Their bones lie in the cold embrace of earth.

  For images of every kind fly everywhere;

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  Some of their own accord form in the air,

  Some are thrown off from many different things,

  Others combine together from these shapes.

  For sure no image of a Centaur came from life

  Since no such animal did ever exist.

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  But when the images of man and horse

  Happen to meet, they easily adhere

  Immediately, as I said before,

  Because of their subtle nature and thin texture.

  All things of this kind are made in this way.

  And since being very light they are so mobile,

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  As I showed before, any one of these fine images

  By a single touch can easily move the mind,

  For the mind is thin and marvellously mobile.

  That these things happen as I say, you may know

  Quite easily from what I now sha
ll tell you.

  Since this is like that—what in the mind we see

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  Like what we see with our eyes—it needs must be

  That both are caused by similar processes.

  Now therefore since I have shown that I see a lion

  By means of images which strike the eyes,

  It is clear that in like way the mind is moved.

  It sees the lion and everything else by images

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  No less than the eyes, though what it sees is thinner.

  Nor is there any other reason why,

  When sleep has laid out the limbs, the mind is awake,

  Than this, that these same images assail

  The mind as when we are awake. Indeed

  We seem to see a man who has left this life

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  And death and earth have mastered him. So great

  Is the power of nature. All our senses

  Lie quiet throughout the body and are blocked,

  Unable to refute the false by the true.

  And memory faints in sleep, and languishes,

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  And when the mind thinks it sees the man alive

  It does not dissent, and say that long ago

  The man was dead and in death’s mighty power.

  And it is not wonderful that images move

  And sway their arms and other limbs in rhythm—

  For the image does seem to do this in our sleep.

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  The fact is that when the first one perishes

  And a new one is born and takes its place,

  The former seems to have changed its attitude.

  All this of course takes place extremely swiftly,

  So great is the velocity and so great the store

  Of them, so great the quantity of atoms

  In any single moment of sensation

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  Always available to keep up the supply.

  And many are the questions to be asked

  About these things, and many explanations given

  If we desire to make the matter clear.

  The first question is, why is it that the mind,

  As soon as it fancies something, thinks of it?

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  Is there an image that waits upon our will

  And as soon as we wish presents itself to us,

  Of sea or land, as we may choose, or sky?

  Assemblies of men, processions, banquets, battles,

  Does nature create them at a word and prepare them for us?

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  And all the while, at the same place and time,

  Other minds are thinking of quite different things.

  And what when we see in dreams the images

  Moving in time and swaying supple limbs,

  Swinging one supple arm after the other

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  In fluid gestures and repeating the movement

  Foot meeting foot, as eyes direct? Ah, steeped in art,

  Well trained the wandering images must be

  That in the night have learned such games to play!

  Or will this rather be the reason? that

  In one instant of time that we perceive and one voice

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  Is uttered, many units of time are there

  All unperceived, though reason knows of them,

  And at any moment all these images

  Are present ready to hand in every place.

  And because they are thin the mind cannot clearly see

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  Any except those which it strains to perceive;

  The rest all perish, and only those survive

  Such as it has prepared itself to see:

  And it does prepare itself, and hopes to see

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  What follows on each thing; and it does see it.

  Do you not know that when even our eyes begin

  To look at thin things they strain and prepare themselves

  And otherwise we could not clearly see them.

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  And even in things plainly visible

  You will find that unless you apply your mind to them

  They might just as well be far removed from you.

  What wonder is it then, if the mind misses

  Everything except what it is itself intent on?

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  So from small signs we draw great inferences

  And lead ourselves into error and delusion.

  It sometimes happens also that the image

  Which follows is of a different kind: a woman

  Seems in our grasp to have become a man.

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  And different shapes and different ages follow.

  But sleep and oblivion cause us not to wonder.

  Now here’s a fault you must most keenly avoid,

  An error from which with great care you must flee:

  Do not suppose that the clear light of the eyes

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  Was made that we might see our way before us,

  Or that the ends of thighs and calves were jointed

  And set on the foundation of the feet

  To help us with great strides to march along,

  Or that our arms were fitted to stout shoulders

  With ministering hands on either side

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  To enable us to do what life requires.

  Every interpretation of this kind

  Is quite perverse, turns reason upside down,

  Since nothing is born in our body that we may use it,

  But what is born itself creates the use.

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  There was no sight before the eyes were born

  Or speech of words before the tongue was made,

  But long before speech is the tongue’s origin,

  Long before sound was heard our ears were made,

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  And all our limbs existed, as I think,

  Before their use. It cannot therefore be

  That they could have grown for the sake of being used.

  No. But fighting hand to hand in battle,

  Tearing of limbs and fouling bodies with blood

  Came long before bright shafts of weapons flew;

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  And nature taught men to avoid a wound

  Before through art the left arm opposed a shield.

  And sure to give the wearied body rest

  Is much more ancient than soft mattresses.

  Men quenched their thirst long before cups were made.

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  These things which men found out from life and need

  Were doubtless fashioned for the sake of use.

  Quite different are those things which came into being

  Before any conception of their usefulness;

  And first in this class are the senses and the limbs.

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  Wherefore again and yet again I say

  Banish from your mind the possibility

  That they could have been made for the sake of usefulness.

  Nor is there any reason to be surprised

  That by the very nature of its body

  Every animal seeks food. I have shown you that

  Many atoms in many ways are thrown off from things,

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  But most must come from animals. Always these are

  In motion, and many atoms are pressed out

  From deep down in sweat and many through the mouth

  As they pant in exhaustion, so the body is rarefied

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  And its nature undermined; and pain results.

  So food is taken, to prop up the body,

  And working inside renews the strength and stops

  Through veins and limbs the gaping desire to eat.

  And fluid also goes into all those parts

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  That need it, and the massed particles of heat

  That set our stomach in a blaze are scattered

 
By the fluid entering, and quenched like fire,

  So the parching heat no longer burns our frame.

  Thus then your panting thirst is swilled away

  Out of the body, thus your famished craving

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  Is satisfied, the body’s needs fulfilled.

  Now I will tell you how it is that we walk

  And can stride forward when we wish, and how

  We are able to move our limbs in various ways,

  And what it is that is wont to push along

  Our body’s heavy weight. Please mark my words.

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  I say that in the first place images

  Of walking come in contact with the mind

  And strike the mind, as I have said before.

  Hence follows will: for no one ever begins

  Anything unless the mind has first foreseen

  What it wills to do (and what the mind foresees

  Is the image of the thing). Therefore the mind

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  When it conceives the wish of walking forward

  Immediately strikes the mass of spirit

  Dispersed through all the body and the limbs

  (And this is easy for it, since it lives

  In such close combination with the spirit).

  The spirit then strikes the body, and so the whole mass

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  Is gradually pushed forward into movement.

  The body then also expands its pores, and air,

  As is natural with something always mobile,

  Pours into the opened passages and penetrates them,

  Thus reaching the very smallest parts of the body.

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  So thus by two things acting in two ways

  The body is moved, like a ship by sails and wind.

  Nor is there anything surprising here

  That elements so small can turn so large

  A body and twist our whole weight around.

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  The wind, that is so subtle and so fine,

  Drives on a mighty ship with mighty power,

  And one hand rules it whatever its speed may be,

  One rudder steers it whither you may will;

  And many a heavy weight by blocks and pulleys

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  A derrick can move and lift with little effort.

  Next, in what way sleep floods the limbs with peace

  And from the heart lets free the mind’s disquiet

  I shall declare in verses sweet though few.

  Better the swan’s brief song than that cry of cranes

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  Spread by the south wind through the clouds on high.

  Give me keen ears and understanding mind

  Lest you deny that what I say can be,

  And shrink back, your heart repelling words of truth

  Though you are in fault yourself and cannot see it.

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  In the first place, sleep comes when the power of the spirit

  Is drawn apart through the body, and part of it

  Cast forth has gone away, and part retreats