On the Nature of Things (De Rerum Natura)
by Titus Lucretius Carus (c. 99 - c. 55 BCE)

This abridged presentation of Lucretius' famous six-book poem on nature focuses mostly on those passages essential to Epicureanism based on translations by Sisson and Rouse. The contents of these files are not public domain, but appear by permission of the copyright holders mentioned in the notices at the bottom of each page -- all rights reserved.  About 50% to 60% of the text from each book is represented here; breaks in the text are demarcated by a numeric heading which corresponds to the line number of the Latin manuscript.

An unabridged public-domain translation is also available at MIT.

Book IV


I wander over so many trackless places

no poet has been in before: I approach new springs

and drink them up: and I like to pick new flowers

to make an unusual wreath about my head:

First, because my subject is important,

nothing less than an attempt to get rid of religion;

Then because I make the most lucid verses

from obscure material and give it the grace of poetry.

There is, I may say, an excellent reason for that.

When doctors are giving children a bitter medicine

they first of all will smear the rim of the cup with honey

and in that way the sweet and golden liquid

deceives the children at least as far as their lips

and so they swallow down the bitter substance;

You may say they are beguiled but not betrayed

since by these means they recover health and strength:

So I now, since this doctrine is rather repugnant

to those not exercised in it, and for most people

something they would not touch, I wanted to put it

with all the agreeableness there can be in verse

and as it were smear it with poetical honey

to see if I could keep your mind on my verses

until you understood the order of nature

and felt the usefulness of what I am saying.


I have already explained the nature of mind,

its composition and how it works in the body

and how when detached it returns to its first elements.

Now I will start on another subject, closely

connected with it: the existence of images

which are like membranes from the surface of things;

once torn off they flutter here and there in the air,

and it is they which alarm us when they encounter our waking

minds, as they do in dreams, when we often see strange shapes

and the images of those who have lost the light

rouse us in horror as we lie powerless in sleep.

We should not think they are souls escaped from Acheron

or ghosts which are wandering around among living men,

nor that any part of us can be left after death

when the body and mind have been destroyed together

and both resolved once more into their elements.


What I am saying is that representations, filmy shapes

are sent off all the time from the surface of things

—something like membranes or you might call it a rind

since it has the appearance and form of the thing itself—

these things wander away from the body they come from.


I think I can demonstrate this even to the stupidest:

First, because it can be directly observed in many cases.

There are things that give off emanations which spread,

as smoke from burning wood or heat from fire;

There are others where what is given off is denser,

as the casings the cicadas shed in summer

and the membranes calves drop from around their bodies

when they are born; or the skin which slippery snakes

leave hooked on thorns, so that we often see

briars hung about with these fluttering trophies.

As these things happen, it must be that a thin image

is given off from the surface of things.

For why these things should fall in the way they do

but not the really thin films, is not demonstrable:

Especially since there are on the surface of bodies

many small particles, which could remain in the order

they were in before, and entirely keep their shape,

and come off more quickly since there is little to stop them

as they are, so to speak, in the very first line of particles.


We certainly see a number of things given off

not only from within, as I said before,

but from the surface of things, as happens with color:

You see how yellow and red and steely blue awnings,

stretched over theaters and billowing over the beams,

dye all the auditorium and those in it,

the scene itself, the senators, matrons, the gods,

making them all so to speak swim in the color;

And indeed the more they are shut in by high walls,

the more everything is gay in the rarefied light.

As the canvas gives the coloring off from its surface

so everything must give off a then film of likeness,

the surface in every case producing a discharge

and there are always shreds of appearances

fluttering about in the air, in a form so impalpable

that they cannot be distinguished in the ordinary way.



From some things there is a constant flow of smells,

coolness from rivers, heat from the sun, and from the sea, spray

which eats into walls placed on the seashore,

and a mixture of sounds is always in the air;

A wet salt taste comes often on our lips

when we walk by the sea; and if we watch

wormwood being prepared, the bitterness works on us.

So true is it that something is given off from everything

and ceaselessly carried away in all directions:

There is never any pause for these emanations;

We feel them all the time and we are forever

seeing or smelling, feeling or hearing something.


And since an object we handle in the dark

is known to be the same as the object we see

in the brightest light of day, it must be the case

that one and the same cause produces touch and sight.

For example, if we feel something square in the dark

what can it be which falls to our view in the light

except an image of that same square thing?

Images must therefore be what cause us to see

and it is clear that nothing can be seen without them.


These images I am talking about are carried

in all directions, they are projected everywhere:

It is true that because we see only with our eyes

it is only in the direction we turn out looks to

that things will strike us with their form and color.

It is also the image which makes it possible

for us to see how far away anything is.

When it leaves an object, it pushes before it

the air which is between the object and our eyes;

It flows across the surface of our eyes,

so to speak, brushing the pupils and passes on.

It is in that way that we are enabled to see

how far away anything is; the more air is pushed our way

and the longer the column of air which brushes our eyes,

the further away will the object seem to be.

Admittedly all this happens at high velocity,

so that when we see something, we see how distant it is.


It is not an objection to this theory

that the images which strike upon our eyes

cannot be separately seen, though the objects are seen.

It is as when a wind blows hard against us

or sharp cold flows about us, we do not feel

each individual particle of wind or of cold

but rather the general effect: we have the sensation

of a succession of blows upon our body

as if they were inflicted by a body outside it.

So when we tap a stone with our fingers, we touch

the outside of the rock, its surface and color;

But that is not what touch conveys to us, rather

we feel hardness running deep into the rock.



When we see far off the square towers of a town,

it often happens that they appear to us round;

any angle seen from far away looks obtuse

or not like an angle at all: the impact it gives

dies on the way and nothing of it reaches our eyes,

the images coming to us through so much air

are beaten about by the air and become less sharp.

When all the angles have thus eluded perception

it is as if the tower had been turned on a wheel,

not like something at hand which is really round

but rather with the outline sketched in a shadowy way.


Our shadow seems also to move in the sunshine,

to follow our footsteps and imitate our gestures;

(do you think that air which is deprived of light

can step out and follow the movements and actions of men?

For it can be nothing more than air without light,

that which we are accustomed to call our shadow.)

Particular bits of the ground are deprived of light

successively, as we move around in the world

and the area we leave is correspondingly filled;

that explains why the shadow cast by our body

appears to follow us from place to place.

All the time there are new rays pouring in

and the old disappear, like wool spun into the fire.

In the same way the whole earth is drained of light

and filled again and so washes away its shadows.

It is not a question of our eyes being deceived.

Their function is to observe where the light falls

and where there is shadow: but whether all lights are the same

and whether it is the same shadow, now here, now there

or whether things are not rather as we have explained them—

that is a matter for the mind to determine.

It is not for the eyes to find out the working of nature;

Don’t blame them for what the mind ought to be doing.



There are many other phenomena of this kind

which threaten the credibility of our senses:

Or seem to, for in fact they are for the most part

due to the judgment which we have added ourselves

so that we seem to see what in fact we do not see.

Nothing is harder than to distinguish between

patent facts and the doubts which the mind contributes.


Furthermore, anyone who thinks that nothing is known,

on his own admission he cannot assert even that.

I do not think it worth arguing a case

against a man who is standing on his head.

But let us suppose he does know nothing is known;

I would ask him, since he has seen no truth in anything,

how he can know what knowing and not knowing are?

What are the marks of truth and the marks of falsehood?

How can one tell the doubtful from the certain?

You will find that it is the senses which first created

the criterion of truth, they cannot be shown to be wrong:

Credibility must attach to whatever

makes it possible to set aside the false for the true.

What has more credibility than the senses?

Is it possible that a reason based on lying senses

should contradict them, since it is them she comes from?

If they are not true, then reason itself is a lie.

Can the ears correct the eyes? Or the touch the ears?

Can the sense of taste question the sense of touch?

Can the nose refute it? Or the eyes say it is false?

I do not think so: every sense has its function;

Each can do something the others cannot do.

One perceives hardness or softness, cold or heat;

Another perceives the variety of colors

and the qualities which go together with color.

Taste has its particular sense; smell has another,

and it is the same with sound; and so it must be

that no one sense can ever convince another,

nor can a particular sense correct itself

since it is as credible at one time as another.

What any sense perceives anywhere is true.


If reason cannot, for example, find out the cause

why an object which, close at hand, appears to be square,

looks round at a distance, it is very much better

to try to explain it by a false hypothesis

than to deny the manifest facts of the case,

to go against evidence and so tear up the foundations

on which our life and our safety must depend.

Not only would reason go down in the ruin;

Life itself would fall if you dared not trust the senses

to keep you away from precipices and such dangers

and to show you the sort of things that you can rely on;

So all that talk is absolutely vain

which seeks to ruin the credit of the senses.


In any building, if the basic measure is wrong

and there is error in judging the perpendicular

or the level somewhere is even the slightest bit wrong,

everything will be out of true and lopsided,

crooked, sloping, leaning this way or that;

It will threaten to fall and some of it actually will fall

and all on account of the first erroneous measurements:

So your reasoning about things is always bound to be false

if it is based on senses you cannot rely on.


The way in which the senses perceive their own objects

must now be explained; it is not a difficult matter.



The tongue and palate by which we can perceive flavors

may be explained without any greater difficulty.

First flavors are perceived in the mouth, when we masticate

what we eat, pressing it like a spongeful of water

when someone starts to squeeze it in his hand,

then what we press out goes through the pores of the palate

and finds its way through the intricacies of the tongue.

When the elements of the trickling flavor are smooth

the contact is pleasant and there is a pleasant tickling

around the moistening areas of the mouth.

But the elements bite and tear the organs of sense

more as they have more of roughness in them.


The pleasure of tasting things ends at the palate:

When once whatever provokes it has gone down the throat,

there is no pleasure, it simply spreads around the body:

It does not matter then what you have been fed on

so long as you can digest whatever it is

and it serves to keep the stomach moist as it should be.



Now let us talk about things which move the mind

and where they come from, I can explain it all.

First let me say, that there are many images

wandering around, you might say, all over the place.

They are tenuous and readily joined together in the air

when they meet, like spiders’ webs or gold leaf.

These things are of a far thinner texture

than those which strike the eye and give rise to vision;

They come in through the porous parts of the body,

touch the fine nature of the mind and make an impression.

That is how we come to see centaurs and bits of Scylla,

dogs which look like Cerberus, and the images

of those whose bones have long been underground.

All kinds of images are floating everywhere,

some of them generated in the air itself,

some having peeled off from the outside of things

and some made of a combination of both.

The centaurs’ images cannot come from the life

since there was never any such creature in nature.

When images of a horse and a man come together

they stick to one another, as I have shown.

An image of that kind makes an immediate impression

upon our minds, which are themselves of material

extremely tenuous and marvelous in its mobility.


This will show that my explanation is the correct one:

so far as what we see with the mind and the eyes

is similar, it must have a similar origin.

I have shown that the reason I see, for example, a lion

is that there are images which affect the eyes.

The mind must surely be moved in a similar way

by the image of the lion or of anything else,

just like the eyes, though it sees more tenuous images.

It is for this reason that when we are deep in sleep

but the mind is awake, we are trouble by those images

which stimulate our minds when we are awake

—to the point indeed that we seem to see

those whom death has taken and earth now holds.

Nature does things in this way because the senses

with the rest of the body are put out of action

and so cannot check the false against the true;

And because the memory is also asleep

and does not remind us that the person we think we see

has long been taken into the power of death.

No need to be surprised that the images move

their arms and legs in time, as sometimes

seems to happen with images seen in dreams.

For, as one image dies, another is born,

in another position, and so we think there is movement;

Of course all this happens at incredible speed.


One could ask many questions about all this.

There is much to explain if the matter is to be made clear.

In the first place, one might ask why as soon as we want to

think of anything the mind obliges and thinks of it.

Can it be that the images see what we are after

and, as soon, as we want it, a particular image pops up?

If we are preoccupied by sea, earth or sky,

assemblies, processions, banquets or maybe battles,

does nature produce them at the appropriate word?

The remarkable thing is that people in one spot

may none the less be thinking of different things.


What about when in dreams we see images

advancing in step and making flexible gestures,

swinging their arms in turn and with rapidity

and going over the movement again and again?

A skillful set of images, you might say;

Perhaps they took lessons in order to entertain us?

Will not the truth be, that the instant we are aware of,

in which the voice can utter a single word,

conceals other instants distinguishable by reason

and in any particular instant a number of images

is ready at hand on the spot in case they are wanted?

So mobile are they, and so great is the stock of them.

And since they are tenuous, unless it tries to, the mind

cannot see what is there; and the rest, which are not wanted,

are lost, leaving only those which the mind has need of.

It prepares for what is coming, and hopes it will see

what ought to follow: and that is just what it does see.


Do you not see that our eyes, when they are trying

to make out something fine, deliberately strain

and that without that we cannot see distinctly?

Even with things which are as plain as a pikestaff,

there has to be some attention or else they will seem

all the time to be a long way away.

What wonder then if the mind loses sight of everything

except the particular things it is attending to?

We are apt too, on the slightest indication,

to see great visions and so deceive ourselves.

It does not always happen that an image is followed

by another of the same kind, but what was a woman

turns out when we touch to be a man

or faces and ages change inconsequentially:

We are not astonished because of sleep and forgetfulness.


In matters of this kind there is a common fallacy

which you should run away from as if it would scorch you:

You should not imagine that eyes were made to see with

nor that the long steps we are able to take

explain the origin of the feet and legs

and why they are jointed in the way they are;

Nor that the arms are so fixed on the shoulders

and a pair of useful hands hung at our sides

to enable us to use them as we do.


Such explanations are based on erroneous reasoning.

Nothing of all the bits which make up our body

is there that we can use it; the use is invented

by the mere fact that the organ or limb is there:

There was no seeing until the eyes were born

nor was there speech before the tongue was created;

On the contrary, the tongue came a long time before speech;

The ears were invented before a sound was heard

and every organ, before it had any use.

So nothing came for the sake of the use we have found for it.


Yet obviously the habit of belligerence,

of breaking bones and spilling gallons of blood

had not to await the invention of arrows and javelins

and nature suggested the avoidance of wounds

before the left arm artfully held a shield;

The weary body would lay itself down to sleep

before soft beds were made for it to sleep on

and slaking thirst is older than drinking from cups.

Such articles, answering our daily needs,

may well be thought to have been designed for use.

It is otherwise with the things which were first created

and later gave us ideas of how we might use them.

Of these the limbs and senses are good examples.

It is quite impossible to believe that

they were created for us to use them as we do.


It is not to be wondered at that the body of every

living creature is such that it looks for food.

I have shown that particles flow away from everything

in various ways: and most of all they must flow

from living creatures, always in restless motion.

Many particles come from inside, carried out by sweat;

Many out of the mouth, when the creatures pant with fatigue.

In this way the body is rarefied, its very nature

undermined, and there is consequent pain.

Therefore food is taken to keep it together,

to give it strength by diffusion through the veins:

This has the effect of stopping the craving to eat.


Now how does it happen that we are able to walk

when we want to, and to make what movements we please?

And how do we manage to push our bodies about,

heavy as they are? I will tell you: and you pay attention.

An image of walking presents itself to the mind

and strikes it in the manner I have explained.

This gives the will: there cannot be any action

without the mind first determining what it wants,

which happens only when the image presents itself.

When the mind has bestirred itself and decides on walking

a step is made, for at once throughout the body

the soul is struck by elements of the mind,

which is easy enough, the two are so close together.

The soul then strikes on the body, and the whole bulk

is stimulated and so put in motion.

The body relaxes its tissues so that the air,

a substance which is eternally on the move,

comes into the openings, making its way through the pores

and spreads into the most minute parts of the body.

There are thus always these two causes in play

and the body moves like a ship with sails and wind.

There is, you will see, no occasion for astonishment

that such small elements can turn a body around

in spite of all its weight, for we know that the wind,

subtle and fine as it is, can drive on a ship

and a single hand steer however great the speed,

and a single rudder turn it wherever you like.

So it is with pulleys and that sort of equipment;

You have machines which can raise things with hardly an effort.



What powerful movements the human mind may have:

Often in sleep the same things harry us still.

Men throw down kings; themselves are taken in battle;

They raise a shout as if their throats were cut.

Many will struggle, emitting horrible groans

and just as if a panther or lion had bitten them

fill the place with the loudest possible cries.

Many will talk in sleep of important affairs;

It is not unknown for a man to speak of his crimes;

Many encounter death: and from high mountains

have the impression of falling to sea-level;

They are terrified, and when they awake their minds

are still so caught they hardly know what they are doing.

A man many feel thirsty and stop at the bank of a river

or at a spring and offer to drink the lot.

Children often, when they are fast asleep,

think they are on their pots or in the lavatory

and lift up their clothes and let out a whole bladderful,

making a mess on a fine Babylonian carpet.


The adolescent, boiling for the first time

with seed inside him, ripened that very day,

is met by images from some body or other

suggesting a lovely face and a beautiful color.

They rouse the parts which are swollen already with semen

until, as if the whole thing was really happening,

he pours out a river which spills all over his tunic.


The seed is excited in us as I have explained,

as soon as our first maturity gives us the strength.

Different things are excited by different causes;

It needs a human creature to call up the seed.

As soon as it has been elicited from its recesses,

it is drained away from every part of the body

and, collecting in the appropriate nerve centers,

it stirs up the genital organs without delay.

Provoked by the seed, these places swell; and the impulse

is to eject it towards the ominous object;

So the whole mind seeks the body with is causing the damage.

Men usually fall on the side on which they are wounded;

The blood flows in the direction the blow comes from,

and straight at the enemy if he stands in the way.


It is the same with a man wounded by Venus’ arrows,

whether they come at him from a girlish boy

or from a woman whose whole body hurls love at him;

He runs at the person who shot him and wants to copulate

and to plant in that body the fluid from his own body;

His dumb desire suggests it will give him pleasure.

That is Venus for you, it is that which we call love

which is the source of sweetness which Venus pours

drop by drop in our hearts: and then we are worried.

If what you want isn’t there, there are always images

of her, and her sweet name will ring in your ears.


Keep off imagination and frighten away

whatever encourages love; turn your mind elsewhere,

get rid of the fluid in any body you can

instead of keeping it for a single person

which is bound to lead to trouble and end in grief.

If you have an ulcer there is no point in feeding it,

the madness gets worse every day and the burden intolerable

if you do not confuse the first wound with several others

and wander and lose yourself in the genial Venus:

Unless you can turn your mind to another subject.


No need to do without sex if you keep off love;

You simply have it without the disadvantages.

For surely those who are perfectly well have more pleasure

than the afflicted: even in the moment of triumph

lovers drift in all kinds of doubts and confusions,

not knowing whether to start with the eye or the hands.

They squash the body they sought until it squeals

and often their teeth make a gash on the lips

in the course of affixing a kiss, which is hardly pure pleasure.

They are indeed rather provoked to injure the object,

whatever it is, which causes this onset of lunacy.

But Venus mitigates pains such as these for the lover

and a gentle admixture of pleasure will soften the bite.


For the hope is always that the body which causes this ardor

will prove the best instrument for quenching the flame,

which is quite contrary to the order of nature.

This is the one case in which the more we have

the more we burn with furious desire for more.

Food and drink are taken into the body,

they fill up certain spaces and that is that,

the craving for solitude and liquids is easily satisfied

but with human faces and beautiful complexions

there is nothing to take in and enjoy but a pack of images,

a wretched hope which the wind can blow away:

just as when a thirsty man tries to drink in a dream

He cannot get a drop which will really slake his limbs,

he goes after imaginary liquid and labors in vain

and is thirsty even while drinking a raging river.

So in love Venus plays with her lovers in images;

They cannot be satisfied by looking at bodies

nor can they scrape off bits of delicious limbs

But think they might and roam all over the body.


When with limbs together they enjoy the flower of their age

and the body has a premonition of pleasure,

with Venus ready to sow the feminine fields,

They catch at each other greedily, exchanging spittle,

and sigh in pressing each other’s mouth with their teeth.

It is no good; they cannot get anything off;

they cannot get into the body with the whole body.

They seem to want to, however, and make immense efforts

to the point that they stick in the embraces of Venus

until their limbs melt with the force of the pleasure.

When the desire in their sinews has made its eruption

there is a little pause in the violence of their ardor:

Then the lunacy breaks out again and the frenzy comes back

when they ask what it is they should like to obtain for themselves

and cannot find any device which will make them feel better,

so not knowing they pine away with a blind disease.


Besides, they use up their strength by overdoing it;

Not only that, they live at the whim of another.

Their money turns into Babylonian embroideries;

They neglect their business and their good name becomes shaky;

There are perfumes; her feet must be shod in beautiful slippers;

Enormous emeralds gleam on her, set in gold,

Yet the sea-colored gown will wear out quickly enough

with all the amorous sweat that it has to mop up.

The patrimony turns into ribbons and headgear,

dresses which come all the way from Alinda or Cos.

It all goes in dinners with clothes and expensive food,

shows, lots of drink, and bath-salts and head-bands and garlands.

Quite useless, for out of the source of so many attractions

something bitter comes up, and the flowers are a pain.

Either the mind will reflect and become remorseful

at so much waste of time in pursuit of debauchery

or else the girl lets drop some ambiguous expression

which sticks in the heart and burns away like a fire,

or possibly turns her eyes in the wrong direction

and lets fall the trace of a smile at somebody else.


These evils are found in the most prosperous love:

As to the ills of those who simply get nowhere

you can close your eyes and imagine how many they are:

They are innumerable—so better watch out

and take good care, as I said, that you don’t get caught.

To avoid falling into an amorous entanglement

is not so hard as to get out once you are in

for the knots Venus makes are very hard to untie.


But even if you are caught in the entanglement

you can avoid the worst if you don’t stand in your own way

by blinding yourself to the faults of mind and body

there are in the person you are so keen to follow.

Yet this is exactly what men generally do;

They attribute qualities which are simply not there.

We often see misshapen, disgusting women

regarded as charming, indeed, you might say worshipped.

Men will mutually give ironic advice

about horrible passions they notice in one another

without the least regard to their own misfortunes.

A dark girl looks like honey; an unwashed one is natural;

The cat-eyed bitch is a goddess; the stringy one is a sylph;

The undersized, under-grown one, a minute gem;

The overgrown monster has an extraordinary dignity;

The girl with a stammer has a bit of a lisp;

The dumb girl is just diffident; while the screaming,

big-mouthed harpy is bubbling over with life;

A girl is slim when she is at death’s door,

she is so thin; or sensitive, when she’s consumptive;

If she has a mountainous bosom she is jolly;

If her nose is flat she’s puckish; thick lips give a lovely kiss:

Really one can’t go on with the recitation.


Even supposing the girl you love is beautiful

and her body has every kind of amorous attraction:

Still, there are others, and you did without her before;

And she does all the things the most unpleasant ones do

and chokes herself with the horrible smells she gives off

while her maids run away or snigger behind her back.


The tearful lover, shut out, will cover the entrance

with flowers and even garlands, while the splendid doorposts

he plasters with oil of marjoram, adding his kisses.

Yet, if he were let in, one whiff from the boudoir

would make him think of excuses for getting away;

His long-thought-out campaign would be forgotten;

He would curse the stupidity which made him think of her

as somebody who wasn’t actually mortal.

Our Venuses know all this and go to great pains

to keep such matters hidden behind the scenes:

It is hardly worth it; a little reflection will tell us

just what is happening and why the servants are giggling.

If the girl is sensible and not full of pretenses,

be sensible too and allow her human functions.



Yet sometimes without the intervention of Venus,

a rather sub-average woman may come to be loved.

She manages by herself and by what she does,

by compliant ways and keeping her body clean

to get a man used to sharing her existence.

For the rest, what you get used to you tend to love;

However light the blows, if they are repeated

they will end by bringing down whatever it is.

It has long been a matter of ordinary observation

that constant dripping wears away the stone.