Principles of the Atomic Theory

Author: Lucretius

Principles of the Atomic Theory


Terror and darkness of the mind, therefore, it is not the rays of the sun, or the bright shafts of day, that must dispel, but reason and the contemplation of nature; of which our first principle shall hence take its commencement, THAT NOTHING IS EVER DIVINELY GENERATED FROM NOTHING. For thus it is that fear restrains all men, because they observe many things effected on the earth and in heaven, of which effects they can by no means see the causes and therefore think that they are wrought by divine power. For which reasons, when we shall have clearly seen that NOTHING CAN BE PRODUCED FROM NOTHING, we shall then have a more accurate perception of that of which we are in search, and shall understand whence each individual thing is generated, and how all things are done without the agency of the gods.

For if things came forth from nothing, every kind of thing might be produced from all things; nothing would require seed. In the first place, men might spring from the sea; the scaly tribe, and birds, might spring from the earth; herds, and other cattle, might burst from the sky; the cultivated fields, as well as the deserts, might contain every kind of wild animal, without any settled law of production: nor would the same fruits be constant to the same trees, but would be changed; and all trees might bear all kinds of fruit. Since, when there should not be generative elements for each production, how could a certain parent-producer remain invariable for all individual things? But now, because all things are severally produced from certain seeds, each is produced, and comes forth into the regions of light, from that spot in which the matter, and first elements of each, subsist. And for this cause all things cannot be produced from all, inasmuch as there are distinct and peculiar faculties in certain substances.

Besides, why do we see the rose put forth in spring, corn in summer heat, and vines under the influence of autumn, if it be not because, when the determinate seeds of things have united together at their proper time, whatever is produced appears while the seasons are favorable, and while the vigorous earth securely brings forth her tender productions into the regions of light. But if these were generated from nothing, [p.264] they might arise suddenly at indefinite periods, and at unsuitable seasons of the year, inasmuch as there would be no original elements, which might be restrained from a generative combination at any season, however inconvenient.

Nor, moreover, would there be need of time for the coming together of seed for the growth of things, if they could grow out of nothing. For young men might on a sudden be formed from puny infants, and groves, springing up unexpectedly, might dart forth from the earth; of which things it is plain that none happen, since all things grow gradually, as is fitting, from unvarying atoms, and, as they grow, preserve their kind, so that you may understand that all things individually are enlarged and nourished from their own specific matter.

Add to this, that the earth cannot furnish her cheering fruits without certain rains in the year; nor, moreover, can the nature of animals, if kept from food, propagate their kind, and sustain life; so that you may rather deem that many elements are common to many things, (as we see letters common to many words), than that any thing can exist without its proper elements.

Still further, why could not nature produce men of such a size that they might ford the sea on foot, and rend great mountains with their hands, and outlast in existence many ages of human life, if it be not because certain matter has been assigned for producing certain things, from which matter it is fixed what can or cannot arise? It must be admitted therefore, that nothing can be made from nothing, since things have need of seed, from which all individually being produced, may be brought forth into the gentle air of heaven.

Lastly, since we observe that cultivated places excel the uncultivated, and yield to our hands better fruits, we may see that there are in the ground the primitive elements of things, Which we, in turning the fertile glebe with the ploughshare, and subjugating the soil of the earth, force into birth. But were there no such seeds, you might see things severally grow up and become much better of their own accord without our labor.

Add, too, that nature resolves each thing into its own constituent elements, and DOES NOT REDUCE ANY THING TO NOTHING.

For if any thing were perishable in all its parts, every thing might then dissolve, being snatched suddenly from before our eyes; for there would be no need of force to produce a separation of its parts, and break their connexion. Whereas now, since all things individually consist of eternal seed, nature does not suffer the destruction of any thing to be [p.265] seen, until such power assail them as to sever them with a blow, or penetrate inwardly through the vacant spaces, and dissolve the parts.

Besides, if time utterly destroys whatever things it removes through length of age, consuming all their constituent matter, whence does Venus restore to the light of life the race of animals according to their kinds? Whence does the variegated earth nourish and develop them, when restored, affording them sustenance according to their kinds? Whence do pure fountains, and eternal rivers flowing from afar, supply the sea? Whence does the aether feed the stars? For infinite time already past, and length of days, ought to have consumed all things which are of mortal consistence: but if those elements, of which this sum of things consists and is renewed, have existed through that long space, and that past duration of time, they are assuredly endowed with an immortal nature. Things therefore cannot return to nothing.

Further, the same force and cause might destroy all things indiscriminately, unless an eternal matter held them more or less bound by mutual connexion. For a mere touch, indeed, would be a sufficient cause of destruction, supposing that there were no parts of eternal consistence, but all perishable, the union of which any force might dissolve. But now, because various connexions of elements unite together, and matter is eternal, things continue of unimpaired consistence, until some force of sufficient strength be found to assail them, proportioned to the texture of each. No thing, therefore, relapses into non-existence, but all things at dissolution return to the first principles of matter.

Lastly, you may say, perhaps, the showers of rain perish, when Father aether has poured them down into the lap of Mother Earth. But it is not so; for hence the smiling fruits arise, and the branches become verdant on the trees; the trees themselves increase, and are weighed down with produce. Hence, moreover, is nourished the race of man, and that of beasts; hence we see joyous cities abound with youth, and the leafy woods resound on every side with newly fledged birds; hence the weary cattle, sleek in the rich pastures, repose their bodies, and the white milky liquor flows from their distended udders; hence the new offspring gambol sportive, with tottering limbs, over the tender grass, their youthful hearts exhilarated with pure milk. Things, therefore, do not utterly perish, which seem to do so, since Nature recruits one thing from another, nor suffers any thing to be produced, unless its production be furthered by the death of another.

Attend, now further: since I have shown that things cannot be produced from nothing, and also that, when produced, they cannot return to nothing, yet, lest haply thou shouldst begin to distrust my words, because the primary particles of things cannot be discerned by the eye, hear, in addition, what substances thou thyself must necessarily confess to exist, although impossible to be seen.

In the first place, the force of the wind, when excited, lashes the sea, agitates the tall ships, and scatters the clouds; at times, sweeping over the earth with an impetuous hurricane, it strews the plains with huge trees, and harasses the mountain-tops with forest-rending blasts; so violently does the deep chafe with fierce roar and rage with menacing murmur. The winds, then, are invisible bodies, which sweep the sea, the land, the clouds of heaven, and, agitating them, carry them along with a sudden tornado. Not otherwise do they rush forth, and spread destruction, than as when a body of liquid water is borne along in an overwhelming stream, which a vast torrent from the lofty mountains swells with large rain-floods, dashing together fragments of woods and entire groves; nor can the strong bridges sustain the sudden force of the sweeping water, with such overwhelming violence does the river, turbid with copious rain, rush against the opposing mounds; it scatters ruin with a mighty uproar, and rolls huge rocks under its waters; it rushes on triumphant wheresoever any thing opposes its waves. Thus, therefore, must the blasts of the wind also be borne along; which (when, like a mighty flood, they have bent their force in any direction) drive all things before them, and overthrow them with repeated assaults, and sometimes catch them up in a writhing vortex and rapidly bear them off in a whirling hurricane. Wherefore, I repeat, the winds are substances, though invisible, since in their effects, and modes of operation, they are found to rival mighty rivers, which are of manifest bodily substance.

Moreover we perceive various odors of objects, and yet never see them approaching our nostrils. Nor do we behold violent heat, or distinguish cold with our eyes; nor are we in the habit of viewing sounds; all which things, however, must of necessity consist of a corporeal nature, since they have the power of striking the sense: FOR NOTHING, EXCEPT BODILY SUBSTANCE, CAN TOUCH OR BE TOUCHED.

Further, garments, when suspended upon a shore on which waves are broken, grow moist; the same, when spread out in the sun, become dry; yet neither has it been observed how the moisture of the water settled in them, nor, on the other hand, how it escaped under the influence of the heat. The moisture, therefore, is dispersed into minute particles, which our eyes can by no means perceive.

Besides, in the course of many revolutions of the sun, a ring upon the finger is made somewhat thinner by wearing it; the fall of the drop from the eaves hollows a stone; the crooked share of the plough, though made of iron, imperceptibly decreases in the fields; even the stone pavements of the streets we see worn by the feet of the multitude; and the brazen statues, which stand near the gates, show their right hands made smaller by the touch of people frequently saluting them, and passing by. These objects, therefore, after they have been worn, we observe to become diminished; but what particles take their departure on each particular occasion, jealous nature has withheld from us the faculty of seeing.

Lastly, whatever substances time and nature add little by little to objects, obliging them to increase gradually, those substances no acuteness of vision, however earnestly exerted, can perceive; nor, moreover, whatever substances waste away through age and decay; nor can you discern what the rocks, which overhang the sea, and are eaten by the corroding salt of the ocean, lose every time that they are washed by the waves. Nature, therefore, carries on her operations by imperceptible particles.

Now, however, are all things held enclosed by corporeal substance; for there is a VOID in things; a truth which it will be useful for you, in reference to many points, to know; and which will prevent you from wandering in doubt, and from perpetually inquiring about the ENTIRE OF THINGS, and from being distrustful of my words. Wherefore, I say, there is space INTANGIBLE, EMPTY, and VACANT. If this were not the case, things could by no means be moved; for that which is the quality of body, namely, to obstruct and to oppose, would be present at all times, and would be exerted against all bodies; nothing, therefore, would be able to move forward, since nothing would begin to give way. But now, throughout the sea and land and heights of heaven, we see many things moved before our eyes in various ways and by various means, which, if there were no void, would not so much want their active motion, as being deprived of it, as they would, properly speaking, never by any means have been produced at all; since matter, crowded together on all sides, would have remained at rest, and have been unable to act.

Besides, although some things may be regarded as solid, yet you may, for the following reasons, perceive them to be of a porous consistence. In rocks and caves, the liquid moisture of the waters penetrates their substance, and all parts weep, as it were, with abundant drops; food distributes itself through the whole of the body in animals; [p.268] the groves increase, and yield their fruits in their season, because nourishment is diffused through the whole of the trees, even from the lowest roots, over all the trunks and branches; voices pass through the walls, and fly across the closed apartments of houses; keen frost penetrates to the ivory marrow of our bones; which kind of effects, unless there were void spaces in bodies, where the several particles might pass, you would never by any means observe to take place.

Lastly, why do we see some things exceed other things in weight, though of no greater shape and bulk? For, if there is just as much substance in a ball of wool as there is in a ball of lead, it is natural that they should weigh the same, since it is the property of all bodily substance to press every thing downwards; but the nature of a VOID, on the contrary, continues without weight. That body, therefore, which is equally large with another, and is evidently lighter, shows plainly that it contains a greater portion of VACUITY. But the heavier body, on the Other hand, indicates that there is in it more material substance, and that it comprises much less empty space.

That, therefore, which we are now, by the aid of searching argument, investigating, that, namely, which we call VOID, is doubtless mixed among material substances.

In considering these matters, I am obliged to anticipate that objection which some imagine, lest it should seduce you from the truth. They say, for instance, that water yields to fishes pushing forwards, and opens liquid passages, since the fish leave spaces behind them, into which the yielding waters may make a conflux; so also that other things may be moved among themselves, and change their place, although all parts of space be full. But this notion, it is evident, has been wholly conceived from false reasoning. For in what direction, I pray, will fish be able to go forward, if the water shall not give them room? Or in what direction, moreover, will the water have power to yield, supposing the fish shall have no power to go forward to divide it? Either, therefore, we must deny motion to all bodies whatsoever, or we must admit that vacuity is more or less inherent in all material substances, whence every thing that moves derives the first commencement of its motion.

Lastly, if two broad and flat bodies, after having come into collision, suddenly start asunder, it is clear that air must necessarily take possession of all the vacuum which is then formed between the bodies. And further, although that air may quickly unite to flow into the vacancy, with blasts blowing rapidly from all sides, yet the whole space will not be able to be filled at once; for the air must of necessity occupy some [p.269] part first, then another, till in succession all parts be occupied.

But if any person perchance, when the bodies have started asunder, thinks that that separation is thus effected by reason that the air condenses itself, he is in error; for a vacuum is then formed between the bodies, which was not there before, and the part likewise behind the bodies, which was vacant before, is filled; nor can air be condensed in such a way; nor, even if it could, would it have the power, I think, to draw itself into itself, and unite its particles together without the aid of a void. For which reason, although you may long hesitate, alleging many objections, you must nevertheless at last confess that there is vacuum in bodies.

I have the ability, moreover, to collect credit for my doctrines, by adducing many additional arguments. But these small traces which I have indicated will be sufficient for a sagacious mind; traces by which, indeed, you yourself may discover others. For as dogs, when they have once lighted upon certain tracks on the path, very frequently find by their scent the lair of a wild beast that ranges over the mountains, though covered over with leaves; so you yourself will be able, in such matters as these, to note, of your own sagacity, one principle after another, and to penetrate every dark obscurity, and thence to elicit truth.

But if you shall be slow to assent, Oh Mererufus, or you shall at all shrink back from the subject, I can still certainly give you the following assurance. My tongue, so agreeable to you, will have the power of pouring forth from my well-stored breast such copious draughts from mighty sources, that I fear lest slow old age may creep over our limbs, and break down the gates of life within us, before all the abundance of arguments in my verses, concerning any one subject, can have been poured into your ears. But now, that I may resume my efforts to complete in verse the weaving of the web which I have begun, give me a little more of your attention.

As it is, therefore, all nature of itself has consisted, and consists, of two parts; for there are bodily substances, and vacant space, in which these substances are situate, and in which they are moved in different directions. For the common perception of all men shows that there is corporeal consistence; of the existence of which, unless the belief shall be first firmly established, there will be no principle by reference to which we may succeed, by any means whatever, in setting the mind with argument concerning matters not obvious to sense.

To proceed then, if there were no place, and no space which we call vacant, bodies could not be situated any where, nor could at all move [p.270] any whither in different directions; a fact which we have shown to you a little before.

Besides, there is nothing which you can say is separate from all bodily substance, and distinct from empty space; which would, indeed, be as it were a third kind of nature. For whatsoever shall exist, must in itself be something, either of large bulk, or ever so diminutive, provided it be at all; when, if it shall be sensible to the touch, however light and delicate, it will increase the number of bodies, and be ranked in the multitude of them; but if it shall be intangible, inasmuch as it cannot hinder in any part any object proceeding to pass through it, it then, you may be sure, will be the empty space which we call a vacuum.

Moreover, whatsoever shall exist of itself, will either do something, or will be obliged TO SUFFER other things acting upon it, or will simply BE, so that other things may exist and be done in it. But nothing can DO OR SUFFER without being possessed of bodily substance, nor, moreover, afford place for acting and suffering, unless it be empty and vacant space. No third nature, therefore, distinct in itself, besides vacant space and material substance, can possibly be left undiscovered in the sum of things; no third kind of being, which can at any time fall under the notice of our senses, or which any one can find out by the exercise of his reason.

For whatsoever other things are said to be, you will find them to be either necessary ADJUNCTS of these two things, or accidents of them. A necessary ADJUNCT is that which can never be separated and disjoined from its body without a disunion attended with destruction to that body; as the weight of a stone, the heat of fire, the fluidity of water; sensibility to touch in all bodies, insensibility to touch in empty space. On the other hand, such things as slavery, poverty, riches, liberty, war, concord, and other things, by the coming or going of which the nature of the subject affected remains uninjured, these we are accustomed (as is proper) to call ACCIDENTS.

Time, likewise, is not an existence in itself, but it is merely our understanding that collects from things themselves what HAS BEEN DONE in the past age; what also IS PRESENT; what, moreover, MAY FOLLOW afterwards. And it must be owned that no one has conceived of time existing by itself apart from progressive motion and quiet rest.

Moreover, when writers say that Helen WAS carried off, and that the Trojan people WERE subdued in war, we must take care lest, perchance, those writers induce us to admit that those events, viz., the abduction of Helen and the subjugation of the Trojans, WERE of [p.271] themselves; when time, irrevocably past, has carried away those generations of men, of whom these transactions were the events or accidents. For whatever shall have been done, will probably be called an event or accident, whether occurring to lands, or to legions (that is, men) themselves.

Furthermore, if there were not this bodily substance in things, nor this room and space in which all things severally are done, the flame lighted up by the love of Helen’s beauty, spreading through the breast of the Phrygian Paris, would never have kindled the famous contests of cruel warfare; nor would the wooden horse have secretly set fire to the citadel of the Trojans by a nocturnal delivery of Greeks. So that you may plainly see that all transactions whatsoever do not CONSIST or EXIST of themselves, as body does, nor are spoken of as existing in the same way as a vacuum exists; but rather that you may justly call them events or accidents of body, or of space in which all transactions are brought to pass.

Bodies, besides, are partly original elements of things, and partly those which are formed of a combination of those elements. But those which are elements of things, no force can break; for they successfully resist all force by solidity of substance; although, perhaps, it seems difficult to believe that any thing of so solid a substance can be found in nature; for the lightning of heaven passes through the walls of houses, as also noise and voices pass; iron glows, being penetrated by heat, in the fire; rocks often burst with fervent heat; the hardness of gold, losing its firmness, is dissolved by heat; the icy coldness of brass, overcome by flame, melts; heat, and penetrable cold, enter into the substance of silver, for we have felt both with the hand, when, as we held silver cups after our fashion, water was poured into them from above; so that, as far as these instances go, there seems to be nothing solid in nature. But because, however, right reason, and the nature of things, compel me to hold a contrary opinion, grant me your attention a while, until I make it plain, in a few verses, that there really exist such bodies as are of a solid and eternal corporeal substance; which bodies we prove to be seeds and primary particles of things, of which the whole generated universe now consists.

Furthermore, since in things which are produced, or compounded of matter, there is found empty space, solid matter must exist around it; nor can any thing be proved by just argument to conceal vacuity, and to contain it within its body, unless you admit that that which contains it is a solid. But that solid can be nothing but a combination of matter, such as may have the power of keeping a vacuity enclosed. That matter, therefore, which consists of solid body, may be eternal, while other substances, which are only compounds of this matter, may be dissolved.

In addition, too, if there were no space to be vacant and unoccupied, all space would be solid. On the other hand, unless there were certain bodies to fill up completely the places which they occupy, all space, which any where exists, would be an empty void. Body, therefore, is evidently distinct from empty space, though each has its place alternately; since all space neither exists entirely full, nor, again, entirely empty. There exist, therefore, certain bodies which can completely fill the places which they occupy, and distinguish empty space from full.

These bodies, which thus completely fill space; can neither be broken in pieces by being struck with blows externally, nor, again, can be decomposed by being penetrated internally; nor can they be made to yield if attempted by any other method; a principle which we have demonstrated to you a little above; for neither does it seem possible for any thing to be dashed in pieces without a vacuum, nor to be broken, nor to be divided into two by cutting; nor to admit moisture, nor, moreover, subtle cold, nor penetrating fire, by which operations and means all things compounded are dissolved. And the more any thing contains empty space within it, the more it yields when thoroughly tried by these means. If, therefore, the primary atoms are solid and without void, they must of necessity be eternal.

Again, unless there had been eternal matter, all things, before this time, would have been utterly reduced to nothing; and whatsoever objects we behold would have been reproduced from nothing. But since I have shown above, that nothing can be produced from nothing, and that that which has been produced cannot be resolved into nothing, the primary elements must be of an imperishable substance, into which primary elements every body may be dissolved, so that matter may be supplied for the reproduction of things. The primordial elements, therefore, are of pure solidity; nor could they otherwise, preserved, as they have been, for ages, repair things, as they have done, through that infinite space of time which has elapsed since the commencement of this material system.

Besides, if nature had set no limit to the destruction of things, the particles of matter would, by this time, have been so reduced, by reason of every former age wasting them, that nobody compounded of them could, from any certain time, however remote, reach full maturity of existence. For we see that any thing may be sooner taken to pieces than put together again; for which reason, that which the infinitely long [p.273] duration of all past time had broken into parts, disturbing and dissevering it, could never be repaired in time to come. But now, as is evident, there remains appointed a certain limit to destruction, since we see every thing recruited, and stated portions of time assigned to every thing according to its kind, in which it may be able to attain full vigor to its kind, in which it may be able to attain full vigor of age.

To this is added, that though the primary particles of matter are perfectly solid, yet that all things, which are formed of them, may be rendered soft and yielding, as air, water, earth, fire (in whatever way they may be produced, and by whatever influence they may be directed); but this happens because there is vacant space intermingled with the substance of things compounded. But, on the other hand, if the primordial elements of things were soft, how strong flints and iron could be produced, no explanation could be given, for, by this supposition, nature will be deprived of all possibility of commencing a foundation. The primordial elements, therefore, are endowed with pure solidity; by the dense combination of which all compound bodies may be closely compacted, and exhibit powerful strength.

Moreover, if you still persist to say that no limit has been appointed to the dissolution of bodies, you will then, however, have to allow that there must remain certain dissoluble bodies in the world, which have not yet been assailed with any trial of their strength. But since dissoluble bodies are endued only with a fragile nature, it is inconsistent to suppose that they could have lasted through an infinite course of time, if they had been harassed, age after age, with innumerable assaults.

Further, since also a limit has been assigned for the growth of things according to their kinds, and for their support of life; and since it is established by the laws of Nature what each kind can or cannot do; and since nothing is changed, but all things remain constant to such a degree, that even the birds of different plumage, all in succession, show, existing upon their bodies, spots distinctive of their species; we must grant that such bodies must have in them an immutable material substance. For if the primitive particles of things could be changed, by being successfully wrought upon in any way, it would then also become uncertain what might or might not arise into being; it would be uncertain, moreover, how far limited power, and a firmly fixed boundary, is set to each kind; nor, with such a possibility of alteration, would the tribes of animals, according to their kinds, be so constantly able to reproduce the nature, motions, mode of life, and habits of their progenitors.

Again, since even of such a body as our senses cannot perceive, [p.274] there is yet a certain extreme point, whatever it be, that point certainly exists without parts, and consists of the least possible natural substance; nor has it ever existed of itself, apart from its body, nor will it hereafter be able so to exist, since it is itself the first and last part of another body; after which other and other like parts in succession fill up, in a condensed mass, the substance of the body, which parts, since they cannot consist by themselves, must of necessity adhere to something else, from which they can by no means be detached.

Primordial atoms are therefore of pure solidity, which, composed of the smallest points, closely cohere; not combined of a union of any other things, but rather endowed with an eternal, simple, and indissoluble existence, from which nature allows nothing to be broken off, or even diminished, reserving these primordial atoms as seeds for her productions.

Moreover, unless there shall be some LEAST, some point where division ends, the smallest bodies will individually consist of infinite parts, as, in that case, any part of the half of any body will always have its own half; nor will any thing set a limit to this division. What, therefore, will be the difference in their nature between the greatest and smallest of bodies? It will not be possible that there should be any difference; for though the whole entire sum of things, or the Universe, be infinite, yet the smallest things which exist in it will equally consist of infinite parts. To which position since just reasoning is opposed, and denies that the mind can admit it, you must be prevailed upon to acknowledge that there are bodies which exist having no parts, and consist of the least possible substance; and since they are so, since they are indivisible and undiminishable, you must also concede that they are solid and eternal.

Further, unless Nature, the producer of things, had been accustomed to force all things to be resolved into minutest parts, the same Nature would now be unable to recruit any thing from those parts; because those generated bodies which are augmented and repaired by no parts, cannot have and retain unimpaired those affections which generative matter ought to have, namely, various connexions, weights, concussions, combinations, movements, by which things are severally brought to pass.

Translation of John Selby Watson

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Chicago: Lucretius, Principles of the Atomic Theory in The Library of Original Sources, ed. Oliver J. Thatcher (Milwaukee, WI: University Research Extension Co., 1907), 263–274. Original Sources, accessed May 20, 2024,

MLA: Lucretius. Principles of the Atomic Theory, in The Library of Original Sources, edited by Oliver J. Thatcher, Vol. 3, Milwaukee, WI, University Research Extension Co., 1907, pp. 263–274. Original Sources. 20 May. 2024.

Harvard: Lucretius, Principles of the Atomic Theory. cited in 1907, The Library of Original Sources, ed. , University Research Extension Co., Milwaukee, WI, pp.263–274. Original Sources, retrieved 20 May 2024, from