Lucretius, a materialist philosopher of the 1st century BC.   His surviving work “On The Nature of Things” is a book which is very relevant to modern thought.   His basic premise is that the atom is eternal, and all things form by the rearrangement of existing atoms.   He rejects some of the sillier claims such as “fire” being one of the elements, rather insisting it is made of of atoms itself.     His words for atoms are “primordial elements”, “seeds”, “generating bodies”,   and the like.    As you read through his work it becomes clear he is a steady state cosmologist, he assumes the atom cannot be broken apart.  Modern thought is slightly different in that we generally view the hot big bang origin of matter [with some exceptions], and after the first few moments past that event the atoms and laws of physics settled down into what we have today.  With that caveat lets proceed into Lucretius.

I provide some of his quotes here :

For I will begin to set down for you the highest matters of heaven and gods, and I will disclose the first principles of matter, the ones nature uses to produce, increase, sustain all things, and into which she converts them once more, when they disintegrate. These things, in explanatory accounts of them, we are accustomed to call “materials” and “the generating bodies of things”— to name them “seeds of things,” using the term “primordial elements,” since they come first, and from these things all objects are derived.

For if men could perceive there is a set limit to their troubles, they would, with some reason, have strength enough to resist religion and prophets’ threats. But now, since we must fear that, when we die, we will be punished for eternity, there is no means, no possibility, of fighting back. For people do not know the nature of the soul—whether it is born with them, or, by contrast, is inserted at their birth, whether it perishes with us, dissolved in death, or whether it visits the shades of Orcus, his enormous pools, or whether, as our Ennius said in song, it sets itself, by divine influence, in other animals.

And so we must with proper reasoning look into celestial matters—explain the reasons for the wandering of the sun and of the moon, the force which brings about everything that happens on the earth; and, in particular, we must employ keen reasoning, as well, to look into what makes up the soul, the nature of mind, and what it is that comes into our minds and terrifies us when we are awake and suffering some disease or in deep sleep, so that we seem to see and hear right there, before our eyes, those who have met their deaths, whose bones the earth now holds in its embrace.

And so we will start to weave her first principle as follows: nothing is ever brought forth by the gods from nothing. That is, of course, how, through fear, all mortal men are held in check—they view many things done on earth and in the sky, effects whose causes they cannot see at all, and so they assume that such things happen because of gods. Hence, once we understand that nothing can be produced from nothing, then we shall more accurately follow what we are looking for,

Above we see the template.   Lucretius will explain the origins of all we see, by appealing to the eternal matter of the atomic elements.   He will explain how the world and universe built from these things functions.  In doing so he will remove the mysteries and thus remove the need for faith and religion.

Note I am using the word atomic here.  When you read the rest of his work however his idea of these seeds/elements is fully consistent with the notion of the atom in a way that is simply stunning.   Of course in his view the atom is not able to be destroyed, whereas today we can and have moved on to studying the components of the atom itself.

For if things were made from nothing, each type could be produced from any other thing,

To this we can also add that nature dissolves all things back again into their own elements and does not turn matter into nothing.

When they are restored, how does artful earth offer them food, nourish, and strengthen them, meeting each one’s needs? How do its own springs and distant rivers flowing far and wide keep the sea supplied? How does the aether feed the stars? The infinity of time and days gone by should have destroyed all things made up of mortal elements. But if those particles which make up and renew the total sum of things have been around though all the ages of those years long past, then we can be assured they do possess an immortal nature. And thus, no things can be converted back into nothing.

The fact that all comes from these eternal elements, and then returns to them, infers there are laws and processes to govern the origin of all things.   Thus not only what is necessary for any “gods” to do is not only limited in scope but also what they are able to do.   Things cannot simply appear and disappear as if by magic.

Thus, there is no substance which is reduced to nothing—but all things, once dissolved, go back to material stuff.

However, nature does not hold all things in corporeal matter densely packed on every side. For in material stuff there is a void—in many instances a useful point to know; it will not let you roam around in doubt, always seeking out the total sum of things and losing faith in what I say. So, then, there is a void— intangible, empty, vacant. If not, if this were not there, there would be no way that anything could move, because substance has this property—it stands in the way, it obstructs—this would be present in it all the time, acting against everything. Therefore, nothing at all could move forward, since nothing else would first make room for it by giving way. But now, on sea and land, and in the celestial sky, we notice before our eyes many things being shifted in various ways by various means, and these, if there were no void, would not so much lack restless motion, of which they were deprived, as have no means at all of being born, since matter, everywhere a compact mass, would have remained inert.

And then, why do we see some things weigh more than other things, when there is no difference in their size? For if in a ball of wool there is just as much matter as in lead, they should weigh the same, since material stuff has the property of pushing all things down, but, by contrast, the nature of a void continues on without weighing anything. And so, the object which is just as large and yet seems lighter clearly demonstrates that it contains in it more empty space; whereas, the heavier object indicates that it has more material stuff inside and far less void. Thus, there can be no doubt the thing which we, with our keen argument, are seeking out, what we describe as void, exists, mixed in with substantial matter are made up of two things, material substances and empty space in which these substances are placed and move in various directions.

Matter exists— sense perception shared by all tells us that. If faith in sense is not first firmly set, if it does not prevail, there is nothing to which we can appeal in what we claim, by any form of mental reasoning, about the truth of things we cannot see.

Moreover, there is nothing you can claim is separate from all matter and distinct from empty space—some third form of nature, as it were, which someone might discover. Whatever will exist, must, in itself, be something. No matter how large or small its size may be, so long as it exists, if it can make contact, however slight and delicate, it will increase the sum of substantial things and be included in the total. If it cannot be touched, cannot, in any of its parts, prevent matter in motion from passing through it, quite clearly it will be that empty space we call void. Furthermore, whatever stuff inherently exists, will have to act or else to suffer when other matter acts upon it, or else it will be there so matter can exist and act in it. But nothing can act and be acted on unless it has corporeal substance, and nothing can offer room for motion unless it is empty, vacant space. Thus, apart from void and matter, there can be, in the whole sum of things, no third nature.

The universe is made of two things, elemental matter and void.   The density and rigidity of the elemental matter impacts everything about what we see.   The exclusion of “third nature” was to exclude any mystical third kinds of things that were often invoked to explain the spiritual.   For example Lucretius, not in the quotes above, allows only for corporeal matter which limits his definition of matter.  In Lucretius model light is particle, hence light is matter, thus energy is particle based.

Furthermore, if material stuff had not been eternal, all things would have been utterly reduced to nothing long ago

Thus, elements are entirely solid—since otherwise there is no way they could have been preserved through ages of infinite time till now, in order to restore things once again.

we can be sure as well that things must have a body of unchanging matter. For if the primordial elements of things could, in any way, be overpowered and changed, then we would also have no certainty about what could or could not come to be

for the same elements make up sky, sea, lands, rivers, and the sun, the same elements form crops, trees, animals— but moving and combined with different ones in different ways.

Firstly, because I teach important things and seek to free the mind from constricting fetters of religion. And then because the verses I compose about dark matters are so luminous, investing all things with poetic grace. And that, too, does not seem unreasonable. For just as healers, when they try to give young children foul-tasting wormwood, first spread sweet golden liquid honey round the cup, so at this age the unsuspecting child, with honey on his lips, may be deceived and in the meantime swallow down the drink of bitter gall—he may have been misled, but he is not hurt—with this deception he may be restored instead, grow stronger. In the same way now, since this reasoning seems generally too bitter for those men who have not tried it and the common crowd shrinks back in fear, I wanted to explain my argument to you in these verses, sweet-spoken Pierian song, as if I were sprinkling it with poetry’s sweet honey, if, with such a method, I could perhaps get your attention on my verse, until you perceive the entire nature of things— how it is shaped and what its structure is

Lucretius infers by reason that the elements must be eternal.   With his assumption of an eternal universe whatever these elements are they would have been worn away to nothing had they not been eternal by the normal processes of erosion/entropy/etc.   No matter how slight those effects, the eternal steady state universe means they would have vanished had they not been eternal.

He will use poetry to explain his ideas, granted his poetry mostly vanishes in translation, but he is writing this work to the emperor as well as other non scientific folks.  So he attempts to make it appealing so they will listen.

And here I will leave Lucretius for now.   This post simply lays the framework for his later discussions.  In a later post I will looks at how he explains the cosmos.  The parallels in that to modern ideas is nothing short of stunning.