Letters and Principal Doctrines

Epicurus to Herodotus, greetings.note

For those who can’t work through every detail of what I have written on nature, Herodotus, or study closely the longer books I have composed, I have myself prepared an epitome of the whole system, enough to keep the most general doctrines in memory, so that on every occasion they can help themselves on the most important points, to the extent that they take up the study of nature. And even those who have made good progress in surveying the whole must remember the outline of the entire system, laid out in its elements. For we often need the comprehensive view; the detailed one, not so often.

So we must keep returning to those general principles, and fix enough of them in memory that the most decisive grasp of the facts will come from it, and indeed every detailed precision will be discovered too, once the most general outlines are well understood and remembered. Even for someone fully trained, the most decisive thing in all precise knowledge is this: being able to use one’s grasp of things quickly, with each point brought back to simple elements and formulas. For no one can hold the condensed sum of a continuous survey of the whole who cannot take in within himself, in brief formulas, everything that might also be worked out in detail.

A method of this kind is useful to everyone at home in the study of nature. So I, who urge continual activity in the study of nature and who above all find calm for my life in such activity, have made for you this epitome as well, an elementary summary of the doctrines as a whole.

First, then, Herodotus, we must grasp what underlies our words, so that we can refer to it and judge what is believed, investigated, or puzzled over, and so that everything isn’t left undecided as we go on demonstrating to infinity, or our words aren’t empty. X 38 For the primary concept corresponding to each word must be seen plainly and need no further demonstration, if we are to have something to which we can refer what is investigated, puzzled over, or believed.

Next, we must check everything by our sensations, and simply by our present apprehensions, whether of the mind or of any of the criteria whatever, and likewise by the feelings we actually have, so that we have signs by which to infer both what awaits confirmation and what is not evident.note

With these distinctions made, we can now consider what is not evident. First, nothing comes into being from what is not. For then anything would come from anything, with no need of seeds. X 39 And if what vanishes were destroyed into what is not, all things would have perished, since what they dissolved into would not exist. Moreover, the universe always was such as it is now, and always will be. For there is nothing into which it could change: besides the universe there is nothing that could enter into it and bring about the change.

Further [he says this also at the beginning of the Big Epitome and in book 1 of On Nature], the universe is bodies and void. That bodies exist, sensation itself testifies in every case, and it is by sensation that reason must judge what is not evident. X 40 And if there were not what we call void, space, and intangible nature, bodies would have nowhere to be and nothing to move through, as they are plainly seen to move. Beyond these, nothing can even be conceived, either by direct grasp or by analogy with what is so grasped, as a complete nature in its own right, rather than as what we call the properties or accidents of these.note

Moreover, of bodies [this also in book 1 of On Nature, in books 14 and 15, and in the Big Epitome] some are compounds, and others are the things from which compounds are made. X 41 These are indivisible and unchangeable, if all things are not to be destroyed into what is not, but are to remain strong when compounds dissolve, being full by nature and having no place or way in which they could be dissolved. So the first principles must be indivisible kinds of body.note

Moreover, the universe is unlimited. For what is limited has an extremity, and an extremity is observed against something else. But the universe is not observed against anything else. So, having no extremity, it has no limit; and having no limit, it would be unlimited and not limited.

Moreover, the universe is unlimited both in the number of its bodies and in the extent of its void. X 42 For if the void were unlimited and the bodies limited, the bodies would not stay anywhere but would be carried along, scattered through the unlimited void, with nothing to support them or check them by collision. And if the void were limited, the unlimited bodies would have no room to be in.

Besides this, the bodies that are indivisible and solid, from which compounds come into being and into which they dissolve, have a number of different shapes beyond our grasp. For so many differences could not arise from the same shapes if their number could be grasped. And for each shape the atoms alike in it are simply unlimited, but in their differences they are not simply X 43 unlimited, only beyond our grasp [for he says further on that division does not go on to infinity. He says this since qualities change, unless one is simply going to extend atoms to infinity in size as well].

The atoms move continuously [he says further on that they also move at equal speed, since the void gives way equally to the lightest and the heaviest] for all time. Some rebound far apart from one another, while others keep up a vibration in place, when they happen to be locked in by their entanglement or enclosed by atoms that interlock.

For the nature of the void, which separates each atom by itself, brings this about, since it cannot offer support; and the solidity the atoms have produces the rebound in collision, to whatever extent the entanglement allows recovery from the collision. There is no beginning to these things, since the atoms and the void are eternal. [He says further on that atoms have no quality besides shape, size, and weight; and in the Twelve Elements he says that color changes with the arrangement of the atoms. Also that atoms do not come in every size: at any rate, no atom has ever been seen by sensation.]

A statement as brief as this, if all these points are remembered, provides an adequate outline for thinking about the nature of what exists.

Moreover, there are unlimited worlds, some like this one and some unlike it. For the atoms, being unlimited, as was just shown, are carried even to the farthest distances. And atoms of the kind from which a world might come into being, or by which it might be made, have not been used up on one world or on a limited number of worlds, whether like this one or different from it. So nothing stands in the way of there being unlimited worlds.

Moreover, there are impressions shaped like solid bodies, far finer than visible things. For it isn’t impossible that such formations arise in the surrounding space, or that conditions arise suited to producing hollow and fine surfaces, or that effluences arise which keep the same sequence of position and arrangement they had in the solid bodies. These impressions we call images. Moreover, motion through the void, when it meets nothing that collides with it, covers any conceivable distance in an inconceivably short time. For collision and its absence take on the likeness of slowness and speed.note

Yet the moving body itself does not arrive at several places at once in the times observable by reason, for that is unthinkable. And when, in perceptible time, it arrives along with the rest from whatever point in the unlimited, it will not be departing from the place from which we perceive its motion. For its departure will be like a collision, even if up to that point we leave the speed of its motion unchecked by collision. It is useful to hold on to this element too. Next, nothing in what appears contradicts the claim that the images have an unsurpassable fineness. Hence they also have unsurpassable speeds, since every passage fits them, so that nothing, or little, collides with their unlimited stream, whereas a body made of many, even unlimited, atoms at once meets some collision.

Besides this, images are formed as fast as thought. For there is a continuous flow from the surface of bodies, not revealed by any shrinking because of replenishment, which preserves for a long time the position and order the atoms had in the solid body, though sometimes it is confused; and there are formations in the surrounding space that come together swiftly, since they don’t need to be filled out in depth; and there are certain other ways in which natures of this kind are produced. None of this is contradicted by the sensations, if one looks at how clear evidence works, so as to trace back to us the correspondences with things outside.

We must also hold that it is when something enters us from outside that we see and think. For external things would not stamp their own nature of color and shape on us through the air between us and them, nor through rays or currents of any kind passing from us to them, as well as they do through certain impressions that enter us from the objects, alike in color and shape, of a size to fit our sight or our mind, and moving rapidly. X 50 Then, for this reason, they give the presentation of a single continuous thing, and they preserve their correspondence with the underlying object through the proportionate pressure from it, which comes from the vibration of the atoms deep within the solid body.

For the resemblance of appearances—whether received as in a picture, or arising in sleep, or through some other acts of apprehension by the mind or the other criteria—to the things we call existing and true would never occur unless there were also such things for us to compare them with. And error would not occur unless we also experienced another motion in ourselves, connected with the act of presentation but distinct from it. By this motion, if something is not confirmed or is contradicted, falsehood arises; if it is confirmed or not contradicted, truth.

So we must hold firmly to this doctrine too, so that the criteria based on clear evidence are not destroyed, and error is not made just as firm and does not throw everything into confusion.

Moreover, hearing occurs when a current is carried from something that speaks, rings, crashes, or in any way produces the experience of hearing. This current is scattered into particles of like parts, which at the same time keep a certain correspondence with one another and a distinctive unity reaching back to the source; this unity generally produces perception of the source, or, failing that, at least makes evident that there is something outside. X 53 For without some correspondence carried back from there, such perception could not occur. So we must not think that the air itself is shaped by the voice sent out, or by things of that kind—for the air would fall far short of being affected that way by a voice—but that the blow that occurs in us when we utter a sound at once squeezes out certain particles that make up a breathlike current, and this produces in us the experience of hearing.

And we must also hold that smell, just like hearing, would never produce any experience unless certain particles were carried off from the object, of the right size to stimulate this sense organ, some of them in a disturbing and alien way, others in an undisturbing and congenial way.

Moreover, we must hold that atoms bring with them none of the qualities of visible things except shape, weight, and size, and whatever necessarily goes with shape. For every quality changes, but the atoms do not change at all, since when compounds dissolve something solid and indissoluble must remain, which will produce changes not into what is not, nor from what is not, but by rearrangement in many cases, and in some by additions and subtractions. Hence what is rearranged must be indestructible and not have the nature of what changes, but have its own masses and shapes; for these must remain.

For in things around us that change shape as parts are taken away, the shape is found to remain in them, while the qualities do not remain in the changing thing, as the shape is left, but vanish from the whole body. So these remaining features are enough to produce the differences between compounds, since something must remain and not be destroyed into what is not.

Nor, however, must we think that atoms come in every size, or the appearances will contradict us; but we must hold that there are some variations in size. For if this is added, what happens in our feelings and sensations will be better explained. X 56 But atoms of every size are of no use in explaining differences of quality, and besides, some atoms would have had to reach us that were visible. This is not observed to happen, nor can one conceive how an atom could become visible.

Besides this, we must not think that a limited body contains unlimited particles, or particles of any size whatever. So we must not only do away with division to infinity into ever smaller parts, so that we don’t make everything weak and, in our conceptions of composite things, find ourselves forced to grind what exists down and use it up into what is not; but we must also not think that in limited bodies one can pass on from part to part to infinity, even to smaller and smaller parts.

For once someone says that there are unlimited particles in something, or particles of any size whatever, it is impossible to conceive how this magnitude could still be limited. For clearly the unlimited particles are of some size; and whatever size they are, the magnitude too would be unlimited. And since what is limited has an extremity that can be distinguished, even if it cannot be observed by itself, one cannot help conceiving the next part after it to be of the same kind, and so, going forward from one part to the next, reaching the unlimited in thought in this way.

We must also understand that the minimum perceptible by sense is neither like what admits passage from part to part, nor wholly unlike it in every way. It has something in common with what admits such passage, but it has no distinction of parts. When, because of the resemblance given by this common feature, we think we will distinguish some part of it, one on this side and another on that, it must be something equal that strikes us. We observe these minima one after another, starting from the first, not in the same place and not touching part to part, but measuring out magnitudes by their own distinctive character: more of them for a larger magnitude, fewer for a smaller.

We must hold that the minimum in the atom also follows this analogy. Clearly it differs in smallness from the minimum observed by sense, but it follows the same analogy. Indeed, our very claim that the atom has size we made by analogy with things here, merely projecting something small a long way down. Further, we must think of the minimal and unmixed limits as supplying from themselves, as primary units, the measure for larger and smaller lengths, when reason contemplates invisible things. For what they have in common with things that do not admit passage from part to part is enough to establish this much; but they could not come together into a compound as though they had motion of their own.

Moreover, in the unlimited we must not predicate up or down as though of a highest or lowest point. We know, however, that what is above our heads, from wherever we stand, if extended to infinity, will never appear to us that way, nor will what is below the point conceived, extended to infinity, be at once up and down relative to the same thing; for that is impossible to think. So it is possible to take as one the motion conceived as upward to infinity, and as one the motion downward, even if what moves from us toward the places above our heads reaches the feet of those above us ten thousand times, or what moves downward from us reaches the heads of those below. For the whole motion in each direction is none the less conceived as opposite to the other, to infinity.

Moreover, the atoms must move at equal speed when they are carried through the void with nothing colliding with them. For heavy atoms will not travel faster than small and light ones, when nothing meets them; nor small ones faster than large, since every passage fits them, when nothing collides with the large ones either. Nor is upward or sideways motion due to collisions faster, nor downward motion due to their own weight. For as long as either kind of motion prevails, the atom will keep moving as fast as thought, until something collides with it, either from outside or from its own weight countering the force of what struck it.

Yet in compounds one atom will be carried faster than another, although the atoms are of equal speed, because the atoms in aggregates move toward one place in the smallest continuous time, though not toward one place in the times observable by reason; rather, they collide constantly, until the continuity of the motion comes within the reach of sensation. For the opinion we add about what is invisible—that the times observable by reason will also contain continuous motion—is not true in such cases. For everything observed, or grasped by the mind in an act of apprehension, is true.

Next, referring to the sensations and the feelings—for this is how the firmest conviction will be reached—we must see that the soul is a body made of fine parts, scattered through the whole aggregate, most like breath with some admixture of heat, in some respects resembling the one and in some the other. But there is also a third part, which far exceeds even these in the fineness of its parts, and because of this is all the more in sympathy with the rest of the aggregate as well. All this is shown by the soul’s powers, its feelings, its ease of movement, its thoughts, and the things whose loss means death. Moreover, we must hold that the soul contains the greatest share of the cause of sensation. X 64 Yet it would not have acquired this unless it were somehow enclosed by the rest of the aggregate.

So as long as the soul is present, it never lacks sensation, even if some other part has been lost. Even if parts of the soul perish too, when what encloses it is dissolved in whole or in part, if the soul survives, it will have sensation. But the rest of the aggregate, even if it survives in whole or in part, has no sensation once the soul has departed, however small the number of atoms that go to make up the nature of the soul. Moreover, when the whole aggregate is dissolved, the soul is scattered and no longer has the same powers, nor does it move, and so it has no sensation either.

For it is impossible to conceive of the soul having sensation when it is not in this structure and not using these motions, once what encloses and surrounds it is no longer such as it now is in, having these motions. [He says elsewhere that the soul is made of the smoothest and roundest atoms, quite different from those of fire; that part of it is irrational, and this is scattered through the rest of the body, while the rational part is in the chest, as is clear from fears and joy; that sleep occurs when the parts of the soul scattered through the whole compound are held in or dispersed, and then collide through their impacts; and that seed comes from the whole body.]

Further, we must also take this into account: in the most common use of the word, we call “incorporeal” what could be conceived by itself. But nothing incorporeal can be conceived by itself except the void. And the void can neither act nor be acted on; it only allows bodies to move through it. So those who say the soul is incorporeal are talking nonsense. If it were such, it could neither act nor be acted on at all; but as it is, both these properties are clearly seen to belong to the soul.

So if one refers all these reasonings about the soul to the feelings and sensations, remembering what was said at the beginning, one will see well enough that they are included in the outlines, so that from them the details can be worked out with certainty.

Moreover, shapes, colors, sizes, weights, and whatever else is predicated of a body as its attributes, whether of all bodies or of visible ones, and known through sensation itself: we must not think that these are natures existing by themselves, since that is impossible to conceive; X 69 nor that they do not exist at all; nor that they are some other incorporeal things present in the body in addition; nor that they are parts of it. Rather, we must think that the body as a whole has its own permanent nature from all of them—not as though it were put together from them, as when a larger aggregate is made up of particles, whether primary ones or magnitudes smaller than the particular whole, but only, as I say, as having its own permanent nature from all of them.

Moreover, bodies often have properties that do not go with them permanently, which are neither among invisible things nor incorporeal. So, using this term in its most common sense, we make clear that these accidents have neither the nature of the whole, which we take together as an aggregate and call body, nor the nature of the permanent attributes, without which a body cannot be conceived. Each of them could be named according to certain acts of apprehension, with the whole going along with it, X 71 but only at whatever times each is observed to be present, since accidents do not go with bodies permanently.

And we must consider this point carefully too. Time must not be investigated like the other things we investigate in a subject, by referring them to the preconceptions we see within ourselves. Rather, we must reason from the clear experience itself by which we speak of a long or short time, treating it as something intimately familiar. We must not substitute other expressions as better, but use the ones already in use for it; nor must we predicate anything else of it, as though it had the same substance as this distinctive feature—some people do this—but we must above all reckon only with what we connect this distinctive feature with and measure it by.note

In addition to what has been said, we must hold that the worlds, and every limited compound that closely resembles the things we see, have come into being from the unlimited, all of them separated off from their own whirls, larger and smaller; and that all are dissolved again, some faster, some more slowly, some suffering this from causes of one kind, others from causes of another. [So it is clear that he holds the worlds to be perishable, since their parts change. And elsewhere he says the earth rides on the air.]

Further, we must not think that the worlds necessarily have one shape … [But he himself says in book 12 of On Nature that they differ: some are spherical, others egg-shaped, others of other shapes; but they do not have every shape. Nor are they living creatures separated off from the unlimited.] For no one could demonstrate that a world of one kind might have included the kinds of seeds from which animals, plants, and all the other things we see are formed, while a world of another kind could not have. [And likewise that they could be nourished there. And we must think the same way about the earth.]note

We must also suppose that human nature was taught and compelled by circumstances themselves to do many things of all kinds, and that reasoning later refined what nature had handed on and made further discoveries, faster in some cases and more slowly in others, making greater advances in some periods and times and lesser ones in others.

Hence names too did not originally come into being by convention. Rather, human beings’ own natures, in each nation, having their own particular feelings and receiving their own particular impressions, sent out air shaped in a particular way by each of these feelings and impressions, according as the nations also differed by region. X 76 Later, particular expressions were established by common agreement in each nation, so that people’s meanings would be less ambiguous to one another and more concisely expressed. And those who knew of certain things not seen before, when introducing them, handed on certain sounds for them; some were compelled to utter these sounds, while others chose them by reasoning and expressed things in that way, following the most prevalent cause.

Moreover, in the heavens, motions, solstices, eclipses, risings, settings, and the like must not be thought to happen because some being serves and arranges them, now or in the future, while also enjoying complete blessedness along with indestructibility. X 77 (For troubles and cares, anger and favor, do not go with blessedness; these arise from weakness, fear, and dependence on others.) Nor again must we think that the heavenly bodies, which are fire massed together, possess blessedness and take on these motions at will. Rather, we must preserve their full majesty in all the terms applied to such conceptions, so that no opinions contrary to that majesty arise from them. Otherwise, the contradiction itself will produce the greatest disturbance in our souls.

Moreover, we must hold that it is the task of the study of nature to work out precisely the cause of the most important things, and that blessedness depends on this, and on knowing what the natures are that we observe in the heavens, and whatever else contributes to precise knowledge on this point.

Further, in such matters there is no question of several explanations, or of the possibility that things might be otherwise. It is simply that nothing suggesting conflict or disturbance can belong to an indestructible and blessed nature. And that this is simply so, the mind can grasp.

But what falls within the inquiry into settings and risings, solstices and eclipses, and whatever is akin to these, contributes nothing further to blessedness through the knowledge of it. People who know these things but don’t know what the natures are, or what the most important causes are, have just as many fears as if they knew nothing of them—perhaps even more, when the amazement produced by this additional knowledge can find no release in an ordered understanding of the most important matters.

So even if we find several causes of solstices, settings, risings, eclipses, and things of that sort, as was also the case with particular events, X 80 we must not think that our treatment of them has failed to reach the precision needed for our tranquility and blessedness. So, observing in how many ways a similar thing happens here with us, we must explain the causes of celestial phenomena and of everything not evident. We must disdain those who recognize neither what exists or happens in one way nor what happens in several ways, who overlook the appearance produced by distance, and who, further, do not know in what cases one cannot be free from disturbance, and in what cases one can be free from it just the same. If, then, we think a thing may happen in some particular way, and recognize the very fact that it may happen in several ways, we will be as free from disturbance as if we knew that it happens in this particular way.note

On top of all this, we must understand that the chief disturbance in human souls arises from believing that the heavenly bodies are blessed and indestructible and yet have wishes, actions, and motives at odds with this; from always expecting or suspecting something eternally terrible, as in the myths, or even fearing the absence of sensation in death, as though it concerned them; and from suffering all this not through opinions but through some irrational state of mind, so that, setting no limit to what is terrible, they are as disturbed as someone who holds these opinions at random, or even more. X 82 But tranquility is to be released from all these things and to keep in continual memory the general and most important points.

So we must pay attention to our present feelings and sensations—to those shared by all for what is shared, to our own for what is particular to us—and to all the clear evidence present according to each of the criteria. For if we pay attention to these, we will correctly explain the source of our disturbance and fear, and free ourselves from it, by explaining the causes of celestial phenomena and of the other things that keep happening, which frighten everyone else to the extreme.

These, Herodotus, are the most important points about the nature of the universe, set out for you in summary. X 83 So if this account is mastered and held with precision, I think that a person, even without going on to all the detailed points, will gain a strength beyond compare with the rest of humanity. For he will make clear on his own many of the details worked out in our whole system, and these very points, stored in memory, will help him constantly.

For they are such that even those already working out the details well enough, or even completely, can carry out most of their surveys of the whole of nature by analyzing them into apprehensions of this kind; while those who are not fully accomplished can use them, and in a way that needs no words, run through the most important points as fast as thought, for the sake of calm.

Epicurus to Pythocles, greetings.note

Cleon brought me a letter from you, in which you kept up your kindness toward me, in a way worthy of my care for you, and tried, not unconvincingly, to recall the reasonings that make for a blessed life. You asked me to send you a brief, easily grasped account of celestial phenomena, so that you could remember it easily; for what I have written elsewhere, you say, is hard to remember, even though, as you told me, you carry it about with you constantly. I was glad to receive your request and was filled with pleasant hopes. X 85 So, having written everything else, I am completing what you asked for: reasonings that will be useful to many others as well, especially to those who have only recently tasted the genuine study of nature, and to those caught up in business more demanding than the ordinary round.

First, then, we must not think that knowledge of celestial phenomena, whether discussed in connection with other things or on its own, has any other goal than tranquility and firm conviction, just as with everything else. X 86 We must not force the impossible, nor keep our theory alike in every respect to our discussions of ways of life or to our solutions of the other problems in physics—for example, that the universe is bodies and intangible nature, or that the elements are atoms, and all such things as have only one explanation consistent with the appearances. This is not so with celestial phenomena: they admit of several causes for their coming into being, and of several accounts of their nature, consistent with the sensations.

For we must not study nature by empty axioms and legislation, but as the appearances call for. Our life has no need now of unreason and empty opinion, but of living without confusion. Everything goes on without upheaval when everything is explained in the manner of several causes, consistently with the appearances, as long as one duly accepts what is plausibly said about them. But when someone admits one explanation and rejects another equally consistent with the appearance, clearly he falls away from all study of nature and slides down into myth. Some of the appearances here with us, which are observed as they actually are, provide signs of what happens in the heavens; the appearances in the heavens do not, for these can come about in several ways.

A world is an enclosure of the sky that contains stars, earth, and all the things that appear, cut off from the unlimited, and ending [and terminating in a boundary either rare or dense, which when dissolved will throw everything in it into confusion] in a boundary that either revolves or is at rest, with a round, triangular, or any other outline whatever. For all of these are possible, since none of the appearances in this world contradicts them, as one cannot perceive where it ends.

That there are unlimited worlds of this kind can be grasped; and also that such a world can come into being both within a world and in an interworld, as we call the space between worlds, in a place with much void and not in a large space that is pure and empty, as some say. This happens when suitable seeds flow from one world or interworld, or from several, and gradually make additions, articulations, and shifts to another place, as it may chance, and receive waterings from suitable sources until the world is complete and stable, for as long as the foundations laid can take in what is added.

The sun, the moon, and the other stars did not come into being on their own and were later taken in by the world [along with all that it preserves]. Rather, they were formed at once and grew [and likewise earth and sea] by accretions and whirlings of certain fine-particled natures, either breathlike or fiery or both. This too is what sensation suggests.

The size of the sun and of the other stars, as far as we are concerned, is just as large as it appears. [He says this also in Book 11 of On Nature: “For if,” he says, “it had lost its size because of the distance, it would far more have lost its color; for no distance is more commensurate with this than that one.”] In itself, it is either larger than what we see, or a little smaller, or the same size. For this is also how fires here among us are perceived by sensation when viewed from a distance. And every objection on this point will be easily dissolved if one attends to the clear evidence, as we show in the books On Nature.

The turnings of the sun and moon may come about through the slant of the heaven, compelled in this way at set times; equally, through the counter-pressure of the air; or because the matter suited to them is always catching fire on one side and giving out on the other; or because a rotation of this kind was wound around these stars from the beginning, so that they move in a sort of spiral. All such explanations, and those akin to them, are at odds with none of the clear evidence, provided that in such details one always holds to what is possible and can bring each of them into agreement with the appearances, without fearing the servile contrivances of the astronomers.note

The waning of the moon and its waxing again could come about through the turning of this body, and equally through configurations of the air, and also through the interposition of other bodies—in fact in every way in which things seen here among us prompt us to give accounts of this kind—unless someone, being in love with the single explanation, idly rejects the others, not having considered what it is possible for a human being to observe and what it is not, and so longing to observe what cannot be observed. Again, the moon may have its light from itself, or it may have it from the sun. X 95 For here among us, too, we see many things that have light from themselves and many that have it from others.

Eclipses of the sun and moon may come about through extinguishing, just as we see this happen here among us; and also through the interposition of other things, either the earth or some other invisible body of this kind. And in this way one must consider together the explanations that fit with one another, and that it is not impossible for some of them to coincide at the same time. [In Book 12 of On Nature he says this, and further that the sun is eclipsed when the moon darkens it, and the moon by the earth’s shadow, but also by withdrawal. X 97 Diogenes the Epicurean says this too, in Book 1 of his Selections.]

Further, let the regularity of the orbits be understood in the same way as some ordinary things here among us happen regularly; and let the divine nature not be brought in for these things at all, but be kept free of any duty and in complete blessedness. For if this is not done, the whole explanation of the heavenly phenomena will be futile, as it has already been for some who did not take hold of a possible method but fell into futility by thinking that things happen in one way only and throwing out all the others that are possible, being carried off into the inconceivable and unable to consider together the appearances, which must be accepted as signs.

The lengths of nights and days vary both because the sun’s motions above the earth become fast and then slow again, as it crosses regions of varying length, and because it traverses some regions faster or more slowly—as we also see certain things do here among us, and it is in agreement with these that we must speak about the heavens. Those who adopt the one explanation are at war with the appearances and have lost sight of how far it is possible for a human being to observe.

Weather signs may come about through coincidences of the seasons, as with the animals we see here among us, and also through alterations and changes in the air. Neither of these conflicts with the appearances; X 99 but in which cases the cause is this one or that one, it is not possible to discern.note

Clouds may come about and take shape both through the compression of air by the pushing together of winds, and through the entanglement of atoms that grip one another and are suited to produce this result, and through a gathering of streams from the earth and from waters; and it is not impossible for such formations to be produced in several other ways too. Rain may then be produced from them, in some cases as they are squeezed, in others as they change; X 100 and also by streams moving through the air as they are carried off from suitable places, when a more violent downpour comes from certain accumulations suited to such discharges. Thunder may come about through wind rolling around in the hollows of the clouds, as happens in our own vessels; through the roar of fire filled with wind inside them; through ruptures and separations of clouds; and through the rubbing and breaking of clouds that have frozen solid like ice.

Cyclones may come about through a cloud being forced down into the regions below in the form of a column, pushed by a mass of wind and carried along by a great deal of wind, while the wind outside at the same time pushes the cloud sideways; through the wind circling round as some air presses in from above; and when a great stream of winds arises and cannot flow off sideways because of the packed air all around. X 105 When the cyclone descends as far as the land, whirlwinds arise, in whatever way their generation comes about through the motion of the wind; when it reaches the sea, waterspouts are produced.

Earthquakes may come about through wind being trapped in the earth, set alongside small masses of it and moving continuously, whenever it produces a shaking of the earth. The earth takes in this wind either from outside, or from ground collapsing inward into cavernous places in the earth and turning the enclosed air into wind. Earthquakes may also be produced by the very transmission of motion from the fall of many masses of ground, and by its being sent back again when it meets the denser parts of the earth. X 106 And these motions of the earth may come about in several other ways as well.

Winds happen to arise from time to time as some foreign matter keeps slipping in little by little, and through the gathering of an abundant mass of water; the remaining winds arise when even a little falls into the many hollows and spreads through them.

Hail is produced both by a stronger freezing—when certain windy particles gather round from all sides and then break apart—and by a more moderate freezing of certain watery particles, together with a meeting of windy ones, which at once presses them together and breaks them up, so that they condense as they freeze, both in parts and in masses. X 107 Their roundness can quite possibly come about as the edges melt away on all sides, and as particles—whether watery or windy—gather evenly round on all sides, part by part, as is said, during the formation.

Snow may be produced when fine water pours out of the clouds through pores of suitable size, as suitable clouds are violently squeezed by wind, and then this water freezes as it falls because of some strong cold in the regions below the clouds. And through freezing in clouds that have an even thinness, such a discharge might also come from the clouds as the watery particles lying alongside one another are pressed together; these, as if compacting, produce hail, which happens mostly in spring. X 108 And this mass of snow might also be thrown off through the rubbing of clouds that have frozen. Snow may be produced in other ways as well.

Dew is produced both by the coming together, out of the air, of particles of the kind that produce such moisture; and by the rising of particles from damp places or places that have water, where dew is most often produced, and then their coming together in the same place, producing moisture, and moving back down to the regions below—just as we see things of this kind produced in many cases here among us. X 109 And frost is produced in no different way from dew, when such particles undergo a certain kind of freezing because of some surrounding cold air.

Ice is produced both by the squeezing of the round-shaped particles out of the water and the pressing together of the jagged and acute-angled ones present in the water; and by the addition from outside of such particles, which, when driven together, have made the water freeze by squeezing out a certain quantity of the round ones.

The rainbow comes about when the sun shines on watery air; or through a particular blending of light and air that will produce the distinctive features of these colors, whether all together or one at a time; and as it shines back again from this, the neighboring parts of the air will take on the coloring we see, as the light shines on its parts. X 110 This appearance of roundness comes about because the distance is seen by our sight as equal on all sides; or because the atoms in the air, or those in the clouds carried off from the sun, are pressed together in such a way that this compound settles into a kind of curve.

A halo forms around the moon either when air is carried toward the moon from all sides and evenly holds back the streams carried off from it just far enough to set this cloudlike ring around it in a circle without dispersing it entirely; or when it holds back the air around the moon evenly on all sides so as to set a dense ring around it. X 111 This happens in certain parts, either because some stream from outside forces it, or because heat seizes on pores suitable for producing this effect.

Comets come about either when fire gathers in certain places in the heavens at certain intervals, when circumstances allow; or when the heaven above us, at intervals, takes on a special motion so that such stars appear; or when they themselves, at certain times, are set in motion by some circumstance, come into our regions, and become visible. Their disappearance comes about from the opposite causes. X 112 Some stars happen to revolve in place, not only because this part of the world stands still while the rest revolves around it, as some say, but also because a circular eddy of air surrounds it that prevents them from wandering as the others do; or else because there is no suitable matter for them beyond, but only in this place where they are seen to lie.note

So-called falling stars may be produced partly through the stars’ rubbing against one another, and through something falling out wherever the outburst of wind takes place, as we said in the case of lightning; X 115 also through the coming together of atoms that produce fire, when there is an affinity of material for producing this, and their movement wherever the impulse took them at the start of their coming together; and through the gathering of wind in certain misty densities, its kindling because of its rolling around, then its bursting through what surrounds it and being carried to whatever place the impulse of its motion takes it. And there are countless other ways of producing this.

The weather signs given by certain animals come about by coincidence with the season. For the animals do not impose any necessity for a storm to be produced, nor does some divine nature sit watching for these animals to come out and then fulfill these signs. X 116 Such foolishness would not befall even an ordinary creature, if it were a little more refined, let alone one that possesses complete happiness.

Remember all these things, Pythocles. You will get far away from myth, and you will be able to see things of the same kind as these. Above all, devote yourself to the study of the first principles, of infinity, and of what is related to them, and further of the criteria and the feelings, and of the purpose for which we reason these things out. For when these above all are studied together, they will make it easy to see the causes of particular things. Those who have not wholeheartedly embraced these things could neither study these very things well nor attain the purpose for which they should be studied.

Epicurus to Menoeceus, greetings.note

Do and practice the things I kept urging on you, understanding them to be the elements of living well. First, believe that god is an indestructible and blessed living being, as the common idea of god has sketched it, and attach to him nothing foreign to his indestructibility or unsuited to his blessedness; but hold about him every belief that can preserve his blessedness together with his indestructibility. For gods do exist: our knowledge of them is clear. But they are not such as most people believe them to be, for most people do not keep them consistent with the way they conceive them. The impious person is not the one who does away with the gods of the many, but the one who attaches the opinions of the many to the gods.

For if he says this with conviction, why doesn’t he depart from life? That option is ready at hand for him, if he had firmly decided on it. But if he says it in mockery, he is trifling in matters that don’t allow it.

We must also remember that the future is neither ours nor wholly not ours, so that we neither count on it as certain to come nor despair of it as certain not to come.

We must also consider that of desires some are natural, others empty; of the natural, some are necessary, others natural only; and of the necessary, some are necessary for happiness, some for the body’s freedom from trouble, some for life itself. X 128 An unerring grasp of these things knows how to refer every choice and avoidance to the health of the body and the tranquility of the soul, since this is the goal of the blessed life. For the sake of this we do everything: so that we may be neither in pain nor afraid. Once this is achieved for us, the whole storm of the soul is stilled, since the living creature has no need to go off in search of something it lacks, or to seek anything else by which the good of soul and body will be made complete.

For whom do you consider better than the person who holds reverent beliefs about the gods; who is always fearless about death; who has reasoned out the goal of nature; who understands that the limit of good things is easy to reach and easy to obtain, while the limit of bad things involves either brief duration or brief pain; who laughs at fate, which some introduce as the mistress of all things, and says instead that some things happen by necessity, others by chance, and others through our own agency—because he sees that necessity is answerable to no one, that chance is unstable, and that what is up to us has no master, so that blame and its opposite naturally attach to it X 134 (for it would be better to follow the myth about the gods than to be a slave to the fate of the natural philosophers:

Practice these things, then, and what is akin to them, day and night, by yourself and with someone like you, and you will never be disturbed, waking or dreaming, but will live like a god among human beings. For a human being who lives among immortal goods is not at all like a mortal creature.

The limit of the magnitude of pleasures is the removal of all pain. Wherever pleasure is present, for as long as it is present, there is no pain of body or distress of mind, or both together.

Pain does not last continuously in the flesh. At its most extreme it is present for the shortest time, and pain that merely outweighs pleasure in the flesh does not last many days. And long illnesses hold more pleasure in the flesh than pain.

It is not possible to live pleasantly without living wisely, honorably, and justly, nor wisely, honorably, and justly without living pleasantly. Whoever lacks what makes it possible to live wisely, honorably, and justly cannot live pleasantly.

Whatever means one can ever use to gain security from other people is a natural good [that is, rule and kingship].

Some have wanted to become famous and admired, thinking that in this way they would secure safety from other people. So if the life of such people is safe, they have obtained the natural good; but if it is not safe, they do not have what they originally reached out for in keeping with what is natural.

No pleasure is bad in itself; but the things that produce certain pleasures bring troubles many times greater than the pleasures.

If every pleasure were concentrated, and lasted over time, and pervaded the whole aggregate or its most important parts, pleasures would never differ from one another.

If the things that produce the pleasures of the profligate dispelled the mind’s fears about the heavens, death, and pains, and also taught the limit of desires, we would never have any reason to find fault with them, since they would be filled with pleasures from every side and would have no pain or distress from any side—which is what is bad.

If we were not troubled at all by our worries about the heavens and about death—that it might somehow be something to us—and further by our failure to grasp the limits of pains and desires, we would have no need of the study of nature.

It was not possible to dispel fear about the most important matters without knowing the nature of the universe, while still suspecting something from the myths. So without the study of nature it was not possible to enjoy unmixed pleasures.

There was no use in securing safety from other people while things above remained objects of suspicion, and things beneath the earth, and in short things in the unlimited.

Although safety from other people comes to a certain extent through a power to repel them and through prosperity, the purest safety comes from a quiet life and withdrawal from the many.

Natural wealth is both limited and easy to obtain; the wealth of empty opinions runs off into infinity.

Fortune intrudes on the wise man only in small ways; the greatest and most important things reason has arranged, and throughout the whole span of life it arranges them and will arrange them.

The just man is the most free from disturbance; the unjust man is full of the greatest disturbance.

Pleasure in the flesh does not increase once the pain of want has been removed; it is only varied. And the limit of pleasure in the mind is produced by reasoning out these very things, and things of the same kind, that caused the mind its greatest fears.

Unlimited time contains the same amount of pleasure as limited time, if one measures its limits by reasoning.

The flesh takes the limits of pleasure to be unlimited, and only unlimited time could provide it. But the mind, having reasoned out the goal and limit of the flesh and dispelled the fears about eternity, provides a complete life and has no further need of unlimited time. Yet it does not shun pleasure either; and even when circumstances are bringing about its departure from life, it does not end as though it fell short of the best life in any way.

Whoever has understood the limits of life knows how easy it is to obtain what removes the pain of want and what makes the whole of life complete; so he has no further need of things that involve struggle.

We must reason out the real goal and all the clear evidence to which we refer our opinions; otherwise everything will be full of confusion and disturbance.

If you fight against all your sensations, you will have nothing to refer to in judging even those of them you say are false.

If you reject any sensation outright, and do not distinguish between an opinion awaiting confirmation and what is already present in sensation, in feelings, and in every act of presentation by the mind, you will throw the rest of your sensations into confusion too with your empty opinion, and so you will reject the criterion altogether. And if, in your conceptions formed by opinion, you treat as certain both everything that awaits confirmation and what lacks confirmation, you will not escape error; for you will have kept every ambiguity in every judgment of what is correct or incorrect.

If you do not on every occasion refer each of your actions to the goal of nature, but turn aside short of it to something else when you avoid or pursue, your actions will not be consistent with your words.

Of the desires, those that do not lead to pain if they are not fulfilled are not necessary; the craving for them is easily dispelled whenever they seem hard to obtain or likely to cause harm.

The same conviction that has made us confident that nothing terrible lasts forever, or even for long, has also seen that, within these very limits, security is achieved above all through friendships.

Of the desires, some are natural and necessary; some are natural but not necessary; and some are neither natural nor necessary but arise from empty opinion. [Epicurus considers natural and necessary those that free us from pain, like drink when we are thirsty; natural but not necessary those that merely vary pleasure but do not remove pain, like expensive food; and neither natural nor necessary those like crowns and the setting up of statues.]

Among natural desires, those that do not lead to pain if they are not fulfilled, yet involve intense eagerness, arise from empty opinion; and it is not because of their own nature that they are not dispelled, but because of people’s empty opinions.

Natural justice is a pledge of mutual advantage, to keep people from harming one another or being harmed.

For those animals that were unable to make agreements not to harm one another or be harmed, nothing was just or unjust. The same goes for those peoples that were unable or unwilling to make agreements not to harm or be harmed.

Justice was not something in itself, but an agreement, made whenever people dealt with one another in any place of any size, not to harm or be harmed.

Injustice is not bad in itself, but in the fear that comes from suspecting one will not escape the notice of those appointed to punish such acts.

Someone who secretly violates any of the terms people have agreed on with one another, not to harm or be harmed, cannot be confident that he will escape notice, even if for now he escapes it ten thousand times. For until his death it is uncertain whether he will go on escaping it.

In general, justice is the same for all, since it was something advantageous in people’s dealings with one another; but in view of the particular features of a region and of any other causes, it does not follow that the same thing is just for all.

Among the things believed to be just, whatever is confirmed as advantageous in the needs of people’s dealings with one another has the character of justice, whether or not it turns out to be the same for all. But if someone makes a law and it does not turn out to serve the advantage of people’s dealings with one another, it no longer has the nature of justice. And even if what is advantageous in the way of justice changes, but for some time fits the preconception, it was no less just for that time, for those who do not confuse themselves with empty words but simply look at the facts.

Where, without any change in circumstances, the things believed to be just were shown in actual practice not to fit the preconception, they were not just. But where, after circumstances changed, the same established rules of justice were no longer advantageous, there they were just at the time when they were advantageous for fellow citizens’ dealings with one another, and afterward no longer just, when they were not advantageous.

The person who has best arranged things against the insecurity caused by outsiders has made kindred of what he could; what he could not, he has at least not made alien; and where he could not do even this, he has kept clear of it and shut out whatever it was advantageous to shut out.

Those who had the power to secure the greatest confidence from their neighbors also lived together most pleasantly, having the firmest assurance; and having enjoyed the fullest intimacy, they did not lament the early passing of one who died as though it called for pity.