The Nature of the Universe (Physics)
  -So we begin the study of Nature with this first observation: nothing is created out of that which does not exist. For if it were, everything would be created out of everything, with no need of seeds.  ((Epicurus' Letter to Herodotus))
  -But if this were so, men might be born out of the sea, fish out of the earth, and birds might burst forth out of the sky. Nor would the same fruits keep constant to trees, but would change; any tree might bear any fruit. ((Lucretius Book I))
  -But in fact we see that this is not so, because things are all produced from fixed seeds, each thing is born and goes forth into the borders of light composed of its own combination of elements; and for this reason all things cannot be gotten out of all things, because in particular things resides a distinct power. ((Lucretius Book I))
  -And from these distinct powers of particular elements, all kinds of herbage and corn and joyous trees even now spring in plenty out of the earth, each after its own fashion, and all preserve their distinctive differences according to a fixed law of nature. ((Lucretius Book V))
  -Again, why do we see the rose put forth in spring, corn in the season of heat, vines yielding at the call of autumn? If things came from nothing, they would rise up suddenly at uncertain periods and unsuitable times of the year, nor would time be required for the growth of things if they could increase out of nothing. ((Lucretius Book I))
  -Little babies would at once grow into men, and trees in a moment would rise and spring out of the ground. But we see that none of these events ever come to pass, since all things grow step by step as is natural. ((Lucretius Book I))
  -We must also observe that in course of time Nature dissolves every thing back into its first bodies, but does not totally annihilate anything. ((Lucretius Book I))
  -For if that which disappears were totally destroyed, all things would have long since perished, since that into which they were dissolved would not exist. ((Epicurus' Letter to Herodotus))
  -If the elements were themselves mortal, things in a moment would be snatched away to destruction from before our eyes; since no force would be needed to produce disruption among its parts and undo their fastenings. ((Lucretius Book I))
  -But in fact, all things consist of an imperishable elements, and nature allows the destruction of nothing to be seen until a force is encountered sufficient to dash things to pieces by a blow, or to pierce through the void places within them and break them up. ((Lucretius Book I))
  -If time, through age, utterly destroys all things, eating up all their matter, out of what does Venus bring back into the light of life the race of living things, each after its kind? Out of what does Earth give them nourishment, furnishing each one with food? ((Lucretius Book I))
  -Out of what do the fountains and rivers keep full the sea? Out of what does ether feed the stars? For infinite time gone by would have eaten up all things if they were formed of mortal bodies. ((Lucretius Book I))
  -Now if those bodies of which the sum of things is composed have existed for an infinite period of time, they no doubt have imperishable bodies, and cannot therefore return to nothing. ((Epicurus' Letter to Herodotus))
  -And so in its elements the universe always was such as it is now, and always will be the same. There is nothing new into which the universe can change, for there is nothing new outside the universe which could come into it and bring about change. ((Epicurus' Letter to Herodotus))
  -It is also true that everything in the universe is composed of bodies and space. As to bodies, the sense experience of all men perceives their existence. As to imperceptible space, we must reason from that to which the senses do testify. ((Epicurus' Letter to Herodotus))
  -And if that which we call space did not exist, bodies would have nowhere to be, and nothing through which to move. But we see that bodies do exist, and that they do move, so we know that space exists. ((Epicurus' Letter to Herodotus))
  -Besides bodies and space, nothing can even be thought of, either by conception or by analogy, so nothing can exist other than those things which are properties or qualities of bodies and space. ((Epicurus' Letter to Herodotus))
  -A property of a thing is that which can in no case be separated without utter destruction accompanying the severance, such as the weight of a stone, the heat of fire, or the fluidity of water. ((Lucretius Book I))
  -A quality of a thing is a relationship such as slavery or liberty, poverty or riches, and war or peace - which may come and go while the nature of the thing remains unharmed. ((Lucretius Book I))
  -Besides properties and qualities of bodies and space, no third nature can be considered to exist, neither can any third nature be perceived by our senses or grasped by the reasoning mind. ((Lucretius Book I))
  -But some men say that there exist, in another reality, a third nature which they call patterns, from which all things have been constructed by a divine creator. ((Plato Timaeus 29))
  -But no third nature can exist, only combinations of bodies and space. Such things as "Helen taken by Paris," or "Troy subdued in war," are not patterns which exist forever, but events in the lives of those who lived long ago, and these have now been irrevocably swept away by time.  ((Lucretius Book I)) 
  -As we turn our attention to the sum total of all the bodies and space that exist, we conclude that the universe as a whole is boundless. ((Epicurus' Letter to Herodotus))
  -For that which is bounded has an extreme point, and the extreme point is seen against something else. So because the universe as a whole has no extreme point, it has no limit, and as it has no limit, it must be boundless. ((Epicurus' Letter to Herodotus))
  -And in this boundless universe there are limitless numbers of worlds, some of which are like our own, and among such worlds there are living creatures and plants such as we see in this world. ((Epicurus' Letter to Herodotus))
  -For in the sum of all that exists there is no one thing which is begotten by itself alone, sole instance of its kind, but a thing always belongs to some class of which there are many others. ((Lucretius Book I))
  -And if there is so great a store of seeds that the whole can never be counted, and if the same force and nature abide in them as we see here in our own world, then we must admit that in other parts of space there are other Earths, other kinds of wild beasts, and other races of men. ((Lucretius Book II))
  -And there are also "gods," and the knowledge of them is manifest; but these "gods" are not such as the multitude believe, because men do not steadfastly maintain the notions they form respecting them. ((Epicurus' Letter to Menoeceus))
  -It is not the man who denies the gods worshiped by the multitude who is impious, but he who affirms of the gods what the multitude believes about them. For the beliefs of the multitude about the gods are not true preconceptions, but false assumptions. ((Epicurus' Letter to Menoeceus))
  -And among these false assumptions are the view that the gods cause evil to happen to the wicked and blessings to happen to the good, and that the gods favor and take pleasure in some men and reject others. ((Epicurus' Letter to Menoeceus))
  -So we must understand that when we see in the sky revolutions and eclipses, and risings and settings, these take place without the command of any being who enjoys immortality and perfect bliss. ((Epicurus' Letter to Herodotus))
  -For troubles and anxieties, and feelings of anger and partiality, do not accord with divinity, but imply weakness and fear and dependence upon one's neighbors. ((Epicurus' Letter to Herodotus))
  -Thus we must always hold fast to the majesty which attaches to such notions as bliss and immortality, lest we generate opinions inconsistent with this majesty. ((Epicurus' Letter to Herodotus))
  -For such error and inconsistency will produce the worst disturbances in our minds. Hence where we find phenomena invariably recurring, this recurrence must be ascribed to the original interception and conglomeration of atoms whereby the world was formed. ((Epicurus' Letter to Herodotus))
  -So let the regularity of the orbits be explained in the same way as ordinary incidents within our own experience. The divine nature must not on any account be used to explain this, but must be kept free from all tasks and in perfect bliss. ((Epicurus' Letter to Pythocles))
  -Unless this is done, the study of celestial phenomena will be in vain, as indeed it has been in vain for those who have fallen into the folly of supposing that these events can happen only in one way, and who reject all other possible explanations. ((Epicurus' Letter to Pythocles))
  -For in this way many men are carried into the realm of the unintelligible, and are unable to take a comprehensive view of those facts which are clues to the rest. ((Epicurus' Letter to Pythocles))
  -To assign a single cause for these effects which we see in the sky, when the facts suggest several causes, is madness and a strange inconsistency. ((Epicurus' Letter to Pythocles))
  -Yet this is done by some, who assign meaningless causes for the movement of stars whenever they persist in saddling the divinity with burdensome tasks. ((Epicurus' Letter to Pythocles))
  -To lay down as assured a single explanation of these phenomena is worthy only of those who seek to dazzle the multitude with marvels. ((Epicurus' Letter to Pythocles))
  -Such are those men who, straying widely from true reason, are famous for obscurity, more among the frivolous than among those earnest men who seek the truth. ((Epicurus' Letter to Pythocles))
  -For fools admire things which they perceive to be concealed under involved language, and they believe those things which tickle the ear and are varnished over with finely sounding phrases. ((Epicurus' Letter to Pythocles))
  -Some men who oppose us assert that Nature cannot without the providence of the gods vary the seasons of the year, bring forth crops, or do all those other things which Divine Pleasure, the Guide of Life, prompts men and other living things to do, escorting us in person, and enticing us by her guidance, so that neither mankind nor any race of living things may come to an end. ((Lucretius Book II))
  -Likewise there are those who seek to foretell the weather from the behavior of certain animals, which is mere coincidence. ((Epicurus' Letter to Pythocles))
  -For animals offer no necessary reason why a storm should be produced, and no divine being sits aloft, observing when these animals go out, and afterwards fulfilling the signs which they have given. ((Epicurus' Letter to Pythocles))
  -Such folly as this would not occur to the most ordinary being of the slightest enlightenment, much less to a divinity who enjoys perfect blissfulness. ((Epicurus' Letter to Pythocles))