In this book Cicero summarizes the arguments for and against the existence of “gods,” and also addresses the nature of those gods and what influence they have, if any, on humanity. Velleius presents the Epicurean position, Lucilius Balbus presents the Stoic position, and Cotta presents the Academic Skeptic position. Cicero does not participate directly in the debate, but at the end he takes the position that he thinks the Stoic argument is the best. This is despite the fact that Cicero generally considers himself to be of the same school as Cotta. Velleius maintains the Epicurean position throughout, but mentions at the end that as between the Academic Skeptic arguments with the Stoics, he considers the Academic Skeptic side closer to his own.

1. Introduction by Cicero, with discussion of the reason for writing this and the importance of the subject.
2. Cotta asks Velleius to present his views first. Cicero remarks that Velleius sounds confident, in typical Epicurean fashion, as if he had just come down from the presence of the gods in the intermundia.
3. Velleius presents the Epicurean argument against other schools
   1. There is no sensory evidence that supports the tales of the supernatural gods told by other schools.
      1. “For with what eyes of the mind was your Plato able to see that workhouse of such stupendous toil, in which he makes the world to be modeled and built by God?
   2. The other schools can give no explanation of how the universe was created.
      1. “What materials, what tools, what bars, what machines, what servants, were employed in so vast a work?
      2. How could the air, fire, water, and earth pay obedience and submit to the will of the architect?
      3. From whence arose those five forms, of which the rest were composed, so aptly contributing to frame the mind and produce the senses?
      4. The arguments that the other schools make on this point are mere wishful thinking.
   3. A created world cannot eternal.
      1. “But, what is more remarkable, he gives us a world which has been not only created, but, if I may so say, in a manner formed with hands, and yet he says it is eternal. Do you conceive him to have the least skill in natural philosophy who is capable of thinking anything to be everlasting that had a beginning? For what can possibly ever have been put together which cannot be dissolved again? Or what is there that had a beginning which will not have an end?”
   4. The Stoic and Aristotelian “First Cause” does not answer the problem of how the universe was created.
      1. If you allege like Aristotle or the Stoics that there was some original first cause, rather than a supernatural god like Plato asserts, how did this “first cause” create the universe we see, and why is the world mortal, as we see it to be, rather than immortal like Plato's god is asserted to have made it?
      2. If the Stoic Providence is the same as Plato’s God, who were the assistants, what were the engines, what was the plan and preparation of the whole work? If it is not the same, then why did she make the world mortal, and not everlasting, like Plato’s God?
   5. It makes no sense to say that world-building gods woke up to make the universe, because what were they doing for an eternity of time before that?
      1. “But I would demand of you both, why these world-builders started up so suddenly, and lay dormant for so many ages? For we are not to conclude that, if there was no world, there were therefore no ages. I do not now speak of such ages as are finished by a certain number of days and nights in annual courses; for I acknowledge that those could not be without the revolution of the world; but there was a certain eternity from infinite time, not measured by any circumscription of seasons; but how that was in space we cannot understand, because we cannot possibly have even the slightest idea of time before time was. I desire, therefore, to know, Balbus, why this Providence of yours was idle for such an immense space of time? Did she avoid labor? But that could have no effect on the Deity; nor could there be any labor, since all nature, air, fire, earth, and water would obey the divine essence. What was it that incited the Deity to act the part of an ædile, to illuminate and decorate the world? If it was in order that God might be the better accommodated in his habitation, then he must have been dwelling an infinite length of time before in darkness as in a dungeon. But do we imagine that he was afterward delighted with that variety with which we see the heaven and earth adorned? What entertainment could that be to the Deity? If it was any, he would not have been without it so long.
   6. It makes no sense to say that the gods created the universe for humans. Who benefited from the creation of the universe? If the wise, that's a very small number. If fools, why seek to benefit them?
      1. Or were these things made, as you almost assert, by God for the sake of men? Was it for the wise? If so, then this great design was adopted for the sake of a very small number. Or for the sake of fools? First of all, there was no reason why God should consult the advantage of the wicked; and, further, what could be his object in doing so, since all fools are, without doubt, the most miserable of men, chiefly because they are fools? For what can we pronounce more deplorable than folly? Besides, there are many inconveniences in life which the wise can learn to think lightly of by dwelling rather on the advantages which they receive; but which fools are unable to avoid when they are coming, or to bear when they are come.
   7. A round ball hurtling through space cannot be a god.
      1. [X] They who affirm the world to be an animated and intelligent being have by no means discovered the nature of the mind, nor are able to conceive in what form that essence can exist; but of that I shall speak more hereafter. At present I must express my surprise at the weakness of those who endeavor to make it out to be not only animated and immortal, but likewise happy, and round, because Plato says that is the most beautiful form; whereas I think a cylinder, a square, a cone, or a pyramid more beautiful. But what life do they attribute to that round Deity? Truly it is a being whirled about with a celerity to which nothing can be even conceived by the imagination as equal; nor can I imagine how a settled mind and happy life can consist in such motion, the least degree of which would be troublesome to us. Why, therefore, should it not be considered troublesome also to the Deity? For the earth itself, as it is part of the world, is part also of the Deity. We see vast tracts of land barren and uninhabitable; some, because they are scorched by the too near approach of the sun; others, because they are bound up with frost and snow, through the great distance which the sun is from them. Therefore, if the world is a Deity, as these are parts of the world, some of the Deity’s limbs must be said to be scorched, and some frozen.
   8. It is wrong to allege that gods die, because who can imagine a god who is not deathless?
      1. It was Anaximander’s opinion that the Gods were born; that after a great length of time they died; and that they are innumerable worlds. But what conception can we possibly have of a Deity who is not eternal?
   9. It is wrong to allege that pure spirit can join with matter to produce the universe, because why would spirit mutilate itself by joining with mortal matter, if spirit were able to exist separately?
      1. Anaximenes, after him, taught that the air is God, and that he was generated, and that he is immense, infinite, and always in motion; as if air, which has no form, could possibly be God; for the Deity must necessarily be not only of some form or other, but of the most beautiful form. Besides, is not everything that had a beginning subject to mortality?
      2. [XI] Anaxagoras, who received his learning from Anaximenes, was the first who affirmed the system and disposition of all things to be contrived and perfected by the power and reason of an infinite mind; in which infinity he did not perceive that there could be no conjunction of sense and motion, nor any sense in the least degree, where nature herself could feel no impulse. If he would have this mind to be a sort of animal, then there must be some more internal principle from whence that animal should receive its appellation. But what can be more internal than the mind? Let it, therefore, be clothed with an external body. But this is not agreeable to his doctrine; but we are utterly unable to conceive how a pure simple mind can exist without any substance annexed to it.
      3. Alcmæon of Crotona, in attributing a divinity to the sun, the moon, and the rest of the stars, and also to the mind, did not perceive that he was ascribing immortality to mortal beings.
      4. Pythagoras, who supposed the Deity to be one soul, mixing with and pervading all nature, from which our souls are taken, did not consider that the Deity himself must, in consequence of this doctrine, be maimed and torn with the rending every human soul from it; nor that, when the human mind is afflicted (as is the case in many instances), that part of the Deity must likewise be afflicted, which cannot be. If the human mind were a Deity, how could it be ignorant of any thing? Besides, how could that Deity, if it is nothing but soul, be mixed with, or infused into, the world?
      5. XII. Empedocles, who erred in many things, is most grossly mistaken in his notion of the Gods. He lays down four natures84 as divine, from which he thinks that all things were made. Yet it is evident that they have a beginning, that they decay, and that they are void of all sense.
   10. Allegations that infinity is an attribute of divinity are also wrong.
       1. Then Xenophanes, who said that everything in the world which had any existence, with the addition of intellect, was God, is as liable to exception as the rest, especially in relation to the infinity of it, in which there can be nothing sentient, nothing composite.
       2. Parmenides formed a conceit to himself of something circular like a crown. (He names it Stephane.) It is an orb of constant light and heat around the heavens; this he calls God; in which there is no room to imagine any divine form or sense. And he uttered many other absurdities on the same subject; for he ascribed a divinity to war, to discord, to lust, and other passions of the same kind, which are destroyed by disease, or sleep, or oblivion, or age. The same honor he gives to the stars; but I shall forbear making any objections to his system here, having already done it in another place.
   11. It is useless to look to someone who says that he does not even know if gods exist.
       1. Protagoras did not seem to have any idea of the real nature of the Gods; for he acknowledged that he was altogether ignorant whether there are or are not any, or what they are.
   12. Those who say that gods are not everlasting destroy the true concept of divinity.
       1. What shall I say of Democritus, who classes our images of objects, and their orbs, in the number of the Gods; as he does that principle through which those images appear and have their influence? He deifies likewise our knowledge and understanding. Is he not involved in a very great error? And because nothing continues always in the same state, he denies that anything is everlasting, does he not thereby entirely destroy the Deity, and make it impossible to form any opinion of him?
   13. Those who attribute sense to formlessness are also wrong.
       1. Diogenes of Apollonia looks upon the air to be a Deity. But what sense can the air have? or what divine form can be attributed to it?
   14. The Academy, including Plato and Xenophon and Antisthenes held ideas of the gods that were inconsistent and unintelligible.
       1. It would be tedious to show the uncertainty of Plato’s opinion; for, in his Timæus, he denies the propriety of asserting that there is one great father or creator of the world; and, in his book of Laws, he thinks we ought not to make too strict an inquiry into the nature of the Deity. And as for his statement when he asserts that God is a being without any body—what the Greeks call ἀσώματος—it is certainly quite unintelligible how that theory can possibly be true; for such a God must then necessarily be destitute of sense, prudence, and pleasure; all which things are comprehended in our notion of the Gods. He likewise asserts in his Timæus, and in his Laws, that the world, the heavens, the stars, the mind, and those Gods which are delivered down to us from our ancestors, constitute the Deity. These opinions, taken separately, are apparently false; and, together, are directly inconsistent with each other.
       2. Xenophon has committed almost the same mistakes, but in fewer words. In those sayings which he has related of Socrates, he introduces him disputing the lawfulness of inquiring into the form of the Deity, and makes him assert the sun and the mind to be Deities: he represents him likewise as affirming the being of one God only, and at another time of many; which are errors of almost the same kind which I before took notice of in Plato.
       3. [XIII] Antisthenes, in his book called the Natural Philosopher, says that there are many national and one natural Deity; but by this saying he destroys the power and nature of the Gods. Speusippus is not much less in the wrong; who, following his uncle Plato, says that a certain incorporeal power governs everything; by which he endeavors to root out of our minds the knowledge of the Gods.
       4. From the same school of Plato, Heraclides of Pontus stuffed his books with puerile tales. Sometimes he thinks the world a Deity, at other times the mind. He attributes divinity likewise to the wandering stars. He deprives the Deity of sense, and makes his form mutable; and, in the same book again, he makes earth and heaven Deities.
   15. Aristotle and the Peripatetics, like Plato, were self-contradictory, and wrong in holding that a god has no body.
       1. Aristotle, in his third book of Philosophy, confounds many things together, as the rest have done; but he does not differ from his master Plato. At one time he attributes all divinity to the mind, at another he asserts that the world is God. Soon afterward he makes some other essence 222preside over the world, and gives it those faculties by which, with certain revolutions, he may govern and preserve the motion of it. Then he asserts the heat of the firmament to be God; not perceiving the firmament to be part of the world, which in another place he had described as God. How can that divine sense of the firmament be preserved in so rapid a motion? And where do the multitude of Gods dwell, if heaven itself is a Deity? But when this philosopher says that God is without a body, he makes him an irrational and insensible being. Besides, how can the world move itself, if it wants a body? Or how, if it is in perpetual self-motion, can it be easy and happy?
       2. Xenocrates, his fellow-pupil, does not appear much wiser on this head, for in his books concerning the nature of the Gods no divine form is described; but he says the number of them is eight. Five are moving planets;85 the sixth is contained in all the fixed stars; which, dispersed, are so many several members, but, considered together, are one single Deity; the seventh is the sun; and the eighth the moon. But in what sense they can possibly be happy is not easy to be understood.
       3. The unsteadiness of Theophrastus is equally intolerable. At one time he attributes a divine prerogative to the mind; at another, to the firmament; at another, to the stars and celestial constellations. Nor is his disciple Strato, who is called the naturalist, any more worthy to be regarded; for he thinks that the divine power is diffused through nature, which is the cause of birth, increase, and diminution, but that it has no sense nor form.
   16. The Stoics were wrong in holding that “the law of nature” is a divinity, and they are otherwise wrong in thinking that the sky is a god, or that rationality is a god, and in defending the ancient myths as allegories, and in holding that the form of a god is inconceivable, and other ways too.
       1. [XIV] Zeno (to come to your sect, Balbus) thinks the law of nature to be the divinity, and that it has the power to force us to what is right, and to restrain us from what is wrong. How this law can be an animated being I cannot conceive; but that God is so we would certainly maintain. The same person says, in another place, that the sky is God; but can we possibly conceive that God is a being insensible, deaf to our prayers, our wishes, and our vows, and wholly unconnected with us?
       2. In other books he thinks there is a certain rational essence pervading all nature, indued with divine efficacy. He attributes the same power to the stars, to the years, to the months, and to the seasons.
       3. In his interpretation of Hesiod’s Theogony, he entirely destroys the established notions of the Gods; for he excludes Jupiter, Juno, and Vesta, and those esteemed divine, from the number of them; but his doctrine is that these are names which by some kind of allusion are given to mute and inanimate beings.
       4. The sentiments of his disciple Aristo are not less erroneous. He thought it impossible to conceive the form of the Deity, and asserts that the Gods are destitute of sense; and he is entirely dubious whether the Deity is an animated being or not.
       5. Cleanthes, who next comes under my notice, a disciple of Zeno at the same time with Aristo, in one place says that the world is God; in another, he attributes divinity to the mind and spirit of universal nature; then he asserts that the most remote, the highest, the all-surrounding, the all-enclosing and embracing heat, which is called the sky, is most certainly the Deity. In the books he wrote against pleasure, in which he seems to be raving, he imagines the Gods to have a certain form and shape; then he ascribes all divinity to the stars; and, lastly, he thinks nothing more divine than reason. So that this God, whom we know mentally and in the speculations of our minds, from which traces we receive our impression, has at last actually no visible form at all.
       6. [XV] Persæus, another disciple of Zeno, says that they who have made discoveries advantageous to the life of man should be esteemed as Gods; and the very things, he says, which are healthful and beneficial have derived their names from those of the Gods; so that he thinks it not sufficient to call them the discoveries of Gods, but he urges that they themselves should be deemed divine. What can be more absurd than to ascribe divine honors to sordid and deformed things; or to place among the Gods men who are dead and mixed with the dust, to whose memory all the respect that could be paid would be but mourning for their loss?
       7. Chrysippus, who is looked upon as the most subtle interpreter of the dreams of the Stoics, has mustered up a numerous band of unknown Gods; and so unknown that we are not able to form any idea about them, though our mind seems capable of framing any image to itself in its thoughts. For he says that the divine power is placed in reason, and in the spirit and mind of universal nature; that the world, with a universal effusion of its spirit, is God; that the superior part of that spirit, which is the mind and reason, is the great principle of nature, containing and preserving the chain of all things; that the divinity is the power of fate, and the necessity of future events. He deifies fire also, and what I before called the ethereal spirit, and those elements which naturally proceed from it—water, earth, and air. He attributes divinity to the sun, moon, stars, and universal space, the grand container of all things, and to those men likewise who have obtained immortality. He maintains the sky to be what men call Jupiter; the air, which pervades the sea, to be Neptune; and the earth, Ceres. In like manner he goes through the names of the other Deities. He says that Jupiter is that immutable and eternal law which guides and directs us in our manners; and this he calls fatal necessity, the everlasting verity of future events. But none of these are of such a nature as to seem to carry any indication of divine virtue in them. These are the doctrines contained in his first book of the Nature of the Gods. In the second, he endeavors to accommodate the fables of Orpheus, Musæus, Hesiod, and Homer to what he has advanced in the first, in order that the most ancient poets, who never dreamed of these things, may seem to have been Stoics. Diogenes the Babylonian was a follower of the doctrine of Chrysippus; and in that book which he wrote, entitled “A Treatise concerning Minerva,” he separates the account of Jupiter’s bringing-forth, and the birth of that virgin, from the fabulous, and reduces it to a natural construction.