It may be that certain of the pagan gods are nothing but the stars which bear their names. For example, there is one star called Mercury and another called Mars. There is another star, though, which they call Jupiter; yet, for them, Jupiter is the whole universe. There is one they call Saturn; yet to their god Saturn they attribute the not inconsiderable substance of all things that can grow. Then, there is the brightest of all stars, which they call Venus; yet, for some of them, Venus is also the moon. As to the bright star, Juno and Venus have rival claims—as they had for the golden apple. Some say Lucifer belongs to Venus; some, to Juno—and, as always, Venus wins. In fact, practically no one can be found to oppose the majority who attribute this star to Venus. But, the best joke is when they admit that the star of Jupiter, the ‘King of the universe’ is far outshone by the star of Venus. Surely, Jupiter should have been brighter than the rest, in proportion to his power. Their answer is that it merely seems this way, because Jupiter, which seems less bright, is higher up and farther removed from the earth.
Very well, but, if a higher place is the reward of greater dignity, why is Saturn even higher than Jupiter? Or was it that the echo of the fable which makes Jupiter king was too faint to reach the stars? Or, perhaps, Saturn was allowed to make up in the stars what he lost in Crete and on the Capitol! Another question. Why did Janus get no star? It is of no use to say: He is the universe and all stars are in him. Jupiter is also the universe, yet he has his star. Maybe Janus made the best of a bad job, making up by a multitude of faces on earth for the one star he lost in the heavens!
Further, it is merely because of the stars that Mercury and Mars are parts of the cosmos and so can be reckoned as gods; for, certainly, speech and war are not parts of the universe, but only human acts. But, Aries, Taurus, Cancer, Scorpion and the rest of the signs of the zodiac, which are not merely single stars but whole constellations, are said to be higher up in heaven where the steadier motion keeps the stars from wandering as the planets do. Why, then, do they have no altars, no sacrifices, no temples in their honor? The pagans never reckoned them as gods, not even as plebeian gods, so to speak, let alone as select divinities.
According to the pagan conception, Apollo was a seer and a doctor, but, in order to assign him a part of the universe, they called him the Sun, as they called his sister Diana the Moon. Diana was likewise given charge of roads and hence was considered a virgin, on the ground that a road [via] produces nothing. Both Apollo and Diana have arrows to symbolize the fact that the rays of both the sun and moon reach as far as the earth. Vulcan is the fire of the universe as Neptune is water. Dispater or Orcus is the earth or lowest part of the universe. Bacchus and Ceres are in charge of things that grow, the former being assigned either to male seed or else to the fluid element of seeds, the latter to the female or dry element. Of course, this is all related to the universe or to Jupiter, who is called both ‘Father and Mother’ as being responsible for both the giving forth and getting back of all seed. However, they also regard Ceres as the Great Mother, which for them is the same as the earth; the earth, in turn, is also Juno. Hence, to Juno are assigned secondary causes, even though Jupiter is addressed as ‘Father and Mother of the gods’ because, in the pagan conception, he is the whole universe.
Minerva was given charge of human intellectual disciplines, but, when no star was available for her use, they called her the ether or, sometimes, the moon. Vesta they also regarded as one of the greatest of the goddesses in the belief that she, too, was the earth. Her special charge was the milder kind of fire which lightens the works of men, though not the violent kind that belongs to Vulcan.
It would thus appear that the pagans took all of the select divinities for the cosmos, seeing the whole in some and merely parts in others. Thus, Jupiter is the whole universe, while Genus, the Great Mother, Sol (or Apollo) and Luna (or Diana) were parts. Sometimes, many things were made into one god; at other times, many gods made up one reality. Jupiter is an example of one god being many things—for he is the whole cosmos or the sky alone, and he is considered and called a single star. In the same way, Juno is the mistress of all secondary causes, but she is also the air and the earth and (when she takes away the honor from Venus) a star. So, too, Minerva is the highest ether and also the moon, which is reckoned as being in the lowest reaches of the ether.
However, they make several gods of a single thing. Thus, both Janus and Jupiter are the cosmos; and Juno and the Great Mother and Ceres are the earth.
These are but a few specimens. But, all the rest of the mythology, too, is more confounded than expounded by the interpretations. Wherever the currents of meandering opinion carry the interpreters they swing back and forth and hither and thither. Even Varro himself preferred to doubt about everything than to affirm anything with certainty. Thus, having finished the book about the known gods, which was the first of his last three, he began the second, dealing with the unknown gods, by saying: ‘I hope I shall not be criticized for setting forth, in this book, doubtful opinions about the gods. Any of my readers who think they can, and should, make definite decisions are at liberty to make them. For myself, I could be more easily persuaded to cast doubt on what I decided in the first book than to attempt, in the book I am writing, a consistent synthesis.’ Thus, he casts doubt, not only on the book about the unknown gods, but on the book about the ones that are certain.
In the third of these books which deals with the select gods, after a preface discussing certain important aspects of natural theology, he turns to the fanciful inanities and absurdities of the so-called political theology. Having no certain truth to guide him and hemmed in by the authority of tradition, he wrote as follows: ‘I am to speak in this book of the official gods of the Roman people, gods for whom temples have been dedicated and whose many ornaments have made them famous, but I shall take my cue from a remark of Xenophanes of Colophon: I shall set forth what seems, not what I can prove, to be true. In a field where only God has knowledge, man must be content with opinions.’
Writing, as he was, about human inventions, all he could do was to make a hesitating promise to deal with matters neither fully understood nor firmly believed, and subject to the fluctuations of doubts and opinions. He could know that the universe existed and was made up of the heavens and the earth, that the heavens were bright with stars and the earth rich in seeds, and so one; and he could believe with firm conviction that some omnipotent and invisible force ruled and arranged the immense structure of nature; but neither science nor faith could assure him that Janus was the cosmos, or explain why Saturn should be the father of Jupiter and yet have become his subject, and other things like that.
Augustine of Hippo, The City of God, Books I–VII