Chapter 17.—That Even Varro Himself Pronounced His Own Opinions Regarding the Gods Ambiguous. And the same is true with respect to all the rest, as is true with respect to those things which I have mentioned for the sake of example.  They do not explain them, but rather involve them.  They rush hither and thither, to this side or to that, according as they are driven by the impulse of erratic opinion; so that even Varro himself has chosen rather to doubt concerning all things, than to affirm anything.  For, having written the first of the three last books concerning the certain gods, and having commenced in the second of these to speak of the uncertain gods, he says:  “I ought not to be censured for having stated in this book the doubtful opinions concerning the gods.  For he who, when he has read them, shall think that they both ought to be, and can be, conclusively judged of, will do so himself.  For my own part, I can be more easily led to doubt the things which I have written in the first book, than to attempt to reduce all the things I shall write in this one to any orderly system.”  Thus he makes uncertain not only that book concerning the uncertain gods, but also that other concerning the certain gods.  Moreover, in that third book concerning the select gods, after having exhibited by anticipation as much of the natural theology as he deemed necessary, and when about to commence to speak of the vanities and lying insanities of the civil theology, where he was not only without the guidance of the truth of things, but was also pressed by the authority of tradition, he says:  “I will write in this book concerning the public gods of the Roman people, to whom they have dedicated temples, and whom they have conspicuously distinguished by many adornments; but, as Xenophon of Colophon writes, I will state what I think, not what I am prepared to maintain:  it is for man to think those things, for God to know them.” It is not, then, an account of things comprehended and most certainly believed which he promised, when about to write those things which were instituted by men.  He only timidly promises an account of things which are but the subject of doubtful opinion.  Nor, indeed, was it possible for him to affirm with the same certainty that Janus was the world, and such like things; or to discover with the same certainty such things as how Jupiter was the son of Saturn, while Saturn was made subject to him as king:—he could, I say, neither affirm nor discover such things with the same certainty with which he knew such things as that the world existed, that the heavens and earth existed, the heavens bright with stars, and the earth fertile through seeds; or with the same perfect conviction with which he believed that this universal mass of nature is governed and administered by a certain invisible and mighty force.