Plutarch De Defectu Oraculorum 24

[24] In the first place, then, said I, the considerations that prevent our making an infinite number of worlds do not preclude our making more than one. For it is possible for God and prophecy and Providence to exist in more worlds than one, and for the incidence of chance to be reduced to the very smallest limits, while the vast majority of things and those of the highest importance attain to genesis and transmutation in a quite orderly sequence, none of which things does infinity, by its nature, admit. Then again it is more consistent with reason that the world should not be the only-begotten of God and quite alone. For He, being consummately good, is lacking in none of the virtues, and least of all in those which concern justice and friendliness; for these are the fairest and are fitting for gods. Nor is it in the nature of God to possess anything to no purpose or for no use. Therefore there exist other gods and other worlds outside, in relation with which He exercises the social virtues. For not in relation with Himself nor with any part of Himself is there any exercise of justice or benevolence or kindness, but only in relation with others. Thus it is not likely that this world, friendless, neighbourless, and unvisited, swings back and forth in the infinite void, since we see that Nature includes individual things in classes and species, like seeds in pods and envelopes. For there is nothing in the whole list of existing things for which there is not some general designation, nor does anything that does not possess certain qualities, either in common with others or solely by itself, obtain such an appellation. Now the world is not spoken of as having qualities in common with others. It has its qualities, therefore, solely by itself, by virtue of the difference when it is compared with other things which are akin to it and similar in appearance, since it has been created with such qualities as it possesses. If in all creation such a thing as one man, one horse, one star, one god, one demigod does not exist, what is there to prevent creation from having, not one world, but more than one? For he who says that creation has but one land and one sea overlooks a matter which is perfectly plain, the doctrine of similar parts ¹ ; for we divide the earth into parts which bear similar names, and the sea likewise. A part of the world, however, is not a world, but something combined from the differing elements in Nature.

[24] First of all then, I say, the reasons which hinder us from asserting an infinite number of worlds do not hinder us from affirming that there are more than one; for as well in many worlds as in one there may be Providence and Divination, while Fortune intervenes only in the smallest things; but most part of the grand and principal things have and take their beginnings and changes by order, which could not be in an infinite number of worlds. And it is more conformable to reason to say that God made more than one world; for, being perfectly good, he wants no virtue, and least of all justice and friendship, for they do chiefly become the nature of the Gods. Now God hath nothing that is superfluous and useless; and therefore there must be other inferior Gods proceeding from him, and other worlds made by him, towards whom he must use these social virtues; for he cannot exercise those virtues of justice and benignity on himself or any part of himself, but on others. So that it is not likely this world should float and wander about, without either friend, neighbor, or any sort of communication, in an infinite vacuum. For we see Nature includes all single things in genera and species, like as in vessels or in husks of seeds; for there is nothing to be found in Nature—and nothing can have a common notion or appellation—which is not qualified both in common and in particular. Now the world is not said to be such in common, but in particular, for its quality is derived from its being an harmonious whole made up of different parts. But yet, there being no such thing in Nature as one man alone, one horse, one star, one God, one Daemon, why may we not believe that there is not in Nature one only world and no more, but several? And if any one shall object against me that this world hath likewise but one earth and one sea, I can answer him, he is much deceived by not understanding the evidence afforded by like parts. For we divide the earth into similar parts of the same denomination; for all the parts of the earth are earth, and so of the sea; but no part of the world is still the world, it being composed of divers and different natures.