Whilst I was yet speaking, Pharnaces interrupting my discourse said: See here again the usual stratagem of the Academy brought into play against us, which is to busy themselves at every turn in speaking against others, but never to afford an opportunity for reproving what they say themselves; so that those with whom they confer and dispute must always be respondents and defendants, and never plaintiffs or opponents. You shall not therefore bring me this day to give you an account of those things you charge upon the Stoics, till you have first rendered me a reason for your turning the world upside down. Then Lucius smiling said: This, good sir, I am well contented to do, provided only that you will not accuse us of impiety, as Cleanthes thought that the Greeks ought to have called Aristarchus the Samian into question and condemned him of blasphemy against the Gods, as shaking the very foundations of the world, because this man, endeavoring to save the appearances, supposed that the heavens remained immovable, and that the earth moved through an oblique circle, at the same time turning about its own axis. As for us therefore, we say nothing that we take from them. But how do they, my good friend, who suppose the moon to be earth, turn the world upside down more than you, who say that the earth remains here hanging in the air, being much greater than the moon, as the mathematicians measure their magnitude by the accidents of eclipses, and by the passages of the moon through the shadow of the earth, gathering thence how great a space it takes up? For the shadow of the earth is less than itself, by reason it is cast by a greater light. And that the end of this shadow upwards is slender and pointed, they say that Homer himself was not ignorant, but plainly expressed it when he called the night θοή (that is, acute) from the sharp-pointedness of the earth’s shadow. And yet the moon in her eclipses, being caught within this point of the shadow, can scarce get out of it by going forward thrice her own bigness in length. Consider then, how many times the earth must needs be greater than the moon, if it casts a shadow, the narrowest point of which is thrice as broad as the moon. But you are perhaps afraid lest the moon should fall, if it were acknowledged to be earth; but as for the earth, Aeschylus has secured you, when he says that Atlas Stands shouldering the pillar of the heaven and earth, A burden onerous. If then there runs under the moon only a light air, not firm enough to bear a solid burthen, whereas under the earth there are, as Pindar says, columns and pillars of adamant for its support, therefore Pharnaces himself is out of all dread of the earth’s falling, but he pities the Ethiopians and those of Taprobane, who lie directly under the course of the moon, fearing lest so ponderous a mass should tumble upon their heads. And yet the moon has, for an help to preserve her from falling, her motion and the impetuosity of her revolution; as stones, pebbles, and other weights, put into slings, are kept from dropping out, whilst they are swung round, by the swiftness of their motion. For every body is carried according to its natural motion, unless it be diverted by some other intervening cause. Wherefore the moon does not move according to the motion of her weight, her inclination being stopped and hindered by the violence of a circular revolution. And perhaps there would be more reason to wonder, if the moon continued always immovable in the same place, as does the earth. But now the moon has a great cause to keep herself from tending hither downwards; but for the earth, which has no other motion, it is probable that it has also no other cause of its settlement but its own weight. For the earth is heavier than the moon, not only because it is greater, but also because the moon is rendered lighter by the heat and inflammation that is in it. In brief, it appears by what you say, if it is true that the moon is fire, that it stands in need of earth or some other matter, which it may rest on and cleave to, for the maintaining and nourishing of its power. For it is not possible to imagine how a fire can be preserved without some combustible matter. And you yourselves say that the earth continues firm without any basis or pedestal to support it. Yes surely, said Pharnaces, being in its proper and natural place, the very middle and centre of the universe. For this it is to which all heavy and ponderous things do from every side naturally tend, incline, and aspire, and about which they cling and are counterpoised. But every superior region, though it may perhaps receive some earthly and weighty thing sent by violence up into it, immediately repels and casts it down again by force, or (to speak better) lets it follow its own proper inclination, by which it naturally tends downwards.