Finally, if the order of the elements is so disposed that, as Plato thinks, the two extremes, fire and earth, are united by the two means, air and water, and that the fire occupies the highest part of the sky, and the earth the lowest part, or as it were the foundation of the world, and that therefore earth cannot be in the heavens, how is fire in the earth? For, according to this reasoning, these two elements, earth and fire, ought to be so restricted to their own places, the highest and the lowest, that neither the lowest can rise to the place of the highest, nor the highest sink to that of the lowest. Thus, as they think that no particle of earth is or shall ever be in the sky so we ought to see no particle of fire on the earth. But the fact is that it exists to such an extent, not only on but even under the earth, that the tops of mountains vomit it forth; besides that we see it to exist on earth for human uses, and even to be produced from the earth, since it is kindled from wood and stones, which are without doubt earthly bodies. But that [upper] fire, they say, is tranquil, pure, harmless, eternal; but this [earthly] fire is turbid, smoky, corruptible, and corrupting. But it does not corrupt the mountains and caverns of the earth in which it rages continually. But grant that the earthly fire is so unlike the other as to suit its earthly position, why then do they object to our believing that the
nature of earthly bodies shall some day be made incorruptible and fit for the sky, even as now fire is corruptible and suited to the earth? They therefore adduce from their weights and order of the elements nothing from which they can prove that it is impossible for Almighty God to make our bodies such that they can dwell in the skies.