This theory claimed to bring the ancient Hellenic beliefs into agreement with the cosmography of astronomers, but this cosmography itself undermined the foundations of the system, in so far as it refuted the hypothesis of a physical opposition between the two halves of the universe. It was observed that a single sky revolved about our earth; that the same atmosphere, composed of the same elements, enveloped it entirely; that every part of it was, in turn, equally in the light and in the shade. Therefore physical phenomena must be identical over the whole surface of our globe; the climate of the Antipodes must be like that of our lands; if the Antipodes were peopled, it was by races like those of men and the beasts. Their inhabitants therefore were not the dead but living beings. The marvels of the Fortunate Isles did not exist and there was no reason for regarding the lower rather than the upper part of the heavens as the vast reservoir of souls. The doctrine which placed the subterranean kingdom of Pluto and Proserpina on the other side of the earth and in the other celestial hemisphere, made a poor resistance to this criticism of the Alexandrian geographers. If it did not entirely disappear, if its transmission can be followed down to the end of antiquity and even to the Middle Ages, it never was so widespread nor so active as another doctrine claiming to reconcile the beliefs of the past with accepted science. * * * * * This bold doctrine transported the whole subterranean world above the earth’s surface. We shall see, in the next lecture, on celestial immortality (p. 96), that the Pythagoreans conceived the idea of placing the Elysian Fields in the moon, and that the Fortunate Isles were similarly explained by them as being the sun and the moon bathed by the fluid of the ether. The _Inferi_ were thus the lower space, that is, the space extending between the sphere of the moon, which was the limit of the world of the gods, and our globe, which was the centre of the cosmic system. In the _Inferi_ the souls which had to suffer the chastisement of their faults were kept prisoners; they could not win to the stars but wandered plaintively on the earth’s surface and especially about their own tombs, and then rose through the atmosphere in which, little by little, they were purified by the elements. Allegorical interpretations found a place for the infernal rivers in this new topography of the Beyond: Acheron was explained as being the air, the Pyriphlegethon as the zone of hail and fire, and the meanderings of the Styx became the circles of the universe. We shall have occasion to return to the passage of the soul through this aerial purgatory and its ascension to the Elysian Fields of the sky.[195]