196 PHYSICAL SCIENCE IK THE MIDDLE AGES. 



We have some remarkable examples of this ; and a very notable one 

 is the celebrated question of the existence of Antipodes, or persons in- 

 habiting the opposite side of the globe of the earth, and consequently 

 having the soles of their feet directly opposed to ours. The doctrine 

 of the globular form of the earth results, as we have seen, by a geomet- 

 rical necessity, from a clear conception of the various points of knowl- 

 edge which we obtain, bearing upon that subject. This doctrine was 

 held distinctly by the Greeks ; it was adopted by all astronomers, 

 Arabian and European, who followed them ; and was, in fact, an in- 

 evitable part of every system of astronomy which gave a consistent 

 and intelligible representation of phenomena. But those who did not 

 call before their minds any distinct representation at all, and who re- 

 ferred the whole question to other relations than those of space, might 

 still deny this doctrine ; and they did so. The existence of inhabitants 

 on the opposite side of the terraqueous globe, was a fact of which ex- 

 perience alone could teach the truth or falsehood ; but the religious 

 relations, which extend alike to all mankind, were supposed to give 

 the Christian philosopher grounds for deciding against the possibility 

 of such a race of men. Lactantius, 10 in the fourth century, argues this 

 matter in a way very illustrative of that impatience of such specula- 

 tions, and consequent confusion of thought, which we have mentioned. 

 " Is it possible," he says, " that men can be so absurd as to believe 

 that the crops and trees on the other side of the earth hang down- 

 wards, and that men there have their feet higher than their heads ? 

 If you ask of them how they defend these monstrosities how things 

 do not fall away from the earth on that side they reply, that the 

 nature of things is. such that heavy bodies tend towards the centre, 

 like the spokes of a wheel, while light bodies, as clouds, smoke, fire, 

 tend from the centre towards the heavens on all sides. Now I am 

 really at a loss what to say of those who, when they have once gone 

 wrong, steadily persevere in their folly, and defend one absurd opinion 

 by another." It is obvious that so long as the writer refused to admit 

 into his thoughts the fundamental conception of their theory, he must 

 needs be at a loss what to say to their arguments without being on 

 that account in any degree convinced of their doctrines. 



In the sixth century, indeed, in the reign of Justinian, we find a 

 writer (Cosmas Indicopleustes") who does not rest in this obscurity of 



"> lust. 1. iii. 23. 



11 Montfaucon, Collectio J\~om Patrmn, t. ii. p. 113. Cosmas IndicopleustC* 

 Christianorum Opiuioues do ilundo, sire Topographia Christiana. 



