In the passage from Hyginus, _terra_ in the singular is the spherical earth occupying the centre of the sphere formed by the universe. The ocean is on the surface of this spherical earth, and it washes “the limits of the circle of lands”. For this reason the heavenly bodies “are [popularly] supposed to set in it.” Hyginus then turns to the dry land (_terras_), and describes the land surface “between the boundaries of the Arctic and torrid zones” as divided into three parts, Europe, Asia, and Africa. In Isidore _terra_ means in the first instance, dry land, in the second—if he realized the meaning of Hyginus—the sphere; in the third, the dry land; in the fourth, the sphere. There is no evidence that Isidore was conscious of having made these transitions. He entirely omits the sentence in which Hyginus passes from the subject of the spherical earth to that of the lands. It is clear that Isidore has fallen into the same confusion here as in the passage quoted on p. 51; he uses the terminology of the spherical earth, while having no conception of anything but the flat earth.[367] The difficulty offered by the word _sphera_ in the passage quoted above from Isidore, is not insuperable, since it is clear from the following passage that he was not very definite in his notion of what a sphere was. A sphere and a circle apparently meant about the same thing to him. [367] For passages illustrating Isidore’s cosmology, see _Etym._, 2, 24, 2; 3, 52, 1; 3, 47; 9, 2, 133; 11, 3, 24; 13, 1, 1. See also pp. 50–58 and notes. Cujus perfectionem spherae vel circuli multis argumentationibus tractans, rationabile Plato Fabricatoris mundi insinuat opus. Primo, quod ex una linea constat. Secundo, quod sine initio est et sine fine. Tertio, quod a puncto efficitur. Denuo, quod motum ex se habeat. Deinde quod careat indicio angulorum, et quod in se ceteras figuras omnes includat, et quod motum inerrabilem habeat, siquidem sex alii motus errabiles sunt, ante, a tergo, dextra, laevaque, sursum, deorsum. Postremo, et quod necessitate efficiatur, ut haec linea ultra circulum duci non possit. D. N. R., 12, 5. APPENDIX II SUBDIVISIONS OF PHILOSOPHY Philosophy was regarded by Isidore as a comprehensive term embracing all knowledge. He gives its subdivisions as follows: I. Arithmetica Naturalis Geometria or Musica Physica Astronomia Prudentia Moralis Justitia Philosophia or Fortitudo Ethica Temperantia Rationalis Dialectica or Logica Logica