Plato held the eternity of matter. The material of which the world was formed was originally a shapeless mass existing from eternity. It was arranged in perfect and beautiful forms by God. Plato comments on the nature of the soul, the soul of the world, the origin of evil, and the four original elements of all created, corporeal things. But the soul is both created and uncreated. The subject is illustrated by geometry and the doctrine of ratios, and by the musical scale. The divisible and the indivisible are the Other and the Same. The opinion of those philosophers who make the soul a compound of both refuted. Two discordant principles rule the world: Fate or Necessity, and Intelligence or Wisdom. The soul is not altogether the workmanship of the Deity: Illustrations from geometry, the planetary system, and the science of music. The soul derives its beginning neither from time nor is the product of generation, but it is endowed with several faculties and virtues.