To solve this great difficulty, or at least to mitigate the stupendous darkness in which it seems enveloped, various theories have been employed. The most celebrated of these are the following: 1. The hypothesis of the soul’s preëxistence; 2. The hypothesis of the Manicheans; and, 3. The hypothesis of optimism. It may not be improper to bestow a few brief remarks on these different schemes. Section I. The hypothesis of the soul’s preëxistence. This was a favourite opinion with many of the ancient philosophers. In the Phædon of Plato, Socrates is introduced as maintaining it; and he ascribes it to Orpheus as its original author. Leibnitz supposes that it was invented for the purpose of explaining the origin of evil;(140) but the truth seems to be, that it arose from the difficulty of conceiving how the soul could be created out of nothing, or out of a substance so different from itself as matter. The hypothesis in question was also maintained by many great philosophers, because they imagined that if the past eternity of the soul were denied, this would shake the philosophical proof of its future eternity.(141) There can be no doubt, however, that after the idea of the soul’s preëxistence had been conceived and entertained, it was very generally employed to account for the origin of evil. But it must be conceded that this hypothesis merely draws a veil over the great difficulty it was designed to solve. The difficulty arises, not from the circumstance that evil exists in the present state of our being, but from the fact that it is found to exist anywhere, or in any state, under the moral administration of a perfect God. It is as difficult to conceive why such a being should have permitted the soul to sin in a former state of existence, even if such a state were an established reality, as it is to account for its rise in the present world. To remove the difficulty out of sight, by transferring the origin of evil beyond the sphere of visible things, is a poor substitute for a solid and satisfactory solution of it. The great problem of the moral world is not to be illuminated by any such fictions of the imagination; and we had better let it alone altogether, if we have nothing more rational and solid to advance. Section II. The hypothesis of the Manicheans.