Those who opposed Plato's theory of ideas said that he realized abstractions, or personified ideas; but no one, as I think, perceived the natural process which led him to do so, nor explained the faculty by which he was necessarily influenced. Plato's theory was only an ultimate phase of the evolution of the vague and primitive animation of the world, which had passed through fetishism, polytheism, and the worship of the elements of nature, and had reached the entification and subjectivity of ideas, which was also attained by natural science, after passing through its mythical envelopment. We have noted the causes, which in the case of the earlier philosophers happened to be objective, while they were in Plato's case subjective, owing to the character and temperament of his mind; both conduced to the development and æsthetic splendour of this teaching among the Greeks. The teaching of Plato, which had more or less influence on all the earlier civilized peoples, of his own and subsequent times, and which was also involved in the mythical representations of later savages, assumed an aspect which varied with the special history, the ethnic temperament, the geographical and extrinsic conditions of different peoples; but considered in itself, it is always the same, and is the necessary result of the evolution of myth and of thought. Since the evolution of myth leads to the gradual genesis of science, which becomes more rational as myth is transformed from the material to the ideal, ideas are substituted for myths, and laws, as Vico well observes, for the canons of poetry.
This noble and more rational theory of eternal and causative Ideas resembles anthropomorphic polytheism in concentrating into one supreme Idea the intellectual Zeus, the Being of beings, according to another mythical and scientific representation by Aristotle, and it was afterwards combined with the Semitic idea of the Absolute. This was fused with the Logos, the Platonic demiurgos of Messianic ideas, and afterwards produced the universal philosophy and religion of Catholicism, which dominated and still dominates over thought with vigorous tenacity, and extends into all the civilized world inhabited by European races. We do not only trace the same thought, modified, classified, and perfected in the Fourth Gospel, in the Councils, the Fathers, and the schoolmen, but also in independent philosophies. In our own time it has assumed new forms, derived from the rapid progress made in cosmic and experimental sciences, even in those which are apparently the most rationalizing. It is manifest in Hegel, Fichte, and Schelling, nor is it difficult to trace it in the latest and artificial theories of the schools of Schopenhauer and Hartmann. In all these cases the entification of logical conceptions is evident; in all there is an arbitrary personification of a conception or of a fundamental Idea.