Passing by now the fact that Plato has furnished no satisfactory proof for the objective and independent reality of ideas, and that his theory is without vindication, we may affirm in the first place that it is wholly unfruitful, since it possesses no ground of explanation for being. The ideas have no proper and independent content. To see this we need only refer to the manner in which Plato introduced them. In order to make science possible he had posited certain substances independent of the sensible, and uninfluenced by its changes. But to serve such a purpose, there was offered to him nothing other than this individual thing of sense. Hence he gave to this individual a universal form, which was with him the idea. From this it resulted, that his ideas can hardly be separated from the sensible and individual objects which participate in them. The ideal duality and the empirical duality is one and the same content. The truth of this we can readily see, whenever we gain from the adherents to the doctrine of ideas a definite statement respecting the peculiar character of their unchangeable substances, in comparison with the sensible and individual things which participate in them. The only difference between the two consists in appending _per se_ to the names expressing the respective ideas; thus, while the individual things are _e. g._ man, horse, etc., the ideas are man _per se_, horse _per se_, etc. There is only this formal change for the doctrine of ideas to rest upon; the finite content is not removed, but is only _characterized_ as perpetual. This objection, that in the doctrine of ideas we have in reality only the sensible posited as a not-sensible, and endowed with the predicate of immutability, Aristotle urges as above remarked when he calls the ideas “immortalized things of sense,” not as though they were actually something sensible and spacial, but because in them the sensible individual loses at once its individuality, and becomes a universal. He compares them in this respect with the gods of the popular and anthropomorphical religion; as these are nothing but deified men, so the ideas are only things of nature endowed with a supernatural potency, a sensible exalted to a not-sensible. This identity between the ideas and their respective individual things amounts moreover to this, that the introduction of ideas doubles the objects to be known in a burdensome manner, and without any good results. Why set up the same thing over again? Why besides the sensible twofoldness and threefoldness, affirm a twofoldness and threefoldness in the idea? The adherents of the doctrine of ideas, when they posit an idea for every class of natural things, and through this theory set up two equivalent theories of sensible and not-sensible substances, seem therefore to Aristotle like men who think they can reckon better with many numbers than with few, and who therefore go to multiplying their numbers before they begin their reckoning.