5. THE RELATION OF IDEAS TO THE PHENOMENAL WORLD. Analogous to the different definitions of idea are the different names which Plato gives to the sensible and phenomenal world. He calls it the many, the divisible, the unbounded, the undetermined and measureless, the becoming, the relative, great and small, not-being. The relation now in which these two worlds of sense and of ideas stand to each other is a question which Plato has answered neither fully nor consistently with himself. His most common way is to characterize the relation of things to conceptions as a participant, or to call things the copies and adumbrations, while ideas are the archetypes. Yet this is so indefinite that Aristotle properly says that to talk in this way is only to use poetical metaphors. The great difficulty of the doctrine of ideas is not solved but only increased by these figurative representations. The difficulty lies in the contradiction which grows out of the fact that while Plato admits the reality of the becoming and of the province of the becoming, he still affirms that ideas which are substances ever at rest and ever the same are the only actual. Now in this Plato is formally consistent with himself, while he characterizes the _matériel_ of matter not as a positive substratum but as not-being, and guards himself with the express affirmation that he does not consider the sensible as being, but only as something similar to being. (_Rep._ X. 597.) The position laid down in the Parmenides is also consistent with this, that a perfect philosophy should look upon the idea as the cognizable in the phenomenal world, and should follow it out in the smallest particulars until every part of being should be known and all dualism removed. In fine, Plato in many of his expressions seems to regard the world of sensation only as a subjective appearance, as a product of the subjective notion, as the result of a confused way of representing ideas. In this sense the phenomena are entirely dependent on ideas; they are nothing but the ideas themselves in the form of not being; the phenomenal world derives its whole existence from the ideal world which appears in it. But yet when Plato calls the sensible a mingling of the same with the different or the not-being (_Tim._ p. 35), when he characterizes the ideas as vowels which go through every thing like a chain (_Soph._ p. 253), when he himself conceives the possibility that matter might offer opposition to the formative energy of ideas (_Tim._ p. 56), when he speaks of an evil soul of the world (_de Leg._ X. 896), and gives intimations of the presence in the world of a principle in nature hostile to God (_Polit._ p. 268), when he in the Phædon treats of the relation between body and soul as one wholly discordant and malignant,—in all this there is evidence enough, even after allowing for the mythical form of the Timæus, and the rhetorical composition which prevails in the Phædon, to substantiate the contradiction mentioned above. This is most clear in the Timæus. Plato in this dialogue makes the sensible world to be formed by a Creator after the pattern of an idea, but in this he lays down as a condition that this Demi-urge or Creator should find at hand a something which should be apt to receive and exhibit this ideal image. This something Plato compares to the matter which is fashioned by the artisan (whence the later name _hyle_). He characterizes it as wholly undetermined and formless, but possessing in itself an aptitude for every variety of forms, an invisible and shapeless thing, a something which it is difficult to characterize, and which Plato even does not seem inclined very closely to describe. In this the actuality of matter is denied; while Plato makes it equivalent to space it is only the place, the negative condition of the sensible while it possesses a being only as it receives in itself the ideal form. Still matter remains the objective and phenomenal form of the idea: the visible world arises only through the mingling of ideas with this substratum, and if matter be metaphysically expressed as “the different,” then does it follow with logical necessity in a dialectical discussion that it is just as truly being as not-being. Plato does not conceal from himself this difficulty, and therefore attempts to represent with comparisons and images this presupposition of a _hyle_ which he finds it as impossible to do without as to express in a conceivable form. If he would do without it he must rise to the conception of an absolute creation, or consider matter as an ultimate emanation from the absolute spirit, or else explain it as appearance only. Thus the Platonic system is only a fruitless struggle against dualism.