Platonic Theory of Ideas

Ideas and Phenomena.

In the Timaeus (51 d and e) the existence of the "Ideas" (gu5n ) is represented as a necessary impli cation of the reality of the distinction just referred to. Were knowledge and true belief identical, there would need to be no ob jects other than those of the sensible world; if, however, they are different, there must be a corresponding difference between their respective objects. Granted that knowledge is of the nature Soc rates had disclosed, then it involves the existence of entities that are permanent, invarMble, self-subsistent,—entities that exist not merely for us or by reason of our cogitation, but in and for them selves. Although apprehended only by means of thought, they are in no sense to be conceived as products of thought. They are no mere generalisations from the so-called things of experience, even though the apprehension of them on our part may come about through the suggestions of experience. That experience should thus suggest is dependent on the fact that it is confronted by a soul which carries in itself the faculty (Pas) of apprehending the Ideas. The Ideas have, then, objective reality: they constitute, in their systematic interconnection and interdependence, the realm of absolute being.

Accordingly, there were for Plato two realms of objects, the real and the phenomenal and two modes of apprehension, thought or intellect, a pure unmixed activity of the soul, and belief or opinion, a combination of thought and perception. A large part of his philosophical work was directed to solving the problem as to the way in which these two are to be conceived as related. For he had never doubted that in some sense the world of genera tion or becoming is—that it was impossible to relegate it, after the manner of Parmenides, to the realm of non-being—although its existence could not be existence in the full significance of that term, seeing that it depended for its explanation upon what was other than itself, upon what possessed marks of which it was con spicuously destitute. Aristotle lays repeated emphasis upon the fact that the Ideas were for Plato xcoptarec, transcendent, sepa rate from the things or events of ordinary experience, and there is little or no reason to doubt the accuracy in this respect of Aristotle's account.

Nevertheless, the separation could not have been for Plato an absolute one. In the comparatively early dialogues—the Phaedrus, Symposium, Republic and Phaedo—the Ideas are definitely con nected with the process of generalisation. Wherever particulars are grouped together in a class there we may recognise to be in volved (a) an act of mind entirely distinct from sense-perception, and (b) an object which differs from the things perceived through means of the senses. It is true that the terms which are used to express the relation do not throw much light on its nature. Thus, it is said that a thing participates or shares in (ucrixcL) the Idea; that things have communion with (KoLvcovii) the Idea, or that the Idea is present to (rApeart) them; or again that the things are "imitations" or "copies" of Ideas, that the Ideas are types or models (rapaoEi7yara) after which things are fashioned. What all these different metaphors seem intended to convey is, that when we predicate of any particular thing a characteristic, we are assigning to it a feature which in and for itself cannot be sensuously apprehended, that in so far as the thing in question can be said to be knowable it is in virtue of its possessing features which in and for themselves can only be grasped by the faculty of thought. Whenever we are justified in asserting the same predi

cate of a plurality of particulars, the predicate in every case names one and the same characteristic, and it is these characteris tics which Plato called €1.677. The elbn are, in fact, universals; yet they are existent realities of which we think, and are not to be supposed to be "thoughts (voiwara) in our minds." And it is only in and through these existent realities that the particulars possess such existence as can be ascribed to them. The Etoos is the es sence of the particulars, the one in the many, though what is to be understood in this context by the word "in" was left obscure. Furthermore, an "Idea" can be "in" or "present to" a particu lar in varying degrees. A sensuous object may, for instance, be extremely beautiful, or imperfectly beautiful, while it may well be the case that no sensuous object is ever completely beautiful. From this point of view, the Idea presents itself as an Ideal towards which the things of experience can only approximate.

Intelligible Reality.

These incorporeal, changeless, self identical essences were, then, regarded as together making up the sum total of intelligible reality. The world of Ideas must be conceived as presenting an orderly arrangement from the more general to the less general, and knowledge of it could not be considered as complete until proceeding from the highest (the Idea of Good) we were able to work our way downwards without breach of continuity to the lowest, and thus exhaust the realm of being.

Hence the importance which Plato assigned to the two formal processes of dialectic—avvwycoyi, the synthetic or combining process of bringing the many under one notion, and division or classification. But in the end the procedure would appear to be frustrated, on the one hand, by the boundless sea of indeterminate particulars, and, on the other hand, by the thought of that which it is not, the thought of difference, as the inevitable shadow, so to speak, accompanying the thought of the ideal realm itself. It was the conjunction of these two features— indeterminate particularity and the opposite of being—that be came increasingly prominent in Plato's later descriptions of the phenomenal world; and in the Sophist we get perhaps the clear est indication of the line of reflection eventually pursued by him. In that dialogue emphasis is laid upon the consideration that there must be systematic relatedness among the Ideas, otherwise ra tional contemplation of them would be impossible ; and, in the at tempt to determine which Ideas are communicable with others and which are not, special stress is laid upon the important pair of Ideas, identity and difference and 06.mpov). Each abos is one with itself and shares in the nature of being and identity; it is likewise other than all the ilon besides itself, and shares, therefore, in the nature of non-being or difference.