Plato

Socrates is made to confess (5o6 d-e) that he can give no posi tive account of this supreme metaphysical principle ; he can only indicate its nature by an analogy. It is to the whole system of Forms what the sun is to the system of visible things, the source at once of their existence and of the light by which they are apprehended. The Good is thus thought of, to use scholastic terminology, as a transcendent reality which can be apprehended but never fully comprehended. The comparison with the sun and the free employment of the metaphor of "vision" indicate that the thought of the Republic is here the same as that of the Sym posium; the Good is no other than the supreme Beauty which was there said to dawn suddenly upon the pilgrim of "Love" as he draws near to the goal of the journey. R. L. Nettleship rightly says that it holds the place taken in later philosophies by God, when God is thought of as the "Light of the world." But it would be deforming Plato's thought to call the Good of the Republic "God." The Republic is permeated by religious faith, but Theism as a principle of metaphysical explanation only makes its appear ance in Plato's latest dialogues, and there as the solution of a problem which can hardly be said to have been adequately faced in the dialogues so far considered.

How the Good gives systematic structure to the plurality of Forms, the Republic does not tell us.

Development of the Doctrine of Forms.

So far we have been presented with a body of thought which has remained recog nizably the same without serious modification throughout its var ious expositions. When we come to the two works which there is reason to regard as directly preluding to the dialogues of Plato's old age, the Parmenides and Theaetetus, we are struck by a re markable difference of tone. With Plato, as with Kant, the "middle years" of life were clearly a period of fruitful critical reconstruc tion. There is an obvious motive for each reconstruction suggested by the Phaedo and Republic themselves.

The theory there expounded does not allow enough reality to the sensible world. It is quite false to say that even the Phaedo leaches an "absolute dualism" of two disconnected worlds, a realm of genuine being which never "appears" and a realm of sensible appearances which are merely unreal. What is true is that both Phaedo and Republic leave us with an unsolved problem. They tell us that a sensible thing is a complex or meeting-place of a plurality of Forms. What else, or what more, it is they do not tell us. And yet it is clear that a "thing" is not simply a bundle of "universal predicates." Or, to put the point rather differently, according to the Phaedo a thing becomes for a while beautiful because Beauty "becomes present to it." But why does Beauty become present to this par

ticular thing at just this particular moment? Clearly the relation between a"thing"and a Form which has been called"participation" needs further elucidation. Again the simple epistemological form ula that knowledge is confined to Forms and their relations, while we can only have shifting "opinions" about temporal facts does less than justice to our scientific knowledge of the natural world ; "truths of fact" have not yet come by their rights. Finally, if the Forms constitute a rationally ordered system, there must be defi nite principles of inter-relation between Forms themselves as well as between Forms and sensible things and these principles demand investigation. (If the Good is what the Republic says it is, not only will things "participate" in Forms; Forms also will "participate" in it.) Here are internal motives for active re-examination of the whole system.

It is clear that there was also an external motive. Parmenides, Theaetetus, Sophistes, all reveal a special interest in the Eleatic philosophy, and the first and third show an anxiety on Plato's part to maintain that, in spite of important divergences, he, and not the professed Eleatics, is the true spiritual heir of the great Par menides. This is easily explained when we remember that Plato was personally a friend of the chief representative of Eleaticism among the Socratic circle, Eucleides of Megara, while Polyxenus of Megara, an associate of Eucleides, was a hostile critic of the doctrine of "participation."' The doctrine of Eucleides, like that of Parmenides was that "sensible appearances" are illusions with no reality at all. Against criticism from this quarter, it would be necessary for Plato to show that the Phaedo itself does not allow too much reality to the sensible; the attempt to prove this point would inevitably show that it had conceded too little. Continued reflection on the same problem of the worth of propositions about sensible fact leads straight to the discussion of the meaning of the copula, and the significance of denial, which is the subject of the Sophistes.

Parmenides.

Formally the dialogue conducts to an impasse. In its first half the youthful Socrates expounds the doctrine of the "participation" of things in Forms to the Eleatic philosophers, Parmenides and Zeno, as the solution of the problem of the One and the Many. Parmenides raises what appear to be insoluble objections to the conception of "participation," though he admits that "dialectic" would be impossible if the existence of Forms were denied ; he hints that the helplessness of Socrates under his criticism arises from insufficient training in logic.