Dialogues

pass into one another was a matter of experience “on a level with the cobbler’s understanding” (“Theaetetus” 180 D). But how could philosophy explain the connection of ideas, how justify the passing of them into one another? The abstractions of one, other, being, not-being, rest, motion, individual, universal, which successive generations of philosophers had recently discovered, seemed to be beyond the reach of human thought, like stars shining in a distant heaven. They were the symbols of different schools of philosophy: but in what relation did they stand to one another and to the world of sense? It was hardly conceivable that one could be other, or the same different. Yet without some reconciliation of these elementary ideas thought was impossible. There was no distinction between truth and falsehood, between the Sophist and the philosopher. Everything could be predicated of everything, or nothing of anything. To these difficulties Plato finds what to us appears to be the answer of common sense⁠—that Not-being is the relative or other of Being, the defining and distinguishing principle, and that some ideas combine with others, but not all with all. It is remarkable however that he offers this obvious reply only as the result of a long and tedious enquiry; by a great effort he is able to look down as “from a height” on the “friends of the ideas” as well as on the pre-Socratic philosophies. Yet he is merely asserting principles which no one who could be made to understand them would deny.

The Platonic unity of differences or opposites is the beginning of the modern view that all knowledge is of relations; it also anticipates the doctrine of Spinoza that all determination is negation. Plato takes or gives so much of either of these theories as was necessary or possible in the age in which he lived. In the “Sophist,” as in the “Cratylus,” he is opposed to the Heracleitean flux and equally to the Megarian and Cynic denial of predication, because he regards both of them as making knowledge impossible. He does not assert that everything is and is not, or that the same thing can be affected in the same and in opposite ways at the same time and in respect of the same part of itself. The law of contradiction is as clearly laid down by him in the Republic (IV 436 and following; V 454 C, D), as by Aristotle in his Organon. Yet he is aware that in the negative there is also a positive element, and that oppositions may be only differences. And in the “Parmenides” he deduces the many from the one and Not-being from Being, and yet shows that the many are included in the one, and that Not-being returns to Being.

In several of the later dialogues Plato is occupied with the connection of the sciences, which in the “Philebus” he divides into two classes of pure and applied, adding to them there as elsewhere (“Phaedrus,” “Cratylus,” Republic, “Statesman”) a superintending science of dialectic. This is the origin of Aristotle’s Architectonic, which seems, however, to have passed into an imaginary science of essence, and no longer to retain any relation to other branches of knowledge. Of such a science, whether described as “philosophia prima,” the science of ousia, logic or metaphysics, philosophers have often dreamed. But even now the time has not arrived when the anticipation of Plato can be realized. Though many a thinker has framed a “hierarchy of the sciences,” no one has as yet found the higher science which arrays them in harmonious order, giving to the organic and inorganic, to the physical and moral, their respective limits, and showing how they all work together in the world and in man.

Plato arranges in order the stages of knowledge and of existence. They are the steps or grades by which he rises from sense and the shadows of sense to the idea of beauty and good. Mind is in motion as well as at rest (“Sophist” 249 B); and may be described as a dialectical progress which passes from one limit or determination of thought to another and back again to the first. This is the account of dialectic given by Plato in the Sixth Book of the Republic (511), which regarded under another aspect is the mysticism of the “Symposium” (“Symposium” 211). He does not deny the existence of objects of sense, but according to him they only receive their true meaning when they are incorporated in a principle which is above them (Republic VI 511 A, B). In modern language they might be said to come first in the order of experience, last in the order of nature and reason. They are assumed, as he is fond of repeating, upon the condition that they shall give an account of themselves and that the truth of their existence shall be hereafter proved. For philosophy must begin somewhere and may begin anywhere⁠—with outward objects, with statements of opinion, with abstract principles. But objects of sense must lead us onward to the ideas or universals which are contained in them; the statements of opinion must be verified; the abstract principles must be filled up and connected with one another. In Plato we find, as we might expect, the germs of many thoughts which have been further developed by the genius of Spinoza and Hegel. But there is a difficulty in separating the germ from the flower, or in drawing the line which divides ancient from modern philosophy. Many coincidences which occur in them are unconscious, seeming to show a natural tendency in the human mind towards certain ideas and forms of thought. And there are many speculations of Plato which would have passed away unheeded, and their meaning, like that of some hieroglyphic, would have remained undeciphered, unless two thousand years and more afterwards an interpreter had arisen of a kindred spirit and of the same