merely a vain display of logical skill and clever cavilling, but had for its object the removal of the unstable ground on which opinions may have been rested, and the formation of more settled convictions :-indeed, it was exalted by him into a regular discipline of the mind set in operation for the single purpose of investigating the truth. The method and discipline by which he accomplishes this object is, what he calls DIALECTIC, which, as opposed to the plans of the Sophists, may be termed the true art of Discussion; and, as contrasted with the mere wisdom of opinion, (the doooopía of the Sophists,) it was philosophy-real science-the knowledge of the truth. The ground of his whole proceeding was the Fallaciousness of Opinion; and hence Plato had to seek some criterion of Truth apart from mere opinion. Denying the sufficiency of subjective truth (i. e. the assumption that the mental perceptions are true simply because they take place), he set himself to search after objective truth-truth independent of the mind of man and not affected by the variations of human judgment—as a foundation of his system of knowledge. Involved with the notion of the Fallaciousness of Opinion, another is closely allied,—the Fallaciousness of the Senses; and it is the joint application of these two fundamental principles, which unites his method and his philosophy in one master-science,-Dialectic. True knowledge, unlike that derived through the senses, is founded purely on the apprehensions of the intellect, without any intervention whatever of the senses; -and so also Dialectic, as being philosophy, is occupied about that which exists (rò övтwç öv), or has Being, in opposition to the presentations made to the senses, which are conversant only with those things that have the semblance of being (rà paivoμéva); —while, as a method, it investigates the reason or account of the Being of everything,-of everything as it is, and not as it APPEARS, not being satisfied with opinions, of which no account can be given, but bringing all to the test of exact argument and definition. Plato thought it his first business, therefore, to give his method a firm basis by establishing at the outset a sound Theory of Being, as a sure Criterion of Truth ;—and this is his celebrated Theory of IDEAS. Plato conceived, that Opinion, in contradistinction from Knowledge, is grounded on sensation and becoming (rò yiyvóμevov). To man, indeed, such sensation is absolutely necessary; because the soul resides in the body, which is itself a compound thing, subject to continual decay and reproduction, the connexion between the two consisting in the reciprocal communication either of action or passion by means of their respective faculties. Hence sensation is clearly regarded as an effect produced by the union of the soul with the body; and Plato did not fail to observe that although sensation, strictly speaking, has cognisance only of corporeal qualities, there are certain internal states of the soul which have no immediate reference to the corporeal. The soul, in short, receives sensations through the sensuous mechanism; but it has moreover, (in addition to the power which it exercises through the instrumentality of the bodily organs,) a distinct faculty of investigating by itself the abstract properties of all sensations; "appearing," as it is said in the Theætetus (p. 185. b.) "to have the power of inspecting the common propertiesof all things." In accordance with this view, Plato distinguishes what is apprehended by the senses (7ò aia0ŋróv) from that of which we become cognisant by means of reflection (diávoia) through the understanding or rational contemplation (λογισμός or νόησις) ;-the former being in a continual state of transition or becoming (rà yıyvóμɛva), whereas the latter (rà övra) are constant and permanent, unproduced, imperishable, and ever identical with themselves, belonging to ovcía and capable of becoming the objects of science or certain knowledge. Such are the notions of genus and species, the laws and ends of nature, as also the principles of cognition and moral action, and the essences of individual, concrete, thinking souls ;-respecting all of which may be predicted an ɛldog, which closely corresponds with what we now designate-a general term. (Comp. Republ. vii. p. 532. a., with Phileb. p. 15. a., and Tim. p. 51. c.) It is in this sense, then, that he says of science in general (which seeks in the ideas to seize the essence of things), that its object is to exhibit everything as it is, by itself, absolutely, (rò avrò Kal avтò, or Tò avτò ĚKασTOV, as in Republ. vi. p. 494. a.) and that the ideas themselves invariably maintain their proper nature, character, and identity. All things else, therefore, besides ideas, have only so far a reality, as they participate therein;-all being formed out of ideas and numbers,*-sensible things merely resembling ideas and being, as copies do originals,-just as Plato himself observes in the tenth Book of the Republic,-speaking of a couch, οὐ τὸ ὂν, ἀλλά τι τοιοῦτον οἷον τὸ ὄν. Inquiry, however, must necessarily lead men from one idea to others in connexion therewith; and on this account Plato regarded individual ideas as hypothetical notions, for which a true foundation can only be given by an idea not requiring explanation and confirmed also by some higher supposition or idea. He wished, indeed, through the realisation of the lower ideas to rise to a knowledge of the highest, which represents the principle of all things,—in short, the idea of God,—God, the measure of all things (not man, as Protagoras held),—God, the beginning, the middle, and the end of all,-the Supreme Idea, containing in itself all others, and the unity which in itself comprises the true essence of all things. In conclusion, as Ritter succinctly and well `observes, "Plato attempted to account for the existence of the sensible world, by the ideas alone, without recourse to any other nature, alien and foreign to them; and in this attempt to make the transition from the ideal to the sensible, there is much that is vague and indeterminate. The source of this vagueness lies principally in the insufficiency of the distinction which he makes between different ideas, as indicating either a substantial and absolute entity, or a mere relation or property. To this must be added the vague and indeterminate sense of the Platonic idea of the essence which is exhibited by the ideas severally. In this respect Aristotle does not seem to be to blame, when he asks how ideas or lifeless numbers can possibly have a desire, or longing, notwithstanding that we are constrained to admit that, according to Plato, some ideas, at least, that of the soul for instance,-must be supposed to be endued with life. Again, the distinction which is made between * Θεὸς οὕτω δὴ τότε πεφυκότα ταῦτα πρῶτον διεσχηματίσατο εἴδεσί τε καὶ ἀριθμοῖς. "God thus truly formed these things as they first arose according to ideas and numbers."-Tim. p. 53. b. ideas in their unity and totality, and ideas in their opposition to each other, is extremely vague; although it is the basis on which the whole theory rests. If moreover, we admit that, according to man's true and real nature, the world of ideas is his proper home, and that he there contemplates the true essence of things, as is implied in the doctrine of reminiscence, it becomes difficult to account for his removal from so perfect a state of being, into the present imperfect existence. Finally, Plato was forced to have recourse to the notion, that there is an impelling necessity in the secondary causes, the ground of which was the supposition, that there must be a something opposite to good. In this there is undoubtedly contained a very ancient cast of thought, still the very indefinite nature of this necessity shows that, after all his attempts to reconcile the supra-sensible with the sensible, Plato still found in it something inexplicable. Thus much at least is certain, that on the one hand, the tendency of his views was to refer all real entity to the immutable ideas, and consequently to consider the sensible more as an unsubstantial shadow than a reality; while, on the other, he seems never to have forgotten that the only point of view from which philosophical speculation is possible, lies on the sensible, and so again the reality of the sensible appears to be a necessary supposition of his system. In these two tendencies, we may recognise the well-balanced and measured character of his mind. To discover their true connection however, was granted neither to Plato nor his age; nor can we wonder, then, that he should have had recourse to many vague and loose conceptions in order to explain it, none of which, however, eventually satisfied his own mind. The dialectic of Plato, however great its defects may be estimated, presents, nevertheless, a worthy image of the pure philosophical feeling. This Plato assumed to be grounded in love and in a longing after the eternal ideas, by the contemplation of which the mortal soul sustains itself, and by perpetual renovation becomes participant in immortality. Stimulated by such a desire, the philosophical mind or soul strives to attain, as far as possible, to a perfect remembrance of ideas which are the eternal essence of things, the memory of them being awakened by sensible phenomena, which are resemblances of the ideas and real b entity, and thereby serve as means by which the cognition of real being becomes attainable. But while the sensible, by bringing to mind this resemblance to real entity, is subservient to the efforts of the reasonable soul, it also impedes and limits it in its pursuits of the true, since the sensuous representations contain as much of irresemblance as of resemblance. But the greatest impediment to philosophical investigation arises from the constant flux of sensation which allows it no stability. Flowing on in a continual series of production and decay, sensible things are constantly changing their state and never exhibit the full perfection of the subsistent. They comprise at once entity and non-entity, and it is not the true standard and the all-sufficient which they represent, but only the relative, which constantly varies by greater or less from the measure of the true and substantive entity. It was to this that Plato looked when he thought he had discovered in the ideas of the other and the relatively great and little, the grounds of the sensible matter of mutability. But contingent being is only for the absolute, a mean merely by which the resemblance to ideas is manifested in sensible things; and, viewed in this light, ideas must appear as the ends of sensible existence, and as the standard by which the true therein is to be measured. A multiplicity of ends having been admitted, it followed that there must also be a last end,- —an ultimatum in the realm of ideas,-therefore a supreme idea. This result follows from the consideration of the mutual relation of ideas, for one idea must be explained by another, and thus we proceed through a series of subordinate ideas up to higher and higher, ir order to reduce them by a legitimate synthesis into unity, until at last we arrive at the highest idea, and then again, by a converse method, to descend by analysis from the supreme unity to the multiplicity of subordinate ideas. In this higher and lower ordination, each subordinate idea requires merely as a supposition until it is shown by the latter to be legitimate. But from such hypotheses or suppositions the mind must at last arrive at that which implies nothing else, and is in itself sufficient; of this kind is the nature of good, which, exhausting all true entity, is itself in want of nothing, but is desired by all. This idea of good, or God, is consequently the key-stone of all |