Plato, a Greek philosopher, born in Athens (or according to some authorities in .zEgina) about 429 B. 0., died about 348. His father Ariston traced his descent to Oodrus, and his mother Perictione reckoned Solon among her ancestors. His original name was Aristocles, derived from his grandfather; but it was altered to Plato (Gr. Plato 1300582 , broad), whether from the breadth of his forehead, his shoulders, or his diction, is not determined. Owing to his subsequent renown a parentage from Apollo was attributed to him, and bees settling on his infant lips were said to have betokened the honeyed sweetness of his style. Besides the ordinary training in gymnastics, grammar, and music, he was initiated by Cratylus into the doctrines of Heraclitus, and the study of An-axagoras gave him the results of the pre-So-cratic physics. The exuberant fancy which he subsequently lavished on dialectics at first overflowed in poetical compositions, epic, lyric, and dramatic. But he burned his epics on comparing them with Homer, and having in his 20th year fallen under the influence of Socrates, he thenceforth devoted himself to philosophy as that essence and soul of harmony of which rhythmical numbers are but the sensuous and shadowy embodiment. He was a pupil of Socrates during the last eight or nine years of that great reformer's life, and became thoroughly imbued with his profound ethical spirit, and master of his searching and potent dialectics.

Plato alone, of all the disciples of Socrates, seems fully to have appreciated the intellectual greatness and seized the profound scientific conceptions of his master; and hence, while others, looking at single aspects of the Socra-tic teaching, framed one-sided systems which rather caricatured than adequately represented it, Plato developed its germs in all their fulness and fruitfulness; and his works are not more a product of his own genius than a tribute to the memory of his master. After the death of Socrates, Plato repaired to Megara, where Euclid, a former fellow disciple, had opened a school in which he sought to engraft the Socratic ethics on the stock of Eleatic idealism. To the ideas and impulses here acquired we owe very probably that group of dialogues in which Plato seeks to establish, against the Heraclitan doctrine of absolute multiplicity and the Eleatic assumption of absolute unity, the true idea of science. From Megara he visited Oyrene, Egypt, Magna Grsecia, and Sicily. Of alleged journeys to Palestine, Babylon, Persia, India, etc, there is not the slightest evidence; and even of any philosophical fruits of his sojourn in Egypt his writings indicate but the faintest trace.

In the Greek cities of lower Italy, however, where Pythagoreanism had its native home and still mainly flourished, he became more thoroughly conversant with the tenets of that philosophy. Hence in part probably his fondness for mathematical physics, for mythical and allegorical imagery, and possibly for political speculation, while its fundamental doctrine of unity developing itself in multiplicity furnished an admirable solution of the conflict between the Eleatic and the Heraclitan doctrines. Plato's general mode of philosophizing was in antiquity regarded as strongly Pythagorean. After about 12 years of foreign residence and travel he returned to Athens, and opened a school in his garden near the Academy, where he expounded his doctrines in conversation and formal lectures to a large number of pupils, among whom were women disguised as men. He also devoted a portion of his time to composing and revising his works. . His life thus flowed on in an even tenor, broken only by two visits to Syracuse, neither of them attended by very flattering results. One was made apparently in the vain hope of realizing through the newly crowned younger Dionysius his ideal republic.

Plato never married, never mingled in public affairs, and seems to have regarded the constitution and character of his native city with disfavor and almost despair. He spent a tranquil old age, his mental faculties to the last scarcely perceptibly decayed. - The writings of Plato have come down to us in a state of unusual completeness and purity. The genuineness of many of the pieces which bear his name has been disputed, but in the case of most of them with little approach to unanimity on the part of the assailants, A few of the smaller pieces, together with the letters, are undoubtedly spurious, but the genuineness of all the more important works there is no good reason to doubt. They are all in the form of dialogues; in nearly all Socrates is the chief speaker, and the exponent of the author's sentiments. Their composition extended over a large part of his life, and they are probably to be regarded rather as marking different stages of his philosophical development, than as expositions of a perfectly matured and rounded system. The methods of philosophy Plato seems to have settled with great definiteness; but in regard to the subject matter to which those methods were applicable, he to the last regarded himself as an inquirer.

Numerous attempts have been made to arrange his dialogues on some clear principle of classification, either logical or chronological. Aristophanes of Byzantium arranged a part of them together in trilogies; and Thrasyllus, in the time of Tiberius, divided the whole number into tetralogies, which arrangement has been adopted by K. F. Hermann in his edition of Plato's works (1851). No one of these plans or modes of arrangement, however, has been entirely successful or acceptable to scholars. The dialogues bear no clear internal marks of the time when they were written, and they usually admit no sharp division according to their contents. We may perhaps most satisfactorily class them according to the leading epochs in the life of Plato. Thus some of the smaller dialogues on specific ethical points may be referred to his first or more strictly Socratic period. To his residence in Megara we may refer, doubtless, the noble tetralogy of "Theaetetus," the "Sophist," the "Statesman," and "Parmenides;" and finally, to the period of his establishment in the Academy those noble compositions, "Phaedrus," the "Symposium," "Gorgias," "Phsedo," "Phi-lebus," the " Republic," " Timseus," and the "Laws;" though in what order it is impossible to decide, except that we may naturally regard "Phsedrus " as the earliest work of this period, while the "Laws," by unanimous consent, is among the latest.

Plato is one of the most fascinating writers that ever undertook to expound the enigmas of philosophy. He spreads the charms of an exhaustless fancy over the subtlest controversies of the dialectician. He is at once poet and philosopher, with no small measure of the sweet flow of diction, the richness of invention, the exuberant imagery, the never failing vivacity, and we may add the garrulity, of Homer. One of the highest charms of his writings is their thoroughly dramatic character; they are dialogues not merely in form but in spirit. A light, buoyant humor, irony, sarcasm, banter, now broad and now delicate, picturesque illustration, and occasionally elaborate and gorgeous fable, alternate with and relieve the stern dialectical processes. It is necessary to any exposition of the philosophy of Plato to keep in view his historical position. The field of science had received as yet no formal divisions, but the several schools before Socrates had, each for itself, sought to solve the problem of universal being. Socrates discarded the whole body of these speculations as aiming at what was unattainable, and worthless if attained.

He threw himself entirely on questions of political and personal morality, as those which alone had an immediate interest for man, and investigated these by that searching process of question and answer in which he sought to draw forth an exact conception of the subject, and to distinguish it from all related or unrelated ideas. Definition and generalization were the essential elements of the Socratic method, which Plato adopted to the full and developed scientifically. But he readmitted those elements of speculation which Socrates had discarded, bringing to bear upon them his new dialectical weapons, and thus made his system the embodiment and representative of all the wisdom of his time. - Plato makes no formal division of science. He evidently, however, regards it substantially under the threefold division of dialectics, physics, and ethics or politics. Dialectics, which with Aristotle became the mere instrument of science, logic, was with Plato the science of sciences, the science of absolute being. Physics and ethics are sciences only so far as they connect themselves with dialectics. Strictly speaking, therefore, dialectics covers the whole field of philosophy, while speaking in a looser way it appears as one single, though far the most important branch of it.

Mathematics he does not regard as a science, but a help to science, lying midway between its absolute verities and the uncertainties of opinion. Dialectics, as the science par eminence, deals only with the absolute and invariable. Its subject matter consists of those transcendental, spiritual essences which Plato calls forms, species ( Plato 1300583 ), improperly known as ideas. It is easy to say in a general way what these forms are. They are the eternal, immutable essences, removed from the sphere of sense, and cognizable only by the reason. They pervade the sensible world, being as it were the substance of which it is the shadow, giving to it whatever of partial reality it possesses. They thus answer undoubtedly as near as may be to the intuitions and general concepts of modern metaphysics, and they are now more generally explained as mere abstractions, universals, the product exclusively of the mind, and having no objective reality. Earlier scholars-held them to be veritable, objective existences, subtle, half spiritual, and discerned directly by the eye of the soul, as sensible objects are by the eye of the body. Much as there is in Plato which gives plausibility to the more modern view, we yet incline decidedly to the realistic doctrine of former interpreters. The ideas or forms of Plato grew out of his strong conviction of the non-reality of matter. He adopted fully, in regard to the phenomenal world, the Heraclitan doctrine of the perpetual flow of all things.

Thus, denying the reality of matter, which never is, but is always becoming, he would have denied equally the possibility of forming a science by generalizations from matter. It could have been but the shadow of a shadow. The same thing is shown by the relation of Plato's doctrine to the Eleatics. The Eleatics were not idealists in the modern sense of the term. Their absolute One was not a mere abstraction, a creature of the mind, but the totality of the objective universe, as discerned by the soul or the reason, itself but a subtler species of matter. It is doubtful if there was any pure idealism in antiquity. Again, the way in which we become acquainted with the " forms " proves their objective and real character. Were they mere intuitions or generalizations, we could arrive at a knowledge of them by those processes of abstraction and generalization to which the mind is abundantly competent. But such was not the case. The soul enshrined in the body could not, according to Plato, possibly arrive at this knowledge. It must have acquired it in a state anterior to the present, when, disembodied, it stood face to face with these essences kindred to itself, and communed with them as the bodily sense here holds converse with the elements of matter.

Thus all learning is with Plato merely reminiscence, the knowledge which the soul had in its anterior state being called up by the action of the senses upon the phenomenal world, in whose pictured semblances the soul learns to recall the features of the divine original. And that this doctrine of pre-existence and reminiscence is no mere poetic fiction or imaginative symbol is shown by the severity of the process which he employs in demonstrating it, and the high practical purpose to which he applies it. In order to establish the doctrine of preexistence he employs one of the sharpest psychological processes in his entire works. He distinguishes between ideas drawn from the sense and those conceptions which sense never could furnish, but which exist in the mind from the very commencement of our earthly being, as standards to which our sensible perceptions are all referred, and which consequently it must have brought with it from an anterior state. And in thus establishing the existence of the soul before coming into the body, he establishes its independence of the body, and by consequence its immortality. He reasons from the past to the future, and by showing that the soul is not dependent for its existence upon the body, he shows that it is not affected by the dissolution of the body.

Preexistence, the ideas or forms, and immortality are thus all woven into one indissoluble web of argument, of which the ideas are, as everywhere in his system, the central point. We hold, therefore, to the middle-age realistic views of the Platonic forms or ideas, and the attempt to reduce them to the standard of the Scotch or French metaphysics of our own day is to ignore Plato's historical position, and lose sight of the peculiar problems of Grecian speculation. Of course it is impossible but that Plato, in applying to these assumed realities his sharp dialectical methods, should be sometimes inconsistent with himself, and resolve the objective essences into the subjective conceptions for which they really stand. And as these transcendental forms are the essence of all reality, and the end of all true knowledge, it follows that the soul's residence in the body is an evil, that the phenomena of sense, interposed between the mind and these absolute existences, are constantly deceiving and alluring it from its proper element.

The great business of the philosopher, therefore, is to emancipate himself as far as possible, not only from the dominion of the animal appetites, but also from the illusions of sense, and to retire into that interior world of reflection in which his mind can commune with its kindred eternal essences. The "ideas," however, are not themselves all of equal excellence; but supreme above the others are the forms of the true, the beautiful, and the good, in which triad again the last takes the highest place, and becomes, perhaps, identical with the Deity, who thus, under the Platonic conception, seems to fluctuate between a personal being and the highest and noblest of the ideas. And as the ideas are the only object of true science, and preparation to commune with them, and especially with the good, the noblest of them all, is the great end of philosophical striving, so in the last analysis science and virtue coincide, and the ideas furnish the basis not only of all science, but of piety and morality. - Physics Plato expounds in a great measure from a Pythagorean standpoint, and his cosmogony in most of its details scarcely rose, probably, even in his own view, above the level of plausible conjecture. The world is originated and not eternal.

It is framed by the Creator out of a chaotic and formless mass, after the model of an immovable and perfect archetypal world. The two are brought into union through the medium of a world-soul, placed in the world according to the relation of numbers, and constituting a harmonizing link between the Deity and the archetypal world on the one hand, and blind and formless matter on the other. As the work of a good being, the world must be as perfect as the untractable and essentially evil nature of matter admits. Hence the universe is a unity, and has the most perfect of all forms and motions, the spherical and the circular. The stars are heavenly and imperishable essences, and the earth lies, round, self-poised, and immovable, in the centre of the world. The soul, according to Plato's conception of its nature, would come into the department of physics. It consists, in his view, of two portions, the soul proper, the intellect or reason, divine and immortal, and a sensuous or appetitive principle, material and perishable; while intermediate between them, but approaching nearer to the reason, is a third element which he calls passion, and which thus mediates between the divine and the earthly, the intellectual and the sensuous, as the soul of the world mediates between Deitv and matter.

The immortality of the soul Plato maintains at length and with great earnestness. He argues it from the general principle that contraries spring from contraries, death from life, and consequently life from death, from the soul's preexistence and consequent independence of the body, from its simplicity which renders it incapable of dissolution, from its superiority to the body, from its bearing within it the principle of life, etc. The soul's own proper evil, viz., sin, does not annihilate it; much less then can an alien and merely incidental evil, like the dissolution of the body, have any such power. He believes in future retribution, exonerates God from responsibility for sin and suffering, and sets forth in elaborate myths the blessedness of the virtuous and the punishments of the vicious, blending, however, with his teaching the Pythagorean doctrine of metempsychosis. - In ethics Plato holds to the Socratic doctrine that virtue is a science and consequently matter of instruction. Virtue is essentially one, the good, but has various forms of development. He retains the fourfold division of the virtues into wisdom, courage, temperance, and justice.

The first three ally themselves to the three divisions of the soul respectively, wisdom being the proper virtue of the intellect, courage of the passionate portion, and temperance of the animal or sensuous. Justice is the principle that pervades and regulates the whole. In discussing the nature of the chief good, which the ancients made the starting point of their ethical system, Plato avoids the opposite extremes of cynicism and hedonism, that on the one hand which excludes pleasure, and that on the other which makes it identical with pleasure. True virtue always carries with it its own enjoyment, and the virtuous man, another name for the philosopher, finds his highest happiness in communion with and assimilation to the good and the divine. Politics with Plato, as with the Greeks generally, are closely allied to ethics. The state is but the individual on a larger scale; the individual but a miniature state. Hence for purposes of moral analysis Plato turns from the individual to the state, as in deciphering an inscription he would turn from smaller and more obscure to larger and more legible characters. His analysis of a state is but an enlargement of his psychological analysis. Its division is threefold.

The governing class represent the intellect, the essence of the soul, the laborers and handicraftsmen its sensuous and appetitive portions, and the soldiers or guards the intermediate passionate element. The virtue of the first class is wisdom, of the second temperance, and of the third courage; while in the state, as in the individual, justice is the principle that runs through, regulates, and harmonizes the whole. According to the ordinary Greek conception, Plato makes the state supreme, and merges in it all the interests of individual and domestic life. Household relations and ties are to be unsparingly sacrificed on the altar of the state. A community of wives and of goods is to take the place of domestic life and of private property. The education and the employments of the citizens are all to be regulated by the state. Plato draws out at length his system of education. He would banish all dramatic poetry as involving the personating of fictitious characters, and thus virtually sanctioning falsehood, all music except the simpler and more manly kinds, all those fables which exhibit degrading pictures of the.gods, and everything that can foster timidity and the fear of death.

The governing class in the state should consist of philosophers - of those who, having risen to the contemplation of the real and the true, can estimate at their worth the shadowy pursuits and pleasures of the multitude. A monarchy is to be preferred on account of the difficulty of finding many men qualified to rule. In the "Laws," however, Plato abandons the monarchical theory for that of a mixed government. His views are decidedly aristocratic, and he would devolve all the privileges of the government on the two higher classes, while the multitude are merely to be kept under wholesome restraint.

Slavery Plato would tolerate, but only the enslaving of barbarians, not that of Greeks by Greeks. - A tendency to a trinity of doctrines runs through the philosophy of Plato. In psychology we have the trinity of reason, passion, and appetite; in ethics, of wisdom, courage, and temperance; in ontology, of being, becoming, and not being; in knowledge, of science, opinion, and sensation; in cosmogony, of God, the soul of the world, and matter; in the state, of magistrates, warriors, and laborers. The list might be prolonged still further. Plato, of all authors, is the one to whom the least justice can be done by any formal analysis. In the spirit which pervades his writings, in their untiring freshness, in their purity, love of truth and of virtue, their perpetual aspiring to the loftiest height of knowledge and of excellence, much more than in their positive doctrines, lies the secret of their charm and of their unfailing power. Plato is often styled an idealist. But this is true of the spirit rather than of the form of his doctrine; for strictly he is an intense realist, 'and differs from his great pupil, Aristotle, far less in his mere philosophical method than in his lofty moral and religious aspirations, which were perpetually winging his spirit toward the beautiful and the good.

His formal errors are abundant; but even in his errors, the truth is often deeper than the error; and when that has been discredited, the language adjusts itself . to the deeper truth of which it was rather an inadequate expression than a direct contradiction. - Among the translations of Plato, the most distinguished is the Latin version of Mar-silius Ficinus, in which the printed works of Plato were first given to the world (Florence, 1483). A German translation by Schleier-macher, never completed, is admirable, and is accompanied by learned introductions which have been translated into English. The latest and best German translation is by Steinhart and Miiller. Plato has been translated into French by Victor Cousin, and there is an Italian version by Dardi Bembo. In English, the translation by Thomas Taylor (5 vols. 4to, 1804) is marred by its author's very imperfect acquaintance with Greek. The earlier and much better version of Floyer Sydenham (1767-'-80), of which Taylor's is a continuation, embraced but nine dialogues; and the translation in Bohn's " Classical Library " (6 vols., 1848-54), by different hands, is very unequal and of no special value.

Recently an admirable translation of Plato's entire works has been made by Prof. Jowett, master of Balliol college, Oxford (4 vols. 8vo, 1871), with elaborate analyses and introductions to the several dialogues, leaving almost nothing to be desired for the understanding and application of the original. Among the translations of the separate works may be mentioned that of the " Republic " by Davies and Vaughan, that of the "Philebus " by Edward Poste, and that of the "Gorgias" by E. M. Cope. Editions of the entire or separate works are very abundant. The first edition (Venice, 1513) was arranged in tetralogies, according to the division of Thrasyllus. In that of Henry Stephens (3 vols., 1578) much pains was bestowed on the correction of the text. This was reprinted in the Bipont edition (11 vols., 1781-'6), with the Latin version of Marsilius Ficinus. Immanuel Bekker first brought the text into a satisfactory condition (Berlin, 1816-18), which text was reprinted by Priestley in a variorum edition (11 vols., London, 1826), the last two volumes containing the Latin version of Ficinus, and was still further corrected by Ast (9 vols., Leipsic, 1819-'27). Since then many able German scholars have devoted time and labor to the editing and elucidation of Plato, among whom may be named Baiter, Orelli, Winckel-mann, Hermann, Hirschig, and Stallbaum. Stallbaum's edition, in Jacob and Rost's Bibli-otheca Grceca, with special introductions and full Latin notes, is by far the best annotated working edition of Plato. Among the useful subsidiary works for the study of Plato are Zeller's Platonische Studien (1839) and So-krates und dit Sokratische Sbhule (1868); T. H. Martin's Etudes sur le Timee (1841); Van Heusde's Initia Philosophies Platonicce (2d ed., 1842); Bonitz's Platonische Studien (2 vols., 1858-'60); Whewell's " The Platonic Dialogues for English Readers " (3 vols., 1859-'61); and Grote's "Plato and the other Companions of Socrates" (3 vols. 8vo, 1865).