Part I. GREEK PHILOSOPHY – Sect. 3. The Systematic Period

The third period of Greek philosophy may be said to combine the two former periods, in so far as consideration was now given to both metaphysical and moral problems. The union was not so much a natural outcome of the times as the work of the great personalities who have stamped the period with their genius.

The general questions regarding being, with which the earlier philosophers were concerned, had largely lost their interest under the influence of the Sophists, and the natural trend of thought was towards practical matters. The fact that philosophy returned with renewed vigour to the great problems of metaphysics and reached its climax in this direction, was due to the commanding influence of the two great men who now appeared in history—Plato and Aristotle.

That which differentiates the philosophy of these eminent teachers is the systematic character of their work. Each gave to the world a many-sided, all-embracing system of philosophy complete in itself.

Yet while both Plato and Aristotle dealt with the entire circle of scientific subjects, their systems are not repetitions of each other. Each dealt with the various themes raised from his own standpoint and infused into his system his own personality.

Plato may be said to present a counterpart to the earlier physical theories of the universe, and his idealism is to be regarded as the antithesis of the materialism of Democritus and of the sensationalism of the Sophists.

From Plato again there springs the imposing form of Aristotle, the greatest teacher the world has yet produced. His system, which embraces the entire contents of philosophy, combines the isolated results attained by all previous philosophers in one harmonious whole, and thus affords the most perfect expression of Greek thought.

Chap. I. Plato

Plato (427-347) was born at Athens during the early years of the Peloponnesian war, in the same year as Pericles died. He came of an aristocratic family, his father boasting his descent from Codrus, the last king of Athens. Legend gathered around his name, and the story was current that he was descended from the gods. His real name was Aristocles, but he was called Plato, either on account of his broad shoulders or broad forehead.

Plato was an aristocrat not only by birth, but by temperament. Unlike Socrates, who was a man of the people, he had a contempt for the masses, and withdrew himself from public life. He made no attempt to enter on a political career, though he had exceptional opportunities of doing so, but devoted himself to study. He would be about fifteen when the expedition to Sicily was undertaken, and he may have witnessed the great fleet sailing out in pomp from the harbour of Piraeus; and two years afterwards he must have shared in the general despair when the news came that the fleet and the flower of the army had perished, and with them the hope of Athena. There was little indeed to tempt a man of Plato’s spirit to mingle with the politics of the day. The great statesmen, and with them the bloom of the Periclean age, had passed away. The long war had done its work and had well-nigh exhausted both the revenues and strength of Athens. Revolution followed revolution so rapidly that public confidence in the Constitution was fast disappearing, and men of talent and honour were beginning to despair of their country and withdraw themselves from public life. There is a story told that Plato thanked the gods for four things : that he was born a man, a Greek, an Athenian and a contemporary of Socrates. This last blessing was probably the most determinative factor in shaping his life. He early came under the influence of Socrates, whose intercourse he enjoyed for eight years. After the death of his master, he seems to have undertaken extensive travels, visiting Egypt, Italy and Sicily.

In his 40th year he returned to Athens, where he began to teach in the Academy, a place of exercise in the western suburb of Athens, planted with a grove and named from the hero Academus. Here he gathered around him a band of disciples, teaching them after the manner of Socrates, mainly by conversation, and embodying the results of his teaching in his written dialogues. His philosophic seclusion was twice broken by visits to Sicily, in order to realize at the court of Dionysius the Younger his ideas with regard to political government. The young despot welcomed him warmly, but soon grew tired of serious discussion. On his return to Athens Plato resumed his teaching. He died in his 81st year. He was called the «divine» on account of the depth and originality of his thoughts as well as the beauty of his expositions.

Plato’s writings consist of a collection of thirty-five dialogues and a number of letters. The question as to their genuineness has received various answers, from the conservativism of Grote, who accepts all the dialogues as Plato’s which bear his name, to the radicalism of Schaarsmidt, who accepts nine only as genuine. It is noteworthy that Aristotle directly alludes to nine,—The Republic, The Laws, Timaeus, Phaedo, Symposium, Phaedrus, Gorgias, Theaetetus and Philebus; and to these we may add as beyond doubt the so-called youthful writings, The Apology, Crito, Euthydemus, Laches, Lysis and Protagoras. Others like the Parmenides, Sophist, Politics, if not by Plato, are the works of his immediate pupils.

The question as to the order of composition is one of the vexed problems of Platonic criticism. As there is a Homeric problem, so there is a Platonic problem which has been widely discussed and has produced an inexhaustible literature. Schleiermacher, who was the first in modern times to investigate the subject, regards the works of Plato as the development of a philosophical plan. Hermann, on the other hand, sees in Plato’s writings the disclosure of the various phases of his own mental history. Monk unites these views and sees, especially in the successive dialogues of Plato, an idealistic unfolding of the ideas of Socrates. More recently the attempt has been made to determine the order of the works by linguistic considerations and particular historical circumstances, irrespective of the doctrines taught. Various reasons may have actuated Plato to adopt the style of dialogue. For one thing, it was the only way in which he could give a just idea of the Socratic method. Moreover, it permitted the truth to develop of itself without the appearance of dogmatism, and helped to stimulate the independent thought of the readers. But, above all, it was a form particularly adapted to an artistic nature. Philosophy with Plato was not merely a doctrine, but a life—a power embodied in the personality of the thinker. After the barren abstractions of the earlier philosophers the dialogues of Plato must have been hailed by the Athenian world as a refreshing literary entertainment.

Plato is not only thinker, but artist as well. The dialogues are works of art which set before us in vivid dramatic colouring his thoughts of things and men. They are descriptive, dramatic, historical, by turns: pathos, humour, seriousness, follow each other like the light and shadow of a spring morning. The variety, the sparkle and vivacity, the charming descriptions and subtle sketches of character, the sarcasm and play of humour, above all the purity and grace of diction of his writing, have rendered the name of Plato immortal as one of the greatest masters of literary composition and dramatic style the world has produced.

The speakers in the dialogues are not more historical than the characters of Shakespeare. In nearly every dialogue Socrates is the central figure. Never once does the author speak in his own person. Yet he appears in all his characters. He is, as Grote has said, «Sceptic, dogmatist, religious mystic, mathematical philosopher, artist, poet—all in one, or at least all in succession, during the fifty years of his philosophical life.»

There is one peculiarity in Plato’s dialogues which, while it adds to their charm, increases the difficulty of exact interpretation. It is the frequent use of myths or poetic pictures in which Plato often enshrines his truths. We must remember that he had to contend with the difficulties of language in order to express the novelty of his thought, and, in order to make himself intelligible to ordinary minds, he resorted to the forms of mythology. It may be also that he sought in this way to conceal his religious opinions and escape the criticism of the shallow. Many of the myths are mere allegories. We must not therefore be deceived by the symbolism of Plato or mistake the figure of speech for the literal truth.

It will be impossible to give a detailed account of Plato’s dialogues. It may be said that they declare in some measure the phases of his inner development, and they may be arranged roughly, for convenience, into three groups—the Socratic or early, the Megaric or mature, the Pythagorean or later dialogues.

1. The Socratic or youthful writings, in which Plato argues in Socratic style against the superficiality and the inconsequence of the Sophists.

Charmedes discusses temperance; Lysis, friendship; Laches, fortitude; Hippias Minor, voluntary wrongdoing; First Alcibiades, qualities of statesmanship; Protagoras, the method and influence of the Sophists, together with the Socratic idea of virtue; Gorgias, the sophistical identification of virtue and pleasure, affirming the absoluteness of the good and its superiority to the merely useful and pleasurable.

2. The Megaric dialogues, which are poetic in form and somewhat obscure in language. These deal with the formation of the ideal theory and the ultimate grounds of knowledge.

The Theaetetus stands at the head of this group. It seeks to prove that ideas are objectively real and independent of sensuous perception. They are the sources of all thought—the universal notions from which all knowledge and action are derived.

The Sophist deals with the reciprocal relations of ideas; Parmenides with the relation of ideas to the world of appearances.

3. The Pythagorean group, in which Plato applies the doctrine of ideas to psychology, ethics and natural science. Plato returned from his travels with his mind enriched with facts and ideals which he had gathered. This group is specially characterized by the idealizing of the personality of Socrates, who became the mouthpiece of his views, and by the influence of the Pythagorean philosophy, which gave to the writings of this period a mystical tendency.

The prominent thought of this group is that ideas are objective realities, the ground of all truth, while the phenomena of the senses are but copies of them.

Phaedrus and the Banquet seek to show that the ἔρως (devotion to the idea) alone affords the stability of a scientific principle and secures us from arbitrariness and prejudice in thinking.

Phaedo bases the immortality of the soul on the ideal theory. Philebus applies the highest principles to the notions of pleasure and the supreme good. Timaeus treats of nature and the physical world. Finally, the Republic, begun early and completed in successive strata, extending into the last years of the philosopher’s life, determines the true character of the State and in general affords the grandest impression of his system as a whole.

Plato himself has given us no systematic exposition of his philosophy, and if we follow Aristotle in classifying his thoughts under the three heads—logic, physics and ethics—it must be remembered that Plato does not himself so divide his philosophy.

1. Dialectic or logic. The conversations of Socrates gave to Plato his method of philosophy. Dialectic means originally discussion, conversation. It is therefore the art of developing knowledge by conversation (Republic), or in so far as speech and thought are indistinguishable, the science of properly uniting and separating ideas.

But in a more general sense it is the science of ideas, of the absolute truth of things.

We have seen that the inductive method was ascribed to Socrates, by which he proceeded from the particular to the general. When people spoke of persons or acts being just or beautiful, Socrates asked, What is justice? What is beauty? and tested every definition by a number of particular instances. This in general is the procedure of Plato, but in the Theaetetus he asks at once the deeper question—What is knowledge? He proves that it is not sensation, as Protagoras suggests, for that alone gives no objective certainty true for everyone. Nor is it opinion, which may be true, but has no certainty. A man can only be said to know when he has got at the reason or causes of things; when he sees facts not in their isolation, but in their relation and unity. The question, therefore, which Plato asks is, What is the permanent and universal which underlies all that is variable and particular?

The answer to this question Plato develops in his Theory of Ideas. This is the very kernel of the philosophy of Plato on which, indeed, his whole system is based. Hence it is desirable that we should form a clear conception of what Plato means by ideas. By this theory Plato reconciles the opposing views of Heraclitus and the Eleatics. According to Plato both the one and the many, the permanent and the variable, have their place in the universe : the former in the world of ideas, the latter in the world of sense.

There is a threefold inquiry with regard to Plato’s ideas which may be considered: Concerning (1) their origin, (2) their nature and (3) their relation and unity.

(1) The origin of Ideas. Perhaps we shall more clearly understand how Plato was led to the formation of his theory if we start from the passage in which Aristotle describes the genesis of Plato’s doctrine. According to Aristotle, Plato’s theory arose out of a union of the Socratic concept and the Heraclitean notion of flux. Plato agreed with Heraclitus in holding that all things are ceaselessly flowing, and are therefore incapable of being known. At the same time, he agreed with Socrates as to the importance he attached to universal notions with which definitions are concerned. But he asked, What is this universal or constant element which the general term seeks to express? It cannot be something perceptible, for perceptibles are never constant. But just because it is something permanent and universal, it must be something separable from sensible things. It must have a reality of its own. In this way Plato arrived at the doctrine of ideas, which are simply the objective correlates of our general notions. In the view of Aristotle, Plato accepts Heraclitus’ doctrine of flux as far as the visible world is concerned, while at the same time he does justice to the Eleatic principle by elevating the Socratic general concepts into certain incorporeal and unchanging realities, which he calls ideas. The first point which Aristotle makes clear is that Plato hypostatized the Socratic universals, giving to them not merely a conceptual but a substantial existence on their own account: and, in the second place, he shows that, according to Plato, the ideas are at once transcendent and immanent, at once separate from and yet present in particulars. The idea is, as Plato says, present in the phenomena which bear its name, but at the same time it exists as a separate entity for and by itself.

(2) The nature of the ideas. Such being the origin of Plato’s theory, we are now in a position to look a little more closely at its nature. The ideas are not simply general names or thoughts of the mind, as Socrates had conceived them. They represent realities. They are to our notions what natural objects are to our sense-perceptions. They are alone pure being, the essence of things with the search of which all knowledge begins. The object of all true knowledge is the ideas. They are the only permanent and universal—that indeed from which all particulars are derived. They exist wherever a general notion exists. For example, when you see a chair or a bed there must exist a general idea of chair or bed which is separate from that which you see, and lies behind the particular instance you are looking at. Every object we behold is simply an instance—an instance of something. That something is the idea. The instance is the particular, the idea is the universal, but it is just because the universal is real that the particular has any significance. The general ideas, expressed by our concepts,—’Good,’ ‘Being,’ ‘Identity,’ ‘Man,’—are therefore realities. The ordinary man considers general ideas as but abstractions of the mind, or mental copies of sensible things. The reverse is true. It is the ideas which are the models or originals, and the particular things are but the copies. All we can say of the sensible object is that it has something of what the idea is. Every beautiful object, be it man or statue, or deed, is doomed to destruction. But beauty itself is imperishable, and is more real than all the things which common opinion calls beautiful. In the conceptions of mathematics, which, as Plato says, is the first preliminary training in passing from the life of the senses to a higher intellectual knowledge, we have a clue to the understanding of Plato’s theory of ideas. The mathematician looks at a triangle, but he speaks not of this or that triangle, but of the triangle—the idea of the triangle— the prototype of all particular triangles. In short, we can only know a thing in so far as we have grasped, as a reality, the idea of it—the universal element which manifests itself in the particular.

While it will thus be seen that Plato separates the intelligible from the sensible world, it must not be imagined that the world of ideas is a mere negative of the sensible world. The ideal world is, on the contrary, more real than the phenomenal world—since things are but copies of ideas and obtain what reality they possess from participation in them.

There are three attributes which Plato assigns to ideas, the examination of which may make their nature clearer. In the first place, each idea is one and not many. There cannot, for example, be two ideas of the beautiful, otherwise we should have to postulate a still higher idea to account for the common element in these two, which would be the really existent beautiful. Again, ideas are changeless and eternal. On this characteristic of the ideal world Plato never wearies of insisting. The idea always is. It never becomes. Although particulars come into being and pass away it is uncreated, ever-existent and imperishable. It is in this kingdom that cannot be shaken alone that we can find rest amid the change and decay of terrestrial things. The third attribute of the ideas is their perfection. The idea is thus the absolute standard for the particular group of things which partake of its nature. There is even a perfect bed, a perfect table at which the carpenter looks when manufacturing the particular beds and tables which we use. The manufactured object is always imperfect—it never fully is what it would fain be. So everywhere in nature, and in art, and in all the efforts of man, the ideal type is there, but it is never wholly realized. As Tennyson has expressed it:

«That type of Perfect in his mind
        In Nature can he nowhere find.»

It is this vision of a transcendent standard of beauty which has fired the imagination of artists, and was, in particular, the inspiring motive of the art of Michael Angelo, in whose lifetime the famous academy at Florence made Platonism live again.

(3) Their relation and unity. These three attributes of the ideas—their unity, unchangeableness and perfection— may enable us to understand the motive which led Plato to separate his ideas from the region of sense and assign to them a transcendent existence of their own. In the world of space and time there is nothing but multiplicity, nothing that abides, or that is perfect of its kind. Yet earthly things are always pointing to their ideals and suggesting by their very fragmentariness and imperfections their purer archetypes, of which they are but manifestations. The ideas abide in the heavenly sphere, where the gods and the souls of the pure contemplate them. Not only then are the ideas eternal, but they constitute a world apart from the world of earthly existence. They form a hierarchy among themselves, as Aristotle tells us. Just as in our visible world there is a gradation of beings, from the most imperfect creature to the most perfect, so in the world of ideas there is a progressive advance from lower to higher until the highest is reached—which is the Good. This idea is the unifying principle of all the ideas and the cope-stone of Plato’s entire philosophy. The ideas therefore are at once individual and members of a higher unity. They form an organism and live a common life. It is true Plato sometimes speaks of the heavens as their abode. But this heaven is not a part of the physical universe. The home of the ideas is a place suitable to the nature of the ideas. The idea of the Good is king of the intelligible world, as the sun is of the visible. Just as in the material world the sun gives light and life to every part of it, so in the world of ideas, the idea of the Good is the life of all the other ideas, causing them at once to be and to be known. The Good is therefore the ultimate cause of knowledge; it is the light by which all ideas are seen and known. It is also the ultimate cause of Being, for just as the sun gives generative increase and nourishment to all objects of sense, so the Good furnishes the objects of knowledge, not merely with the power of being known, but with existence itself. In short, the idea of the Good is the source of all subordinate ideas, each of which is but a special adumbration of itself. But if the idea of the Good is absolute, what is God, to whom Plato so often refers? The Good is nothing else than God Himself. If we deny the identity, as is sometimes done, we must maintain that there are two separate principles in the universe: or that one of these is subordinate to the other. But in view of the many passages in the dialogues, notably in the Timaeus and the Republic, which imply the identity, this is hardly possible. Of the Good we read that «it is the best among things that are.» It is «the beginning or source of the universe,» the creator or parent of the visible sun, and through it of the world we live in. In like manner God is spoken of as «the Maker and Father of all»—as the creator and sole cause of whatever is good and beautiful and right in the world. Nor must it be assumed that this highest Being is a mere abstract, impersonal principle, as the conception of the Good would seem to imply. In the dialogues the idea is frequently personified. It is spoken of as Father and King. Though it would not be admissible to attribute to Plato all the clear and definite notions of personality and conscious life which later ages associate with the idea of God; still, as the Good is regarded as the supreme creative principle, alike in the world of sense and the world of thought, it is not going too far to say that Plato conceived of it as possessing intelligent life,—that nous or reason which communicates being and movement to all that lives.

But now the question arises, How do we human beings know the ideas ? What is their relation to our minds ? They are not due to experience. They are not attained by perception or sensation. Yet in all our thinking ideas are involved—we cannot pass from a particular object to a general without having recourse to ideas. It is sometimes maintained that the Platonic ideas exist only in the mind of man, but this is a notion which cannot be legitimately held, in view of Plato’s frequent insistence on their separate and independent existence. All that comes into our minds, or rather that is developed in our minds, is simply our concepts, which, like sensible things, are but shadowy copies of the eternal ideas. At the same time there is a sense in which it may be said that human beings share in these ideas. Plato was evidently convinced that while the infinite was above and beyond the finite, it was at the same time present in the finite—immanent in the souls of men. In proof of this we have but to recall the famous passage in the Phaedo, in which Socrates describes his intellectual development. After describing how he had found no satisfaction in the study of mere secondary causes, he proceeds : «Let me now try to show you what kind of cause interests me… I begin with the ideas, postulating a self-existent Beautiful, Good, Great, and so on. If you grant me these, I hope to make you understand what I mean by causation… I hold that if a thing is beautiful, it is so for no other reason than because it partakes in the Ideal Beauty… I cleave fast in my own mind that nothing makes an object beautiful except the presence of Ideal Beauty, or their communion with each other, or the advent of the idea in whatsoever way. Upon the mode of connection I do not insist: but only that it is the idea of beauty by which beautifuls are made beautiful.» In the same way elsewhere Plato represents the rational faculty, the Soul, as the divine element in man. So that there is a sense in which it may be said that the ideas are not only entities beyond but also within man.

The absolute idea, and with it all other ideas, may be regarded as original endowments of the mind. But they are at first latent, and we are not conscious of them. The aim and art of all true education lie in drawing forth from the pupil’s own mind its own native treasures and awaking those seeds of knowledge which have pre-existed in the soul awaiting full growth and development.

To account for the origin of those germs of truth in the mind Plato falls back on the mythical tradition that the soul in a previous state beheld these ideas, and that knowledge of them is possible because the mind by an act of memory or recollection recovers what is its own. According to Plato true philosophic knowledge is nothing more than recollection. Reasoning is the only road to truth. The art of dialectic,—the intellectual midwifery of Socrates —is necessary to help the soul to bring forth genuine thoughts. The slave-boy in the Meno, who manages to prove a simple geometrical proposition, is helped step by step by the questions of Socrates, who only brings out what was already in the lad’s mind and enables him to recover the missing whole, of which at first he sees only fragments. Sensations provoke ideas: they do not create them. Their function is to recall to our minds our latent possessions. The perception of corporeal things calls the remembrance back to these forgotten forms and awakens the philosophic impulse—the love of ideas, by which the soul is raised again to the knowledge of the true reality. The homesick soul, living in exile in the world of sense, longs to be reunited with the absolute, and to see again those truths which it once knew. In the seventh book of the Republic Plato gives us his celebrated similitude, by which he allegorizes the conversion of the mind from the world of sense to the world of ideas. The majority of men are pictured by him as prisoners in a subterranean cavern, which opens to the day by a long, wide passage; they are chained with their backs to a fire looking at the shadows, thrown by it on the wall, of men and other figures which pass behind them. These captives represent the condition of men who see nothing but the shadows of realities. If one of these prisoners should be loosed from his bonds and made to turn round and walk towards the light, at first he would be dazzled by the glare and unable to see clearly, but by and by he would realize that what he previously took for realities were nonentities; and, if he were brought up out of the cavern into the light of day, he would soon be aware of the real objects and know that what he had previously beheld in the cave were only shadows, illusions. Remembering his previous state in the cavern, he would pity those who were still within it. All this—the turning round, the toilsome ascent out of the cave, the gradual accustoming of his eyes to the light, the ultimate realization of the objects as they are in themselves—represents the education of the philosopher. Education, in other words, is «the turning round of the eyes of the soul.»

2. The physics of Plato is chiefly confined to the Timaeus. He gives a rough draft or sketch of the philosophy of nature for which he does not claim certainty. He seeks to explain occurrences and phenomena of nature from the point of view of the world’s purpose or end.

The neo-Platonists regarded the Timaeus as the most important of Plato’s works. In Raphael’s «School of Athens» Plato is represented with the Timaeus in his hand, and, as has been said, no writing of Plato exercised so powerful an influence on subsequent Greek thought. It must be remembered, however, that Plato himself did not attach supreme importance to this book, and the elaboration of a theory of the physical universe he regarded as but a recreation from severer meditation. In his astronomical views Plato was a child of his age, and though he anticipates many ideas of later times with regard to the movement of the stars and the structure of animal bodies, he had not Aristotle’s eager interest in physical matters. As the details of Plato’s cosmology belong rather to the history of natural science than philosophy, it will not be necessary to dwell at any length upon them.

While his teleological view of nature is given in mythical form only, he takes up a position sharply opposed to the mechanical explanation of the world suggested by Democritus. In opposition to the theory that this world is the result of the accidental or undesigned meeting of lawless particles, coming into existence just to perish again, he sets forth his theory that there is only this one world, a most perfect and most beautiful cosmos, unitary in nature and unique in kind, and that its origin can be traced only to a reason acting according to ends.

It may be said that he had no doubt as to the ultimate unity of the universe «which is one and only begotten.» The whole of nature is a revelation of the good. The world is a divine child, «the image of its maker—most mighty and good, most beautiful and perfect.» «Let me tell you why the Creator made this world of generation. He was good, and the good can never have any jealousy of anything. And being without jealousy, he desired that all things should be as like unto Himself as possible… For God desiring that all things should be good, and that, so far as might be, there should be nothing evil, having received all that is visible, not at rest but moving in a disorderly and irregular fashion, brought it from disorder into order… As intelligence could not be present in anything that was devoid of soul, when he was forming the universe he put intelligence in soul, and soul in body, that he might be the maker of a work that was by nature fairest and best. Wherefore, using the language of probability, we may say that the universe became a living creature, in very truth possessing soul and reason by the providence of God.»

The world is an emanation of the world-forming God (δημιουργός). The actual cosmos is the image of God which was originally shaped out of the idea, or ideas, and the formless chaotic mass—an indefinite plasticity, which takes up all corporeal forms into itself. It is significant that Plato, like the earlier philosophers, gets no further back than this formless void or non-being, which he assumes as existing before all else. This primitive material contains the element of evil or imperfection; hence the world, though an emanation of God, cannot be perfect. The main interest of Plato’s cosmogony lies in the conception that the world is the product and image of reason—an organism of harmony and order.

3. Plato’s Ethics is based on his doctrine of the soul, which is the first attempt in philosophy to understand the psychical life from within, and is central to the whole system.
The soul springs from the ideal world and discloses its origin in its yearning for the beautiful and its effort to gain the mastery over the physical part of man’s nature.

Plato describes the soul of man as a threefold being— a man, a lion and a many-headed hydra: or as a charioteer driving two horses, one of a noble and the other of an ignoble nature. The noble element is striving continually to mount to the region of the heavens, where it may behold the images of divine beauty and wisdom which are proper to its nature; but the baser element, which is the body, is ever dragging the soul down to the earth.

In itself the soul is indestructible and divine, but through its union with the body it participates in the fluctuations of the sensuous nature and is subject to the influence of the physical. Hence it may be said to belong to two worlds, of both of which it bears the traits. In its essence, there \s that which corresponds to the world of ideas, and that which corresponds to the world of perception. The former is the rational nature (νοῡς), the seat of knowledge and of virtue. The latter, the irrational nature, Plato further divides into two elements—the nobler, which inclines towards reason, and the lower, which resists it. The nobler is the will or spirit (θύμος); the lower, the sensuous desire (ἐπιθυμία). Hence, Reason, Spirit, and Appetite, are the three activities of the soul. The rational element alone, which is the soul in its true being, apart from its mixture with the body, is that which is immortal. It possesses a vitality which survives all change. The proof of the immortality of the soul Plato sets forth chiefly in the Phaedo, though he refers to the subject also in other dialogues.

Various arguments are adduced by Plato which have been elaborated by philosophers in later times. He argues the soul’s immortality (1) from its simplicity, which renders all decomposition impossible; (2) from the goodness of the creator; and (3) from the fact that it is the very principle of life, and therefore that a transition from being to non-being is impossible; and (4) from the longing of the wise man to be freed from the fetters of the body and come into direct communion with the world of ideas. It has been urged by some modern critics that Plato’s arguments do not prove the immortality of the soul at all in the sense of continued personal existence. All that he shows is, it is alleged, that the soul or mind belongs to the eternal world, and not to the world of appearance merely. Yet the doctrine of «Recollection,» when stripped of its poetic form, does imply a kind of unity of self, and a continuance of personal existence, at least before this life. And, moreover, it must be noticed that, whatever we may think of his attempted proofs, the conclusion which he seeks to draw from them all, in the Phaedo and elsewhere, has reference to the individual soul. «According to Plato,» says the late Mr. Adam, «the true and essential ‘ego’ is the rational and spiritual part of our nature, which he calls Nous: and he would consequently hold that we do not lose, but rather gain, our perfect individuality by union with the all-embracing, all-sustaining mind or spirit in which even now we live and move and have our being.»

Upon this conception of the soul, Plato bases the moral destiny of the individual. The fettering of the soul to the body is at once a consequence and punishment of the sensuous appetite. The soul exists before the earthly life as well as after, and the sin in which the soul is ensnared in the world of sense has been committed in a pre-existent state, and its destiny hereafter will depend upon how far it has freed itself from appetite, and turned to the knowledge of ideas.

Plato teaches the Pythagorean doctrine of transmigration after death. The souls of men go to the place of reward or punishment, and after one thousand years they are permitted to choose a new lot of life. He who has thrice chosen the higher life gains, after three thousand years, the home of the gods in the kingdom of thought. Others wander for thousands of years in various bodies, and many are destined to pursue their earthly life in lower and ever lower animal forms.

The supreme aim of the soul is to break the power of evil and attain to freedom and wisdom and goodness. Plato seems to waver in his teaching as to the way in which the higher life is to be reached. Sometimes he would seem to teach a negative ascetic morality of suppression of all appetite, and flight from the world of sense. But in other places he implies that the life of wisdom and goodness can be realized even in this world of sense. This world is full of joy and beauty, and by a life of well-ordered harmony it is to be used and not abused. The passions and appetites, in so far as they are elements of the soul, have their justification, and are, therefore, not to be wholly quenched, but transmuted and transformed into channels of the higher life.

In accordance with this idea, in the Republic he shows that each part of the soul has a definite task to fulfil, and a perfection of its own to reach. All virtue is indeed one, but it may be divided into four cardinal virtues—wisdom, courage, temperance, justice. The virtue of reason is wisdom (σοφία): the virtue of the spirit or heart is courage (άνδρία): the virtue of sensuous appetite is moderation, self-control (σωφροσύνη).

But in addition to all these, the virtue of the soul as a whole, which binds all the other virtues together and preserves them in a perfect relationship, is justice, integrity (δικαιοσύνη).

Righteousness as the unity of the virtues consists in each part in the individual and in society, doing its proper work, and not interfering with the work of others.

Pleasures are distinguished in kind and degree of excellence according to the part of the soul which they accompany, and the pleasures of the highest part must be preferred to those of lower parts, because the higher part, the reason, is the only part capable of judging. Pleasure cannot be the chief good, as the Cyrenaics hold, for it partakes of the nature of the indefinite: but neither is knowledge alone the chief good. The best life must contain both. «Plato’s more important ethical dialogues, beginning with the Protagoras and ending with the Philebus, make a steady advance from the ethics of Socrates,»and prepare the way for the more complete «codification» of Aristotle.

Plato’s doctrine of the soul leads, naturally, to his theory of the State, to a consideration of which the Republic is devoted. The tendency of the doctrine of ideas, directed as it is to the general and universal, attains its completion, not in the individual, but in the species. The ethical ideal becomes for Plato the political. At a time when there were everywhere visible the signs of the dissolution of Greek political life, in opposition to the individual theories of happiness which were in vogue, Plato exalts the conception of the State as the ideal of humanity.

The State is indeed the enlarged man. Just as there are three elements in the soul, so there must be corresponding orders in the State—Rulers, Warriors, Workers. Wisdom is the virtue of the rulers and teaching class : courage that of the warriors and guardians (φύλακες), while the virtue of the workers, artisans and the great mass of the people is self-control, obedience. Finally, justice is the virtue and harmony of the whole State.

The main idea of Plato’s Republic is the sacrifice of the individual to the whole,—the subordination of separate interests to the general good. Private property and family life, education, choice of occupation and employment of special gifts, must all be subordinated to the order of the State and dedicated to the advancement of the common weal. All things are to be in common; even the breeding and rearing of citizens are to be entirely under the control of the rulers. The State is to be a single family, a large educational establishment in which the individual only exists for the good of the whole. By means of a constantly repeated process of selection, continued from birth to maturity, the two upper classes are to be continually preserved and reinforced.

Some of the features of Plato’s ideal State were doubtless suggested to him by the Pythagorean brotherhood. But though his general conception is, theoretically, very beautiful and most complete, it is as impracticable as the communistic attempts of modern times. Both tend to suppress individuality and fetter freedom. Plato failed to recognise the worth of man as man, and did not rise above the notion of slavery prevailing in his time. All physical defects were to be banished from the State. Poetry, even, was only to be practised under the supervision of judges; and all dramatic works which misrepresented the human and divine life were to be excluded. Gymnastics and music, mathematics and philosophy, are the means by which the young are to be educated and made strong and fit in body, will and mind.

Plato, as we have seen, is not always quite consistent, for while he sometimes identifies the good and the beautiful and justifies the enjoyment of the good things of life, at other times his teaching is tinged with asceticism, and he preaches abnegation as the path to virtue. But, generally, it may be said that he rises above the cynic contempt for the beauty of the human form and the graces of social intercourse. The body must be carefully disciplined that it may become the fit servant of the soul; and the young are to be brought up amid fair scenes and noble surroundings that they may be prepared for fulfilling the highest ends of service.

Before leaving Plato, it may be well to attempt to sum up the merits and defects of his position. For Plato is one of the immortal teachers of mankind whom we can never get past, and whose errors are more suggestive and instructive than many another’s truths.

The first great truth for which we are indebted to him is that, in order to direct human knowledge to its proper goal in the interpretation of the nature of things, we must start with knowledge itself—from the peculiar gift of reason which has been allotted to man. The «know thyself» of Socrates became for his great disciple the master-key which was to unlock the mystery of being. It is Plato’s merit to have been the first to attempt a theory of knowledge. In reaction against the materialism of the Sophists he followed Socrates in emphasizing human reason as the source of all truth—as the one durable and persistent element amid all that was changeable and evanescent. «We could not take for granted even the possibility of knowledge,» says Socrates in Cratylos, «if everything were changing and had no permanence.» The rational principle in man is characterized by the possession of the universal ideas—the good, the beautiful, the true. These ideas are recognisable everywhere as the peculiar property of reason.

The second great truth for which we are indebted to Plato is, that all our thinking is accomplished by means of universal conceptions, which are contrasted with both material things and sensible perceptions. These general ideas are the true object of rational thought, and in them the reason discerns the permanent and essential amid the changing stream of phenomena. This great truth, the doctrine of abstract or universal ideas, has powerfully influenced the after history of philosophy. It was the truth of which even Locke had some dim intuition, and which, since Kant’s time, has come to be so important a factor in every system of knowledge.

But while the Platonic doctrine of ideas has been the fruitful source of all that is valuable in the philosophy of the mind, in Plato’s treatment, the theory is entangled with ontological assumptions, which split his whole conception of the world into a dualism. On the one side he conceives of the soul as an immaterial substance to which alone pure thought belongs. On the other side he places the material world with its perpetual flux and change. Only what the reason apprehends, viz., the universal ideas, are real and true. All else, particular and individual things, are seeming and evanescent. The ideas are the eternal prototypes of things which, by reason of the phenomenal world in which we live, we can only dimly perceive. The true way, therefore, to attain to knowledge is to disentangle the ideas from their material relations, and to rise by abstraction and self-denial above the world of sense into the purer region of thought. The imprisoned soul must be emancipated from the body. In a former state of existence the spirit dwelt with the gods in the realm of ideas. The soul comes into this world with a reminiscence of its former glory, which, however, earthly things tend to obscure and obliterate. All true knowledge is really recollection. To bring that recollection to clearness and to purify the vision of the soul by the crucifixion of earthly desires is the aim and ideal of the wise man’s life.

It will thus be seen that the natural tendency of Plato’s philosophy is to disparage the world of sense and to regard the earthly life as a clog to the aspirations of the soul.

This dualism of Plato between the world of ideas and the world of phenomena, between the life of knowledge and the life of sense, has become the crux of modern philosophy. How are we to reconcile these two sides? Plato’s plan is to allow the phenomena to become absorbed in the ideas while the material world is banished into the realm of the non-existent, and the life of purity is attained by denying the legitimacy of the senses. But this is an avoidance of the difficulty, not a solution of it. It is the attainment of unity only by suppression of one of the terms of opposition. It might be asked, as indeed Plato himself sometimes sees, why were the desires and passions bestowed upon us if they are only hindrances to the spirit and have no legitimate function to serve? What can be the rationale of a world of phenomena if it is only there to be got rid of?

It must not be supposed that Plato did not see these difficulties, and in his later dialogues, particularly in the Timaeus and the Laws, there are those who hold that he sought to recast his theory and eliminate the dualism of his earlier position. But if the introduction of the Demiurge or second principle who forms the world be the work of his later life, it does not remove but increases the duality. The Laws, on the other hand, but repeat much of the social philosophy of the Republic, but in a more prosaic manner.» He who,» says Jowett, «was the last of the poets, in his book of Laws wrote prose only: he has himself fallen under the rhetorical influences which in his earlier dialogues he was combating.»

When all is said, we must recognise the theory of ideas as Plato’s distinctive glory. Not only is it the basis on which the whole superstructure of his philosophy rests, but it is the foundation on which all subsequent idealists have reared their interpretation of the world. Whatever we may think of his system as a whole and however we may criticise its details, no adverse judgment can detract from the preeminence of Plato among the masters of thought in all ages. All that is fruitful in later speculation has its seeds in his philosophy. It was his to exalt the power of the mind, and he has shown that its influence embraces not ethics and dialectics alone, but elucidates politics, art, and religion. He has based physical science on a knowledge of mathematics and established a method of research which has continued ever since. He has sketched the outlines of a new religion—a religion of monotheism, of humanity, of purity and immortal life, substituting the intelligent imitation of God for the blind and superstitious observance of his will. Not only do his dialogues disclose a charm of manner and style of literary composition which has never been surpassed, but they breathe a spirit which raises us above the world of sense into a region of exalted types and noble ideals. Raphael in his immortal picture represents Plato as pointing towards heaven. It was the aim of his life and thought to show that all reality and knowledge are to be sought not in this world of change and decay, but in that realm of purity beyond the skies, where God in his unchangeable perfection dwells.

The genius of Plato is always reaching forth to eternal things—as Goethe says—»every utterance of Plato points to ‘ein ewig Ganzes’—an eternal principle of Goodness, Truth and Beauty, which he strives to quicken in every bosom.» In his description in the Phaedus of the scene in the prison-house of Athens—one of the most touching in history—there occur these fine words: «Nay, Socrates, I think the sun is still upon the mountains, and has not yet set.»

In Plato, then, philosophy is placed in an idealistic antithesis to actuality, and it therefore requires for its completion a more realistic conception of things. This, as we shall see, was supplied by Aristotle, the greatest of Plato’s disciples.