), the philosopher.
I. Life of Plato.
The spirit of Plato is expressed in his works in a manner the more lively aid personal in proportion to the intimacy with which art and science are blended in them. And yet of the history of his life and education we have only very unsatisfactory accounts.
He mentions his own name only twice (Phaedon,
p. 59b., Apolog.
p. 58b.), and then it is for the purpose of indicating the close relation in which he stood to Socrates; and, in passing, he speaks of his brothers, Adeimantus and Glaucon, as sons of Ariston (de Rep.
i. p. 327, comp. Xenoph. Mem.
3.6; D. L. 3.4
The writer of the dialogues retires completely behind Socrates, who conducts the investigations in them. Moreover Plato's friends and disciples, as Speusippus in his eulogiunm (D. L. 3.2
, with the note of Menage; Plut. Quaest. Sympos.
8.2, &c.), appear to have communicated only some few biographical particulars respecting their great teacher; and Alexandrian scholars seem to have filled up these accounts from sources which are, to a great extent, untrustworthy. Even Aristoxenus, the disciple of Aristotle, must have proceeded in a very careless manner in his notices respecting Plato, when he made him take part in the battles at Tanagra, B. C. 426, and Delium, B. C. 424. (D. L. 3.8
; comp. Aelian, Ael. VH 2.30
Plato is said to have been the son of Ariston and Perictione or Potone, and to have been born at Athens on the 7th day of the month Thargelion (21st May), Ol. 87. 2, B. C. 430; or, according to the statement of Apollodorus, which we find confirmed in various ways, in Ol. 88. 1, B. C. 428, that is, in the (Olympic) year in which Pericles died; according to others, he was born in the neighbouring island of Aegina. (D. L. 3.1
comp. 5.9, 3.2, 3; Corsini, Fast. Attici,
3.230; Clinton, Fasti Hell.
sub anno 429, &c.) His paternal family boasted of being descended from Codrus; his maternal ancestors of a relationship with Solon (D. L. 3.1
.) Plato mentions the relationship of Critias, his maternal uncle, with Solon. (Charm.
p. 155, 159. Comp. Tim.
20.) Originally, we are told, he was named after his grandfather Aristocles, but in consequence of the fluency of his speech, or, as others have it, the breadth of his chest, he acquired that name under which alone we know him. (D. L. 3.4
; Vita Platonis,
p. 6b; Tychsen, Bibliothek der allen Literatur und Kunst,
According to one story, of which Speusippus (see above) had already made mention, he was the son of Apollo; another related that bees settled upon the lips of the sleeping child. (Cic. de Divin.
He is also said to have contended, when a youth, in thle Isthmian and other games, as well as to have made attempts in epic, lyric, and dithyrambic poetry, and not to have devoted himself to philosophy till later, probably after Socrates had drawn him within the magic circle of his influence. (Diog. Laetrt. 3.4, 5; Ael. VH 2.30
; Plat. Epist.
vi.) His love for Polymnia had brightened into love for the muse Urania (Plat. Symp.
187). Plato was instructed in grammar, music, and gymnastics by the most distinguished teachers of that time. (D. L. 3.4
; comp. Hermann, Geschichte und System des Platonischen Systems,
p. 98, note 48, p. 99, note 49.)
At an early age (ἐκ νέου
) he had become acquainted, through Cratylus, with the doctrines of Heracleitus (Arist. Metaph.
1.6 ; comp. Appuleius, de Doctr. Plat.
p. 47. Elm.) ; through other instructors, or by means of writings, with the philosophical dogmas of the Eleatics and of Anaxagoras 2
(Diog. Laert. l.c.; Vita Anon.
ap. Tychsen, p. 13); and what is related in the Phaedo and Parmenides of the philosophical studies of the young Socrates, may in part be referable to Plato.
In his 20th year he is said to have betaken himself to Socrates, and from that time onwards to have devoted himself to philosophy. (D. L. 3.6
; Suidas s. v.
makes this into an intercourse of twenty years' duration with Socrates.)
The intimacy of this relation is attested, better than bv hearsay accounts and insufficient testimonies (D. L. 3.5
; Paus. 1.30.3
, &c.; Xen. Mem. 3.6.1
), by the enthusiastic love with which Plato not only exhibits Socrates tis he lived and died--in the Banquet and the Phaedo,--but also glorifies him by making him the leader of the investigations in the greater part of his dialogues; not as though he had thought himself secure of the assent of Socrates to all the conclusions and developments which he had himself drawn from the few though pregnant principles of his teacher, but in order to express his convictiont that he had organically developed the restults involved in the Socratic doctrine.
It is therefore probable enough that, as Plutarch relates (Marius,
46; comp. Lactant. Div. Inst.
3.19.17), at the close of his life he praised that dispensation which had made him a contemporary of Socrates.
After the death of the latter he betook himself, with others of the Socratics, as Hermodorus had related, in order to avoid threatened persecutions (D. L. 2.106
), to Eucleides at Megara, who of all his contemporaries had the nearest mental affinity with him. That Plato during his residence in Megara composed several of his dialogues, especially those of a dialectical character, is probable enough, though there is no direct evidence on the subject (Ast, vom Leben und den Scrifien des Plato,
p. 51; Van Heusde, Init. Plat. doct.
i. p. 72; Hermann, ibid.
pp. 46, 490).
The communication of the Socratic conversation recorded in the Theaetetus is referred to Eucleides, and the controversial examination, contained in the Soplistes (p. 246) and apparently directed against Eucleides and his school, of the tenets of the friends of certain incorporeal forms (ideas) cognisable by the intellect, testifies esteem for him. Friendship for the mathematician Theodorus (though this indeed does not manifest itself in the way in which the latter is introduced in the Theaetetus) is said to have led Plato next to Cyrene (D. L. 3.6
; Appul. l.c.
). Through his eagerness for knowledge he is said to have been induced to visit Egypt, Sicily, and the Greek cities in Lower Italy (Cic. de Rep.
1.10, de Fin.
5.29; V. Max. 8.7.3
; Vita Anon. l.c.
). Others, in inverted order, make him travel first to Sicily and then to Egypt (Quint. Inst. 1.12.15
; D. L. 3.6
), or from Sicily to Cyrene and Egypt, and then again to Sicily (Appuleius, l.c.
p. 47; comp. Clinton, F. H.
vol. ii. p. 366).
As his companion we find mentioned Eudoxus (Strab. 17.29, in opposition to D. L. 8.87
), or Sitmiias (Plut. de Daem. Socr.
7), or even Euripides, who died Ol. 93. 2 (D. L. 3.6
). More distant journeys of Plato into the interior of Asia, to the Hebrews, Babylonians, and Assyrians, to the Magi and Persians, are mentioned only by writers on whom no reliance can be placed (Clerm. Alex. ad v. Gent.
p. 46; Vita Anon. p. 14 ; comp. D. L. 3.7
; Lactant. Instit.
4.2 ; comp. Cic. Tusc. Disp.
4.19). Even the fruits of his better authenticated journeys cannot be traced in the works of Plato with any definiteness.
He may have enlarged his mathematical and astronomical knowledge, have received some impulses and incitements through personal intercourse with Archytas and other celebrated Pythagoreans of his age (Clem. Alex. Cic. Val. Max. &c. ll. cc.
), have made himself acquainted with Egyptian modes of life and Egyptian wisdom (Plat. de Leg.
ii. p. 656, vii. pp. 799, 819, Phaedo,
p. 274, Philcb.
p. 18, Tim.
21; comp. Epinom.
p. 986); but on the fundamental assumptions of his system, and its development and exposition, these journeys can hardly have exercised any important influence; of any effect produced upon it by the pretended Egyptian wisdom, as is assumed by Plessing (Memnonium,
ii. p. 288, &c., 504, &c.; Versuch zur Aufklärung der Philosophie des altesten Alterthums,
2.2. p. 879, &c.) and others, no traces are to be found (comp. Hermann, l.c.
1.55, &c.). That Plato during his residence in Sicily, through the intervention of Dion, became acquainted with the elder Dionysius, but very soon fell out with the tyrant, is asserted by credible witnesses (especially by Hegesander ap. Ath. 11.116
, p. 507b; Diod. 15.7
; Plut. Dio 4
; D. L. 3.18
. The Platonic epistle vii. pp. 324, 326, 327, mentions only the acquaintance with Dion, not that with the elder Dionysius). More doubt attaches to the story, according to which he was given up by the tyrant to the Spartan ambassador Pollis, by him sold into Aegina, and set at liberty by the Cyrenian Anniceris.
This story is told in very different forms. On the other hand, we find the statement that Plato came to Sicily when about forty years old, so that he would have returned to Athens at the close of the 97th Olympiad (B. C. 389 or 388), about twelve years after the death of Socrates; and perhaps for that reason Ol. 97. 4, was set down by the chronologers whom Eusebius follows as the period when he flourished.
After his return he began to teach, partly in the gymnasium of the Academy and its shady avenues, near the city, between the exterior Cerameicus and the hill Colonus Hippius, partly in his garden, which was situated at Colontis (Timon ap. D. L. 3.7
, comp. 5; Plut. de Exilio,
100.10, &c.). Respecting the acquisition of this garden again, and the circumstances of Plato as regards property generally, we have conflicting accounts (Plut. Diog. Laert. Appul. ll. cc. ;
A. Gell. N. A.
3.17, coump. Hermann, l.c.
p. 77, &c.). Plato taught, gratuitously (D. L. 4.2
; Olympiod. et Anon.), and agreeably to his maxims (Phaed.
p. 275, Protag.
pp. 329, 334, Gorg
p. 449, comp. Hipp. Min.
p. 373), without doubt mainly in the form of lively dialogue; yet on the more difficult parts of his doctrinal system he probably also delivered connected lectures; at least in the accounts of his lectures, noted down by Aristotle and other disciples, on the Good (see below) there appears no trace of the form of dialogue. Themistius also (Orat.
xxi. p. 245d' represents him as delivering a lecture on the Good in the Peiraeeus before an audience which gradually dwindled away.
The more narrow circle of his disciples (the number of them, which can scarcely have remained uniform, is stated at 28) assembled themselves in his garden at common, simple meals (Ath. 1.7
, comp. Aelian, Ael. VH 2.18
; D. L. 2.8
), and it was probably to them alone that the inscription said to have been set up over the vestibule of the house, "let no one enter who is unacquainted with geometry," had reference (Tzetzes, Chiliad.
8.972). From this house came forth his nephew Speusippus, Xenocrates of Chalcedon, Aristotle, Heracleides Ponticus, Hestiaeus of Perinthus, Philippus the Opuntian, and others, men from the most different parts of Greece. To the wider circle of those who, without attaching themselves to the more narrow community of the school, sought instruction and incitement from him, distinguished men of the age, such as Chabrias, Iphicrates (Aristid. ii. p. 325), Timotheus (Ath. 10.14
, comp. Ael. VH 2.18.10
; Plut. de Sanit. tuenda,
p. 127. 6), Phocion, Hyperides, Lycurgus, Isocrates (D. L. 3.46
), are said to have belonged. Whether Demosthenes was of the number is doubtful (Dem. Epist.
v.; Cic. de Orat. 1.20
5, de Offic.
1.1, &c.; on the other hand see Niebuhr, Kleine historische Schriften,
p. 482; Bake, Biblioth. Crit. Nova,
5.1. 194, &c.). Even women are said to have attached themselves to him as his disciples (Diog. Laert. l.c.,
comp. Olympiod.). Plato's occupation as an instructor was twice interrupted by journeys undertaken to Sicily ; first when Dion, probably soon after the death of the elder Dionysius (Ol. 103. 1, B. C. 368), determined him to make the attempt to win the younger Dionysius to philosophy (Plat. Epist.
vii. p. 327, iii. p. 316c; Plut. Dio 100.11
, &100.16, &c., Philosoph. esse cum Princip.
100.4; Corn. Nep. 10.3 ; D. L. 3.21
); the second time, a few years later (about B. C. 361), when the wish of his Pythagorean friends, and the invitation of Dionysius to reconcile the disputes which had broken out shortly after Plato's departure between him and his stepuncle Dion, brought him back to Syracuse. His efforts were both times unsuccessful, and he owed his own safety to nothing but the earnest intercession of Archytas (Plat. Epist.
vii. pp. 339, 345, iii. p. 318; Plut. Dio 100.20
; D. L. 3.25
). Immediately after his return, Dion, whom he found at the Olympic games (Ol. 105. 1, B. C. 360), prepared for the contest, attacked Syracuse, and, supported by Speusippus and other friends of Plato, though not by Plato himself, drove out the tyrant, but was then himself assassinated; upon which Dionysius again made himself master of the government (Plat. Ep. ;
Plut. ll. cc. ; D. L. 3.25
). That Plato cherished the hope of realising through the conversion of Dionysius his idea of a state in the rising city of Syracuse, was a belief pretty generally spread in antiquity (Plut. Philos. e. princ.
100.4; Themist. Oral.
xvii. p. 215b; D. L. 3.21
), and which finds some confirmation in expressions of the philosopher himself, and of the seventh letter, which though spurious is written with the most evident acquaintance with the matters treated of (p. 327e; comp. Hermann, l.c.
p. 66, &c.). If however Plato had suffered himself to be deceived by such a hope, and if, as we are told, he withdrew himself from all participation in the public affairs of Athens, from despair with regard to the destinies of his native city, noble even in her decline, he would indeed have exhibited a blind partiality for a theory which was too far removed from existing institutions, and have at the same time displayed a want of statesmanlike feeling and perception.
He did not comply with the invitations of Cyrene and Megalopolis, which had been newly founded by the Arcadians and Thebans, to arrange their constitution and laws (Plut. ad princ. inerud.
100.1; D. L. 3.23
; Aelian, Ael. VH 2.42
). And in truth the vocation assigned him by God was more that of founding the science of politics by means of moral principles than of practising it in the struggle with existing relations. From the time when he opened the school in the Academy (it was only during his second and third journeys to Sicily that one of his more intimate companions--Heracleides Ponticus is named--had to supply his place, Suid. s. v. Heracleid.
) we find him occupied solely in giving instruction and in the composition of his works.
He is said to have died while writing in the 81st, or according to others the 84th year of his age, in Ol. 108. 1, B. C. 347 (Cic. de Senect.
5; Senec. Epist.
lviii. ; Neanthes in D. L. 3.3
; D. L. 5.9
; Athen. 5.217
According to Hermippus he died at a marriage feast (D. L. 3.3
; August. de Civ. Dei,
8.2). Thence probably arose the title of the éloge of Speusippus--Πλάτωνος περίδειπνον
According to his last will his garden remained the property of the school (D. L. 3.43
), and passed, considerably increased by later additions, into the hands of the Neo-Platonists, who kept as a festival his birth-day as well as that of Socrates (Damasc. ap. Phot. Cod.
ccxlii.; Porphyr. ap. Euseb. Praep. Evang.
10.3, p. 468). Athenians and strangers honoured his memory by monuments (D. L. 3.43
; Phavorin. ib.
25). Yet he had no lack of enemies and enviers, and the attacks which were made upon him with scoffs and ridicule, partly by contemporary comic poets, as Theopompus, Alexis, Cratinus the younger, and others (D. L. 3.26
, &c.; Athen. 11.509
, ii. p. 59), partly by one-sided Socratics, as Antisthenes, Diogenes. and the later Megarics (D. L. 3.35
; comp. Schleiermacher's Platon,
2.1, pp. 19, 1113, 404, 406; 2.2, pp. 17, 20), found a loud echo among Epicureans, Stoics, certain Peripatetics, and later writers eager for detraction. Thus even Antisthenes and Aristoxenus (D. L. 3.35
; Athen. 5.507
, xi. p. 507; Mahne, de Aristoxeno,
pp. 14, 73, 91) charged him with sensuality, avarice, and sycophancy (D. L. 3.29
; Athen. 11.509
c, xiii. p. 589c); and others with vanity, ambition, and envy towards other Socratics (Athen. 11.507
d; D. L. 6.3
; comp. A. Bockh. Commentat. Aead. de Simultate quae Platoni cum Xenophonte intercessisse fertur,
Berol. 1811). Others again accused him of having borrowed the form and substance of his doctrine from earlier philosophers, as Aristippus, Antisthenes (Theopomp. ap. Athen. 11.508
c), Protagoras (D. L. 3.37
), Epicharmus (Alcimus ap. D. L. 3.9
, &c.), Philolaus (D. L. 3.9
But as the latter accusation is refuted both by the contradiction which it carries in itself, and by comparison of the Pythagorean doctrine with that of Plato, so is the former, not only by the weakness of the evidence brought forward in its favour, but still more by the depth and purity of moral sentiment, which, with all the marks of internal truth, is reflected in the writings of Plato.
II. The Writings of Plato.
These writings, by a happy destiny, have come down to us complete, so far as appears, in texts comparatively well preserved, and have always been admired as a model of the union of artistic perfection with philosophical acuteness and depth. Plato was by no means the first to attempt the form of dialogue. Zeno the Eleatic had already written in the form of question and answer (D. L. 3.48
; comp. Arist. Elench. Soph.
10). Alexamenus the Teian and Sophron in the mimes had treated ethical subjects in the form of dialogue (Diog. Laert. l.c. ; Athen. 11.505
b.; Olympiod. p. 78 ; comp. Hermann on Arist. Poet.
p. 93, &c.) Xenophon, Aeschines, Antisthenes, Eucleides, and other Socratics also had made use of the dialogical form (Diog. Laert. passim); but Plato has handied this form not only with greater mastery than any one who preceded him, and, one may add, than any one who has come after him, but, in all probability, with the distinct intention of keeping by this very means true to the admonition of Socrates, not to communicate instruction, but to lead to the spontaneous discovery of it.
The dialogue with him is not merely a favourite method of clothing ideas, handed down from others, as has recently been maintained (Hermann, l.c.
i. p. 354), but the mimetic dramatic form of it is intended, while it excites and enchains the attention of the reader, at the same time to give him the opportunity and enable him to place himself in the peculiar situations of the different interlocutors, and, not without success, with them to seek and find.
But with all the admiration which from the first has been felt for the distinctness and liveliness of the representation, and the richness and depth of the thoughts, it is impossible not to feel the difficulty of rendering to oneself a distinct account of what is designed and accomplished in any particular dialogue, and of its connection with others. And yet again it can hardly be denied that each of the dialogues forms an artistically self-contained whole, and at the same time a link in a chain.
That the dialogues of Plato were from first to last not intended to set before any one distinct assertions, but to place the objects in their opposite points of view (Cic. Ac. 1.12
), could appear credible only to partisans of the more modern sceptical Academy. Men who took a deeper view endeavoured, by separating the different kinds and classes of the dialogues, or by arranging together those which had a more immediate reference to each other, to arrive at a more correct understanding of them.
With reference to the first, some distingllished dramatic, narrative, and mixed dialogues (D. L. 3.50
), others investigating and instructing dialogues, and again such as investigated gymnastically (maieutically or peirastically,) and agonistically (endeictically or anatreptically); as also dialogues which communicated instruction theoretically (physically or logically), and practically (ethically or politically). (D. L. 3.49
; Albin. Isag.
With regard to the second point, attention was especially directed to the dramatic character of the dialogues, and, according to it, the Alexandrian grammarian Aristophanes of Byzantium arranged a part of them together in trilogies (Sophistes, Politicus, Cratylus -- Theaetetus, Euthyphron, Apology--Politeia, Timaeus, Critias--the Laws, Minos, Epinomis -- Criton, Phaedon, Letters), the rest he left unarranged, though on what grounds he was led to do so it is not easy to discover. Thrasylus, in the age of Tiberius, with reference to the above-named division into investigating and instructing dialogues, divided the whole number into tetralogies, probably because Plato had given intimation of his intention to add as a conclusion to the dialogues Theaetetus, Sophistes, and Politicus, one called Philosophus, and to the trilogy of the Politeia, Timaeus, and Critias, the Hermocrates (Plat. Politic.
p. 257a. Critias,
p. 108a. c.).
In place of the unwritten, if intended, Philosophus, Thrasylus adds to the first of the two trilogies, and as the first member of it, the Cratylus; to the second, in place of the Hermocrates, and again as the first member, the Clitophon. (D. L. 3.56
; comp. Albin. Isag,
&c. p. 129). Although this division appears to have been already usual in Varro's time (de Ling. Lat.
6.80, Bip.), and has been adopted in many manuscripts, as well as in the older editions, it is not more satisfactory than the others which have been mentioned, partly because it combines genuine and spurious dialogues, partly because, neglecting internal references, it not unfrequently unites according to merely external considerations. Nor have the more recent attempts of Samuel Petitus (Miscell.
3.2), Sydenham (Synopsis, or General View of the Works of Plato,
p. 9), and Serranus, which connect themselves more or less with those earlier attempts, led to any satisfactory arrangement. Yet at the basis of all these different attempts there lies the correct assumption, that the insight into the purport and construction of the separate Platonic dialogues depends upon our ascertaining the internal references by which they are united with each other. As Schleiermacher, for the purpose of carrying out this supposition, endeavored to point out in Plato himself the leading ideas which lay at the foundation, and by means of them to penetrate to the understanding of each of the dialogues and of its connection with the rest, he has become the originator of a new era in this branch of investigation, and might with good reason be termed by I. Bekker, who has done so much for the critical restoration of the text, Platois restitutor.
Schleiermiacher starts with Plato's declaration of the insufficiency of written communication. If he regarded this as the lifeless image of living colloquy, because, not being able to unfold its meaning, presenting itself to those who do understand as to those who do not, it produces the futile belief of being possessed of knowledge in those who do not know, being only adapted to remind the reader of convictions that have been produced and seized in a lively manner (Plat. Phaedr.
p. 275), and nevertheless spent a considerable part of his long life in the composition of written works, he must doubtless have convinced himself that he was able to meet that deficiency up to a certain point, to communicate to the souls of the readers with science discourses which, being capable of representing their own meaning and of standing in the place of the person who thus implanted them, should show themselves fruitful (ib.
p. 276, &c.; comp. Protag.
p. 329a. 347, c.).
The understanding of many of the dialogues of Plato, however, is rendered difficult by this circumstance, that a single dialogue often contains different investigations, side by side, which appear to be only loosely connected, and are even obscured by one another; and these investigations, moreover, often seem to lead to no conclusion, or even to issue in contradictions. We cannot possibly look upon this peculiarity as destitute of purpose, or the result of want of skill. If, however, it was intended, the only purpose which can have been at the bottom of it must have been to compel the reader, through his spontaneous participation in the investigations proposed, to discover their central point, to supply intermediate members that are wanting, and in that way himself to discover the intended solution of the apparent contradictions. If the reader did not succeed in quite understanding the individual dialogue by itself, it was intended that he should seek the further carrying out of the investigations in other dialogues, and notice how what appeared the end of one is at the same time to be regarded as the beginning and foundation of another. Nevertheless, according to the differences in the investigation and in the susceptibility and maturity for it to be presupposed in the reader, the mode of conducting it and the composition of the dialogue devoted to it would require to be different. Schleierniacher distinguishes three series and classes of dialogues.
In the first he considers that thle germs of dialectic and of the doctrine of ideas begin to unfold themselves in all the freshness of the first youthful inspiration, with the fulness of an imagtinative, dramatically mimetic representation; in the second those germs develop themselves further by means of dialectic investigations respecting the difference between common and philosophical acquaintance with things, respecting notion and knowledge (δόξα
); in the third they receive their completion by means of an objectively scientific working out, with the separation of ethics and physics (Schleiermlacher's Plato,
p. 45, &c.; comp. 2.2, p. 142). To suppose that Plato. when he composed the first of his dialogues, already had clearly before his eyes in distinct outlines the whole series of tihe rest, with all their internal references ;ald connecting links; and farther, that from the beginning to the end he never varied, but needed only to keep on spinning the thread he had once begun, without any where taking it up atlresh,--such a supposition would indeed be preposterous, as Heremann remarks against Schleiernimacher (l.c..
p. 354. 56).
But the assumption above referred to respecting the composition and succession of the dialogues of Plato by no means depends upon any such supposition.
It is enough to believe that tihe fundamental germs of his system early malmde their appearance in the mind of Plato in a definite form, and attained to their development inr a natural mmanuer through the power that resided in them. We need suppose in the case of Plato only what may be demonstrated in the case of other great thinkers of more modern times, as Des Cartes, Spinozn, Fichte, Schelling. Nay, we are not cvel compelled to assume (what indeed is very improbable) that the succession of the dialogues according to their internal references must coincide with the chronological order in which they were composed. Why should not Plato, while he had already commenced works of the third class, have found occasion now and then to return to the completion of the dialogues of the second, or even of the first class ?
As regards, however, the arrangements in detail, we will not celly that Schleiermacher, in the endeavour to assign its place to every dialogue according to the presupposed connection with all the rest running through the series, has now and then suffered himself to be misled by insecure traces, and has been induced partly to regard some leading dialogues from an incorrect or doubtful point of view, partly to supply references by means of artificial combinations. On the other hand, we believe, after a careful examination of the objections against it that have been made good, that we may adopt the principle of the arrangement and the most important points of it.
The first series embraces, according to Schleiermacher, the larger dialogues, Phaedrus, Protagoras, and Parmenides, to which the smaller ones, Lysis, Laches, Charmides, and Euthyphron are to be added as supplements. When others, on the contrary, declare themselves for a much later composition of the Phaedrus, and Hermann in particular (l.c.
pp. 356, 373, &c.) regards it as the entranceprogramnime (p. 544) written by Plato for the opening of his school, we will indeed admit that the account which makes that dialogue Plato's first youthful composition (Diog. 50.3.38; Olympiod. Vita Plat.
p. 78) can pass for nothing more than a conclusion come to by learned philosophers or grammarians (though the judgments of Euphorion, Panaetius, and Dicaearchus brought forward in favour of the opinion deserve regard); but that the compass of knowledge said to be found in the dialogue, and the fulness and maturity of the thoughts, its similarity to the Symposium and Menexenus, the acquaintance with Egyptian mythology and Pythagorean philosophy, bear indubitable testimony to a later composition, we cannot admit; but we must rather appeal to the fact that the youthful Plato, even before he had visited Egypt and Magna Graecia, might easily have acquired such an amount of knowledge in Athens, the centre of all the philosophical life of that age; and further, that what is brougliht forward as evidence of the compass and maturity of the thoughts is rather the youthful, lively expression of the first conception of great ideas (comp. Van Heusde, Initia Doctr. Plut.
i. p. 197).
With the Phaedrus the Lysis stands connected as a dialectic essay upon love.
But as the Phaedrus contains the outlines of the peculiar leading doctrines of Plato partly still as forebodings expressed in a mythical form, so the Protagoras is distinctly to be regarded as the Socratic method in opposition to the sophistic, in discussions wlich we might term the Propylaea of the doctrine of morals.
The early composition of this dialogue is assumed even by the antagonists of Schleiermacher, they only dispute on insufficient grounds either the gelnuimeness of the smaller dialogues Charmides, Laches and Euthyphron (see on this point Hernmann, p. 443, &c.), or their connection with the Protagoras, which manifests itself in this, that the former had demonstrated the insufficiency of the usual moral definitions in reference to the ideas of virtue as connected with temperance (σωφροσύνη
), bravery, and holiness, to which the latter had called attention generally.
The profound dialogue Parmenides, on the other hand, we cannot with Schleiermacher regard either as a mere dialectic exercise, or as one of the earlier works of Plato (comp. Ed. Zeller's Platonische Studien,
p. 184, &c.), but rather see ourselves compelled to assign it a place in the second series of the dialogues of Plato.
The foundation of this series is formed by the dialogues Theaetetus, Sophistes, and Politicus, which have clearly a mutual connection.
Before the Theaetetus Schleiermacher places the Gorgias, and the connection of the two is indubitable, in so far as they both exhibit the constant and essential in opposition to the changeable and contingent, the former in the domain of cognizance, the latter in that of moral action; and as the Theaetetus is to be placed before the Sophistes, Cratylus and other dialogues, so is the Gorgias to be placed at the head of the Politicus, Philebus and the Politeia. Less certain is the position assigned by Schleiermacher to the Menon. Enthydemus and Cratylus, between the Theaetetus and Sophistes. The Menon seems rather expressly designed to form a connecting link between the investigations of the Gorgias and those of the Theaetetus, and on the one hand to bring into view the distinction discussed in the latter between correct notion and true apprehension, in its application to the idea of virtue; on the other hand, by means of this distinction to bring nearer to its final decision the question respecting the essence of the good, as of virtue and the possibility of teaching it.
It might be more difficult to assign to the Euthydemus its definite place. Although with the ridicule of the empty polemical artifices of sophists which is contained in it, there are connected intimations respecting wisdom as the art of those who are in a condition at the same time to produce and to use what they produce, the dialogue nevertheless should probably be regarded as an occasional piece. The Cratylus opposes to the scoffing art of the sophist, dealing in grammatical niceties, the image of dialectic art which recognises and fashions language as a necessary production of the human mind.
It should, however, find its appropriate place not before the Sophistes (where Schleiermacher places it), but after it, as the application of dialectic to language could hardly become a matter of inquiry until the nature of dialectic had been discussed, as is done in the Sophistes. The Eleatic stranger, when questioned by Socrates respecting the nature and difference of the sophist, the statesman and the philosopher (Soph.
p. 217), answers only the first two of these questions, in the dialogues that bear those names, and if Plato had intended a third and similar investigation respecting the nature of the philosopher, he has not undertaken the immediate fulfilment of his design. Schleiermacher therefore assumes that in the Banquet and Phaedon taken together the model of the philosopher is exhibited in the person of Socrates, in the former as he lived, glorified by the panegyric of Alcibiades, and marked by the function, so especially peculiar to him, of love generating in the beautiful (p. 206); in the latter as he appears in death, longing to become pure spirit. (Schleiermacher's Platon,
2.2. p. 358, &c.)
The contents of the two dialogues, however. and their organization as regarded from the point of view of this assumption, is not altogether intelligible. (Comp. Hermann, p. 525. 27.)
But as little should we, with Ed. Zeller (l.c.
p. 194, &c.), look for the missing member of the trilogy, of which we have part in the Sophistes and Politicus, in the exclusively dialectical Parmenides. (Comp. Hermann, p. 671, note 533.) But Plato might the sooner have given up the separate exhibition of the philosopher, partly inasmuch as the description of him is already mixed up with the representation of the sophist and the politician, partly as the picture is rendered complete by means of the Symposium and the Phaedon, as well as by the books on the state. Meantime the place which Schleiermacher assigns to those two dialogues between the Sophistes and Philebus may be regarded as amply justified, as even Hermann admits in opposition to Ast and Socher (pp. 398, 469, 526). Only we must reserve room at this same place for the Parmenides.
In this most difficult of the Platonic dialogues, which has been treated of at length by Ed. Zeller (l.c.
), Stallbaum (Platonis Parmenides, cum IV. libris Prolegomenoram,
Lips. 1839), Brandis (Geschichte der Griech. Röm. Philosophie,
2.1, p. 234, &c., comp. p. 169, note), and others, we find on the one hand the outlines of the doctrine of ideas with the difficulties which oppose themselves to it briefly discussed, on the other hand a considerably more extended attempt made to point out in connection with the conceptions considered in themselves, and in particular with the most universal of them, the One
the contradictions in which the isolated, abstract contemplation of those conceptions involves us; manifestly in order to pave the way for the solution of those difficulties.
In this the Parmenides is closely connected with the Sophistes, and might be placed immediately after the Cratylus, before the Symposium and Phaedon.
But that the Philebus is to be regarded as the immediate transition from the second, dialectical, series of dialogues to the third, Schleiermacher has incontrovertibly shown; and the smaller dialogues, which as regards their contents and form are related to those of the second series, in so far as they are not banished as spurious into the appendix, should be ranked with them as occasional treatises.
In the third series the order for the books on the state (Politeia), the Timaeus and the Critias, has been expressly marked by Plato himself, and with the books on the state those on the laws connect themselves as a supplement.
Ast, though throughout polemically opposed to Schleiermacher, sees himself compelled in the main to recognise the threefold division made by the latter, as he distinguishes Socratic dialogues, in which the poetic and dramatic prevail (Protagoras, Phaedrus, Gorgias and Phaedon), dialectic dialogues (Theaetetus, Sophistes, Politicus and Cratylus), and purely scientific, or Socratico-Platonic dialogues (Philebus, Symposiuln, Politeia, Timaeus and Critias. (Platons Leben und Schriften,
But through this new conception and designation of the first series, and by adding, in the separation of the second and third series, an external ground of division to the internal one, he has been brought to unsteady and arbitrary assumptions which leave out of consideration the internal references. Socher's attempt to establish in place of such arrangements depending upon internal connection a purely chronological arrangement, depending on the time of their composition (Ueber Platons Schriften,
München, 1820), has been followed by no results that can in any degree be depended on, as the date of the composition can be approximately determined by means of the anachronisms (offences against the time in which they are supposed to take place) contained in them in but a few dialogues as compared with the greatly preponderating number of those in which he has assigned it from mere opinion. K. F. Hermann's undertaking, in the absence of definite external statements, to restore a chronological arrangement of the dialogues according to traces and marks founded in facts, with historical circumspection and criticism, and in doing so at the same time to sketch a faithful picture of the progress of the mental life and development of the writer of them, is considerably more worth notice. (Geschichte und System der Platonischen Philosophie.
1ster Theil, Heidelberg, 1839, p. 368, &c.)
In the first period, according to him, Plato's Socrates betrays no other view of life, or scientific conception, than such as we become acquainted with in the historical Socrates out of Xenophon and other unsuspicious witnesses (Hippias, Ion, Alcibiades I., Charmides, Lysis, Laches, Protagoras, and Euthydemus). Then, immediately after the death of Socrates, the Apology, Criton, Gorgias, Euthyphron, Menon, and Hippias Major belong to a transition step.
In the second, or Megaric period of development dialectic makes its appearance as the true technic of philosophy, and the ideas
as its proper objects (Cratylus, Theaetetus, Sophistes, Politicus, Parmenides). Lastly in the third period the system itself is exhibited (Phaedrus, Menexenus, Symposium, Phaedo, Philebus, Politeia, Timaeus, Critias, and the Laws).
But although Hermann has laboured to establish his assumptions with a great expenditure of acuteness and learning, he has not attained to results that can in any degree stand the test of examination. For the assumptions that Plato in the first period confined himself to an analytic treatment of ideas, in a strictly Socratic manner, and did not attain to a scientific independence till he did so through his removal to Megara, nor to an acquaintance with the Pythagorean philosophy, and so to the complete development of his dialectic and doctrine of ideas, till he did so through his travels,--for these assumptions all that can be made out is, that in a number of the dialogues the peculiar features of the Platonic dialectic and doctrine of ideas do not as yet make their appearance in a decided form.
But on the one hand Hermann ranks in that class dialogues such as the Euthydemus, Menon, and Gorgias, in which references to dialectic and the doctrine of ideas can scarcely fail to be recognised ; on the other it is not easy to see why Plato, even after he had laid down in his own mind the outlines of his dialectic and doctrine of ideas, should not now and then, according to the separate reqnirements of the subject in hand, as in the Protagoras and the smaller dialogues which connect themselves with it, have looked away from them, and transported himself back again completely to the Socratic point of view. Then again, in Hermann's mode of treating the subject, dialogues which stand in the closest relation to each other, as the Gorgias and Theaetetus, the Euthydemus and Theaetetus, are severed from each other, and assigned to different periods; while the Phaedon, the Symposium and the Philebus are separated from the Sophistes and Politicus, with which they are much more closely connected than with the delineative works, the Politeia, Timaeus, &c. (Comp. Brandis, Geschichte der Griechisch-Römischen Philosophie,
2.1, p. 164, &c.)
Lastly, as regards the genuineness of the writings of Plato, we cannot, indeed, regard the investigations on the subject as brought to a definitive conclusion, though we may consider ourselves convinced that only a few occasional pieces, or delineations of Socratic conversations, are open to doubts of any importance, not those dialogues which are to be regarded as the larger, essential members of the system. Even if these in part were first published by disciples of Plato, as by Hermodorus (who has been accused of smuggling in spurious works only through a misunderstanding of a passage in Cicero, Cic. Att. 13.21
), and by Philippus the Opuntian ; and though, further, little can be built upon the confirmation afforded by their having been received into the trilogies of the grammarian Aristophanes, the authenticity of the most important of them is demonstrated by the testimonies of Aristotle and some other incontrovertible authorities (the former will be found carefully collected in Zeller's Platonische Studien,
p. 201, &c. Respecting the latter comp. Hermann, l.c.
i. p. 410, &c.). Notwithstanding these testimonies, the Parmenides, Sophistes, and Politicus (by Socher, l.c.
p. 280, &c.; see on the other hand Hermann, l.c.
p. 506, &100.575, note 131), and the Menon (by Ast, p. 398, &c.; see in reply Hermann, p. 482, &c.), have been assailed on exceedingly insufficient grounds; the books on the Laws in a manner much more deserving of attention (especially by Zeller, l.c.
1-115; but comp. Hermann, p. 547); but yet even the latter are with preponderating probability to be regarded as genuine. On the other hand the Epinomis is probably to be assigned to a disciple of Plato (comp. Hermann, p. 410. 22), the Minos and Hipparchus to a Socratic (A. Böckh, in Platonis Minoen qui vulgo fertur,
p. 9, undertakes to make good the claim of Simon to them).
The second Alcibiades was attributed by ancient critics to Xenophon (Athen. 11.506
c.). The Anterastae and Clitophon are probably of much later origin (see Hermann, p. 420, &100.425, &c.). The Platonic letters were composed at different periods; the oldest of them, the seventh and eighth, probably by disciples of Plato (Hermann, p. 420, &c.).
The dialogues Demodocus, Sisyphus, Eryxias, Axiochus, and those on justice and virtue, were with good reason regarded by ancient critics as spurious, and with them may be associated the Hipparchus, Theages, and the Definitions.
The genuineness of the first Alcibiades seems doubtful, though Hermann defends it (p. 439, &c.).
The smaller Hippias, the Ion, and the Menexenus, on the other hand, which are allowed by Aristotle, but assailed by Schleiermacher (1.2, p. 295, 2.3, p. 367, &c.) and Ast (p. 303, &100.448), might very well maintain their ground as occasional compositions of Plato.
As regards the thorough criticism of these dialogues in more recent times, Stallbaum in particular, in the prefaces to his editions, and Hermann (p. 366, &100.400, &c.), have rendered important services.
However groundless may be the Neo-platonic assumption of a secret doctrine, of which not even the passages brought forward out of the insititious Platonic letters (vii. p. 341e. ii. p. 314c.) contain any evidence (comp. Hermann, i. pp. 544, 744, note 755), the verbal lectures of Plato certainly did contain an extension and partial alteration of the doctrines discussed in the dialogues, with an approach to the number-theory of the Pythagoreans ; for to this we should probably refer the "unwritten assumptions" (ἄγραφα δόγματα
), and perhaps also the divisions (διαιρέσεις
), which Aristotle mentions (Phys.
4.2, ib. Simpl. f. 127, de Generat. et Corrupt.
2.3; ib. Joh. Philop. f. 50; D. L. 3.80
). His lectures on the doctrine of the good, Aristotle, Heracleides Ponticus, and Hestiaeus, had noted down, and from the notes of Aristotle some valuable fragments have come down to us (Arist. de Anima,
1.2; ib. Simpl. et Joh. Philop. ; Aristox. Harmonica,
ii. p. 30; comp. Brandis, de Perditis Aristotelis Libris,
p. 3, &c.; and Trendelenburg, Platonis de Ideis et Numeris Doctrina
). The Aristotelic monography on ideas was also at least in part drawn from lectures of Plato, or conversations with him. (Aristot. Met. 1.9
. p. 990b. 11, &c.; ib. Alex. Aphrod. in Schol. in Arist.
p. 564b. 14, &c.; Brandis, l.c.
p. 14, &c.)
III. The Philosphy of Plato.
The attempt to combine poetry and philosophy (the two fundamental tendencies of the Greek mind), gives to the Platonic dialogues a charm, which irresistibly attracts us, though we may have but a deficient comprehension of their subjectmatter. Even the greatest of the Grecian poets are censured by Plato, not without some degree of passion and partiality, for their want of clear ideas, and of true insight (de Rep.
iii. p. 387a., ii. p. 377, x. pp. 597, c., 605, a., 608, a., v. p. 476b., 479, 472, d., vi. p. 507a., de Leg.
iv. p. 719c., Gorg.
p. 501b.). Art is to be regarded as the capacity of creating a whole that is inspired by an invisible order (Phileb.
pp. 64, 67, Phaedr.
p. 264d.); its aim, to guide the human soul (Phaedr.
pp. 261, a. 277, 100.273, a., de Rep.
x. p. 605c.).
The living, unconsciously-creative impulse of the poet, when purified by science, should, on its part, bring this to a full development. Carrying the Socratic dialogue to greater perfection, Plato endeavours to draw his hearers, by means of a dramatic intuition, into the circle of the investigation; to bring them, by the spur of irony, to a consciousness either of knowledge or of ignorance; by means of myths, partly to waken up the spirit of scientific inquiry, partly to express hopes and anticipations which science is not yet able to confirm. (See Alb. Jahn, Disserratio Plttonica quatum de Causa et Natura Mythorum Platonicorum disputatur, tum Mythus de Amoris Ortu Sorte et Indole explicatur.
Plato, like Socrates, was penetrated with the idea that wisdom is the attribute of the Godhead, that philosophy, springing from the impulse to know,
is the necessity of the intellectual man, and the greatest of the goods in which he participates (Phaedr.
p. 278d., Lysis,
p. 218a., Apolog.
p. 23, Theaet.
p. 155d., Sympos.
p. 204a., Tim.
p. 47a.). When once we strive after Wisdom with the intensity of a lover, she becomes the true consecration and purification of the soul (Phaedr.
p. 60e., Symp.
p. 218b.), adapted to lead us from the nightlike to the true day (de Rep.
vii. p.521, d. vi. p. 485b.).
An approach to wisdom, however, presupposes an original communion with Being,
truly so called ; and this communion again presupposes the divine nature or immortality of the soul, and the impulse to become like
This impulse is the love which generates in Truth, and the development of it is termed Dialectics.
The hints respecting the constitution of the soul, as independent of the body; respecting its higher and lower nature ; respecting the mode of apprehension of the former, and its objects, the eternal and the self-existent ; respecting its corporisation, and its longing by purification to raise itself again to its higher existence: these hints, clothed in the form of mythus (Phaedr.
p. 245c.), are followed up in the Phaedrus
by panegyrics on the love of beauty, and discussions on dialectics (pp. 251-255), here understood more immediately as the art of discoursing (pp. 265, d. 266, b. 269, c.). Out of the philosophical impulse which is developed by Dialectics
not only correct knowledge, but also correct action springs forth. Socrates' doctrine respecting the unity of virtue, and that it consists in true, vigorous, ald practical knowledge; that this knowledge, however, lying beyond sensuous perception and experience, is rooted in self-consciousness and has perfect happiness (as the inward harmony of the soul) for its inevitable consequence :--this doctrine is intended to be set forth in a preliminary manner in the Protagoras and the smaller dialogues attached to it. They aredesigned, therefore, to introduce a foundation for ethics, by the refutation of the common views that were entertained of morals and of virtue. For although not even the words ethics and physics occur in Plato (to say nothing of any independent delineation of the one or the other of these sciences), and even dialectics are not treated of as a distinct and separate province, yet he must rightly be regarded as the originator of the threefold division of philosophy (Aristocles, ap. Euseb. Praep. Ev. 11.33
; comp. Aristot. Top. 1.14
, Anal. Post.
1.33), inasmuch as he had before him the decided object to develop the Socratic method into a scientific system of dialectics, that should supply the grounds of our knowledge as well as of our moral action (physics and ethics), and therefore separates the general investigations on knowledge and understanding, at least relatively, from those which refer to physics and ethics. Accordingly, the Theaetetus, Sophistes, Parmenides, and Cratylus, are principally dialectical; the Protagoras, Gorgias, Politicus, Philebus, and the Politics, principally ethical; while the Timaeus is exclusively physical. Plato's dialectics and ethics, however, have been more successful than his physics.
The question, "What is knowledge," had been brought forward more and more definitely, in proportion as the development of philosophy generally advanced. Each of the three main branches of the ancient philosophy, when at their culminating point, had made a trial at the solution of that question, and considered themselves bound to penetrate beneath the phenomenal surface of the affections and perceptions. Heracleitus, for example, in order to gain a sufficient ground for the common
), or, as we should say, for the universally admitted, though in contradiction to his fundamental principle of an eternal generation, postulates a world-consciousness ; Parmenides believed that he had discovered knowledge in the identity of simple, unchangeable Being,
and thought; Philolaus, and with him the flower of the Pythagoreans generally, in the consciousness we have of the unchangeable relations of number and measure. When, however, the conflict of these principles, each of them untenable in its own one-sidedness, had called forth the sophists, and these had either denied knowledge altogether, or resolved it into the mere opinion of momentary affection, Socrates was obliged above all things to show, that there was a knowledge independent of the changes of our sensuous affections, and that this knowledge is actually found in our inalienable consciousness respecting moral requirements, and respecting the divinity, in conscientious self-intellection. To develope this by induction from particular manifestations of the moral and religious sense, and to establish it, by means of definition, in a comprehensible form,--that is, in its generality,--such was the point to which his attention had mainly to be directed. Plato, on the contrary, was constrained to view the question relating to the essence and the material of our knowledge, as well of that which develops itself for its own sake, as of that which breaks out into action,--of the theoretical as well as of the practical, more generally,
and to direct his efforts, therefore, to the investigation of its various forms.
In so doing he became the originator of the science of knowledge,--of dialectics. No one before him had gained an equally clear perception of the subjective and objective elements of our knowledge; no one of the theoretical and the practical side of it; and no one before him had attempted to discover its forms and its laws.
The doctrine of Heracleitus, if we set aside the postulate of a universal world-consciousness, had been weakened down to the idea that knowledge is confined to the consciousness of the momentary affection which proceeds from the meeting of the motion of the subject with that of the object; that each of these affections is equally true, but that each, on account of the incessant change of the motions, must be a different one.
With this idea that of the atomistic theory coincided, inasmuch as it was only by means of arbitrary hypotheses that the latter could get over the consciousness of ever-changing sensuous affections.
In order to refute this idea from its very foundation, once for all, Plato's Theaetetus sets forth with great acuteness the doctrine of eternal generation, and the results which Protagoras had drawn from it (p. 153, &c.); he renounces the apparent, but by no means decisive grounds, which lie against it (p. 157e. &c.); but then demonstrates that Protagoras must regard his own assertion as at once true and false; that he must renounce and give up all determinations respecting futurity, and consequently respecting utility ; that continuity of motion being presuplposed, no perception whatever could be attained; and that the comparison and combination of the emotions or perceptions presupposes a thinking faculty peculiar to the soul (reflection), distinct from mere feeling (pp. 171, &100.179, 182-184).
The man who acknowledges this, if he still will not renounce sensualism, yet will be inclined from his sense-perceptions to deduce recollection; from it, conception ; from conception, when it acquires firmness, knowledge (Phaedo,
p. 96c.); and to designate the latter as correct conception; although he will not be in a condition to render any account of the rise of incorrect conceptions, or of the difference between those and correct ones, unless he presupposes a knowledge that lies, not merely beyond conception generally, but even beyond correct conception, and that carries with it its own evidence (Theaet.
He will also be obliged to give up the assertion, that knowledge consists in right conception, united with discourse or explanation ; for even thus an absolutely certain knowledge will be presupposed as the rule or criterion of the explanation, whatever may he its more accurate definition (p. 200c. &c.). Although, therefore, Plato concludes the dialogue with the declaration that he has not succeeded in bringing the idea of knowledge into perfect clearness (p. 210a.), but that it must be something which excludes all changeableness, something which is its own guarantee, simple, uniform, indivisible (p. 205c., comp. 202, d.), and not to be reached in the science of numbers (p. 195d.): of this the reader, as he spontaneously reproduces the investigation, was intended to convince himself (comp. Charmid.
p. 166, 100.169, c., Sophist.
That knowledge, however, grounded on and sustained by logical inference (αἰτίας λογισμῶ
p. 98a., de Rep.
iv. p. 431c.), should verify itself through the medium of true ideas (Tim.
p. 51c., de Rep.
vi. p. 54d.), can only be considered as the more perfect determination of the conclusion to which he had come in the Theaetetus.
But before Plato could pass on to his investigations respecting the modes of development and the forms
of knowledge, he was obliged to undertake to determine the objects
of knowledge, and to grasp that knowledge in its objective phase. To accomplish this was the purpose of the Sophistes, which immediately attaches itself to the Theaetetus, and obviously presupposes its conclusions.
In the latter dialogue it had already been intimated that knowledge
can only take place in reference to real existence (Theaet.
p. 206e. and 201, a.).
This was also the doctrine of the Eleatics, who nevertheless had deduced the unconditional unity and unchangeableness of the existent, from the inconceivableness of the non-existent. If, however, non-existence is absolutely inconceivable, then also must error, false conception, be so likewise. First of all, therefore, the non-existent was to be discussed, and shown to have, in some sort, an existence, while to this end existence itself had to be defined.
In the primal substance, perpetually undergoing a process of transformation, which was assumed by the Ionian physiologists, the existent, whether understood as duality, trinity, or plurality, cannot find place (p. 242d.); but as little can it (with the Eleatics) be even so much as conceived in thought as something absolutely single and one, without any multiplicity (p. 244b. &c.). Such a thing would rather again coincide with Non-existence. For a multiplicity even in appearance only to be admitted, a multiformity of the existent must be acknowledged (p. 245c. d.). Manifold existence, however, cannot be a bare multiformity of the tangible and corporeal (p. 246a. f.), nor yet a plurality of intelligible incorporeal Essences (Ideas), which have no share either in Action or in Passion, as Euclid and his school probably taught ; since so conceived they would be destitute of anv influence on the world of the changeable, and would indeed themselves entirely elude our cognizance (p. 248a. f.).
But as in the Theaetetus, the inconceivableness of an eternal generation, without anything stable, had been the result arrived at (comp. Sophist.
p. 249b.), so in the Sophistes the opposite idea is disposed of, namely, that the absolutely unchangeable existence alone really is,
and that, all change is mere appearance. Plato was obliged. therefore, to undertake this task,--to find a Being
instead of a Becoming,
and vice versâ, and then to show how the manifold existences stand in relation to each other, and to the changeable, i. e. to phenomena. Existence, Plato concludes. can of itself consist neither in Rest nor in Motion, yet still can share in both, and stand in reciprocal community (p. 250a. &c.).
But certain ideas absolutely exclude one another, as rest, for example, excludes motion, and sameness difference. What ideas, then, are capable of being united with each other, and what are not so, it is the part of science (dialectics
) to decide (p. 252e.).
By the discussion of the relation which the ideas of rest and motion. of sameness and difference, hold to each other, it is explained how motion can be the same, and not the same, how it can be thought of as being and yet not being; consequently, how the non-existent denotes only the variations
of existence, not the bare negation
of it (p. 256d. &c.).
That existence is not at variance with becoming,
and that the latter is not conceivable apart front the former, Plato shows in the case of the two principal parts of speech, and their reciprocal relation (p. 258. c., &100.262). From this it becomes evident in what sense dialectics can be characterised at once as the science of understanding, and as the science of the self-existent, as the science of sciences.
In the Phaedrus (p. 261 ; comp. pp. 266, b. 270, d.) it is presented to us in the first instance as the art of discoursing. and therewith of the true education of the soul and of intellection.
In the Sophistes (p. 261e. &c.) it appears as the science of the true connection of ideas; in the Philebns (p. 16c.) as the highest gift of the gods, as the true Promethean fire; while in the Books on the Republic (vi. p. 511b.) pure ideas, freed from all form and presupposition, are shown to be grasped and developed by it.
In the Theaetetus simple ideas, reached only by the spontaneous activity of thought, had presented themselves as the necessary conditions of knowledge ; in the Sophistes, the objects
of knowledge come before us as a manifold existence, containing in itself the principles of all changes.
The existence of things, cognisable only by means of conception, is their true essence, their idea.
Hence the assertion (Parmen.
p. 135b.) that to deny the reality of ideas is to destroy all scientific research. Plato, it is true, departed from the original meaning of the word idea (namely, that of form or figure) in which it had been employed by Anaxagoras, Diogenes of Apollonia, and probably also by Democritus; inasmuch as he understood by it the unities (ἑνάσες, μονάδες
) which he at the basis of the visible, the changeable, and which can only be reached by pure thinking (εἰλικρινὴς διάνοια
p. 247, de Rep.
ii. p. 380, ix. p. 585b. vi. p. 507b., Phileb.
p. 15, Tim.
p. 51b.); but he retained the characteristic of the intuitive and real, in opposition to the mere abstractness of ideas which belong simply to the thinking which interposes itself.
He included under the expression idea
every thing stable amidst the changes of mere phenomena, all really existing and unchangeable definitudes, by which the changes of things and our knowledge of them are conditioned, such as the ideas of genus and species, the laws and ends of nature, as also the principles of cognition, and of moral action, and the essences of individual, concrete, thinking souls (Phileb.
p. 15a., de Rep.
vii. p. 532a., Tim
p. 51, Phaedo,
p. 100b. p. 102. c. &c). To that only which can be conceived as an entirely formless and undetermined mass, or as a part of a whole, or as an arbitrary relation, do no ideas whatever correspond (Parm.
But how are we to understand the existence of ideas in things? Neither the whole conception, nor merely a part of it, can reside in the things; neither is it enough to understand the ideas to be conceptions, which the soul beholds together with
the things (that is, as we should call them, subjectively valid conceptions or categories), or as bare thoughts without reality. Even when viewed as the archetypes of the changeable, they need some more distinct definition, and some security against obvious objections.
This question and the difficulties which lie against its solution, are developed in the Parmenides, at the beginning of the dialogue, with great acuteness. To introduce the solution to that question, and the refutation of these difficulties, is the evident intention of the succeeding dialectical antinomical 3
discussion of the idea of unity, as a thing being and not being, according as it is viewed in relation to itself and to what is different. How far Plato succeeded in separating ideas from mere abstract conceptions, and making their reality
distinct from the natural causality of motion, we cannot here inquire. Neither can we enter into any discussions respecting the Platonic methods of division, and of the antinomical definitions of ideas, respecting the leading principles of these methods, and his attempt in the Cratylus to represent words
as the immediate copy of ideas, that is, of the essential
in things, by means of the fundamental parts of speech, and to point out the part which dialectics must take in the development of language. While the foundation which Plato lays for the doctrine of ideas or dialectics must be regarded as something finished and complete in itself, yet the mode in which he carries it out is not by any means beyond the reach of objections ; and we can hardly assume that it had attained any remarkably higher development either in the mind of Plato himself, or in his lectures, although he appears to have been continually endeavouring to grasp and to represent the fundamental outlines of his doctrine from different points of view, as is manifest especially from the argumentations which are preserved to us in Aristotle's work on Plato's ideas. (Brandis, de perditis Aristotelis Libris de Ideis et de Bono,
p. 14, &c.; also Handbuch der Geschichte der Griechisch-Römischen Philosophie,
vol. ii. p. 227, &c.)
That Plato, however, while he distinctly separated the region of pure thinking or of ideas from that of sensuous perception and the world of phenomena, did not overlook the necessity of the communion between the intelligible and the sensible world, is abundantly manifest from the gradations which he assumes for the development of our cognition.
In the region of sense--perception, or conception, again, he distinguishes the comprehension of imayes,
and that of objects
), while in the region of thinking he separates the knowledge of those relations which belong indeed to thinking, but which require intuition in the case of sensuous objects, from the immediate grasp by thought of intelligible objects or ideas themselves, that is, of ultimate principles, devoid of all presupposition (διάνοια, νοῦς
). To the first gradation of science, that is, of the higher department of thinking, belong principally, though not exclusively, mathematics; and that Plato regarded them (though he did not fully realise this notion) as a necessary means for elevating experience into scientific knowledge, is evident from hints that occur elsewhere. (Comp. Brandis, Handbuch,
&c. vol. ii. pp. 269, &c.--274, &c.) The fourfold
division which he brings forward, and which is discussed in the De Republica
(vi. p. 509, &c.) he appears to have taken up more definitely in his oral lectures, and in the first department to have distinguished perception from experience (αἴσθησις
), in the second to have distinguished mediate knowledge from the immediate thinking consciousness of first principles (ἐπιστήμη
from νοῦς ;
see Arist. De Anima,
1.2, with the note of Trendelenburg).
Although, therefore, the carrying out of Plato's dialectics may be imperfect, and by no means proportional to this excellent foundation, yet he had certainly taken a steady view of their end, namely, to lay hold of ideas more and more distinctly in their organic connection at once with one another and with the phenomenal world, by the discovery of their inward relations; and then having done this, to refer them to their ultimate basis.
This ought at the same time to verify itself as the unconditional ground of the reality of objects and of the power we have to take cognisance of them, of Being and of Thought ; being comparable to the intellectual sun. Now this absolutely unconditional ground Plato describes as the idea of the good (De Rep).
vi. p. 505, &c.), convinced that we cannot imagine any higher definitude than the good ;
but that we must, on the contrary, measure all other definitudes by it, and regard it as the aim and purpose of all our endeavours, nay of all developments. Not being in a condition to grasp the idea of the good with fill distinctness, we are able to approximate to it only so far as we elevate the power of thinking to its original purity (Brands. ibid.
pp . 281, &100.324, &c.). Although the idea of the good, as the ultimate basis both of the mind and of the realities laid hold of by it, of thought and of existence, is, according to him, more elevated than that of spirit or actual existence itself, yet we can only imagine its activity as the activity of the mind. Through its activity the determinate natures of the ideas, which in themselves only exist, acquire their power of causation, a power which must be set down as spiritual, that is, free. Plato, therefore, describes the idea of the good, or the Godhead, sometimes teleologically, as the ultimate purpose of all conditioned existence ; sometimes cosmologically, as the ultimate operative cause; and has begun to develope the cosmological, as also the physico-theological proof for the being of God; but has referred both back to the idea of the Good,
as the necessary presupposition to all other ideas, and our cognition of them. Moreover, we find him earnestly endeavouring to purify and free from its restrictions the idea of the Godhead, to establish and defend the belief in a wise and divine government of the world; as also to set aside the doubt that arises from the existence of evil and suffering in the world. (Brandis, Ibid.
p. 331, &c.)
But then, how does the sensuous world, the world of phenomena, come into existence? To suppose that in his view it was nothing else than the mere subjective appearance which springs from the commingling of the ideas, or the confused conception of the ideas (Ritter, Geschichte der Philosophie,
vol. ii. pp. 295, &100.339, &c.), not only contradicts the declarations of Plato in the Philebus
(p. 23b. 54, a.), Timaeus
(pp. 27, e. 48, e. 51), &c., but contradicts also the dualistic tendency of the whole of the ancient philosophy.
He designates as the, we may perhaps say, material ground of the phenomenal world, that which is in itself unlimited, ever in a process of becoming,
never really caisting,
the mass out of which every thing is formed, and connects with it the idea of extension, as also of unregulated motion; attributes to it only the joint causality of necessity, in opposition to the free causality of ideas, which works towards ends, and, by means of his mythical conception of the soul of the universe, seeks to fill up the chasm between these opposed primary essences.
This, standing midway between the intelligible (that to which the attribute of sameness belongs) and the sensible (the diverse), as the principle of order and motion in the world, according to him, comprehends in itself all the relations of number and measure. Plato had made another attempt to fill up the gap in the development of ideas by a symbolical representation, in the lectures he delivered upon the Good,
mentioned by Aristotle and others.
In these he partly referred ideas to intelligible numbers, in order, probably, that he might be able to denote more definitely their relation of dependence on the Godhead, as the absolute one, as also the relation of their succession and mutual connection; and partly described the Godhead as the ultimate ground both of ideas and also of the material of phenomena, inasmuch as he referred them both to the divine causality-the former immediately as original numbers, the latter through the medium of the activity of the ideas.
But on this Pythagorean mode of exhibiting the highest principles of Plato's doctrine we have but very imperfect information. (Brandis, Ibid.
vol.ii. ], p. 336, &c.)
Both these departments which form the connecting link between Dialectics and Physics, and the principles of Physics themselves, contain only preliminary assumptions and hypothetical declarations, which Plato describes as a kind of recreation from more earnest search after the really existent, as an innocent enjoyment, a rational sport (Tim.
pp. 27, e. 29, b. 59, c.). Inasmuch as physics treat only of the changeable and imitative, they must be contented with attaining probability but they should aim, especially, at investigating teleologically end-causes, that is, free causality, and showing how they converge in the realisation of the idea of the good. All the determinations of the original undetermined matter are realised by corporeal forms;
in these forms Plato attempts to find the natural or necessary basis of the different kinds of feeling and of sensuous perception. Throughout the whole development, however, of his Physiology, as also in the outlines of his doctrine on Health and Sickness, pregnant ideas and clear views are to be met with. (See especially Th. H. Martin, Etudes sur le Timée de Platon,
With the physiology of Plato his doctrine of the Soul is closely connected. Endowed with the same nature as the soul of the world, the human soul is that which is spontaneously active and unapproachable by death, although in its coneetion with the body bound up with the appetitive, the sensuous; and the θυμό
, that which is of the nature of affection or eager impulse, the ground of courage and fear, love and hope, designeod, while subordinating itself to the reason, to restrain sensuality, must be regarded as the link between the rational and the sensuous. (Tim.
p. 69d. 71, b., de Rep.
iv. p. 435, &c. ix. p. 571.) Another link of connection between the intellectual and sensuous nature of the soul is referred to Lore,
which, separated from concupiscent desire, is conceived of as an inspiration that transcends mere mediate intellection, whose purpose is to realise a perpetual striving after the immortal, the eternal ;--to realise, in a word, by a close connection with others, the Good in the form of the Beautifill.
In the Phaedrus Plato speaks of love under the veil of a myth; in the Lysis he commences the logical definition of it ; and in the Symposium, one of the most artistic and attractive of his dialogues, he analyses the different momeneta which are necessary to the complete determination of the idea.
In these and some of the other dialogues, however, beauty is described as the image of the ideas, penetrating the veil of pheomena and apprehended by the purest and brightest exercise of sense, in relation to colours, forms, actions, and morals, as also with relation to the harmonious combination of the Manifold into perfect Unity, and distinctly separated from the Agreeable and the Useful. Art is celebrated as the power of producing a whole, inspired by an invisible arrangement; of grouping together into one form the images of the ideas, which are everywhere scattered around.
That the soul, when separated from the body, -- or the pure spirit, -- is immortal, and that a continuance, in which power and consciousness or insight are preserved, is secured to it, Socrates, in the Phaedo of Plato, when approaching death, endeavours to convince his friends, partly by means of analogies drawn from the nature of things, partly by the refutation of the opposed hypothesis, that the soul is an harmonious union and tuning of the constituents of the body, partly by the attempt to prove the simplicity of the essential nature of the soul, its consequent indestructibility, and its relation to the Eternal, or its pre-existence; partly by the argumentation that the idea of the soul is inseparable from that of life, and that it can never be destroyed by moral evil, -- the only evil to which, properly speaking, it is subjected (comp. de Rep.
x. p. 609b. &c., Phaedr.
p. 245c.). Respecting the condition of the soul after death Plato expresses himself only in myths, and his utterances respecting the Transmigration of Souls also are expressed in a mythical form.
As a true disciple of Socrates, Plato devoted all the energy of his soul to ethics, which again are closely connected with politics.
He paves the way for a scientific treatment of ethics by the refutation of the sophistical sensualistic and hedonistic (selfish) theories, first of all in the Protagoras and the three smaller dialogues attached to it (see above), then in the Gorgias, by pointing ont the contradictions in which the assertions, on the one hand that wrong actions are uglier than right ones but more useful, on the other that the only right recognised by nature is that of the stronger, are involved.
In this discussion the result is deduced, that neither happiness nor virtue can consist in the attempt to satisfy our unbridled and ever-increasing desires (de Rep.
In the Menon the Good is defined as that kind of utility which can never become injurious, and whose realisation is referred to a knowledge which is absolutely fixed and certain,--a knowledge, however, which must be viewed as something not externally communicable, but only to be developed from the spontaneous activity of the soul. Lastly, in the Philebus, the investigation respecting pleasure and pain, which was commenced in the Gorgias, as also that on the idea of the Good, is completed; and this twofold investigation grounded upon the principles of dialectics, and brought into relation with phys cs. Pain is referred to the disturbance of the inward harmony, pleasure to the maintenance, or restoration of it; and it is shown how, on the one hand, true and false, on the other, pure and mixed pleasure, are to be distinguished, while, inasmuch as it (pleasure) is always dependent on the activity out of which it springs, it becomes so much the truer and purer in proportion as the activity itself becomes more elevated.
In this way the first sketch of a table of Goods
is attained, in which the eternal nature of Measure,
that is, the sum and substance of the ideas, as the highest canon, and then the different steps of the actual realisation of them in life, in a regular descending scale, are given, while it is acknowledged that the accompaying pure (unsensuous) pleasure is also to be regarded as a good, but inferior to that on which it depends, the reason and the understanding, science and art. Now, if we consider that, ac cording to Plato, all morality must be directed to the realisation of the ideas in the phenomenal world; and, moreover, that these ideas in their reality and their activity, as also the knowledge respecting them, is to be referred to the Godhead, we can understand how he could designate the highest good as being an assimilation to God. (Theaet.
p. 176a, de Rep.
10.613; comp, Wyttenbach, ad Plut. de Ser. Num. Vind.
In the Ethics of Plato the doctrine respecting virtue is attached to that of the highest good, and its development.
That virtue is essentially one, and the science of the good, had been already deduced in the critical and dialectical introductory dialogues; but it had been also presupposed and even hinted that, without detriment to its unity, different phases of it could be distinguished, and that to knowledge there must be added practice, and an earnest combating of the sensuous functions.
In order to discover these different phases, Plato goes back upon his triple division of the faculties of the soul. Virtue, in other words, is fitness of the soul for the operations that are peculiar to it (de Rep.
i. p. 353d. x. p. 601d.), and it manifests itself by means of its (the soul's) inward harmony, beauty, and health (Gorg.
pp. 504, b. 506, b., Phaedo,
p. 93e., de Rep.
iv. pp. 444, d. 8.554, e.). Different phases of virtue are distinguishable so far as the soul is not pure spirit; but just as the spirit should rule both the other elements of the soul, so also should wisdom, as the inn development of the spirit, rule the other virtues. Ability of the emotive element (θυμοειδές
), when penetrated with wisdom to govern the whole sensuous nature, is Courage.
If the sensuous or appetitive (ἐπιθυμητικόν
) element is brought into unity with the ends of wisdom, moderation or prudence (σωφροσύνη
), as an inward harmony, is the result. If the inward harmony of the activities shows itself active in giving an harmonious form to our outward relations in the world, Virtue exerts itself in the form of Justice (de Rep.
iv. p. 428b. &c.).
That happiness coincides with the inward harmony of virtue, is inferred from this deduction of the virtues, as also from the discussions respecting pleasure (de Rep.
viii. p. 547, &c. ix. p. 580, &c.).
If it be true that the ethico-rational nature of the individual can only develope itself completely in a well-ordered state (de Rep.
6.496, b.), then the object and constitution of the state must perfectly answer to the moral nature of the individual, and politics must be an essential, inseparable part of ethics. While, therefore, Plato considers the state as the copy of a well-regulated individual life (de Rep.
ii. p. 368e. viii. p. 544e. &c.), he demands of it that it should exhibit a perfect harmony, in which everything is common to all, and the individual in all his relations only an organ of the state.
The entire merging of the individual life in the life of the state might have appeared to him as the only effectual means of stemming that selfishness and licence of the citizens, which in his time was becoming more and more predominant. Plato deduces the three main elements of the state from the three different activities of the soul; and just as the appetitive element should be absolutely under control, so also the working class, which answers to it; and the military order, which answers to the emotive element, should develope itself in thorough dependence upon the reason, by means of gymnastics and music; and from that the governing order, answering to the rational faculty, must proceed.
The right of passing from the rank of a guard (δύλακες, τὸ ἐπικουρικὸν
) to that of a ruler, must be established by the capacity for raising oneself from becoming
to knowledge ;
for the ruler ought to be in a condition to extend and confirm the government of the reason in the state more and more, and especially to direct and watch over training and education. Without admitting altogether the impracticability of his state, yet Plato confesses that no realisation of it in the phenomenal world can fully express his idea, but that an approximation to it must be aimed at by a limitation of unconditional unity and community, adapted to circumstances. On this account, with the view of approximating to the given circumstances, he renounces, in his book on the Laws, that absolute separation of ranks; limits the power of the governors, attempts to reconcile freedom with reason and unity, to mingle monarchy with democracy ; distinguishes several classes of rulers, and will only commit to their organically constructed body the highest power under the guarantee of the laws.
[Ch. A. B.
There are numerous editions both of the entire text of Plato, and of separate dialogues. The first was that published by Aldus at Venice, in A. D. 1513.
In this edition the dialogues are arranged in nine tetralogies, according to the division of Thrasyllus (see above).
The next edition was that published at Basle, in 1534.
It was edited chiefly by Johannes Oporinus, who was afterwards professor of Greek in that university.
It does not appear that he made use of any manuscripts, but he succeeded in correcting many of the mistakes to be found in the edition of Aldus, though some of his alterations were corruptions of sound passages.
The edition was, however, enriched by having incorporated with it the commentaries of Proclus on the Timaeus and the State, which had shortly before been discovered by Simon Grynaeus in the library of the university at Oxford, and a triple Greek index,--one of words and phrases, another of proper names, and a third of proverbs to be found in Plato.
The next edition, published at Basle in 1556, was superintended by Marcus Hopperus
, who availed himself of a collation of some manuscripts of Plato made in Italy by Arnoldus Arlenius, and so corrected several of the errors of the previous Basle edition, and gave a large number of various readings.
the edition of H. Stephanus (1578, in three volumes)
is equally remarkable for the careful preparation of the text, by correcting the mistakes of copyists and typographers, and introducing in several instances very felicitous improvements, and for the dishonesty with which the editor appropriated to himself the labours of others without any acknowledgment, and with various tricks strove to conceal the source from which they were derived. His various readings are taken chiefly, if not entirely, from the second Basle edition, from the Latin version of Ficinus, and from the notes of Cornarius.
It is questionble whether he himself collated a single manuscript. The Latin version of Serranus, which is printed in this edition, is very bad.
The occasional translations of Stephanus himself are far better.
The Bipont edition (11 vols. 8vo. A. D. 1781-1786）
contains a reprint of the text of that of Stephanus, with the Latin version of Marsilius Ficinus. Some fresh various readings, collected by Mitscherlich, are added.
It was, however, by Immanuel Bekker that the text of Plato was first brought into a satisfactory condition in his edition, published in 1816-18
, accompanied by the Latin version of Ficinus (here restored, generally speaking, to its original form, the reprints of it in other previous editions of Plato containing numerous alterations and corruptions), a critical commentary, an extensive comparison of various readings, and the Greek scholia, previously edited by Ruhnken, with some additions, together with copious indexes.
The dialogues are arranged according to the scheme of Schleiermacher. The Latin version in this edition has sometimes been erroneously described as that of Wolf.
A joint edition by Bekker and Wolf was projected and commenced, but not completed. The reprint of Bekker's edition, accompanied by the notes of Stephanus, Heindorf, Wyttenbach, &c., published by Priestley (Lond. 1826)
, is a useful edition. Ast's edition (Lips. 1819-1827, 9 vols. 8vo.
, to which two volumes of notes on the four dialogues, Protagoras, Phaedrus, Georgias, and Phaedo, have since been added) contains many ingenious and excellent emendations of the text, which the editor's profound acquaintance with the phraseology of Plato enabled him to effect. G. Stallbaum, who edited a critical edition of the text of Plato (Lips. 1821-1825, 8 vols. 8vo. 4
, and 1826, 8 vols. 12mo.), commenced in 1827 an elaborate edition of Plato, which is not yet quite completed.
This is perhaps the best and most useful edition which has appeared. The edition of J.G. Baiter, J. C. Orelli, and A. G. Winckelmann (one vol. 4to. Zürich, 1839) deserves especial mention for the accuracy of the text and the beauty of the typography.
Editions of one or more dialogues
Of separate dialogues, or collections of dialogues, the editions are almost endless. Those of the Cratylus and Theaetetus, of the Euthyphro, Apologia, Crito, and Phaedo, of the Sophista, Politicus and Parmenides, and of the Philebus and Symposium by Fischer
; of the Lysis, Charmides, Hippias Major, and Phaedrus, of the Gorgias and Theaetetus, of the Cratylus, Euthydemus and Parmenides, of the Phaedo, and of the Protagoras and Sophistes by Heindorf
(whose notes exhibit both acuteness and sound judgment); of the Phaedo by Wyttenbach
; of the Philebus, and of the Parmenides by Stallbaum
(in the edition of the latter of which the commentary of Proclus is incorporated), are most worthy of note.
Of the translations of Plato the most celebrated is the Latin version of Marsilius Ficinus (Flor. 1483-1484, and frequently reprinted).
It was in this version, which was made from manuscripts, that the writings of Plato first appeared in a printed form.
The translation is so extremely close that it has almost the authority of a Greek manuscript, and is of great service in ascertaining varieties of reading.
This remark, however, does not apply to the later, altered editions of it, which were published subsequently to the appearance of the Greek text of Plato.
There is no good English translation of the whole of Plato, that by Taylor being by no means accurate
. The efforts of Floyer Sydenham were much more successful, but he translated only a few of the pieces.
There is a French translation by V. Cousin.
Schleiermacher's German translation is incomparably the best, but is unfortunately incomplete.
There is an Italian translation by Dardi Bembo.
The versions of separate dialogues in different languages are too numerous to be noticed.
We have space to notice only the following out of the very numerous works written in illustration of Plato: -- Platonis Dialogorum Argumenta Exposita et Illustrata,
by Tiedemann (Bip. 1786); System der Platonischen Philosophie,
by Tennemann (4 vols. 8vo. Leipz. 1792-5); Initia Philosophiae Platonicae,
by P. G. Van Heusde (ed. ii. Lugd. Bat. 1842); Platons Leben und Schriften,
by G. A. F. Ast (Leipz. 1816); Geschichte und System der Platonischen Philosophic,
by C. F. Hermann (Heidelb. 1838); Platonis de Ideis et Numeris Doctrina ea Aristotele illustrata,
by F. A. Trendelenburg (Lips. 1826); Platonische Studien,
by E. Zeller (Tübing. 1839).
There are also numerous smaller treatises by Böckh, C. F. Hermann, Stallbaum, &c., which may be consulted with profit. Schleiermacher's introductions to some of the dialogues have been translated and published in a separate form in English.