Numenius accepted both Pythagoras and Plato as the two authorities one should follow in philosophy, but he regarded Plato's authority as subordinate to that of Pythagoras, whom he considered to be the source of all true philosophy—including Plato's own. For Numenius it is just that Plato wrote so many philosophical works, whereas Pythagoras' views were originally passed on only orally.
The 1578 edition of Plato's complete works published by Henricus Stephanus (Henri Estienne) in Geneva also included parallel Latin translation and running commentary by Joannes Serranus (Jean de Serres). It was this edition which established standard Stephanus pagination, still in use today.
The oldest surviving complete manuscript for many of the dialogues is the Clarke Plato (Codex Oxoniensis Clarkianus 39, or Codex Boleianus MS E.D. Clarke 39), which was written in Constantinople in 895 and acquired by Oxford University in 1809. The Clarke is given the siglum B in modern editions. B contains the first six tetralogies and is described internally as being written by "John the Calligrapher" on behalf of Arethas of Caesarea. It appears to have undergone corrections by Arethas himself. For the last two tetralogies and the apocrypha, the oldest surviving complete manuscript is Codex Parisinus graecus 1807, designated A, which was written nearly contemporaneously to B, circa 900 AD. A must be a copy of the edition edited by the patriarch, Photios, Teacher of Arethas.A probably had an initial volume containing the first 7 tetralogies which is now lost, but of which a copy was made, Codex Venetus append. class. 4, 1, which has the siglum T. The oldest manuscript for the seventh tetralogy is Codex Vindobonensis 54. suppl. phil. Gr. 7, with siglum W, with a supposed date in the twelfth century. In total there are fifty-one such Byzantine manuscripts known, while others may yet be found.
Many recent Philosophers have diverged from what some would describe as the ontological Models and moral ideals characteristic of traditional Platonism. A number of these postmodern Philosophers have thus appeared to disparage Platonism from more or less informed perspectives. Friedrich Nietzsche notoriously attacked Plato's "idea of the good itself" along with many fundamentals of Christian morality, which he interpreted as "Platonism for the masses" in one of his most important works, Beyond Good and Evil (1886). Martin Heidegger argued against Plato's alleged obfuscation of Being in his incomplete tome, Being and Time (1927), and the Philosopher of science Karl Popper argued in The Open Society and Its Enemies (1945) that Plato's alleged proposal for a utopian political regime in the Republic was prototypically totalitarian. The political Philosopher and professor Leo Strauss is considered by some as the prime thinker involved in the recovery of Platonic thought in its more political, and less metaphysical, form. Strauss' political approach was in part inspired by the appropriation of Plato and Aristotle by medieval Jewish and Islamic political Philosophers, especially Maimonides and Al-Farabi, as opposed to the Christian metaphysical tradition that developed from Neoplatonism. Deeply influenced by Nietzsche and Heidegger, Strauss nonetheless rejects their condemnation of Plato and looks to the dialogues for a solution to what all three latter day thinkers acknowledge as 'the crisis of the West.'
The Oxford Classical Texts offers the current standard complete Greek text of Plato's complete works. In five volumes edited by John Burnet, its first edition was published 1900-1907, and it is still available from the publisher, having last been printed in 1993. The second edition is still in progress with only the first volume, printed in 1995, and the Republic, printed in 2003, available. The Cambridge Greek and Latin Texts and Cambridge Classical Texts and Commentaries series includes Greek editions of the Protagoras, Symposium, Phaedrus, Alcibiades, and Clitophon, with English philological, literary, and, to an extent, philosophical commentary. One distinguished edition of the Greek text is E. R. Dodds' of the Gorgias, which includes extensive English commentary.
The most important aspect of this interpretation of Plato's metaphysics is the continuity between his teaching and the neoplatonic interpretation of Plotinus or Ficino which has been considered erroneous by many but may in fact have been directly influenced by oral transmission of Plato's doctrine. A modern scholar who recognized the importance of the unwritten doctrine of Plato was Heinrich Gomperz who described it in his speech during the 7th International Congress of Philosophy in 1930. All the sources related to the ἄγραφα δόγματα have been collected by Konrad Gaiser and published as Testimonia Platonica. These sources have subsequently been interpreted by scholars from the German Tübingen School of interpretation such as Hans Joachim Krämer or Thomas A. Szlezák.
Plato may have traveled in Italy, Sicily, Egypt and Cyrene. Said to have returned to Athens at the age of forty, Plato founded one of the earliest known organized schools in Western Civilization on a plot of land in the Grove of Hecademus or Academus. The Academy was a large enclosure of ground about six stadia outside of Athens proper. One story is that the name of the Academy comes from the ancient hero, Academus; still another story is that the name came from a supposed former owner of the plot of land, an Athenian citizen whose name was (also) Academus; while yet another account is that it was named after a member of the army of Castor and Pollux, an Arcadian named Echedemus. The Academy operated until it was destroyed by Lucius Cornelius Sulla in 84 BC. Neoplatonists revived the Academy in the early 5th century but there was no institutional continuity with Plato's school, and it operated until 529 AD, when it was closed by Justinian I of Byzantium. Many intellectuals were schooled in the Academy, the most prominent one being Aristotle.
Some 250 known manuscripts of Plato survive. The texts of Plato as received today apparently represent the complete written philosophical work of Plato and are generally good by the standards of textual criticism. No modern edition of Plato in the original Greek represents a single source, but rather it is reconstructed from multiple sources which are compared with each other. These sources are medieval manuscripts written on vellum (mainly from 9th to 13th century AD Byzantium), papyri (mainly from late antiquity in Egypt), and from the independent testimonia of other authors who quote various segments of the works (which come from a variety of sources). The text as presented is usually not much different from what appears in the Byzantine manuscripts, and papyri and testimonia just confirm the manuscript tradition. In some editions however the readings in the papyri or testimonia are favoured in some places by the editing critic of the text. Reviewing editions of papyri for the Republic in 1987, Slings suggests that the use of papyri is hampered due to some poor editing practices.
The modern standard complete English edition is the 1997 Hackett Plato, Complete Works, edited by John M. Cooper. For many of these translations Hackett offers separate volumes which include more by way of commentary, notes, and introductory material. There is also the Clarendon Plato Series by Oxford University Press which offers English translations and thorough philosophical commentary by leading scholars on a few of Plato's works, including John McDowell's version of the Theaetetus. Cornell University Press has also begun the Agora series of English translations of classical and medieval philosophical texts, including a few of Plato's.
To help establish the text, the older evidence of papyri and the independent evidence of the testimony of commentators and other authors (i.e., those who quote and refer to an old text of Plato which is no longer extant) are also used. Many papyri which contain fragments of Plato's texts are among the Oxyrhynchus Papyri. The 2003 Oxford Classical Texts edition by Slings even cites the Coptic translation of a fragment of the Republic in the Nag Hammadi library as evidence. Important authors for testimony include Olympiodorus the Younger, Plutarch, Proclus, Iamblichus, Eusebius, and Stobaeus.
If Plato's important dialogues do not refer to Socrates' execution explicitly, they allude to it, or use characters or themes that play a part in it. Five dialogues foreshadow the trial: In the Theaetetus (210d) and the Euthyphro (2a–b) Socrates tells people that he is about to face corruption charges. In the Meno (94e–95a), one of the men who brings legal charges against Socrates, Anytus, warns him about the trouble he may get into if he does not stop criticizing important people. In the Gorgias, Socrates says that his trial will be like a Doctor prosecuted by a cook who asks a jury of children to choose between the doctor's bitter Medicine and the cook's tasty treats (521e–522a). In the Republic (7.517e), Socrates explains why an enlightened man (presumably himself) will stumble in a courtroom situation. The Apology is Socrates' defense speech, and the Crito and Phaedo take place in prison after the conviction. In the Protagoras, Socrates is a guest at the home of Callias, son of Hipponicus, a man whom Socrates disparages in the Apology as having wasted a great amount of money on sophists' fees.
Their account is in full agreement with Aristotle's description of Plato's metaphysical doctrine. In Metaphysics he writes: "Now since the Forms are the causes of everything else, he [i.e. Plato] supposed that their elements are the elements of all things. Accordingly the material principle is the Great and Small [i.e. the Dyad], and the essence is the One (τὸ ἕν), since the numbers are derived from the Great and Small by participation in the One" (987 b). "From this account it is clear that he only employed two causes: that of the essence, and the material cause; for the Forms are the cause of the essence in everything else, and the One is the cause of it in the Forms. He also tells us what the material substrate is of which the Forms are predicated in the case of sensible things, and the One in that of the Forms—that it is this the duality (the Dyad, ἡ δυάς), the Great and Small (τὸ μέγα καὶ τὸ μικρόν). Further, he assigned to these two elements respectively the causation of good and of evil" (988 a).
The usual system for making unique references to sections of the text by Plato derives from a 16th-century edition of Plato's works by Henricus Stephanus. An overview of Plato's writings according to this system can be found in the Stephanus pagination article.
By the 19th century, Plato's reputation was restored, and at least on par with Aristotle's. Notable Western Philosophers have continued to draw upon Plato's work since that time. Plato's influence has been especially strong in mathematics and the sciences. He helped to distinguish between pure and applied mathematics by widening the gap between "arithmetic", now called number theory and "logistic", now called arithmetic. He regarded "logistic" as appropriate for Business men and men of war who "must learn the art of numbers or he will not know how to array his troops," while "arithmetic" was appropriate for Philosophers "because he has to arise out of the sea of change and lay hold of true being." Plato's resurgence further inspired some of the greatest advances in logic since Aristotle, primarily through Gottlob Frege and his followers Kurt Gödel, Alonzo Church, and Alfred Tarski. Albert Einstein suggested that the scientist who takes philosophy seriously would have to avoid systematization and take on many different roles, and possibly appear as a Platonist or Pythagorean, in that such a one would have "the viewpoint of logical simplicity as an indispensable and effective tool of his research."