Radical thinking about conventions and the relationships among language, reality, perception, belief, and convention were associated by Thucydides with the mistakes of the Athenian citizenry in the Peloponnesian Wars and by later thinkers of the fourth century with the similarly great mistakes of the two oligarchic revolutions of 411 and 404-403. After the first restoration of the democracy in 411, Antiphon of Rhamnous was put on trial as a traitor and executed. After the second restoration in 403, a general amnesty prevented similar treatment of the surviving oligarchs, but the trial and execution of Sokrates in 399 on charges of impiety and corruption of the youth were surely motivated by popular anger at the intellectual presumptions of Sokrates, and especially of his associates Kritias of the Thirty Tyrants and Alkibiades, the wily and treacherous Athenian aristocrat (Xenophon Memorabilia book 1). Unlike Antiphon or any other figure in the intellectual enlightenment of the late fifth century, however, Sokrates had inspired a wide array of disciples to rise to his defense against the Athenians for their unfair treatment and to continue his intellectual goal of provoking individuals to think for themselves and to understand the bases of their own moral character (Vander Waerdt 1994; Kahn 1996). This goal was continuous with, and probably shared by, the sophistic culture and its response to the moral crises of the late Peloponnesian War (Raaflaub 1989), but, in its pursuit of true knowledge, fundamentally opposed to the stereotypes of‘‘sophistry.’’
Sokrates wrote nothing himself. He practiced the activity Plato would dub ‘‘philosophy’’ without any institutional basis, but by wandering the streets of Athens and engaging the people he met in conversation. In several passages of the Platonic corpus he even claims that his wisdom consists in not believing that he knows what he does not know (Apology 21D); his purpose is above all negative, to test the professed ideas of others to see whether they are real ideas ( Theaetetus 150B-D). At the same time, the dialogues imply consistently that there does exist a truth to be discovered by those who are able (Vlastos 1991; 1994). The historical Sokrates thus remains no less a conundrum than any other of the pre-Socratic or Sophistic thinkers, and it appears from anecdotes (e. g., Diogenes Laertios 3.35) that the very definition of Socratic philosophy was disputed among his followers after his death. The views and writings of the many Socratic disciples survived into Hellenistic times to become perceived as the heritage of all philosophy in its many varieties, including the hedonism of the Epikureans, supposed to derive from Sokrates through Aristippos; the anti-hedonist moralism of the Cynics and Stoics, supposed to derive from Sokrates through Anti-sthenes; and the skepticism of the Academics, probably first attributed to Sokrates in Arkesilaos’ reading (mid-third century) of certain passages in Plato (Long 1988). But Plato had emerged by the 380s as the dominant spokesman.
Like Sokrates, Plato aimed primarily to convert others to the pursuit of truth for its own sake and for the sake of a just moral and political order: like the conversations of the Sokrates he portrays, his literary dialogues, especially the early ones, were meant not primarily to lay out dogma but to inspire readers to undertake their own reasoned inquiry into the truths of ethics, politics, epistemology, ontology, the soul, and the kosmos. In many ways, however, Plato was far more dogmatic and formal than Sokrates. Certainly by the time he wrote his most lengthy, so-called ‘‘middle’’ dialogues (classified as such primarily on the basis of style), Plato was teaching in the formal setting of the Academy, the educational institution he founded in the 380s, possibly in rivalry with Isokrates, one of many known fourth-century disciples of Gorgias, who remained skeptical about human access to ultimate truth and continued a more sophistic education in argument and rhetoric in a large institution of his own (Eucken 1983). In the Academy, if not in his ‘‘exoteric’’ dialogues intended for publication, Plato seems to have taught substantial doctrine: Aristotle of Stagira, a member of the Academy from his arrival in Athens in about 367 at the age of 17 to Plato’s death in 348/7, reports many doctrines of his master with which he variously agrees or takes issue. The major modern debate about Plato concerns the degree to which his surviving dialogues communicate positive doctrine or recommended courses of argument, at one extreme, or remain largely aporetic or even arbitrary stimuli to the reader’s personal engagement in philosophy, at the other.
In the early, Socratic dialogues, where he may have been still trying to establish his voice as a Socratic authority, Plato presents Sokrates in conversation with self-proclaimed experts about the meaning of moral concepts such as courage, piety, friendship, or justice. Sokrates offers no positive views of his own, but uses the so-called ‘‘elenctic’’ method - the reduction of any view articulated to a logical contradiction or other absurdity, compared by Aristotle to the tactics of Zenon and the Eleatics - to demonstrate to others the incoherence of their views. In the middle dialogues, Plato attributes to Sokrates not only interrogating dialogue, but also longer expositions of positive doctrine regarding the range of topics that interest him, and especially the ontological theory of forms and a theory of the soul which explains how the forms can be known. In Phaedo and Republic, especially, Plato has Sokrates lay out the view that the fundamental reality which underlies the changeable, conflicting appearances of the world apparent to our senses is constituted by a set of so-called ‘‘forms,’’ or objective entities corresponding to concepts such as beauty, courage, and, ultimately, the good, which are eternal, unchanging, and causative of the various instances of goodness etc. in the physical world. In Meno and Phaedrus, Plato has Sokrates outline a theory of recollection, whereby a soul can know the forms, which are not accessible through ordinary empirical means, through recollection of an acquaintance with the forms that it enjoyed before it was joined with the body in its present incarnation. The doctrine of recollection has a clear Pythagorean, Orphic, or other mystical background. The theory of forms, in its commitment to the ontological priority of an imperceptible world over a perceptible one, clearly follows the Eleatics, and indeed much of Pre-Socratic natural philosophy.
It remains controversial, within a naive reading of the Platonic corpus as well as in modern debate, both which forms exist and how exactly they are related to perceptible particulars or individuals. At some places in the corpus it seems that moral concepts are the primary type of form: these are the forms most obviously related to the Socratic project of the early dialogues, as well as the sophistic challenges. Elsewhere it seems that craftsman’s artifacts such as beds are the primary model, or mathematical entities such as numbers, or, in the debates of the early Academy as reflected in the late dialogues, the Pseudo-Platonic Definitions and Aristotle’s Metaphysics, biological kinds such as men or horses, or even individuals such as Sokrates. The problematic relationship between the forms and the particulars is examined by Plato himself in Parmenides, where the view that a form is the perfect paradigm of the perceptible individuals, but itself also an individual, is apparently refuted in the so-called ‘‘Third-Man Argument,’’ whereby we are forced to generate yet another level of entity to explain how the form is the same as the perceptible individuals. Alternatively, if the form is not an individual, then it must be somehow identical to all the perceptible individuals, and in that case one appeals to an unclear relationship of ‘‘participation’’ between forms and perceptible objects.
Plato’s late dialogues are often characterized by critique, rejection, or negligence of the theory of forms, as in Parmenides and also in Theaetetus, where questions about knowledge lead anew to aporia. However, since the theory of forms is so variously expressed in various dialogues, and since its clearest expression comes in Phaedo, which in its presentation of the famous intellectual biography of Sokrates as well as his death raises acute questions about what Socraticism is and what persists as its true afterlife, this theory may be taken wrongly, even by Aristotle, as the linchpin of Plato’s views and should be seen more as a hypothetical answer to the Socratic and sophistic problems to which Plato is not committed in any particular way. The ‘‘late’’ dialogues are, then, less likely to be a true philosophical - or even chronological - grouping than the early dialogues: one finds only various radical conflicts with the relatively unified doctrine of the middle dialogues. Thus Timaeus admits a close union between the physical, perceptible world and the forms, which constitute the world on a micro-level. Statesman allows fiction and myth as explanation in a more serious way than early dialogues. Arguments are in general more technical and detailed than in the middle dialogues, perhaps reflecting progress in the Academy, and the Sokrates character is simplified further, sometimes becoming a univocal expounder of doctrine, sometimes, as in Laws, dropped altogether. The later works, too, tend to separate topics or perhaps fields of knowledge more discretely than before - thus, e. g., Laws by contrast with Republic is a program for politics rather than a program of politics, moral psychology, education, and ontology all wrapped together. This trend could show a progressing differentiation of disciplines of ‘‘political’’ knowledge from an original unity, at least in Plato’s view, of the sophistic problem.
Unlike Aristotle, who would pursue and organize virtually all fields of knowledge opened by the Greeks until his time, the interests of Plato and the Academy remained limited to political and ethical issues and their ontological basis, which turned out to involve mathematics. Natural science remained largely excluded, although Plato shows knowledge of contemporary medical theory in Timaeus, and also largely outside the scheme is contemporary research into historical cultural topics such as poetry. Plato certainly knew his Homer, and put forward or criticized theories of interpretation and poetics in many texts (e. g., Ion, Hippias Minor., Protagoras, Republic, Phaedrus), but, as in the case of names in Cratylus or rhetoric in Phaedrus, the point seems to be more a demonstration that most claims to knowledge are insufficient without the right philosophical basis than a serious investigation of these fields in their own right. Incidentally, they allow us intimations of an increasingly diversified intellectual approach in the late fifth and early fourth centuries to the humanist fields that most interested the sophists, Sokrates, and Plato.
After Plato’s death in 348/7, leadership of the Academy was turned over to the Athenian Speusippos, who unlike the metic Aristotle was qualified to own property. A series of successors largely continued and refined the researches into definition, mathematics, and ethics begun by Plato, until 269, when the Academy under Arke-silaos turned to skepticism in a phase known to historians as the Middle Academy.
World History
