Plato (427–347 BC)
Authors: Schofield Malcolm 
Published: September 2018

Plato was an Athenian Greek of aristocratic family, active as a philosopher in the first half of the fourth century bc. He was a devoted follower of Socrates, as his writings make abundantly plain. Nearly all are philosophical dialogues – often works of dazzling literary sophistication – in which Socrates takes centre stage. Socrates is usually a charismatic figure who outshines a whole succession of lesser interlocutors, from sophists, politicians and generals to docile teenagers. The most powerfully realistic fictions among the dialogues, such as Protagoras and Symposium, recreate a lost world of exuberant intellectual self-confidence in an Athens not yet torn apart by civil strife or reduced by defeat in the Peloponnesian War.
Some of Plato’s earliest writings were evidently composed in an attempt to defend Socrates and his philosophical mission against the misunderstanding and prejudice which – in the view of his friends – had brought about his prosecution and death. Most notable of these are Apology, which purports to reproduce the speeches Socrates gave at his trial, and Gorgias, a long and impassioned debate over the choice between a philosophical and a political life. Several early dialogues pit Socrates against practitioners of rival disciplines, whether rhetoric (as in Gorgias) or sophistic education (Protagoras) or expertise in religion (Euthyphro), and were clearly designed as invitations to philosophy as well as warnings against the pretensions of the alternatives. Apologetic and protreptic concerns are seldom entirely absent from any Platonic dialogue in which Socrates is protagonist, but in others among the early works the emphasis falls more heavily upon his ethical philosophy in its own right. For example, Laches (on courage) and Charmides (on moderation) explore these topics in characteristic Socratic style, relying mostly on his method of elenchus (refutation), although Plato seems by no means committed to a Socratic intellectualist analysis of the virtues as forms of knowledge. That analysis is in fact examined in these dialogues (as also, for example, in Hippias Minor).
In dialogues of Plato’s middle period like Meno, Symposium and Phaedo a rather different Socrates is presented. He gives voice to positive positions on a much wider range of topics: not just ethics, but metaphysics and epistemology and psychology too. And he is portrayed as recommending a new and constructive instrument of inquiry borrowed from mathematics, the method of hypothesis. While there are continuities between Plato’s early and middle period versions of Socrates, it is clear that an evolution has occurred. Plato is no longer a Socratic, not even a critical and original Socratic: he has turned Socrates into a Platonist.
The two major theories that make up Platonism are the theory of Forms and the doctrine of the immortality of the soul. The notion of a Form is articulated with the aid of conceptual resources drawn from Eleatic philosophy. The ultimate object of a philosopher’s search for knowledge is a kind of being that is quite unlike the familiar objects of the phenomenal world: something eternal and changeless, eminently and exclusively whatever – beautiful or just or equal – it is, not qualified in time or place or relation or respect. An account of the Form of Beautiful will explain what it is for something to be beautiful, and indeed other things are caused to be beautiful by their participation in the Beautiful. The middle period dialogues never put forward any proof of the existence of Forms. The theory is usually presented as a basic assumption to which the interlocutors agree to subscribe. Plato seems to treat it as a very general high-level hypothesis which provides the framework within which other questions can be explored, including the immortality of the soul. According to Phaedo, such a hypothesis will only stand if its consequences are consistent with other relevant truths; according to Republic its validity must ultimately be assured by its coherence with the unhypothetical first principle constituted by specification of the Good.
The Pythagorean doctrine of the immortality of the soul, by contrast, is something for which Plato presents explicit proofs whenever he introduces it into discussion. It presupposes the dualist idea that soul and body are intrinsically distinct substances, which coexist during our life, but separate again at death. Its first appearance is in Meno, where it is invoked in explanation of how we acquire a priori knowledge of mathematical truths. Socrates is represented as insisting that nobody imparts such truths to us as information: we work them out for ourselves, by recollecting them from within, where they must have lain untapped as latent memory throughout our lives. But innate forgotten knowledge presupposes a time before the soul entered the body, when it was in full conscious possession of truth. Phaedo holds out the promise that the souls of philosophers who devote their lives to the pursuit of wisdom will upon death be wholly freed from the constraints and contaminations of the body, and achieve pure knowledge of the Forms once again.
Republic, Plato’s greatest work, also belongs to this major constructive period of his philosophizing. It gives the epistemology and metaphysics of Forms a key role in political philosophy. The ideally just city (or some approximation to it), and the communist institutions which control the life of its elite governing class, could only become a practical possibility if philosophers were to acquire political power or rulers to engage sincerely and adequately in philosophy. This is because a philosopher-ruler whose emotions have been properly trained and disciplined by Plato’s reforming educational programme, and whose mind has been prepared for abstract thought about Forms by rigorous and comprehensive study of mathematics, is the only person with the knowledge and virtue necessary for producing harmony in society. Understanding of Forms, and above all of the Good, keystone of the system of Forms, is thus the essential prerequisite of political order.
It remains disputed how far Plato’s vision of a good society ruled by philosopher- statesmen (of both sexes) was ever really conceived as a blueprint for practical implementation. Much of his writing suggests a deep pessimism about the prospects for human happiness. The most potent image in Republic is the analogy of the cave, which depicts ordinary humanity as so shackled by illusions several times removed from the illumination of truth that only radical moral and intellectual conversion could redeem us. And its theory of the human psyche is no less dark: the opposing desires of reason, emotion and appetite render it all too liable to the internal conflict which constitutes moral disease.
While Republic is for modern readers the central text in Plato’s œuvre, throughout much of antiquity and the medieval period Timaeus was the dialogue by which he was best known. In this late work Plato offers an account of the creation of an ordered universe by a divine craftsman, who invests pre-existing matter with every form of life and intelligence by the application of harmonious mathematical ratios. This is claimed to be only a ’likely story’, the best explanation we can infer for phenomena which have none of the unchangeable permanence of the Forms. None the less Timaeus is the only work among post-Republic dialogues, apart from a highly-charged myth in Phaedrus, in which Plato was again to communicate the comprehensive vision expressed in the Platonism of the middle period dialogues.
Many of these dialogues are however remarkable contributions to philosophy, and none more so than the self-critical Parmenides. Here the mature Parmenides is represented as mounting a powerful set of challenges to the logical coherence of the theory of Forms. He urges not abandonment of the theory, but much harder work in the practice of dialectical argument if the challenges are to be met. Other pioneering explorations were in epistemology (Theaetetus) and philosophical logic (Sophist). Theaetetus mounts a powerful attack on Protagoras’ relativist theory of truth, before grappling with puzzles about false belief and problems with the perennially attractive idea that knowledge is a complex built out of unknowable simples. Sophist engages with the Parmenidean paradox that what is not cannot be spoken or thought about. It forges fundamental distinctions between identity and predication and between subject and predicate in its attempt to rescue meaningful discourse from the absurdities of the paradox.
In his sixties Plato made two visits to the court of Dionysius II in Sicily, apparently with some hopes of exercising a beneficial influence on the young despot. Both attempts were abysmal failures. But they did not deter Plato from writing extensively on politics in his last years. Statesman explores the practical knowledge the expert statesman must command. It was followed by the longest, even if not the liveliest, work he ever wrote, the twelve books of Laws, perhaps still unfinished at his death.