Plato (c. 428-c. 347 bc), a Greek philosopher, was one of the most creative and influential thinkers in Western philosophy. Plato is one of the 10 greatest thinkers of all time, according to the American philosopher Will Durant.
LIFE
Plato was born to an aristocratic family in the Athenian democracy.
His father, Ariston, was believed to be descended from the early kings of Athens. Perictione, his mother, was distantly related to the 6th-century bc lawmaker Solon. When Plato was a child, his father died, and his mother married Pyrilampes, who was an associate of the statesman Pericles.
As a young man, Plato had political ambitions, but he became disillusioned with the political leadership in Athens. He eventually became a disciple of Socrates, who had pioneered the search for ethical truth through dialectical questions and answers with anyone claiming to have knowledge. Plato witnessed the execution of Socrates by the Athenian democracy in 399 bc.
Perhaps fearing for his own safety, he left Athens temporarily and travelled to Italy, Sicily, and Egypt.
In 387 bc Plato founded the Academy in Athens, the institution often described as the first European university. It provided a comprehensive curriculum, including such subjects as astronomy, biology, mathematics, political theory, and philosophy. Aristotle became the Academy’s most prominent student.
Pursuing an opportunity to combine philosophy and practical politics, Plato went to Sicily in 367 bc to tutor the new ruler of Syracuse, Dionysius the Younger, in the art of philosophical rule. The experiment failed. Plato made another trip to Syracuse in 361 bc, but again his engagement in Sicilian affairs met with little success.
The concluding years of his life were spent lecturing at the Academy and writing. He died at about the age of 80 in Athens in 348 or 347 bc.
WORKS
Plato’s extant writings are all in the form of dialogues, sometimes framed by a narrator.
They depict philosophical ideas being advanced, discussed, and criticized in the context of a conversation or debate involving two or more people. The earliest ancient collection of Plato’s work includes 35 dialogues and 13 letters. The authenticity of a few of the dialogues and most of the letters has been disputed. The dialogues are conventionally divided by their presumed dates of composition, based on content, style, and internal references.
This yields a useful distinction between the early, middle, and late dialogues.
A. Early Dialogues
The earliest dialogues seem to depict Socrates as Plato saw him at work, questioning leading citizens of Athens about their beliefs.
Several of these dialogues take the same distinctive form. Socrates, encountering someone who seems to know much about a particular ethical topic, professes to be ignorant and seeks enlightenment from the person claiming knowledge. As Socrates questions their definitions, however, it becomes clear that the one reputed to be wise does not really know what he claims to know, and Socrates emerges as the wiser person because he at least knows that he does not know. Such self-knowledge, commanded by the oracle at Delphi by the inscription “know thyself”, is regarded by Socrates as the beginning of wisdom.
Among these dialogues are Charmides (on temperance, also translated as “moderation”), Lysis (on friendship), Laches (on courage), Protagoras (on the structure of the virtues), Euthyphro (on piety), and Book I of The Republic (on justice).
Another distinctive group of dialogues are those that depict the trial and death of Socrates in dramatic form.
These include the Apology, which presents Socrates’s speech in his own defence at his trial on the charges of impiety and corrupting Athenian youth; Crito, in which Socrates examines and rejects his friend Crito’s proposal to help him escape prison and death; and Phaedo, the death scene of Socrates, in which he discusses the theory of forms, the nature of the soul, and the question of immortality.
While the Apology and Crito seem to be early in the sense of depicting the historical Socrates, Phaedo seems to open or at least presage the middle period.
B. Middle Dialogues
Whereas the early dialogues seem to depict Socrates as Plato knew him, the middle and late dialogues seem to represent Plato’s own philosophical development, even though a character named Socrates often leads the discussions.
The middle period is considered the great constructive phase of Plato’s thought, distinguished by the central role of the theory of forms (see below). Exemplars of this stage are the Symposium, a discussion of love as motivating the search for the forms; Timaeus, which uses the forms as models in reconstructing the principles of the cosmos; The Republic, Plato’s longest, most complex, and ambitious work, on the nature of justice in the soul and in the state; and, arguably, as stated above, the Phaedo.
C. Late Dialogues
The works of the later period seem no longer to treat the theory of forms as a central plank in constructing the true philosophy.
Instead, they criticize this theory and discuss a number of other philosophical problems, often abstractly. These works include Theaetetus, which seeks a definition of knowledge and exemplifies the way discussion can help develop ideas; Parmenides (which begins with a critical evaluation of the theory of forms); The Sophist, which discusses being and not-being in order to distinguish the sophist from the philosopher; The Statesman, which analyses the role of the true statesman in the ideal city; Philebus, on the relationship between pleasure and the good; and The Laws, Plato’s unfinished last work, which proposes the laws needed to mediate between human irrationality and rational knowledge.
THEORY OF FORMS
At the heart of Plato’s constructive philosophy is his theory of forms, or ideas. This notion underpins his view of knowledge, his ethical theory, his psychology, his concept of the state, and his perspective on art.
A. Theory of Knowledge
Plato’s theory of forms and his theory of knowledge are interrelated.
Influenced by Socrates, Plato sought to understand the nature of the genuine knowledge that his teacher had professed to lack. He held that such knowledge must be correlated with the nature of the real: as the fully real is fixed, permanent, and unchanging, so must knowledge be certain and immune to revision or correction. Only such knowledge can be teachable.
In his middle period he identified knowledge with knowledge of certain objects that are most truly real in this sense, and which underlie the mutable and misleading world of appearances. These are the forms.
It follows that sense experience and perception are worthless as routes to knowledge; they inform us only of the appearances or “phenomena”, not of the real essences. The sole route to knowledge is reason, the faculty of perceiving intelligible objects as contrasted with the senses, which perceive physical objects. The famous images of Sun, line, and cave that Plato uses in The Republic express this understanding of knowledge.
The image of the Sun suggests that as the Sun is the condition for the perceptibility of physical objects, so the form of the Good is the condition of the intelligibility of the forms; in other words, he implies that a notion of value is pervasive and fundamental to reality.
B. Nature of Forms
The theory of forms applies centrally to moral and ethical notions.
Nonetheless, the best way to begin to understand the forms is to compare them with mathematical entities, exactly as Plato does in the image of the line in The Republic. A circle, for instance, is a plane figure composed of a series of points, all of which are equidistant from a given point, yet none of which occupy any space themselves. No one has ever seen an ideal circle; one only ever sees approximations of the mathematical version, since all physical circles do occupy some space. An ideal circle would be perfect, timeless, and the model for the circularity of all ordinary circles.
In the same way, the forms—such as Beauty and Good—are perfect, timeless entities. Ordinary physical objects resemble (“participate in”) the forms, and thereby gain whatever reality they have. In this sense, the postulation of forms belongs both to epistemology (the study of knowledge) and ontology (the study of what there is).
Most of Plato’s arguments for and about the existence of forms move from the instability and relative qualities of physical objects to the claim that some stable objects must exist as benchmarks for those that are comparative and changing. Occasionally, as in Book X of The Republic, he seems to suggest that every universal term (such as “bed” or “table”) must correspond to a form.
However, this suggestion is out of place in the bulk of the discussion of forms.
POLITICAL THEORY AND ETHICS
The Republic, Plato’s major political work, is concerned with the question of justice.
Starting with the question “Does justice pay for the individual, apart from any external rewards?”, it argues that justice in the soul is linked to justice in the city. Both soul and city have three analogous parts: a desiring part; a spirited part (something like the will); and a rational part. Justice involves each part carrying out its own proper function; Plato argues that this means that the two non-rational parts must be ruled by the rational part. Far from being a mere analogy, the relation between soul and the city turns out to mean that the two lower classes in the city must be ruled by the highest class, the philosophers.
They alone can use their reason to acquire knowledge of the forms.
The political structure of the just city would thus depend on a thorough educational programme, which selects the potential philosophers on the basis of merit, without regard to class or gender, and trains them ultimately to know and love the forms, through which each person progresses to his or her maximal level of ability. Such an education must begin by training the appetites and spirit to accede to the rule of reason, and so the earlier stages involve music and gymnastics, which seek to harmonize the passions. The later stages of education use mathematics as a gateway to the forms.
Once the philosophers are selected, their autocratic rule in the light of reason must be safeguarded from corruption. Therefore, they are to be deprived of private property and families, and forced to pay attention to civic affairs instead of only contemplating the forms. Such drastic measures alone can ensure that their rule is for the sake of the city as a whole and not for their private interests.
Nevertheless, Plato is not sanguine about the stability of such a regime; he foresees a failure of the philosophers to apply their ideal knowledge and the decline of regimes that would then follow.
In the absence of an ideal city, the individual can only seek to know the form of the Good and guide his or her actions by that knowledge, which Plato compares to the patterns of the stars.
ART
Plato’s view of art involved a deep tension. On the one hand, his works are celebrated as great literature. On the other hand, he was acutely aware that writers such as Homer were rivals to his vision of the rational society, since art could appeal to irrational emotions that it could develop to subvert rather than support reason.
He therefore insisted in The Republic that artists should be censored so that their art served the purposes of justice, reason, and religion. At his most critical, he argued that whereas physical objects (such as flowers) are one step away from the reality of the forms (such as Beauty), pictures and artistic representations of the flowers are two steps away from reality.
Artists are therefore estranged from knowledge, even though they may be inspired by a kind of madness with which Socrates and Plato were not unfamiliar.
INFLUENCE ON RELIGIONS
Plato’s influence on the later history of philosophy has been monumental.
His Academy continued in existence, though purveying very different teachings, until ad 529, when it was closed by the Byzantine emperor Justinian I for conflicting with Christianity. Plato’s impact on Jewish thought is apparent in the work of the 1st-century Alexandrian philosopher Philo Judaeus. Neoplatonism, founded by the 3rd-century philosopher Plotinus, transformed Platonism in terms of Christianity and Christianity in terms of Platonism.
This Christian engagement with Plato was continued by the theologians Clement of Alexandria, Origen, and St Augustine. Platonic ideas were also crucial to medieval Islamic thought, and many dialogues were preserved in Arabic, then re-translated into Latin and Greek during the Renaissance.
A focus of Platonic influence then became the Florentine Academy, founded in the 15th century near Florence. Under the leadership of Marsilio Ficino, members of the Academy studied Plato in the original Greek, although Plato’s thought never exercised the institutional authority of Aristotle’s, who for his part dominated the scholastic movement. In England, Platonism was revived in the 17th century by Ralph Cudworth and others who became known as the Cambridge Platonists.
British thinkers engaged with Plato in the 19th century as a source for Victorian values and beliefs in education. In the 20th century, figures such as Karl Popper and Hannah Arendt interrogated Plato to see how far his ideas prefigured totalitarianism.
Reflecting on this remarkable intellectual history, Alfred North Whitehead concluded that the history of philosophy is but “a series of footnotes to Plato”.