Platonism
What changes does not exhaust the real: seeking the that make things intelligible, and that orient thought toward the Good.
387 BCE – 529
A tradition issuing from the Academy, the school founded near Athens around 387 BCE and which lasted several centuries. Heir to Socrates and adversary of the sophists, Plato seeks, against their relativism and the Heraclitean flux, a stable foundation for knowledge and justice, which he unfolds in dialogues, the , the , the , where dialectical reasoning serves as method. After the early Academy, the tradition was renewed in the Neoplatonism of in the third century, then died out with the closing of the Athenian school in 529. Taken up by and the Church Fathers, it lastingly shaped Western metaphysics, theology and mysticism, and remains, in Whitehead's phrase, the horizon to which all later philosophy is a series of footnotes.
The Beautiful, the Just, the Circle exist in themselves, separate from the things that imitate them: these are more real than the sensible, not mere names nor forms immanent in things.
The sensible world is but the shadow of the intelligible world: what we take for reality is only a play of copies, and the philosopher alone leaves the cave for the light of the Forms.
To know is not to gather sensations but to recollect: through , the soul recovers within itself the Forms it contemplated before birth.
The supreme principle, the Good then the One, stands : source of all reality, it is itself none of the things of which it is the cause.
The immortal soul, akin to the Forms, is the true self; the body is but a tomb from which one must loosen oneself to contemplate truth.
Justification
The starting point is a paradox of learning set out in the Meno: one can search neither for what one already knows nor for what one is wholly ignorant of, being then unable to recognise it. cuts the dilemma: having contemplated the Forms before birth, the soul discovers nothing absolutely new but remembers, as the slave of the Meno recovers a theorem under the mere guidance of questions. Platonism is thus a consistent rationalism (the doctrine that makes reason, not the senses, the source of true knowledge): since sensation bears only on the changing and yields mere opinion, true knowledge cannot come from the senses but from reason turning back upon itself. This is the exact reverse of empiricism, for which nothing is in the intellect that was not first in the senses.
Plato, Meno, 80d-86c, recollection · Plato, Republic, 509d-511e, the divided line
Justification
Against sophistic relativism, Platonism holds that a true science, epistēmē (stable scientific knowledge of the true, opposed to mere opinion, doxa), of the Forms is attainable, distinct from mere opinion. The wise can reach stable and certain knowledge of what is eternal, a markedly stance in the classical sense.
Plato, Theaetetus, 201d-210a, knowledge and opinion · Plato, Republic, 477a-480a
Justification
The argument starts from the object of knowledge and of definition: science bears on what is one, stable and self-identical, yet no sensible object is so, coming to be, changing and perishing. The one over the many therefore demands a distinct reality, the same Beautiful in which all beautiful things share. Platonism then takes the decisive step will refuse: it this Form from things rather than lodging it in them as an immanent form. This sets it apart both from nominalism, for which the universal is only a name, and from Aristotelian hylomorphism.
Plato, Republic, VI-VII
Justification
The priority of essence follows from the separation of the Forms: if the Form exists in itself, outside time and outside things, then the «what it is» precedes by right any singular existence, which merely imitates it. A thing is what it is only by participation (methexis, the relation by which the sensible derives its being from the intelligible) in a model it neither grounds nor alters. Essence is thus neither abstracted from cases by the mind nor posterior to individuals: it is prior and causal. This is essentialism at its source, whose order existentialism will later reverse.
Plato, Republic, books VI-VII · Plato, Phaedo, 100b-102a
Justification
The Platonic sovereign good is assimilation to the divine through the soul's ascent toward the Good, which presupposes the order of the virtues and the justice of the soul. Happiness, , follows from it, but is subordinated to a moral and contemplative perfection that requires turning one's gaze away from the sensible.
Plato, Republic, book IV, on the justice of the soul · Plato, Theaetetus, 176a-b, assimilation to god
Justification
The argument from kinship draws its conclusion from the metaphysics of the Forms: what knows the intelligible must resemble it, and the soul grasps realities that are simple, invisible and unchanging; it is therefore itself of that nature, and what is simple cannot be decomposed or perish. The body, by contrast, through its needs and passions, blurs contemplation and chains the soul to the sensible: hence the image of the body as the tomb of the soul (sōma/sēma). The true self is thus the soul, not the compound. This rules out in advance the thesis, ascribed to a Pythagorean in the , that would make the soul a mere attunement of the body, perishing with it.
Plato, Phaedo
Justification
Platonism orders the soul in three tiers, where reason must govern the appetites with the help of spirit: left to themselves, the desires of the body enslave and trouble. Wisdom consists in mastering them and in sublimating eros, in turning its force away from the sensible toward intelligible Beauty and the Good. A severe sorting of desires, then, leaning toward their transcendence more than their satisfaction.
Plato, Republic, IV and IX · Plato, Symposium; Phaedrus
Justification
Platonism affirms the immortality of the soul, argued in the from its kinship with the Forms and its simple, indissoluble nature. Death is but the separation of soul and body, and the philosopher rehearses it throughout his life.
Plato, Phaedo, 64a, 78b-80b, death as practice · Plato, Republic, 608d-611a, the immortality of the soul
Justification
Platonic asceticism rests on the image of the body as the tomb of the soul (sōma/sēma) and on distrust of sensible pleasures, which chain the soul to becoming and hamper its ascent toward the intelligible. Purification consists in detaching oneself from the body as far as possible.
Plato, Phaedo, 64c-67b, purification · Plato, Gorgias, 493a, the body as tomb
Justification
Platonism is fundamentally teleological (explaining beings by the end, the telos, toward which they tend): the world is ordered by the Demiurge for the best, after the model of the Forms, and everything tends toward the Good as toward its end. Human existence finds its meaning in this orientation of the soul toward the principle that orders the whole.
Plato, Timaeus, 29d-30c, the ordering of the world · Plato, Republic, 505a-509c, the Good as end
Justification
The Platonic self is a substance (a reality subsisting in itself, the permanent bearer of identity): the soul is a simple, immaterial and immortal reality, distinct from the body and akin to the . It constitutes the person's true identity, the body being only a provisional garment from which it separates at death.
Plato, Phaedo, 78b-80b, the simplicity of the soul · Plato, Republic, 611b-612a
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Justification
Platonism holds suffering to be potentially purifying: just punishment heals the soul, and the conversion toward the intelligible demands a painful tearing away from the sensible world and the pleasures of the body. Ordeal separates the soul from what enslaves it and brings it closer to the true, which gives it a value that an easy life ignores.
Plato, Gorgias; Phaedo · Plato, Republic, VII
Justification
Against the relativism of the sophists, for whom man is the measure of all things, Platonism grounds values in objective realities: the of the Just, the Good and the Beautiful exist in themselves and hold universally, independent of conventions and opinions. Morality has a real metaphysical foundation.
Plato, Theaetetus, 152a, refutation of Protagoras · Plato, Republic, 504d-509c, the Form of the Good
Justification
Platonic eros is desire born of lack: child of Poros and Penia, it seeks to possess what it wants, the beautiful and the good. From the beauty of bodies the lover ascends by degrees to the , along the ladder of the Symposium.
Plato, Symposium, 201d-212c, speech of Diotima · Plato, Phaedrus, 244a-257b
Justification
Platonic ethics is a virtue ethics (a morality centred on the agent's character and excellence rather than on the rule or the consequence): to act well is to realize justice within oneself, understood as the harmony of the , each part performing its proper function under the rule of reason. Virtue is ultimately reducible to knowledge of the Good.
Plato, Republic, book IV, 441c-444e, the justice of the soul · Plato, Meno, 87c-89a, virtue as knowledge
Justification
Platonism is epistocratic (reserving power for those who hold knowledge): power should fall to those who know, the philosopher-kings (the philosopher-guardians of the just city, alone fit to govern), alone able to contemplate the and so to govern justly. Democracy, which entrusts decisions to the opinion of the ignorant multitude, is judged corrupting.
Plato, Republic, 473c-474c, the philosopher-king · Plato, Republic, book VIII, 555b-562a, critique of democracy
Justification
The Republic sketches an ideal city (politeia, the just constitution ruled by the model of the Forms), a paradigmatic model of justice founded on the Forms rather than on existing political experience. This utopianism (the claim to rule the city by a perfect order conceived a priori) assumes that the organization of the city should be ruled by a perfect intelligible order, even at the cost of clashing with facts.
Plato, Republic, books II-V, the just city · Plato, Republic, 472b-473b, the city as paradigm
Justification
Reality is measured by the stability of being: what stays self-identical is more real than what wavers between being and non-being. Now the sensible, always in becoming, has only a borrowed being, held by participation (the relation by which the sensible derives its being from the intelligible) in the intelligible that grounds it. Hence a hierarchical dualism (the division of the real into two orders, the intelligible and the sensible, soul and body), two worlds but not on a par: the sensible is the shadow, the intelligible the source. The allegory of the cave turns this into an argument about the human condition, prisoner of copies until it has converted its gaze. Against materialism, it is not the body that grounds the soul, but the intelligible that grounds the sensible.
This dwelling is the prison; the light of the fire in it is the sun; and the upward journey is the ascent of the soul into the intelligible region.Republic, VII, 517b
Plato, Republic, 514a-517a, allegory of the cave · Plotinus, Enneads, V
Justification
The argument proceeds by a solar analogy: just as the sun lets things be seen and grow without being itself either sight or the things, the Good lets the Forms be known and be, without being itself a Form among them. A principle that makes being possible cannot then rank among the beings it grounds: it must be set . radicalises this step by making the One the origin from which all proceeds by emanation, ineffable because prior to every determination. This of the ground sets Platonism apart from the divine of the Stoics, mixed into the matter of the world.
The Good is not being, but still beyond being, surpassing it in dignity and power.Republic, VI, 509b
Plato, Republic, 509b, the Good beyond essence · Plotinus, Enneads, VI, 9, on the One
Justification
What thinks cannot be of the same nature as what is thought from without: the soul knows the immaterial Forms, it moves itself and outlasts the body's states, traits no arrangement of matter could produce. Consciousness thus belongs to an order other than the sensible, prior to and independent of it, not to a bodily configuration that would generate it. Platonism thereby refuses in advance any reduction of mind to matter, where the Stoics will make the soul a corporeal breath.
Plato, Phaedo; Phaedrus
Justification
Platonism holds an objective beauty: the is a reality in itself, eternal and self-identical, of which sensible beauties are only pale participations. Beauty does not depend on the beholder's taste but on an essence that reason can contemplate.
A beauty that always is, neither coming to be nor passing away, neither increasing nor diminishing; nor again beautiful in one part and ugly in another.Symposium, 211a
Plato, Symposium, 210a-211d, the ladder of beauty · Plato, Greater Hippias
Justification
Platonism is intellectualist (the doctrine that subordinates the passions to reason and makes knowledge the condition of acting well): in the image of the winged chariot, a figure of the , reason is the charioteer who must guide and master the two horses, spirit and appetite. The passions are not evil in themselves, but they have worth only when disciplined and subjected to the rule of reason.
Plato, Phaedrus, 246a-254e, the winged chariot · Plato, Republic, book IV, 439d-441c
Justification
For Platonism, art is mimēsis (imitation, a copy of a copy of the real): the painter copies the sensible object, itself a copy of the Form, so that the work stands at three removes from truth, twice removed from the real. This is why Plato distrusts the poets and submits them to censorship in the just city.
Plato, Republic, book X, 595a-602c, art as imitation · Plato, Republic, book III, 386a-398b
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Justification
Platonism posits an ordering divine principle: the Demiurge (the divine craftsman of the Timaeus who orders the world after the model of the Forms) of the Timaeus shapes the world after the model of the Forms, and Plotinus' One is the source from which all proceeds. This theistic orientation, not that of a personal god in Plato, prepares the Christian theology of Augustine.
Plato, Timaeus, 28a-30c, the Demiurge · Plotinus, Enneads, V, 1-2; Augustine, Confessions, VII
Justification
Owing to objective beauty and the hierarchy of goods, Platonism implies a hierarchy of taste: not all pleasures and objects are of equal worth, and the pleasures of the intellect, ordered to the true and the beautiful, are objectively superior to those of the body. The gradation follows the ladder leading from the sensible to the intelligible.
Plato, Philebus, 51a-53c, the hierarchy of pleasures · Plato, Republic, 580d-587a, pleasures compared