A Psychiatrist and Philosopher Explains Plato’s Theory of Forms and Why It Lies at the Heart of Plato’s Philosophy
‘The eye of the soul must be turned around.’
By Dr Neel Burton — Psychiatrist, philosopher, and wine writer; Fellow of Green Templeton College, University of Oxford; author of over twenty books.
Plato’s Forms have profoundly shaped Western philosophy, psychology, and theology.
In On the Genealogy of Morality (1887), Nietzsche calls Plato ‘the sincerest advocate of the beyond, the great slanderer of life’. For Nietzsche, Plato inaugurates a metaphysical split between truth and appearance that systematically devalues the world we live in.
Yet the dichotomy between truth and appearance has deeper roots in pre-Socratic philosophy. Just as Plato leant upon Heraclitus’ doctrine of flux for his conception of the sensible world (the world as we see it), so he leant upon Parmenides’ unity for his conception of the intelligible world (the world as we think it), which he rendered as the immutable realm of the Forms.
The Genesis of the Forms
Plato’s authorship spanned some fifty years, from the death of Socrates in 399 BCE to his own death in c. 348 BCE. He is traditionally credited with 35 dialogues, although around ten of these are spurious or of doubtful authenticity. Today, the dialogues are often classified into early, middle, and late periods, based on their presumed order of composition.
This matters because the Theory of Forms does not appear fully formed, but gradually emerges from Plato’s development of Socratic questioning into a more systematic metaphysics.
The early dialogues are relatively short and accessible. They are sometimes referred to as the Socratic dialogues because they present a more historically faithful Socrates, typically engaged in ethical investigations of temperance, courage, or friendship with youths, friends, or supposed experts.
From these beginnings, Plato gradually develops his own philosophical system, including the Theory of Forms, which becomes central in middle dialogues such as Phaedo, Symposium, and Republic. In these longer and more literary works, Socrates is less the historical figure and more a mouthpiece for Plato’s developing doctrines. He is accordingly more didactic, putting forward positive theories rather than simply questioning and refuting. Other middle-period doctrines that are unlikely to be Socratic include the Theory of Recollection, the Theory of Reincarnation, and the Theory of the Tripartite Soul—each closely connected to the Forms.
The Forms in the Phaedo
The Phaedo is named after Phaedo of Elis, a follower of Socrates who was present at his death. It is the dialogue in which Plato most explicitly develops the Theory of Forms, although without yet offering a systematic exposition.
It also assumes familiarity with the Meno and the Theory of Recollection, which the Phaedo builds upon.
In the Phaedo, once titled On the Soul, Socrates offers four arguments for the immortality of the soul, among them arguments that draw on recollection and the Theory of Forms. The apparent immortality of the soul enables Socrates to remain calm in the face of his impending execution and provides a metaphysical foundation for the life of philosophy. The dialogue ends with a myth of the afterlife and, of course, the dramatic drinking of hemlock.
Socrates argues that what is compounded is dissoluble, whereas what is uncompounded is indissoluble and therefore unchanging. The Forms (for instance, Beauty itself), which are unchanging, are uncompounded. Their particulars (for instance, a beautiful horse), which are in a constant state of composition and decay, are compounded.
Particulars are apprehended by the senses, but the Forms can only be apprehended by the mind. Since the soul is not apprehended by the senses, Socrates argues that it is akin to the Forms and therefore not subject to dissolution in the same way as bodily things.
The embodied soul uses the body as an instrument of perception, but what the body perceives is in perpetual flux, so that the soul is often drawn into confusion. When the soul turns away from the body and contemplates itself, it moves toward the realm of the unchanging and approaches wisdom.
Upon death, not all souls undergo the same fate. The soul of the philosopher, being least attached to the body, is able to dwell in the realm of the unchanging, where it ‘lives in bliss and is released from the error and folly of men, their fears and wild passions and all other human ills’. Souls that are more attached to bodily desire remain bound to the cycle of embodiment.
Socrates also suggests that Forms explain the deep structure of reality: things are beautiful because they participate in the Form of Beauty, two is two because it participates in the Form of Duality, and so on. A thing that participates in a Form may also participate in other related Forms. For instance, three pencils participate in the Form of Threeness and also in the Form of Oddness. However, opposite Forms such as Even and Odd cannot admit of each other in the same respect. In this way, the soul—being essentially alive—cannot admit its opposite, death, and is therefore closely bound to immortality.
The Symposium: Love as the Engine of Wisdom
In the Symposium, Socrates recounts the teaching of the priestess Diotima on the proper ascent to the love of beauty. A young person begins by loving one beautiful body. He then realises that all beautiful bodies share something in common, and that it is irrational to be attached to only one.
From there, love expands to all beautiful bodies, then to the beauty of the soul, then to beautiful practices and forms of knowledge. Eventually, the lover ascends to the vision of Beauty itself, no longer tied to any particular instance of it.
At the highest stage of this ‘ladder of love’, the soul apprehends Beauty itself rather than its appearances. In doing so, it comes as close as possible, within human life, to something stable and eternal.
The Republic: The Form of the Good
In Book VI of the Republic, in the context of educating the philosopher-kings, Plato introduces the elusive Form of the Good. It is by apprehending the Good that the philosopher becomes fit to rule, since it is the source of intelligibility and value in all things.
Because the Good cannot be directly defined, Socrates conveys it indirectly through three famous metaphors: the sun, the divided line, and the cave (discussed in a separate article).
Legacy of the Forms
In the Phaedo, the Theory of Forms is presented as the most plausible account of reality, without sustained criticism. In later dialogues, Plato becomes more self-critical; in the Parmenides, the Theory of Forms is subjected to a severe and systematic critique.
However arresting it may be, the Theory of Forms is never fully finalised. It becomes less prominent in the late dialogues and increasingly problematised from within.
Part of the pleasure of reading Plato is that he is thinking with us rather than simply instructing us. The dialogues are not dogmatic systems but staged explorations of philosophical possibility.
In any case, our interest in the Theory of Forms is less in its strict logical coherence than in its enduring influence. The Phaedo helped establish a set of deep dualities that have shaped much of Western thought: soul and body, mind and matter, reason and sense perception, reality and appearance, good and evil, heaven and earth.
In later Western traditions, these distinctions were often intensified into moral and metaphysical hierarchies. The body is frequently associated with limitation, desire, and error, while the soul or intellect is associated with truth and transcendence. Yet this inheritance is uneven: other traditions, including various strands of Eastern philosophy and practice, place less emphasis on such sharp oppositions and more on integration, discipline, or transformation within embodied life.
At the same time, Plato’s vision is not simply world-denying. The discipline of detachment in the Phaedo and the Symposium also points toward a kind of freedom from compulsion—whether read metaphysically, ethically, or psychologically.
Plato’s ladder of love: from the beauty of the body to Beauty itself.
By Dr Neel Burton — Psychiatrist, philosopher, and wine writer; Fellow of Green Templeton College, University of Oxford; author of over twenty books.
Essay substantially revised on 19 August 2026.
The Man Who Coined ‘Platonic Love’
After the fall of the Western Roman Empire, the knowledge of Greek was lost in the West. In around 321 CE, the philosopher Calcidius had published a Latin translation of the first part of Plato’s Timaeus, which for almost 800 years remained the only substantial section of Plato available to the Latin West.
Fortunately, the study of Plato continued in the Byzantine Empire and Islamic world. At the 1438-39 Council of Florence, the Byzantine scholar George Gemistos Plethon reintroduced Plato to the West as part of a failed attempt to repair the Great Schism between the Eastern and Western Church and present a united front to the Ottoman Empire (Constantinople finally fell to the Ottomans in 1453).
While in Florence, Gemistos Plethon made an impression on the banker, politician, and patron of the arts Cosimo de’ Medici, who had, among others, commissioned the David of Donatello, the first freestanding male nude sculpture since antiquity. He persuaded Cosimo to establish an institute and informal discussion group, now known as the Platonic Academy of Florence, which, under Cosimo’s protégé Marsilio Ficino, went on to translate all of Plato’s extant works into Latin. This, in turn, ignited and inflamed the humanist Renaissance.
It is also Ficino who coined the term ‘Platonic love’ (amor platonicus), which first appears in a letter that he wrote to Alamanno Donati in 1476. In 1492, he published a series of Platonic love letters to Giovanni amico mio perfettissimo (‘Giovanni my most perfect friend’), the poet Giovanni Cavalcanti.
Today, ‘Platonic love’ means what Ficino, who lived in a much more closeted time, intended it to mean: a close relationship from which sex and sexual desire are absent, or not acted upon. Whatever it was, Ficino presented his love for Giovanni not as sexual but as elevating. But Plato’s vision of love is a lot more radical and ambitious than Ficino’s idea of it. We glimpse it in dialogues such as the Greater Alcibiades, in the relationship between Socrates and Alcibiades, and in the Phaedrus, in the relationship between Socrates and Phaedrus. It also appears in other dialogues such as the Lysis, the Meno, and the Charmides, in which Socrates sees inside Charmides’ cloak and ‘catches fire’. Then, in the Symposium, Plato literally spells it out.
Socrates and Alcibiades
Socrates was remarkably full-blooded for an ascetic philosopher. In Xenophon’s Symposium, he says, ‘For myself I cannot name the time at which I have not been in love with someone.’ By all accounts, his greatest love was with the famously handsome Alcibiades (450-404 BCE), who was by some twenty years his junior.
In 432, Socrates and Alcibiades fought in the Battle of Potidaea, where the middle-aged plebeian and the young aristocrat became unlikely tent mates. In his Life of Alcibiades, Plutarch relates that ‘all were amazed to see [Alcibiades] eating, exercising, and tenting with Socrates, while he was harsh and stubborn with the rest of his lovers’. In Plato’s Symposium, Alcibiades reports that Socrates singlehandedly saved his life at Potidaea and, even after that, let him keep the prize for valour.
Plato’s Symposium is set in 416, some 16 years after the Battle of Potidaea, and just before the fateful Sicilian Expedition that led Alcibiades to defect to Sparta. The setting is a drinking party hosted by the playwright Agathon. After each of the guests, including Socrates, has made a speech in praise of love, a drunken Alcibiades stumbles in supported by a flute-girl. When Alcibiades entreats everyone to drink and match him in his drunkenness, the other guests object to ‘drinking as if we were thirsty’ and suggest that Alcibiades instead make a speech in praise of Socrates.
Alcibiades says that Socrates always makes him admit that he is wasting his time on his political career while neglecting his several shortcomings. So he tears himself away from him as from the song of a siren and once again lets his love of popularity get the better of him. Socrates may look like a satyr and pose as ignorant, but, like the busts of Silenus (the tutor of Dionysus), he hides bright and beautiful images of the gods within him. Attracted by his wisdom, he tried several times to seduce him, but each time without success. Eventually, he turned the tables round and began to chase the older man, inviting him to dinner and on one occasion persuading him to stay the night. He then lay beside him and put it to him that, of all his lovers, he was the only one worthy of him, and he would be a fool to refuse him any favours if only he could make him into a better man.
Socrates replied in his usual, ironical manner:
Alcibiades, my friend, you have indeed an elevated aim if what you say is true, and if there really is in me any power by which you may become better; truly you must see in me some rare beauty of a kind infinitely higher than any which I see in you. And therefore, if you mean to share with me and to exchange beauty for beauty, you will have greatly the advantage of me; you will gain true beauty in return for appearance—like Diomedes, gold in exchange for brass.
After this, Alcibiades crept under the older man’s threadbare cloak and held him all night in his arms—but in the morning arose ‘as from the couch of a father or an elder brother’.
All this, says Alcibiades, took place before Potidaea. But how much of his drunken account is true, and how much invented by Plato to rehabilitate the reputation of Socrates? Socrates—remember—was put to death, in part, for ‘corrupting the youth’.
In the little-known Alcibiades of Aeschines, Socrates relates a conversation that he once had with Alcibiades. Socrates tells his companion that, if he was at all able to improve Alcibiades, this was not through any knowledge or art that he possessed, but only by the force of the love (eros) that the enfant terrible had aroused in him.
The relationship turns the conventional hierarchy of beauty on its head. Alcibiades possesses youth and physical beauty, not to mention birth and position, but it is the old, ugly, and plebeian Socrates who possesses the inner beauty that Alcibiades, when he dares, most desires.
Socrates and Phaedrus
The ostensible theme of Plato’s Phaedrus is love and pederasty, and the dialogue is full of flirtatious banter and sexual innuendo. Socrates persuades the young Phaedrus to pull out the speech on love that he is hiding under his cloak… The grass on which they lie down to read the speech is ‘like a pillow gently sloping to the head’ … After Phaedrus has read the speech, Socrates says, ‘the effect on me was ravishing. And this I owe to you Phaedrus, for I observed you while reading to be in an ecstasy … and like you, my divine darling, I became inspired with a phrenzy.’
But although the Phaedrus appears, especially at first, to be about love, it is more properly about the education of the soul, which might be led to wisdom by the power of love or dialectic (reasoned discourse), although not, as Socrates argues, oratory (rhetoric) or the written word. Just as the Phaedo used to be called, On the Soul, so the Phaedrus might have been called, On the Education of the Soul.
Despite his emphasis on Apollonian reason, Plato recognises that the original impulse for philosophy arises out of something as irrational and Dionysian as love. However, this love, although most fertile, is not of the reproductive kind, and must be reined in if it is to serve its purpose. For Plato, the body with its needs and pleasures is a source of distraction and confusion that hold us back from wisdom. In particular, the needs and desires of the body are why we waste our substance going to work and to war, focussing always on particulars rather than the universals that are the objects of wisdom.
Although Socrates and Phaedrus openly flirt with each other, Plato has them sit beneath a chaste tree. According to Pliny the Elder, the matrons of Athens, at the time of the Thesmophoria (the festival of Demeter and Persephone), used to place the stems and leaves of the chaste in their bedding to temper their lust.
When, at the end of the dialogue, Socrates prays to the gods of the place, he calls himself ‘a temperate man’; and when he asks Phaedrus to complete the prayer, Phaedrus responds, ‘Ask the same for me, for friends have all things in common.’ Thus, it is not as pederastic lovers but as friends and equals that they leave.
The genius of Plato is that the relationship between Socrates and Phaedrus is the very embodiment of the pure, ameliorating, elevating love of which they speak. And if this love begins as lust, this lust can be refined and sublimed on the ladder of love.
The ladder of love is the heart of Plato’s theory of love. To learn what it is, we must return to the Symposium and Agathon’s drinking party.
Diotima and the Ladder of Love
After Phaedrus, Pausanias, Eryximachus, Aristophanes, and the host, Agathon, it is the turn of Socrates to speak in praise of love (at this point, Alcibiades has not yet barged in). Socrates slips into his famous dialectic mode and gets Agathon to agree that if love is not of nothing, then it must be of something, and if it is of something, then it must be of something that is desired, and therefore of something that is lacking.
Socrates then relates a conversation that he once had with a mysterious priestess, Diotima of Mantinea, who, he says, taught him the art of love. This Diotima (the name means, ‘Honoured by the gods’)—who may have been a foil for Aspasia of Miletus—told him that the something that Love lacks and desires consists of beautiful and good things, and especially of wisdom, which is both extremely good and extremely beautiful.
If Love lacks and desires beautiful and good things, and if all the gods are good and beautiful, Love cannot, as most people think, be a god. In truth, Love is the child of Poverty and Resource, always in need but always inventive. He is not a god, but a great spirit (daimon) who intermediates between gods and men. As such, he is neither mortal nor immortal, neither wise nor ignorant, but a lover of wisdom (philosophos).
No one who is wise wants to become wise, just as no one who is ignorant wants to become wise: ‘For herein lies the evil of ignorance, that he who is neither good nor wise is nevertheless satisfied with himself…’ The aim of loving beautiful and good things is to possess them, because the possession of good and beautiful things is called happiness, and happiness is an end in itself.
Love is rather like the philosopher himself: neither a god nor a mortal, but a channel between the two; neither wise nor wholly ignorant, but aware of his lack and driven by it. For Plato, desire and philosophy are aspects of one and the same impulse, one and the same love: the love that seeks to know.
Love and Immortality
Wild animals, said Diotima, enter into a state of love because they seek to reproduce and make themselves immortal. People too seek to make themselves immortal, and are prepared to take great risks, even to die, to attain fame and honour. Some people are pregnant in body and beget children who will preserve their memory, but a few are pregnant in soul and instead beget wisdom and virtue. As their children are more beautiful and more immortal, people who are pregnant in soul have more to share with one another, and a stronger bond of friendship between them.
Who when he thinks of Homer and Hesiod and other great poets, would not rather have their children than ordinary human ones? Who would not emulate them in the creation of children such as theirs, which have preserved their memory and given them everlasting glory?
For Diotima as for Plato, love is something much larger than sexual or romantic attachment. It is the transcendent force that drives mortal beings to reach beyond their limited selves for the things they lack. It is the engine of art, philosophy, and, of course, of life itself.
The Ladder of Love
Diotima then told Socrates the proper way to learn to love beauty:
A youth should first be taught to love one beautiful body so that he comes to realize that this beautiful body shares beauty with every other beautiful body, and thus that it is foolish to love just one beautiful body. In loving all beautiful bodies, the youth begins to appreciate that the beauty of the soul is superior to the beauty of the body and begins to love those who are beautiful in soul, regardless of whether they are also beautiful in body.
Having thus transcended the physical, he gradually finds that beautiful practices and customs and the various kinds of knowledge also share in a common beauty.
Finally, on the highest rung of the ladder of love, he is able to experience Beauty itself, rather than its various apparitions. By exchanging the various apparitions of virtue for Virtue herself, he gains immortality and the love of the gods.
This is why love is so important, and why it deserves so much praise.
The beautiful youth is not the destination, but only the first rung of the ladder. He is only the apparition of beauty. But if we keep on climbing, we will arrive, first, at the Form of Beauty, and, finally, at the Form of the Good, which is the ultimate source of wisdom, virtue, and happiness. This close association of wisdom, virtue, and happiness is the seed of Aristotle’s virtue ethics.
How the Ladder of Love Changed Love
Before Plato, and for a long time after, people did, of course, fall in love, but they did not believe that this love might in some sense save them, as we tend to today. When, in the Iliad, Helen eloped with Paris, neither she nor he thought of their attraction as pure or noble or exalting. In the Odyssey, Penelope’s commitment to Odysseus is better understood in terms of dutiful love, or connubial fidelity, than modern, madcap romantic love. When, in the Aeneid, Dido falls in love with Aeneas, Virgil portrays her passion as a divine affliction that distracts both lovers from their duties and ends in ruin and death. Other models of love in antiquity include the ‘perfect friendship’ of Plato’s student Aristotle and the naturalism, or ‘beastliness’, of the Roman poets Lucretius and Ovid.
On the eastern edge of the Mediterranean, the Jewish and Christian models of love evolved alongside the Greco-Roman ones. In the Old Testament, God asks Abraham to sacrifice his precious son Isaac. But as Abraham is about to slay Isaac, an angel stays his hand. The Sacrifice of Isaac highlights that, although love and morality are important principles, unquestioning obedience to God is more important still, for God is morality, and God is love.
The New Testament, in contrast to the Old, elevates love for one another into the supreme virtue. More than a commandment, love becomes the royal road to redemption. One must even turn the other cheek to love one’s enemies. It is a far cry from the law of retaliation of the Old Testament: ‘…thou shalt give life for life, eye for eye, tooth for tooth…’
Even so, the Bible, which contains more named characters than Game of Thrones, contains not a single Bridget Jones story. Its greatest human love stories are between two women and two men: Ruth and Naomi, and David and Jonathan.
Jesus may have spoken Greek and might have come under the direct or indirect influence of Platonism. But even if he did not, the later Church sought to align Christian theology with classical philosophy—and Christian love, more properly called charity, and originally directed at God, began to blur with something much more individualistic.
The blending of Christian love with Platonism prepared the ground for the troubadour tradition that began in eleventh century Occitania (broadly, the southern half of France). A troubadour extolled refined or courtly love, which he directed at a married or otherwise unattainable lady, often of a superior rank, as a means of exalting himself and attaining to higher virtue. For the first time, love did not ultimately aim at, or depend on, God—and the Church duly condemned courtly love as a heresy. In a radical cultural reversal, the daughter of Eve turned from devilish temptress to sublime conduit of virtue, an earthly goddess in the place of God.
The troubadour tradition, which had remained an elite and minority movement, died out around the time of the Black Death in 1348, but prepared the ground for the modern conception of romantic love as the only thing left that might save us.
Continue Exploring
If you enjoyed this article, you might also look into For Better For Worse, an unconventional exploration of romantic love, marriage, and lasting relationships. For a broader exploration of love, desire, jealousy, and the emotions that shape our lives, see Heaven and Hell: The Psychology of the Emotions.
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