Early in his dialogue Phaedo, Plato has Socrates say to Simmias,
Do we say there is such a thing as the Just itself, or not?
Indeed we do, by Zeus (replies Simmias).
And the Beautiful and the Good?
Certainly.
And have you ever seen any such things with your eyes?
In no way, he said.
Have you grasped them with any other of the bodily senses? I mean concerning all those things, such as Size, Health, Strength, and everything else that each thing happens to be essentially.[1]
To anyone who has read the Socratic dialogues of Plato, this jump from talking of qualities to positing entities will seem like an unparalleled leap of faith. In a flash we go from speaking about just and beautiful and good things to speaking of Justice Itself, Beauty Itself, Goodness Itself, existing in another realm. These are not perceivable, as Socrates here insists, by the sense organs; they can be known only, he goes on to say, by pure reasoning (eilikrinei … dianoia).[2] So there is something in the world that transcends our senses, and some power of knowing that transcends sensation.
Simmias and Cebes, who are skeptical about the immortality of the soul, are easily convinced of the existence of Forms. Socrates subsequently develops a series of five arguments for immortality. The last, and most convincing of them, makes use of the Forms to support immortality. So in the end, the Theory of Forms saves the day, and persuades, or almost persuades, the doubters of immortality, just before Socrates loses his life by execution. Socrates, at least, is convinced of his immortality and looks forward to being freed from his mortal body with its distractions and limitations.
Expounding later in the Phaedo on the notion of Forms, Socrates says, “It seems to me that if anything is beautiful except the Beautiful Itself, it is so for no other reason than it partakes of that Beautiful.”[3] From this discussion it appears that the Form of Beauty is beautiful, and it is the cause or source of beauty for everything else in the world that we recognize as beautiful. The other things that have the property of beauty get it second-hand by participating or sharing in Beauty. This account is consistent with the story Socrates tells in the Symposium—the story he claims to have heard from Diotima—that we can arrive at a vision of Beauty by ascending from experiences with particular beautiful bodies to beautiful practices and sciences until we come to Beauty Itself.[4] He describes the encounter with Beauty as a kind of epiphany.
As Socrates continues in the Phaedo, he gives the example of Simmas, who is taller than Socrates but shorter that Phaedo. So Simmias is both tall and short in some sense. “It seems to me,” Socrates continues, “that not only Tallness Itself refuses to be both tall and short at the same time, but the tallness in us never accommodates the short nor allows itself to be exceeded, but one of two things happens: either it take flight and withdraws when its contrary, the short, approaches, or it perishes when it draws near.”[5] Here we have a particular property, the tallness in us, that occupies us or retreats according to the presence of a contrary property.
So when Simmas stands next to Socrates, tallness adheres to him; when he stands next to Phaedo, tallness retreats or disappears, while shortness adheres to him. What happens when he is standing between Socrates and Phaedo? This is an attempt, however awkward, to account for properties that belong to things.
The Theory of Forms, as it is called, appears first in Plato’s Phaedo and Symposium, and is amplified in later dialogues such as the Republic and Phaedrus. It is criticized in the Parmenides and perhaps modified in the Sophist. This theory is, as Aristotle, Plato’s student, informs us, a product of Plato’s thinking, not of Socrates’ inquiring.[6]
In the Republic, Plato has Socrates and Glaucon speak about Forms:
There are many beautiful things, I said, and many good things, and we say all of them exist and we distinguish them in speech.
We do.
And the Beautiful Itself and the Good Itself, and so on concerning the things we just referred to as many, insofar as each thing we consider stands for one Form (idea), as being one, we designate as ‘what is.’
Yes.
And we say the former are visible but not intelligible, the latter intelligible but not visible.
Of course.[7]
This principle is what Aristotle calls Plato’s One Over Many assumption. There are many beautiful things; they are all beautiful by participating in or sharing or imitating, or whatever, Beauty Itself. In general, the many Fs are F by connecting with Fness. Good things are good by participating in Goodness, wise people are wise by participating in Wisdom, and so on.
Plato holds that the Forms exist in a kind of world of their own, and are timeless, unlike us mortal human beings who are born and die and are constantly changing in many ways. In fact, it seems to be only in virtue of the connection between the timeless realm of the Forms and the constant flux of everyday life that we can have knowledge of the world around us. For there is order in the world of Forms that can find patterns in our crazy world of flux and change.
In many ways, these Form are ideal entities that we strive to exemplify in our lives and actions. There are, however, theoretical problems. For one thing, if the One Over Many assumption is perfectly general, it is also true that we are ugly by participating in Ugliness Itself, and bad by participating in Badness Itself.[8] Do we really want a world in which Ugliness and Badness are eternal realities? And when Socrates is ugly and Alcibiades is bad, are they just realizing their respective potentials?
Furthermore, what does it mean to say Beauty Itself is beautiful? What does Beauty itself in the abstract look like, sound like, feel like, taste like? It makes sense to call a statue, a human body, and orchid, or a symphony beautiful because these objects exist in time and space; but the world of Forms seems to exist outside time and space. And how does one distinguish the Form of Beauty from those of Justice and Goodness? Talk of beholding them only gets us so far.
[1] Plato Phaedo 65d-e.
[2] Plato Phaedo 66a.
[3] Plato Phaedo 100c.
[4] Plato Symposium 210a-212a.
[5] Plato Phaedo 102d-e.
[6] Aristotle Metaphysics I.6, 987b4-14.
[7] Plato Republic 6, 507b.
[8] Plato rarely focuses on undesirable Forms, but see, for instance, Republic 5, 475e-476a.