Excerpts from Plato

Here I gather together some key excerpts from Plato's writings, with some introduction and comment, which form the basis for the present critical reconstruction of Plato's Form theory and Socratic/Platonic reasoning.

Click here for a systematic explanation of key Platonic concepts involved in the excerpts commented on here.

#1. Separating the reality from the appearances of justice.
(Republic 358d-368c)

Habitual internal motives that are good for their own sake are the essence of what makes a person a good and admirable person.  Are there other possible motives motivating me to behave rightly or be good, that would also make me a more admirable person?  Basically, no.  Motives constitute moral goodness, so the quality of one's moral character is determined by one's ultimate motives.  Suppose Sara is motivated mainly by the desire to make money.  Last year this desire led her to take a purely competitive and uncaring attitude toward her fellow-workers, just trying to get promoted at others' expense.  This year her money-making motives have not changed one bit, but she now treats her fellow-workers kindly, but just as a means to impress a boss who values kindness.  Kind-Sara this year is really no better as a person than uncaring Sara last year.  As Plato puts it, this year she merely puts on the appearances or "seemings" (doxa) of kindness, but still does not have its essence.

To make this point about the difference between the concrete external "seemings" of goodness  and the invisible "essence" of goodness, Plato creates two extreme and unrealistic fictional examples in the passage below.  If a person gets lots of tangible social or monetary rewards for acting justly, we never know whether he is motivated to put on these seemings of justice by the desire for these rewards, or whether he is motivated purely by love of justice itself, valuing it for its own sake.  So one way of creating a concrete picture representing "the essence of justice" in its most pure form, is to imagine a story of a person who remains just even when he is getting no rewards for it at all, but is actually getting punished for his just behavior.  Plato probably has the example of Socrates in mind, condemned to death even though Plato says he was 'the most just man in Athens."  A later passage (quoted below) shows that Plato recognizes the unrealistic character of such a story.  It only serves as a kind of ideal model (paradeigma) for internal imitation, trying to purify one's motives of less admirable concerns.

Here is Plato's text:

Fathers, when they give advice to their sons... urge the necessity of being just, not by praising justice itself, but the good reputation with mankind that accrues from it. The object that they hold before us is that, by seeming to be just, the man may get from it reputation, office, connections, and all the good things... [And,] throwing in good standing with the gods, they have no lack of blessings to describe, which they affirm the gods give to pious men...
   

[But when it comes to deciding] between our two kinds of life [a just life and an unjust life], we shall be able to decide rightly [only] if we separate the most completely just and the most completely unjust man.

How, then, is this separation to be made?

Thus: We must subtract nothing of his injustice from [our image of] the unjust man or of his justice from [our image of] the just man, but assume the perfection of each in his own mode of conduct...

An Extreme Image of The Most Completely Unjust Man

The unjust man who attempts injustice rightly must be supposed to escape detection if he is to be altogether unjust, and we must regard the man who is caught as a bungler. For the height of injustice is to seem just [dokei dikaion einai] without being so [mē einai].

To the [image of the] perfectly unjust man, then, we must assign perfect injustice and withhold nothing of it, but we must allow him, while committing the greatest wrongs, to have secured for himself the greatest seeming of justice  [tēn megistēn doxan... eis dikaiosunen], and if he does happen to trip, we must concede to him the power to correct his mistakes by his ability to speak persuasively if any of his misdeeds come to light, and when force is needed, to employ force by reason of his manly spirit and vigor and his provision of friends and money.

An Extreme Image of the Most Completely Just Man

And when we have set up an unjust man of this character, our theory must set the [image of the] just man at his side - - a simple and noble man, who... does not wish to seem but to be good. Then we must deprive him of the seeming [to dokein]. Because if he seems [doxei] just, honors and gifts will come to him on account of this seeming [dokounti toiouto]. Then it will not be clear whether he is this way for the sake of justice or because of honors and gifts. He must be stripped bare of everything except justice... Doing no injustices, he must have the seeming [doxan echeto] of the greatest injustice, so that he may be put to the test as regards justice through not softening because of ill repute and the consequences thereof. But let him hold on his course unchangeable even unto death, seeming all his life to be unjust though being just,

so that [in these extreme images] both men attain... to the limit, the one of injustice, the other of justice...

Such being his disposition the just man will have to endure the lash, the rack, chains, the branding iron in his eyes, and finally, after every extremity of suffering, he will be crucified...
 

The Most Completely Unjust Man Desires the Seemings (doxa) of Justice, not the Being of Justice

The unjust man, as pursuing what clings closely to reality, to truth, and not regulating his life by opinion, desires not to seem but to be unjust. [He will get] first office and rule in the state because he has the seeming of justice, then a wife from any family he chooses, and the giving of his children in marriage to whomsoever he pleases. dealings and partnerships with whom he will, and in all these transactions advantage and profit for himself because he has no squeamishness about committing injustice. And so they say that if he enters into lawsuits, public or private, he wins and gets the better of his opponents, and, getting the better, is rich and benefits his friends and harms his enemies, and he performs sacrifices and dedicates votive offerings to the gods adequately and magnificently, and he serves and pays court to men whom he favors and to the gods far better than the just man, so that he may reasonably expect the favor of heaven also to fall rather to him than to the just.

A little further, Plato comments on this example:

#2. The Perfect "Divine" Other World

(Theaetetus 176a-c)

In the divine there is no shadow of unrighteousness, only the perfection of righteousness. And nothing is more like the divine than any one of us who becomes as righteous as possible. 176c

Evils can never be done away with [in this world]... they [do not] have any place in the divine world, but they must needs haunt this region of our mortal nature. That is why we should make all speed to take flight from this world to the other, and that means becoming like the divine so far as we can, and that again is to become righteous with the help of Wisdom. 176a

Although Plato does not explicitly mention the Forms in this passage, it is evident from other passages that the "divine" world he speaks of here is the world inhabited by the Forms.  Note that "taking flight from this world to the other" does not mean trying to actually live in this other divine world rather than the present earthly world.  It means taking perfect "divine" Platonic Forms as models for self-molding, trying to approximate these as closely as we can "becoming like the divine so far as we can."  So "taking flight from this world" means in practice "becoming as righteous as we can with the help of Wisdom" -- "Wisdom" for Plato consists in knowledge of the Forms.

#3. The Forms as "Divine Paradigms" for the Soul

(from the Republic)

At the center of Platonic thought is the quest for the right criteria a person should use for self-evaluation.  Plato thinks that only perfect virtue-concepts are suited to this purpose, because as he says "the imperfect is not the measure of anything."  (Winemakers do not take imperfect wines as a measure to try to live up to, but a sense of what a perfect wine would be.)

One peculiarity of Plato's language in the Republic is his use of the word "Being" to refer to the full perfection of Platonic-Forms.  What he means is that only the pure Platonic Form of Justice has the full being of the goodness of Justice.  Concrete just actions and just people are never perfect in their justice, but in Plato's words "participate in" this perfect Form. So they are said in a later passage to "roll around between being and not-being" -- i.e. it's wrong to say that they fully lack the Being of Justice, but also wrong to say that they fully have the Being of Justice.  This causes him sometimes to refer to the virtue-Forms themselves as simply "the Beings,"  and also describe them as "always Being" because they are pure and unchangeable in their goodness, unlike a virtuous person who is partly good and partly not good, and might change from being good today to being not good tomorrow.

This use of "Being" as interchangeable with "perfect" is illustrated in Republic 504c, where Plato says:

Here are some other passages illustrating this use of "Being" to refer to the Perfect Forms as perfect models to model oneself on.

Click here for a more detailed discussion of Key Passages from the Republic on the Forms

This is the chief passage in Plato illustrating the positive relation between concrete perceptions and the grasp of abstract Platonic Forms, using the example of Beauty.   Perceptions of individual concrete instances of beautiful things do not constitute knowledge of the perfect abstract Form of Beauty, but they are our only source of knowledge of perfect Beauty.  In Plato's image, the perfect Form of Beauty lies at the top of a mental ladder, but perceptions of concrete beautiful bodies serve as the indispensable "bottom rungs" on this ladder.  So in this passage, the one who wants to arrive at a grasp of the abstract Form of Beauty must begin by falling in love with one beautiful body.  The positive role of concrete perceptions in arriving at abstract Platonic Forms, illustrated in Plato's ladder-image, must be complemented by the negative picture implied in the image of the Cave (see #8 below).

Note that whereas the English word "beauty" has strong associations with visual beauty, the Greek word Plato uses is kalos, which has a broader meaning of "fine," or "refined."  This is why Plato can refer to "beautiful laws and institutions," and also regard "beauty" (to kalon) as a personal "virtue" (arete).

[To learn about beauty, one should] start when young by pursuing beautiful bodies. First... he will love one beautiful body... then he must realize that the beauty attached to one body is kin to [the beauty] attached to another body, so if it is necessary to pursue beauty in Form, it is great folly not to regard as one the beauty found in all bodies. Realizing this he must make himself a lover of all beautiful bodies...

After this he must realize that the beauty in souls is of much more value than the beauty in the body, [so that] if there is a soul with a little bloom [of beauty] beginning in it, he will love and care for it...

Contemplating [many specific] beautiful things rightly and in due order... he will suddenly have revealed to him something wonderful...

This [the Form of Beauty] is something always-being, not coming into being and perishing, not increasing and decreasing... It is not partly beautiful and partly shameful, nor now [beautiful] now-not [beautiful], nor in some respects beautiful and in some respects shameful... Nor will the beautiful appear to him as a face, or hands, nor any other part of the body... nor something existing in something else... but always being something single-formed having its own being with itself in itself... All other beautiful things participate in this, in such a manner that, while these other things come into being and perish, this thing becomes neither greater nor lesser...

Beginning from those beautiful things, always ascending upward for the sake of The Beautiful, like someone using the steps of a ladder, from one to two, and from two to all beautiful bodies, and from beautiful bodies to beautiful institutions, and from institutions to beautiful learnings, and from beautiful learnings... to that learning which is none other than the learning concerning The Beautiful...

What would you think if it happened to someone to see The Beautiful, exact, pure, unmixed... [What if] he were able to see unique Divine Beauty? Does it seem to you a trifling life for a man to lead, looking ‘over there,' contemplating it the way it should be [contemplated]?...

Seeing The Beautiful through what is visible, [he will] bring forth not images of virtue [arête], since he is in touch not with images [of virtue] but with true [virtue]... When he has brought forth and reared true virtue he is destined to become God-pleasing.

One statement... I can make in regard to all who have written... with a claim to knowledge of the subjects to which I devote myself... Such writers can in my opinion have no real acquaintance with the subject. I certainly have composed no work in regard to it nor shall I ever do so in future, for this subject matter [pragma] is by no means capable of spoken expression like other subjects... rather, after prolonged being-with and living-with the subject matter, suddenly, like a light kindled by a leaping spark, having come into being in the soul, it then nourishes itself. (341c-d)

Later he continues

... to learn as much as possible the truth about virtue and vice... it is necessary to pursue learning... with all effort and for a long time. By difficult comparing of each thing with other things, examining names and phrases (logoi), and sense-perceptions [aisthesis]... using every effort available in the capabilities of men, wisdom and understanding will light up. (344b)

#6. Platonic Forms as Inspiring and Soul-Satisfying

Platonic Forms are not only abstract general concepts. They are also inspiring because they are "transcendent" in their goodness. A personal grasp of a separated Platonic Form not only solves problems connected with contradictions uncovered by Socratic inquiry. In the ideal case it would also be uplifting and "soul satisfying." This makes sense of an otherwise puzzling passage in Republic Book 6:
 

Regarding "the right" and "the beautiful," many would prefer the seemings [ta dokounta] not the reality. Likewise with doing and possessing and seeming those things.  But regarding Goodness [ta agatha], possessing things that have the seemings [ta dokounta] satisfies no one, but they seek things that have the reality [ta onta]. Everyone here disregards seeming [doxa].  [What has the reality is] that which every soul seeks, and on account of this does everything, having a sense of what it is [ti einai], but puzzled and unable to adequately get what it is, or have a trustworthy belief about it as of other things, and because of this not able to obtain what is [truly] beneficial in other things.

Interpretation: Individuals like to impress others with their virtue, and in this case the reputation or external "seeming"  or "impressions" [doxa] of rightness and beauty serves as well or better than the actual possession of these virtues. (Earlier in the Republic Plato (see #1 above) speaks at length of those who prefer the seeming of rightness, and the difficulty of preferring the reality to the seeming.) But in this passage "the good" [agatha] stands for what is actually deeply satisfying to the possessor herself - a better English translation in this passage might be "what is meaningful," or "what makes life meaningful."  This makes for a plausible claim: That every individual ("every soul") does whatever she does in hopes of making her life a more meaningful life, and that no one is satisfied with merely appearing to have a meaningful life. Every individual does what she does in hopes that what she does in life will make her life more meaningful. But most people are confused and puzzled about this, and ultimately unsatisfied, because concrete-mindedness makes them attracted to the external and concrete "seeming" (doxa, ta dokounta) of meaningfulness, and they don't apprehend the Platonic Forms which contain its full reality (ta onta), the full reality of meaningfulness, which alone is really soul-satisfying.

#7. The Parable of the Cave
(From Plato’s Republic 514-519)

The ladder-image in the Symposium passage quoted in #4 above pictures the positive relation between concrete reality and the abstract Platonic Forms.  Concrete beautiful bodies serve as imperfect but easily accessible "bottom rungs" on Plato's ladder which serve as necessary starting points for understanding the much less easily accessible perfect Forms at the top of the ladder.

The parable of the Cave quoted below pictures the negative relation between concrete reality and the Forms.  Human concrete-mindedness makes people tend to mistake concrete visible actions and results of goodness for the invisible reality of goodness itself.  Plato compares this to an imagined situation in which prisoners are chained in a cave only able to face forward to a wall in front of them.  People behind a wall in back of the prisoners invisible to the prisoners carry statues of men and animals back and forth, casting shadows on the wall in front of them. The cave-dwellers, who have never seen the real world, mistakenly think that these shadows [the concrete appearances of goodness] are the real world [are true Goodness itself].  "These men are like us" says Plato. 

In Plato's parable, the individual who manages to climb out of the Cave represents the ideal Platonist philosopher.  This is the very purpose of philosophy in Plato's mind: to raise our minds beyond the imperfect concrete visible appearances of goodness (cave shadows) to grasp the abstract essence of perfect Goodness itself (the '"real world" outside the cave).

Plato has the parable end rather drastically: the individual who got free tries to return to the cave to free his companions. But they are so attached to the world of the cave shadows, and so threatened by the idea that this is not the real world, that they want to kill him.  Again it seems likely that this parable is Plato's way of representing the life and death of his ideal philosopher, Socrates.

Imagine men living in an underground cave-like dwelling place, which has a way up to the light along its whole width, but the entrance is a long way up. The men have been there from childhood, with their neck and legs in fetters, so that they remain in the same place and can only see ahead of them, as their bonds prevent them turning their heads. Light is provided by a fire burning some way behind and above them. Between the fire and the prisoners, some way behind them and on a higher ground, there is a path across the cave and along this a low wall has been built, like the screen at a puppet show in front of the performers who show their puppets above it.

See then also men carrying along that wall, visible over its top, all kinds of artifacts, statues of men, reproductions of other animals in stone or wood fashioned in all sorts of ways.

[These men] are like us.

Such men could not see anything of themselves and each other except the shadows which the fire casts upon the wall of the cave in front of them? And is not the same true of the objects carried along the wall?  If they could converse with one another, do you not think that they would consider these shadows to be the real things? Such men would believe the truth to be nothing else than the shadows of the artifacts.
 

Getting Free, Seeing "the Real World"

Consider then what deliverance from their bonds and the curing of their ignorance it would be if something like this naturally happened to them:

Whenever one of them was freed, had to stand up suddenly, turn his head, walk, and look up toward the light, doing all that would give him pain, the flash of the fire would make it impossible for him to see the objects of which he had earlier seen the shadows. What do you think he would say if he was told that what he saw before was foolishness, that he was now somewhat closer to reality and turned to things that existed more fully, that he saw more correctly? If one then pointed to each of the objects passing by, asked him what each was, and forced him to answer, do you not think he would be at a loss and believe that the things which he saw earlier were truer than the things now pointed out to him?

If one then compelled him to look at the fire itself, his eyes would hurt, he would turn round and flee toward those things which he could see, and think that they were in fact clearer than those now shown to him.

And if one were to drag him thence by force up the rough and steep path, and did not let him go before he was dragged into the sunlight, would he not be in physical pain and angry as he was dragged along?

When he came into the light, with the sunlight filling his eyes, he would not be able to see a single one of the things which are now said to be true.

I think he would need time to get adjusted before he could see things in the world above; at first he would see shadows most easily, then reflections of men and other things in water, then the things themselves. After this he would see objects in the sky and the sky itself more easily at night, the light of the stars and the moon more easily than the sun and the light of the sun during the day.

Then, at last, he would be able to see the sun, not images of it in water or in some alien place, but the sun itself in its own place, and be able to contemplate it.

After this he would reflect that it is the sun which provides the seasons and the years, which governs everything in the visible world, and is also in some way the basis of those other things which he used to see.
 

Returning to the Cave

What then? As he reminds himself of his first dwelling place, of the wisdom there and of his fellow prisoners, would he not reckon himself happy for the change, and pity them?

And if the men below had praise and honors from each other, and prizes for the man who saw most clearly the shadows that passed before them, and who could best remember which usually came earlier and which later, and which came together and thus could most ably prophesy the future, do you think our man would desire those rewards and envy those who were honored and held power among the prisoners, or would he feel, as Homer put it, that he certainly wished to be "serf to another man without possessions upon the earth" and go through any suffering, rather than share their opinions and live as they do?
    If this man went down into the cave again and sat down in the same seat, would his eyes not be filled with darkness, coming suddenly out of the sunlight?

And if he had to contend again with those who had remained prisoners in recognizing those shadows while his sight was affected and his eyes had not settled down - and the time for this adjustment would not be short - would he not be ridiculed? Would it not be said that he had returned from his upward journey with his eyesight spoiled, and that it was not worthwhile even to attempt to travel upward?

As for the man who tried to free them and lead them upward, if they could somehow lay their hands on him and kill him, they would do so.

Interpreting the Story

This whole image... must be related to what we said before [about the perfect Forms of Goodness]. The realm of the visible should be compared to the prison dwelling, and the fire inside it to the power of the sun. If you interpret the upward journey and the contemplation of things above as the upward journey of the soul to the realm of Understanding, [ton noeton topon] you will grasp what I’m suggesting.

In the realm of pure Understanding, the Form of the Good is the last to be seen [horasthai], and with difficulty. When seen it must be reckoned to be for all the basis [aitia] of all that is right [orthos] and beautiful, to have produced in the visible world both light and the fount of light, while in the realm of Understanding it is itself mistress of truth and understanding [nous], and he who is to act intelligently in public or in private must see it.

Do not be surprised that those who have reached this point are unwilling to occupy themselves with human affairs, and that their souls are always pressing upward to spend their time there, for this is natural if things are as our parable indicates.
    Is it at all surprising that anyone coming to the evils of human life from the contemplation of the divine behaves awkwardly and appears very ridiculous while his eyes are still dazzled and before he is sufficiently adjusted to the darkness around him, if he is compelled to contend in court or some other place about the shadows of justice or the objects of which they are shadows, and to carry through the contest about these in the way these things are understood by those who have never seen Justice itself?

Anyone with intelligence would remember that the eyes may be confused in two ways and from two causes, coming from light into darkness as well as from darkness into light. Realizing that the same applies to the soul, whenever he sees a soul disturbed and unable to see something, he will not laugh mindlessly but will consider whether it has come from a brighter life and is dimmed because unadjusted, or has come from greater ignorance into greater light and is filled with a brighter dazzlement. The former he would declare happy in its life and experience, the latter he would pity, and if he should wish to laugh at it, his laughter would be less ridiculous than if he laughed at a soul that has come from the light above.

If these things are true, [then] education is not what some declare it to be; they say that knowledge is not present in the soul, and that they put it in, like putting sight into blind eyes

Our present argument shows that the capacity to learn and the organ with which to do so are present in every person's soul. It is as if it were not possible to turn the eye from darkness to light without turning the whole body; so one must turn one's whole soul from the world of becoming [gignomenon] until it can endure to contemplate reality and the brightest of realities [to on kai tou ontos tou phanotaton], which we say is the Good.

Education then is the art of doing this very thing, this turning around, the knowledge of how the soul can most easily and most effectively be turned around; it is not the art of putting the capacity of sight into the soul; the soul possesses that already but it is not turned the right way or looking where it should. This is what education has to deal with.

The virtue of Understanding [phronesis] belongs above all to something more divine [theios], which never loses its capacity but, according to which way it is turned, becomes useful and beneficial or useless and harmful.
Have you never noticed in men who are said to be wicked but clever, how sharply their little soul looks into things to which it turns its attention? Its capacity for sight is not inferior, but it is compelled to serve evil ends, so that the more sharply it looks the more evils it works.

Yet if a soul of this kind had been hammered at from childhood and those excrescences had been knocked off it which belong to the world of becoming and have been fastened upon it by feasting, gluttony, and similar pleasures, and which like leaden weights draw the soul to look downward – if, being rid of these, it turned to look at things that are true, then the same soul of the same man would see these just as sharply as it now sees the things towards which it is directed.

#8. Key Republic Passages on the Forms.

The next passage quoted below presents Plato's central ideas regarding the Forms.  It is very helpful in gaining a contextual understanding of many key terms in Plato's philosophical vocabulary, such as "Always the same," "Essence," "Being," "Appearances," "Sense-perception," "Mental Understanding" and so on (a contextual understanding of these terms is presented in another essay.)

This passage itself is somewhat difficult -- I've given a fuller explanation in a separate essay for those interested.  Here I will introduce this passage with some shorter comments summarizing the main points:

The central problem for Plato is formulating ideal virtue-concepts that will invariably make a person a more and more admirable person as she comes closer to realizing these ideals.  Problems arise because of the common tendency to conceptualize virtue in terms of concrete, easy-to-understand visualizable images. Using such concrete images as a guide will sometimes lead to genuinely admirable actions, and sometimes lead to actions that are clearly not admirable. This is in contrast to the Forms which are unchanging in their ability to represent something good and admirable.
    "Concrete image" is my way of describing something Plato refers to in various other ways in the passage quoted below:
    - These are images of conduct that can be perceived by the physical senses (aisthesis), primarily the sense of sight. These are images of conduct that can be visualized. The Forms, by contrast, cannot be visualized, and so grasping them requires developing a mental capacity (noesis) able to think in concepts separated from anything concretely visualizable.
    - These concrete images are the external appearances, the "seeming" (doxa) of true virtue. It is incorrect to say that they represent nothing of the "being" of true virtue, but they do not represent the full being of virtue either. For the person able to grasp the Form containing the full being of a particular virtue (what it is that makes this virtue admirable), these external appearances will appear to lie between not-being-admirable-virtue and fully-being-admirable-virtue. Grasping the full "Being" of a virtue again requires kind of knowing opposite knowing-appearances (doxazein), which Plato calls in this context episteme, or gnosis (the equivalent of noesis).
    - No single concrete image will represent every instance of a particular virtue (e.g. there are many other "right actions" besides the action of giving back a person what belongs to him). So the person who thinks only in terms of concrete images will tend to conceive each virtue under multiple forms, and so will lack the unified and concentrated focus for moral commitment which Forms provide for the ideal Platonist. This is the main point of Plato’s contrast between "the one and the many" in this passage (e.g. "many right actions" and "one Form" of Rightness.)

Shortly before the passage quoted here, Plato contrasts his true philosopher with young men in Greece who travel around to all the Dionysiac festivals.  They love the "beautiful sights" at the theater-plays and parties that accompany these festivals, i.e. sense-perceptions (aisthesis) of the external "appearances" or "impressions" about beauty, here called doxa, in contrast to true Platonic "Knowledge" of Beauty Itself, here called episteme or gnosis.  This context of theater and party-going is important for a proper understanding of the word doxa, often mistakenly translated as "opinion" (as though the contrast is between different theories about Beauty, some theories constituting uncertain, subjective "opinion," whereas other theories constitute thoroughly reliable, rationally established, objective "Knowledge.")

Here is Plato's passage:

Since "the beautiful" is the opposite of "the shameful," they are two... Since they are two [concepts], each is one [concept]. And in respect to "the right" and "the not-right," "the good" and "the bad," and all the Forms... each is one, but because of mingling with bodies and actions and each other, each appears everywhere under many appearances.
I make a distinction like this: I set apart... the sight-lovers [philo-theamones] and lovers of skill and action, and separate them from those whom our talk concerns, who alone are rightly called lovers of wisdom [philo-sophous].
    The lovers of sound and sights delight in beautiful tones and colors and shapes, and everything that artful skill creates out of these, but their thought is unable to see and take delight in the nature of the Beautiful Itself. [Those are] few who are able to approach Beauty Itself, and see it by itself.
    [So we have one kind of person] who attends to beautiful actions, but does not attend to the Beautiful Itself, nor is able to follow when someone tries to guide him to the knowledge of it.
    [And then there is the person who is] the opposite of these: someone who recognizes the Beautiful Itself, and is able to see both it and what participates in it, and does not mistake what participates in it for it itself, nor mistake it itself for what participates in it...

479a
    [Suppose there is] a person who does not think there is the Beautiful Itself, or any Idea of Beauty Itself always remaining the same, but who attends to many beautiful things - - the sight-lover, I mean, who cannot endure to hear anybody say that the beautiful is one and the just one, and so of other things.
    Is there any one of these many beautiful things that will not appear shameful? And of the right things, that will not seem not- right? And of the holy things, that will not seem unholy?
    And again, do the many double things appear any the less halves than doubles? And likewise of the long and the short things, the light and the heavy things - - can these things be said of them [any more than] the opposite?...

    So in regard to each of these many things: "Is" it more than it "is- not" whatever one might say it is?
    It is like those who pun on double meanings at banquets, or the children's riddle about the eunuch and his hitting the bat - - what they say he hit it with and as it sat on what. [See footnote [1] for an explanation of this riddle.]
    These things too are double-meaninged, and it is impossible to conceive firmly any one of them to "be" or "not-be," or both, or neither.
    [There is not] a better place to put them than that midway between being [ousia] and not being [me einai]. For we shall surely not discover a darker region than not-being [me on], that something should "not be" still more, nor a brighter region than being [on], that something should "be" still more.
    We would seem to have found, then, that the many conventions of the many people about the beautiful and other things are tumbled about in the mid-region between what "is-not" and what exactly "is."
    Anything of this kind...  must be called "what one has impressions about" [doxaston] not what is Known [gnoston], the wanderer between being caught by this in-between [mental] capacity [i.e. doxa].
    Those who see many beautiful things, but do not see The Beautiful... and see many right things but not The Right, and everything like this - - we should say they "have impressions" [doxazein] about everything, but do not Know what they have impressions about.
    What about those who see each of those things, the things that always are the same? [We should] say they "Know," not that they "have impressions" [doxazein"].
    [We should] say that those who take delight in and love those things about which there is Knowledge, the others [take delight in and love those things] about which there are "impressions" [doxa]... These love and give their attention to beautiful sounds and colors and similar things, but cannot bear the Beautiful as something that "is". [We should] call them "lovers of impressions" [philo-doxous] rather than "lovers of wisdom" [philo-sophous]...
    Those who delight in the "being" of each thing [hekaston to on] should be called "lovers of wisdom" [philo-sophous] not "lovers of impressions" [philo-doxous].

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The above passage is also important for showing how invisible Platonic Forms are derived by abstraction from perceptions of concrete visible behavior, and also how this mental abstraction serves to solve problems raised by Socratic questioning.  Understanding this point requires connecting this passage to a later passage in Republic Book 7.  What follows explains this connection.

Begin with what Plato says in one part of the above passage:

Is there any one of these many beautiful things that will not appear shameful? And of the right things, that will not seem not-right? And of the holy things, that will not seem unholy?  And again, do the many double things appear any the less halves than doubles? And likewise of the long and the short things, the light and the heavy things - - can these things be said of them [any more than] the opposite?... So in regard to each of these many things: "Is" it more than it "is-not" whatever one might say it is?

These comments associate the contrast between "right" and "not-right" with the contrast between "long" and "short." this association connects this passage to the passage in Book 7 of the Republic which speaks more at length about "long" and "short" as abstract concepts.  In this latter passage in Book 7, Plato asks us to consider a person looking at three fingers on a hand, the little finger, the ring finger, and the middle finger. Is the ring finger short or long? Answer: It is short in relation to the middle finger, but long in relation to the little finger.

Plato analyzes this observation about the short-and-long finger in a very odd way. He imagines the sense of sight reporting to the mind contradictory things about the same single finger. It reports the single finger to be both long and short, confusing the mind. The sense of sight itself is unable to resolve this contradiction, but there is another mental capacity noesis, mental understanding, which is able to resolve the contradiction. Noesis can do this because it has the ability to understand concepts which are not tied to any concrete material objects. 

As Plato pictures it the mind is confused because the sense of sight sees "finger," "long," and "short" all mixed together as though they were one thing. Only noesis, as purely mental understanding, is able to resolve this contradiction, because, unlike sight, it is able to mentally "separate" (abstract) the two contradictory concepts "long" and "short" from each other and from the concrete finger.

In Plato's words

[In the case of the ring finger] the sense of sight sees "long" and "short," but not as separate, but as mixed together [in one finger]. So in order to clarify this, mental understanding [noesis] is compelled to see "long" and "short" not as mixed together but as separate, the opposite way from sight.

And it is from some such circumstances that it first occurs to us to ask, "What is ‘the long', and again of ‘the short'?'' And so we call these [latter] things "mentally understood" (noeton) and the other things "visibly seen" (horaton.)

Some among our sensory perceptions [aisthesis] do not call upon noēsis to examine them... Others certainly summon the help of noēsis to examine them because aisthesis/sense-perception produces nothing sound. They do not call for help...if they do not at the same time signal contradictory perceptions [enantian aisthesis]; I describe those that do as calling for help whenever the sense perception does not point to one thing rather than its opposite.

In these cases we need to call upon... noesis, to examine whether each of the things announced to it is one or two...

These comments about long and short fingers are very odd and implausible in themselves. (Who is ever actually puzzled by this supposed problem?) They are important because of the way they connect to the contradictions uncovered in Socratic questioning, and what they suggest about Platonic Forms as a way of resolving these contradictions.  Socratic questioning shows that the human habit of representing virtue by means of concrete visible images does generate contradictions which are a frequent source of moral confusion. For example, if I try to represent "rightness" by means of the visible image of one person returning property to its owner, then Plato's story of the weapons-owner gone insane will be a source of some confusion. Here it is plausible to say that I will see the same action "giving to each what is his" as being both right (on some occasions) and not-right (on other occasions). 

As he said in an earlier passage in the Republic (331c), attempting to define "rightness" as "giving to each what belongs to him," would mean that doing "the same things" (auta tauta) would amount to "sometimes acting rightly and sometimes not rightly" (auta tauta estin eniote men dikaiōs, eniote adikōs poein).

In a different passage in Book 5, Plato himself connects the observations about the long/short contradiction in the case of fingers, and the right/not-right contradiction in the case of the weapons-owner gone insane described in Republic Book 1.

He says in one passage (479b)

What about the many things that are "double"? Are they any less "half" than "double"? So with things "long" and "short", - - can these things be said of them [any more than] the opposite?...

No... Each of these things partakes of both opposites.

In the immediately preceding passage (479a) he uses the same ideas to describe contradictions that arise in relation to virtue-concepts:

Is there any one of the many "beautiful" things that will not appear "shameful"? or any one of the many "right" things that will not [appear] "not-right"? Or any one of the many "holy" [things that will] not [appear] "unholy"...

Here also Plato uses the same imagery of contradictory forms somehow getting "mixed together" in single concrete things or images:

Since "the beautiful" is the opposite of "the shameful," they are two... Since they are two [concepts], each is one [concept]. And in respect to "the right" and "the not-right," "the good" and "the bad," and all the Forms... each is one, but because of mingling with bodies and actions and each other, each appears everywhere under many appearances.

The Form of Beauty, mentally understood (by noesis) as something separate from concrete bodies and concrete actions, is something single containing no contradictions within itself, pure Beauty. But when we perceive beautiful bodies and beautiful actions, we are not perceiving this single Form as single and pure, but as mingled with other Forms, sometimes with opposite Forms. (The plays that theater-goers see show things partly beautiful and partly not-beautiful.)  This "mixing" with other Forms in concrete visible behavior is what makes the single invisible Form "Beauty" present itself to us under many diverse visible appearances.

Our habitual concrete-mindedness, letting our thought be determined by concrete images of visible reality, always presents reality to us in "gray areas," a mixture of the good and not-good, in which things are constantly changing from being good and admirable to being not good and not admirable.   A person seeking pure goodness in this mixed concrete reality will always be confused, just as Plato pictures the mind confused by the fact that a single visible finger appears to exemplify two contradictory concepts, "long" and "short."  The confusion about the finger can only be resolved by treating "long" and "short" as abstract concepts, separated from each other and from the visible finger.  In the same way, the confusion caused by trying to define "rightness" in terms of concrete behavior can only be resolved by mentally separating the abstract concept of "rightness'" from any image or rule depicting concrete visible "right" behavior.

At the same time, this passage also illustrates the fact that sense-perceptions of concrete visible reality are the ultimate source of our knowledge of abstract Platonic Forms.  We do not learn the concepts "long" and "short" by direct intuition of the concepts themselves, but by abstracting these concepts from our perceptions of concrete, visible, long and short objects.  In the same way, we cannot directly intuit the Platonic Form of rightness, but must derive this from our perception of concrete visible behavior we perceive to be right and not right.