According to scholarly readers of Plato, the center part of any dialogue contains the most important claims. This is certainly true for Plato's most famous work, The Republic.
Turning to the end of Book V, Plato makes one of the most important claims of the Republic: only the philosopher has knowledge. This section is also important as it amounts to a defense of the activity of philosophy, and explains why philosophy is crucial to the life of the city, rather than a threat to society.
In the section posted below, we find echoes of earlier pre-Socratic philosophers, especially Parmenides' division between "what is" and "what is not", as it relates to the principled distinction between knowledge, ignorance and opinion. We will also want to square this section with Socrates' famous disclaimer that he knows nothing.
Let's read together:
Let me begin by reminding you that we found our way hither in the search after justice and injustice.
True, he replied; but what of that?
I was only going to ask whether, if we have discovered them, we are to require that the just man should in nothing fail of absolute justice; or may we be satisfied with an approximation, and the attainment in him of a higher degree of justice than is to be found in other men?
The approximation will be enough.
We were enquiring into the nature of absolute justice and into the character of the perfectly just, and into injustice and the perfectly unjust, that we might have an ideal. We were to look at these in order that we might judge of our own happiness and unhappiness according to the standard which they exhibited and the degree in which we resembled them, but not with any view of showing that they could exist in fact.
True, he said.
Would a painter be any the worse because, after having delineated with consummate art an ideal of a perfectly beautiful man, he was unable to show that any such man could ever have existed?
He would be none the worse.
Well, and were we not creating an ideal of a perfect State?
To be sure.
And is our theory a worse theory because we are unable to prove the possibility of a city being ordered in the manner described?
Surely not, he replied.
That is the truth, I said. But if, at your request, I am to try and show how and under what conditions the possibility is highest, I must ask you, having this in view, to repeat your former admissions.
I want to know whether ideals are ever fully realized in language? Does not the word express more than the fact, and must not the actual, whatever a man may think, always, in the nature of things, fall short of the truth? What do you say?
Then you must not insist on my proving that the actual State will in every respect coincide with the ideal: if we are only able to discover how a city may be governed nearly as we proposed, you will admit that we have discovered the possibility which you demand; and will be contented. I am sure that I should be contented—will not you?
Yes, I will.
Let me next endeavour to show what is that fault in States which is the cause of their present maladministration, and what is the least change which will enable a State to pass into the truer form; and let the change, if possible, be of one thing only, or, if not, of two; at any rate, let the changes be as few and slight as possible.
Certainly, he replied.
I think, I said, that there might be a reform of the State if only one change were made, which is not a slight or easy though still a possible one.
What is it? he said.
Now then, I said, I go to meet that which I liken to the greatest of the waves; yet shall the word be spoken, even though the wave break and drown me in laughter and dishonour; and do you mark my words.
I said: 'Until philosophers are kings, or the kings and princes of this world have the spirit and power of philosophy, and political greatness and wisdom meet in one, and those commoner natures who pursue either to the exclusion of the other are compelled to stand aside, cities will never have rest from their evils,—nor the human race, as I believe,—and then only will this our State have a possibility of life and behold the light of day.' Such was the thought, my dear Glaucon, which I would fain have uttered if it had not seemed too extravagant; for to be convinced that in no other State can there be happiness private or public is indeed a hard thing.
Socrates, what do you mean? I would have you consider that the word which you have uttered is one at which numerous persons, and very respectable persons too, in a figure pulling off their coats all in a moment, and seizing any weapon that comes to hand, will run at you might and main, before you know where you are, intending to do heaven knows what; and if you don't prepare an answer, and put yourself in motion, you will be 'pared by their fine wits,' and no mistake.
You got me into the scrape, I said.
And I was quite right; however, I will do all I can to get you out of it; but I can only give you good-will and good advice, and, perhaps, I may be able to fit answers to your questions better than another—that is all. And now, having such an auxiliary, you must do your best to show the unbelievers that you are right.
I ought to try, I said, since you offer me such invaluable assistance. And I think that, if there is to be a chance of our escaping, we must explain to them whom we mean when we say that philosophers are to rule in the State; then we shall be able to defend ourselves: There will be discovered to be some natures who ought to study philosophy and to be leaders in the State; and others who are not born to be philosophers, and are meant to be followers rather than leaders.
Then now for a definition, he said.
Follow me, I said, and I hope that I may in some way or other be able to give you a satisfactory explanation.
I dare say that you remember, and therefore I need not remind you, that a lover, if he is worthy of the name, ought to show his love, not to some one part of that which he loves, but to the whole.
I really do not understand, and therefore beg of you to assist my memory.
Another person, I said, might fairly reply as you do; but a man of pleasure like yourself ought to know that all who are in the flower of youth do somehow or other raise a pang or emotion in a lover's breast, and are thought by him to be worthy of his affectionate regards. Is not this a way which you have with the fair: one has a snub nose, and you praise his charming face; the hook-nose of another has, you say, a royal look; while he who is neither snub nor hooked has the grace of regularity: the dark visage is manly, the fair are children of the gods; and as to the sweet 'honey pale,' as they are called, what is the very name but the invention of a lover who talks in diminutives, and is not averse to paleness if appearing on the cheek of youth? In a word, there is no excuse which you will not make, and nothing which you will not say, in order not to lose a single flower that blooms in the spring-time of youth.
If you make me an authority in matters of love, for the sake of the argument, I assent.
And what do you say of lovers of wine? Do you not see them doing the same? They are glad of any pretext of drinking any wine.
And the same is true of ambitious men; if they cannot command an army, they are willing to command a file; and if they cannot be honoured by really great and important persons, they are glad to be honoured by lesser and meaner people,—but honour of some kind they must have.
Once more let me ask: Does he who desires any class of goods, desire the whole class or a part only?
And may we not say of the philosopher that he is a lover, not of a part of wisdom only, but of the whole?
Yes, of the whole.
And he who dislikes learning, especially in youth, when he has no power of judging what is good and what is not, such an one we maintain not to be a philosopher or a lover of knowledge, just as he who refuses his food is not hungry, and may be said to have a bad appetite and not a good one?
Very true, he said.
Whereas he who has a taste for every sort of knowledge and who is curious to learn and is never satisfied, may be justly termed a philosopher? Am I not right?
Glaucon said: If curiosity makes a philosopher, you will find many a strange being will have a title to the name. All the lovers of sights have a delight in learning, and must therefore be included. Musical amateurs, too, are a folk strangely out of place among philosophers, for they are the last persons in the world who would come to anything like a philosophical discussion, if they could help, while they run about at the Dionysiac festivals as if they had let out their ears to hear every chorus; whether the performance is in town or country—that makes no difference—they are there. Now are we to maintain that all these and any who have similar tastes, as well as the professors of quite minor arts, are philosophers?
Certainly not, I replied; they are only an imitation.
He said: Who then are the true philosophers?
Those, I said, who are lovers of the vision of truth.
That is also good, he said; but I should like to know what you mean?
To another, I replied, I might have a difficulty in explaining; but I am sure that you will admit a proposition which I am about to make.
What is the proposition?
That since beauty is the opposite of ugliness, they are two?
And inasmuch as they are two, each of them is one?
And of just and unjust, good and evil, and of every other class, the same remark holds: taken singly, each of them is one; but from the various combinations of them with actions and things and with one another, they are seen in all sorts of lights and appear many?
And this is the distinction which I draw between the sight-loving, art-loving, practical class and those of whom I am speaking, and who are alone worthy of the name of philosophers.
How do you distinguish them? he said.
The lovers of sounds and sights, I replied, are, as I conceive, fond of fine tones and colours and forms and all the artificial products that are made out of them, but their mind is incapable of seeing or loving absolute beauty.
True, he replied.
Few are they who are able to attain to the sight of this.
And he who, having a sense of beautiful things has no sense of absolute beauty, or who, if another lead him to a knowledge of that beauty is unable to follow—of such an one I ask, Is he awake or in a dream only? Reflect: is not the dreamer, sleeping or waking, one who likens dissimilar things, who puts the copy in the place of the real object?
I should certainly say that such an one was dreaming.
But take the case of the other, who recognises the existence of absolute beauty and is able to distinguish the idea from the objects which participate in the idea, neither putting the objects in the place of the idea nor the idea in the place of the objects—is he a dreamer, or is he awake?
He is wide awake.
And may we not say that the mind of the one who knows has knowledge, and that the mind of the other, who opines only, has opinion?
But suppose that the latter should quarrel with us and dispute our statement, can we administer any soothing cordial or advice to him, without revealing to him that there is sad disorder in his wits?
We must certainly offer him some good advice, he replied.
Come, then, and let us think of something to say to him. Shall we begin by assuring him that he is welcome to any knowledge which he may have, and that we are rejoiced at his having it? But we should like to ask him a question: Does he who has knowledge know something or nothing? (You must answer for him.)
I answer that he knows something.
Something that is or is not?
Something that is; for how can that which is not ever be known?
And are we assured, after looking at the matter from many points of view, that absolute being is or may be absolutely known, but that the utterly non-existent is utterly unknown?
Nothing can be more certain.
Good. But if there be anything which is of such a nature as to be and not to be, that will have a place intermediate between pure being and the absolute negation of being?
Yes, between them.
And, as knowledge corresponded to being and ignorance of necessity to not-being, for that intermediate between being and not-being there has to be discovered a corresponding intermediate between ignorance and knowledge, if there be such?
Do we admit the existence of opinion?
As being the same with knowledge, or another faculty?
Then opinion and knowledge have to do with different kinds of matter corresponding to this difference of faculties?
And knowledge is relative to being and knows being. But before I proceed further I will make a division.
I will begin by placing faculties in a class by themselves: they are powers in us, and in all other things, by which we do as we do. Sight and hearing, for example, I should call faculties. Have I clearly explained the class which I mean?
Yes, I quite understand.
Then let me tell you my view about them. I do not see them, and therefore the distinctions of figure, colour, and the like, which enable me to discern the differences of some things, do not apply to them. In speaking of a faculty I think only of its sphere and its result; and that which has the same sphere and the same result I call the same faculty, but that which has another sphere and another result I call different. Would that be your way of speaking?
And will you be so very good as to answer one more question? Would you say that knowledge is a faculty, or in what class would you place it?
Certainly knowledge is a faculty, and the mightiest of all faculties.
And is opinion also a faculty?
Certainly, he said; for opinion is that with which we are able to form an opinion.
And yet you were acknowledging a little while ago that knowledge is not the same as opinion?
Why, yes, he said: how can any reasonable being ever identify that which is infallible with that which errs?
An excellent answer, proving, I said, that we are quite conscious of a distinction between them.
Then knowledge and opinion having distinct powers have also distinct spheres or subject-matters?
That is certain.
Being is the sphere or subject-matter of knowledge, and knowledge is to know the nature of being?
And opinion is to have an opinion?
And do we know what we opine? or is the subject-matter of opinion the same as the subject-matter of knowledge?
Nay, he replied, that has been already disproven; if difference in faculty implies difference in the sphere or subject-matter, and if, as we were saying, opinion and knowledge are distinct faculties, then the sphere of knowledge and of opinion cannot be the same.
Then if being is the subject-matter of knowledge, something else must be the subject-matter of opinion?
Yes, something else.
Well then, is not-being the subject-matter of opinion? or, rather, how can there be an opinion at all about not-being? Reflect: when a man has an opinion, has he not an opinion about something? Can he have an opinion which is an opinion about nothing?
He who has an opinion has an opinion about some one thing?
And not-being is not one thing but, properly speaking, nothing?
Of not-being, ignorance was assumed to be the necessary correlative; of being, knowledge?
True, he said.
Then opinion is not concerned either with being or with not-being?
Not with either.
And can therefore neither be ignorance nor knowledge?
That seems to be true.
But is opinion to be sought without and beyond either of them, in a greater clearness than knowledge, or in a greater darkness than ignorance?
Then I suppose that opinion appears to you to be darker than knowledge, but lighter than ignorance?
Both; and in no small degree.
And also to be within and between them?
Then you would infer that opinion is intermediate?
But were we not saying before, that if anything appeared to be of a sort which is and is not at the same time, that sort of thing would appear also to lie in the interval between pure being and absolute not-being; and that the corresponding faculty is neither knowledge nor ignorance, but will be found in the interval between them?
And in that interval there has now been discovered something which we call opinion?
Then what remains to be discovered is the object which partakes equally of the nature of being and not-being, and cannot rightly be termed either, pure and simple; this unknown term, when discovered, we may truly call the subject of opinion, and assign each to their proper faculty,—the extremes to the faculties of the extremes and the mean to the faculty of the mean.
This being premised, I would ask the gentleman who is of opinion that there is no absolute or unchangeable idea of beauty—in whose opinion the beautiful is the manifold—he, I say, your lover of beautiful sights, who cannot bear to be told that the beautiful is one, and the just is one, or that anything is one—to him I would appeal, saying, Will you be so very kind, sir, as to tell us whether, of all these beautiful things, there is one which will not be found ugly; or of the just, which will not be found unjust; or of the holy, which will not also be unholy?
No, he replied; the beautiful will in some point of view be found ugly; and the same is true of the rest.
And may not the many which are doubles be also halves?—doubles, that is, of one thing, and halves of another?
And things great and small, heavy and light, as they are termed, will not be denoted by these any more than by the opposite names?
True; both these and the opposite names will always attach to all of them.
And can any one of those many things which are called by particular names be said to be this rather than not to be this?
He replied: They are like the punning riddles which are asked at feasts or the children's puzzle about the eunuch aiming at the bat, with what he hit him, as they say in the puzzle, and upon what the bat was sitting. The individual objects of which I am speaking are also a riddle, and have a double sense: nor can you fix them in your mind, either as being or not-being, or both, or neither.
Then what will you do with them? I said. Can they have a better place than between being and not-being? For they are clearly not in greater darkness or negation than not-being, or more full of light and existence than being.
That is quite true, he said.
Thus then we seem to have discovered that the many ideas which the multitude entertain about the beautiful and about all other things are tossing about in some region which is half-way between pure being and pure not-being?
Yes; and we had before agreed that anything of this kind which we might find was to be described as matter of opinion, and not as matter of knowledge; being the intermediate flux which is caught and detained by the intermediate faculty.
Then those who see the many beautiful, and who yet neither see absolute beauty, nor can follow any guide who points the way thither; who see the many just, and not absolute justice, and the like,—such persons may be said to have opinion but not knowledge?
That is certain.
But those who see the absolute and eternal and immutable may be said to know, and not to have opinion only?
Neither can that be denied.
The one love and embrace the subjects of knowledge, the other those of opinion? The latter are the same, as I dare say you will remember, who listened to sweet sounds and gazed upon fair colours, but would not tolerate the existence of absolute beauty.
Yes, I remember.
Shall we then be guilty of any impropriety in calling them lovers of opinion rather than lovers of wisdom, and will they be very angry with us for thus describing them?
I shall tell them not to be angry; no man should be angry at what is true.
But those who love the truth in each thing are to be called lovers of wisdom and not lovers of opinion.