Plato's Republic is an influential work of philosophy and political theory by the Greek philosopher Plato, written in approximately 360 BC. It is written in the format of a Socratic dialogue.

Plato's Republic uses the sun as a metaphor for the source of "illumination", arguably intellectual illumination, which he held to be The Form of the Good, which is sometimes interpreted as Plato's notion of God. The metaphor is about the nature of ultimate reality and how we come to know it. (Socrates is the speaker of The Republic, but it is generally believed that the thoughts expressed are Plato's.)



The eye, Plato says, is unusual among the sense organs in that it needs a medium, namely light, in order to operate. The strongest and best source of light is the sun; with it, we can discern objects clearly. Analogous things, he writes, can be said of intelligible objects (i.e., the fixed and eternal forms that are the ultimate objects of scientific and philosophical study):

When [the soul] is firmly fixed on the domain where truth and reality shine resplendent it apprehends and knows them and appears to possess reason, but when it inclines to that region which is mingled with darkness, the world of becoming and passing away, it opines only and its edge is blunted, and it shifts its opinions hither and thither, and again seems as if it lacked reason.

By "the world of becoming and passing away" Plato means the familiar visual or perceptual world we see around us. Thus if we attempt to understand why things are as they are, and what general categories can be used to understand various particulars around us, without reference to any forms (universals), we will fail completely, as if [we] lacked reason. By contrast, "the domain where truth and reality shine resplendent" is none other than Plato's world of forms--illuminated by the highest of the forms, that of the Good. Since true being resides in the world of the forms, we must direct our intellects there to have knowledge, in Plato's view; otherwise, we are stuck with mere opinion of what may be likened to passing shadows.

Plato also says the sun and the Good ("the object of knowledge") are both sources of "generation":

The sun ... not only furnishes to visible the power of visibility but it also provides for their generation and growth and nurture though it is not itself generation. ... In like manner, then ... the objects of knowledge not only receive from the presence of the good their being known, but their very existence and essence is derived to them from it, though the good itself is not essence but still transcends essence in dignity and surpassing power.

This is one of the passages that leads some to infer that the Good is, for Plato, God, though there is some dispute about this point. Many modern readers will find it puzzling that one and the same thing is called the Good, the source of being (the being of the forms, at least), something that (somehow) sheds light on all other forms, and a universal. Indeed, exactly how it is Plato thinks "very existence and essence is derived to [the forms] from" the Good is a matter of considerable interpretive difficulty. This doctrine conveyed by the metaphor of the sun is, incidentally, an excellent example of how, traditionally, the subjects of metaphysics and epistemology have been closely intertwined: accounts of what exists, at a fundamental level, often deeply inform (and are informed by) accounts of ways or kinds of knowing. It also neatly sums up two views for which Plato is well-known: his rationalism and his realism (about universals).

Plato goes on to describe the levels of reality and knowledge with the device of the so-called "divided line" (509d-513e). Immediately afterwards, at the beginning of Book VII, the same doctrine is elaborated using the famous allegory of the cave.

Plato's Republic is the supreme product of Plato's most mature years, thought, and style. It contains virtually the entire universe of Plato's philosophy.

Plato's Allegory of the Cave is an allegory used by Plato in The Republic. The Allegory of the Cave is told and then interpreted by the character Socrates at the beginning of Book 7. It is related to Plato's metaphor of the sun and the analogy of the divided line. Allegories are summarized in the viewpoint of dialectic at the end of book VII.

Imagine prisoners, who have been chained since their childhood deep inside a cave: not only are their limbs immobilized by the chains; their heads are chained as well, so that their gaze is fixed on a wall. Behind the prisoners is an enormous fire, and between the fire and the prisoners is a raised walkway, along which statues of various animals, plants, and other things are carried by people. The statues cast shadows on the wall, and the prisoners watch these shadows. When one of the statue-carriers speaks, an echo against the wall causes the prisoners to believe that the words come from the shadows.

The prisoners engage in what appears to us to be a game: naming the shapes as they come by. This, however, is the only reality that they know, even though they are seeing merely shadows of images. They are thus conditioned to judge the quality of one another by their skill in quickly naming the shapes and dislike those who begin to play poorly.

Suppose a prisoner is released and compelled to stand up and turn around. At that moment his eyes will be blinded by the sunlight coming into the cave from its entrance, and the shapes passing will appear less real than their shadows.

The last object he would be able to see is the sun, which, in time, he would learn to see as that object which provides the seasons and the courses of the year, presides over all things in the visible region, and is in some way the cause of all these things that he has seen.

Once enlightened, so to speak, the freed prisoner would not want to return to the cave to free "his fellow bondsmen," but would be compelled to do so. Another problem lies in the other prisoners not wanting to be freed: descending back into the cave would require that the freed prisoner's eyes adjust again, and for a time, he would be one of the ones identifying shapes on the wall. His eyes would be swamped by the darkness, and would take time to become acclimated. Therefore, he would not be able to identify shapes on the wall as well as the other prisoners, making it seem as if his being taken to the surface completely ruined his eyesight.

Interpretation

Socrates himself interprets the allegory (beginning at 517b): "This image then [the allegory of the cave] we must apply as a whole to all that has been said"Ñi.e. the preceding analogy of the divided line and metaphor of the sun. It has been up to scholarly debate in 20th century how exactly these three sequential comparisons can be coherently bound together. Main problems arise from allegory of cave having three cognitive stages and divided line having four of them where the first division (shadows, reflections) seems not to be needed to apply to cave and is hard to be interpreted ontologically, i.e. in the manner of cave at all. Metaphor of the sun seems to be alluding that from seeing things in light of sun we can raise to seeing ideas in the light of the Good while in cave it is not evident that it can not be done without considerably violent helping and forcing prisoners to look at light.

Plato's own remarks on the allegory

In particular, Plato likens "the region revealed through sight"Ñthe ordinary objects we see around us - "to the habitation of the prison, and the light of the fire in it to the power of the sun. And if you assume the ascent and the contemplation of the things above is the soul's ascension to the intelligible region, you will not miss my surmise...[M]y dream as it appears to me is that in the region of the known the last thing to be seen and hardly seen is the idea of good, and that when seen, it must point us to the conclusion that this is indeed the cause for all things of all that is right and beautiful, giving birth in the visible world to light, and the author of light and itself in the intelligible world being the authentic source of truth and reason...". After "returning from divine contemplations to the petty miseries of men", one is apt to cut "a sorry figure" if, "while still blinking through the gloom, and before he has become sufficiently accustomed to the environing darkness, he is compelled in courtrooms or elsewhere to contend about the shadows of justice or the images that cast the shadows and to wrangle in debate about the notions of these things in the minds of those who have never seen justice itself?"

Interpretation of the idealist tradition

Another interpretation is that of the Idealists. As in the philosophy of George Berkeley, it is understood that we do not directly and immediately know real external objects; we only directly know the effect that reality has on our minds. In other words, we immediately know only shadowy inner mental images of real external objects. The real external objects themselves cannot be immediately and directly known. In the Appendix to his main work, Arthur Schopenhauer expressed it as follows:

This world that appears to the senses has no true being, but only a ceaseless becoming; it is, and it also is not; and its comprehension is not so much a knowledge as an illusion. This is what he expresses in a myth at the beginning of the seventh book of the Republic, the most important passage in all his works É . He says that men, firmly chained in a dark cave, see neither the genuine original light nor actual things, but only the inadequate light of the fire in the cave, and the shadows of actual things passing by the fire behind their backs. Yet they imagine that the shadows are the reality, and that determining the succession of these shadows is true wisdom.
Different Grounds for Interpretation

One can also choose whether the meaning of allegory is epistemological or ontological, i.e. are the shadows to be correlated with things in our world of sight, the things in cave with mathematical entities, and things outside cave with ideas or should we just concentrate on the cognitive stages. It has been claimed that purely epistemological view is foreign to Greek tradition and especially Plato, that is the reading should bring ontological statements within.

Besides cognitive interpretations the allegory has also clear political implications, for example the fourth stage of returning to cave to help fellow-prisoners. Also the play of shadows can be interpreted as political juggling over citizens heads and this seems to be natural because of the whole context of Republic. Since the highest knowledge in allegory is The Good then the interpretation should bring together at least ethical allusions about attaining virtues. However, Plato himself introduces the allegory of cave letting Socrates say that it is about education (paideia) and miseducatedness (apaideusia).

Movements between stages

Since allegory is by Socrates' words about education, it should be interpreted from the viewpoint of conditions for taking steps toward higher stages, i.e. conditions for education.

There are four steps described:

• prisoners who think that shadows are reality;
• prisoners who are freed and forced to look at the things that are used to cast shadows on the wall and do not recognize these as sources for shadows;
• prisoners who are freed and dragged along to the outside of cave;
• free men returning to the cave to former fellow-prisoners.

  Step (3) has also four sub-steps of looking at:

  • shadows,
  • things that cast shadows,
  • heavenly bodies,
  • sun as the source and guarantee of all the things outside cave.

  Substeps beneath step (3) cohere notably with analogy of the divided line. Confrontation between cave and outside can be explained by metaphor of sun, but there is one major difference: in the cave one cannot deduce from whatever position that burning artificial light and things that are carried are the source for shadows. Metaphor of the sun argues but that this kind of deduction is possible.

  All the steps have their proper interpretation from ontological, epistemological and ethical point of view.

(Metaphors: 'Cave' represents the Mind or Human Consciousness. 'Prisoners' represent the human experiment.)

Analogy of the divided line -- Plato, in his dialogue The Republic Book 6 (509D - 513E), has Socrates explain the literary device of a divided line to teach basic philosophical views about four levels of existence (especially "the intelligible" world of the forms, universals, and "the visible" world we see around us) and the corresponding ways we come to know what exists.

In metaphysics, a universal is a type, a property, or a relation. The noun universal contrasts with individual, while the adjective universal contrasts with particular or sometimes with concrete. The latter meaning, however, may be confusing since Hegelian and neo-Hegelian (e.g. British idealist) philosophies speak of concrete universals.

A universal may have instances, known as its particulars. For example, the type dog (or doghood) is a universal, as are the property red (or redness) and the relation betweenness (or being between). Any particular dog, red thing, or object that is between other things is not a universal, however, but is an instance of a universal. That is, a universal type (doghood), property (redness), or relation (betweenness) inheres a particular object (a specific dog, red thing, or object between other things).

Platonic Realism holds universals to be the referents of general terms, i.e. the abstract, nonphysical entities to which words like "doghood", "redness", and "betweenness" refer. By contrast, particulars are the referents of proper names, like "Fido", or of definite descriptions that identify single objects, like the phrase, "that apple on the table". By contrast, other metaphysical theories merely use the terminology of universals to describe physical entities. Plato also gives examples of mathematical and geometrical ideas such as a circle and natural numbers as universals. Plato referred to the perfect circle as the form or blueprint for all copies and for the word definition of the circle.

Some ancient philosophers have held the notion that universal questions exist for all, or most humans, everywhere, and throughout history. Some of these universal questions are: What exists? What can we know? What should we do? What is after death?

The problem of universals is an ancient problem in metaphysics concerning the nature of universals, or whether they exist. Part of the problem involves the implications of language use and the complexity of relating language to ontological theory.