Plato: Republic

Adeimantus interposes, telling Socrates that no one can answer his statements, yet his hearers feel led astray step by step until they suffer a mighty overthrow, like unskilful draughts players shut up with no move. He reports the charge that philosophy's votaries become strange monsters or rogues, the best of them useless. Socrates asks whether those saying so are wrong; Adeimantus wants Socrates' opinion, and Socrates agrees they are right. Asked how he can then say cities will not cease from evil until philosophers rule, Socrates answers with a parable. He describes a ship whose captain is large but deaf, dim-sighted, and ignorant of navigation; the sailors quarrel over steering, drug the captain, mutiny, seize the ship, and call the true pilot a star-gazer and good-for-nothing. Socrates interprets this as the philosopher's relation to the State, blaming those who will not use him. Turning to the corruption of the majority, Socrates recalls that truth leads the philosophic nature, which strives after being and hates a lie. He explains that the philosopher's own virtues and life's goods—beauty, wealth, strength—can destroy the rare gifted nature; ill-educated, the finest become worst. The public, in assemblies, courts, and theatres, are the greatest Sophists, using confiscation and death. Hired Sophists merely learn the great beast's tempers. The flattered gifted youth is diverted; friends prevent his turning to philosophy. Philosophy, left desolate, is invaded by unworthy men, likened to a bald tinker. A small remnant remains—exiles, lofty souls, those held by Theages' bridle or Socrates' internal sign—who retire like men sheltering under a wall. Socrates says no existing government suits philosophy; Adeimantus asks whether the fitting State is the one they founded.

Still, Glaucon, I said, will you not allow us to say this much, that the good is the end of all knowledge and all being, and that the just and honourable partake of this nature, though we know not what it is? But Socrates declines to state directly what the good is. He recalls that the questioners have often heard the parent of the good, and offers to describe the child of the good instead, warning that he can speak of the offspring but not of the parent itself. Socrates then distinguishes the many beautiful things and many good things from beauty itself and goodness itself, saying the many are seen but not known by intellect, while the ideas are known by intellect but not seen. He asks by what faculty the objects of sight are perceived, and notes that sight and its objects require a third thing to bind them—light, and the lord of light in the visible world, the sun. Socrates says the sun is not sight but the cause of sight, and calls the sun the child of the good, made in the good's likeness. As the sun gives to visible things both the power of being seen and their generation and growth and nourishment, though the sun is not itself generation, so the good gives to the objects of knowledge their truth and to the knower the power of knowing, and the good is beyond being in dignity and power. Glaucon laughs at the notion of a good so exceeding, and Socrates says it was Glaucon who forced him to utter his thoughts upon it. Socrates proposes to speak of the two ruling powers, the good over the intellectual world and the sun over the visible. He describes a line divided into two unequal parts, the visible and the intelligible, and each part divided again in the same proportion. In the visible, the lower section holds images—shadows and reflections—and the higher holds the things they resemble, the animals and plants and works of nature and art. He says the two divisions differ in clearness and want of clearness, the copy standing to the original as the sphere of opinion stands to that of knowledge. Socrates then divides the intelligible. In the lower division the soul uses the objects of the visible as images and proceeds from hypotheses down to a conclusion, as in geometry and arithmetic, where students assume the odd and even and figures and angles and do not give account of them. In the higher division the soul moves from hypotheses upward to a first principle that is not hypothetical, using no images but only ideas, proceeding through ideas to ideas and ending in ideas. Glaucon says he understands, though imperfectly, that Socrates distinguishes the province of pure intellect from the objects of the arts, in which the hypotheses are assumed and the reasoning proceeds by the understanding, not the reason. Socrates assigns four faculties to the four divisions: reason to the highest, understanding to the second, faith to the third, and perception of shadows to the last; and he arranges them in proportion, each partaking of clearness according as its object partakes of truth.