Here then are the four grades. Two grades of Cognition — 1. Noûs, or Direct Cognition. 2. Dianoia, or Indirect Cognition: both of them belonging to the Intelligible Region, and both of them higher than Opinion. Next follow the two grades of Opinion. 3. The higher grade, Faith or Belief. 4. The lower grade, Conjecture. Both the two last belong to the sensible world; the first to real objects, the last to images of those objects.[207]
[207] Plato, Republic, p. 511 D-E.
Distinction between the philosopher and the unphilosophical public, illustrated by the simile of the Cave, and the captives imprisoned therein.
Sokrates now proceeds to illustrate the contrast between the philosopher and the unphilosophical or ordinary man, by the memorable simile of the cave and its shadows. Mankind live in a cave, with its aperture directed towards the light of the sun; but they are so chained, that their backs are constantly turned towards this aperture, so that they cannot see the sun and sunlight. What they do see is by means of a fire which is always burning behind them. Between them and this fire there is a wall; along the wall are posted men who carry backwards and forwards representations or images of all sorts of objects; so that the shadows of these objects by the firelight are projected from behind these chained men upon the ground in front of them, and pass to and fro before their vision. All the experience which such chained men acquire, consists in what they observe of the appearance and disappearance, the transition, sequences, and co-existences, of these shadows, which they mistake for truth and realities, having no no acquaintance with any other phenomena.[208] If now we suppose any one of them to be liberated from his chains, turned round, and brought up to the light of the sun and to real objects — his eyesight would be at first altogether dazzled, confounded, and distressed. Distinguishing as yet nothing clearly, he would believe that the shadows which he had seen in his former state were true and distinct objects, and that the new mode of vision to which he had been suddenly introduced was illusory and unprofitable. He would require a long time to accustom him to daylight: at first his eyes would bear nothing but shadows — next images in the water — then the stars at night — lastly, the full brightness of the Sun. He would learn that it was the Sun which not only gave light, but was the cause of varying seasons, growth, and all the productions of the visible world. And when his mind had been thus opened, he would consider himself much to be envied for the change, looking back with pity on his companions still in the cave.[209] He would think them all miserably ignorant, as being conversant not with realities, but only with the shadows which passed before their eyes. He would have no esteem even for the chosen few in the cave, who were honoured by their fellows as having best observed the co-existences and sequences among these shadows, so as to predict most exactly how the shadows would appear in future.[210] Moreover if, after having become fully accustomed to daylight and the contemplation of realities, he were to descend again into the cave, his eyesight would be dim and confused in that comparative darkness; so that he would not well recognise the shadows, and would get into disputes about them with his companions. They on their side would deride him as having spoilt his sight as well as his judgment, and would point him out as an example to deter others from emerging out of the cave into daylight.[211] Far from wishing to emerge themselves, they would kill, if they could, any one who tried to unchain them and assist them in escaping.[212]
[208] Plato, Republic, vii. pp. 514-515.
[209] Plato, Republic, vii. pp. 515-516.
[210] Plato, Republic, vii. p. 516 C. Τιμαὶ δὲ καὶ ἔπαινοι εἴ τινες αὐτοῖς ἦσαν τότε παρ’ ἀλλήλων καὶ γέρα τῷ ὀξύτατα καθορῶντι τὰ παριόντα, καὶ μνημονεύοντι μάλιστα ὅσα τε πρότερα αὐτῶν καὶ ὕστερα εἰώθει καὶ ἅμα πορεύεσθαι, καὶ ἐκ τούτων δὴ δυνατώτατα ἀπομαντευομένῳ τὸ μέλλον ἥξειν, δοκεῖς ἂν αὐτὸν ἐπιθυμητικῶς αὐτῶν ἔχειν καὶ ζηλοῦν τοὺς παρ’ ἐκείνοις τιμωμένους τε καὶ ἐνδυναστεύοντας;
[211] Plato, Republic, vii. p. 517 A. ἆρ’ οὐ γέλωτ’ ἂν παράσχοι καὶ λέγοιτο ἂν περὶ αὐτοῦ ὡς ἀναβὰς ἄνω διεφθαρμένος ἥκει τὰ ὄμματα, καὶ ὅτι οὐκ ἄξιον οὐδὲ πειρᾶσθαι ἄνω ἰέναι;
[212] Plato, Republic, vii. p. 517 A. καὶ τὸν ἐπιχειροῦντα λύειν τε καὶ ἀνάγειν, εἴ πως ἐν ταῖς χερσὶ δύναιτο λαβεῖν καὶ ἀποκτεῖναι, ἀποκτιννύναι ἂν;
Daylight of philosophy contrasted with the firelight and shadows of the Cave.