– no better; a man may lie on his back on land or on water – he may look up or look down, but there is no science in that. The vision of knowledge of which I speak is seen not with the eyes, but with the mind. All the magnificence of the heavens is but the embroidery of a copy which falls far short of the divine Original, and teaches nothing about the absolute harmonies or motions of things. Their beauty is like the beauty of figures drawn by the hand of Daedalus or any other great artist, which may be used for illustration, but no mathematician would seek to obtain from them true conceptions of equality or numerical relations. How ridiculous then to look for these in the map of the heavens, in which the imperfection of matter comes in everywhere as a disturbing element, marring the symmetry of day and night, of months and years, of the sun and stars in their courses. Only by problems can we place astronomy on a truly scientific basis. Let the heavens alone, and exert the intellect.
Still, mathematics admit of other applications, as the Pythagoreans say, and we agree. There is a sister science of harmonical motion, adapted to the ear as astronomy is to the eye, and there may be other applications also. Let us inquire of the Pythagoreans about them, not forgetting that we have an aim higher than theirs, which is the relation of these sciences to the idea of good. The error which pervades astronomy also pervades harmonics. The musicians put their ears in the place of their minds. 'Yes,' replied Glaucon, 'I like to see them laying their ears alongside of their neighbours' faces – some saying, "That's a new note," others declaring that the two notes are the same.' Yes, I said; but you mean the empirics who are always twisting and torturing the strings of the lyre, and quarrelling about the tempers of the strings; I am referring rather to the Pythagorean harmonists, who are almost equally in error. For they investigate only the numbers of the consonances which are heard, and ascend no higher, – of the true numerical harmony which is unheard, and is only to be found in problems, they have not even a conception. 'That last,' he said, 'must be a marvellous thing.' A thing, I replied, which is only useful if pursued with a view to the good.
All these sciences are the prelude of the strain, and are profitable if they are regarded in their natural relations to one another. 'I dare say, Socrates,' said Glaucon; 'but such a study will be an endless business.' What study do you mean – of the prelude, or what? For all these things are only the prelude, and you surely do not suppose that a mere mathematician is also a dialectician? 'Certainly not. I have hardly ever known a mathematician who could reason.' And yet, Glaucon, is not true reasoning that hymn of dialectic which is the music of the intellectual world, and which was by us compared to the effort of sight, when from beholding the shadows on the wall we arrived at last at the images which gave the shadows? Even so the dialectical faculty withdrawing from sense arrives by the pure intellect at the contemplation of the idea of good, and never rests but at the very end of the intellectual world. And the royal road out of the cave into the light, and the blinking of the eyes at the sun and turning to contemplate the shadows of reality, not the shadows of an image only – this progress and gradual acquisition of a new faculty of sight by the help of the mathematical sciences, is the elevation of the soul to the contemplation of the highest ideal of being.
'So far, I agree with you. But now, leaving the prelude, let us proceed to the hymn. What, then, is the nature of dialectic, and what are the paths which lead thither?' Dear Glaucon, you cannot follow me here. There can be no revelation of the absolute truth to one who has not been disciplined in the previous sciences. But that there is a science of absolute truth, which is attained in some way very different from those now practised, I am confident. For all other arts or sciences are relative to human needs and opinions; and the mathematical sciences are but a dream or hypothesis of true being, and never analyse their own principles. Dialectic alone rises to the principle which is above hypotheses, converting and gently leading the eye of the soul out of the barbarous slough of ignorance into the light of the upper world, with the help of the sciences which we have been describing – sciences, as they are often termed, although they require some other name, implying greater clearness than opinion and less clearness than science, and this in our previous sketch was understanding. And so we get four names – two for intellect, and two for opinion, – reason or mind, understanding, faith, perception of shadows – which make a proportion – being: becoming::intellect: opinion – and science: belief::understanding: perception of shadows. Dialectic may be further described as that science which defines and explains the essence or being of each nature, which distinguishes and abstracts the good, and is ready to do battle against all opponents in the cause of good. To him who is not a dialectician life is but a sleepy dream; and many a man is in his grave before his is well waked up. And would you have the future rulers of your ideal State intelligent beings, or stupid as posts? 'Certainly not the latter.' Then you must train them in dialectic, which will teach them to ask and answer questions, and is the coping-stone of the sciences.
I dare say that you have not forgotten how our rulers were chosen; and the process of selection may be carried a step further: – As before, they must be constant and valiant, good-looking, and of noble manners, but now they must also have natural ability which education will improve; that is to say, they must be quick at learning, capable of mental toil, retentive, solid, diligent natures, who combine intellectual with moral virtues; not lame and one-sided, diligent in bodily exercise and indolent in mind, or conversely; not a maimed soul, which hates falsehood and yet unintentionally is always wallowing in the mire of ignorance; not a bastard or feeble person, but sound in wind and limb, and in perfect condition for the great gymnastic trial of the mind. Justice herself can find no fault with natures such as these; and they will be the saviours of our State; disciples of another sort would only make philosophy more ridiculous than she is at present. Forgive my enthusiasm; I am becoming excited; but when I see her trampled underfoot, I am angry at the authors of her disgrace. 'I did not notice that you were more excited than you ought to have been.' But I felt that I was. Now do not let us forget another point in the selection of our disciples – that they must be young and not old. For Solon is mistaken in saying that an old man can be always learning; youth is the time of study, and here we must remember that the mind is free and dainty, and, unlike the body, must not be made to work against the grain. Learning should be at first a sort of play, in which the natural bent is detected. As in training them for war, the young dogs should at first only taste blood; but when the necessary gymnastics are over which during two or three years divide life between sleep and bodily exercise, then the education of the soul will become a more serious matter. At twenty years of age, a selection must be made of the more promising disciples, with whom a new epoch of education will begin. The sciences which they have hitherto learned in fragments will now be brought into relation with each other and with true being; for the power of combining them is the test of speculative and dialectical ability. And afterwards at thirty a further selection shall be made of those who are able to withdraw from the world of sense into the abstraction of ideas. But at this point, judging from present experience, there is a danger that dialectic may be the source of many evils. The danger may be illustrated by a parallel case: – Imagine a person who has been brought up in wealth and luxury amid a crowd of flatterers, and who is suddenly informed that he is a supposititious son. He has hitherto honoured his reputed parents and disregarded the flatterers, and now he does the reverse. This is just what happens with a man's principles. There are certain doctrines which he learnt at home and which exercised a parental authority over him. Presently he finds that imputations are cast upon them; a troublesome querist comes and asks, 'What is the just and good?' or proves that virtue is vice and vice virtue, and his mind becomes unsettled, and he ceases to love, honour, and obey them as he has hitherto done. He is seduced into the life of pleasure, and becomes a lawless person and a rogue. The case of such speculators is very pitiable, and, in order that our thirty years' old pupils may not require this pity, let us take every possible care that young persons do not study philosophy too early. For a young man is a sort of puppy who only plays with an argument; and is reasoned into and out of his opinions every day; he soon begins to believe nothing, and brings himself and philosophy into discredit. A man of thirty does not run on in this way; he will argue and not merely contradict, and adds new honour to philosophy by the sobriety of his conduct. What time shall we allow for this second gymnastic training of the soul? – say, twice the time required for the gymnastics of the body; six, or perhaps five years, to commence at thirty, and then for fifteen years let the student go down into the den, and command armies,
