Adeimantus objects first of all to the form of the Socratic reasoning, thus showing that Plato is aware of the imperfection of his own method. He brings the accusation against himself which might be brought against him by a modern logician – that he extracts the answer because he knows how to put the question. In a long argument words are apt to change their meaning slightly, or premises may be assumed or conclusions inferred with rather too much certainty or universality; the variation at each step may be unobserved, and yet at last the divergence becomes considerable. Hence the failure of attempts to apply arithmetical or algebraic formulae to logic. The imperfection, or rather the higher and more elastic nature of language, does not allow words to have the precision of numbers or of symbols. And this quality in language impairs the force of an argument which has many steps.
The objection, though fairly met by Socrates in this particular instance, may be regarded as implying a reflection upon the Socratic mode of reasoning. And here, as elsewhere, Plato seems to intimate that the time had come when the negative and interrogative method of Socrates must be superseded by a positive and constructive one, of which examples are given in some of the later dialogues. Adeimantus further argues that the ideal is wholly at variance with facts; for experience proves philosophers to be either useless or rogues. Contrary to all expectation Socrates has no hesitation in admitting the truth of this, and explains the anomaly in an allegory, first characteristically depreciating his own inventive powers. In this allegory the people are distinguished from the professional politicians, and, as elsewhere, are spoken of in a tone of pity rather than of censure under the image of 'the noble captain who is not very quick in his perceptions.'
The uselessness of philosophers is explained by the circumstance that mankind will not use them. The world in all ages has been divided between contempt and fear of those who employ the power of ideas and know no other weapons. Concerning the false philosopher, Socrates argues that the best is most liable to corruption; and that the finer nature is more likely to suffer from alien conditions. We too observe that there are some kinds of excellence which spring from a peculiar delicacy of constitution; as is evidently true of the poetical and imaginative temperament, which often seems to depend on impressions, and hence can only breathe or live in a certain atmosphere. The man of genius has greater pains and greater pleasures, greater powers and greater weaknesses, and often a greater play of character than is to be found in ordinary men. He can assume the disguise of virtue or disinterestedness without having them, or veil personal enmity in the language of patriotism and philosophy, – he can say the word which all men are thinking, he has an insight which is terrible into the follies and weaknesses of his fellow-men. An Alcibiades, a Mirabeau, or a Napoleon the First, are born either to be the authors of great evils in states, or 'of great good, when they are drawn in that direction.'
Yet the thesis, 'corruptio optimi pessima,' cannot be maintained generally or without regard to the kind of excellence which is corrupted. The alien conditions which are corrupting to one nature, may be the elements of culture to another. In general a man can only receive his highest development in a congenial state or family, among friends or fellow-workers. But also he may sometimes be stirred by adverse circumstances to such a degree that he rises up against them and reforms them. And while weaker or coarser characters will extract good out of evil, say in a corrupt state of the church or of society, and live on happily, allowing the evil to remain, the finer or stronger natures may be crushed or spoiled by surrounding influences – may become misanthrope and philanthrope by turns; or in a few instances, like the founders of the monastic orders, or the Reformers, owing to some peculiarity in themselves or in their age, may break away entirely from the world and from the church, sometimes into great good, sometimes into great evil, sometimes into both. And the same holds in the lesser sphere of a convent, a school, a family.
Plato would have us consider how easily the best natures are overpowered by public opinion, and what efforts the rest of mankind will make to get possession of them. The world, the church, their own profession, any political or party organization, are always carrying them off their legs and teaching them to apply high and holy names to their own prejudices and interests. The 'monster' corporation to which they belong judges right and truth to be the pleasure of the community. The individual becomes one with his order; or, if he resists, the world is too much for him, and will sooner or later be revenged on him. This is, perhaps, a one-sided but not wholly untrue picture of the maxims and practice of mankind when they 'sit down together at an assembly,' either in ancient or modern times.
When the higher natures are corrupted by politics, the lower take possession of the vacant place of philosophy. This is described in one of those continuous images in which the argument, to use a Platonic expression, 'veils herself,' and which is dropped and reappears at intervals. The question is asked, – Why are the citizens of states so hostile to philosophy? The answer is, that they do not know her. And yet there is also a better mind of the many; they would believe if they were taught. But hitherto they have only known a conventional imitation of philosophy, words without thoughts, systems which have no life in them; a (divine) person uttering the words of beauty and freedom, the friend of man holding communion with the Eternal, and seeking to frame the state in that image, they have never known. The same double feeling respecting the mass of mankind has always existed among men. The first thought is that the people are the enemies of truth and right; the second, that this only arises out of an accidental error and confusion, and that they do not really hate those who love them, if they could be educated to know them.
In the latter part of the sixth book, three questions have to be considered: 1st, the nature of the longer and more circuitous way, which is contrasted with the shorter and more imperfect method of Book IV; 2nd, the heavenly pattern or idea of the state; 3rd, the relation of the divisions of knowledge to one another and to the corresponding faculties of the soul:
1. Of the higher method of knowledge in Plato we have only a glimpse. Neither here nor in the Phaedrus or Symposium, nor yet in the Philebus or Sophist, does he give any clear explanation of his meaning. He would probably have described his method as proceeding by regular steps to a system of universal knowledge, which inferred the parts from the whole rather than the whole from the parts. This ideal logic is not practised by him in the search after justice, or in the analysis of the parts of the soul; there, like Aristotle in the Nicomachean Ethics, he argues from experience and the common use of language. But at the end of the sixth book he conceives another and more perfect method, in which all ideas are only steps or grades or moments of thought, forming a connected whole which is self-supporting, and in which consistency is the test of truth. He does not explain to us in detail the nature of the process. Like many other thinkers both in ancient and modern times his mind seems to be filled with a vacant form which he is unable to realize. He supposes the sciences to have a natural order and connexion in an age when they can hardly be said to exist. He is hastening on to the 'end of the intellectual world' without even making a beginning of them.
In modern times we hardly need to be reminded that the process of acquiring knowledge is here confused with the contemplation of absolute knowledge. In all science a priori and a posteriori truths mingle in various proportions. The a priori part is that which is derived from the most universal experience of men, or is universally accepted by them; the a posteriori is that which grows up around the more general principles and becomes imperceptibly one with them. But Plato erroneously imagines that the synthesis is separable from the analysis, and that the method of science can anticipate science. In entertaining such a vision of a priori knowledge he is sufficiently justified, or at least his meaning may be sufficiently explained by the similar attempts of Descartes, Kant, Hegel, and even of Bacon himself, in modern philosophy. Anticipations or divinations, or prophetic glimpses of truths whether concerning man or nature, seem to stand in the same relation to ancient philosophy which hypotheses bear to modern inductive science. These 'guesses at truth' were not made at random; they arose from a superficial