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 impression of uniformities and first principles in nature which the genius of the Greek, contemplating the expanse of heaven and earth, seemed to recognize in the distance. Nor can we deny that in ancient times knowledge must have stood still, and the human mind been deprived of the very instruments of thought, if philosophy had been strictly confined to the results of experience.
2. Plato supposes that when the tablet has been made blank the artist will fill in the lineaments of the ideal state. Is this a pattern laid up in heaven, or mere vacancy on which he is supposed to gaze with wondering eye? The answer is, that such ideals are framed partly by the omission of particulars, partly by imagination perfecting the form which experience supplies (Phaedo). Plato represents these ideals in a figure as belonging to another world; and in modern times the idea will sometimes seem to precede, at other times to co-operate with the hand of the artist. As in science, so also in creative art, there is a synthetical as well as an analytical method. One man will have the whole in his mind before he begins; to another the processes of mind and hand will be simultaneous.
3. There is no difficulty in seeing that Plato’s divisions of knowledge are based, first, on the fundamental antithesis of sensible and intellectual which pervades the whole pre-Socratic philosophy; in which is implied also the opposition of the permanent and transient, of the universal and particular. But the age of philosophy in which he lived seemed to require a further distinction;—numbers and figures were beginning to separate from ideas. The world could no longer regard justice as a cube, and was learning to see, though imperfectly, that the abstractions of sense were distinct from the abstractions of mind. Between the Eleatic being or essence and the shadows of phenomena, the Pythagorean principle of number found a place, and was, as Aristotle remarks, a conducting medium from one to the other. Hence Plato is led to introduce a third term which had not hitherto entered into the scheme of his philosophy. He had observed the use of mathematics in education; they were the best preparation for higher studies. The subjective relation between them further suggested an objective one; although the passage from one to the other is really imaginary (Metaph.). For metaphysical and moral philosophy has no connexion with mathematics; number and figure are the abstractions of time and space, not the expressions of purely intellectual conceptions. When divested of metaphor, a straight line or a square has no more to do with right and justice than a crooked line with vice. The figurative association was mistaken for a real one; and thus the three latter divisions of the Platonic proportion were constructed.
There is more difficulty in comprehending how he arrived at the first term of the series, which is nowhere else mentioned, and has no reference to any other part of his system. Nor indeed does the relation of shadows to objects correspond to the relation of numbers to ideas. Probably Plato has been led by the love of analogy (Timaeus) to make four terms instead of three, although the objects perceived in both divisions of the lower sphere are equally objects of sense. He is also preparing the way, as his manner is, for the shadows of images at the beginning of the seventh book, and the imitation of an imitation in the tenth. The line may be regarded as reaching from unity to infinity, and is divided into two unequal parts, and subdivided into two more; each lower sphere is the multiplication of the preceding. Of the four faculties, faith in the lower division has an intermediate position (cp. for the use of the word faith or belief, (Greek), Timaeus), contrasting equally with the vagueness of the perception of shadows (Greek) and the higher certainty of understanding (Greek) and reason (Greek).
The difference between understanding and mind or reason (Greek) is analogous to the difference between acquiring knowledge in the parts and the contemplation of the whole. True knowledge is a whole, and is at rest; consistency and universality are the tests of truth. To this self-evidencing knowledge of the whole the faculty of mind is supposed to correspond. But
