Ancient and modern philosophy throw a light upon one another: but they should be compared, not confounded. Although the connexion between them is sometimes accidental, it is often real. The same questions are discussed by them under different conditions of language and civilization; but in some cases a mere word has survived, while nothing or hardly anything of the pre-Socratic, Platonic, or Aristotelian meaning is retained. There are other questions familiar to the moderns, which have no place in ancient philosophy. The world has grown older in two thousand years, and has enlarged its stock of ideas and methods of reasoning. Yet the germ of modern thought is found in ancient, and we may claim to have inherited, notwithstanding many accidents of time and place, the spirit of Greek philosophy. There is, however, no continuous growth of the one into the other, but a new beginning, partly artificial, partly arising out of the questionings of the mind itself, and also receiving a stimulus from the study of ancient writings.
Considering the great and fundamental differences which exist in ancient and modern philosophy, it seems best that we should at first study them separately, and seek for the interpretation of either, especially of the ancient, from itself only, comparing the same author with himself and with his contemporaries, and with the general state of thought and feeling prevalent in his age. Afterwards comes the remoter light which they cast on one another. We begin to feel that the ancients had the same thoughts as ourselves, the same difficulties which characterize all periods of transition, almost the same opposition between science and religion. Although we cannot maintain that ancient and modern philosophy are one and continuous (as has been affirmed with more truth respecting ancient and modern history), for they are separated by an interval of a thousand years, yet they seem to recur in a sort of cycle, and we are surprised to find that the new is ever old, and that the teaching of the past has still a meaning for us.
III. In the preface to the first edition I expressed a strong opinion at variance with Mr. Grote's, that the so-called Epistles of Plato were spurious. His friend and editor, Professor Bain, thinks that I ought to give the reasons why I differ from so eminent an authority. Reserving the fuller discussion of the question for another place, I will shortly defend my opinion by the following arguments:—
(a) Because almost all epistles purporting to be of the classical age of Greek literature are forgeries. (Compare Bentley's Works (Dyce's Edition).) Of all documents this class are the least likely to be preserved and the most likely to be invented. The ancient world swarmed with them; the great libraries stimulated the demand for them; and at a time when there was no regular publication of books, they easily crept into the world.
(b) When one epistle out of a number is spurious, the remainder of the series cannot be admitted to be genuine, unless there be some independent ground for thinking them so: when all but one are spurious, overwhelming evidence is required of the genuineness of the one: when they are all similar in style or motive, like witnesses who agree in the same tale, they stand or fall together. But no one, not even Mr. Grote, would maintain that all the Epistles of Plato are genuine, and very few critics think that more than one of them is so. And they are clearly all written from the same motive, whether serious or only literary. Nor is there an example in Greek antiquity of a series of Epistles, continuous and yet coinciding with a succession of events extending over a great number of years.
The external probability therefore against them is enormous, and the internal probability is not less: for they are trivial and unmeaning, devoid of delicacy and subtlety, wanting in a single fine expression. And even if this be matter of dispute, there can be no dispute that there are found in them many plagiarisms, inappropriately borrowed, which is a common note of forgery. They imitate Plato, who never imitates either himself or any one else; reminiscences of the Republic and the Laws are continually recurring in them; they are too like him and also too unlike him, to be genuine (see especially Karsten, Commentio Critica de Platonis quae feruntur Epistolis). They are full of egotism, self-assertion, affectation, faults which of all writers Plato was most careful to avoid, and into which he was least likely to fall. They abound in obscurities, irrelevancies, solecisms, pleonasms, inconsistencies, awkwardnesses of construction, wrong uses of words. They also contain historical blunders, such as the statement respecting Hipparinus and Nysaeus, the nephews of Dion, who are said to 'have been well inclined to philosophy, and well able to dispose the mind of their brother Dionysius in the same course,' at a time when they could not have been more than six or seven years of age— also foolish allusions, such as the comparison of the Athenian empire to the empire of Darius, which show a spirit very different from that of Plato; and mistakes of fact, as e.g. about the Thirty Tyrants, whom the writer of the letters seems to have confused with certain inferior magistrates, making them in all fifty-one. These palpable errors and absurdities are absolutely irreconcileable with their genuineness. And as they appear to have a common parentage, the more they are studied, the more they will be found to furnish evidence against themselves. The Seventh, which is thought to be the most important of these Epistles, has affinities with the Third and the Eighth, and is quite as impossible and inconsistent as the rest. It is therefore involved in the same condemnation.—The final conclusion is that neither the Seventh nor any other of them, when carefully analyzed, can be imagined to have proceeded from the hand or mind of Plato. The other testimonies to the voyages of Plato to Sicily and the court of Dionysius are all of them later by several centuries than the events to which they refer. No extant writer mentions them older than Cicero and Cornelius Nepos. It does not seem impossible that so attractive a theme as the meeting of a philosopher and a tyrant, once imagined by the genius of a Sophist, may have passed into a romance which became famous in Hellas and the world. It may have created one of the mists of history, like the Trojan war or the legend of Arthur, which we are unable to penetrate. In the age of Cicero, and still more in that of Diogenes Laertius and Appuleius, many other legends had gathered around the personality of Plato,—more voyages, more journeys to visit tyrants and Pythagorean philosophers. But if, as we agree with Karsten in supposing, they are the forgery of some rhetorician or sophist, we cannot agree with him in also supposing that they are of any historical value, the rather as there is no early independent testimony by which they are supported or with which they can be compared.
IV. There is another subject to which I must briefly call attention, lest I should seem to have overlooked it. Dr. Henry Jackson, of Trinity College, Cambridge, in a series of articles which he has contributed to the Journal of Philology, has put forward an entirely new explanation of the Platonic 'Ideas.' He supposes that in the mind of Plato they took, at different times in his life, two essentially different forms:—an earlier one which is found chiefly in the Republic and the Phaedo, and a later, which appears in the Theaetetus, Philebus, Sophist, Politicus, Parmenides, Timaeus. In the first stage of his philosophy Plato attributed Ideas to all things, at any rate to all things which have classes or common notions: these he supposed to exist only by participation in them. In the later Dialogues he no longer included in them manufactured articles and ideas of relation, but restricted them to 'types of nature,' and having become convinced that the many cannot be parts of the one, for the idea of participation in them he substituted imitation of them. To quote Dr. Jackson's own expressions,—'whereas in the period of the Republic and the Phaedo, it was proposed to pass through ontology to the sciences, in the period of the Parmenides and the Philebus, it is proposed to pass through the sciences to ontology': or, as he repeats in nearly the same words,— 'whereas in the Republic and in the Phaedo he had dreamt of passing through ontology to the sciences, he is now content to pass through the sciences to ontology.'
This theory is supposed to be based on Aristotle's Metaphysics, a passage containing an account of the ideas, which hitherto scholars have found impossible to reconcile with the statements of Plato himself. The preparations for the new departure are discovered in the Parmenides and in the Theaetetus; and it is said to be expressed under a different form by the (Greek) and the (Greek) of the Philebus. The (Greek) of the Philebus is the principle which gives form and measure to the (Greek); and in the 'Later Theory' is held to be the (Greek) or (Greek) which converts the Infinite or Indefinite into ideas. They are neither (Greek) nor (Greek), but belong to the (Greek) which partakes of both.
With great respect for the learning and ability of Dr. Jackson, I find myself unable to agree in this newly fashioned doctrine of the Ideas, which he ascribes