I pass now from Sokrates to Plato. It is true, as we read in the Analysis, ([p. 271]) that Plato “was so deeply struck with the importance of Classification, that he seems to have regarded it as the sum of all philosophy.” But what Plato thus admired was not the Classification that he found prevalent around him, such as this chapter of the Analysis depicts. Here Plato perfectly agreed with Sokrates. Among his immortal dialogues, several of the very best are devoted to the illustration of the Sokratic point of view: to the cross-examination and exposure of the minds around him, instructed as well as vulgar, in respect to the general terms familiarly used in speech. The Platonic questions and answers are framed to shew how little the respondents understand beneath those current generalities on which every one talks with confidence and fluency—and how little they can avoid contradiction or inconsistency, when their class-terms are confronted with particulars. In fact, Plato goes so far as to intimate that these uncertified classifications,—generated in each man’s mind by merely learning the application of words, and imbibed unconsciously, without special teaching, through the contagion of ordinary society—are rather worse than ignorance: inasmuch as they are accompanied by a false persuasion of knowledge. It would be (in the opinion of Plato) a comparative improvement, if this state of mental confusion, creating a false persuasion of knowledge, were broken up; and if there were substituted in place thereof positive ignorance, together with the naked and painful consciousness of being really ignorant. Only in this way could the mind of the learner be stimulated to active effort in the acquisition of genuine knowledge.[i]
[i] Plato, Sophistes, p. 230—231. Symposion, p. 204 A, Menon p. 84, A. D.
Accordingly, when it is said that Plato was “deeply struck 280 with the importance of Classification,” we must understand the phrase as applying to Classification, not as he found it prevalent, but as he idealized it. And the scheme that he imagined was not merely different from that which he found, but in direct repugnance to it. He denounced altogether the aggregate of individuals; he declared the class-constituent to reside in a reality apart from them, separate and self-existent—the Idea or Form. He enjoined the student of philosophy to fix his contemplation on these Class-Ideas, the real Realities, in their own luminous region: and for that purpose, to turn his back upon the phenomenal particulars, which were mere transitory, shadowy, incoherent projections of these Ideas[j]—and from the study of which no true knowledge could be obtained. Of the two statements in the Analysis—([p. 271]) that “Plato never dreamed of the mystical visions of his successors,” and that “his error (respecting Classification) lay in misconceiving the One; which he took, not for the aggregate, but something pervading the aggregate”—neither one nor the other appears to me accurate. In regard to the second of the two, indeed, you may find various passages of Plato which, if construed separately, would countenance it: for Plato does not always talk Realism—nor always consistently with himself. But still his capital and peculiar theory was, Realism. The Platonic One was not something pervading the aggregate of particulars, but an independent and immutable reality, apart from the aggregate: and Plato, when he thus conceived 281 the One, illustrating it by the vast hypotheses embodied in the Republic, Phædon, Phædrus, Symposion, Menon, &c., is the true originator of those “mystical visions” against which the Analysis justly protests. Such visions were doubtless suggested to Plato by “his deep sense of the importance of Classification:” but they are his own, though continued and amplified, without his decorative genius, by Neo-Platonic successors. His theory of classification was the first ever propounded; and that theory was Realism. The doctrine here ascribed to him by Mr. James Mill is much more Aristotelian than Platonic. The main issue raised by Aristotle against Plato was, upon the essential separation, and separate objective existence, of the Abstract and Universal: Plato affirmed it, Aristotle denied it.[k] Aristotle recognised no reality apart from the Particular, to which the Universal was attached as a predicate, either essential or accidental to its subject. The Aristotelian Universal may thus be called, in relation to a body of similar particulars, not the aggregate but something pervading the aggregate. But this is not Plato’s view: it is the negation of the Platonic Realism.
[j] This is what we read in the memorable simile of the Cave, in Plato, Republic, VII., p. 514—519. The language used throughout this simile is περιάγειν, περιακτίον, περιαγωγή, &c. He supposes that the natural state of man is to have his face and vision towards the particular phenomena, and his back towards the universal realities: the great problem is, how to make the man face about, turn his back towards phenomena, and his eyes towards Universals—τὰ ὄντα—τὰ νοητά. Nothing can be learnt from observation however acute, of the phenomena. The same point is enforced with all the charm of Platonic expression in Republ. V. 478, 479, VI., 493, 494. Symposion, p. 210—211, Phædon, p. 74—75.
[k] According to Plato, it is τὸ ἓν παρὰ τὰ πολλά. According to Aristotle, it is ἓν κατὰ πολλῶν—ἓν καὶ τὸ αὐτὸ ἐπὶ πλειόνων μὴ ὁμώνυμον ἓν ἐπὶ πολλῶν. Analyt. Poster. I. 11, p. 77, a. 6. Metaphys. I. 9, p. 990, b. 7—13.
Whoever reads the portions of Plato’s dialogues indicated in my last preceding foot note, will see how material this difference is between the two philosophers.
In the remarkable passage of the Analyt. Post. I. 24, p. 85, a. 30, b. 20, Aristotle notices the Platonic hypothesis that the Universal has real objective, separate, existence apart from its particulars (τὸ καθόλου ἐπὶ τι παρὰ τὰ καθ’ ἕκαστα) as an illusion, mischievous and misleading—frequent, but not unavoidable.
See the antithesis between Plato and Aristotle, on the subject of Universals, more copiously explained in the recent work of Professor Bain, Mental and Moral Science, Appendix, pp. 6—20.
When we read in the Analysis ([p. 265]) that “the word man is not a word having a very simple idea, as was the opinion of the Realists; nor a word having no idea at all, as was that of the Nominalists” this language seems to me not well-chosen. 282 As to the Realists—the Platonic Ideas are conceived as eternal, immutable, grand, dignified, &c., but Aristotle[l] contends that they cannot all be simple: for the Idea of Man (e.g.) can hardly be simple, when there exists distinct Ideas of Animal and of Biped. As to the Nominalists—we cannot surely say that they conceived the universal term as “having no idea at all.” A doctrine something like this is ascribed (on no certain testimony) to Stilpon, in the generation succeeding Aristotle: the word Man (Stilpon is said to have affirmed[m]) did not mean John more than William or Thomas or Richard, &c., therefore it did not mean either one of them: therefore it had no meaning at all. So also William of Ockham is said to have declared that Universal Terms were mere “flatus vocis:” but this (as Prantl has shewn[n]) was a phrase fastened upon him by his opponents, not employed by himself. Still less can it be admitted that Hobbes and Berkeley conceived the Universal Term as “having no idea at all.” They denied indeed Universal Ideas in the Realistic sense: they also denied what Berkeley calls “determinate abstract Ideas:” but both of them explained (Berkeley especially) that the Universal term meant, any particular idea, considered as representing or standing for all other particular ideas of the same sort.[o] Whether this be the best and most complete explanation or not, it can hardly have been present to Mr. James Mill’s mind, when he said that the Universal term had no idea at all in the opinion of the Nominalists.
[l] Aristot. Metaphys. Z. 1039, a. 27, 1040, a. 23.