Moreover, when Plato, to prove the conclusion that Intelligence and Reason are the governing attributes of man’s mind, enunciates as his premiss that Intelligence and Reason are the governing attributes in the Kosmos[95] — the premiss introduced is more debateable than the conclusion; and would (as he himself intimates) be contested by those against whose opposition he was arguing. In fact, the same proposition (That Reason and Intelligence are the dominant and controlling attributes of man, Passion and Appetite the subordinate) is assumed without any proof by Sokrates, both in the Protagoras and in the Republic. The Kosmos (in Plato’s view) has reason and intelligence, but experiences no emotion either painful or pleasurable: the rational nature of man is thus common to him with the Kosmos, his emotional nature is not so. That the mind of each individual man was an emanation from the all-pervading mind of the Kosmos or universe, and his body a fragmentary portion of the four elements composing the cosmical body — these are propositions which had been laid down by Sokrates, as well as by Philolaus and other Pythagoreans (perhaps by Pythagoras himself) before the time of Plato.[96] Not only that doctrine, but also the analysis of the Kosmos into certain abstract constituent principia — (the Finient or Determinant — and the Infinite or Indeterminate) — this too seems to have been borrowed by Plato from Philolaus.[97]
[95] Plato, Philêbus, pp. 20-30.
[96] Cicero, De Nat. Deor. i. 11, 27: De Senectute, 21, 78; Xenophon, Memor. i. 4, 7-8; Cicero, Nat. Deor. ii. 6, 18; Plato, Timæus, pp. 37-38, &c.
In the Xenophontic dialogue here referred to, Sokrates inverts the premiss and the conclusion: he infers that Mind and Reason govern the Kosmos, because the mind and reason of man govern the body of man.
[97] See Stallbaum, Prolegg. in Philêb. pp. 41-42.
Plato borrows from the Pythagoreans, but enlarges their doctrine. Importance of his views in dwelling upon systematic classification.
But here in the Philêbus, that analysis appears expanded into a larger scheme going beyond Philolaus or the Pythagoreans: viz. the recognition of a graduated scale of limits, or a definite number of species and sub-species — intermediate between the One or Highest Genus, and the Infinite Many or Individuals — and descending by successive stages of limitation from the Highest to the Lowest. What is thus described, is the general framework of systematic logical classification, deliberately contrived, and founded upon known attributes, common as well as differential. It is prescribed as essential to all real cognition; if we conceive only the highest Genus or generic name as comprehending an infinity of diverse particulars, we have no real cognition, until we can assign the intermediate stages of specification by which we descend from one to the other.[98] The step here made by Plato, under the stimulus of the Sokratic dialectic, from the Pythagorean doctrine of Finient and Infinite to the idea of gradual, systematic, logical division and subdivision, is one very important in the history of science. He lays as much stress upon the searching out of the intermediate species, as Bacon does upon the Axiomata Media of scientific enquiry.[99]
[98] Ueberweg (Æchtheit und Zeitf. Platon. Schriften, pp. 204-207) considers the Philêbus, as well as the Sophistês and Timæus, to be compositions of Plato’s very late age — partly on the ground of their didactic and expository style, the dialogue serving only as form to the exponent Sokrates — partly because he thinks that the nearest approach is made in them to that manner of conceiving the doctrine of Ideas which Aristotle ascribes to Plato in his old age — that is, the two στοιχεῖα or factors of the Ideas. 1. Τὸ ἓν. 2. Τὸ μέγα καὶ μικρόν. This last argument seems to me far-fetched. I see no real and sensible approach in the Philêbus to this Platonic doctrine of the στοιχεῖα of the Ideas: at least, the approach is so vague, that one can hardly make it a basis of reasoning. But the didactic tone is undoubtedly a characteristic of the Philêbus, and seems to indicate that the dialogue was composed after Plato had been so long established in his school, as to have acquired a pedagogic ostentation.
[99] Bacon, Augment. Scient. v. 2. Nov. Organ. Aph. 105. “At Plato non semel innuit particularia infinita esse maximé: rursus generalia minus certa documenta exhibere. Medullam igitur scientiarum, quâ artifex ab imperito distinguitur, in mediis propositionibus consistere, quas per singulas scientias tradidit et docuit experientia.”
Classification broadly enunciated, and strongly recommended — yet feebly applied — in this dialogue.