Question as to education of the Nocturnal Council is answered in the Epinomis.
Such then is the answer given by the Epinomis, to the question left unanswered in the Leges. However unsatisfactory it may appear, to those who look for nothing but what is admirable in Plato — I believe it to represent the latest views of his old age, when dialectic had given place in his mind to the joint ascendancy of theological sentiment and Pythagorean arithmetic.[494]
[494] In connection with the treatise called Epinomis, the question arises, What were the modifications which Plato’s astronomical doctrines underwent during the latter years of his life? In what respect did they come to differ from what we read in the Platonic Timæus, where a geocentric system is proclaimed: whether we suppose (as Boeckh and others do) that the Earth is represented as stationary at the centre — or (as I suppose) that the Earth is represented as fastened to the centre of the kosmical axis, and revolving with it. The Epinomis delivers a geocentric system also.
Now it is upon this very point that Plato’s opinions are said to have changed towards the close of his life. He came to repent that he had assigned to the Earth the central place in the system; and to conceive that place as belonging properly to something else, some other better (or more powerful) body. This is a curious statement, made in two separate passages by Plutarch, and in one of the two passages with reference to Theophrastus as his witness (Plutarch, Vit. Numæ, c. 11; Platonic. Quæst. 8, p. 1006 C).
Boeckh (Untersuchungen über das Kosmische System des Platon, pp. 144-149) and Martin (Études sur le Timée, ii. 91) discredit the statement ascribed by Plutarch to Theophrastus. But I see no sufficient ground for such discredit. Sir George Lewis remarks very truly (Historical Survey of the Astronomy of the Ancients, p. 143):— “The testimony of Theophrastus, the disciple of Aristotle, and nearly his contemporary, has great weight on this point. The ground of the opinion alludes to the Pythagorean doctrine mentioned by Aristotle, that the centre is the most dignified place, and that the earth is not the first in dignity among the heavenly bodies. It has no reference to observed phenomena, and is not founded on inductive scientific arguments. … The doctrine as to the superior dignity of the central place, and of the impropriety of assigning the most dignified station to the earth, was of Pythagorean origin and was probably combined with the Philolaic cosmology.”
This remark of Sir George Lewis deserves attention, not merely from the proper value which he assigns to the testimony of Theophrastus, but because he confines himself to the exact matter which Theophrastus affirmed; viz., that Plato in his old age came to repent of his own cosmical views on one particular point and on one special ground. Theophrastus does not tell us what it was that Plato supposed to be in the centre, after he had become convinced that it was too dignified a place for the earth. Plato may have come to adopt the positive opinion of Philolaus (that of a central fire) as well as the negative opinion (that the Earth was not the central body). But we cannot affirm that he did adopt either this positive opinion or any other positive opinion upon that point. I take Theophrastus to have affirmed exactly what Plutarch makes him affirm, and no more: that Plato came to repent of having assigned to the earth the central place which did not befit it, and to account the centre the fit place “for some other body better than the Earth,” yet without defining what that other body was. If Theophrastus had named what the other body was, surely Plutarch would never have suppressed the specific designation to make room for the vague ἑτέρῳ τινὶ κρείττονι.
There is thus, in my judgment, ground for believing that Plato in his old age (after the publication of the Treatise De Legibus) came to distrust the geocentric dogma which he had previously supported; but we do not know whether he adopted any other dogma in place of it. The geocentric doctrine passed to the Epinomis as a continuation of the Treatise De Legibus. The phrase which Plutarch cites from Theophrastus deserves notice — Θεόφραστος δὲ καὶ προσιστορεῖ τῷ Πλάτωνι πρεσβυτέρῳ γενομένῳ μεταμελεῖν, ὡς οὐ προσήκουσαν ἀποδόντι τῇ γῇ τὴν μέσην χώραν τοῦ παντός. Plato repented. Whoever reads the Treatise De Legibus (especially Books vii. and x.) will see that Plato at that period of his life considered astronomical errors as not merely errors, but heresies offensive to the Gods; and that he denounced those who supported such errors as impious. If Plato came afterwards to alter his astronomical views, he would repent of his own previous views as of a heresy. He came to believe that he had rated the dignity of the Earth too high; and we can see how this change of view may have been occasioned. Earth was looked upon by him, as well as by many others, in two distinct points of view. 1. As a cosmical body, divine, and including τοὺς χθονίους θεούς. 2. As one of the four elements, along with water, air, and fire; in which sense it was strung together with λίθοι, and had degrading ideas associated with it (Plato, Apol. Sokr. p. 26 D). These two meanings, not merely distinct but even opposed to each other, occur in the very same sentence of De Legibus, x. p. 886 D. The elemental sense of Earth was brought prominently forward by those reasoners whom Plato refutes in Book x.: and the effect of such reasonings upon him was, that though he still regarded Earth as a Deity, he no longer continued to regard Earth as worthy of the cosmical post of honour. At that age, however, he might well consider himself excused from broaching any new positive theory.
Problem which the Nocturnal Council are required to solve, What is the common property of Prudence, Courage, Temperance, Justice, by reason of which each is called Virtue?
Assuming that the magistrates of the Nocturnal Council have gone through the course of education prescribed in the Epinomis, and have proved themselves unimpeachable on the score of orthodoxy — will they be able to solve the main problem which he has imposed upon them at the close of the Leges? There, as elsewhere, he proclaims a problem as indispensable to be solved, but does not himself furnish any solution. What is the common property, or point of similarity between Prudence, Courage, Temperance, Justice — by reason of which each is termed Virtue? What are the characteristic points of difference, by reason of which Virtue sometimes receives one of these names, sometimes another?
The only common property is that all of them are essential to the maintenance of society, and tend to promote human security and happiness.