Note 258 — Chapter XXXIX · LEGES AND EPINOMIS. (continued 2)

Plato, Legg. vii. pp. 819 D, 821 E.

This portion of the Leges is obscure, and would be hardly intelligible if it were not illustrated by a passage in the Timæus (p. 38). Even with such help it is difficult, and has been understood differently by different interpreters. Proklus (in Timæum, pp. 262-263) and Martin (Études sur le Timée, ii. note 36, p. 84) interpret it as alluding to the spiral line (ἕλικα) described by each planet (Sun and Moon are each counted as planets) round the Earth, arising from the combination of the force of the revolving sidereal sphere or Aplanês, carrying all the planets round along with it from East to West, with the counter-movement (contrary, but obliquely contrary) inherent in each planet. The spiral movement of each planet, resulting from combination of these two distinct forces, is a regular movement governed by law; though to an observer who does not understand the law, the movements appear irregular. Compare Derkyllides ap. Theon Smyrn. c. 41, f. 27, p. 330, ed. Martin.

The point here discussed forms one of the items of controversy between Gruppe and Boeckh, in the recent discussion about Plato’s astronomical views. Gruppe, Die Kosmischen Systeme der Griechen, pp. 157-168: Boeckh, Untersuchungen über das Kosmische System des Platon, pp. 45-57.

Gruppe has an ingenious argument to show that the novelty (παράδοξον) which Plato had in his mind, but was afraid to declare openly because of existing prejudices, was the heliocentric or Copernican system, which he believes to have been Plato’s discovery. Boeckh refutes Gruppe’s reasoning; and refutes it, in my judgment, completely. He sustains the interpretation given by Proklus and Martin.

Boeckh also illustrates (pp. 35-38-49-54), in a manner more satisfactory than Gruppe, the dicta of Plato about the comparative velocity of the Planets (Sun and Moon counted among them).

Plato declares the Moon to be the quickest mover among the planets, and Saturn to be the slowest. On the contrary Demokritus pronounced the Moon to be the slowest mover of all; slower than the Sun, because the Sun was farther from the Earth and nearer to the outermost or sidereal sphere. It was the rotation of this last-mentioned sphere (according to Demokritus) which carried round along with it the Sun, the Moon, and all the planets: the bodies near to it were more forcibly acted upon by its rotation, and carried round more rapidly, than the bodies distant from it — hence the Moon was the least rapid mover of all (Lucretius, v. 615-635. See Sir George Lewis’s Historical Survey of the Astronomy of the Ancients, ch. ii. pp. 139-140).

It appears to me probable that Plato, in the severe remarks which he makes on persons who falsely affirmed the quickest mover in the heavens to be the slowest, had in view these doctrines of Demokritus. Plato never once mentions Demokritus by name (see Mullach, Fragment. Demokrit. p. 25); but he is very sparing in mentioning by name any contemporaries. It illustrates the difference between the manner of Aristotle and Plato, that Aristotle frequently names Demokritus — seventy-eight times according to Mullach (p. 107) — even in the works which we possess.