Stands, staying on his back the prop of earth And sky no tender burden to embrace.11Or, while under the moon there stretches air unsubstantial and incapable of supporting a solid mass, the earth, as Pindar says, is encompassed by steel-shod pillars12; and therefore Pharnaces is himself without any fear that the earth may fall but is sorry for the Ethiopians or Taprobanians,13 who are situated under the circuit of the moon, lest such a great weight fall upon them. Yet the moon is saved from falling by its very motion and the rapidity of its revolution, just as missiles placed in slings are kept from falling by being whirled around in a circle.14 For each thing is governed by its natural motion unless it be diverted by something else. That is why the moon is not governed by its weight: the weight has its influence frustrated by the rotatory motion. Nay, there would be more reason perhaps to wonder if she were absolutely unmoved and stationary like the earth. As it is, while <the> moon has good cause for not moving in this direction, the influence of weight alone might reasonably move the earth, since it has no part in any other motion; and the earth is heavier than the moon not merely in proportion to its greater size but still more, inasmuch as the moon has, of course, become light through the action of heat and fire.15 In short, your own statements seem to make the moon, if it is fire, stand in greater need of earth, that is of matter to serve it as a foundation, as something to which to adhere, as something to lend it coherence, and as something that can be ignited by it, for it is impossible to imagine fire being maintained without fuel,16 but you people say that earth does abide without root or foundation.’ 17 ‘Certainly it does,’ said Pharnaces, ‘in occupying the proper and natural place that belongs to it, the middle, for this is the place about which all weights in their natural inclination press against one another and towards which they move and converge from every direction, whereas all the upper space, even if it receive something earthy which has been forcibly hurled up into it, straightway extrudes it into our region or rather lets it go where its proper inclination causes it naturally to descend.’ 18
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1 The word τὸ περίακτον occurs in Comp. Lys. Sulla, iii, 476 E, where it seems to mean ‘the old saw,’ though it may refer to a proverbial state of ‘inside out and wrong side to.’ In De Gloria Atheniensium, 348 E Plutarch mentions μηχανὰς ἀπὸ σκηνῆς περιάκτους, but that rather tells against taking τὸ περίακτον as the name of this stage-machine. He uses περιαγωγή in De Genio Socratis, 588 D in the sense of ‘distraction’ and in Praecepta Gerendae Reipublicae, 819 A in the sense of ‘a trick of diversion,’ a sense which certainly suits τὸ περίακτον in the present context. The complaint of Pharnaces is frequently made by the interlocutors of Socrates; cf. Xenophon, Memorabilia, iv, 4. 9; Plato, Republic, 336 C; Aristotle, Soph. Elench. 183 B 6-8.
2 = S. V. F. i, p. 112, frag. 500; the title, ‘Against Aristarchus,’ appears in the list of Cleanthes writings given by Diogenes Laertius, vii. 174. For the theory of Aristarchus cf. Plutarch, Plat. Quaest. 1006 c; De Placitis 891 A = Aëtius, ii. 24. 8 (Dox. Graeci, p. 355); Archimedes, Arenarius, i. 1.4-7 (Opera Omnia, ii, p. 218 Heiberg); Sextus Empiricus, Adv. Math. x. 174; T. L. Heath, Aristarchus of Samos, pp. 301 ff.
3 i.e. we Academics, the party which did in fact maintain that the moon is an earthy body.
4 i.e. you Stoics; cf. Achilles, Isagogê, 4 = S. V. F. ii, frag. 555, p. 175. 36 ff.
5 This would not have been admitted by most of the Stoics, who thought that the moon is larger than the earth; but in this Posidonius and possibly others disagreed with the earlier members of the school; cf. Aëtius, ii. 26. 1 (Dox. Graeci, p. 357 and p. 68, n. 1), and M. Adler, Diss. Phil. Vind. x (1910), p. 155.
6 Cf. Cleomedes, ii. 1, § 80 (p. 146. 18 ff. Ziegler); Simplicius, De Caelo, p. 471. 6-11.
7 Cf. Cleomedes, ii. 2. §§ 93-94 (p. 170. 11 ff. Ziegler); Theon of Smyrna, p. 197. 1 ff. (Hiller); Pliny, Nat. Hist. ii. 11 (8), 51.
8 Cf. De Defectu Oraculorum, 410 D. Homer uses the phrase θοὴ νύξ frequently (e.g. Iliad, x. 394 [cf. Leaf's note ad loc.], Odyssey, xii. 284). Another θοός, supposedly meaning ‘pointed,’ ‘sharp’ and cognate with ἐθόωσα in Odyssey, ix. 327, is used of certain islands in Odyssey, xv. 299 (cf. Strabo, viii. 350-351; Pseudo-Plutarch, De Vita et Poesi Homeri, B, 21 [vii, p. 347. 19 ff. Bernardakis]). The latter passage so understood was used to support the hypothesis that θοὴ νύξ referred to the ‘sharpness’ of the earth's shadow: cf. Heracliti Quaestiones Homericae, §§ 45-46 (p. 67. 13 ff. Oelmann). Eustathius (Comment. ad Iliadem, 814. 15 ff.) mentions besides this another astronomical interpretation of the phrase by Crates of Mallos.
10 Cf. De An. Proc. in Timaeo, 1028 D where Plutarch ascribes to geometers the approximate calculation of three to one as the ratio of the earth's diameter to that of the moon and of twelve to one as the ratio of the sun's diameter to that of the earth, figures which agree roughly with those of Hipparchus (t : 1 : s = 1 . 1/3 . 12 1/3; cf. Heath, Aristarchus of Samos, pp. 342 and 350 after Hultsch). Hipparchus, however, considered the breadth of the shadow at the moon's mean distance from the earth in eclipses to be lunar diameters (Ptolemy, Syntaxis, iv. 9 [i, p. 327. 1-4 Heiberg]), while Aristarchus, whose calculations of the moon's diameter Plutarch quotes at 932 B infra, declared the shadow to be 2 lunar diameters in breadth (cf. Aristarchus, Hypothesis 5 [Heath, op. cit. p. 352. 13]; Pappus, Collectionis Quae Supersunt, ii, p. 554. 17-18 and p. 556. 14-17 [Hultsch]), the figure given by Cleomedes as well (pp. 146. 18-19 and 178. 8-13 [Ziegler]; cf. Geminus, Elementa, ed. Manitius, p. 272). Plutarch may here simply have assumed that the ratio of the lunar diameter to the breadth of the shadow would be the same as the Hipparchean ratio of the lunar diameter to the diameter of the earth; but he may also have erroneously supposed that the time taken by the moon to enter the shadow, the time of complete obscuration, and the time taken to leave the shadow equal three diameters instead of two (cf. Cleomedes, p. 146. 21-25 [Ziegler] and M. Adler, Diss. Phil. Vind. x , p. 156, n. 2).
11 Aeschylus, Prometheus Vinct. 351-352 (Smyth).
12 Pindar, frag. 88 (Bergk) = 79 (Bowra).
13 i.e. the Sinhalese; cf. Strabo, ii. 1. 14, chap. 72 and xv. 1. 14, chap. 690; Pliny, Nat. Hist. vi. 22 (24).
14 Cf. Aristotle, De Caelo, 284 A 24-26 and 295 A 16-21 (on Empedocles [Cherniss, Aristotle's Criticism of Presocratic Philosophy, p. 204, n. 234]). Plutarch himself in Lysander, xii. 3-4 (439 D) ascribes to Anaxagoras the notion that the heavenly bodies are kept from falling by the speed of their circular motion.
15 Here Lucius assumes the Stoic theory of the composition of the moon in order to rebut the Stoic objections.
16 Cf. Seneca, Nat. Quaest. vii. 1. 7: ‘ . . . magni fuere viri, qui sidera crediderunt ex duro concreta et ignem alienum pascentia. ‘nam per se,’ inquiunt, ‘flamma diffugeret, nisi aliquid haberet, quod teneret et a quo teneretur, conglobatamque nec stabili inditam corpori, profecto iam mundus turbine suo dissipasset.’ ’
17 Cf. Aristotle's remark (Meteorology, 353 A 34 - B 5) about the ancient θεολόγοι who assumed ῥίζαι γῆς καὶ θαλάττης and see Hesiod, Theogony, 728; Aeschylus, Prometheus Vinct. 1046-1047; and the ‘Orphic’ lines quoted by Proclus, In Timaeum, 211 C (ii, p. 231. 27-28 [Diehl]) = Kern, Orphicorum Fragmenta, 168. 29-30 (p. 202). The phrase ῥίζα καὶ βάσις is applied to the earth itself in a different sense by ‘Timaeus Locrus’ (97 E). For the ascription to Xenophanes of the notion that the earth ἐπ᾽ ἄπειρον ἐρρίζωται cf. Xenophanes, frag. A 47 (i, pp. 125-126 [Diels-Kranz]).
18 = S. V. F. ii, p. 195, frag. 646. This is the doctrine of proper place and natural motion, originally Aristotelian and ascribed to Aristotle in De Defectu Oraculorum, 424 B but adopted also by the Stoics (cf S. V. F. ii, p. 162. 14-19; p. 169. 8-11; p. 175. 16-35; p. 178. 12-15); it should not be confused, however, as Raingeard confuses it, with the Stoic doctrine that the universe itself is in the middle of the void (De Defectu Oraculorum, 425 D - E, De Stoicorum Repugnantiis, 1054 C - D).