Such is probably the case with the cosmos too, if it really is a living beingIn , 1115 B Strato’s denial of this is cited as an example of his opposition to Plato; and in , 1014 C - D Plutarch, speaking of the creation of the world by the Platonic demiurge, says τὸ κάλλιστον ἀπεργασάμενος καὶ τελειότατον ζῳον, thereby referring to such passages as , 30 B - D, 32 C - D, 68 E, 69 B - C. Still, Platonic though it is, this assumption is one which his Stoic adversaries would grant (cf. Diogenes Laertius, vii. 139 and 142-143 [= ii, frags. 634 and 633]); and Plutarch believes that in granting it they are committed to the implication that the moon despite its location can consist of earth.: in many places it has earth and in many fire and water and breath as the result not of forcible expulsioncf.Aristotle, , 277 B 1-2: ουδὲ βίᾳ (scil. φέρεται αὐτῦν τὸ μὲν ἄνω τὸ δὲ κάτω) ὥσοερ τινές φασι τῇ ἐκθλίξει, and Cherniss, , p. 191, n. 196. but of rational arrangement. After all, the eye has its present position in the body not because it was extruded thither as a result of its lightness, and the heart is in the chest not because its heaviness has caused it to slip and fall thither but because it was better that each of them should be so located. Let us not then believe with regard to the parts of the cosmos either that earth is situated here because its weight has caused it to subside or that the sun, as Metrodorus of ChiosFor this Atomist, who is not to be confused with the Epicurean, Metrodorus of Lampsacus, or with the Anaxagorean, cf. Diels-Kranz, ii, pp. 231-234; the present passage should be added to that collection, from which it is missing. According to , 889 B ( = Aëtius, ii. 15. 6 [, p. 345 A 7-12]) Metrodorus considered the sun to be farthest from the earth, the moon below it, and lower than the moon the planets and fixed stars. For the explanation of the suns position here ascribed to Metrodorus see note a supra and cf. Simplicius, De Caelo, p. 712. 27-29. once thought, was extruded into the upper region like an inflated skin by reason of its lightness or that the other stars got into their present positions because they tipped the balance, as it were, at different weights. On the contrary, the rational principle is in control; and that is why the stars revolve fixed like radiant eyes In , 98 B the phrase is quoted as Plato’s; it comes from , 45 B (τῶν δὲ ὀργάνων πρῶτον μὲν φωσφόρα συνευεκτήναντο ὄμματα, τοιᾷδε ἐνδήσαντες αἰτίᾳ), and Plutarch’s τῷ προσὠποῳ τοῦ παντὸς ἐνδεδεμένοι was suggested by this in conjunction with the preceding lines (45 a: . . . ὑποθέντες αὐτ aυτόσε τὸ πρόσωπον, ὄργανα ἐνέδησαν τούτῳ), though Plato is there speaking of the human face and eyes. in the countenance of the universe, the sun in the hearts capacity transmits and disperses out of himself heat and light as it were blood and breath, and earth and sea naturally serve the cosmos to the ends that bowels and bladder do an animal. The moon, situate between sun and earth as the liver or another of the soft viscerai.e. the spleen. For the purpose of liver and spleen cf. Aristotle, 670 A 20-29, 670 B 4-17, 673 B 25-28; and for the close connection of liver and spleen 669 B 15 670 A 2. is between heart and bowels, transmits hither the warmth from above and sends upwards the exhalations from our region, refining them in herself by a kind of concoction and purification.Eustathius, , 695. 12 ff. says that according to the Stoics the golden rope of , viii. 19 is ὁ ἥλιος εἰς ὃν κάτωθεν ὥσττερ εἰς καρδίαν ἀποχεῖται ἀναδιομένη ἡ τῶν ὑγρῶν ἀναθυμίασις. Starting from this K. Reinhardt (, pp. 332 ff.) argued that Posidonius was Plutarch’s source for the analogy between the parts of the cosmos and the organs of the body; but Reinhardt’s contention is refuted by R. M. Jones, xxvii (1932), pp. 121-128. Passages which equate sun and heart are fairly frequent, e.g. Theon of Smyrna, pp. 187. 13-188. 7 (Hiller); Proclus, , 171 C - D (ii, p. 104. 20-21 and 28-29, Diehl); Macrobius, i. 20. 6-7 (pp. 564-565, Eyssenhardt); Chalcidius, , § 100 (p. 170, Wrobel); Anon. Christ., , pp. 17.15-18.11 (Kroll-Viereck) with astrological ascriptions of different bodily organs to the seven planets. An entirely different analogy between the various human faculties and the seven planets is mentioned by Proclus, , 348 A - B (iii, p. 355. 7-18, Diehl), and Numenius in Macrobius, i. 12. 14-15 (p. 533, Eyssenhardt); and I know no parallel to Plutarch’s further analogy of earth and moon with bowels and liver or spleen. In the pseudo-Hippocratic the moon because of its central position in the cosmos appears to have been equated with the diaphragm (cf. Roscher, , p. 5. 45 ff., pp. 10-11, p. 123). In the section of Porphyry’s Introduction to Ptolemys Apotelesmatica published by F. Cumont in , i, pp. 155-156, the source of which Cumont contends must have been Antiochus of Athens, the moon is said to have the spleen as its special province, while the heart is assigned to the sun; but there the liver is the province of Jupiter. It is not clear to us whether her earthiness and solidity have any use suitable to other ends also. Nevertheless, in everything the better has control of the necessary.cf. Plato, Timaeus, 48 A: noῦ δὲ ἀνάγκης ἄρχοντος τῷ πείθειν αὐτὴν τῶν γιγομένων τὰ πλεῖστα ἐπι τὸ βέλτιστον ἄγρειν κτλ. For the term τὸ κατηναγκασμένον cf. ii, frag. 916. Well, what probability can we thus conceive in the statements of the Stoics? They say that the luminous and tenuous part of the ether by reason of its subtility became sky and the part which was condensed or compressed became stars, and that of these the most sluggish and turbid is the moon.= ii, frag. 668; cf. Cleomedes, ii. 3. 99 (pp. 178. 26-180. 8, Ziegler) and contrast ii. 4. 100 (p. 182. 8-10). On the Stoic ether cf. Diogenes Laertius, vii. 137 (= ii, frag. 580) and note g on 922 B supra. Yet all the same anyone can see that the moon has not been separated from the ether but that there is still a large amount of it about her in which she moves and much of it beneath her in which [they themselves assert that the bearded stars] and comets whirl. So it is not the inclinations consequent upon weight and lightness that have circumscribed the precinctsThe lexica give weigh balance as the meaning of σεσήλωται, but the logic of the passage here shows that the word must be connected with σηκός, not with σήκωμα (cf. Hesychius: ἀποσηκώσας and σάκωσε). Amyot’s situez et colloquez and Keplers quasi obvallata sunt render the sense correctly. of each of the bodies, but their arrangement is the result of a different principle.

With these remarks I was about to yield the floor to Lucius,It was ostensibly in order to give Lucius time to collect his thoughts that Lamprias began the remarks which he has just concluded after ten paragraphs (see 923 F supra). since the proofs of our position were next in order; but Aristotle smiled and said: The company is my witness that you have directed your entire refutation against those who suppose that the moon is for her part semi-igneous and yet assert of all bodies in common that of themselves they incline either upwards or downwards. Whether there is anyone, however, who saysThis is Aristotle, of course: , 269 A 2-18, 270 A 12-35; cf. [Aristotle], , 392 A 5-9 and , 887 D = Aëtius, ii. 7. 5 (, p. 336). that the stars move naturally in a circle and are of a substance far superior to the four substances hereI have added this word in the translation in order to make it clear that the four are the four sublunar substances, earth, water, air, and fire. did not even accidentally come to your notice, so that I at any rate have been spared trouble. And Lucius [broke in and] said: good friend, probably one would not for the moment quarrel with you and your friends, despite the countless difficulties involved, when you ascribe to the other stars and the whole heaven a nature pure and undefiled and free from qualitative change and moving in a circle whereby [it is possible to have the nature] of endless revolution too; but let this doctrine descend and touch the moon, and in her it no longer preserves the impassivity and beauty of that body. Not to mention her other irregularities and divergencies, this very face which she displays is the result of some alteration of her substance or of the admixture somehow of another substance.cf. Aëtius, ii. 30. 6 (, p. 362 B 1-4): Ἀριστοτέλης μὴ εἶναι αὐτῆs (scil. σελήνης) ἀκήρατον τὸ σύγκριμα διὰ τὰ πρόσγεια ἀερώματα τoῦ αἰθέρος, ὃν προσαγορεύει σῶμα πέμπτον. In fact in 761 B 22 Aristotle does say that the moon shares in the fourth body, i.e. fire. That which is subjected to mixture, however, is the subject of some affection too, for it loses its purity, since it is perforce infected by what is inferior to it. The moon’s sluggishness and slackness of speed and the feebleness and faintness of her heat [which], in the words of Ion, ripes not the grape to duskiness,At 658 C Plutarch quotes the whole line, Ion, frag. 57 (Nauck²). to what shall we ascribe them except to her weakness and alteration, [if] an eternal and celestialFor the epithet ὀλύμπιος used of the moon cf. 935 C s.v. and , 416 E: οἱ δ’ ὀλυμπίαν γῆν (scil. σελήνην) προσεῖπον, and for the meaning attached to it cf. the etymology in the pseudo-Plutarchian , B, 95 [vii, p. 380. 17-20, Bernardakis]; Pseudo-Plutarch in Stobaeus, , i. 22 (i, p. 198. 10 ff., Wachsmuth); [Aristotle], , 400 A 6-9; Eustathius, , 38. 38. body can have any part in [alteration]? The fact is in brief, my dear Aristotle, that regarded as earth the moon has the aspect of a very beautiful, august, and elegant object; but as a star or luminary or a divine and heavenly body she is, I am afraid, misshapen, ugly, and a disgrace to the noble title, if it is true that of all the host in heaven she alone goes about in need of alien light,At 1116 A Plutarch quotes Parmenides as having called the moon άλλότριον φῶς (= Parmenides, frag. B 14 [i, p. 243. 19, Diels-Kranz]); cf. Empedocles, frag. B 45 (i, p. 331. 2 [Diels-Kranz]). as Parmenides says Fixing her glance forever on the sun.= Parmenides, frag. B 15 (i, p. 244. 3 [Diels-Kranz]), quoted also at 282 B. Our comrade in his discourseSee note a on p. 48 supra. won approval by his demonstration of this very proposition of Anaxagorass that the sun imparts to the moon her brilliance = Anaxagoras, frag. B 18 (ii, p. 41. 5-7 [Diels-Kranz]).; for my part, I shall not speak about these matters that I learned from you or in your company but shall gladly proceed to what remains. Well then, it is plausible that the moon is illuminated not by the suns irradiating and shining through her in the manner of glasscf. Aëtius, ii. 25. 11 (, p. 356 B 21) = Ion of Chios, frag. A 7 (i, p. 378. 33-34 [Diels-Kranz]). or iceSee note c on 922 C supra. nor again as the result of some sort of concentration of brilliance or aggregation of rays, the light increasing as in the case of torches.cf., 891 F = Aëtius, ii. 29. 4 (, p. 360 A 3-8 and b 5-11). Were that true, we should see the moon at the full on the first of the month no less than in the middle of the month, if she does not conceal and obstruct the sun but because of her subtility lets his light through or as a result of combining with it flashes forth and joins in kindling the light in herself.The latter was the theory of Posidonius as Plutarch indicates in 929 D s.v.; cf. Cleomedes, ii. 4. 101 (pp. 182. 20-184. 3 [Ziegler]) and ii. 4. 104-105 (pp. 188. 5-190. 16). Certainly her deviations or aversionsi.e. the various deflections of the moon in latitude and the varying portion of the lunar hemisphere turned away from the sun as the moon revolves in her orbit. For these two variations in the explanation of the lunar phases cf. Cleomedes, ii. 4. 100 (pp. 180. 26-182. 7 [Ziegler]), and Geminus, ix. 5-12 (p. 126. 5 ff. [Manitius]). cannot be alleged as the cause of her invisibility when she is in conjunction, as they are when she is at the half and gibbous or crescent; then, rather, standing in a straight line with her illuminant, says Democritus, she sustains and receives the sun, = Democritus, frag. A 89 a (ii, p. 105. 32-34 [DielsKranz]). For the meaning of κατὰ στάθμην cf. , 883 a, 884 C. The words ὑπολαμβάνει καὶ δέχεται have a sexual meaning here; cf. 944 E s.v., , 372 D, , 770 A, and Roscher, über Selene und Verwandtes, pp. 76 ff. so that it would be reasonable for her to be visible and to let him shine through. Far from doing this, however, she is at that time invisible herself and often has concealed and obliterated him. His beams she put to flight, as Empedocles says, From heaven above as far as to the earth, Whereof such breadth as had the bright-eyed moon She cast in shade,= Empedocles, frag. B 42 (i, p. 330. 11-13 [Diels-Kranz]). just as if the light had fallen into night and darkness and not upon an other star. As for the explanation of Posidonius that the profundity of the moon prevents the light of the sun from passing through her to us,See note h on 929 C supra. In Cleomedes, ii. 4. 105 (p. 190. 4-16 [Ziegler]) the refutation given by Plutarch here is answered or anticipated by the statement that the air does not have βάθος as the moon does, and from what follows it appears that by the βάθος of the moon Posidonius must have meant not mere spatial depth but a certain density as well. this is obviously refuted by the fact that the air, though it is boundless and has many times the profundity of the moon, is in its entirety illuminated and filled with sunshine by the rays. There remains then the theory of Empedocles that the moonlight which we see comes from the moons reflection of the sun. That is why there, is neither warmtha At 937 B s.v. and , 404 D it is said that in being reflected from the moon the sun’s rays lose their heat entirely (cf. Macrobius, i. 19. 12-13 [p. 560. 30 ff., Eyssenhardt]). Just above, however, at 929 A Plutarch ascribed to the moonlight a feeble heat, and so he does in 918 A (cf. Aristotle, 680 A 3334; [Aristotle], , 942 A 24-26; Theophrastus, iv. 14. 3). Kepler (, note 200) asserts that he had felt the heat from the rays of the full moon concentrated in a concave parabolic mirror; but the first real evidence of the moon’s heat was obtained by Melloni in 1846 by means of the newly invented thermopile. cf. R. Pixis, , p. 135; S. Günther, , p. 82, n. 3; Nasmyth-Carpenter, (London, 1885), p. 184. nor brilliance in it when it reaches us, as we should expect there to be if there had been a kindling or mixture of [the] lights [of sun and moon].I have added the words sun and moon in the translation to make explicit the meaning of [τῶν] φώτων. For the theory referred to see note h on 929 C supra. To the contrary, just as voices when they are reflected produce an echo which is fainter than the original sound and the impact of missiles after a ricochet is weaker, Thus, having struck the moon’s broad disk, the ray= Empedocles, frag. B 43 (i, p. 330. 20 [Diels-Kranz]). comes to us in a refluence weak and faint because the deflection slackens its force.

Sulla then broke in and said: No doubt this position has its plausible aspects; but what tells most strongly on the other side, did our comradeSee 929 B and note a on p. 48 supra. explain that away or did he fail to notice it? What’s that? said Lucius, or do you mean the difficulty with respect to the half-moon? Exactly, said Sulla, for there is some reason in the contention that, since all reflection occurs at equal angles,This expression is intended to have the same sense as πρὸς ἴσας γίγνεσθαι γωνίας ἀνάκλασιν πᾶσαν (930 A s.v.), and both of them mean (pace Raingeard, p. 100, and Kepler in note 28 to his translation) the angle of reflection is always equal to the angle of incidence. cf. [Euclid], aà (= Euclid, , vii, p. 286. 21-22 [Heiberg]) with Olympiodorus, p. 212. 7 = Hero Alexandrinus, , ii. 1, p. 368. 5 (Nix-Schmidt) and [Ptolemy], , ii = Hero Alexandrinus, , ii. 1, p. 320. 12-13 (Nix-Schmidt); and contrast the more precise formulation of Philoponus, p. 27. 34-35. whenever the moon at the half is in mid-heaven the light cannot move earthwards from her but must glance off beyond the earth. The ray that then touches the moon comes from the sun on the horizonKepler in note 19 to his translation points out that this is true only if μεσουρανῇ is in mid-heaven refers not to the meridian but to the great circle at right-angles to the ecliptic. and therefore, being reflected at equal angles, would be produced to the point on the opposite horizon and would not shed its light upon us, or else there would be great distortion and aberration of the angle, which is impossible. Cleomedes, ii. 4. 103 (p. 186. 7-14 [Ziegler]) introduces as σχεδὸν γνώριμον his summary of this argument against the theory that moonlight is merely reflected sunlight. Yes, by Heaven, said Lucius, there was talk of this too; and, looking at Menelaus the mathematician as he spoke, he said: In your presence, my dear Menelaus, I am ashamed to confute a mathematical proposition, the foundation, as it were, on which rests the subject of catoptrics. Yet it must be said that the proposition, all reflection occurs at equal angles, See note e on 929 F supra. is neither self-evident nor an admitted fact.It has been suggested that οὔθ’ ὁμολογούμενον is a direct denial of ὡμολογηένον ἐστι παρὰ πᾶσιν at the beginning of Hero’s demonstration (Schmidt in Hero Alexandrinus, [ed. Nix-Schmidt], ii. 1, p. 314. However that may be, the law is assumed in Proposition XIX of Euclid’s , where it is said to have been stated in the (Euclid, , vii, p. 30. 1-3 [Heiberg]); and a demonstration of it is ascribed to Archimedes (, 7 = Euclid, , vii, p. 348. 17-22 [Heiberg]; cf. Lejeune, , xxxviii [1947], pp. 51 ff.). It is assumed by Aristotle in , iii. 3-5 and possibly also by Plato (cf. Cornford, Platos , pp. 154 f. on , 46 B); cf. also Lucretius, iv. 322-323 and [Aristotle], , 901 B 21-22 and 915 B 30-35. Proposition XIX of Euclids , referred to above, is supposed to be part of the Dioptrics of Euclid which Plutarch cites at , 1093 E (cf. Schmidt, Op. cit. p. 304). It is refuted in the case of convexi.e. cylindrical, not spherical, convex mirrors; cf. xlvi (1951), pp. 142-143 for the construction and meaning of this sentence. mirrors when the point of incidence of the visual ray produces images that are magnified in one respect; and it is refuted by folding mirrors,For such mirrors cf. [Ptolemy], , xii = Hero Alexandrinus, , ii. 1, p. 342. 7 ff. either plane of which, when they have been inclined to each other and have formed an inner angle, exhibits a double image, so that four likenesses of a single object are produced, two reversed on the outer surfaces and two dim ones not reversed in the depth of the mirrors. The reason for the production of these images Plato explains,Plutarch means , 46 B - C, where Plato, however, describes a concave, cylindrical mirror, not a folding plane mirror. Plutarch apparently mistook the words ἔνθεν καὶ ἔνθεν ὕξη λαβoῦσα, by which Plato describes the horizontal curvature of the mirror, to mean that the two planes of a folding mirror were raised to form an angle at the hinge which joined them. for he has said that when the mirror is elevated on both sides the visual rays interchange their reflection because they shift from one side to the other. So, if of the visual rays (some) revert straight to us (from the plane surfaces) while others glance off to the opposite sides of the mirrors and thence return to us again, it is not possible that all reflections occur at equal angles.See note e on 929 F supra. Consequently (some people) take direct issue (with the mathematicians) and maintain that they confute the equality of the angles of incidence and reflection by the very streams of light that flow from the moon upon the earth, for they deem this fact to be much more credible than that theory. Nevertheless, suppose that thisi.e. the theory that the angle of reflection is always equal to the angle of incidence. must be conceded as a favour to geometry, the dearly beloveds3 In the first place, it is likely to occur only in mirrors that have been polished to exact smoothness; but the moon is very uneven and rugged, with the result that the rays from a large body striking against considerable heights which receive reflections and diffusions of light from one another are multifariously reflected and intertwined and the refulgence itself combines with itself, coming to us, as it were, from many mirrors. In the second place, even if we assume that the reflections on the surface of the moon occur at equal angles, it is not impossible that the rays as they travel through such a great interval get fractured and deflectedWith these words Plutarch means to refer to the effects of refraction; cf. , 894 C = Aëtius, iii. 5. 5 (, p. 372. 21-26); Cleomedes, ii. 6. 124-125 (p. 224. 8-28 [Ziegler]); Alexander, p. 143. 7-10. so as to be blurred and to bend their light. Some people even give a geometrical demonstration that the moon sheds many of her beams upon the earth along a line extended from the surface that is bent away from uscf. the argument given by Cleomedes, ii. 4. 103 (pp. 186. 14-188.7 [Ziegler]) and especially: ὅτι δ᾽ ἀπὸ παντὸς τοῦ κύκλου αὐτῆς φωτίζεται ἡ γῆ, γνώριμον. εὐθέως γὰρ ἅμα τῷ τὴν πρώτην ἴτυν ἀνασχεῖν ἐκ τοῦ ὁρίζοντος φωτίζει τὴν γῆν, τούτων τῶν μερῶν αὐτῆς περικλινῶν ὄντων καὶ πρός τὸν οὐρανόν, ἀλλ᾽οὐχί, μὰ Δία, πρὸς τὴν γῆν ὁρώντων For ἡ ἐκκεκλιμένη cf. Hippocrates, 38 (iv, p. 168. 18 [Littrè]).; but I could not construct a geometrical diagram while talking, and talking to many people too.

Speaking generally, he said, I marvel that they adduce against us the moon’s shining upon the earth at the half and at the gibbous and the crescent phases too.i.e. the moon at the half, gibbous, and crescent phases presents such a great difficulty for the Stoics themselves that it is strange for them to adduce these phenomena as refutation of the theory that the moon shines by reflected light. Wyttenbach’s conjecture, ἐκπίπτουσαν for ἐμπίπτουσαν, approved by Purser and apparently adopted by Prickard in his translation of 1918, betrays a misapprehension of the meaning of the text. After all, if the mass of the moon that is illuminated by the sun were ethereal or fiery, the sun would not leave herFor ἀπέλειπεν cf. 931 C s.v.. The dative with the verb is unobjectionable, cf. e.g. [] 178 D, 195 F. a hemisphere that to our perception is ever in shadow and unilluminated; on the contrary, if as he revolves he grazed her ever so slightly, she should be saturated in her entirety and altered through and through by the light proceeding easily in all directions. Since wine that just touches water at its surfaceFor κατὰ πέρας cf. , 1080 E ( = ii, frag, 487): ψαύειν κατὰ πέρας τὰ σώματα λέγουσι and ii, frag. 433 cited in note d on 930 F s.v.. The emendations of Emperius and Papabasileios are consequently ill-advised. or a drop of blood fallen into liquid at the moment [of contact] stains all the liquid red,cf., 1078 D - E ( = ii, frag. 480) and ii, frags. 473, 477, 479. and since they say that the air itself is filled with sunshine not by having any effluences or rays commingled with it but by an alteration and change that results from impact or contact of the light,cf. ii, frag. 433 (Galen, iv, vol. xvii, B, p. 161 [Kühn], especially: τοῖς ἄνω πέρασιν αὐτοῦ (scil. τοῦ ἀέρος) προσπιπτούσης τῆς ἡλιακῆς αὐγῆς ὅλος ἀλλοιοῦταί τε καὶ μεταβάλλεται συνεχὴς ὢν ἑαυτῷ). cf. also note a on 922 E supra. how do they imagine that a star can come in contact with a star or light with light and instead of blending and producing a thorough mixture and change merely illuminate those portions of the surface which it touches?cf. Cleomedes, ii. 4. 101 (p. 182. 20 ff. [Ziegler]) for the doctrine of Posidonius, which Plutarch here turns against him and the Stoics generally: τρίτη ἐστὶν αἵρεσις ἡ λέγουσα κιρνᾶσθαι αὐτῆς (scil. τῆς σελήνης) τὸ φῶς ἔκ τε τοῦ οἰκείου καὶ τοῦ ἡλιακοῦ φωτὸς καὶ τοιοῦτον γίνεσθαι οὐκ ἀπαθοῦς μενούσης αὐτῆς ἀλλ᾽ ἀλλοιουμένης ὑπὸ τοῦ ἡλιακοῦ φωτὸς καὶ κατὰ τοιαύτην τὴν κρᾶσιν ἴδιον ἰσχούσης τὸ φῶς cf. ibid. 104 (p. 188. 4-7). In fact, the circle which the sun in its revolution describes and causes to turn about the moon now coinciding with the circle that divides her visible and invisible parts and now standing at right angles to it so as to intersect it and be intersected by it, by different inclinations and relations of the bright part to the dark producing in her the gibbous and crescent phases,cf. Cleomedes, ii. 5. 109-111 (pp. 196. 28-200. 23 [Ziegler]). conclusively demonstrates that her illumination is the result not of combination but of contact, not of a concentration of light within her but of light shining upon her from without. In that she is not only illuminated herself, however, but also transmits to us the semblance of her illumination, she gives us all the more confidence in our theory of her substance. There are no reflections from anything rarefied or tenuous in texture, and it is not easy even to imagine light rebounding from light or fire from fire; but whatever is to cause a repercussion or a reflection must be compact and solid,Here ἐμβριθές is used as the opposite of λεπτομερές (cf. Liddell and Scott, s.v. ἐμβρίθεια ii) as πυκνόν is of ἀραιόν. in order that it may stop a blow and repel it.cf. Cleomedes, ii. 4. 101-102 (p. 184. 9-18 [Ziegler]). Cleomedes, assuming that the moon is μανόν, uses this as an argument against reflection; Plutarch, having established the necessity of reflection, uses the argument to support the contention that the moon is earthy. At any rate, the same sunlight that the air lets pass without impediment or resistance is widely reflected and diffused from wood and stone and clothing exposed to its rays. The earth too we see illuminated by the sun in this fashion. It does not let the light penetrate its depths as water does or pervade it through and through as air does; but such as is the circle of the sun that moves around the moon and so great as is the part of her that it intercepts, just such a circle in turn moves around the earth, always illuminating just so much and leaving another part unilluminated,cf. Cleomedes, ii. 5. 108 (p. 194. 20 ff. [Ziegler]). for the illuminated portion of either body appears to be slightly greater than a hemisphere.Cleomedes, ii. 5. 109 (p. 198. 6-9 [Ziegler]). Give me leave then to put it in geometrical fashion in terms of a proportion. Given three things approached by the light from the sun: earth, moon, air; if we see that the moon is illuminated not as the air is rather than as the earth, the things upon which the same agent produces the same effects must be of a similar nature. I have tried to preserve the contorted form in which Plutarch expresses the point that the moon, since it is affected by sunlight as the earth is and not as air is, must have the consistency of earth and not of air.