Dante has reached the first sphere of the Ptolemaic system.

 

32. dense and smoothly polished as a diamond: Dante finds the surface of the Moon to be diamond-smooth and highly polished (the telescope that was to reveal the jagged surface had not yet been invented ).

 

35. the eternal pearl: The Moon.

 

37-42. THE UNITY OF GOD AND MAN. Dante is dealing here in the mysteries of faith. On Earth two bodies, being conceived as solids, cannot occupy the same space (“one dimension cannot bear another”). Yet, as light is received by water with no change in its self-unity, so Dante enters into the substance of the Moon, and this miraculous unity with which he enters the Moon-substance without disrupting it, sends his mind soaring to the mystery of the incarnation of Cod, and to the ultimate reception of the good man into the ineffable Logos. that Essence: Christ as the Man-God.

 

44. not told by reason: Reason is only the handmaiden of faith. With his final purification in the Earthly Paradise, Dante passed beyond reason to the greater way of knowing. Virgil’s last words to Dante were: “Lord of yourself I crown and miter you.” With his subsequent purification Dante achieves the state in which every effort of the will and of the intellect cease. Yet the understanding grows, for now the soul perceives as self-evident what had seemed incomprehensible to mere reason.

 

49-51. dark traces ... Cain? In Dante’s Italy what we call the Man in the Moon was fabled to be Cain with a Bush of Thorns. Recall that Dante has just described the lunar surface as being diamond-smooth and polished: such a surface would not show dark traces.

 

52-57. Sense: No wonder men fable falsely when they have no sensory evidence on which to base their reasoning. Even in matters about which firm sensory evidence is available to them they do not always reason correctly.

 

64-66. The eighth sphere: The Sphere of the Fixed Stars. lamps: Stars. qualities and quantities: Coloration and intensity. The phrasing of Beatrice’s disquisition is characteristically Scholastic: one can only repeat the admonition of the first six lines of the present Canto and hope the willing reader will accept the invitation of lines 10-18.

 

68. power: The influence of the stars upon the earth and upon the lives of men.

 

71. formal principle: Scholastic teaching distinguishes two principles in all bodies: the material, which is to say, the first matter, which is the same in all; and the formal, which is to say the substantial form that produces the various species and innate abilities of living forms. The formal principle is active; the material principle, passive. Dante’s reasoning is false in that it would reduce all to a single principle.

 

73 ff. BEATRICE’S EXPLANATION OF THE MARKINGS OF THE MOON. In il Convivio, II, 14, Dante had attributed these traces to differences in the density of the lunar matter, whereby the body reflected the light unequally. In this he followed Avicenna. (The reference to Avicenna in line 91 is not explicitly in the original text, but it is clearly implied.) Now, with Beatrice as his revelation, he refutes his earlier belief, having her first show that such a belief leads to impossible conclusions, and then having her assign the true cause to the special power diffused by the Primum Mobile. That power, though itself indivisible, dispenses itself with varying intensity according to the different bodies it permeates—as the soul, for example, permeates some parts of the body more intensely than it does others.

Beatrice’s argument is a curious one, Scholastic, pragmatic, and mystical by turn.