Commentary Par VIII 3

Two words in this verse may benefit from closer attention. The verb raggiare is here used in the imperfect subjunctive, thus connoting a certain dubiety about the pagan opinion that the planet Venus was responsible for errors of erotic adventure. Cf. Conv.II.vi.9: '...the rays of each heaven are the paths along which their virtue descends [directly from the planet itself] upon these things here below' (tr. R. Lansing). Dante is speaking of Venus there, as he is here. For awareness of this connection, see Poletto (DDP Poletto.Par.VIII.1-12). It seems likely that, once again, Dante is undermining an opinion put forward in Convivio; his current opinion is that the angels who govern this sphere (and not the pagan amorous divinities) 'ray down' love into human fetuses.

The concept epicycle (epiciclo), another example of hapax legomenon, was the invention of ancient astronomers because their calculations of planetary movement, based on the belief that the earth was the center of the universe, around which the planets revolved, needed regularizing. And thus all the planets except the Sun supposedly had epicyclical movement. Here is Tozer on the nature of that motion (DDP Tozer.Par.VIII.1-3): 'The term "epicycle" means a circle, the centre of which is carried round upon another circle; cp. Convivio [Conv.II.iii.16-17]. To account for the apparent irregularities in the orbits of the heavenly bodies which resulted from the view that they revolved round the earth, which was stationary, Ptolemy suggested that each planet moved in such a circle of its own in addition to the revolution of the sphere to which it belonged. In the case of Venus this is called the third epicycle, because the sphere of Venus is the third in order in the heavens.'

And see Carroll (DDP Carroll.Par.VIII.1-21): 'Translating all this into its spiritual equivalent, the meaning appears to be: as Venus had one movement round the earth and another round the Sun, so these souls had two movements of the heart, cyclic and epicyclic, one round some earthly centre, the other round God, of whom the Sun is the natural symbol.'