Namque canebat, uti magnum per inane coacta
  Semina terrarumque animaeque marisque fuissent
  Et liquidi simul ignis; ut his exordia primis
  Omnia et ipse tener mundi concreverit orbis;
  Tum durare solum et discludere Nerea ponto
  Coeperit, et rerum paulatim sumere formas;
  Iamque novum terrae stupeant lucescere solem. 
  Altius atque cadant summotis nubibus imbres;
  Incipiant silvae cum primum surgere, cumque
  Rara per ignaros errent animalia montis.

The myths that follow are meant to continue this list of subjects, only with somewhat less blunt obviousness.  They suggested to Varus the usual Epicurean theories of perception, imagination, passion, and mental aberrations, subjects that Siro must have discussed in some such way as Lucretius treated them in his third and fourth books of the De Rerum Natura.

It is, of course, not to be supposed that Siro had lectured upon mythology as such.  But the Epicurean teachers, despite their scorn for legends, employed them for pedagogical purposes in several ways.  Lucretius, for instance, uses them sometimes for their picturesqueness, as in the prooemium and again in the allegory of the seasons (V. 732).  He also employs them in a Euhemeristic fashion, explaining them as popular allegories of actual human experiences, citing the myths of Tantalus and Sisyphus, for example, as expressions of the ever-present dread of punishment for crimes.  Indeed Vergil himself in the Aetna—­if it be his—­somewhat naively introduced the battle of the giants for its picturesque interest.  It is only after he had enjoyed telling the story in full that he checked himself with the blunt remark: 

  (1. 74) Haec est mendosae vulgata licentia famae.

Lucretius is little less amusing in his rejection of the Cybele myth, after a lovely passage of forty lines (II, 600) devoted to it.

Vergil was, therefore, on familiar ground when he tried to remind his schoolmate of Siro’s philosophical themes by designating each of them by means of an appropriate myth.  Perhaps we, who unlike Varus have not heard the original lectures, may not be able in every case to discover the theme from the myth, but the poet has at least set us out on the right scent by making the first riddles very easy.  The lapides Pyrrhae (I. 41) refer of course to the creation of man; Saturnia regna is, in Epicurean lore, the primitive life of the early savages; furtum Promethei (I. 42) must refer to Epicurus’ explanation of how fire came from clashing trees and from lightning.  The story of Hylas (I. 43) probably reminded Varus of Siro’s lecture on images and reflection, Pasiphae (I. 46) of unruly passions, explained perhaps as in Lucretius’ fourth book, Atalanta (I. 61) of greed, and Phaeton of ambition.  As for Scylla, Vergil had himself in the Ciris (I. 69) mentioned, only to reject, the allegorical interpretation here presented, according to which she portrays: