Any of the passages which are not needed for the special practical purpose of the poem may be regarded as episodical, such, for instance, as that thoroughly Lucretian passage in Book I. in which the feelings of rooks are explained on purely physical principles, or that passage of Book IV. inspired by the teaching of an opposite school, in which the theory of a divine principle pervading the world--the same theory as that accepted as his own by Virgil in Aeneid VI.--is enunciated as a probable explanation of the higher instinct of the bees. And it is characteristic of the eclecticism of Virgil's mode of thought, and also of the lingering regret with which he regards the evanescent fancies of the old mythology, that he not only combines these tenets of the most materialistic and most spiritualistic philosophies in the same poem, but that the philosophic or theosophic solution of Book IV. 219, etc. comes shortly after a passage in which the same phenomenon is accounted for on the ground of the service rendered by bees in feeding the infant Jove in the cavern of Mount Dicte. Another passage of a scientific rather than a philosophic character is that at Book I. 233, etc., in which the five zones girding the heaven and the earth are described in language closely translated from Eratosthenes. Besides the scientific interest which this passage must have had to the poet's contemporaries, it serves to draw forth Virgil's antagonism to the religious unbelief of Lucretius, in the expression
and also to imply his dissent from the emphatic denial which Lucretius gives, at Book I. 1065, to the Stoical belief in the existence of the Antipodes:--
Illi cum videant solem, nos sidera noctis Cernere, et alternis nobiscum tempora caeli Dividere, et noctes parilis agitare diebus(366).
Another passage of a semi-philosophical character is that at Book III. 242-283, in which the Lucretian idea of the all-pervading influence of the physical emotion of love over all living things in sea, earth, and air,--an idea in which Lucretius was anticipated by Euripides(367) and by other earlier Greek poets,--appears in combination with the purely mythological conception of the direct personal agency of Venus, and with the legend of 'the mares of Glaucus of Potniae.'