(6.) The abstract properties of the atoms, discussed in the first two books, so far from being arbitrary assumptions, without any relation to actual existence, are thus found to be the conditions which explain the order, life, immensity, individuality, and subtlety manifested in the universe. These conceptions, which bridge the chasm between the particles of lifeless matter and the living world, unite in the more general conception of Nature. What then is involved in this conception--the dominant conception of the poem in its philosophical as well as its imaginative aspects? Something more than the subsidiary conceptions mentioned above. There is, in the first place, all that is involved in the unity of an organic whole. But to this whole the imagination of the poet seems, in some passages, to attach attributes scarcely reconcileable with the mechanical principles of his philosophy. In emancipating himself from the religious traditions of antiquity, Lucretius did not altogether escape from the power of an idea, so deeply rooted in the thought of past ages, as to seem to be an integral element of human consciousness. It is against the limitations which the ancient mythology imposed on the idea of Divine agency, rather than against the idea itself as it is understood in modern times, that his philosophy protests. To Nature his imagination attributes not only life, but creative and regulative power. There would be more truth in calling this conception pantheistic than atheistic. But the sense of will, freedom, individual life, is so strong in Lucretius, that we think of the 'natura daedala rerum' rather as a personal power, with attributes in some respects analogous to those of man, than as a being in whose existence all other life is merged. Though this figurative attribution of personal qualities to great natural forces cannot be pressed as evidence of philosophical belief, yet as it shows, on the one hand, an unconscious survival of the state of mind which gave birth to mythology, so it seems to be the unconscious awakening of a spiritual conception of a creative and sustaining power in the universe. This new and more vital conception which supersedes the old mythological modes of thought is not altogether independent of them. Lucretius still interprets the world by analogies and illustrations which attach personal attributes to different phases and forces of Nature. Thus he speaks of Aether as the fructifying father, of Earth as the great mother of all living things. But the survival of the mythological conception of the universe, blended indeed with other modes of imaginative thought, appears most conspicuously in the famous invocation to the poem,-- Aeneadum genetrix, hominum divomque voluptas, Alma Venus.