As pure literature, the _Nature of Things_ has all the defects inseparable from a didactic poem, that unstable combination of discordant elements, and from a poem which is not only didactic, but argumentative, and in parts highly controversial. Nor are these difficulties in the least degree evaded or smoothed over by the poet. As a teacher, he is in deadly earnest; as a controversialist, his first object is to refute and convince. The graces of poetry are never for a moment allowed to interfere with the full development of an argument. Much of the poem is a chain of intricate reasoning hammered into verse by sheer force of hand. The ardent imagination of the poet struggles through masses of intractable material which no genius could wholly fuse into a metal pure enough to take perfect form. His language, in the fine prologue to the fourth book of the poem, shows his attitude towards his art very clearly. _Avia Pieridum peragro loca nullius ante Trita solo; iuvat integros accedere fontes Atque haurire, iuvatque novos decerpere flores Insignemque meo capiti petere inde coronam Unde prius milli velarint tempora Musae: Primum quod magnis doceo de rebus, et artis Religionum animum nodis exsolvere pergo, Deinde quod obscura de re tam lucida pango Carmina, musaeo contingens cuncta lepore._ The joy and glory of his art come second in his mind to his passionate love of truth, and the deep moral purport of what he believes to be the one true message for mankind. The human race lies fettered by superstition and ignorance; his mission is to dispel their darkness by that light of truth which is "clearer than the beams of the sun or the shining shafts of day." Spinoza has been called, in a bold figure, "a man drunk with God;" the contemplation of the "nature of things," the physical structure of the universe, and the living and all but impersonate law which forms and sustains it, has the same intoxicating influence over Lucretius. God and man are alike to him bubbles on the ceaseless stream of existence; yet they do not therefore, as they have so often done in other philosophies, fade away to a spectral thinness. His contemplation of existence is no brooding over abstractions; Nature is not in his view the majestic and silent figure before whose unchanging eyes the shifting shadow-shapes go and come; but an essential life, manifesting itself in a million workings, _creatrix, gubernans, daedala rerum_. The universe is filled through all its illimitable spaces by the roar of her working, the ceaseless unexhausted energy with which she alternates life and death.