A theme so vast and all-embracing enabled Dante to inform the whole knowledge of his epoch. The _Commedia_ is the poem of that scholastic theology which absorbed every branch of science and brought the world within the scope of one thought, God. As the _Summa_ of S. Thomas combined philosophy and revelation, so Dante included both the Pagan and Christian dispensations in his scheme. He starts from the wood of terror, where men are assailed by the wild beasts of their passions; and two guides lead him, by the light of knowledge, up to God. The one is Virgil, the other Beatrice--Virgil, who stands for human reason, science, the four cardinal virtues; Beatrice, who symbolizes divine grace, faith formulated in theology, the virtues bestowed on man through Christ for his salvation. Virgil cannot lead the poet beyond Purgatory; because thus far only is human knowledge of avail to elevate and guide the soul. Beatrice lifts him through the spheres of Paradise by contemplation; because the highest summit attained by reason and natural virtue is but the starting point of the true Christian's journey.
The _Commedia_ is thus the drama or the epos of the soul. It condenses all that man has thought or done, can think or do; all that he knows about the universe around him, all that he hopes or fears from the future; his intuition of an incorruptible and ideal order, underlying and controlling the phenomenal world. God, the world and man are brought into one focus; and the interest of the poem is the relation of the individual soul to them, the participation of each human personality in the dramatic action. It need hardly be observed that Dante's solutions of the problems which arise in the development of this theme, are medieval. His physical science has been superseded. His theology is far from approving itself to the general consciousness of Christians in our age. Yet while all must recognize this obvious truth, the essence of the _Commedia_ is indestructible because of its humanity, because of the personality which animates it. Men change far less than the hypotheses of religion and philosophy, which take form from experience as shadows fly before the sun. However these may alter, man remains substantially the same; and Dante penetrated human nature as few have done--was such a man as few have been. The unity and permanence of his poem are in himself. Never was a plan so vast and various permeated so completely with a single self. At once creator and spectator of his vision, neophyte and hierophant, arraigned and judge, he has not only seen hell as the local prison-house of pain, but has felt it as the state of sin within his heart. He has passed through purifying fires; and the songs of Paradise have sounded by anticipation in his ears. Dante is both the singer and the hero of his epic. In him the universal idea of mankind becomes concrete. The continuous experience of this living person who is at one and the same time a figure of each and every soul that ever breathed, and also the real Dante Alighieri, exile from Florence without blame, sustains as on one thread the medley of successive motives which else might lack poetic unity, gives life to a scheme which else might be too abstract. Expanding to embrace the universe, contracting to a point within one breast, the _Commedia_ combines the general and the particular in an individual commensurate with man.