The quiet and worshipful spirit, won by the cultivation of the emotions appropriate to the presence of nature and society, is the mark of the completest life and the most acceptable service. Thus for Wordsworth the meaning of life is inseparable from the meaning of the universe. In apprehending that which is good and beautiful in human experience, he was attended by a vision of the totality of things. Herein he has had to do, if not with the form, at any rate with the very substance of philosophy. [Sidenote: Dante.] § 13. Unquestionably the supreme philosopher-poet is Dante. He is not only philosophical in the temper of his mind, but his greatest poem is the incarnation of a definite system of philosophy, the most definite that the world has seen. That conception of the world which in the thirteenth century found argumentative and orderly expression in the "Summa Theologiæ" of Thomas of Aquino, and constituted the faith of the church, is visualized by Dante, and made the basis of an interpretation of life. The "Divina Commedia" deals with all the heavens to the Empyrean itself, and with all spiritual life to the very presence of God. It derives its imagery from the cosmology of the day, its dramatic motive from the Christian and Greek conceptions of God and his dealings with the world. Sin is punished because of the justice of God; knowledge, virtue, and faith lead, through God's grace and mercy manifested in Christ, to a perpetual union with Him. Hell, purgatory, and paradise give place and setting to the events of the drama. But the deeper meaning of the poem is allegorical. In a letter quoted by Lowell, Dante writes: "The literal subject of the whole work is the state of the soul after death, simply considered. But if the work be taken allegorically the subject is man, as by merit or demerit, through freedom of the will, he renders himself liable to the reward or punishment of justice."[43:4] In other words, the inner and essential meaning of the poem has to do not with external retribution, but with character, and the laws which determine its own proper ruin or perfection. The punishments described in the "Inferno" are accounts of the state of guilt itself, implications of the will that has chosen the part of brutishness. Sin itself is damnable and deadening, but the knowledge that the soul that sinneth shall die is the first way of emancipation from sin. The guidance of Virgil through hell and purgatory signifies the knowledge of good and evil, or moral insight, as the guide of man through this life of struggle and progress. The earthly paradise, at the close of the "Purgatorio," represents the highest state to which human character can attain when choice is determined by ordinary experience, intelligence, and understanding. Here man stands alone, endowed with an enlightened conscience. Here are uttered the last words of Virgil to Dante, the explorer of the spiritual country: