Swedenborg's doctrine of correspondences--the theory that natural phenomena actually represent, or rather shadow, unseen spiritual conditions and existence--attracted Blake at first reading, and became so much a part of his mental fibre that one feels certain he would have eventually fought his intellectual way out into this channel of thought had Swedenborg never written. Nature seemed to Blake but the confused and vague copy of something definite and perfect in "Imagination" or "Spirit." "All things exist in the human imagination," and "in every bosom a universe expands," he wrote, and in the human imagination and its reverend preservation and cultivation lay man's only source of divine illumination, he believed. "If the doors of perception were cleansed, everything would appear to man as it is, infinite. For man has closed himself up till he sees all things through narrow chinks in his cavern," are illuminating words of his. Blake's whole effort in life seemed to be the cleansing and spiritualizing of the portals of the senses that he might see and hear and receive as much of the infinite spirit as his humanity could hold. The mission which he put clearly before him always, he expressed in these words in his prophetic poem of "Jerusalem": I rest not from my great task To open the Eternal Worlds, to open the Immortal Eyes Of Man inwards; into the Worlds of Thought, into Eternity Ever expanding in the bosom of God, the Human Imagination. No man ever sought more gallantly to batter down the walls of materialism which were closing round the souls of men, to let in the sweet breath of Spirit, and to unveil the Vision of the Universal Life. The immemorial struggle between the body and the soul of man was never lost sight of by him, though he sometimes seems to deny it, and his letters to Butts from Felpham show something of his acute consciousness of the difficulty of subduing his spectre or "selfhood." "Nature and religion," he announces passionately, "are the fetters of Life." The orthodox narrow unspiritual religion of his time and all times was repugnant to Blake, and aroused all his fiery combative qualities. It seemed to him to be as actually a fetter to the spirit as the carnal nature of man. Religion was to him a matter of intuition, and not a question of creed or dogma at all. He gives a picture of ordinary religious conceptions in the poem called the "Everlasting Gospel": The vision of Christ that thou dost see Is my vision's greatest enemy. Thine is the friend of all mankind; Mine speaks in parables to the blind. Thine loves the same world that mine hates, Thy heaven-doors are my hell-gates. Socrates taught what Miletus Loathed as a nation's bitterest curse; And Caiaphas was, in his own mind, A benefactor to mankind. Both read the Bible day and night; But thou read'st black where I read white.