The apprehensions of prejudice gradually subsided, and objections began to be based on grounds less absurd in character. The political opposition also was henceforth founded on a more subtle policy, and on an appreciation of the nature of Christianity. Soon after the middle of the third century we meet with the next attack of a purely literary kind, viz., by Porphyry, the most distinguished opponent that Christianity has yet encountered.(196) The pupil of Longinus, perhaps of Origen,(197) and the biographer and interpreter of Plotinus, he is best known for his logical writings, and for the development of the theory of predication in his introduction to the Categories, which formed the text on which hung the mediæval speculations of scholasticism.(198) His Syrian origin and oriental culture perhaps prepared him for a fusion of East and West, and for admitting a deeper admixture of mysticism into the Neo-Platonic philosophy, of which he was a disciple. The points of his approximation to Christianity are the result of those elements in which heathen philosophy most nearly approached to Christian truth, the development of which was stimulated in minds essentially anti-christian by the effort to find a rival to it. Admirably prepared by his serious and spiritual tone to embrace Christianity, he nevertheless lived a disciple of paganism. His feelings rather than his reason led him to defend national creeds. His philosophy and the Christian, which seemed to be aspirations after the same end, being designed to elevate the spirit above the world of sense, were really radically opposed. Understanding therefore the power of the Christian religion, he felt the necessity for supplanting it; and hoped to do so by spiritualizing the old creeds, which he harmonized with philosophy by means of regarding them as symbolic.(199)