Luther had now become possessed with a burning desire to refute, by means of the truth he had newly learned, the teaching and system of that School-theology on which he himself had wasted so much time and labour, and by which he saw that same truth darkened and obstructed. He first attacked Aristotle, the heathen philosopher from whom this theology, he said, received its empty and perverted formalism, whose system of physics was worthless, and who, especially in his conception of moral life and moral good, was blind, since he knew nothing of the essence and ground of true righteousness.