From then, his keen dialectic and his satirical spirit (Augustin had formidable powers of ridicule all through his life) were exercised upon the backs of his fellow-religionists. Provisionally, he had admitted as indisputable the basic principles of Manicheeism: first of all, the primordial antagonism of the two substances, the God of Light and the God of Darkness; then, this other dogma, that particles of that Divine Light, which had been carried away in a temporary victory of the army of Darkness, were immersed in certain plants and liquors. Hence, the distinction they made between clean and unclean food. All those foods were pure which contained some part of the Divine Light; impure, those which did not. The purity of food became evident by certain qualities of taste, smell, and appearance. But now Augustin found a good deal of arbitrariness in these distinctions, and a good deal of simplicity in the belief that the Divine Light dwelt in a vegetable. "Are they not ashamed," he said, "to search God with their palates or with their nose? And if His presence is revealed by a special brilliancy, by the goodness of the taste or the smell, why allow that dish and condemn this, which is of equal savour, light, and perfume? "Yea, why do they look upon the golden melon as come out of God's treasure-house, and yet will have none of the golden fat of the ham or the yellow of an egg? Why does the whiteness of lettuce proclaim to them the Divinity, and the whiteness of cream nothing at all? And why this horror of meat? For, look you, roast sucking-pig offers us a brilliant colour, an agreeable smell, and an appetizing taste--sure signs, according to them, of the Divine Presence."... Once started on this topic, Augustin's vivacity has no limits. He even drops into jokes which would offend modern shamefacedness by their Aristophanic breadth. These arguments, to say the truth, did not shake the foundations of the doctrine, and if a doctrine must be judged according to its works, the Manichees might entrench themselves behind their rigid moral rules, and their conduct. Contrary to the more accommodating Catholicism, they paraded a puritan intolerance. But Augustin had found out at Carthage that this austerity was for the most part hypocrisy. At Rome he was thoroughly enlightened.