The Two Principles and the Three Moments

Augustine's objection, developed after he left the religion, targets the geometry of the system rather than any single claim within it. If Light and Darkness are both genuinely eternal and independent, he argued, then Light is not omnipotent in any meaningful sense, since something outside it was able to invade and capture part of it, and a god that can be invaded, wounded and diminished is not the god classical theism means by the word at all. The Manichaean answer, that the mixture was a real event with real consequences rather than a metaphor, was exactly what made the ethics that troubled Augustine most, the elaborate dietary rules and restrictions on labor, coherent on its own terms: every act performed on ordinary matter risks harming the trapped Light inside it.

That is also why Manichaean religious practice split its community into two distinct grades, the Elect, bound to strict fasting, celibacy and a diet built around foods believed to hold especially concentrated Light, and the Hearers, who supported the Elect materially and kept looser obligations while hoping for rebirth as one of the Elect in a future life. Augustine belonged to the second group for roughly nine years, which is part of why his later refutation reads less like an outsider's dismissal and more like an argument built from the inside, against a system whose logic he had once found genuinely persuasive.