But Persia introduced dualism as a fundamental principle in religion. It was this that distinguished { 152} Mithraism from other sects and inspired its dogmatic theology and ethics, giving them a rigor and firmness unknown to Roman paganism. It considered the universe from an entirely new point of view and at the same time provided a new goal in life.
Of course, if we understand by dualism the antithesis of mind and matter, of reason and intuition, it appeared at a considerably earlier period in Greek philosophy,[34] where it was one of the leading ideas of neo-Pythagoreanism and of Philo's system. But the distinguishing feature of the doctrine of the magi is the fact that it deified the evil principle, set it up as a rival to the supreme deity, and taught that both had to be worshiped. This system offered an apparently simple solution to the problem of evil, the stumbling block of theologies, and it attracted the cultured minds as well as the masses, to whom it afforded an explanation of their sufferings. Just as the mysteries of Mithra began to spread Plutarch wrote of them favorably and was inclined himself to adopt them.[35] From that time dates the appearance in literature of the anti-gods ([Greek: antitheoi]),[36] under the command of the powers of darkness[37] and arrayed against the celestial spirits, messengers or "angels"[38] of divinity. They were Ahriman's _devas_ struggling with the Yazatas of Ormuzd.
A curious passage in Porphyry[39] shows that the earliest neo-Platonists had already admitted Persian demonology into their system. Below the incorporeal and indivisible supreme being, below the stars and the planets, there were countless spirits.[40] Some of them, the gods of cities and nations, received special names: { 153} the others comprised a nameless multitude. They were divided into two groups. The first were the benevolent spirits that gave fecundity to plants and animals, serenity to nature, and knowledge to men. They acted as intermediaries between gods and men, bearing up to heaven the homage and prayers of the faithful, and down from heaven portents and warnings. The others were wicked spirits inhabiting regions close to the earth and there was no evil that they did not exert every effort to cause.[41] At the same time both violent and cunning, impetuous and crafty, they were the authors of all the calamities that befell the world, such as pestilence, famine, tempests and earthquakes. They kindled evil passions and illicit desires in the hearts of men and provoked war and sedition. They were clever deceivers rejoicing in lies and impostures. They encouraged the phantasmagoria and mystification of the sorcerers[42] and gloated over the bloody sacrifices which magicians offered to them all, but especially to their chief.