Ahura Mazda as the one supreme creator

Zoroastrian teaching begins from a refusal. Ahura Mazda, the Wise Lord, is wholly good, and evil does not originate with him. This solves in one move the problem that monotheisms with an omnipotent creator have to address at length, and it does so at a cost the tradition has argued about ever since.

The Gathas, the seventeen hymns attributed to Zarathustra himself and the oldest layer of the Avesta, describe two primal spirits, twins in some readings, who at the beginning made a choice between asha, truth and right order, and druj, the lie. One chose truth, the other the lie, and everything that follows is the working out of that choice. Later Zoroastrian literature, particularly the Pahlavi texts of the ninth century, sets Ahura Mazda or Ohrmazd against Angra Mainyu or Ahriman as cosmic antagonists, describes a limited period of mixture in which the world is contested, and predicts the frashokereti, the final making-wonderful, in which evil is destroyed, the dead are raised, and the world is restored.

The disputed question is what kind of system this is. On one reading it is monotheism with an adversary: Ahura Mazda alone is worshipped, Angra Mainyu is not his creation and not his equal, and his defeat is guaranteed. On another it is a genuine dualism, with two uncreated principles. Zoroastrian communities and scholars divide on this, and the Gathas can be construed either way; a further reading takes the two spirits as aspects within Ahura Mazda's own creative act. The Zurvanite tendency attested in the Sasanian period made both the offspring of Time, and is now extinct.

Because the outcome is contested in time even though it is assured at the end, Zoroastrian ethics carries an unusual weight. Human beings are not spectators to the conflict between truth and the lie; they are recruits, and their thoughts, words and deeds materially strengthen one side or the other. The threefold formula of good thoughts, good words, good deeds is not a summary of pious sentiment but a description of how the war is fought.

Several consequences follow. Asceticism has no place: the material world is Ahura Mazda's good creation and is to be cultivated, not renounced, so agriculture, marriage, honest trade and the care of useful animals are religious acts. Celibacy and fasting, virtues in several neighbouring traditions, are not virtues here. Pollution is taken seriously as the incursion of the hostile power, which explains the elaborate purity code and the practice of exposing the dead rather than burying or burning them, since a corpse must not defile earth or fire.

The historical question of influence on Judaism, Christianity and Islam is genuinely contested and worth stating carefully. Jews encountered Persian rule from the sixth century before the common era onward, and the features that appear in Jewish literature in and after that period, a named adversary, ranked angels, a final judgement, bodily resurrection and a world made new, are all prominent in Zoroastrianism. Some scholars regard the influence as substantial and demonstrable; others point out that the Zoroastrian texts describing these doctrines in developed form were written down centuries later than the Jewish ones, so that the direction of borrowing cannot be established from the manuscript evidence alone. The dating of Zarathustra himself is unsettled, with proposals ranging across a millennium. The parallels are not in dispute; what they show is.