Ethical Dualism
Zoroastrian dualism is ethical rather than metaphysical.
Unlike absolute dualism with two equal powers, Zoroastrian dualism is ethical: good will ultimately triumph. Angra Mainyu is not equal to Ahura Mazda; he will eventually be defeated completely.
Good shall triumph because it is good, and evil shall perish because it is evil.
This distinguishes Zoroastrian from absolute dualistic systems.
Theological Interpretation
Written about in
- What Zoroastrianism says about good and evil
The two sides are not evenly matched. Good is expected to win because of what it is, which makes this an ethical dualism rather than a balanced one.