Ethical dualism or, as theorized by Descartes, between thought and extension. Ethical dualism on the other hand highlights the moral dimension instead or in addition to the metaphysical one, and envisions an inherent situation of conflict between two antagonistic forces, like light and darkness, Good and Evil. One of the most known and clear-cut interpretations of ethical dualism is the one conceptualized by Zoroastrianism, the ancient Persian religion, which bases its thought on the figure of the prophet Zoroaster (or Zarathustra), who claimed the existence of two original and contrasting principles, Ahura Mazda and Ahriman, respectively representing the forces of Good and
Medes of the Indo-Iranian word "arta-" (lit. "truth") which is familiar from both Avestan and Old Persian and also examples of theophoric names containing "Maždakku" and also the name "Ahura Mazdā". Scholars disagree whether these are indications of Zoroastrian religion amongst the Medes. Diakonoff believes that "Astyages and perhaps even Cyaxares had already embraced a religion derived from the teachings of Zoroaster" which was not identical with doctrine of Zarathustra and Mary Boyce believes that "the existence of the Magi in Media with their own traditions and forms of worship was an obstacle to Zoroastrian proselytizing there". Boyce wrote that the