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
Zoroaster be the Avesta. Alternatively, he appears with a mace, the "varza"—usually stylized as a steel rod crowned by a bull's head—that priests carry in their installation ceremony. In other depictions he appears with a raised hand and thoughtfully lifted finger, as if to make a point. Zoroaster is rarely depicted as looking directly at the viewer; instead, he appears to be looking slightly upwards, as if beseeching. Zoroaster is almost always depicted with a beard, this along with other factors bearing similarities to 19th-century portraits of Jesus. A common variant of the Zoroaster images derives from a Sassanid-era rock-face carving.