Dualistic cosmology
Moral dualism is the belief of the great complement of, or conflict between, the benevolent and the malevolent. It simply implies that there are two moral opposites at work, independent of any interpretation of what might be "moral" and independent of how these may be represented. Moral opposites might, for example, exist in a worldview which has one god, more than one god, or none. By contrast, duotheism, bitheism or ditheism implies (at least) two gods. While bitheism implies harmony, ditheism implies rivalry and opposition, such as between good and evil, or light and dark, or summer and winter. For example, a ditheistic system could be one in which one god is a creator, and the other a destroyer. In theology, dualism can also refer to the relationship between the deity and creation or the deity and the universe (see theistic dualism). This form of dualism is a belief shared in certain traditions of Christianity and Hinduism. Alternatively, in ontological dualism, the world is divided into two overarching categories. The opposition and combination of the universe's two basic principles of yin and yang is a large part of Chinese philosophy, and is an important feature of Taoism. It is also discussed in Confucianism.
Wiccan views of divinity
Wiccan theology largely revolves around ontological dualism. Ontological dualism is traditionally a sacred gender polarity between the complementary polar opposites of male and female, who are regarded as divine lovers. This kind of dualism is common to various religions; for example, Taoism, where it is represented through yin and yang, and Hinduism, where the lingam and the yoni are symbols of the sacred sexual union of a supreme god and goddess (often Shiva and Shakti). Ontological dualism is distinct from moral dualism in that moral dualism posits a supreme force of good and a supreme force of evil. There is no supreme force of evil in Wicca.