Ditheism, also known as dualism, refers to the belief in two equal and opposing deities or forces. Some synonyms for ditheism include binary theism, dual theism, or duothetism. Other terms used to refer to similar beliefs include manichaeanism, which emphasizes the eternal conflict between good and evil, and Zoroastrianism, which posits the co-existence of Ahura Mazda, god of light, and Angra Mainyu, god of darkness. Dualistic beliefs can also be found in various traditions, including Gnosticism, Hinduism, and Taoism. Today, ditheism is still present in some modern religious and spiritual movements, such as some forms of paganism and Satanism.