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.
Vivartavada
Buddhist thinkers and teachers have expressed their views on the concept of Duality developed by the Vedic thinkers and teachers. Zen teaches that we should be free from dualities in order to be what we are meant to be, and that duality is due to ego which veils reality from its true essence (explained by Buddhists in terms of non-essence); ego, which is an artificial condition not having a true identity because it is a creation of the mind, and distorts reality in an attempt to perceive what it wants to perceive and not what it is. Taoism teaches that reality is like the un- carved block (the symbol of Tao), one must not carve the block lest "Tao" is changed. Sankara considers "Maya" as a temporary or phenomenal reality and Brahman as the Ultimate reality; and that living in "Maya" the "Jiva" (the 'ego-self') superimposes its own interpretation of reality onto reality, and thus Brahman remains hidden or concealed and "Maya" is viewed as the ultimate reality.