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.
Free will
Cartesian dualism holds that the mind is a nonphysical substance, the seat of consciousness and intelligence, and is not identical with physical states of the brain or body. It is suggested that although the two worlds do interact, each retains some measure of autonomy. Under cartesian dualism external mind is responsible for bodily action, although unconscious brain activity is often caused by external events (for example, the instantaneous reaction to being burned). Cartesian dualism implies that the physical world is not deterministic – and in which external mind controls (at least some) physical events, providing an interpretation of incompatibilist free will. Stemming from Cartesian dualism, a formulation sometimes called "interactionalist dualism" suggests a two-way interaction, that some physical events cause some mental acts and some mental acts cause some physical events. One modern vision of the possible separation of mind and body is the "three-world" formulation of Popper. Cartesian dualism and Popper's three worlds are two forms of what is called epistemological pluralism, that is the notion that different epistemological methodologies are necessary to attain a full description of the world. Other forms of epistemological pluralist dualism include psychophysical parallelism and epiphenomenalism. Epistemological pluralism is one view in which the mind-body problem is "not" reducible to the concepts of the natural sciences.