Philosophy of mind
Dualism is a set of views about the relationship between mind and matter (or body). It begins with the claim that mental phenomena are, in some respects, non-physical. One of the earliest known formulations of mind–body dualism was expressed in the eastern Sankhya and Yoga schools of Hindu philosophy (c. 650 BCE), which divided the world into purusha (mind/spirit) and prakriti (material substance). Specifically, the Yoga Sutra of Patanjali presents an analytical approach to the nature of the mind.
Dualistic cosmology
Alternatively, "dualism" can mean the tendency of humans to perceive and understand the world as being divided into two overarching categories. In this sense, it is dualistic when one perceives a tree as a thing separate from everything surrounding it. This form of ontological dualism exists in Taoism and Confucianism, beliefs that divide the universe into the complementary oppositions of yin and yang. In traditions such as classical Hinduism, Zen Buddhism or Islamic Sufism, a key to enlightenment is "transcending" this sort of dualistic thinking, without merely substituting dualism with monism or pluralism.