Dualism is a philosophical concept that posits the existence of two distinct and fundamental substances or realities. In the context of mind and body, it suggests that the mind is non-physical and separate from the physical body. This idea is often associated with the philosopher René Descartes, who argued that mental phenomena are non-physical and cannot be fully explained by physical processes. In addition to mind-body dualism, there are other forms of dualism, such as moral dualism, which contrasts good and evil as opposing forces. Dualism raises important questions about the nature of consciousness, identity, and the relationship between the mental and physical worlds.