Dualism is a philosophical concept that posits the existence of two distinct and fundamental substances or realities. In the context of the mind-body problem, it suggests that the mind and body are separate entities, with the mind representing thoughts and consciousness, while the body represents physical matter. This idea has been notably 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 the mind-body dualism, there are other forms of dualism, such as moral dualism, which contrasts good and evil as opposing forces. Dualism can also be found in various religious and spiritual beliefs, where it often reflects the struggle between opposing principles, such as light and darkness or spirit and matter. This framework helps to explore complex questions about existence, identity, and the nature of reality.