Materialism is a metaphysical position that treats matter and physical processes as the fundamental basis of reality. In many materialist theories, mental states, consciousness, and other apparently nonphysical phenomena are understood as arising from or depending upon physical structures and processes rather than existing as separate substances. Materialism is closely connected with debates about the Mind-Body Problem, consciousness, causation, monism, dualism, idealism, and the nature of substance, and it represents one major way of explaining the relationship between mind and physical reality.