Dual-aspect monism

In the philosophy of mind, dual-aspect monism is the view that the mental and the physical are two aspects of the same substance.

The theory is distinct from neutral monism as the latter is strictly defined. According to neutral monism, the mental and the physical are two ways of organizing or describing the very same elements, which are themselves "neutral," that is, neither physical or mental.

Whereas neutral monism allows the context of a given group of neutral elements to determine whether the group is mental, physical, both, or neither, dual-aspect monism requires that the mental and the physical are differing aspects of a single underlying substance. These two aspects are conceptually distinct, but they are in reality two faces of one substance. In dual-aspect monism, individual mental and physical states or events are coordinated with one another by their single underlying substantial basis.

Notable double-aspect theorists include Baruch Spinoza, Gustav Fechner, Arthur Schopenhauer, George Henry Lewes, and Thomas Nagel.

The Scientist-theologian John Polkinghorne argues for "dual aspect monism" "there is only one stuff in the world (not two - the material and the not yet materiall) in a space where the two contrasting states (material and the space to be material phases, can occur, a physicist might say) this explains our perception of the difference between mind and matter: therefore, mind matters."