In the philosophy of mind, double-aspect theory is the view that the mental and the physical are two aspects of the same substance. The theory's relationship to neutral monism is ill-defined, but one proffered distinction says that whereas neutral monism allows the context of a given group of neutral elements to determine whether the group is mental, physical, both, or neither, double-aspect theory requires the mental and the physical to be inseparable and irreducible (though distinct).[1] Double-aspect theorists include Baruch Spinoza, Gustav Fechner, Arthur Schopenhauer, George Henry Lewes, John Polkinghorne and Thomas Nagel. David Chalmers explores a double-aspect view of information.