These include neutral monism , idealism , traditional materialism , and partial monism . Traditional materialism is the variety of monism which sees that everything is based in the material and physical. Hobbes subscribed to this view. Neutral monism , a doctrine of Hume, Russell, and Mach, denies that reality is based in neither the physical nor the mental, but rather in one particular kind of substance that can be classified as neutral stuff . Phenomenalism , in most instances, is classified under neutral monism .
Idealism is the form of monism which maintains that everything is based in the mental.
The two philosophers most closely associated with idealism were Berkeley and Hegel, the latter's version bases everything in and on the World Spirit. Partial monism holds that if there are many realms of being, then there is still only one substance within one of the realms upon which everything is based.