Neutral monism

Neutral monism, in philosophy, is the metaphysical view that existence consists of one kind (hence monism) of primal substance, which in itself is neither mental nor physical, but is capable of mental and physical aspects or attributes.

Neutral monism was introduced by the famous 17th century Dutch philosopher Baruch Spinoza. William James propounded it in his essay "Does Consciousness Exist?" in 1904 (reprinted in Essays in Radical Empiricism in 1912). Bertrand Russell espoused the view for a short period.

The American philosopher Donald Davidson advanced a position on mind-body identity he called "anomalous monism," which is related to but probably not exactly the same as these earlier theories. ("Anomalous" here meaning "not-physical-law-governed" rather than "strange.")

Emergent materialism is another form of metaphysical monism that respects both mind and matter.