Neutral monism

Neutral monism is an umbrella term for a class of metaphysical theories in the philosophy of mind, concerning the relation of mind to matter. These theories take the fundamental nature of reality to be neither mental nor physical; in other words it is "neutral".

Neutral monism has gained prominence as a potential solution to theoretical issues within the philosophy of mind, specifically the mind–body problem and the hard problem of consciousness. The mind–body problem is the problem of explaining how mind relates to matter. The hard problem is a related philosophical problem targeted at physicalist theories of mind specifically: the problem arises because it is not obvious how a purely physical universe could give rise to conscious experience. This is because physical explanations are mechanistic: that is, they explain phenomena by appealing to underlying functions and structures. And, though explanations of this sort seem to work well for a wide variety of phenomena, conscious experience seems uniquely resistant to functional explanations. As the philosopher David Chalmers has put it: "even when we have explained the performance of all the cognitive and behavioral functions in the vicinity of experience - perceptual discrimination, categorization, internal access, verbal report - there may still remain a further unanswered question: Why is the performance of these functions accompanied by experience?".

With this, there has been growing demand for alternative ontologies (such as neutral monism) that may provide explanatory frameworks more suitable for explaining the existence of consciousness. It has been accepted by several prominent English-speaking philosophers, such as William James and Bertrand Russell.

Since neutral monism provides a potential solution to theoretical problems in the philosophy of mind, it helps to situate neutral monism against its competitors (that is, alternative solutions offered to the same problems). These competing frameworks can be identified by the relationship they draw between mind and matter, and which of the two they take to be more fundamental.

Note that their 'fundamental' is here being used as a technical term. An entity is fundamental if and only if it is irreducible to any other entities. For example, a birthday cake is not fundamental because it can be reduced to its ingredients; a lego-house is not fundamental because it can be reduced to its constituent lego pieces; and a corporation is not fundamental because it can be reduced to its various buildings, employees, and so forth. In contrast, the fundamental interactions of physics are fundamental because they cannot be reduced to any lower-level physical interactions.

Similarly, what is at stake within the philosophy of mind is whether reality has mental properties (such as conscious experience) as fundamental properties. Physicalists would deny this, and insist that consciousness and all mental properties are derivable from some lower-level physical properties (similar to how the properties of water are derivable from H₂O). Idealists, in contrast, believe reality is fundamentally mental, and that physical things are nothing more than mind-dependant perceptions. Dualists play both side of the aisle as they believe that reality consists of both fundamentally mental and fundamentally physical elements, each irreducible to the other. Then there are panpsychists, who believe that everything is both mental and physical (consciousness is what reality looks like 'from the inside' and the physical world is what reality looks like 'from the outside'). Neutral monists break this mold by claiming that the fundamental elements of reality are neither physical nor mental.

Neutral monism is similar to dualism in that both take reality to have both mental and physical properties irreducible to one another. Unlike dualism however, neutral monism does not take these properties to be fundamental or separate from one another from any meaningful sense. Dualism is the view that reality is, broadly speaking, made up of two distinct substances or properties: physical substances/properties and mental substances/properties. Neutral monism, in contrast, takes both mind and matter to supervene on a neutral third substance, which is neither mental nor physical. According to Baruch Spinoza, the mind and the body are dual aspects of Nature or God, which he identified as the only real substance.

While schematic differences and neutral monism are quite stark, contemporary conceptions of the theories overlap in certain key areas. For instance, Chalmers (1996) maintains that the difference between neutral monism and his preferred property dualism can, at times, be mostly semantic.