Neutral Monism—Overview

Monism is the theory that all of reality consists of exactly one concrete object or thing, and everything that exists is, in some sense, that one concrete object or thing (Schaffer, 2018). To be precise, this is existence monism. The related view that admits dependent proper parts, on which the whole is prior to its parts, is what Schaffer calls priority monism. Monism also names a family of doctrines about one fundamental kind rather than one object, and it is in that sense that materialism, idealism, and neutral monism are all monisms.

Neutral monism is a different claim. It is the theory that the fundamental nature of reality is neither mental nor physical but neutral between them, with mind and matter alike arising as constructions, aspects, or organizations of that common base. It is monist in holding that everything basic is of one kind of stuff, agreeing that far with materialism and idealism, and distinguished from them by its claim about what that one kind of stuff intrinsically is. It is neither mental nor physical, but that from which both are constructed.

Because neutral monism seeks to account for both mental and physical aspects of reality—avoiding the interaction problem of dualism, the explanatory weakness of materialism, and the decombination problem of idealism—it stands as a major category of consciousness. In one way or another, neutral monism must cover or contain everything we call mental as well as everything we call physical. (The existence of various expressions or kinds of monisms does not much affect how monisms are theories of consciousness.)

There is substantial and obvious articulation, or overlap, between Neutral Monism and Panpsychism. Both are motivated by the need to integrate consciousness into the deep nature of reality; thus, monism theories have panpsychism features, and panpsychism theories can be seen as monisms (to first approximations). Perhaps it is simply the case of each reinforcing the other, as closely allied stances on the fundamental nature of ultimate reality, differing more in historical and theoretical perspective than in substance.

However, they are not entirely the same. Panpsychism holds that the fundamental entities themselves have phenomenal or protophenomenal properties, so the base is already mind-like; Neutral Monism holds that the base is neither mental nor physical, with both arising from it. The difference concerns the character of what is fundamental rather than how much of it there is—though it is not intuitively obvious that the distinction makes much practical difference. Separate categories for Neutral Monism and Panpsychism are certainly justified, yet the boundary can be fuzzy.

In the psychosocial structure of consciousness studies, it would seem that almost everyone would like to be a Monist, because reality just seems more parsimonious with only one kind of thing, one stuff, rather than with two (i.e., Dualism), or, who knows, even with more. If the theory has a clear description of its monistic structure, its one kind of stuff, then it would be classified there (e.g., Idealism). The Neutral Monist theories here stress their monistic nature (which sounds like, but is not, a tautology).

Note that Leibniz exposes a strain in the Neutral Monism category, though not the one it first appears to be. His monadology is a pluralism—infinitely many simple substances—but that alone is no departure, since standard neutral monism is likewise pluralist about its basic elements: Mach's sensations, James's pure experiences, and Russell's percepts are many, not one. Monism here is about kind, not number. The actual strain is that Leibniz's monads are immaterial perceiving substances, so his fundamental kind is mental rather than neutral between the mental and the physical. His presence in this category rests on the structure of pre-established harmony, under which mental and bodily series correspond exactly without interacting—which is formally what neutral and dual-aspect views claim about one reality expressed twice. Spinoza and Leibniz thus sit together under one heading while differing on number—one substance against infinitely many—which is a further sign that the category tracks unity of nature rather than unity of substance. Davidson strains the category from the opposite direction: anomalous monism is a monism about events, but the base it identifies is physical rather than neutral, which is why it is also frequently classed under Non-Reductive Physicalism.

Moreover, some of the theories or ways of thinking that follow are categorized under Neutral Monism because all other categories seem less appropriate, imposing a belief system that should not apply. (I[RLK] hope each of these theories feels less uncomfortable in Neutral Monism than it might have in other categories.)