Chalmers’s Naturalistic Dualism

Philosopher David Chalmers constructs a “naturalistic dualism” to harmonize what he sees as two undeniable but ostensibly contradictory facts: (i) Mental states of phenomenal consciousness, the subjective experience of inner awareness, cannot be reduced to physical states of the brain. (ii) The physical world, the natural world, is all there is; there is nothing supernatural. (The union of the two constitutes the “hard problem,” Chalmers’ well-known metonymic characterization of the mind-body problem and consciousness studies broadly construed.)

The Hard Problem and the Failure of Materialism

In his classic, (almost) paradigm-shifting book, The Conscious Mind, Chalmers says, “Conscious experience is not logically supervenient on the physical…,” in that “we can conceive of a physically identical world without consciousness (e.g., philosophical zombies)… If this is right, then no reductive explanation of consciousness can succeed. Consciousness must be taken as a fundamental feature of the world, alongside mass, charge, and space-time” (Chalmers, 1996).

To Chalmers, the “failure of materialism leads to a kind of dualism: there are both physical and nonphysical features of the world… But there are many varieties of dualism, and it is important to see just where the argument leads us.” He stresses that the argument “do[es] not lead us to a dualism such as that of Descartes, with a separate realm of mental substance that exerts its own influence on physical processes. The best evidence of contemporary science tells us that the physical world is more or less causally closed: for every physical event, there is a sufficient physical cause. If so, there is no room for a mental ‘ghost in the machine’ to do any extra causal work.” (What about quantum mechanics? “A small loophole may be opened by the existence of quantum indeterminacy,” Chalmers advises, but he argues that “this probably cannot be exploited to yield a causal role for a nonphysical mind.”)

Consciousness as Fundamental, Natural, and Law-Governed

Chalmers’ naturalistic dualism is his comprehensive framework to explain conscious experience (qualia) in a way that is consistent with the scientific worldview but which goes beyond physicalism—at least the physicalism we know today—by asserting that consciousness is a fundamental feature of reality.

Traditionally, when consciousness cannot be reduced to natural, physical processes (i.e., when it cannot be explained in purely material or functional terms), the supernatural is invoked—souls, spirits, acts of God, magical realms, and the like. Chalmers eschews anything supernatural.

Rather, he seeks to build a scientifically sound consciousness, yet one that recognizes its irreducibility to strictly physical processes. He says, “If we take experience as fundamental, then we can go about building a theory of consciousness in the usual way: by proposing fundamental laws that connect experience with physical processes” (Chalmers, 1996).

Thus, when Chalmers rejects reductive physicalism, he does not embrace Cartesian dualism (which posits non-physical substances). Rather, he offers a strong kind of property dualism: while mental properties are distinct and not reducible to physical properties, they are systematically related to physical properties. He speculates that these relationships are governed by psychophysical laws, heretofore unknown but which science can discover, much like physics discovers regularities. Thus, Chalmers’ dualism sits entirely within a naturalistic framework, with no appeal to supernatural causes, such that consciousness is part of the natural order, even if it is non-physical.

In an overview, Chalmers notes, “Where there is a fundamental property, there are fundamental laws. A nonreductive theory of experience will add new principles to the furniture of the basic laws of nature. These basic principles will ultimately carry the explanatory burden in a theory of consciousness” (Chalmers, 1995).

This position, he says, “qualifies as a variety of dualism, as it postulates basic properties over and above the properties invoked by physics. But it is an innocent version of dualism, entirely compatible with the scientific view of the world. Nothing in this approach contradicts anything in physical theory; we simply need to add further bridging principles to explain how experience arises from physical processes. There is nothing particularly spiritual or mystical about this theory… Indeed, the overall structure of this position is entirely naturalistic, allowing that ultimately the universe comes down to a network of basic entities obeying simple laws, and allowing that there may ultimately be a theory of consciousness cast in terms of such laws. If the position is to have a name, a good choice might be naturalistic dualism” (Chalmers, 1995).

See Chalmers’ “double-aspect theory of information” as a possible mechanism for his naturalistic dualism.