Chalmers on Dualist Consciousness

In his The Conscious Mind, Chalmers argues that consciousness is not physical. Alternatively, semantically speaking, he proposes that materialism is false and that the facts of consciousness are over and above the facts of physics. The central claim is that consciousness is not reducible to physics; it is not logically-supervenient on physical factors and laws.

In what follows, I shall sketch one of Chalmers’ arguments against materialism about consciousness – his argument from the conceivability of a Zombie (or a Zombie World). More importantly, I shall then discuss some of his proposals about the kind of non-materialist framework which might be on the cards. In particular, I shall examine whether Chalmers has overlooked the possibility that consciousness is simply physical of itself, independently of the plausible claim that its features are not implied by conventional physics. The discussion will involve drawing a comparison between the introduction of consciousness as a fundamental or primitive agency in the world and the introduction of electromagnetism into the mechanical physics of the eighteenth and nineteenth centuries, an example that Chalmers himself has flagged as a precedent to illustrate part of his view of the standing of consciousness – naturalistic dualism.

The Zombie Argument for Anti-Materialism

This conceivability argument asserts that we can consistently think of a philosophical-zombie (or zombie-world), that is, one which is physically indistinguishable from me (or from the real world) but either has no consciousness at all or, if it has consciousness, then it differs in character from the extant one. Thus, in particular, we can conceive of an entity physically identical with me which is utterly devoid of consciousness. We can also conceive of a physical clone of me who has consciousness but its details diverge from mine – for example, by inverting my colour experiences. Our ability to conceive of these possibilities demonstrates that my having my physical properties does not imply my having the features of consciousness that I do, in fact, have, and that the features and laws of consciousness are not implied by physical character of the world. Hence, we may conclude that consciousness does not logically supervene on the physical domain. That is to say, there are logically possible situations of which the physical properties are identical but the features of consciousness are different or consciousness is absent.

Chalmers notes that there are parallel arguments to the Zombie argument which can be given in epistemological terms and in terms of difficulties that arise in the analysis of the concept of consciousness. However, as he recognizes, they have something of the same strategic character as the Zombie argument. For example, consider the thought experiment (due to Frank Jackson) of the colour scientist, Mary. Confined to an environment (and experiences) exclusively black, white, and greyscale, she is supposed to know all the physical facts of colour. She then has the experience of red for the first time. The point of the thought experiment is that Mary’s knowledge of all the physical facts associated with colour gives her no knowledge of what the character of her experience will be. Given the strategic similarity of the arguments, I shall not discuss them here, despite their considerable intrinsic interest. My primary concern is to consider the following question and its relation to the Zombie argument: can it be plausibly said that, despite the fact that consciousness is not derivable from contemporary physics, it may be constitutively physical in itself?

If there is some important and non-trivial sense in which we should judge consciousness to be constitutively physical, then the thought experiment of the Zombie has a very different outcome than that intended by Chalmers. For if we find that consciousness is physical, notwithstanding its not being logically-supervenient upon conventionally circumscribed physics, then when I am asked to consider an organism that is physically identical to me, I cannot conceive it to be anything other than conscious in the way that I am. The alleged Zombie will just be physical me – and conscious. Nothing can be physically identical with me and not conscious; there can be no Zombie. My consciousness will be physical not because its features are derivable from conventional physics, but, trivially, because of its own intrinsic physicality. From this point of view, consciousness must be judged to be a complex of physical features over and above those of currently known physics.

In order to make clearer what is at stake in this issue, it will be useful to consider an example of the development of physical theory and experiment which Chalmers himself has highlighted as being instructive for considering how things might be with consciousness. In order to provide a setting for that example, we should briefly set out Chalmer’s notion of Naturalistic Dualism, which is his positive thesis about consciousness being immaterial.

Chalmers’ Naturalistic Dualism

According to Chalmers, consciousness does not logically-supervene on the physical. So consciousness is not reducible to physics. But this does not mean that there is no dependence on the physical. Chalmers is sympathetic to the idea that there is natural supervenience, meaning that there is a systematic dependence of consciousness on the physical. Indeed, leaving aside all the logically possible divergences between the conscious and the physical, he finds it plausible that, in the real world, physically identical creatures will have the same features of consciousness. (124)

Chalmers favours a sort of property dualism. The properties in question are not physical properties; they are not derivable from the world's physics. However, we may say that they are closely aligned. 125 The features of consciousness “arise” from physical complexes, in virtue of the existence of logically contingent laws which are not implied by the physics itself. They are psychophysical supervenience laws. 127 Importantly, Chalmers seems to take these supervenience laws to be a one way street; consciousness arises from the physical and not, apparently, conversely. (This is a curiosity that I shall discuss below under the rubric “Chalmers’ Shadow Reductionism”.) The idea that there should be non-physical laws of nature that implicate new fundamental variables may be strange but Chalmers suggests that we can find something analogous in the case of the introduction of electromagnetic theory into physics. I here quote Chalmers at length 127:

There had been an attempt to explain electromagnetic phenomena in terms of physical laws that were already understood, involving mechanical principles and the like, but this was unsuccessful. It turned out that to explain electromagnetic phenomena, features such as electromagnetic charge and electromagnetic forces had to be taken as fundamental, and Maxwell introduced new fundamental electromagnetic laws. Only this way could the phenomena be explained. In the same way, to explain consciousness, the features and laws of physical theory are not enough. For a theory of consciousness, new fundamental features and laws are needed.

Chalmers’ description of this historical step is striking. His point is relatively narrow. It is that, sometimes, a naturalistic science must introduce new fundamental variables and laws. The point is well taken. However, some issues arise about the contrast between the case of consciousness and the case of electromagnetism.

The first is that despite the fact that electromagnetic theory introduces new fundamental quantities and laws and, especially, despite the fact that electromagnetic theory is not logically supervenient upon the prior, mechanical physics, Chalmers gives no indication that the introduction of electromagnetism establishes any sort of dualism. While introducing new ontology and new laws, electromagnetism doesn’t suggest to Chalmers the further possibility that it involves a fundamental split in the properties of nature. If electromagnetism should warrant the claim of dualism, then does consciousness better go under the description of trialism? This question is not (merely) facetious. There are perspectives on the introduction of electromagnetism to physics which Chalmers ignores as options for consciousness. Rather than quibble with Chalmers over the value of n in “n-ism”, we might consider the possibility that consciousness might be physical, despite its non-reducibility to familiar physics, in a way that is not dissimilar to the way that electromagnetism is properly judged to be physical despite being a supplementation to conventional physics in the nineteenth and early twentieth centuries.

The Introduction of Electromagnetism into Mechanical Physics

The fundamental elements of electromagnetic theory are Maxwell’s Equations and the Lorentz Force Law. They differ in character in a way that bears on Chalmers’ notion that the fundamental laws implicating consciousness are psycho-physical. Let’s look at Maxwell’s equations in their modern differential rather than integral form.

∇ ∙ E = 4πρ .................................................. [1]

∇ ∙ B = 0 ...................................................... [2]

∇ ∧ E = - (1/c) ∂B/∂t ................................... [3]

∇ ∧ B = (4π/c) J + (1/c) ∂E/∂t ....................... [4]

(E, electric field strength; B, magnetic field strength; ρ, electric charge density; J, current density: t, time; c, speed of light; ∇ ∙ , divergence; ∇∧, curl)

These equations are abstract and idealized theoretical representations that are linked with essential experimental phenomena and intermediate level theoretical commitments. However, it is clear that, as fundamental laws, the principles of electromagnetism are, well, electromagnetic. They characterize the relation of electrical field strength to charge density, the structural constraint that there are no magnetic monopoles, the dependency of the electric field on the time evolution of the magnetic field strength, and the dependency of the magnetic field strength on relevant current density and electric field strength. As they stand, they give no explicit mention of familiar quantities from dynamics. Nor are they reducible to familiar dynamical quantities. (They are not logically supervenient upon mechanical physics.) They are, in effect, fundamental variables. On the other hand, let’s consider the Lorentz force law:

F = ρ ( E + (1/c) vB) ................ [5]

(F, force of fields on charged moving particle)

The force in question arises from the presence of an electric field and motion, at velocity v, in a magnetic field.

Now, we might ask which of these laws have a character similar to those that Chalmers sketches in his suggestions about Naturalistic Dualism. Recall that although physical laws and contingencies do not imply laws and contingencies concerning consciousness, Chalmers characterizes the new fundamental laws as psychophysical. From this viewpoint, they seem to have the character of bridge principles which link “effects” in consciousness with “causes” in the physical complexes from which they arise.

Looking again at the electromagnetic laws, we might search out the analogues of the psychophysical ones. They are the bridge principles which link elements of the distinct domains. Which are the electromagnetomechanical principles? Only one candidate seems plausible, and that is the Lorentz law. It links a familiar dynamical quantity, force F, with charge, electric field, and magnetic field. It functions usefully because the dynamical force is commensurable with other forces at play on the test (charged) particle such as gravitation, in the context of its motion and inertial mass. The inertial mass of the gravitationally and electromagnetically "charged" particle may be thought of as a “clearing house” for commensurable dynamical forces.

What I am driving at here is that Chalmers’ description of the fundamental laws involving consciousness suggests that, in the electromagnetic case, only bridge principles like the Lorentz law fit his account. They link the distinct ontological domains. What is missing from Chalmers’ account is any counterpart to Maxwell’s equations, which, as they stand, are exclusively electromagnetic. They do not have the character of bridge principles linking distinct domains; they are autonomous. If the electromagnetic case is a useful guide here, should we not consider more favourably the idea that features of consciousness may be governed not only by psychophysical principles but also by exclusively psychological, mental, principles?

Further, to the extent that electromagnetism is properly regarded as a physical agency – it supplemented mechanical physics without being non-physical, a point that I shall examine shortly – might we not consider the possibility that consciousness is a physical phenomenon, despite its not being derivable from conventional physics?


(to be continued)