Naturalistic Dualism and Idealism

a term paper for Philosophy 153

by Delia Morgan

“What is it like to be a thermostat?” In attempting to address the fundamental questions concerning consciousness and its relation to the physical world, David Chalmers takes an unusual approach. Most modern philosophers take a materialist position, holding that reality is fundamentally physical, and that consciousness must ultimately be explainable in terms of the physical properties of the universe, whether it be due to the material composition of nervous systems or the way the physical matter is functionally organized. This view holds that consciousness is ultimately reducible to physical stuff and/or physical processes. Chalmers, however, begins by “taking consciousness seriously.” He takes to task those who would reduce the hard problem of consciousness to the more trivial problem of behavior – what’s detectable to an outside observer. The real problem of consciousness, what is difficult to explain, is conscious from the inside -- why we have conscious experience at all, why it seems like anything to be a conscious being. This phenomenal aspect of consciousness, the qualia of conscious experience, he contends, is the real mystery, and one not reducible to physics as we now conceive it.

Instead, Chalmers embraces a variety of dualism, albeit one with strong overtones of both functionalism and epiphenomenalism; he calls his view “naturalistic dualism.” It differs considerably from the substance dualism of Descartes and other earlier philosophers, which held that there are two different substances in the universe – mind and matter; this is a form of property dualism, which holds that while there may be ultimately one kind of thing in the universe, it has two different aspects, or properties – in this case, phenomenal and physical. This ultimately leads to some interesting implications, such as panpsychism – the idea that conscious experience is ubiquitous, present in rocks, atoms, and thermostats, as well as in the cells of our own bodies. This paper will give a brief overview of Chalmers’ position, and also consider that some of the points he raises in favor of naturalistic dualism would fit equally well with a form of idealism – the position that consciousness itself is the fundamental reality, and the physical universe is a manifestation of that consciousness.

Chalmers’ book The Conscious Mind is subtitled “In Search of a Fundamental Theory.” While the author makes no claim to have achieved such a theory, he aims to set out a few criteria and constraints, and to point in some interesting directions. He starts with three basic constraints: take consciousness seriously; take science seriously; and take consciousness to be a natural phenomenon, subject to natural laws. He hopes for a scientific theory of consciousness, but points out that the natural laws concerning consciousness may not necessarily be physical laws, but might be expected to be laws of quite a different kind. (DC, xiii) This distinction between the natural and the physical is one that is frequently glossed over by materialists; nature is often assumed to be purely physical, and the physical, furthermore, is often conflated with the material. That there are nonmaterial physical entities such as fields and forces, and that the laws of nature are themselves mathematical rather than physical, is frequently overlooked in the materialist view.

Chalmers builds his case for dualism largely on the argument from logical supervenience. Consciousness, he claims, is something of a surprise. Given all the known physical facts about the world, one could imagine explaining the way the world works in a coherent scientific way, including all of the behavior in all of the biological creatures caused by their various neuron firings, without having any indication at all that they have conscious experiences. The subjective qualities of conscious experience are something extra, something added onto the mere physical facts of the world; they do not derive from those facts with logical necessity. In fact, the only way we know about the existence of consciousness at all is because we experience it directly. Thus, consciousness is not “logically supervenient” on the physical; it is not logically necessary, given all the parameters of the physical world, that it should also contain consciousness. (DC, 35) One can imagine a “zombie world” – a logically possible world which is physically identical to our own but lacking in any conscious experience. (DC, 94) In that world the same physical configuration would not give rise to consciousness; therefore, consciousness cannot be derived from or reduced to merely the physical configuration of the world. This is his basic argument against materialism and reductionism, and he returns to it in a variety of forms.

Besides the zombie world, Chalmers offers a number of well-known arguments against reductionism. One is the “inverted spectrum” possibility – one can imagine that another person, with identical physiology, experiences blue the way we experience red, and vice-versa; there are no physical laws to prevent this, which seems to argue against the idea that qualia, or subjective experience, of color is reducible to physical facts. (DC, 99) The “knowledge argument” runs along similar lines: imagine a person raised since birth in such a way that she sees only black and white. Even after she learns all the physical facts about the world, including the facts about light and color and vision, she still does not know what the experience of color is like; when she first sees the color red, it would seem that she has gained some new knowledge about the world. This would imply that the set of physical facts does not exhaust the set of all facts; in other words, there are nonphysical facts in addition to physical ones, and so experiences like color cannot be reduced to physical facts. (DC, 103)

The argument from “epistemic asymmetry” is perhaps the strongest argument against reductionism; it relates to Chalmers’ earlier point about consciousness being a surprising feature of the universe. There is a fundamental difference in the way that we know consciousness versus the way that we know anything else; we know our own consciousness directly, and we can never know the consciousness of another in that way. “Our grounds for belief in consciousness derive solely from our own experience of it...Eliminativism about conscious experience is an unreasonable position only because of our own acquaintance with it. If it were not for this direct knowledge, consciousness could go the way of the vital spirit.” [i.e., it would be considered a mystical or superstitious figment of the imagination, and best done away with] (DC, 101-102) Given this direct knowledge, Chalmers has not much patience for those who would say that consciousness is an “illusion”: “I have little idea what this could even mean. It seems to me that we are surer of the existence of conscious experience than we are of anything else in the world.” (DC, xii) Indeed, it would seem to be an incoherent idea to suggest that a nonconscious entity could have an “illusion” in the first place. Some would even insist that we offer “proof” of the existence of our own consciousness. Proof is obviously not possible, but “we know about consciousness more directly than we know about anything else, so ‘proof’ is inappropriate.” (DC, xiii)

Returning to his main argument, Chalmers says “The failure of consciousness to logically supervene on the physical tells us that no reductive explanation of consciousness can succeed. Given any account of the physical processes purported to underlie consciousness, there will always be a further question: Why are these processes accompanied by conscious experience?” (DC, 106) After establishing the grounds for taking consciousness seriously, and presenting arguments against its reduction to physical terms, Chalmers proceeds to critique various cognitive models, none of which solve the central problem of conscious experience. Some approaches appeal to the “new physics,” namely quantum theory and relativity. (It should be pointed out that “new” is something of a misnomer, since these theories have been around for nearly a century now.) Some versions appeal to quantum effects in the brain, or to the nonlocality of quantum processes; but this still fails to explain consciousness, since these things could occur without consciousness. (DC, 119)

The most common appeal to quantum theory posits the necessity for a conscious observer in bringing about the collapse of the wave function when a physical parameter is measured. At the quantum level, the value of a physical parameter such as position or momentum is not well-defined, but is best described as a probability distribution – that is, until the act of measurement, when it suddenly takes on a definite numerical value. However, Chalmers correctly points out that “these interpretations...do nothing to provide an explanation of consciousness. Rather, they simply assume the existence of consciousness, and use it to help explain certain physical phenomena...they are certainly not reductive theories.” (DC, 120) Ultimately, physics theories fare no better than neurobiological or cognitive theories when it comes to offering reductive explanations of consciousness.

After these critiques of alternate approaches, Chalmers take up the task of offering what he considers a plausible approach to explaining consciousness. The character of the world is such that it is not entirely constrained by physical facts; consciousness carries phenomenal information, and this is an added constraint upon the world. (DC, 123) The failure of consciousness to logically supervene on the physical implies that materialism is false; therefore Chalmers proposes to entertain a form of dualism. “This failure of materialism leads to a kind of dualism: there are both physical and nonphysical features of the world.” (DC, 124) Of course, there is another option he neglects here: why, one might ask, not consider a form of idealism? After all, he has already admitted that we are surer of consciousness than anything else -- i.e., the physical world. Despite this, however, Chalmers seems to do what many other philosophers have done – namely, dismiss idealism without serious consideration. This is unfortunate, as many of his arguments would seem to support a form of idealism as well as, or even better than, the dualistic view that he advocates.

We recall Chalmers’ initial constraints: take consciousness seriously, take science seriously, and take consciousness as a natural phenomenon. One suspects that Chalmers may think the last two are incompatible with idealism; but modern versions of idealism, some of which have been put forward by physicists, are perhaps more compatible with the quirks of the quantum realm than either dualism or materialism is. Furthermore, quantum physics and relativity has raised questions about just what nature itself is. Old ideas about matter as stuff have largely been displaced by the world as a dynamic process of probabilistic flux; old ideas of space and time as constituting an absolute frame of reference have given way to a squishy, relative, dynamic and even discontinuous web of spacetime. Nature has begun to look pretty weird, indeed. By comparison, even idealism ceases to look all that strange.

We will return to this possibility later, after considering Chalmers’ favored position. For the moment, we will be content to point out that he seems to have a fourth, unstated constraint: namely, take the idea of physical stuff seriously, as something existing independently of consciousness and our perceptions. That such a constraint should be implicitly assumed, by Chalmers and others, despite the questions raised by modern physics, perhaps says much about the stubborn grip that common everyday notions, fed by our sense experiences, maintain on the psyche. Another key criterion, related to the one above, and to which Chalmers returns repeatedly is that of the causal closure of the physical world: physical events have only physical causes, and there is no room in the picture for a mental “ghost in the machine” to do any causal work. (DC, 125)

He claims this on “the best evidence of contemporary science” while still allowing that “a small loophole may be opened by the existence of quantum indeterminacy.” However, given that quantum mechanics forms the basis for all material behavior, there is a chance that the loophole is not all that small. On the quantum scale causality becomes questionable; the behavior of particles is not deterministic but fundamentally unpredictable. While this unpredictability appears to wash out on a larger scale, there are complex macroscopic systems with nonlinear or even chaotic behavior which may amplify quantum effects to a noticeable degree. Chalmers argues that even quantum indeterminacy cannot allow for a causal role for consciousness; however, his arguments for this are questionable (see below), and he admits that the entire idea of causality is inescapably “mysterious.” (DC, 150)

Chalmers goes on to propose naturalistic dualism, which is a variety of property dualism. Earlier he had proposed a kind of dualism of mind, in that he distinguished between the phenomenal and the psychological concepts of mind: the phenomenal deals with the qualia of conscious experience, and the psychological deals with mind as the causal basis for behavior. “On the phenomenal concept, mind is characterized by the way it feels; on the psychological concept, mind is characterized by what it does...they cover different phenomena, both of which are quite real.” (DC, 11) Thus, there are two mind-body problems: the easy one (i.e., behavior) posed by the psychological concept, and the hard problem (i.e., conscious experience) posed by the phenomenal concept. (DC, 27) Generally materialists have focused on the first and dismissed the second; it is the second that Chalmers demands be taken seriously. He uses the word “awareness” to refer to the psychological aspect of mind, and “consciousness” to refer to the phenomenal aspect; these two properties “co-occur” and it may be that every phenomenal state corresponds to a psychological state.

Expanding upon this idea of the double aspect, Chalmers suggests a view in which both phenomenal and physical aspects are deeply embedded in the fundamental constituents of nature, and their relations are governed by natural “psychophysical” laws. (DC, 127) Still, consciousness plays no causal role, but merely “arises from a physical substrate in virtue of certain contingent laws of nature.” (DC, 125) One interesting feature of this view is that these contingent psychophysical laws are “not themselves implied by physical laws” (125); this would not violate the causal closure of the physical, so long as these laws only allow for matter affecting mind, rather than vice-versa. This sounds like epiphenomenalism – the view that both mind and matter exist, but the interaction is one way only, with mind dependent upon matter; and indeed, Chalmers addresses the epiphenomenalism issue by saying that it is hard to avoid. (DC, 150)

His view differs from the view of epiphenomenalism in that conscious experience need not arise from the complexities of brain activity, but rather phenomenal aspects may be a fundamental property of nature at its simplest levels, part of the intrinsic nature of the physical world. (DC, 153) In other words, consciousness is not an emergent property of complex systems but an property that extends to the quantum scale; this is a panpsychist view in which conscious experience is everywhere and in everything. He also says that, while he regards his view as a kind of dualism, it could possibly turn out to be a kind of monism: “Perhaps the physical and the phenomenal will turn out to be two different aspects of a single encompassing kind...but...it cannot be a materialist monism.” (DC, 129) Again, he seems to disregard the idea that what he is describing could be anything like idealistic monism; but in actuality it comes quite close to the panpsychist idealistic monism of the Advaita Vedanta school of philosophy in India.

Chalmers’ model is somewhat similar to the neutral monism proposed by Bertrand Russell, who suggested that “at least some of the intrinsic properties of the physical are themselves a variety of phenomenal property.” (DC, 154) Although this “sounds wild,” Chalmers correctly points out that “After all, we really have no idea about the intrinsic properties of the physical. Their nature is up for grabs, and phenomenal properties seem as likely a candidate as any other.” (154) Again, this is a possibility that is also consistent with idealism, which holds that seeming physical properties are really properties of consciousness.

Chalmers spends most of the book fleshing out his ideas about naturalistic dualism; the full treatment of this model is outside the scope of this paper, but a few points may be noted. First, information plays a key role in what he calls a “double aspect principle.” (DC, 284) The suggestion is that information has two aspects – the physical (its particular instantiation) and the phenomenal (associated experiences arising from the processing of information). In his words: “Experience is information from the inside; physics is information from the outside.” (DC, 305) This would fit interestingly with the “it from bit” theory that the world the universe is a giant computer, a world of pure information states. Another possibility he raises, that the world may be “pure causal flux” would lead to a “strangely insubstantial view of the physical world.” (DC, 153) This view is very close to the “interdependent co-arising” view of Buddhist philosophy, which sees phenomenal existence as an illusion created by a web of interacting causes.

Chalmers also considers, and seems to dismiss, another idea that veers dangerously close to idealism. He says there are two classes of facts that do not supervene logically on particular physical facts: facts about consciousness and facts about causation. These are two “mysteries” and it is natural to speculate that these two might be intimately related by some deep metaphysical tie – “Perhaps...experience itself is a kind of causal nexus.” (DC, 152) That is, causation needs to be realized by something; perhaps it is realized by conscious experience itself. This view, like Chalmers’ own view, leads to panpsychism; but Chalmers’ objection to it is that it still does not address the logical possibility of the zombie world.

Chalmers offers a number of defenses of his dualism; many of these would work equally well for idealism. For example: “There is no a priori principle that says that all natural laws will be physical laws; to deny materialism is not to deny naturalism.” Also, while materialism has the advantage of Occam’s razor – it’s a simpler explanation -- this cannot save materialism, since it is utterly incapable of explaining conscious experience. Another objection is that it cannot explain how the physical and the nonphysical interact; Chalmers says “they interact by virtue of psychophysical laws.” He acknowledges that his model so far lacks explanatory and predictive power; this is a frequent charge against idealism also. But Chalmers replies: “Even with fundamental physical laws, we cannot find a ‘connection’ that does the work. Things simply happen in accordance with the law; beyond a certain point, there is no asking ‘how.’” If there are “ultimate connections” they are “entirely mysterious in both the physical and psychophysical cases, so the latter poses no special problem here.” (DC, 170) Nor, one may add, does idealism.

Chalmers’ apparent neglect of idealism is puzzling. Chalmers at one point says “it may turn out that the duality of the physical and the phenomenal can be subsumed under a grander monism, but this will not be a monism of the physical alone.” (DC, 130; emphasis added) Why not a monism of the mental alone? Many of the issues that he raises – the irreducibility of conscious experience, the fundamental mysteriousness of the physical, and the likelihood of panpsychism – are entirely consistent with idealism. Yet, when he mentions idealism at all, it is to dismiss some other view as bordering on idealism, as if that in itself were sufficient to nullify any merit it might otherwise have had. One cannot help but wonder just what it is about idealism that provokes such knee-jerk responses in otherwise thoughtful writers.

Our picture of the physical world is one which keeps changing; consciousness, by comparison, is a rather fixed phenomenon. If, in order to explain consciousness in physical terms, one needs to keep changing the rules of the game, perhaps it’s the wrong game. The physical world is deeply mysterious, as are processes of causation. Explanation involves claims about this mysterious quality of causality, which no one seems to be able to adequately define. Trying to explain consciousness in terms of an ultimately unknowable physical world seems bound to run into problems. Consciousness, on the other hand, while it may seem mysterious in light of physical theory, is at least a directly knowable entity, and may, as Chalmers noted, be used to help explain some otherwise puzzling features of modern physics. The argument from implausibility is inadequate, whether used against Chalmers’ naturalistic dualism or against monistic idealism. And the charge that idealism fails to offer any real explanation contains an implicit premise: that is, the idea that consciousness is what requires explaining. If consciousness is the only thing which is directly knowable, perhaps it’s the last thing which should require explaining; perhaps it should instead be taken as a given, and used to explain other, more mysterious things, such as the illusion of material stuff.