Physicalism and its Malcontents

Physicalism, something misleadingly called materialism, is the metaphysical position that everything, including mental states and consciousness itself, is physical in nature. In other words, there is no non-physical mind-stuff, soul-stuff or God-stuff of any kind, only physical matter being acted upon by physical forces. Nevertheless, both Frank Jackson in his “Epiphenomenal Qualia” as well as Saul Kripke in his Naming and Necessity offer arguments which are aimed specifically at demonstrating the untenability of physicalism as it applies to mental states. The purpose of this paper will be to briefly consider each of their arguments in turn, as well as provide reasons for why each of their objections is fundamentally flawed.

Frank Jackson’s “knowledge argument” is illustrated quite nicely by his thought experiment about the color scientist named Mary. Mary, for one reason or another, is a brilliant color scientist who has her entire life been isolated from all colors. In fact, she is so brilliant that she, through her studies which are all carried out in her black and white environment, has come to know everything which she can know about color without actually having experienced it herself. This, however, is the rub for Jackson, for he argues that if the physical system actually was the experience of the color red, for example, then her knowing everything about the physical system should constitute a full knowledge of the experience of the color red. Nevertheless, she does not know everything there is to know about experiencing the color red, therefore, argues Jackson, there is something more to the experience of the color red than the mere physical system, something which she will only learn upon her release from her black and white chamber.

There are two issues which I would like to tease apart for analysis, the first being the issue of causality. Having a full and complete knowledge of a causal system, in this case the perception of the color red, does not constitute either being an actual part of that causal system or the causal system being a part of the individual, in this case actually experiencing the color red. The first person perspective simply cannot be conflated with the third person perspective as Jackson here attempts to do.
This leads us to the other issue which Jackson’s argument hinges upon, namely an equivocation on the word “to know,” an equivocation which hinges on the conflation of the first and third person perspectives. Consider Jackson’s argument as he states it most clearly:

1. “Mary (before her release) knows everything physical there is to know about other people.
2. “Mary (before her release) does not know everything there is to know about other people (because she learns something about them on her release).
3. “There are truths about other people (and herself) which escape the physicalist story.”

The equivocation lies in what can be described as the “know that” vs. “know how” distinction. “Knowing that” consists in all knowledge which can be accrued, loosely speaking, from the third person’s perspective, while the “knowing how” only comes by way of first person experience; being a part of the causal system, as opposed to simply studying the system from the outside. While Mary might have “known that the experience of the color red is …” she did not “know how the experience of the color red is.”

We are now in a position to see where Jackson goes wrong in his argument. In (1) he argues that Mary “knows that” everything physical there is to know about the causal system from a third person perspective. It is not the case that she “knows how” everything physical there is to know about the causal system from a first person perspective. Jackson would surely agree with this, for this is exactly what he asserts in (2). Since (3) depends upon the knowledge of (1) and (2) being of the same kind for its validity, and since the knowledge of (1) and (2) are not of the same kind, the conclusion in (3) is invalid.

Kripke’s argument against physicalism follows very closely the reasoning which Descartes employed to establish the mind/body distinction, though with a number of subtle differences. In his book Naming and Necessity Kripke draws a distinction between what he calls “rigid designators” and “contingent designators.” The former are simply names which are used to pick out the object(s) which any given name picks out across all possible worlds in which that object(s) exists. Thus, “C-fibers” designates an object in this world as well as every other possible world in which C-fibers exist, regardless of what they happen to be called within any of those possible worlds; it is the object from the possible worlds which we are concerned with, not the names in each possible world. A contingent designator is simply a description, loosely speaking, of an object which may or may not be true of that object across all possible worlds. “The son born to my mother on September 4th” is a contingent designator, since I exist in many possible worlds in which I was not born on September 4th. “Jeff”, however, is a rigid designator in that for every possible world in which I exist, “Jeff” picks me out.

Thus, “Jeff” is “the son born to my mother on September 4th”, according to Kripke, is not a necessary truth, because there are a number of possible worlds in which the former holds while the latter fails. However, the proper names “the Morning Star” and “the Evening Star” are both rigid designators which pick out the same object. Accordingly, “the Evening Star” is “the Morning Star,” when taken as proper names, could not fail to be true across all possible worlds in which either of them exist. For one to exist is to necessitate that the other exist as well, for they are actually one and the same. Such, argues Kripke, is the nature of the identity relation between rigid designators.

We can now see the problem which Kripke sees for physicalism, namely that “pain” and “C-fibers” are both rigid designators and are taken as identical by physicalists. Nevertheless, he argues, it is surely possible, meaning that it is actually the case in some possible world, that there are C-fibers firing without pain or pain without C-fibers firing. Consequently, the relation between the two is not a necessary relation, and accordingly C-fiber firing cannot be identical with pain as a matter of deductive logic. In this we can see that the primary difference between Kripke’s argument and Descartes’ lies in the latter’s use of God and the former’s use of analytic metaphysics.

There are three lines of thought which make Kripke’s argument, in the end, unpersuasive from where I stand. The first objection which I have to Kripke’s argument is the very use of “possible worlds” talk. I object to this kind of talk for three reasons. First, it is difficult or even impossible to draw the necessary distinctions between logical, physical and biological possibility. Something can be logically possible without being physically possible or physically possible without being biologically possible and in our discussion concerning the biological relation between C-fibers and the experience of pain this is hardly a trivial matter. Indeed, Kripke attempts, rather unsuccessfully to deal with some of these issues in his treatment of the identity of heat with molecular motion, but finds himself forced to work with a highly contrived definition of heat. I believe that the imaginable separability of water from H2O is an insuperable problem for Kripke’s possible worlds talk. Second, we are simply unable to see all the necessary entailments of any given “possible world.” Our vast ignorance of such entailments seriously calls into question our ability to categorize any given state of affairs as being possible or not, be this possibility biological, physical or even logical. Finally, our ideas of what is logical follow from the combination of nature of the actual world in which we find ourselves along with the manner in which we interact with this world. Since the our ideas concerning what is possible are conditioned by the nature of the actual world it makes little sense to use this standard as a measure for other non-actual, but seemingly possible worlds.

Kripke’s redefinition of heat is a clear example of another objection which can be brought against his argument, namely the distinction between what Christopher Hill calls sympathetic imagination and perceptual imagination. This distinction directly parallels the distinction which was drawn in response to Jackson’s argument, in that one must not conflate first and third person perspectives. Hill argues that it is this difference in perspective which provides the epistemic gap between pain and C-fiber firing rather than any gap which might exist ontologically. In fact, Kripke himself exploits this gap in order to image the possibility of molecular motion without any “heat being felt.” It is his redefining heat from something which melts ice, cooks food, etc. (a third person description) to something which is merely experienced or felt by people (a first person description) which allows him to deal with the potential objection that his argument seems to prove too much by allowing for the imaginable separability of heat from molecular motion to establish the non-identity of the two.

The third problem which I see in Kripke’s thesis is that of the explanatory gap, as described by Joseph Levine. Like Hill’s argument, Levine attempts to show that the gap between mental states and physical states is epistemic rather than metaphysical in nature. The reason why it is so easy to imagine the separability of pain from C-fiber firing is that the former has yet to be fully explained in terms of the latter, unlike the case of heat being fully explained in terms of molecular motion. The physicalist claim, according to Levine, is one of reduction rather than explanation; mental states are physical states, but how this happens exactly is still a bit of a mystery. It is in the cloud of mystery that the two appear to be separable when in reality they are not. I take Hill and Levine’s arguments as supportive of my claim that “possible worlds” talk is misleading at best.

In conclusion, I find both the knowledge argument as well as the modal argument against metaphysical physicalism to be lacking. The knowledge argument relies upon both the conflation of the first and third person perspectives in addition to the closely related equivocation on the word “to know.” The modal argument depends on a highly dubious form of thought experiment in which epistemic separability is taken to entail metaphysical distinction. While metaphysical physicalism may not, in the end turn out to be true, these two arguments do little to force such a conclusion.

Bibliography
Saul Kripke: Naming and Necessity as reprinted in Philosophy of the Mind: Classical and Contemporary Readings (Oxford University Press 2002)
Christopher S. Hill: Imaginability, Conceivability, Possibility and the Mind-Body
Problem as reprinted in Philosophy of the Mind: Classical and Contemporary Readings (Oxford University Press 2002)
Joseph Levine: Materialism and Qualia: The Explanatory Gap as reprinted in Philosophy of the Mind: Classical and Contemporary Readings (Oxford University Press 2002)
Frank Jackson: “Epiphenomenal Qualia” as reprinted in Philosophy of the Mind: Classical and Contemporary Readings (Oxford University Press 2002)
Daniel Dennett: Darwin’s Dangerous Idea: Evolution and the Meanings of Life (Touchstone 1995)
George Lakoff and Mark Johnson: Philosophy in the Flesh: The Embodied Mind and its Challenge to Western Thought (Basic Books 1999)