Review of Naturalism: a Critical Analysis edited by William Lane Craig and J.P. Moreland (Part 4)

This is part 4 in my series of essays on Naturalism: A Critical Analysis, edited by William Lane Craig and J.P. Moreland.

Chapter 6: Naturalism and the Mind
by Charles Taliaferro

Charles Taliaferro is tasked with stirring up trouble for naturalism with respect to mental states and events.  Insofar as one takes the existence of first-person mental states as evidence for an immaterial spirit or soul, naturalism is threatened because it depends on the rejection of all things "supernatural."  Surely, such entities as immaterial spirits or souls tread uncomfortably close to the supernatural; so, if Taliaferro's project is successful, it presents yet another deadly attack on the naturalist's stronghold.

For those familiar with the history of the philosophy of mind, Taliaferro's essay will not add anything terribly new to the field; however, in a book poking as many holes in naturalism as possible, the argument from the mind has an important place.  Taliaferro does a fine job summarizing the various naturalist strategies for avoiding the threats associated with "substantiating" the mind (i.e. awarding the mind the status of a "substance"--something that exists independently of the physical).  Taliaferro basically outlines three broad naturalist strategies for dealing with the mental, offers objections to each of them, then proposes that the mental fits much better within a theistic framework than within a naturalist framework.  I will discuss the three naturalist strategies and Talifierro's responses to them.

Eliminative Materialism

The first naturalist strategy for escaping any problems with the mental is to flat out deny that anything "mental" even exists.  This position is called "eliminative materialism": it aims to "eliminate" the mental in favor of an all-out materialism.  This strategy's virtue is that it makes the naturalist world logically consistent.  One way of thinking of naturalism is that it prides itself on third-person, objective descriptions of reality.  If all that exist are physical objects and forces (entities that are exhaustively described from an objective, third-person point of view) then the absence of anything "mental" or "subjective" in such a world would certainly make that world logically consistent.  So, where one wants to assert that only physical objects exist, one would be best served by eliminating anything remotely "subjective" or "first-person."  Here, the eliminative materialist gains some credibility through logical coherence.  Whatever credibility this eliminativist strategy wins by virtue of logical consistency, though, is equally (if not more so) lost by several difficult problems.  Taliaferro mentions three such problems.

First, Taliaferro says, "A major problem has been the task of developing a version of eliminative materialism that is not self-refuting or self-contradictory.  Some eliminative materialists appear to be in the unenviable position of claiming to believe that there are no beliefs" (135).  Taliaferro uses Paul Churchland as a paradigm example of an eliminative materialist. On page 135, Taliaferro quotes from Churchland's book The Engine of Reason:

"[W]e are now in a position to explain how our vivid sensory experience arises in the sensory cortex of our brains: how the smell of baking bread, the sound of an oboe, the taste of a peach, and the color of a sunrise are all embodied in a vast chorus of neural activity."

Taliaferro draws attention to the fact that Churchland is speaking as if there is some kind of distinct mental state apart from the brain.  Churchland says that sensations "arise" out of the neural activities. But if the eliminativist view is correct, should it not be the case that nothing "arises" from the neural activities of the brain?  Should not there only be "neural states" and nothing more?  By granting that there is something here to explain--sensations, etc.--isn't Churchland simply undermining his own position?  The most consistent position for the eliminativist would be a flat-out denial of everything first-person or subjective.  Alex Rosenberg recently tried (in vain, I would say) to defend this position in his 2011 book The Atheist's Guide to Reality.¹  Rosenberg too, however, could not bring himself to deny that "experiences" exist even though he paradoxically denied that first-person points of views existed.  The funny feature of eliminativsm (and those who attempt to write books advocating it) is that if the view were true, there simply would not be anything to say or write about.  Furthermore, there should not even be the writers themselves!  For if eliminativism were true, neither Churchland nor Rosenberg (if those names could even refer to entities) could have the point of view that eliminativism is true.  Certainly, they could not intelligibly say, "I believe eliminativism is true," because beliefs are mental states just as sensations are mental states.  Eliminativists are supposed to be eliminating those mental states from the universe.  So the charge that eliminative materialism is self-defeating or self-contradictory appears persuasive.

Second, Taliaferro says, "Another difficulty is the ability to accommodate human reasoning" (p.135).  He goes on to say, "In a standard case of reasoning, one accepts a conclusion in virtue of believing the premises of an argument and acting on one's grasp of the nature of entailment....I am skeptical about whether reasoning can be given any intelligible place in our view of what we do when we undertake philosophical reflection...if one does away with beliefs--or, if one acknowledges the existence of beliefs and yet gives them no role to play in a causal explanation of why, say, Jane Doe reasons as she does" (p.138).  Given that Churchland's book is titled The Engine of Reason, it would be bizarre indeed if his eliminativist position rendered reason itself impossible.  Unfortunately for Churchland and other eliminativists, reason (unless its meaning is grossly distorted) crucially depends on beliefs.  Suppose, for example, Smith were presented with the proposition "the earth is flat."  Let us suppose that Smith understands the proposition (ignoring for the moment any difficulties the concept "understand" poses for eliminativism) and is in some way placing his conscious awareness upon it.  Now, absent any beliefs, what would it mean to say Smith affirms or denies this proposition?  Colloquially, we would say that if Smith affirms the proposition, then he believes it is true, and vice versa if he denies the proposition.  But for the eliminativist, this option is eliminated.  The eliminativist has to say something like "Smith's affirming the proposition just means his brain is configured in a certain way."  According to the eliminativist though, the forces that configure brains are physical forces only, not logical principles.  Absent logical principles playing any roles in reasoning, the term reasoning simply loses all meaning.  Thus, reasoning is lost to the eliminativist.

Third, and perhaps most persuasively, Taliaferro says, "A further worry still is that eliminativism is flatly refuted by experience" (p.135).  Obviously, if the eliminativist wishes to say that I don't have a subjective, first-person point of view, the moment I experience just such a subjective, first-person point of view, eliminativism is dead in the water.  The point is analogous to one proposing that no trees exist; should I look outside and see a tree, the proposition is immediately refuted.  Since subjective points of view are not directly observable from the "outside" by someone else, it is certainly harder to verify that other subjective points of view exist; however, my subjective point of view is obvious to me (as yours should be to you) so just the one instance of subjective experience undermines the eliminativist's claim.

Identity Materialism

Whereas eliminativism denies the existence of mental states, identity materialism grants their existence but claims that they are identical with some brain state or other.  Just as water and H2O are, after close inspection, identical, so should mental states and brain states be identical.

At the outset, Taliaferro records this observation:

"Condensing the problem with materialism into the simplest terms, the chief obstacle to identifying a person's mental life with their [sic] body or bodily parts and processes, is that they do not appear to be identical" (p.139).

This observation is easy to see.  Mental states are quite unlike brain states.  Mental states are filled with sensations and intentions whereas brain states are filled with neurons, chemicals, and gray matter.  Nevertheless, identity materialism has been advanced by some philosophers, so it is worth considering.

Taliaferro considers a number of arguments in defense of identity materialism and offers responses to them.  I will only consider one of them here--the one I found most interesting--for the sake of brevity.  Taliaferro offers an argument defended by Georges Rey that appeals to what Taliaferro calls "referential opacity."  Rey lays out an argument that a dualist might give in defense of dualism:

Dualist Argument
(1) My mind has the property of being conceivably unextended.
(2) My body does not have the property of being conceivably unextended.
Therefore (3) My body is not my mind.

Rey's criticism of this argument is that it is too strong and will therefore invalidate almost any identity claim.  Rey offers this argument to illustrate:

Rey's Counterargument
(1*) The tallest mountain has the property of being conceivably different from Mt. Everest.
(2*) Mt. Everest does not have the property of being conceivably different from Mt. Everest.
Therefore (3*) The tallest mountain is not Mt. Everest.

Taliaferro's response to Rey is that Rey's Counterargument does not run parallel to the Dualist Argument.  Taliaferro's exposition of this, though, is not entirely clear to me.  Here's my interpretation.

Taliaferro argues that, in the Mt. Everest case, there is one entity that possess both the property Being the Tallest Mountain and the property Being called Mt. Everest.  Even though those two properties are not identical to each other, a single entity possess them both.  Thus, the properties Being the Tallest Mountain and Being called Mt. Everest are distinct, as the dualist argument asserts the mind and body are distinct; but, it just-so-happens with Rey's Counterargument that the referent of the terms Tallest Mountain and Mt. Everest is a singular entity.  This is discongruent with the original Dualist Argument because the Dualist Argument does not assert that the terms mind and body refer to a singular entity--asserting that there is more than one entity is, in fact, the whole point of the Dualist Argument.

I think Taliaferro is on to something, but it might have served him better to put the arguments a bit more formally to illustrate Rey's mistake.  Rey is essentially arguing against the logic of the Dualist Argument.  He argues that the logic is invalid because it would spoil every possible identity claim, which is absurd.  Water and H2O, for example, are identical identities.  As Taliaferro correctly notes, though, Rey does not construct an argument that is of analogous construction to the Dualist Argument.  First, look at the original Dualist Argument and a version converted into formal terms:

Dualist Argument
(1) My mind has the property of being conceivably unextended.
(2) My body does not have the property of being conceivably unextended.
Therefore (3) My body is not my mind.

Dualist Argument (Formal)
(1') X has the property of being conceivably A
(2') Y does not have the property of being conceivably A
Therefore, (3') X is not Y

Now look at Rey's original counterargument and a version restated formally:

Rey's Counterargument
(1*) The tallest mountain has the property of being conceivably different from Mt. Everest.
(2*) Mt. Everest does not have the property of being conceivably different from Mt. Everest.
Therefore (3*) The tallest mountain is not Mt. Everest.

Rey's Counterargument (Formal)
(1**) X has the property of being conceivably different from Y
(2**) Y does not have the property of being conceivably different from Y
Therefore (3) X is not Y

Now, if we put the formal versions next to each other for comparison, it becomes immediately evident that they are not constructed congruently:

 Dualist Argument (Formal)
(1') X has the property of being conceivably A
(2') Y does not have the property of being conceivably A
Therefore, (3') X is not Y

Rey's Counterargument (Formal)
(1**) X has the property of being conceivably different from Y
(2**) Y does not have the property of being conceivably different from Y
Therefore (3") X is not Y

Notice that Rey substitutes a "Y" in both locations occupied by "A" in the Dualist Argument, yet Rey also preserves "Y" in the locations occupied by "Y" in the Dualist Argument.  This discongruence renders Rey's Counterargument irrelevant to the validity of the Dualist Argument.  In fact, we can easily see that premiss (2**) in Rey's Counterargument is just a tautology: e.g., water does not have the property of being conceivably different from water; Bill does not have the property of being conceivably different from Bill; a circle does not have the property of being conceivably different from a circle, etc.

The dualist, though, is not interested in saying "a body does not have the property of being conceivably different from a body;" a dualist is rather interested in saying "the mind has the property of being conceivably unextended, whereas the body does not."  Thus, the dualist asserts that the referents of the terms "mind" and "body" are not identical.  Whatever entity it is that "mind" picks out in the world, it is not the same entity that the term "body" picks out.  It appears to me, then, that Rey's argument fails to invalidate the Dualist Argument.  If so, then the identity materialist needs another strategy to vindicate its claim.  While considering other strategies defending identity materialism, Taliaferro argues that they fall short of defeating dualism.  I am inclined to agree with his conclusion, but I will not go over those arguments here.  Let's look at the last naturalist strategy to reconcile the mental with the physical.

Nonreductive Materialism

Nonreductive materialists are those who grant the existence of a mental state that is distinct from a physical state, but who nevertheless assert that the mental fits entirely into the physical world anyway.  Taliaferro identifies philosophers like John Searle and Collin McGinn as nonreductive materialists.  Both Searle and McGinn refuse to give up the uniqueness of the mental, but also refuse to give up materialism.  Searle largely stakes his flag on the proposition that we just don't have enough information yet to understand how the physical produces the mental, whereas McGinn supposes that we lack the conceptual machinery to ever comprehend how the mental exists in a physical world.

Taliaferro's approach to these nonreductive materialists is to point out that they appear to be motivated largely by antipathy toward dualism.  Taliaferro quotes McGinn's The Problem of Consciousness:

"It is either eliminativism, or miracles or hidden structure.  Absolute noumenalism is preferable to denying the undeniable or wallowing in the supernatural."

I think it is fair to say, at the very least, that naturalists do not have a compelling explanation of the existence of mental lives.  If one is forced to decide between, on the one hand, materialism and its imprecision in accounting for the mental, and, on the other hand, dualism and its potential to admit of "supernatural" entities, the nonreductive materialists simply prefer the former.  But what grounds this preference?  Taliaferro again considers a few angles the materialist can take, but I'll just focus on the one I find most interesting.

Taliaferro considers the nature of mental causation.  He writes:

"Critics object that dualism leaves us with a complete mystery in terms of mind-body interaction.  How can things so remote interact?  Invoking theism seems to heighten rather than reduce the problem, for doesn't theism require us also to believe that there can be causal interplay between radically distinct levels of reality?  To appeal to theism here would be to explain the obscure in terms of the more obscure" (p.151).

Taliaferro points out that this line of reasoning appears to assume that the only valid form of causation is physical-to-physical.  Dualists wonder, though, why the world must be restricted to only this kind of causation.  On what grounds does one explicate the proposition that no nonphysical-to-physical forms of causation exist?  As discussed in the first two chapters of Naturalism², this sort of proposition is not amenable to scientific verification.  It is rather a philosophical proposition that requires philosophical argument.  But, what sort of argument could aspire to demonstrate that physical-to-physical causation is all that is possible?  Taliaferro closes his chapter by illustrating a few ways theism provides a better framework with which to understand the mental.  He writes:

"[W]e may well see a theistic-dualist philosophy, not as a case of 'wallowing' in the supernatural...but as offering a credible , comprehensive philosophy of nature that is profoundly unified, coherent, and able to account for things that otherwise seem queer and anomalous" (p.153).

Although Taliaferro's chapter does not settle the dispute over the nature of mind, it does accomplish the goal of causing more trouble for naturalism.  Together with the arguments in the other chapters, Taliaferro's essay enhances my confidence in rejecting naturalism.

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<sup>1.See my review of the book here.↩
2. See my reviews of these chapters here and here.↩</sup>