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Table of Contents
1. Primary Discussion
Introduction
Naturalism vs. the AfR
Formulating the Basic AfR
Three Underlying Problems
The Basics of Reason under Carrier Naturalism
Six Arguments from Reason
1. Argument from Intentionality (AfI)
2. Argument from Truth (AfT)
3. Argument from Mental Causation (AfMC)
4. Argument from Psychological Relevance of Logical Laws (AfPR)
5. Argument from Unity of Consciousness in Rational Inference (AfUC)
6. Argument from Reliability of Rational Faculties (AfRF)
2. Secondary Discussion
Giving the Churchlands a Fairer Shake
Introducing the Question of Computers
Computation and Perception
First: Computation
Second: Perception
1. Propositional Content
2. Intentionality
3. Mindreading
4. Zombies
Ontology of Logic
Reliablism
Five Axioms of Science?
Only Theists Can Invent Science?
We Should Attack Rocks?
Conclusion
Appendix on Philosophia Christi Feature
Endnotes
Introduction
In C.S. Lewis's Dangerous Idea: In Defense of the Argument from Reason (InterVarsity: 2003), Victor Reppert has contributed what is surely the most extensive defense of the so-called "Argument from Reason" yet to appear in print, despite its many (and serious) failings. His first two chapters concern preliminary issues with which I have little disagreement, so I will not address them here—except to point out that Reppert contradicts himself by attacking at great length the Argument from Motive when applied to C.S. Lewis (in chapter 1) but then applies that same argument against Naturalists (on p. 127). But that aside, my present concern is only with the various arguments from reason, and whether any of them achieves what Reppert claims, namely:
Arguments from reason are good arguments in the sense that they provide substantial grounds for rejecting naturalism about the universe and materialism about the mind, and hence a reason for preferring theism about the universe and dualism or some other nonmaterialist view about the mind. (44)
In a nutshell, an argument from reason (hereafter AfR) argues from "the existence of rational thought" to the necessity of theism and the nonphysicality of the human mind, such that "our very thinking" can "provide evidence that theism is true" (45). Reppert traces the AfR back even beyond C.S. Lewis, but concedes that even Lewis needs improvement, providing which is the function of Reppert's book.
In this critique I will not address every scientific and philosophic objection one could raise against Reppert's case. Rather, I will point out what I believe are the most important conceptual flaws in his arguments, and explain in detail how his arguments are ineffective against my own personal worldview. The organization of this critique is in two parts: the first is all one needs to read to get a gist of what's wrong with Reppert's defense of the Argument from Reason; the second part elaborates with more details and other issues not central to the main points made in the first part.
Naturalism vs. the AfR
Reppert first must establish his opponent: metaphysical naturalism. This is essentially his task in chapter three. He defines naturalism correctly as "the view that the natural world is all there is and that there are no supernatural beings," in particular naturalism holds that "whatever takes place in the universe takes place through natural processes and not as the result of supernatural causation" (46-47).[1] He also rightly notes that "the most popular kind of naturalism is known as materialism or physicalism" (47),[2] and it is this particular variety of naturalism that is his main target throughout the book, though he claims his arguments work against all varieties of naturalism.[3]
The feature of naturalism most relevant to the AfR is that "consistent naturalists," as Reppert puts it, "must hold that in the final analysis, events take place by natural necessity and pure chance," meaning either the one or the other, or perhaps a combination of both, but never anything else (87).[4] Therefore, "if some purposive or intentional explanation can be given" for any phenomenon "and no further analysis can be given in non-purposive and nonrational terms" (51) then purpose or intention are somehow basic properties of the universe. But "purposive basic explanations" cannot "be admitted into a naturalist's worldview" (53). Therefore, if one such phenomenon should turn out to be the formation of logical inferences, then "reason must be viewed as a fundamental cause in the universe," which cannot be true on naturalism (51). This is the basic approach of an AfR. And it is valid: if purposive or intentional explanations actually are fundamental for any phenomena, meaning prior to and not reducible to any other mechanical or otherwise nonpurposive or nonintentional explanation, then naturalism must be false.[5]
Therefore, an "argument from reason" must demonstrate the causal irreducibility of some purposive or intentional event, and by definition, the events it focuses on in that category are rational events, namely logical inferences (deductive and inductive).
Formulating the Basic AfR
Paraphrased in the simplest sense, the AfR works like this: naturalism is a belief, but no belief is rational if ultimately nonrational, and naturalism entails that all beliefs are ultimately nonrational, therefore naturalism is not a rational belief. From this it follows that, since there are rational beliefs, but rational beliefs cannot exist if naturalism is true, therefore naturalism is false (and some worldview that allows rational beliefs must be true). Reppert believes he can establish the key premises in these two arguments in many different ways, and this gives rise to several different "formulations" of the AfR.
The key premise (hereafter the Basic AfR Premise) on which all AfR's rest, and which I find the most fault with, is this:
No belief is rationally inferred if it can be fully explained in terms of nonrational causes. (57)
It is this premise that all of the AfR's Reppert presents attempt to establish. The structure of the basic AfR that he presents is valid, in that it does lead to the conclusion that naturalism should be abandoned, if this one key premise is true. For naturalism is certainly a belief, and it is certainly true that naturalism entails that all beliefs are ultimately nonrational, in the sense that belief-formation analyzed to its simplest causal components is a mindless, mechanical process under naturalism.
It should be noted, though, that there is one technical flaw in his argument's extended form, which does not invalidate the negative conclusion, but does invalidate his further positive conclusion that some antinaturalist worldview must therefore be adopted, or that naturalism is definitely false (as opposed to unknowable). The problem in question is a standard example of the fallacy of excluded middle. This is created by Premise 6 on page 54 and Premise 4 on page 58, where he asserts (using the latter formulation, which Reppert regards as the most correct): "If any thesis entails the conclusion that no belief is rationally inferred, then it should be rejected and its denial accepted." This is an invalid condition, in that Reppert has not validly established it as true or even probably true. For the rejection of a thesis does not entail its denial. There is often a middle position, and there is such here: Pyrrhonic Skepticism (PS). That is, one need not adopt any worldview, naturalism or theism. Rather, one can maintain a position of skepticism toward all worldview conclusions (and thus all or most substantive metaphysical theses). Though such a position is often regarded as self-defeating for a variety of reasons, this is not so on a careful formulation. Even Sextus Empiricus, in his treatise Outlines of Pyrrhonism, written nearly two millennia ago, established a careful formulation that directly addresses and overcomes the usual objections (which haven't really changed in two thousand years), and the formal positivism of Ayer and the positivistic pragmatism of Quine both constitute modern variants of the same view. Of course, though I accept its formal validity as an internally consistent position, I reject PS for other reasons, and it may be that Reppert does as well. But in formal terms, since Reppert has not shown this middle position invalid or less acceptable than any alternative, he has not, strictly speaking, proven his case for antinaturalism, even if everything he argues is entirely correct. This is particularly a problem for Reppert, since without such a case, the Premise in question entails its own defeat. For if it is true that we should deny any premise that is not rationally inferred, then if his premise is not rationally inferred, it must be denied as well. For Reppert does not do a very good job of establishing his premise that "there are rational beliefs."
To be fair, Reppert does declare that he will not advance the AfR as a Skeptical Threat argument, based on a brief discussion of the problems such a form of argument presents, and this could count as an attempt to argue "against" PS, though indirectly and incompletely. At any rate, Reppert declares that his AfR will not call "into question the validity of human reasoning" but rather "assum[es] that validity as an established fact" (70), although the argument he presents does not formally vindicate this assertion. We can thus only assume that Reppert rejects PS as an alternative based on some vaguely defined or defended "established facts" that remove it from reasonable consideration. In that I think he is correct, but he has not done the work that would be needed to secure such a position for someone who actually trusts the AfR as he has defined it.
For if the AfR as Reppert formally presents it is correct, it sooner destroys reason than saves it, and therefore to redeem reason he has far more work cut out for him than the average bear. This is only more the case since his "rescue" theory is theism, which, unlike naturalism, requires positing as its fundamental an unobserved entity—yet unobserved entities can only be accessed through reason, the very faculty the AfR destroys. In contrast, though naturalism certainly appeals to many unobserved entities, its fundamental entity (nature) is observable, and therefore if nature alone can offer a sufficient basis for the reliability of reason, then the AfR doesn't even get off the ground, and there is nothing that need be done to restore the reliability of reason—for the evidence of the senses can then be trusted when they confirm reason's reliability. Reppert cannot rely on this route for theism: if the AfR is correct, then he must establish reason as sound before he can use it to establish God as existent. Otherwise, his defense of reason becomes circular.[6]
But this problem only flaws his attempt to argue from the AfR to theism, and I suspect that given time and effort Reppert probably could establish at least an inductive case against PS, and thus establish his more questionable premise as at least probably true, if everything else he argues already is correct. And even without that, his argument, if correct, still defeats naturalism, by leaving only two options: PS or some form of antinaturalism. The AfR is therefore a respectable argument that deserves a naturalist's attention. Any naturalist worldview that does not entail, strongly imply, or successfully argue for the denial of the Basic AfR Premise, cannot be maintained as credible. It is therefore necessary to show how Reppert's arguments for this premise fail to establish it, and how at least one formulation of naturalism can justify its denial.
Three Underlying Problems
Reppert's discussion of the AfR flirts with disaster at several points, where conceptual mistakes threaten to undermine his project, and we should get these issues out of the way first, before giving his arguments their best possible shake.
The first and most fundamental problem is what I shall call the Possibility Fallacy: assuming that having no explanation is equivalent to not being able to have one (e.g. 69-71). The Basic AfR Premise is a global assertion: no belief is rationally inferred if it is explained with nonrational causes. It is thus necessary to prove that it is not even possible for this to happen (a conceptual argument that is pretty hard to carry off), or at the very least that it probably does not actually happen in human brains (an argument that would require a survey of neurophysical data, which Reppert never conducts).
Since Reppert never develops the latter type of argument, he can only ever mean the former. For example, Lewis's "best explanation argument maintains that the necessary conditions for rationality cannot exist in a naturalist universe" (70: emphasis added), by which he must mean any naturalist universe, in other words every naturalist universe that is conceptually possible. That's a pretty tall order. This underlying premise is essential to the Basic AfR Premise. Yet you cannot establish this underlying premise by showing that naturalists have no explanation for the existence of rational inference. For that does not establish the impossibility of such an explanation. But without establishing impossibility, the AfR fails—unless it is reformulated probabilistically, which Reppert never attempts.
There are two ways the AfR could be so reformulated: Reppert could attempt to show that existing brain science data indicate that a naturalist explanation is improbable, even if it is conceptually possible (for example, it would be true only on a set of data materially different from the data we actually have); or Reppert could attempt to show that a naturalist explanation is conceptually impossible in a certain subset of naturalist universes, and then present physical evidence that the universe must belong to that subset of naturalist universes (while, of course, still leaving room for that evidence to be compatible with the actual universe conforming at the same time to no naturalist scheme at all, but to some supernatural scheme instead, like theism). The latter comes closest to characterizing what Reppert actually (though unknowingly and insufficiently) attempts.
Neither argument would be easy to achieve, and I doubt either could be achieved with the presently limited data available. And Reppert certainly accomplishes neither. So that leaves him with the target of a global conceptual absolute, which is extraordinarily hard to prove, especially given the vast complexity and diversity of naturalisms available. To be fair, Reppert is aware of this problem (71) and does attempt to hit such a target with his various AfR's later in the book. But at times he seems to forget this, and acts like proving that naturalists have no explanation is the same thing as proving they can never have one. And that is a fatal mistake. We will revisit this problem when it arises.
Next is the deployment of what I shall call the Causation Fallacy. Reppert endorses Lewis's argument that "the presence of a cause and effect account of a belief is often used to show the absence or irrelevance of a ground and consequent relationship" (63). The point being that, if rational belief can be given a physical cause-and-effect account, then that would show that a ground-and-consequent relationship was actually irrelevant to that belief being formed. From this it would follow that it is conceptually impossible for a naturalist to explain rational inference (causally) without a self-defeating argument.
However, it would be fallacious to argue that "lunchmeat is often baloney, therefore all lunchmeat is baloney." It is obvious what is wrong with such an argument, and this ties right back into my discussion of the Possibility Fallacy above: simply because it just so happens that all false beliefs are formed causally, it does not follow that all causally formed beliefs are false. This is a fallacy of Affirming the Consequent, to which Lewis and Reppert were apparently led by Hasty Generalization. The fact of a belief being causally formed is, after all, a Red Herring: what makes a belief dubious is not that it was causally formed, but that it was formed by a process that was not significantly truth-finding. This is the crucial issue: whether a causal process is significantly truth-finding. This cannot be ascertained by examining whether it is a causal process. Thus, it cannot be said that rational inference cannot be a causal process simply because nonrational inferences are. To be fair again, Reppert tries to avoid this fallacy when he gets to more careful variants of the AfR later on, but we shall see that he doesn't always dodge the ball.
Finally, the most devastating fault of Reppert's book is the painting of straw men and a bad case of Armchair Science: in other words, his failure to interact at several crucial points with the extensive philosophical literature—and even worse, his failure to get acquainted with the latest scientific findings of cognitive science. I will point these failings out as we go.[7] Quite often he simply ignores the naturalist and scientific literature on a subject and declares an issue unresolved that in fact has been resolved many times in many different ways—though Reppert's readers would never know this, because Reppert ignores all these solutions. The solutions may all be failures, but Reppert has to show that they are. At the very least, he is obligated to tell his readers that the proposed solutions exist. Yet often he doesn't even do that. So when he declares that naturalists "invariably fail to explain reason naturalistically" (119) he is asserting what he hasn't even come close to proving—since he hardly interacts with naturalist philosophies at all, much less all of them (as the word "invariably" entails).
Likewise, cognitive science has produced many findings that lead to many plausible solutions to the problems he presents, yet Reppert's discourse often betrays no awareness of this data—for example, the fact that brains compute virtual simulations of their environment, that the experience of a unified consciousness is a post hoc event, that many forms of ordinary computation are employed in the brains even of lower animals (for example, the way visual data is computed into a visual field) and that these systems are evolutionarily related to those computational systems associated now with language and reason, and so on.
There are many works discussing the physiology of intelligence, for example, such as Raymond Cattell's Intelligence: Its Structure, Growth and Action (1987). This is outdated and yet already covers details Reppert never seems aware of. For example, in "The Physiological and Neurological Bases of Intelligence" (pp. 213-54), Cattell discusses early studies of failures in different aspects of logical reasoning in relation to known brain damage, which is the basis for concluding that reason is a physical function. Indeed, any theory of a reasoning brain (including Reppert's) must account for the peculiar facts at hand linking different rational functions with different brain centers. The way the brain fails tells us a lot about how it works. Reppert does not address this. He doesn't even seem aware of it. This does not mean that he can't deal with it. But he certainly must deal with it before he can claim victory, or anything close to it. To the same end, Cattell also discusses evidence that the more abstract a concept or logical relation, the more brain resources it consumes when we entertain it—and, conversely, losses in brain matter degrade such capacity—which again conforms more to physicalism than Reppert's supernatural dualism. And that was fifteen years ago. A huge amount of progress has been made in these areas since. Reppert discusses none of it.
An example of the most recent work can be found in Relational Frame Theory: A Post-Skinnerian Account of Human Language and Cognition (2001). This outlines a neo-behaviorist theory of mind and rational cognition, deeply rooted in scientific evidence, which Reppert seems largely unaware of and unequipped to address. Therein: Steven Hayes, et al., "Relational Frame Theory: A Précis" (pp. 141-54) outlines a physicalist theory of rational cognition; Ian Stewart, et al., "Relations among Relations: Analogies, Metaphors, and Stories" (pp. 73-86) discusses the scientific evidence regarding the neurophysiology of rational cognition; Steven Hayes, et al., "Thinking, Problem-Solving, and Pragmatic Verbal Analysis" (pp. 87-101) discusses scientific evidence regarding the role of language and natural reasoning, and their evolutionary advantages; Dermot Barnes-Holmes, et al., "Understanding and Verbal Regulation" (pp. 103-17) discusses logic as computational rule-following, and the production of intentionality from relational frame perception; and ibid., "Self and Self-Directed Rules" (pp. 119-39) discusses consciousness as a perceptual construct of a self. All issues Reppert tackles. Yet he never even mentions much less addresses any of this scientific evidence or the theories developed to account for it. And relational frame theory isn't the only theoretical treatment of the evidence out there. Many more exist. Reppert deals with none of them.
I had already warned Reppert about both problems—namely, the lack of interaction with printed sources regarding both the science and the naturalist philosophy of mind—before his book went to print, but he seems to have taken no effort to rectify the failing. This makes his book quite deficient as a contribution to philosophy, much less cognitive science—as his book pretends to be: for Reppert is formulating a theory regarding brain function that is well within the purview of existing scientific research and analysis. Just because Reppert posits supernatural entities does not make his theory any less a scientific hypothesis, open to test against the data like any other, which means he cannot ignore the existing data. But even worse than being merely deficient, since each AfR depends on his proving that naturalists can have no response, for him to ignore all the responses proposed (and all the relevant scientific data), and thus effectively pretend there are none, is quite fatal to his entire enterprise.
The Basics of Reason under Carrier Naturalism
Reppert sets out nine propositions that must be true (and, at least potentially, explicably true) on Naturalism, in order for Reason to be trusted as a reliable faculty (73). I agree with them all, except one, though even that I don't reject completely. So I will show how (at least my own version of) naturalism can explain every single one of these propositions. Though many other naturalists have their own responses to the same issues, I will only draw on my own variant of Metaphysical Naturalism which is thoroughly described in my book Sense and Goodness without God: A Defense of Metaphysical Naturalism. The theories I advance here will demonstrate that all nine propositions have the potential of being true on naturalism, and therefore naturalism is not unable to account for Reason. This entails that the Basic AfR Premise is false, and hence so is every version of the AfR that Reppert presents.
Here I will only outline how my theory explains Reppert's nine propositions, and then I will refer back to this summary later when I get to actually defending my theory on each point. Here are his nine propositions:
1. States of mind have a relation to the world we call intentionality, or about-ness.
Cognitive science has established that the brain is a computer that constructs and runs virtual models. All conscious states of mind consist of or connect with one or more virtual models. The relation these virtual models have to the world is that of corresponding or not corresponding to actual systems in the world. Intentionality is an assignment (verbal or attentional) of a relation between the virtual models and the (hypothesized) real systems. Assignment of relation is a decision (conscious or not), and such decisions, as well as virtual models and actual systems, and patterns of correspondence between them, all can and do exist on naturalism, yet these four things are all that are needed for Proposition 1 to be true.
2. Thoughts and beliefs can be either true or false.
From an analysis of data a brain computes varying degrees of confidence that a virtual model does or does not correspond to a real system. If there is such a correspondence, then having confidence in this is a true belief, while having confidence that there isn't such a correspondence would then be a false belief. If there is no such correspondence between the virtual model and reality, then having confidence that there is such a correspondence is a false belief, but having confidence that there isn't such a correspondence would be a true belief. Thus, Proposition 2 only requires the existence of correspondence and confidence, both of which can and do exist on naturalism.
3. Human beings can be in the condition of accepting, rejecting or suspending belief about propositions.
Every meaningful proposition is the content or output of a virtual model (or rather: actual propositions, of actual models; potential propositions, of potential models). Propositions are formulated in a language as an aid to computation, but when they are not formulated, they merely define the content of a nonlinguistic computation of a virtual model. In either case, a brain computes degrees of confidence in any given proposition, by running its corresponding virtual model and comparing it and its output with observational data, or the output of other computations. Thus, when I say I "accept" Proposition A this means that my brain computes a high level of confidence that Virtual Model A corresponds to a system in the real world (or another system in our own or another's brain, as the case may be); while if I "reject" A, then I have a high level of confidence that A does not so correspond; but if I "suspend judgment," then I have a low level of confidence either way. By simply defining "proposition" as I have here, Proposition 3 follows necessarily from Propositions 1 and 2. Therefore naturalism can account for this as well.
4. Logical laws exist.
Logical "laws" are simply rules of computation. Like the laws of physics, which simply describe how the physical universe actually, physically behaves,[8] the laws of logic do nothing more than describe certain kinds of computational procedure. These "laws" are also no different than, for example, the "laws" of agriculture—the rules of conduct that dictate successful cultivation of crops vs. unsuccessful cultivation (when accurately stated in detail and not summarized into rules of thumb). But in both cases, the "laws" are "discovered" as being the best way to take advantage of the way the universe works. Thus, all you need for the laws to exist is a universe that works a certain way—it will automatically follow from the existence of any such universe that there will be a best way to describe and manipulate it, and that "best way" is something humans can discover and then describe. We then name these descriptions "rules" or "laws."
Logical laws are essentially the laws of linguistic communication—whether communicating with oneself (for purposes of computation) or communicating with others (for purposes of transmitting data or conclusions to other "computers"). The moment any language exists, logic exists, for logic is the procedure required for language to succeed. Since it is a procedure, it requires no special supernatural "entities." The laws, when written down, merely describe the behavior of natural entities that successfully communicate (with themselves or others). In other words, they prescribe certain behaviors that are useful, just as agribusiness describes and prescribes certain behaviors that are useful. Therefore, any universe in which computation and communication exist will also automatically contain logical laws. It is physically impossible for it to be otherwise. And since nothing else is needed, just computation and communication, and both exist on naturalism, therefore naturalism inherently entails the existence of logical laws, in just the same way that it entails physical laws and agricultural laws and so on.[9]
5. Human beings are capable of apprehending logical laws.
Human brains evolved the computational ability to discover better ways of doing things, including better ways to think and communicate, but also better ways to grow cabbage or traverse distances or kill, and so on—it's all the same ability: to explore, experiment, compute, and invent better procedures to achieve any goal. Once you have that ability, you automatically have the ability to discover logical laws, just as one can discover agricultural laws. It is just a matter of time and circumstance.[10] And since one of our most potent evolutionary advantages was language, and the procedure entailed by any successful use of language literally is logic, the discovery of the laws of logic was all but inevitable for humans. We thus "apprehend" the procedures required by language and computation the same way we "apprehend" the procedures for cultivating cabbage or manufacturing a spear. It is the same act of perception engaged when we observe that a pattern of marks is a face, or a pattern of sound is a song. If we can perceive these things, then we can perceive any other kind of pattern, including patterns called "procedures." So if perception exists on naturalism, then we can perceive "logical laws" on naturalism.
6. The state of accepting the truth of a proposition plays a crucial causal role in the production of other beliefs, and the propositional content of mental states is relevant to the playing of this causal role.
Brains are computers. As such, the output of one computation (including the output of confidence level) is often physically the input of another computation, and it thereby has a causal effect on that other computation's output. Every conscious computation in the brain is the computation of either a virtual model or data physically connected to or computed from a virtual model (such as a confidence level). Since a proposition literally is the content or output of a virtual model, propositional content therefore literally has a physical-causal effect on further computation that relies on that virtual-model computation (which literally is the "proposition" in question). All this follows from everything I have declared about the other Propositions above. Therefore naturalism can account for Proposition 6, too.
7. The apprehension of logical laws plays a causal role in the acceptance of the conclusion of the argument as true.
Since "logical laws," like "agricultural laws" or "physical laws," are descriptions of things that happen (or that we can make happen, if we follow the procedure involved), and these descriptions are visible as patterns in data, and brains as computers can perceive patterns in data, including patterns that describe things that happen (or that we can make happen, if we follow the procedure involved), it follows that human brains can perceive logical laws, as I've noted already. Just as this perception in the case of agriculture or physics results eventually in our having confidence that following the perceived procedure will improve our cultivation or manipulation of nature, and this is a causal effect (our brains causally compute the perception, the output of which causally affects all future computations that draw on this output as input), so also this perception in the case of logic results eventually in our having confidence that following the perceived procedure will improve our ability to think and communicate. Obviously this is a causal effect in both cases. Since physical causation is all that is needed, and is easily accounted for here, naturalism can account for Proposition 7.
8. The same individual entertains thoughts of the premises and then draws the conclusion.
Singular consciousness is itself a virtual-model computation of certain brain activities. We know for a fact that it is a post hoc construction—the neurophysical data is conclusive on this point. Consciousness follows brain action, by a measurable lapse of time. This suggests that consciousness is a perceptual computation just like all others. In other words, although different parts of the brain do different things, even in the same train of reasoning, one part of the brain (the cerebral cortex) observes and computes relations among the results, and other parts of the brain (such as the hippocampus) coordinate all outputs together into a coherent state of apprehension, and this stitched-and-perceived output has its own causal effect back down upon the individual systems. To put it another way, just as one section of the brain generates a model of what exists in our visual field, by drawing together all kinds of disparate data and computations performed on that data (like color, shape, speed, relation, etc.), another section of our brain generates a model of a "self" to which the brain can physically relate various other outputs of its computational systems.
This organ (the cerebral cortex), with the aid of global synchronizing signals (such as originate in the hippocampus), thereby generates what we call a "unified consciousness." This is both an illusion and a real thing. It is an illusion in the same sense that colors are an illusion—fictions created by our brains to represent photon frequency data. But this is also causally and physically real in the same sense that colors are produced by real things (photons with frequencies of vibration) and have a causal effect on future computation (the photons cause our brains to generate color-perceptions, but it is perception of the colors that then causes the brain to compute other conclusions, without reference again to the original photons or their frequencies of vibration).
Unifying consciousness involves many systems (for example, synchronic "stitching" of brain events is brought about physically by different organs than those that build a self-perception—but the synchrony of brain systems, and its regulation, is still a physically observable phenomenon, and proven necessary for consciousness), but the result is the same as the unifying of the visual field, the unifying of the sound field, and so on: it is a computation of a virtual model of something really going on. It's just that this time the thing that is "going on" is what is going on in the brain, rather than outside of it. But there is no practical difference here. In other words, the cerebral cortex is a sensory organ little different than an eye or an ear (and their attached brain systems): except that just as the eye senses light instead of sound, and an ear sound instead of light, so a cerebral cortex senses patterns of brain activity instead of patterns of light or sound in themselves (which patterns are "sensed" by other sensory organs in the brain, such as the primary visual cortex, and so on).
Thus, setting Proposition 8 as a condition of Reason is both correct and incorrect. It is obviously not true that the same logic gate must do every step of a computation in a computer. Obviously computation involves many disparate logic gates doing their own thing, all causally linked in a complex way. Yet still, the same "complex of circuits" is what takes an input and produces an output (this much Reppert concedes). But this means it remains true that the "same brain" takes the inputs and produces the outputs, following a logical procedure, which is just a category of computational procedure. The existence of a unified consciousness isn't even necessary, as we see that mindless computers can perform every kind of logical procedure humans can. Unified consciousness is useful however, and more importantly, is how we do things, how our computers developed to process data. This obviously affects how Reppert, for example, "sees" logical computation, since he is a computer that employs (the perception of) a unified consciousness to do that. But it does not follow that his (ours) is the only way reasoning can be performed, and as we have seen, we know for a fact that it is not. Truly, there are great advantages to our way, advantages which "mindless" computers lack. But that has to do with the nature of consciousness, not reason, a distinction I will revisit later.
9. Our processes of reasoning provide us with a systematically reliable way of understanding the world around us.
...unless the AfR is correct in concluding that our processes of reasoning cannot do this given the actual observational data at hand (i.e. the observed natural world). Whether he knows it or not, Reppert's argument formally seeks to prove this Proposition 9 false, in order to introduce Theism as a way of making it true again. I have already discussed above the problem he faces with such an approach ("Formulating the Basic AfR"). Of course, I will show Proposition 9 is not false on naturalism, therefore we have no need of a theistic hypothesis. But the central distinction required here derives from what Reppert himself says: he posited as a given that the "validity" of reason is "an established fact" (70), so the only question is not whether reason is reliable—for Reppert concedes that it is from the start—but whether a purely natural universe can produce (evolve) the "reliable reason" that we observe and that Reppert accepts as an established fact. We will show that it can. Therefore, if we are correct, then the AfR fails.
Such is the approach that I will use here. In subsequent sections I will elaborate and defend all the statements I have made above.
Six Arguments from Reason
Reppert deploys six different versions of the AfR (72-85; cf. 86 & 87), each one aimed at establishing the Basic AfR Premise, by focusing each time on a different but equally essential feature of reason. So I will now address in detail each of these arguments in turn.
1. The Argument from Intentionality (AfI)
The Basic AfI Premise is "If naturalism is true, then there is no fact of the matter as to what someone's thought or statement is about" (75). Reppert tries to establish this premise by claiming that intentionality cannot be reduced to physical things or causes. He never really "demonstrates" this much more than asserts it. He quotes C.S. Lewis, for example, musing that "To talk of one bit of matter being true about another bit of matter seems to me to be nonsense" (74), which I shall call the Argument from Lack of Imagination. The problem is that something is only nonsense when it doesn't mean anything. But the propositions belonging to the class in question do mean something. Per my analysis of Propositions 1 and 2 above, "This bit of matter is true about that bit of matter" literally translates as "This system contains a pattern corresponding to a pattern in that system, in such a way that computations performed on this system are believed to match and predict the behavior of that system." This is not nonsense. So Lewis's Argument from Lack of Imagination is easily refuted.
Surely Reppert would agree that for one theory to be "about" something in the real world (our uncle, the universe) it does not have to be true. All that is required is that the person formulating the theory assign that theory to the hypothesized reality. So "X is about Y" translates literally as "the pattern of X hypothetically corresponds to the pattern of Y." In other words, the "aboutness" of a thought is by definition the hypothesis of "correspondingness" between a thought and its object, which is something we choose (consciously or not) to assign to a thought. It is not something that exists apart from that choice.
So when Reppert complains that "if reality is fundamentally physical" then "the state of the world does not uniquely determine what meaning a word has" and therefore "the word just has no determinate meaning" (74) he really doesn't get how language works. Language is a tool—it is a convention invented by humans. Reality does not tell us what a word means. We decide what aspects of reality a word will refer to. Emphasis here: we decide. We create the meaning for words however we want. The universe has nothing to do with it—except in the trivial sense that we (as computational machines) are a part of the universe.
Reppert complains later that such a decision to name something is always itself an intentional act (90), but that is neither true nor relevant. A decision is just a decision—all computers make them, even those with no intentional states. Decisions can thus be adapted to intentional behaviors as easily as any others. Meanwhile, the core engine of intentionality derives from the attentional centers of the brain, possessed and employed by all animals. That's why cats can keep track of their prey, for example—by the same means, we can track the image or thought of, say, our uncle, by attending to it cognitively, a process well understood in neurophysical terms.
Thus, I am certain many words were derived without any deliberate intention behind them, but simply from unthinking practices of sound emulation (think of the words bang, boom, zap, plunk, etc.[11]), originating from attention to sensory data. But even for those words that were assigned by deliberation, the intentional relationship originated with the pre-verbal thought (the hypothesization that X matches Y), and so the buck stops there. Assigning names is merely secondary. The assignment of a relationship (such as "the behavior of model X will predict the behavior of reality Y") comes first. It should come as no surprise that many intentional states are constructed from other intentional states, just as many colors are constructed in our visual field from other colors. But in any such construct, all of the most underlying intentional states will themselves be intentionally basic, and not constructed from other intentional states. They are constructed, instead, from underlying nonintentional physical phenomena, just as colors are.
In short, we create virtual models in our minds of how we think the universe works, then we choose what names to give to each part or element of that virtual model, in order to suit our needs (chief among which being communication, which in turn leads to semantic computation, as we learn to communicate with ourselves). Once we choose to assign the word "white" to "element A of model B" that assignment remains in our computational register: the word evokes (and translates as) that element of that virtual model. That's how communication works: I choose "white" to refer to a certain color pattern, you learn the assignment, and then I can evoke the experience of that color in you by speaking the word "white." The "about-ness" here is purely internal: a computer assigns a label to a repeatable experience. That's it. There is no mystery here, and nothing supernatural going on. It is straightforward computational physics.
Reppert, like Quine, is disturbed by the fact that this just all goes on in our heads. We never know for sure whether "element A of model B" corresponds to any real thing in the universe, much less the very same thing. But that is not a problem for intentionality, only for epistemology—it's the good old fashioned "problem of knowledge." And I am sure Reppert would agree we can still say from time to time that the proposition "element A of model B corresponds to a real thing in the universe, even the very same thing" is probably true, and really mean it—even estimate how probable this is—all based on available data and additional exploration and testing. Moreover, "element A of model B corresponds to a real thing in the universe, even the very same thing" can be a false proposition and still be about the same thing. So the fact that we can't know whether such a proposition is true presents no challenge to the issue of establishing intentionality.
Returning to my earlier definition of aboutness, as long as we can know that "element A of model B is hypothesized to correspond to real item C in the universe" we have intentionality, we have a thought that is about a thing. The thing doesn't even have to exist—the same statement stands even if it is rephrased as "hypothesized real item C in the hypothesized universe." And it is obvious how the proposition "element A of model B is hypothesized to correspond to item C which is hypothesized to be real in the hypothesized universe" can be identified as a true proposition even by a dumb computer. Because the verbal link that alone completely establishes aboutness—the fact of being "hypothesized"—is something that many purely mechanical computers do (a point I will elaborate on later, e.g. "The Argument from the Psychological Relevance of Logical Laws" and "Introducing the Question of Computers"). So there is no question about whether such a proposition can be true in a physical universe, much less any question about how we can know it is true: since we create the relation, we have first-hand knowledge, even knowledge-by-direct-acquaintance, that the proposition is true.
Reppert pulls out Quine's disastrous gavagai analogy in an attempt to prove his point from an alleged ambiguity in language. "There is no fact of the matter," Reppert claims, "as to whether the native is referring to 'rabbit' or 'undetached rabbit parts'" (74-75). But this is not really true. Insofar as 'rabbit' or 'undetached rabbit parts' even have a different meaning (and if they mean the same thing, then Reppert's and Quine's concerns are utterly pointless), then there are many possibilities, none of which was openly considered by Quine—and thus not by Reppert, either. For example: (a) the native doesn't care what the word means or how he may be misusing it; (b) the word (for the native) means only one or the other, and the native knows this; or (c) the word (for the native) means both things (it defines a whole class of objects and not just one object), and the native knows this; or (d) the native isn't sure what the word is supposed to mean, but knows who does (such as his elders). Quine's argument covertly depends on (a), which is rather ridiculous, or (d), which only pushes the issue back to (b) or (c) anyway.
The reality, in most actual, genuine cases of communication, is either (b) or (c)—or (d), which ultimately entails either (b) or (c)—neither of which supports Quine's point. To the contrary, they refute it. And how can you know? Just ask the native "Do you mean by 'gavagai' a 'rabbit' or 'undetached rabbit parts' or can it mean either?" He will tell you. Case closed. How will the native know? Because he learned the language and knows how it is used (and might even be able to point you to a dictionary or living authority on the matter) and, more importantly, he pictured exactly what he meant in his mind before he searched his verbal index for a word corresponding to that picture in his mind, and so now, upon your query, he need only run the procedure in reverse to compute the answer.
The connection between a pattern—let's say, always 'rabbit' and never just 'undetached rabbit parts'—and a word (gavagai) is physically created and strengthened in the brain of the native speaker. And his cerebral cortex can detect this physical connection and use it (to transmit or receive data using its corresponding codeword, or teach the connection to someone else). How did the native's brain learn this precise a connection? By paying attention. Imagine one day he saw (or asked his elder to imagine) a rabbit all chopped up but all its parts sewn back together at random. "Papa, is that still a gavagai?" "No, son. That's just a mangled mess of gavagai parts." Or maybe even: "Yes, son. The word means both." Or perhaps: "We've never encountered that before, so let's make up a rule to cover it right now." So no matter what, there is a fact of the matter after all. But the Argument from Lack of Imagination strikes again, and both Quine and Reppert miss the obvious.[12]
Since the meaning of a word is tied physically in our brains to certain repeatable patterns or assemblies of patterns in experience, there is never any question as to what that word means to us. We can simply crunch the data in our heads and out comes the answer, just by processing the virtual model physically linked to the word (in this case, the model of a gavagai, which is computed from another model: the model of our past observations of, and queries about, the use of the word gavagai). There remains a question as to what the word means to other people, and it is true that it might mean slightly different things to different people, but the more expert and precise a person is, the more their meaning will converge on that of other expert, precise people, and at all events, the set of all the meanings shared by all the people who speak the same language is by definition the conventional meaning known to all. The rest is just a question of rule enforcement: if the experts want the meaning-set that they share to be the convention, they must educate the public accordingly. This is the role served, for example, by dictionaries: to represent an authoritative codebook to educate everyone into sharing the same conventions of meaning. And it is only by seeking to maintain some such enforcement of conventions of meaning that people can communicate at all. And where a word is broad in scope, either officially or by default (e.g. gavagai means both 'rabbit' and 'undetached rabbit parts', which one depending on the context), further explication can generate the needed precision. So even the natural ambiguity in language is overcome by additional communication.
Such is my solution to the Problem of Intentionality. Now, one might play fair and suppose Reppert didn't know my view—though I am pretty sure he did, from email exchanges before the publication of his book. Set that aside. What about other naturalists on the public record? Reppert presents only one philosopher (W. V. Quine) as doubting the reducibility of intentionality, but Reppert hardly even presents Quine's philosophy or his position on issues related to intentionality, much less discusses any rebuttals by other philosophers in print. He merely rests uncritically on one detached example. Thus, Reppert doesn't really demonstrate what he needs to: namely, that no naturalists have a solution to the Problem of Intentionality. In fact, even that would not be enough, since to avoid the Possibility Fallacy he must show that it is impossible for any Naturalist to have a solution (or at the very least that this is improbable), but Reppert makes no case for such a conclusion.
Indeed, Reppert is addressing metaphysical naturalism, yet Quine is not a metaphysical naturalist—to the contrary, he rejects all metaphysics, and instead advances a kind of pragmatic positivism, referring to himself as a naturalist only in the obscure epistemic sense. So where are the metaphysical naturalists? Where is Dennett? Field? Millikan? It does not seem Reppert checked the writings of any such philosophers, except the bizarre fringe group known as "eliminative materialists," yet even then he does not name (here) a single philosopher in that group, much less interact with their philosophies. Though he refers readers to some articles that do this, he does not refer readers to any articles that present, much less rebut, the arguments of any non-eliminative materialists on the issue of intentionality (or related subjects).
Yet the Stanford Encyclopedia of Philosophy tells us that "among philosophers attracted to a physicalist ontology, few have accepted the outright eliminativist materialist denial of the reality of beliefs and desires" and that in fact "a significant number of physicalist philosophers subscribe to the task of reconciling the existence of intentionality with a physicalist ontology."[13] So why don't we hear from them? Why doesn't Reppert discuss them? He certainly must refute them for his AfI to stand any chance. Yet he ignores them completely. Therefore, we can conclude that Reppert has failed to establish the Basic AfI Premise and therefore the AfI remains unproved. And since I have presented a coherent and plausible naturalist account of intentionality, we can go even further and conclude that the Basic AfI Premise is false, and therefore so is the conclusion of the AfI. [For more discussion, see in the secondary part of this critique: "Intentionality" and "Mindreading"]
2. The Argument from Truth (AfT)
The Basic AfT Premise is "If naturalism is true, then no states of the person can be either true or false" (77). As with the AfI, Reppert only argues for this premise by interacting with eliminative materialists—though at least now he actually does interact with and name them (or two of them: the Churchlands). But he still does not even mention much less interact with non-eliminative materialists. Indeed, his entire AfT rests on an unproven conditional: "some theorists...are telling us that we must be prepared to find nothing in the brain that can be true or false, and if such an alarming occurrence take[s] place, the reasonable thing to do would be to deny the existence of truth" (77: emphasis added). That's it. "Some" say this, and "if" they are right, then the conclusion of the AfT is true. That is not adequate to establish that the Basic AfT Premise is true, and therefore Reppert has failed to demonstrate the credibility of his own argument.
We could walk away right now and feel no threat—for no threat has been established. Reppert never mentions much less addresses or considers those naturalists who disagree with the only two people that Reppert cites. And since most metaphysical naturalists disagree with (at least Paul) Churchland on this one point, it is really rather silly of Reppert to claim that metaphysical naturalists have no answer here. And yet he must not only show that (which he has not done), but that all metaphysical naturalists cannot have an answer (which, again, he doesn't do). But I suppose Reppert intended his quotations of the Churchlands to "represent" an attack on those metaphysical naturalists, even though if that is what he intended he was obligated to discuss at least some of the responses to the Churchlands that must be in print, yet he never even mentions any.
Thus, with the AfI and AfT, Reppert really has only attempted two arguments so far against eliminative materialism, not naturalism. And even then, in both cases Reppert's argument consists of little more than begging the question against them: "they" say X does not exist (= Reppert's basic premise in each argument), "I" say it does (= Reppert's second premise in each argument), therefore "they" are wrong. I say "little more" (rather than not at all) because Reppert does not merely assert the second premise, but does try to provide a couple of paragraphs supporting his contention. But his arguments are hardly extensive enough to persuade anyone who might disagree, least of all the eliminative materialists who, far from writing a few paragraphs, have composed entire books arguing their case.[14] And as for the rest of us, who aren't eliminative materialists, it is all side show. Since Reppert only ever addresses them, neither his AfI nor his AfT concerns us.
But I can go one better still. Not only has Reppert not presented any actual AfT against any form of non-eliminative materialism, but my metaphysical naturalism presents a refutation of his Basic AfT Premise, and therefore settles the matter in our favor, not his. And I believe Reppert was aware of my view before he completed his book. As I described above (per my analysis of Propositions 2 and 3), "truth" is the degree to which the pattern of a virtual model computed by a brain corresponds to the pattern of an actual system in the real world. Of course, per the issue of intentionality, not just "any" system, but the particular system we have chosen to assign our virtual model to (as a hypothesized description of it). The real system we reference by accessing the relevant data (looking and pointing) and/or mutual communicated agreement (communicating to each other the fact that we are discussing the same thing—and we can, if necessary, explain how we are to know that we are discussing the same thing and what conditions would have to obtain for us to conclude that we weren't discussing the same thing). But once we have resolved the Problem of Intentionality, the Problem of Truth is easily solved.
If "truth" is the degree to which the pattern of a virtual model computed by a brain corresponds to the pattern of an actual system in the real world, and true "knowledge" is the possession of a belief ("having confidence") that such a correspondence exists when in fact it does, then "truth" can obviously exist in a purely physical world-system. For that correspondence, on which the reality of truth depends, is a physical fact, as is the confidence, on which the reality of knowledge depends.[15] Reppert can only argue against this by (1) presenting physical evidence against the factual elements of my definition (e.g. that the brain computes virtual models, etc.) or by (2) somehow proving that truth cannot mean what I say it means.
Option (2) seems like a fool's errand, since my definition is coherent and explains all relevant uses of the word "truth," and how words are defined is a human invention, and thus humans can simply change the definition of truth to be mine, if in fact any of Reppert's arguments showed they must do so in order to rescue their preferred realist ontology of truth. So that leaves option (1), which is the sort of argument Reppert never attempts. He does not seem interested in the actual details of the leading findings of neurophysiology or cognitive science. Indeed, just about the only times he even mentions such things it is in the quotations of persons who actually agree with all of my facts, the very facts Reppert would need to refute—such as the Churchlands, who outlay the evidence extensively in their books (some of which Reppert even quotes): A Neurocomputational Perspective: The Nature of Mind and the Structure of Science (1989), The Engine of Reason, The Seat of the Soul: A Philosophical Journey into the Brain (1995), Neurophilosophy: Toward a Unified Science of the Mind-Brain (1986), and The Computational Brain (1992). Though I do not agree with the Churchlands on every single point, especially in their interpretations of certain facts, I pretty much agree that they have the actual facts right. And my view is based on those facts.
One example of an interpretation of the facts that the Churchlands (as Reppert represents them) get wrong is precisely what Reppert rests his own case on, which is the view that the interests of survival-advantage would place the interests of truth-finding in the backseat. Such a view is true only so far—it quickly becomes untrue the moment truth-finding itself is hit upon as a survival advantage, in just the same way wings or peacock feathers are hit upon for the very same end. The issue of evolved truth-finding mechanisms is something I will take up in more detail later. For now, observe what Reppert says:
One can pursue effective manipulation of the world, or reproductive fitness, or fame, or glory, or sainthood, but these goals are distinct from the purely epistemic goal of gathering as many (or as high of quality) truths as possible. (77)
Distinct, yes. Unconnected, no. What Reppert seems to miss is that every single one of these goals can be better achieved—faster, more thoroughly, and more efficiently—if one has on hand a generic truth-finding tool to aid him. Therefore, such a tool would definitely confer a survival advantage on anyone who had it—in fact, it would confer an advantage for the achievement of almost every conceivable goal. Imagine two animals: one that has a tool that helps him in almost every conceivable endeavor, and one that lacks such a tool. Who has the advantage? That's a no-brainer (joke intended).
So there can be no doubt that a truth-finding engine is valuable and, if hit upon, would not likely fail to survive and develop. Thus, when Reppert, like Plantinga, supposes that an animal can survive just as well without Reason, he supposes wrong. Yes, an animal can do well without Reason. But they cannot do anywhere near as well as animals who have Reason. That is why humans are the only species in the history of this planet who have been able to sustain themselves at a population many times beyond the natural ecological capacity of their environment, and who have the means to escape nearly every catastrophe that has driven other species extinct (we now have the ability, even if not yet the will, to avoid destruction at the hands of diseases and asteroids, for example—and have long had the ability to escape primitive catastrophes such as fire, flood, famine, and plague).
Thus, Patricia Churchland is right that, as Reppert quotes her, "boiled down to essentials, a nervous system enables the organism to succeed in...feeding, fleeing, fighting, and reproducing" but she is wrong when she (according to Reppert) concludes from this fact that "truth, whatever that is, takes the hindmost" place in importance (76-77). For this is missing the forest for the trees: a truth-finding organ aids "feeding, fleeing, fighting, and reproducing" in a way no other advancement or even array of advancements can ever come close to matching. Thus, it cannot be said that truth takes the hindmost. That is only true for animals who have not developed a truth-finding organ. For animals who have developed such an organ, truth is as vital as the opposable thumb. For it is precisely by being able to construct virtual models of the world and "play them out" in our brains that we can come to understand and predict that world, and make use of that understanding and prediction to benefit, for example, our quest for "differential reproductive success." But this advantage is only gained if we are able to construct, more often than chance, models that match the real world or that approach such a correspondence. And that is what "truth" physically is. Indeed, as I explain in the latter half of this critique, that is pretty much the very same thing the Churchlands argue, contrary to Reppert's mischaracterization (cf. Giving the Churchlands a Fairer Shake).
I must also add before continuing that Churchland's comment, taken by itself (as she probably did not intend it to be), also ignores the fact that it is not all about genetics. It is no longer the case that the "differential reproductive success" of human genomes drives advances in science or reason, or even that it matters much at all anymore. Genetic evolution accounts for the development of a crude truth-finding organ in the human brain. But Reason, as Reppert intends the term, encompasses the formal rules and procedures of various logics, including the logic of the scientific method. And these have not arisen from genetics. They do describe and refine computational processes actually employed by the human brain, but they greatly improve the accuracy and greatly reduce the errors of that mechanism, by restructuring the brain memetically, i.e. through environmental learning, not natural selection.
Most of what humans "are" is not genetic but memetic—for example, consciousness (meaning our actual identity, not the capacity to develop one) is constructed, and is therefore an assembly of memes, not an assembly of genes. Genes do define and limit and create tendencies in how the brain can respond to and assimilate memes, but the mind itself, our "identities" as persons, is largely a memetic system. We are made, not born. It is thus the case now that the "differential reproductive success" of memetic systems (ideologies, ideas, techniques, technologies, etc.) matters far more than that of genetic systems,[16] and any account of the role of evolution in the development of human reason must address the role of the memetic ecology even more than the biological. This is a fact fatally overlooked by Plantinga, for example. It is also missed by Reppert, who should have known better than to conflate the natural reason of the human animal, and the formal reason established by the Greeks and perfected by subsequent inheriting cultures. The one is the function of a biological organ. The other is a technology. The distinction is an important one, as we shall see.
3. The Argument from Mental Causation (AfMC)
The Basic AfMC Premise is "If naturalism is true, then no event can cause another event in virtue of its propositional content" (78). How Reppert gets to this premise takes a little explaining. Here he only discusses deductive reasoning, which is strange since inductive reasoning is more important (e.g. inductive reasoning could explain the "discovery" of deductive reasoning through experience). But we will follow Reppert and assume that deductive reasoning is the important issue here. Appealing to standard Aristotelian syllogistic logic, Reppert says that for "rational inference" to be "possible" then we must come to believe a syllogism's conclusion is true by "being in the state of entertaining and accepting" the major premise and the minor premise, and this state of being must somehow "cause" us to entertain and accept the conclusion. The key move here is that for this to be true, mental events must cause other mental events "in virtue of the propositional content of those events." That much we agree on.
Where we disagree is when Reppert declares that it "might...be the case that the propositional content of these brain states is irrelevant to the way in which they [causally] succeed one another in the brain" (78). Of course, yet again, saying "might" destroys his own argument. If its central premise only "might" be true, then the argument only "might" be true, and that is a useless conclusion, since we want to know whether the argument is true. Yet even his tentative approach is undermined by the fact that on my theory his central premise is false and therefore he is wrong even to claim that it might be true for all naturalisms, as he must claim in order for his AfR to say much of interest to naturalists.
Reppert notes that "if all causation is physical" then "it might be asked how the content of a mental state could possibly be relevant to what causes what in the world" (79). True, it might be asked. But that doesn't mean there isn't an answer. And it doesn't seem that Reppert bothered looking for any answers. He only discusses one such, the "anomalous monism" of Donald Davidson, which belongs to the category of "nonreductive materialism." But what about reductive materialism? What about solutions that do not involve anomalous monism? In other words, what about all other metaphysical naturalists?[17] And, indeed, what about cognitive scientists? A great deal of work has been done on brain-state causation, especially in regard the production, recognition, and recording of the very pattern-data that (we shall see) figure so centrally here. Until Reppert addresses all this, his AfMC is at best unfinished and unproven.
Worse, on my naturalism, it is false (see my discussion of Propositions 3 and 6). On my theory, every meaningful proposition is the content of a virtual model or the content of an output of such a model. With regard to the question of possible but not actual propositions, I qualify my definition to say that actual propositions obtain from actual models, while potential propositions obtain from potential models. For I do not believe propositions "exist" anywhere besides human minds or as the products thereof. Yet there is an infinity of "potential" propositions that are not now and probably never will be actualized, just as there is an infinity of "constellations" that exist in the terrestrial star field. Even though we will never name all possible shapes that could be found by connecting the dots in the sky, nevertheless those shapes really are there, since they physically exist as a direct consequence of the physical existence and physical arrangement of the stars. There doesn't have to be some nonphysical Platonic "realm" where those shapes all exist. The physical facts alone are sufficient to establish the existence of that infinity of shapes—whether any mind notices them or not.
This relates to the issue of so-called Abstract Entities. Reppert rightly notes that "if physics is a closed system, then it seems impossible for abstract entities, even if they exist, to make any difference in how beliefs are caused" (54). I agree. But I follow Aristotle: I do not believe there are any such things as abstract "entities," only "abstractions," which are essentially just human labels for repeating or repeatable patterns in sensory or conceptual experience (a concept I develop in my book Sense and Goodness without God: A Defense of Metaphysical Naturalism). For example, we can say "triangularity" exists because of the physical fact that a shape with three sides is physically possible and physically manifest in many places, and the pattern of arrangement in question (the having of three sides) is the same in every one of those cases. All that is required for that to be true is the existence of places and sides, which are physical facts, not Platonic or supernatural ones. And the human brain (in fact, the brain of every higher animal) is physically wired to "detect" repeating patterns like that, and remember them, so it can detect where the pattern repeats itself, and take advantage of that special information. Humans, of course, can assign codewords for those repeating (or repeatable) patterns that their brains detect, and those words are called "abstracts." Reifying them, as Plato did, is a fallacy. But at the same time, my view is not antirealist, either, since I believe abstract words really do refer to real things: repeatable patterns. Whether these physical patterns are repeated in the physical universe outside our minds or only in our minds does not matter, since on my view our minds are a part of the physical universe.
With that background in place, my answer to the question Reppert poses is that the content of a mental state is literally and physically the content of a virtual model computation, which in turn produces a computational output that physically causes a subsequent computation to produce a certain output by providing the physical input for it, and so on. This much should be clear already. I can illuminate my position further by explaining how I disagree with Davidson (or at least Reppert's characterization—which I am inclined not to trust, given his mistreatment of the Churchlands):
(1) Reppert says Davidson holds that "mental states can have contents that do not correspond to anything in the material world (e.g. false beliefs)" (79). I suspect Davidson had in mind fictions here, not false beliefs, but I will address both. First, mental states are in the material world, so a mental state that has content that corresponds to another mental state corresponds to something in the material world. Unless we are talking about something literally just invented out of the blue by one single brain, it is probable that any mental state corresponds to at least one other. This is the case in fiction, for example: the lifespan of Yoda is a fictional characteristic of a fictional person. Though there is no Yoda and thus no Yoda lifespan, there is a fiction of a Yoda and that fiction has been related to a Yoda lifespan. The fiction was invented by one or more persons at some point, but since then has become a part of millions of minds and remains recorded in documents and physical records of all varieties. Thus there is a fact of the matter whether Yoda lived to around 800 years of age. It is not that there really is a Yoda who lived 800 years, but that there is a fiction of a Yoda who lived 800 years, and there is an accepted authority on the matter (those who invented and/or control the copyright to the character named "Yoda," and/or official "guidebooks" to the Star Wars universe, which were most likely written and/or approved by the same). To disagree whether Yoda lived so long is a debate over whose authority to follow in establishing the "official" Yoda lore. It is not a debate over the actual age of any real person.
This is the sort of thing philosophers usually have in mind when they discuss intentionality (as the context provided by Reppert suggests Davidson was doing). What is a thought about Yoda really about if there is no Yoda? Well, it is about a physically existing lore about a fictional character. And the existence of a fiction of a character is itself a physical reality. The intention of a Yoda proposition can and often does encompass certain assumptions or choices regarding which physically-existing authority "counts" as far as establishing what should be accepted as "true" about Yoda. For example, it is a physical fact that there are pornographic sex-stories involving Yoda—but one can still claim Yoda never had sex by appealing to an accepted authority who is mutually accepted as having the right to establish what shall be true about the fiction of Yoda. And so on. In every case, even with fiction, there is something that physically exists that thoughts of Yoda are "about," and per my analysis of intention, we choose the connection, and in so doing, physically create such a connection in our brain.
On the other hand, the question of false propositions is another matter altogether, since those are not fictions, but actual claims to reality. I already analyzed earlier how intention relates (or rather, does not relate) to the truth or falsehood of a proposition. In either case, a proposition is still about what we declare it to be about, regardless of whether it states something true or false about that thing, whatever it is. So it is not correct that false propositions "do not correspond to anything in the material world." It is correct that the entire content of such propositions does not so correspond, but that is not what is referred to by intention. What is referred to by "intention" is whether a proposition is hypothesized about a particular set of data or a particular system in the real world (which is hypothesized from that data). And that can be true even if the hypothesis itself is false. And even when the intentional object is a hypothesized reality that in fact doesn't exist, the hypothesized reality does exist as a model of the world in at least one person's brain, and therefore physically exists, albeit in a different form than the agent believes. Thus, no matter how you cut the cake, propositions are always about something that physically exists.
(2) Reppert says Davidson holds that "mental states" that possess intentionality "cannot be fitted into lawlike statements and therefore cannot be predicted or explained by causal laws" (79). I am not sure what Reppert expects here—many physical phenomena are too complex to be predictable or neatly defined by a fixed set of "lawlike statements," but that does not mean they cannot be explained by causal laws or events. On my view, a mental state cannot have propositional content without the physical presence in the brain of a model of the very pattern that proposition defines. Without that physical pattern in the computer of the brain, the brain would never produce any corresponding thought. Conversely, the fact that that physical pattern, rather than some other pattern, is in the computer of the brain, is precisely what causes the brain to run its computation in one direction rather than another. Since the pattern must physically exist for the thought (the "proposition") to exist, and since a physical pattern of brain activity obviously has a causal effect on the future course of that brain's physical activity—an effect that differs from that of another pattern in precisely the respect that matters here—it simply makes no sense to claim that naturalism entails "no event can cause another event in virtue of its propositional content." Even on my thoroughly physicalist view (on which I will have more to say below), that is the only way brain events (in the conscious sphere at least) can causally operate at all. So Reppert's Basic AfMC Premise is false, and hence so is the AfMC. [For more discussion, see in the secondary half of this critique: "Propositional Content" and "Zombies"]
4. The Argument from the Psychological Relevance of Logical Laws (AfPR)
The Basic AfPR Premise is "If naturalism is true, then logical laws do not exist or are irrelevant to the formation of beliefs" (82). As I have already explained (see my discussion of Propositions 4, 5, and 7), "logical laws" are propositions that describe truth-finding procedures, and the procedure by which we form beliefs is certainly not irrelevant (or nonphysical for that matter). Truth-finding procedures are obviously to be preferred to others, just as I noted in my discussion of the Causation Fallacy earlier. And clearly they must be carried through physically by any computer, whether a human brain or not. So, just as "rules of farming corn" exist, in the sense that there are procedures that result in successful corn farming and those procedures can be discovered and described, so also "rules of reason" exist, in the same sense that there are procedures that result in successful reasoning (i.e. reasoning that leads to true conclusions—or in the case if induction, reasoning that leads more often than not to true conclusions), and those procedures can in turn be discovered and described. What else needs to be explained?
There is no intelligible sense in which there can't be truth-finding procedures in a purely physical universe, yet that is what Reppert must show—he doesn't. Likewise, there is no reason to believe brains of a certain complexity can't discover those procedures (memetically, by learning, or genetically, by natural selection), yet that is what Reppert must also show—again, he doesn't. So Reppert does not establish the Basic AfPR Premise. Worse, on my naturalism, it is outright false. Therefore, the AfPR is false. Of course, one might try to argue it is improbable that, say, natural selection would have led to a brain developing such truth-finding procedures (or the ability to discover them through exploration of its environment), but we have already seen such an argument is implausible, and at any rate that would no longer be an AfR but an Argument from Design (AfD), and Reppert's book is not about the latter, but the former. Still, Reppert returns to the subject anyway in his last AfR, so I will have more to say about it then (see AfRF below).
Reppert does not seem to be aware of any of the computational theories of reasoning developed by cognitive scientists and followed up by naturalist philosophers—which is strange considering his fondness for quoting the Churchlands, among the most popular advocates of just such a thing. Thus, when he says logical laws "are not physical laws" (81) he is really missing the boat, betraying the fact that he hasn't done his homework. For logical laws are just like physical laws, because physical laws describe the way the universe works, and logical laws describe the way reason works—or, to avoid the appearance of begging the question, logical laws describe the way a truth-finding machine works, in the very same way the laws of aerodynamics describe the way a flying machine works, or the laws of ballistics describe the way guns shoot their targets. The only difference between logical laws and physical laws is the fact that physical laws describe physics and logical laws describe logic. But that is a difference both trivial and obvious.
Reppert thinks there are other strange differences, but he doesn't think them through. For example, he says logical laws are unlike physical laws in that the former "pertain across possible worlds, including worlds with no physical objects whatsoever" (81; cf. 94). But that is again just the same trivial difference, that physical laws, not logical laws, describe physics. The reason logical laws pertain to "possible worlds" is the very fact that the sphere of possibility entailed by such a phrase is the sphere of imagination capable of being explored by the virtual model computations of our brain (the assembly and reassembly of the elements of experience). For a world (or system or object within a world) to be "possible" is literally to be capable of simulation in our brain (or in any adjunct to our brain that extends its mental power—like a computer, hypothetical or real). Since reason is a function performed on computed data, especially but not only that category of computed data defined by virtual models, obviously the rules of reason will by definition describe what is applicable to everything that can potentially be computed. It is no accident that Gödel's Theorem connected with work in computation: he proved that the realm of the possible excluded certain things precisely because those things could never be computed. The limits of computation literally are the limits of logic, because computation itself literally is logic (or "a" logic—as there are many types of computation, there are many logics).
Missing all this, Reppert goes on to declare that "if one accepts the laws of logic, as one must if one claims to have rationally inferred one belief from another" (emphasis added) "then one must accept some nonphysical, nonspatial and nontemporal reality" rather like Plato suggested (81). Note how close Reppert is to getting it—but just when you think he has it, he puts the cart before the horse, then observes that the whole caboose won't go, and from that concludes it can't go, without some wizard to cast a spell to levitate the cart so it can drag the horse along where it needs to go. If you think that is a silly way to respond to an inverted horse-and-cart, then you will agree Reppert's approach to logical laws is silly, too. The reason one must accept the laws of logic to rationally infer anything is the very same reason one must accept the laws of aerodynamics to fly. Surely Reppert would not conclude that we need some sort of supernatural powers and beings to explain why we need to follow the laws of aerodynamics to fly. The reason we need them is that it is physically impossible to fly any other way, and the only way flight is physically possible is exactly the way described by those laws. All you need for that to be true is a physical universe that is a certain way. Of Plato's hypothesis we have no need.
Yet one could just as easily say that the laws of aerodynamics are "nonphysical, nonspatial and nontemporal." Or rather, one can just as wrongly say so. For the laws of aerodynamics do not exist but for the physical objects and relations that physically interact as they do. Thus, there is no sense in which the behavior of physical objects, or their existence, or their interaction or relation, is "nonphysical." The same goes for space and time: without space and time, there would be no aerodynamics, and yet we can use the laws of aerodynamics to describe possible flying machines that never have and never will exist. For the laws of aerodynamics apply to (they describe) all physical worlds that are relevantly similar (i.e. that have the same physical attributes that entail, and are entailed by, those laws), including worlds that have flying machines in them that do not exist in this (we suppose actual) world. The same is true of logic, though even fewer physical attributes are necessary for them (e.g. the mere physical fact of the existence of distinctions and causal and ontological consistency is sufficient to establish the law of non-contradiction—see below, as well as my later discussion of the Ontology of Logic).
Now, it is true that we can compute simulated worlds that lack space, time, and physical objects. But the laws of logic concern only what computation can and cannot do, regardless of how computation is manifested or brought about. Maybe it is possible for computation itself to exist without space, time, and physical objects—I doubt it, but I don't trouble myself with trying to answer such a question, because it is of no relevance to me, who literally am a physical computer in space-time. Even if computers can exist in other nonphysical worlds, that does not entail that computers can't exist in purely physical worlds. And the question at issue is solely whether computation can exist in a purely physical world. Thus, when I say computation only exists in this world as a consequence of complex physical machines functioning in space-time, I am not saying this is the only way it can be done, but simply that this is the only way we have ever seen it done, which means it is probably the only way it can be done (at least "around here").
It is here that we must avoid the Causation Fallacy I described earlier. Just because computation can be, and in our world actually is, carried out by physical machines operating in space-time, it does not follow that such computers cannot perform truth-finding operations, or that there are no particular procedures of computation that are more truth-finding than others, or that there are none that are most capable of such an output. To the contrary, it is precisely because computers exist that makes it possible for them to perform truth-finding procedures rather than others, and it is precisely because of this that it is possible to describe such procedures propositionally. And that is what "logical laws" are. There is thus no need of anything nonphysical or outside space and time. Computers, whose truth-finding operations logical laws describe, are physical and exist in space and time. Yet the existence of computers that perform truth-finding operations is all that is necessary for logical laws to exist. Exactly the same as for the laws of aerodynamics.
As to how we can come to discover the laws of logic, that is no different than how we came to discover the laws of aerodynamics, or the laws of ballistics. There is no mystery at all in any of these cases. The latter is a particularly close analogy: our brains naturally evolved an intuitive albeit imperfect understanding of the laws of ballistics. When we throw or catch a ball, our brains compute its trajectory with amazing accuracy. Our brains can also improve this computational ability through experience, by trial and error. But even before we do that, we are already born with a ballistics computer in our head (as are many other animals). It isn't a superb computer—but that's because it developed blindly by natural selection, and not by design. It needs perfecting, and each individual can perfect it through experience. But all this goes on without any conscious awareness of what the computer is doing.
Then we came to discover how to precisely describe the operation of such a computer, when we discovered the laws of ballistics themselves (by observing and testing and so on), and defined them (using languages, like mathematics, specially adapted to such purposes). Later, with this knowledge in hand, we were able to build nearly flawless ballistics computers superior to our own. But even without that technology we could use our own general-purpose computer—the cerebral cortex—to run a nearly flawless ballistics computation by running a program called "mathematics." Our cerebral cortex wasn't "built" for that, so it is very inefficient when used that way—it takes a lot of time and can make mistakes every now and then—but it can still be used that way, because the computational architecture required is exactly the same as that which our brains developed to communicate, and to reason their way out of an infinite variety of problems, and into an infinite variety of advantageous solutions.
So simple the solution is. It is perhaps not surprising, then, that the only form of naturalism Reppert attacks on this point is that which adopts logical antirealism. We are left in the dark whether the AfPR even applies at all to logical realists in the naturalist community. So yet again, Reppert claims his argument applies to all kinds of naturalism, when in fact he only gives evidence against one variety—and a relatively unpopular one at that. He never says a word about any of the naturalists who advocate logical realism—like, say, me. And he can't claim to have not known I was a logical realist—I've made my views quite clear to him in correspondence. But never mind that. For he never even names a single soul. Or rather, he names one, but curiously omits to mention how that famous fellow solved the problem.
That man is Aristotle. Reppert cites Metaphysics 4.4 (= 1005b-1006d) against the plausibility of logical antirealism (81). But it is strange that Reppert didn't do what he ought to have done, and present Aristotle's explanation of logical laws, for Reppert at the very least must refute that before he can claim physicalism is defeated by the AfPR—since Aristotle's solution posits nothing not already accepted by all physicalists. But that would only be the tip of the iceberg. There are dozens of modern naturalists that defend some form of logical realism, and Reppert must refute them all to establish the Basic AfPR Premise. But as I said, he doesn't even name them, much less refute them.
Here is what Aristotle has to say about the fundamental principles of logic (those from which all other principles derive), especially the Law of Non-Contradiction:
The starting-point for all such discussions is not the claim that one should state that something is or is not so (because this might be supposed to be a begging of the question), but that he should say [i.e. be able to say] something significant both to himself and to another (this is essential if any argument is to follow; for otherwise such a person cannot reason either with himself or with another); and if this is granted, demonstration will be possible, for there will be something already defined. (Metaphysics 1006a)
He goes on to explain that words have definite meanings assigned by human convention, and for that very reason words cannot also mean what they by definition deny (ibid. 1006a-1007a). Thus, for Aristotle, logical laws derive necessarily and automatically from the existence of communication (defining terms and reasoning with others) and computation (reasoning with oneself). The moment you have those, in any possible universe, you will always have logical laws. It can never be any other way. This is exactly what I argue above and elsewhere. And since one does not need anything more than physics to have communication and computation, you do not need anything more to have logical laws.
Extending the point to physical reality, Aristotle argues:
Again, if all contradictory predications of the same subject at the same time are true, clearly all things will be one. For if it is equally possible either to affirm or deny anything of anything, the same thing will be a trireme and a wall and a man, which is what necessarily follows for those who hold the theory of Protagoras. For if anyone thinks that a man is not a trireme, he is clearly not a trireme [i.e. in their conception], but he also is a trireme if the contradictory statement is true. So the result is the dictum of Anaxagoras, "all things are mixed together," so that nothing truly exists. (Metaphysics 1007b)
Aristotle goes on to explain that a posit asserts that something exists, while a negation asserts that it does not, so that to assert both is to declare, literally, nothing (ibid. 1007b-1008a). That is, a self-contradiction communicates nothing, and represents nothing even in the mind of one who wishes to declare it. Thus, it cannot correspond to anything real except the null set. This follows as a consequence of language alone. But as Aristotle observes, this also follows physically: for if everything is true, then there is only one thing—in other words, there is no difference between one object and another. In fact, there are no objects (exactly as Protagoras concluded). For to be an object requires distinction from something else, and distinction literally is a non-contradiction. That is, a distinction is the literal and physical opposite of a contradiction. It therefore follows that in any universe where distinct objects and properties exist, no self-contradictory propositions will be true for that universe (see ibid. 1008b for an example of Aristotle's extension of the point to practical physical behavior).
This is also the case (for essentially the same reason) for the observation that in any universe where three spacial dimensions exist without curvature, no parallel lines will ever meet. The axiom (in this case the Euclidean axiom of parallels) describes a physical fact of the universe proposed. It is not some Platonic form or some "law" beyond space and time—it is a physical property of that universe, such that it would be impossible for that universe ever to exist and for the axiom of parallels not to be true (as part of a description of that universe). No mysterious logical relation is needed for this to be true: just the physical facts themselves. So also for the law of non-contradiction—that "law" is just like any other physical law: it describes any universe that contains distinctions (and causal and ontological consistency), which is (I suspect) every universe except the null set, since we cannot conceive of (compute) any other universe without positing at least one consistent distinction. This, again, is not because of some mysterious logical superlaw, but because the physical facts of any universe we care to compute are just so.
In short, the laws of logic literally are the (potential or actual) physical properties of every (potential or actual) universe that they describe. If there is any possible universe that the laws of logic do not physically describe, then, obviously, logic would not apply to it. So far man has not been able to imagine (simulate) any such universe, except a nullverse. True, this could be because of some limitation inherent in all computation (a la Gödel). But that would be irrelevant really, since we obviously don't live in such a universe, and the discovery of such a possibility would be no more devastating to logic than the discovery of non-Euclidean geometry was to geometry. After all, in our physical universe, parallel lines can meet. Yet geometry is not overthrown.
If only Reppert had read past the short little section of Aristotle that he apparently glanced at. Had he done so, he would have realized there is a powerful naturalist, realist theory of logic that he doesn't even mention, much less rebut. And lest he think Aristotle too vague and unclear, his arguments have been much refined and advanced upon by numerous philosophers since. Reppert need only do the research required of him to find it. Until he does so, and actually refutes it all, he cannot claim the AfPR has any merit against all forms of naturalism. And if he wants to be lazy, he can just stick with mine: that logical laws are simply propositions that describe truth-finding computational procedures.
As Reppert himself says, "Part of what it means to say anything is to imply that the contradictory is false" (82). Indeed, that is too wishy-washy: the fact is that what it means to say anything is literally at the same time to say (not imply, but assert) that the contradictory is false. Reppert sees this. So why doesn't he connect the dots? If, as even he admits, "language simply does not function" (82) without following logic, isn't it then obvious where logic comes from? Why do we need something more than language, if language already comes with logic included? And though he worries that if logic, like language, is merely a "convention," then we could have different conventions, he misses the obvious: that logic, like language, has a specific goal—to get at the truth. Thus, we can't adopt "just any" conventions for logic—we must discover those conventions that best get at the truth, just as we must discover the best ways to grow corn or hit targets with guns. By the same token, the aim of language is communication. And though any language is possible, all languages must follow the same basic rules for communication to be possible—and that is simply a physical fact of the universe. Nothing else need be the case for that to be so. And since reason is essentially a form of computation by communicating (speaking) with oneself, and has the goal of truth-finding, and those procedures that are most truth-finding are most desirable for obtaining that goal, we need look no further for where the procedures of reasoning come from, or what causal role they play in our brain's physical computations.
5. The Argument from the Unity of Consciousness in Rational Inference (AfUC)
The Basic AfUC Premise is "If naturalism is true, then there is no single metaphysically unified entity that accepts the premises, perceives the logical connection between them and draws the conclusion" (84). Now, this isn't really an AfR. As I will show, it is actually just a disguised Argument from Consciousness (AfC), and Reppert does not present any of the evidence or argument or interaction with leading naturalist philosophers and cognitive scientists that would be required to carry off an AfC. As I noted already earlier, unified consciousness is not essential to any truth-finding computation (see my discussion of Proposition 8). In other words, it is consciousness itself that Reppert presents as a problem here, and not the carrying out of truth-finding procedures, yet there is nothing about this problem that is unique to or derives from reason, any more than all other forms of perception and conscious thought. Still, I will address this issue anyway, to correct many of Reppert's misunderstandings—or, maybe, his ignorance of what is, after all, standard introductory textbook stuff as far as cognitive science goes. But note that much further detail (and qualification) will be provided in the secondary half of this critique (cf. Theory of Mind).
Reppert complains that "if physicalism is true, then each" moment of awareness in a process of reasoning "is a different brain process," so he asks "what ties them all together in an inference?" (83). Well, for starters, what ties together the synchronization of visual and auditory phenomena? We know how to fool the brain systems responsible for this, and can identify exactly where in the brain synchronic stitching of disparate sensory phenomena is controlled. We have also identified synchronizing rhythms and brain systems responsible for generating coherence across the whole spectrum of conscious experience, and can greatly interfere with the experience of consciousness by interfering with these systems or the synchronizing electric signals they generate and regulate. A great deal more could be said about this subject, and one can get a decent background in it by reading any introductory college textbook on neurophysiology or cognitive science. So why does Reppert act like he has never heard of any of this work? Can it really be that Reppert is willing to make global assertions about brain function without having read anything on actual contemporary brain science? I certainly hope not. But I cannot otherwise account for his failure to address the neurophysical systems responsible for synchronic brain function, or any of the other facts we know that pertain directly to this and many other issues Reppert raises.
This is not to say that the problem of synchronic stitching has been solved.[18] There is a reason William Hasker is skeptical of our success here, but he is the only author whom Reppert cites on theories of consciousness—despite the fact that he is not a naturalist, but a Christian (author of the Christian treatise Providence, Evil and the Openness of God (2004)). If Reppert had given naturalism a fairer shake, he would see that Hasker's analysis disguises the fact that a great deal of progress has been made toward understanding synchrony, unification, and the peculiarities of human experience. Instead, Reppert's open question ("what ties it all together?") betrays a willful or inexcusable ignorance of this progress or its relevance to answering that very question.
For example, when Reppert says that "it makes no sense to 'parcel out' a complex awareness to parts that lack a comprehensive awareness" (83) he really isn't taking brain science seriously. For the exact opposite is true: it only makes sense to parcel out a complex function to multiple parts. Indeed, I cannot personally conceive of any other way any complex function could be performed, outside of magic. For example, imagine Reppert saying "it makes no sense to 'parcel out' a complex digestive system to parts that lack a comprehensive digestive capability." That really would be a silly thing to say. Obviously a complex digestive system can only exist by doing exactly that: parceling out different functions to different organs. This in no way prevents food from being digested. By the same token, that a brain produces a function called "consciousness" by parceling out all the various needed functions to different organs (brain systems) in no way prevents consciousness from being produced. Indeed, I cannot imagine any other way such a complex function could be produced—except, again, by magic. Which is basically, of course, what Reppert wants to conclude.
But bad news for Reppert: we have empirical proof of the fact that consciousness is a post hoc product of disparate functions working in synchrony. It has long been well-known, and has been demonstrated in numerous experiments, that what we call "conscious awareness" always follows by a few hundred milliseconds every single operation involved in that awareness. For example, we have proven that your brain has already made a decision—say, to raise your hand—well before you yourself become aware of making the choice to raise your hand. Now, many use this data to argue against the existence of free will, but they jump the gun a bit, mistakenly supposing that being aware of making a choice is what defines a will. But a will is not defined by awareness, but actually willing, and thus the human will consists in the actual decisions made, regardless of when we become aware of them (and regardless of the fact that this awareness, like any other, can sometimes be mistaken). And throughout all this the "we" in question is not the "awareness" of a "we" but the actual entity (the brain and its functions) of which we are aware, since it is the actual thing detected that is really us, not the awareness of it. Thus, that we only become aware of what we have thought and done well after we have already thought and done it does not mean we didn't think and do it. But it does mean that conscious awareness is itself a perceptual process that follows all the other processes of which it is aware (like reasoning) and therefore it is not essential to reasoning or any of those other processes.
Conscious awareness is, however, very useful, because it can provide feedback to the rest of the brain through top-down causation. Though military units (or, to draw on Reppert's own analogy, a class full of students) can function rationally on their own, put a machine at the top that can pool all the information from all the units (or students), and send that information back down to every individual, each one extracting from it the information it needs (or is designed to handle), and you will have a far more successful team. This is all the more so when the machine at the top can not only redistribute data globally, but can itself identify patterns in that data that no single unit (or student) could see on its own (like, for example, the connection between a desire, a means, and a goal) and transmit that (entirely new) data back down as well. It is this latter function, performed by the cerebral cortex (the "machine at the top"), that is especially to credit for things we most prize about consciousness: the ability to carry off long-term planning, to construct complex systems of ideas, to construct a coherent identity, and, most of all, predict the thoughts and behaviors of others through the ability to model (and also, as a result, empathize with) their consciousness, which is doing all the same things. Now, this machine would be useless if not for the separate units feeding it information, and receiving its data and commands in turn.
So it is thus obvious that you cannot have consciousness without the parceling out of functions across several distinct specialized organs. An eye cannot hear, nor an ear see. And so, too, the primary visual cortex is not very adept at emulating the function of the primary auditory cortex. Human brains are flexible, and can reprogram themselves. But they function best when divided into specialized systems, each a master at its own domain. Hence we have found that entirely different parts of the brain recognize faces, assess distances, store names of objects, store names of people, compute color information, compute shape information, and so on. This is indisputable scientific fact. So there is no way Reppert can pretend that this isn't how the brain works. It clearly does. Likewise, though the cerebral cortex is the brain system that produces consciousness, it can only produce it by stitching together and developing a series of "perception" events from the data of all the other systems (visual, auditory, etc.). Take away those systems, and you take away all the data needed to generate conscious awareness.
Hence came my answer to Reppert earlier: Yes, we already know in outline what goes into physically unifying consciousness, so this is no great problem for physicalists; but No, that doesn't really have anything to do with reason as a truth-finding computational procedure. Just as sight and sound are both processed in different parts of the brain, yet the data is organized and "perceived" as a coherent field of awareness by the cerebral cortex (with the aid of several other pieces of the brain), so also any process of "reasoning" can be carried out by different parts of the brain, yet the data can still be organized and perceived, and thus related, by the cerebral cortex, which in turn can cause, in a top-down way, those same systems to move on to the next step of reasoning, and so on, back and forth.
So an analogy more apt than Reppert's would be: the students all pass their test answers into a machine that identifies all the correct answers and spits out only the correct ones back down to all the students, who can then all see they aced the test, even though each one only worked on a part of it. Of course, the analogy breaks down precisely because it is using conscious agents in the place of unconscious ones. But the point is the same: just as a collection of cells can organize and cooperate into a body that can walk on two feet—even though no one of those cells can walk at all or even has legs, much less the other needed organs, like hearts and lungs—so also can a collection of brain systems organize and cooperate into a mind that can think. And it does this by producing the virtual appearance of a singularity of consciousness, just as it produces the mere appearance that unified patches of color exist—when in fact only streams of various distinct particles exist.
So Reppert's assumption that a collection cannot produce a unified function simply does not hold up in the light of the facts of cognitive science. But his other assumption, that the brain must parcel out the steps of reasoning, is also ungrounded in any actual science. Though it is true that different parts of the brain contribute different things to any actual stream of thought, rational or otherwise, the synchronic stitching and higher perception of internal brain function that takes place in the cerebral cortex actually generates simultaneity, not sequential steps of reasoning. Though we can walk through a syllogism step by step if we want to, this isn't really what is going in our brain when, for example, we "see" that a conclusion follows from a major and minor premise. To the contrary, we see the connection immediately. For example, when we see a stop sign, several systems in the brain cooperate to generate a perceptual field—one system recognizes its shape, another its color, and so on, and the synchronizing signal produced by another system relates these facts to other areas of the brain at the same time (for every part of the brain is physically connected to ever other), which identify that the combined pattern of these two things indicates a stop sign, and so on. But this all happens at the same time.
Logical deduction is a form of analysis. When we see a stop sign, color and shape unified, we see it all at once. We perceive not disparate elements in sequence—first a color, then a shape, etc.—but our brain physically regulates synchronization and perception of relational patterns (such as the pattern of a color spanning a space within a shape—and we know where in the visual cortex this unification of visual data occurs). We can then pick apart what we see, and examine the shape apart from the color, then the color apart from the shape, and so on. But all the while, we have it all in view: the perception of both is simultaneous. This is exactly what we do when we perform acts of formal deduction: we see a picture all at once, the picture described (and thus physically caused to be constructed and "perceived" in our brain) by the major and minor premises, and then, seeing it all at once, pick apart the relevant elements one by one. In a simple syllogism, this means only one element, though most human reasoning is more complex than that. But in the easy case, when we see that a conclusion follows from the premises, this is exactly the same thing as seeing that a stop sign is both red and hexagonal and "therefore" a stop sign: the perception of everything (the two premises and the conclusion) is seen all at once. Thus, the brain does not reason "step by step" as Reppert claims. It reasons holistically. It draws a picture and then examines, analyzes, that picture, which stays in view the whole while (as long as the brain continues to devote attentional resources to it).
Stepwise reasoning takes place on a larger scale: when we move, for example, from one observation, one syllogism, to another. The conclusion of one syllogism then becomes the premise in another. We then assemble a new picture, depending on what the other, fourth premise is, and again see all at once what follows from "running" that virtual model as instructed (whether the instructions come from ourselves—reasoning with ourselves—or others). Thus, even when stepwise reasoning is engaged, it is still not what Reppert claims—it is not the brain moving sequentially from step to step within a single syllogism, but from one syllogism to another, every one linked into the chain by another simultaneous experience.
All that Reppert can do is deny that a physical system could possibly produce the simultaneity of a coherent field of awareness definitive of consciousness (and this is what he does, by quoting a book review (!) by Goetz). But doing so would no longer have any relation to reason. For we already showed that such simultaneity is not a necessary feature of any reasoning process. It is how humans do it. But it can be done by a stupid Turing Machine, too. Rather, such an argument (from the oddness of our experience of a unified consciousness) would be an AfC, not an AfR, because such a claim would impugn all conscious perception, not just that related to reason. Otherwise, if you accept a physicalist account of conscious perception at all, then you can have no ground to object to the extension of this to reasoning. [For more discussion, see in the secondary half of this critique: Introducing the Question of Computers and Computation and Perception, and then Computation, Perception, and Propositional Content]
6. The Argument from the Reliability of Our Rational Faculties (AfRF)
The Basic AfRF Premise is "If naturalism is true, then we should expect our faculties not to be reliable indicators of the nonapparent character of the world" (85). As I noted earlier, the question here is whether a purely natural universe can produce the "reliable reason" that we observe and that Reppert rightly accepts as an established fact (see my discussion of Proposition 9). He is essentially adapting Plantinga's Evolutionary Argument Against Naturalism into the form of an AfR. I have already covered the issue in my discussions above of the AfT and the AfPR (Reppert's arguments #2 and #4), and elsewhere.[19] I will also revisit the issue later (see Reliablism and We Should Attack Rocks?).
In contrast, it must be noted that Reppert doesn't try very hard to establish the Basic AfRF Premise as true. He presents no actual evidence in its favor, just a single assertion resting on a single uncritical supposition. He does not interact with any of the literature criticizing Plantinga's deployment of the very same argument, and indeed Reppert gives the impression that there is none, which is certainly unfair to his readers—and makes this section of his book rather useless to anyone who wants to critically examine the issue. As I pointed out already, that is a common failing in this book. Reppert ought to have done his homework here, but didn't. Yet such background would have made his book a hundred times more useful. And if the premises of his six AfR's are true, addressing such background would have made his book a hundred times more persuasive as well.
The single assertion on which Reppert rests the entire foundation of his AfRF is that "we could effectively go through our daily life without knowing, or needing to know, that physical reality has a molecular and an atomic structure" (85), which is true, but not relevant to the question at hand, which is, as Reppert himself puts it, "would naturalistic evolution give us mostly true beliefs, or merely just those falsehoods that are useful for survival?" (84-85). I have answered that question above already. His assertion is as fallacious a basis for the Basic AfRF Premise as the assertion that we (as animals) could survive and flourish without an opposable thumb (which is true), therefore nature would never have selected them (which is not true). Or to draw an even closer analogy, we (as animals) could survive and flourish without being able to play complex musical instruments (which is true), the ability to play complex musical instruments follows necessarily from the possession of opposable thumbs (which is also true), therefore nature would never have selected opposable thumbs (which is not true). My point is: Reppert needs to fill in a missing premise here. Otherwise, his assertion does not support his argument.
The "uncritical supposition" that Reppert uses to try and fill in that blank is again just a mere assertion, backed by no evidence: that "natural selection would favor the development of reliable cognitive and rational abilities only insofar as those aptitudes helped protohumans cope with the challenges of their environment" but "there is no reason to believe that we should trust our reasoning abilities beyond that original 'coping' function" (85), or in other words "what is required for survival is effective response to the environment, not accurate knowledge of that environment" (100). This is faulty reasoning in two crucial respects:
First, one should immediately ask: "How does he know?" By his same reasoning, peacocks should not have colorful and burdensome feathers. But they do. And we can explain why they do on purely natural evolutionary principles. Thus, there is more to evolution than merely "coping," which means Reppert's supporting supposition is uncritically adopted. It is in fact scientifically false. What gets selected by evolutionary process is whatever aids differential reproductive success. Advanced abilities to "cope" with an environment do serve