Maverick Philosopher

But consider an analogy. Suppose you explain to a person that the natural number series is infinite, and that there is no largest natural number since for every n, there is n + 1. The person seems to understand, but then objects when you say that it is impossible that there be a largest natural number due to the very nature of the natural number series. Your use of 'impossible' sticks in the guy's craw. He tilts Leftward, you see, and he thinks, quite confusedly, that anything's possible. He doesn't like it when people invoke natures and impossibilities. That's too rigid and static for his taste. So he says,

Before long, we will have supercomputers so fast that they can reach the end of the natural number series. Who are you to say that that it impossible? All sorts of things have been pronounced impossible that are now actual. Given the enormous strides being made in computer technology, it is just a matter of time before a computer will reach the end of the natural number series.

Now the rank absurdity of this is (I hope!) self-evident. The fastest possible computer will operate at a finite speed: the speed of light (186, 282 mi/sec) is a speed faster than which no signal can travel. Combine your nanotechnology with cryotechnology, get down near absolute zero, there is still an upper bound on computing speed.

Now here is the analogy. Just as no computer no matter how fast will ever reach the end of the natural number series, no amount of brain science will ever find consciouness in the brain, or explain how consciousness arises from the brain, or how it could arise from the brain.

No doubt some of you will protest that the two situations are disanalogous. But then the burden is on you to explain exactly why they are.

Though we knew the connections of every tickling thread of every single axon and dendrite in every species that ever existed, together with all its neurotransmitters and how they varied in its billions of synapses of every brain that ever existed, we could still never -- not ever -- from a knowledge of the brain alone know if that brain contained a consciousness like our own. (p. 18, emphasis in original)

I think this is an extremely important point, the beginning of wisdom in the philosophy of mind, and a point not appreciated by some members of my esteemed Commenter Corps. In sum: Even if we knew everything about brains, such knowledge would provide no basis whatsoever to infer anything at all about either the existence or the nature of consciousness. I am pleased to see that Owen Flanagan is also quite clear about this:

Imagine an utterly complete explanation of the brain framed in the languages of physics, chemistry, and biochemistry. What has one learned about mental function? The answer is nothing, unless one's neuroscientific inquiry was guided in the first place by the attempt to map certain functions onto the brain. (Consciousness Reconsidered, p. 12)

I seem to recall one commenter who made the surprising response: "But a completed neuroscience would provide knowledge about consciousness, otherwise it wouldn't be completed." This response shows a total misunderstanding of the problem. It is not as if we don't know enough, and just need to know more in order to solve the problem of consciousness. The problem is that there is an unbridgeable gap between our objective, 3rd-person knowledge of such physical things as brains and conscious states.

Here is a way of making the situation graphic. Suppose you have a live test subject, Sally. She is, however, wholly uncooperative and will not report on her conscious experiences as a team of neuroscientists manipulate her brain states. Even if those neuroscientists have a complete physical, chemical biochemical, electrochemical, etc. understanding of Sally's brain right down to the number of neurons, the voltage differences across every synaptic junction, etc., they will not be able to map conscious states onto brain states. But if Sally starts talking, then progress can be made.

The point is that a conscious being, in conscious states, is a presupposition for any brain research. The brain, by itself, is just a physical thing. Complete knowledge of it entails nothing about consciousness.

These subjective qualities can be features of sensations, but they need not be. Smashing my knee against a table leg elicits a certain unpleasant sensation. The felt quality of that sensation is an example of a conscious datum in the relevant sense. But so is the shimmering quality of a magnificent Saguaro cactus standing sentinel on a distant ridgeline as viewed in the lambent light of the desert Southwest. Qualia, then, can be associated with intentional objects and not merely with non-intentional states like sensations. Pressing some Husserlian jargon into service, we might distinguish between noematic qualia and hyletic qualia.

But the main question is this: What good is consciousness from an evolutionary perspective? Owen Flanagan (Consciousness Reconsidered, MIT 1992, p. 42) has this to say:

What function might sensory or perceptual consciousness serve? Such consciousness could enable an organism to be sensitive to stimulus saliencies relevant to its suvival and to coordinate its goals with these saliencies. Informational sensitivity without experiential sensitivity (of the sort an unconscious robot might have) could conceivably serve the same function. Indeed, it often does. But the special vivacity of perceptual experience might enable quicker, more reliable, and more functional responses than a less robustly phenomenological system, and these might have resulted in small selection pressures in favor of becoming a subject of experience. At least this is one possible explanation for why Mother Nature would have selected a mind with capacities for robust phenomenological feel in the sensory modalities. It is good that reptiles are sensitive detectors of earthquakes. It enables them to get above ground before disaster hits. It is good that we feel pain. It keeps us from being burned, cut, and maimed. . . . Like photoreceptor cells designed for vision and wings for flight, the capacity to experience pleasure and pain is a design solution that Mother Nature has often used in different lineages of locomoting organisms.

I judge this to be a complete failure as an explanation of why consciousness has evolved. All the jobs Flanagan mentions might have been done 'in the dark' by unconscious processing. Yes, pain is good insofar as it keeps us from being burned, cut, and maimed. But pain in this sense is just the sum-total of physical events that play a certain causal role, that of causing the organism to withdraw or protect a part of its body on the occasion of a certain input. Think of a robotic arm equipped with heat sensors. It is designed to retract when the object it touches is at a certain temperature or above. The arm can function perfectly well without feeling anything.

Let's not forget that words like 'pain' lead a double life. 'Pain' is used to refer both to physical events and to their phenomenal manifestation. Phenomenal pain, far from being good, is evil, a form of natural evil. Insofar as it is (instrumentally) good, pain is not felt or phenomenal pain but the physical events that may or may not manifest themselves at the level of consciousness.

Consciousness is real -- eliminativism is for lunatics -- and so consciousness must be explained. But an evolutionary explanation is inadequate. Such an explanation must specify a survival function consciousness serves that could not be served without it. But what could that be? Thus I think David Chalmers (The Conscious Mind, Oxford 1996, p. 120) is on the right track:

The process of natural selection cannot distinguish between me and my zombie twin. Evolution selects properties according to their functional role, and my zombie twin performs all the functions that I perform just as well as I do; in particular he leaves around just as many copies of his genes. It follows that evolution alone cannot explain why conscious creatures rather than zombies evolved.

Chalmers also points out that

. . . the real problem with consciousness is to explain the principles in virtue of which consciousness arises from physical systems. Presumably these principles -- whether they are conceptual truths, metaphysical necessitires, or natural laws -- are constant over space-time: If a physical replica of me had popped into existence a million years ago, it would have been just as conscious as I am. The connecting principles themselves are therefore independent of the evolutionary process. While evolution can be very useful in explaining why particular physical systems have evolved, it is irrelevant to the explanation of the bridging principles in virtue of which some of these systems are conscious. (p. 121)

This strikes me as an extremely important point. If we think of evolutionary genesis as proceeding 'horizontally,' then the arisal of consciousness can be thought of as 'vertical.' If we want to explain how consciousness arises from its physical substratum, it is simply irrelevant to be given an explanation of how certain traits were selected for. An evolutionary account might explain 'horizontally' how an organism became sufficiently complex to host consciousness, but such an account would do nothing to explain how consciousness arose 'vertically' from the organism.

A fourth reason is that, unlike most other theories of being qua being, physicalism is meant to be criticizable by way of observational testing. According to contemporary physicalists, the principles of physicalism are to be treated as high-level empirical hypotheses or generalizations.

What Post is saying, then, is that the metaphysical proposition

1. To be is to be physical

is an empirical generalization supported by natural science and open to disconfirmation by future experience. Three objections immediately come to mind.

Objection One

The gist of my first objection is that (1) cannot be an empirical generalization. Empirical generalizations, if true, are contingently true. So if (1) is an empirical generalization, then (1) is contingently true. But then it can't be the case that to be is to be physical.

Why not? Well, (1) asserts an identity between the 'property' of being (existence) and the 'property' of physicality. This identity entails the necessary equivalence

2. Necessarily, for any x, x exists iff x is physical.

(One cannot validly move from equivalence to identity, but one can validy infer an equivalence from an identity.)

The upshot is that (1) is both contingently true (because it is an empirical generalization) and not contingently true (because it entails a necessary truth). But this is a contradiction, so (1) is not an empirical generalization.

Once one appreciates this, one sees that physicalism cannot be supported by natural science. In general, metaphysical propositions about being qua being cannot be supported or refuted by naturalistic methods. Natural science cannot take the place of first philosophy.

But couldn't (1) be taken to assert the contingent identity of existence and physicality? I don't see how. Indeed, I have no idea what that could mean. If two individuals are identical, then that is necessarily the case. Contrapositively, if two individuals are possibly distinct, then they are distinct. Similarly, if two properties are possibly distinct, as they would be if they were only contingently identical, then they are distinct. Consider a possible world in which something exists that is not physical, the number 9 say, or perhaps some set of physical objects. In that world existence and physicality are distinct properties. But if they are distinct in one possible world, then they are distinct in all possible worlds, including the actual world.

Second Objection

My second objection is that (1), if true, supplies itself with a counterexample, and thus refutes itself. (1) expresses a proposition, call it P. (I take it to be self-evident that a proposition must not be confused with its physical embodiment whether it be marks on a page or pixels on a monitor.) So if (1) is true, then the proposition P expressed by (1) is physical. But there is no tenable theory of propositions according to which propositions are physical entities.

Frege's Gedanken, for example, despite their name, are Platonic entities and therefore nonphysical. The same goes for Bolzano's Saetze an sich. Suppose you say that propositions are not Platonic entities but exist only as the accusatives of judging minds. Still, such accusatives cannot be intelligibly viewed as a physical entities. They are senses, even if they cannot exist in splendid Platonic independence. Less plausibly, a proposition might be construed as some sort of set-theoretical construction, whether a set of utterance events or a set of possible worlds. But even these far-fetched theories don't help since sets are abstract entities, hence nonphysical.

Propositions, then, cannot be physical. So (1), whether true or false, expresses a proposition, a nonphysical entitiy. Therefore (1) is false: the proposition it expresses is its own counterexample.

Third Objection

My third objection is a circularity objection: (1) is damagingly circular. To see this, ask yourself whether Pegasus is a counterexample to (1). Pegasus is a winged horse. So Pegasus is a physical item. After all, a horse is a physical item, and to add physical appendages to a physical item does not alter its physicality. So Pegasus appears to be a counterexample to (1): Peagasus is physical, but does not exist. To block this and like counterexamples, one must construe (1) as short for

3. To exist = to be physical and exist.

On this construal, (1) is true but circular. This shows that existence cannot be identified with the categorial property of being physical. Indeed, it shows that existence cannot be identified with any property. And this for the simple reason that nothing can have a property unless it exists.

Conclusion

Physical science studies physical reality. But it is in no position to establish that physical reality exhausts the whole of reality. The assertion that to be is to be physical is a meta-physical assertion in that it attempts go beyond physical reality to characterize reality as such. My second and third arguments show that this meta-physical assertion is false, and my first argument shows that it cannot be supported by natural science.

Suppose then that on a particular occasion I am thinking about a certain species of animal, say dogs —- not some specific dog, just dogs in general (but I mean domestic dogs, specifically, not dogs in the generic sense that includes wolves and coyotes). The Martian scientist is present and has his usual complete knowledge of my neurophysiological state. Can he tell on that basis alone what I am thinking about? Can he tell that I am thinking about dogs rather than about cats or radishes or typewriters or free will or nothing at all? It is surely far from obvious how he might do this. My suggestion is that he cannot, that no knowledge of the complexities of my neurophysiological state will enable him to pick out that specific content in the logically tight way required, and hence that physicalism is once again clearly shown to be false.

[. . .]

Suppose then, as seems undeniable, that when I am thinking about dogs, my state of mind has a definite internal or intrinsic albeit somewhat indeterminate content, perhaps roughly the idea of a medium-sized hairy animal of a distinctive shape, behaving in characteristic ways. Is there any plausible way in which, contrary to my earlier suggestion, the Martian scientist might come to know this content on the basis of his neurophysiological knowledge of me? As with the earlier instance of the argument, we may set aside issues that are here irrelevant (though they may well have an independent significance of their own) by supposing that the Martian scientist has an independent grasp of a conception of dogs that is essentially the same as mine, so that he is able to formulate to himself, as one possibility among many, that I am thinking about dogs, thus conceived. We may also suppose that he has isolated the particular neurophysiological state that either is or is correlated with my thought about dogs. Is there any way that he can get further than this?

The problem is essentially the same as before. The Martian will know a lot of structural facts about the state in question, together with causal and structural facts about its relations to other such states. But it is clear that the various ingredients of my conception of dogs (such as the ideas of hairiness, of barking, and so on) will not be explicitly present in the neurophysiological account, and extremely implausible to think that they will be definable on the basis of neurophysiological concepts. Thus, it would seem, there is no way that the neurophysiological account can logically compel the conclusion that I am thinking about dogs to the exclusion of other alternatives.

[. . .]

Thus the idea that the Martian scientist would be able to determine the intrinsic or internal contents of my thought on the basis of the structural relations between my neurophysiological states is extremely implausible, and I can think of no other approach to this issue that does any better. The indicated conclusion, once again, is that the physical account leaves out a fundamental aspect of our mental lives, and hence that physicalism is false.

I will now sum up BonJour's reasoning in my own way. BonJour is thinking about dogs. He needn't be thinking about any particular dog; he might just be thinking about getting a dog, which of course does not entail that there is some particular dog, Kramer say, that he is thinking about getting. BonJour's thinking has intentional content. The question is whether the Martian scientist can determine what that content is by monitoring BonJour's neural states during the period of time he is thinking about dogs. The content before BonJour's mind has various subcontents: hairy critter, mammal, barking animal, man's best friend . . . . But none of this content will be discernible to the neuroscientist on the basis of complete knowledge of the neural states, their relations to each other and to sensory input and behavioral output. Therefore, there is more to the mind than what can be known by even a completed neuroscience. Physicalism (materialism) is false.

1. There is a categorial difference between the subjectivity of the mental and the objectivity of the physical. Conscious experiences are essentially subjective in that they are necessarily such as to be epistemically accessible only to those who enjoy them. Objective items, on the other hand, are in principle epistemically accessible to many.

My cat, for example, recognizes me, but not as a member of homo sapiens, but as Big Pussy, the one who controls the food supply. She sees me not as a man, but as a big cat, indeed as something like her mother. (She crawls onto my belly and kneads my gut.) Associated with her take on me are certain kitty kat kwalia (cat qualia). But they are inaccessible to me, and would remain inaccessible even if I knew all there was to know about cat brains. I reckon there must be something it is like to be a cat, but I am not directly acquainted with what it is like.

The long and the short of it is that "physical facts are essentially objective in the sense that they can be understood from any point of view irrespective of the specific phenomenology of the understander's own experience." (Colin McGinn, Problem of Consciousness, p. 164) Not so for conscious experiences, whether human, feline, or Martian. (When philosophers speak of Martians, they mean extraterrestrials; the term 'Martian' is something like a synecdoche. Philosophers are weird, but they don't actually believe that there is intelligent life on Mars.)

I stress the categorial difference between the subjective and the objective. Here is second example of a categorial difference: that beween numbers (and abstracta generally) and concrete items like shoes and valve lifters. Categorial differences are unbridgeable, no matter how gradually you build the (impossible) bridge. Dennett take note.

There is an old-fashioned name for the fallacy of illicit category-jumping: metabasis eis allo genos. Perhaps we can pin said fallacy on our materialist friends.

2. The upshot is that the subjectivity of experience cannot be construed in objectivizing terms. In particular, qualia cannot be identified with states of the brain. But since it is the objectification of the subjective that is ruled out by the categorial difference between subjectivity and objectivity, rather than its materialization, it seems to follow that qualia can just as little be identified with states of a mental or spiritual substance. A res is a res whether it be a res extensa or a res cogitans. And a res is a thing, an object.

As McGinn puts it, "physicalism is not distinctively afflicted by the fact of subjectivity." (164, n. 18) Well said. Subjectivity appears to tell against both physicalism and substance dualism, and to tell against them equally. Qualia cannot be states of an object whether the object is made of material stuff, or 'spook stuff.' Stuff is stuff.

3. But is this really the case? One problem with the Nagel-McGinn parity argument is that a dualism of substances, properly understood, is not a dualism of stuffs. No sophisticated dualist recognizes his position in the 'spook stuff' strawman. See Dennett's Dismissal of Dualism.

A mental substance is a mental individual, indeed a mental continuant. It is a property-possessor, not a quantity of spook stuff. It is a parcel of consciousness with a wholly un-object-like nature. T.L.S. Sprigge, Theories of Existence, p. 46:

It is often difficult to get people to realize that the non-physical mind of which Cartesians speak is not, as some have thought it, a 'ghost in the machine' of the numan body, since ghosts and 'spirits' such as might appear in a seance are, in contrast to it, as physical, if made of finer stuff, as our ordinary bodies.

So although Nagel and McGinn are right that qualia cannot be states of any object, whether made of gross or subtle stuff, their parity argument fails to touch substance dualism. It fails because they misconstrue the claim that there are irreducible mental substances. This is not the claim that there is a special sort of stuff; it is the claim that consciousness occurs in individual 'parcels' possessing an unobjectifiable nature.

Perhaps we should speak of mental subjects rather than mental substances to avoid confusion. The correct points made by Nagel and McGinn have no tendency to show that qualia cannot be states of mental subjects.

One aspect of the mind-body problem is the problem of the subjectivity of conscious experience. As I tried to make clear in the last post, the subjectivity of conscious experience and the manner in which it connects to its physical substratum in the brain cannot be rendered intelligible from an objectifying 3rd-person point of view. Even if we had in our possession a completed neuroscience, we would not be able to understand how conscious experiences arise from the wetware of the brain.

But suppose someone objects as follows:

Robotics is making tremendous strides. In the future we may be able to build robots that are behaviorally indistinguishable from human beings. They will walk, talk, and look like human beings. One can even imagine them being made so human-like that a superficial physical examination would not reveal their robotic status. Imagine a 'female' robot that could pass a cursory gynecological examination and fool a gynecologist. . .

Suppose further that this robot not only passes all behavioral tests for being conscious, but really is conscious, really does feel embarrassed in the gynecologist's office, even though the physical substratum of her embarrassment is silicon-based. Suppose, in other words, that consciousness and indeed self-consciousness emerge in this robot.

We will then have an answer to the mind-body problem: we will know that consciousness is nothing special and nothing mysterious. We will know that it does not have a higher, meta-physical or super-natural origin, but is simply the byproduct of the functioning of a sufficiently complex machine, whether the machine be an artifact of a human artificer or the 'artifact' of natural selection.

But if we think about this carefully, we realize that even if this sci-fi scenario were realized, we would still not have a solution to the mind-body problem. For the problem is to render intelligible to ourselves, to understand, HOW consciousness can arise from matter. Building a robot in which consciousness DOES arise from matter does nothing to render understandable how the arisal occurs.

Suppose that there is a group of philosophizing robots. One of the problems under discussion might well be the mind-body problem in robots. The fact that they knew that they had been constructed by human robotics engineers in Palo Alto, California would do nothing to alleviate their puzzlement. In fact, one of the philosophizing robots could propose the theory that the emergence of consciousness in their silicon brains is not to be interpreted as a dependence of consciousness on matter, but as a Cartesian mlnd's becoming embodied in them: at a point of sufficient complexity, a Cartesian mind embodies itself in the robot.

In other words, what could stop a philosophizing robot from being a substance dualist? He knows his origin, or at least the origin of his body; but how does knowing that he is an artifact prevent his considering himself to be an artifact housing a Cartesian mind?

Our Cartesian robot would be able to exclude this possibility only if he understood HOW consciousness arises from matter. If he knew that, he would know that it does not have a higher origin.

In sum, even if we knew how to build conscious machines, such know-how would not be the knoledge necessary to solve the mind-body problem.

1. The issue is not whether a conscious experience, e.g., a pain sensation, can exist without a physical substratum. I am granting for the moment that conscious experiences cannot exist apart from brain processes. In a slogan: no brain, no pain. So the issue is not substance dualism. I am granting for the moment that the mind is not a substance. But note how substance is defined:

X is a substance =df X is metaphysically capable of independent existence.

2. And I think it is clear to Malcolm that 'pain sensation' in this discussion refers to pain qua felt, qua experienced or lived through, pain as Erlebnis as Husserl would say, and NOT to the corresponding brain state as this would appear to an objective, 3rd person point of view. What is of interest here are the qualitative characters (features, properties) of the state I am in when I am in pain. When you are in pain, you know what it feels like, and no one, not even Bill Clinton, can feel your pain. Compassionate as he no doubt is, not even he can feel numerically the same pain that you are feeling at a given time. And what is true of Bill is a fortiori true of Hillary.

3. Now the question is precisely this: If one knew everything there was to know about the brain, the CNS, etc., would that knowledge render intelligible the connection between the brain process (firing of Delta A fibers, or whatever it might be) and the pain as consciously experienced? If we were in possession of a completed neuroscience, would we be able to say: Now we understand the relation between conscious experience and brain functioning and can finally lay to rest at least this aspect of the mind-body problem?

4. I answer this question in the negative. Here is an argument:

a. The sensory quale (the felt pain) is essentially subjective.
b. The corresponding brain state is not essentially subjective.
Therefore
c. The quale is not identical to the brain state.
Therefore
d. Exhaustive knowledge of the brain provides no knowledge about qualia or their link to brain states. The link remains unintelligible.

With respect to the conjunction of a variant of (a) and a variant of (b), Malcolm wrote:

How do you know this? In the physicalist view, the subjective experience is indeed created by the brain's being in a particular physical state. I would argue that whenever a brain gets into this state, it necessarily entails that a subjective experience is being had.

I think this quotation shows misunderstanding on Malcolm's part. I am willing to grant that when the brain is in a certain state a pain sensation arises. But that is not the issue. The question concerns the HOW of that arisal, the intelligibility of that emergence.

It also shows misunderstanding when Malcolm asks me how I know that the felt pain, unlike the brain state, is essentially subjective. I know that in the same way that I know that Clinton can't feel my pain. Pains are private. They are not 3rd-person accessible. Pains are such that esse = percipi. WYSIWYG. That is not the case for physical objects.

5. So what is going on here? Why doesn't Malcolm agree with me? One possibility is that we are asking different questions. I formulated my question in #3 above. Perhaps Malcolm is not interested in — or doesn't understand the force of — that question. Perhaps his question is: Can a mind exist apart from a brain? But that is not the question I was asking.

Now if fitting into a causal pattern is what makes mental states mental, then two scenarios which seem possible are really impossible. In the one, a person's conscious experience gradually fades out, while sensory input and behavioral output remain the same. On this scenario, the person becomes a zombie, a being physically and behaviorally indistinguishable from an ordinary conscious person but without conscious experience.

In the second scenario, there is blooming, buzzing conscious experience but paralysis blocks it behavioral manifestation. As noted, on functionalism both scenarios are impossible. For if the mentality of a mental state is just its functional role, then conscious experience cannot fade out as long as the role is being instantiated. And if functionalism is true, then conscious experience cannot continue to occur if all conscious links to behavioral manifestation are severed.

But presumably both scenarios are possible. Indeed, there are cases in which the second is actual. So Modus Tollens assures us that functionalism is false.

Let's take a closer look at the first argument:

1. It is possible that a person's conscious experience gradually fade out, while input, output, and intervening states remain the same.

2. If functionalism is true, then it is not the case that (1).

Therefore

3. It is not the case that functionalism is true.

The crucial premise is (1). If is very difficult to see why occupancy of a certain causal role should be sufficient for a particular physical state's being a conscious state. After all, the physical states of other organs such as the heart or the kidneys occupy causal roles without their occupancy of such roles being sufficient for their being conscious states. No one is going to claim that the kidneys are a second seat of consciousness.

At this point one may be tempted to give up on functionalism and return to the notion that there is something intrinsic to brain states that makes them mental states. But then why are only some states of the brain conscious? And why do we find consciousness only in the brain? Colin McGinn writes:

The materials of the brain are of the same kind as those found in non-conscious nature, so how could they explain why consciousness is found in the brain but not elsewhere (for example, the kidneys)? It follows that, no matter how well we come to understand the chemistry of the brain, this will not enable us to understand consciousness. (The Problem of Consciousness, p. 208)

One aspect of the mind-body problem is the problem of understanding how the brain can give rise to consciousness. McGinn's point is that even if we had a complete understanding of the brain from the perspectives of physics, chemistry, electrochemistry, evolutionary biology . . . this objective understanding of the brain would do nothing to render intelligible how this marvelously complex chunk of the physical world can give rise to consciousness.

McGinn is not a substance dualist. He is not saying that consciousness can exist without a physical substratum. His point is rather that the identification of conscious experiences with brain states is unintelligible, a mystery.

'Multiply' is a picturesque way of saying posit. So the principle enjoins us to refrain from positing more types of entity than we need to explain the phenomena that need to be explained. It is obvious that (OR*) does not tell us to prefer theory T1 over theory T2 if T1 posits fewer types of entity than T2. What it tells us is to prefer T1 over T2 if T1 posits fewer types of entity AND accounts adequately for all the data. So there is a trade-off between positing and accounting.

It goes without saying that securing agreement on just what the data are, and whether a given theory accounts for them adequately, is a messy business. It is especially messy when, as is the case here, what one is seeking are philosophical rather than scientific explanations.

How does Occam's Razor bear upon the question of metaphysical naturalism (which is to be distinguished from ethical, epistemological, and methodological naturalism)? As follows. If naturalism accounts for all the data adequately, then I say we should be naturalists. Thus there is arguably a presumption in favor of naturalism, a presumption that rests on the Razor.

Metaphysical naturalism (MN) may be defined as the doctrine that the world, the totality of entities, is identical to the space-time system. This is essentially D. M. Armstrong's definition. (A World of States of Affairs, p. 5.) If MN is true, then there is no God as classically conceived, no unembodied or disembodied finite minds, no abstracta or Platonica such as Fregean propositions, and no unexemplified universals. (MN as defined does allow for immanent physical universals: see Armstrong.)

Some identify MN with atheism, the denial that God as classically conceived exists. That is a mistake in my book: MN entails atheism, no doubt, but is not logically equivalent to it, since atheism does not entail metaphysical naturalism. McTaggart was an atheist but not a metaphysical naturalist.

Suppose there are three candidate entity-types, basic and mutually irreducible: bodies, minds, abstracta. The naturalist can be understood to be saying that the second two categories are empty and that their members are not needed to explain the data.

It follows that there are several ways to be an anti-naturalist. One way is to say that we need minds and bodies but not abstracta. Another is to say that we need bodies, minds, and abstracta. A third is to say that we need bodies and abstracta but no minds. A fourth is to say that we can get by just with minds. (Berkeley, McTaggart) A fifth is to say that we need only minds and abstracta. A sixth is to say that we can scrape by on abstracta alone. (I seem to recall a logician named Fitch who thought everything is at bottom a proposition or a construction out of propositions -- but I could easily be wrong about that.)

From the foregoing it should be clear that Occam's Razor does not support MN by itself, but only together with an antecedent acceptance of bodies as irreducibly real. But given the latter acceptance, then OR* enjoins us to try to explain the data without invoking irreducible minds or mental contents (qualia, e.g.) or abstracta.

So this is what I am interested in discussing: Can naturalism explain everything that needs to be explained? If it can, then we ought to be naturalists, or at least the pressure is on to accept naturalism. God might still exist even if everything apart from God could be explained without reference to God. But then what reason would one have to posit God? Mystical experience of God? God's self-revelation through his prophets as recorded in scripture? Perhaps, but then the question of the veridicality of these sources of putative knowledge becomes very pressing indeed. Metaphysical naturalism will most like bring epistemological naturalism and scientism in its train and thus a foreclosing on all sources of knowledge apart from science.

So I say that the pressure is on to accept naturalism if it can explain what needs to be explained. Of course, I don't think it can explain what needs to be explained, which is why I am an anti-naturalist. I am not an anti-naturalist because I am a theist, I am an anti-naturalist because naturalism fails to explain what needs to be explained. I have been building my case slowly, but it is far from complete.

But note well: to argue against naturalism is to not argue for substance dualism. For there are other options such as absolute idealism. If everything is a mind or a content in a mind, then that is as parsimonious an explanation as an explanation that states that everything is either a body or a construction from bodies.

What needs to be explained? This requires a separate post.

Since there is a presumption in favor of naturalism, it is appropriate to proceed as I have been proceeding, namely, challenging naturalists to show how their theories work and account for the data. Pollack et al. may feel this to be unfair because I have them on the defensive; but it seems to me that the presumption in favor of naturalism makes to reasonable to see if we can be satisfied by it. If we can, then there is no need to posit anything beyond the natural.

Note also -- and this may apply to Kevin Kim -- the untenability of substance dualism, say, does not show the tenability of naturalism. After all, they could both be false and/or untenable.

Suppose Socrates Jones is in some such state as that of perceiving a tree. The state is classifiable as mental as opposed to a physical state like that of his lying beneath a tree. What makes a mental state mental? That is the question.

The functionalist answer is that what makes a mental state mental is just the causal role it plays in mediating between the sensory inputs, behavioral outputs, and other internal states of the subject in question. The idea is not the banality that mental states typically (or even always) have causes and effects, but that it is causal role occupancy, nothing more and nothing less, that constitutes the mentality of a mental state. The intrinsic nature of what plays the role is relevant only to its fitness for instantiating mental causal roles, but not at all relevant to its being a mental state. Compare a piston in an engine. You can't make a piston out of chewing gum, but being made of steel is no part of what makes a piston a piston. A piston is what it does within the 'economy' of the engine. Similarly, on functionalism, a mental state is what it does. This allows, but does not entail, that a mental state be a brain or CNS state. It also allows, but does not entail, that a mental state be a state of a computing machine.

To illustrate, suppose my cat Zeno and I are startled out of our respective reveries by a loud noise at time t. Given the differences between human and feline brains, presumably man and cat are not in type-identical brain states at t. Yet both man and cat are startled: both are in some sense in the same mental state, even though the states they are in are neither token- nor type-identical. The functionalist will hold that we are in functionally the same mental state in virtue of the fact that Zeno's brain state plays the same role in him as my brain state plays in me. It does the same mediatorial job vis-a-vis sensory inputs, other internal states, and behavioral outputs in me as the cat's brain state does in him.

On functionalism, then, the mentality of the mental is wholly relational. And as Armstrong points out, "If the essence of the mental is purely relational, purely a matter of what causal role is played, then the logical possibility remains that whatever in fact plays the causal role is not material." This implies that "Mental states might be states of a spiritual substance." Thus the very feature of functionalism that allows mentality to be realized in computers and nonhuman brains generally, also allows it to be realized in spiritual substances.

Whether this latitudinarianism is thought to be good or bad, functionalism is a monumentally implausible theory of mind. There are the technical objections that have spwaned a pelagic literature: absent qualia, inverted qualia, the 'Chinese nation,' etc. Thrusting these aside, I go for the throat, Searle-style.

Functionalism is threatened by a fudamental incoherence. The theory states that what makes a state mental is nothing intrinsic to the state, but purely relational: a matter of its causes and effects. In us, these happen to be neural. Now every neural state has causes and effects, but not every neural state is a mental state. So the distinction between mental and nonmental neural states must be accounted for in terms of a distinction between two different sets of causes and effects, those that contribute to mentality and those that do not. But how make this distinction? How do the causes/effects of mental neural events differ from the causes/effects of nonmental neural events? Equivalently, how do psychologically salient input/output events differ from those that lack such salience?

Suppose the display on my monitor is too bright for comfort and I decide to do something about it. Why is it that photons entering my retina are psychologically salient inputs but those striking the back of my head are not? Why is it that the moving of my hand to to adjust the brightness and contrast controls is a salient output event, while unnoticed perspiration is not?

One may be tempted to say that the psychologically salient inputs are those that contribute to the production of the uncomfortable glare sensation, and the psychologically salient outputs are those that manifest the concomitant intention to make an adjustment. But then the salient input/output events are being picked out by reference to mental events taken precisely NOT as causal role occupants, but as exhibiting intrinsic features that are neither causal nor neural: the glare quale has an intrinsic nature that cannot be resolved into relations to other items, and cannot be identified with any brain state. The functionalist would then be invoking the very thing he is at pains to deny, namely, mental events as having more than neural and causal features.

Clearly, one moves in a circle of embarrassingly short diameter if one says: (i) mental events are mental because of the mental causal roles they play; and (ii) mental causal roles are those whose occupants are mental events.

I think that honest reflection strongly suggests that nothing we could ever empirically discover about the brain could provide a fully satisfying account of consciousness. We shall either find that the properties we encounter are altogether on the wrong track or we shall illicitly project traits of mind into the physical basis. (The Problem of Consciousness, Blackwell, 1991, p. 28)

McGinn expands on the point in a footnote to which I have added some emphases:

This latter tendency gives rise to illusions of understanding. We think we are seeing how consciousness depends on the brain when all we are doing is reading consciousness into the physical basis. The tendency is particularly compelling when the brain is seen as a computer: thinking of neurons as performing computations, we are tempted to credit them with conscious states (or proto-conscious states). Then it seems easy enough to see how neurons could generate consciousness. But, of course, this just pushes the problem back (as well as being false): for how do these conscious properties of neurons arise from their physical nature? (Panpsychism now threatens.) If we are to describe physical processes computationally, then we must be clear that this does not involve consciousness -- and then it will also be clear that we can not get consciousness out of such descriptions. Either we presuppose what we should be explaining or we find ourselves as far away as ever from our explanandum.

Marvelously complex as it is, the brain is just another chunk of the physical world. Study it till doomsday with the most sophisticated instruments, map every cubic millimeter of it, establish detailed correlations between brain regions and types of conscious phenomena -- and what do you accomplish? You learn more and more about a highly complex piece of meat. What you do not accomplish is any understanding of consciousness, which is the presupposition of establishing all those correlations in the first place. Think about it: if the experimental subject is not 'being appeared to redly' as Chisholm would say, not grooving on qualia, then she cannot report anything to the presiding neuroscientist who is poking around inside her skull.

Natural science would treat everything as if it were exhaustively understandable in 3rd-person terms. Unfortunately, the 3rd person point of view presupposes the 1st-person point of view as a condition of its own possibility. Thus naturalistic objectifying science cannot explain the very thing that makes it possible. Here we appear to reach a necessary limit to scientific understanding.

McGinn is right to speak of "illusions of understanding." Many naturalists succumb to such illusions. They think they understand what they don't understand. They think their fancy pseudo-theories actually illuminate the nature of cosnciousness when they do no such thing. McGinn has the intellectual honesty to admit this even though he himself insists that consiousness "must fit into the natural order of things somehow." (p. 47) But others -- and Dennett appears to be one of them -- fall into sophistry in their zeal to ram naturalism through.

1. I am assuming that our cognitive faculties are reliable. Thus my question is not whether they are reliable, but whether it is rational to hold that they are reliable if one also holds they are the accidental products of blind evolutionary processes.

2. By 'reliable,' I mean reliable for producing true beliefs more often than not when our faculties are functioning properly in their appropriate environments. A true belief is one that corresponds to the way the world is in itself. If my belief that a is F is true, then a is F -- whether or not anyone believes it. Truth puts one in touch with reality.

3. Reliability is a normative concept. Compare trustworthiness. To say that a person is trustworthy is not merely to say that the person CAN be trusted, but that he is WORTHY of being trusted, that he deserves trust or merits trust. (Anyone who is trusted, can be trusted; but this is not to say that anyone who is trusted is trustworthy.) Hence to say that our cognitive apparatus (inner sense, outer sense, discursive reason, and whatever else one wants to include) is reliable or trustworthy is not to say that we as a matter of fact rely or have relied on it, or that we can rely on it, but that we are justified in relying on it due to a certain intrinsic aptness of the faculty for producing true beliefs. A reliable faculty is one that is worthy of being relied upon to produce true beliefs.

4. Pollack says in effect that it is rational to trust our faculties to produce true beliefs because such trust has proven to have survival-value. Although it is true that we and our faculties have arisen by accident via blind evolutionary processes from less complex forms of life, our faculties are nonetheless reliable because we have been relying on them and we have been successful in the struggle for existence.

5. If this is what Pollack means -- and it may not be -- then I think a mistake has been made, namely, an illicit inference from the factual assertion that our reliance on our faculties has worked out well as far as survival as a species goes to the normative assertion that our faculties are worthy of being relied upon to produce true beliefs.

I don't see how success justifies. I don't see how one validly moves from (a) Trusting our faculties, we have been successful to (b) Our trust in our faculties is justified. For if our faculties arose by accident, then it is sheer chance, a mere contingent fact, that so far they have been productive of true beliefs. If they weren't designed to track truth, but merely have happened to track truth so far, then we have no reason to trust them.

6. I don't believe it will do any good for Pollack to say that our faculties did not arise by accident but were designed by mindless processes, or anything along those lines. (Compare Dennett's silly talk of Mother Nature designing this and that.) For that is to misuse the word 'design.' To be designed is to be designed for a purpose by a being who is purposive. Something that arises from natural selection operating upon random mutations may appear to be designed, but it makes no sense to say that such a thing is designed. Thus the heart appears to have been designed for a purpose, namely, to pump blood. But the mere appearance of design does not entail design, and if the heart came about by undirected evolutionary processes, then the corrct thing to say is that the heart was not designed, and that the appearance of design is a mere appearance and no part of reality.

7. So I persist in my view that it is not rational to hold BOTH that our cognitive faculties are reliable, AND that they are accidental products of blind evolutionary processes.

Of course, the two rock piles might have come into existence via purely natural causes: a rainstorm might have dislodged some rocks with gravity plus other purely material factors accounting for their placement. Highly unlikely, but possible. This possibility shows that the appearance of design does not entail design.

Nevertheless, your taking of the rock piles as trail markers presupposes (entails) that they are designed. It would clearly be irrational to take the piles as evidence of the trail's direction while at the same time maintaining that their formation was purely accidental. And if you found out that they had come into being by chance due to an earthquake, say, you would cease interpreting them as meaning anything, as providing information about the trail. One must either take the cairns as meaningful and thus designed or as undesigned and hence meaningless. One cannot take them as both undesigned and meaningful. For their meaning -- 'the trail goes that-a-way' -- derives from a designer.

Now consider our incredibly complex sense organs. We rely on them to provide information about the physical world. I rely on eyesight, for example, both to know that there is a trail and to discern some of its properties. I rely on hearing to inform me of the presence of a rattlesnake. I rely on my brain to draw inferences from what I see and hear, inferences that purport to be true of states of affairs external to my body. The visual apparatus (eye, optic nerves, visual cortex and all the rest) exhibits apparent design. It is as if the eyes were designed for the purpose of seeing. But the appearance of design is no proof of real design. And indeed, human beings with their sensory apparatus are supposed to have evolved by a process of natural selection operating upon random mutations. If so, eye and brain are cosmic accidents.

But if this is the case, how can we rely on our senses to inform us about the physical world? If eye and brain are cosmic accidents, then we can no more rely on them to inform us about the physical world than we can rely on an accidental collocation of rocks to inform us about the direction of a trail.

As a matter of fact, we do rely on our senses. Our reliance may be mistaken in particular cases as when a bent stick appears as a snake. But in general our reliance on our senses for information about the world is justified. Our senses are thus reliable: they tend to produce true beliefs more often than not when functioning properly in their appropriate environments. We rely on our senses in mundane matters but also when we do science, and in particular when we do evolutionary biology. The problem is: How is our reliance on our sense organs justified if they are the accidental and undesigned products of natural selection operating upon random mutations?

To put it in terms of rationality: How could it be rational to rely on our sense organs (and our cognitive apparatus generally) if evolutionary biology in its naturalistic (Dawkins, Dennett, et al.) guise provides a complete account of this cognitive apparatus? How could it be rational to affirm both that our cognitive faculties are reliable, AND that they are accidental products of blind evolutuionary processes? I agree with Richard Taylor who writes:

. . . it would be irrational for one to say both that his sensory and cognitive faculties had a natural, nonpurposeful origin and also that they reveal some truth with respect to something other than themselves, something that is not merely inferred from them. (Metaphysics, 3rd ed. p. 104)

This suggests the following design argument:

1. It is rational to rely on our cognitive faculties to provide access to truths external to them.

2. It is rational to rely on our cognitive faculties only if they embody the purposes of an intelligent designer.

Therefore

3. Our cognitive faculties embody the purposes of an intelligent designer.

To resist this argument, the naturalist must deny (2). But to deny (2) is to accept the rationality of believing both that our cognitive faculties arose by accident and that they produce reliable beliefs. It is to accept the rationality of something that, on the face of it, is irrational.