consciousness experience reduction and identity

7/31/2019 Consciousness Experience Reduction and Identity

1/22

PHILOSOPHICAL PSYCHOLOGY, VOL. 17, NO. 2, 2004

Conscious experience, reduction and

identity: many explanatory gaps, onesolution

LIAM P. DEMPSEY

ABSTRACT This paper considers the so-called explanatory gap between brain activity and conscious

experience. A number of different, though closely related, explanatory gaps are distinguished and a

monistic account of conscious experience, a version of Herbert Feigls dual-access theory, is

advocated as a solution to the problems they are taken to pose for physicalist accounts of mind.

Although dual-access theory is a version of the mind-body identity thesis, it in no way eliminates

conscious experience; rather, it provides a parsimonious and explanatorily fruitful theory of the

consciousness-body relation which faithfully preserves the nature of conscious experience while going

quite far in bridging the various explanatory gaps distinguished below.

1. Introduction

The phrase explanatory gap has a great deal of currency in the contemporary

consciousness literature. Indeed, it is taken by many to suggest the ontological

irreducibility or non-physical nature of qualia, but there are a number of senses in

which this phrase is used. Coined by Levine (1983), the phrase explanatory gap

has what we might call a technical or philosophical sense. Call this the reductive

explanatory gap. There is also the more general usage of the phrase meant to refer to

the uniquely mysteriousperhaps non-physicalnature of conscious experience.Call this the intuitive explanatory gap. The intuitive gap can itself be divided into at

least three closely related types of concerns: epistemic asymmetries, bruteness and

incomprehensibility, and seeming differences.

In what follows, both explanatory gaps are considered and dual-access theory

a version of mind-body identity theoryis proffered as a solution to both. Thus,

departing from received wisdom in philosophy of mind and psychology which holds

that mind-body identity is not in the cards [1], I advance a view that takes qualia to

be identical to certain neurophysiological properties of the human central nervous

system. According to such an account, the prima facie problems for qualia-body

Liam P. Dempsey, Dalhousie University, 5252 Tobin Street, Apt. 704, Halifax, Nova Scotia,

Canada B3H 4K2 email: ldempsey@dal ca


2/22

226 L. DEMPSEY

identity raised by the explanatory gaps are obviated in a way that faithfully preserves

the reality and nature of conscious experience.

2. The reductive gap

Levines (1983, 1993) explanatory gap [2] can be seen as a reaction to Kripkes

(1980) argument against a materialist account of the mind-body relation. For

Kripke, both pain and C-fiber firings, like water and H2O, are rigid

designators; they designate the same things in every possible world in which they

designate at all. Thus, if water and H2O or pain and C-fiber firings are identical, they

are necessarily identical. Yet, both identities appearto be contingent. This appearance

of contingency can be explained away in the case of water but not pain. While it both

seems like we can imagine water that is not H2O and excited C-fibers that are not

painful, in the case of conscious experiences like pain, there is no appearance/reality

distinctionthey are what they seem to be, and they dont seem to be brain states.

In the case of water/H2O, on the other hand, the appearance of contingency can be

explained away when it is realized that what is really being imagined is not that water

is not H2O but that waterish stuffstuff that, superficially, is just like wateris not

H2O. Of course, waterish stuff is not a rigid designatorit does not designate the

same stuff in every possible worldsince it may, in some possible worlds, designate

something with the molecular composition XYZ [3]. Again, in the case of pain, this

strategy will not work since the appearance of pain just is pain, and so, we cannot

explain away the appearance while leaving the reality untouched. According to

Kripke, then, mind-body identity is not analogous to other empirical, a posterioriidentities. In all a posteriori identities, there is an appearance of contingency that can

usually be explained away; but in the case of mind-body identities, this appearance

of contingency is both robust and persistent.

Unlike Kripke, Levine does not believe any metaphysical consequences follow

from this line of reasoning. What it actually shows is that there is an explanatory gap

between conscious experience and, say, the neurophysiological activity with which it

is co-instantiated. What is needed is a reductive explanation of conscious experi-

ence. A reductive explanation, according to Levine and the other proponents of the

explanatory gap, provides an epistemic necessitation of the pre-theoretic macro fea-

tures, of, say, water, from knowledge of the theoretic micro features appealed to in

the chemical theory of H2O. Reductive explanations explain the phenomenon being

reduced, and, according to Levine (1993, p. 550), a theoretical reduction is

justified principally on the basis of its explanatory power. A physicalist theory of

qualia, on the other hand, reveals our inability to explain qualitative character in

terms of the physical properties of sensory states (Levine, 1993, p. 543). In the case

of water and H2O, the identification affords a deeper understanding of what water

is by explaining its behavior, whereas in the case of qualia, the subjective character

of the qualitative experience is left unexplained (Levine, 1993, p. 550), and thus,

our understanding of the experience is incomplete. The basic idea, for Levine (1993,p. 549), is that, Reduction should explain what is reduced, and the way to tell

whether this has been accomplished is to see whether the phenomenon to be


3/22

CONSCIOUS EXPERIENCE, REDUCTION AND IDENTITY 227

reduced is epistemologically necessitated by the reducing phenomenon. Therefore,

what is missing in the case of consciousness, according to Levine, is a necessitation

of the facts about the qualitative nature of qualia from the facts about the brain

states that underpin them. We do have an epistemic necessitation of the facts about

the pretheoretic macro features of water from our knowledge of the chemical theoryof H2O molecules. So we can, for example, explain how and why water boils in

certain circumstances by appeal to facts about H2O [4]. In this case, we have an

example of a macro feature of water being explained by appeal to the chemical

theory of the kind of molecules water is identical with; thus the identity of water and

H2O is informative and explanatory in a way that the identity of pain and C-fiber

excitation is not.

Despite the fact that reductive explanations are here being employed to explain

a posteriori reductions, they have an a priori component; specifically, they require a

conceptual analysis of the phenomenon to be reduced in terms of its causal role. In

general, a reductive explanation is, according to Levine, a two-stage process. First,

there is the a priori process of defining the property to be reduced in terms of its

causal role, and then there is the a posteriori or empirical work of locating the

mechanisms that underlie that causal role. Consider again the reduction of water to

H2O. First we determine the causal role of our pretheoretic concept of water. Once

it is established that H2O fills the causal role that defines water, we can say that

waterH2O. In addition, according to Levine, if water can be analyzed in terms of

its causal role, then its behavior can be deduced from facts about the chemical

theory of the properties that fill that role. In other words, facts about the chemical

theory of H2O necessitate facts about the macro properties of water. For example,the fact that, at sea level, water boils at 100(C is deducible from the chemical theory

of H2O. In general, if water can be analyzed in this way, we will have the resources

to explain all of its macro properties by appealing to the chemical theory of H 2O [5].

This reduction strategy will not work in the case of qualia because, according

to Levine, there are elements of our concept of qualitative character that are not

captured by features of its causal role. And reduction is only explanatory when by

reducing an object or property we reveal the mechanisms by which the causal role

constitutive of that object or property is realized (Levine, 1993, p. 553). Again,

Levine does not draw any metaphysical conclusions from this line of reasoning [6].

His point, it would seem, is that if qualia are physical in nature, we lack an

explanation of why something with such and such physical properties should have

the phenomenal character it does or, indeed, any phenomenal character at all. The

consciousness-body relation remains mysterious, and because qualitative character

is left unexplained by the physicalist or functionalist theory that it remains conceiv-

able that a creature should occupy the relevant physical or functional state and yet

not experience qualitative character (Levine, 1993, p. 548).

3. The intuitive explanatory gap

It is common for people to find mind-body identity counter-intuitive, especially in the

case of conscious experience The identification of conscious experiences and neural


4/22

228 L. DEMPSEY

activity leaves many with a feeling of nagging mysteriousness. There is a feeling of

things unexplained, of questions without satisfactory answers. Explanatory gap, in

this looser sense, refers to certain circumstances that motivate intuitions against the

physical account of conscious experience. There are at least three areas of concern

that contribute to this state of affairs: (1) epistemic asymmetries; (2) bruteness andincomprehensibility; and (3) seeming differences. Each is discussed in turn.

3.1. Epistemic asymmetries

There are, of course, the well known epistemic asymmetries inherent in the mind-

body relation. Only I have direct access to my own qualia, only I can feel my pain;

and while I can observe your pain behavior and can infer many of your sensations, I

do not have the sort of direct access to your conscious experiences that I have to my

own. Whether conscious experiences are completely private or completely incorrigi-

ble is, here at least, beside the point; they are more private, and one is, at least, more

sure of them, for while I may often be wrong about what others are feeling, I am

rarely wrong about what I am feeling. To put the concern differently, qualia, unlike

brain states, are subjective phenomena; and as Block (2002, p. 395) recently

queried, [h]ow could one property be both subjective and objective?

Consider, then, the sorts of concerns Nagel emphasizes (1973, 1986). Physical-

ist accounts of phenomena are objective, involving only public phenomena, while

conscious experiences are fundamentally subjective. Any physicalist account of

qualia, then, will be objective and will necessarily ignore the essential subjective

nature of the explanandum. It might be arguedand is argued by Nagelthat thesesorts of considerations speak against the adequacy of the physicalist world-view. For

our purposes, however, the question is simply, how can qualia be physical, let alone

neurophysiological, if they are so fundamentally different from all other physical

phenomena? In short, the argument goes, such a radical difference in epistemic

access speaks strongly against the identity in question, and shows, at the very least,

that neurophysiological accounts of conscious experience lack the resources to

explain such epistemic asymmetries.

3.2. Bruteness and incomprehensibilityThe second set of misgivings involves the apparent bruteness of the relationship. The

issue of bruteness would seem to be very closely related to Kripke and Levines

concerns over apparent contingency. One suspects that if a reductive explanation

account of conscious experience were possible, much of the concern over the

apparent bruteness of the qualia-body relation would be alleviated. Indeed, the

intuitions that motivate Levine are very similar to the concerns noted here. Consider

Levines (1983, p. 357) remark that, The identification of the qualitative side of

pain with C-fiber firing leaves the connection between it and what we identify it

with completely mysterious. One might say, it makes the way pain feels into merelya brute fact. For Levine, then, the identity of quale types with neurophysiological

types admits no explanation of why the quale type is identical with the specific


5/22


neurophysiological type in question; their identity, if it is a fact, is seemingly a brute

fact, and, according to Levine, this is quite troubling and speaks to the unique

mysteriousness of qualia.

The seeming bruteness of the qualia-body relation has a long history of

confounding the intuitions of those interested in the mind-body problem. Considerthe following remarks by two nineteenth-century scientists, T.H. Huxley and John

Tyndall [7]. First, Huxleys (1866, p. 193, emphasis added) well-known remark:

But what consciousness is, we know not; and how it is that anything so remarkable

as a state of consciousness comes about as the result of irritating nervous tissue, is

just as unaccountable as the appearance of Djin when Aladdin rubbed his lamp or

as any other ultimate fact of nature. Not only is Huxley impressed by the seeming

differences of the two phenomena (see below), but also by the apparent bruteness of

their relationship. Why does conscious experience emerge from excited nervous

tissue? Why is it nervous tissue that underpins consciousness and not some other

physical phenomenon? Apparently, the relation is an ultimate fact of nature for

which further explanation is incomprehensible. Tyndall expresses very similar con-

cerns when he writes:

Granted that a definite thought, and a definite molecular action in the

brain, occur simultaneously; we do not possess the intellectual organ, nor

apparently any rudiment of the organ, which would enable us to pass, by

a process of reasoning, from the one to the other. They appear together,

but we do not know why. Were our minds and senses so expanded,

strengthened, and illuminated, as to enable us to see and feel the very

molecules of the brain; were we capable of following all their mo-

tions and were we intimately acquainted with the corresponding states of

thought and feeling, we should be as far as ever from the solution of the

problem, How are these physical processes connected with the facts of

consciousness?. The chasm between the two classes of phenomena would

still remain intellectually impassable. (Tyndall, 1868/1898, p. 86)

Even when we observe a strong co-variation between a certain conscious experience

and a certain type of brain activity, we inevitably lack an explanation of why they

co-vary. It wont help, Tyndall contends, to have intimate knowledge of the brain

activity that co-varies with an experience, even if that knowledge is at the molecular

level, since such knowledge would not speak to the relation itself. Indeed, there is

no process of reasoningno epistemic necessitationthat would lead us from

facts about the brain to facts about conscious experiences.

According to Tyndall, the nature of the relation is seemingly inexplicable by any

conceivable process of reasoning. Indeed, in agreement with McGinn (1989), he

asserts that we do not even possess the intellectual capacity for such an explanation

[8]. Perhaps his concern arises from the empirical (a posteriori) nature of the

proposed identities; after all, such identities seemingly allow for the conceivability of

dualism and even phenomenal zombies. However, this is, seemingly, not whatTyndall has in mind. Rather, his concern is that while many of the inferences of

science are based on empirical association the case of consciousness is apparently


6/22

230 L. DEMPSEY

unique. Many of the inferences of science, Tyndall (1868/1898, p. 86) explains,

are of this characterthe inference, for example, that an electric current, of a given

direction, will deflect a magnetic needle in a definite way. However, the relation-

ship between consciousness and the brain, he contends, is quite different. An

explanation of how a magnet deflects a needle, if not demonstrable, is conceivable,and that we entertain no doubt as to the final mechanical solution of the problem.

But the passage from the physics of the brain to the corresponding facts of

consciousness is inconceivable as a result of mechanics (Tyndall, 1868/1898,

p. 86). Tyndalls concern, then, is not the empirical nature of the relation but the

apparent inconceivability of any mechanism by which the brain generates conscious

experience. Such a mechanism, it would seem, is nothing like the mechanics of the

physical world and Tyndall sees no hope of ever explaining it.

What is being demanded, then, are answers to the following sorts of questions:

First, there are questions such as: how can conscious experience emerge from any

physical mechanism? and why does an experiential type emerge from one neuro-

physiological type and not another? Second, there are questions such as: why is it

that certain types of neural activity are conscious experiences for their owners? and

why is one experiential type identical with one type of neural activity and not some

other type?

3.3. Differences in appearance

To paraphrase McGinn (1989), how can a rich color experience arise from gray

soggy nervous tissue? How can two things that are seemingly so different in kind beso intimately related, let alone identical? In short, the brain appears to be quite

different from the conscious experiences associated with it. Perry (2001) takes this

line of reasoning to follow from what he calls the experience gap. The gap between

conscious experience and the experience of brain states (through, for example, ones

physical senses) is so radical that the identification of the two seems absurd [9]. In

a critique of nineteenth-century materialists, A.C. Ewing puts the point this way:

Nineteenth-century materialists were inclined to identify mental

events with processes in the central nervous system or brain. In order to

refute such views I shall suggest your trying an experiment. Heat a piece ofiron red-hot, then put your hand on it, and note carefully what you feel.

You will have no difficulty in observing that it is quite different from

anything which a physiologist could observe. The throb of pain experi-

enced will not be like anything described in textbooks of physiology as

happening in the nervous system or brain. The physiological and the

mental characteristics may conceivably belong to the same sub-

stance but at least they are different in qualities, indeed as different in

kind as any two sets of qualities. (Ewing, 1962, p. 110)

According to Ewing, then, conscious experience and brain activity are as different inappearance as any two things could be. No one would ever mistake a searing pain

for the brain state with which it correlates The neurosurgeon who is operating on


7/22


my brain does not fear that my anesthesia will wear off for her sake! Therefore, the

argument goes, qualia must be distinct from the neurophysiological properties with

which they co-vary. At the very least, these apparent differences must be explained.

4. Dual-access theory and the explanatory gaps

4.1. Monism and dual-access theory

According to Feigls (1958, 1967, 1970) dual-access theory, phenomenal predicates

denote the same properties as neurophysiological predicates [10]. The identity of

conscious and neurophysiological phenomena is of the a posteriori and extensional

sort. In Feigls (1958, p. 445) words, [t]he raw feels of direct experience as we

have them, are empirically identifiable with the referents of certain concepts of

molar behavior theory and these in turn are identifiable with the referents of some

neurophysiological concepts. The case for qualia-body type identity takes the form

of an argument to the best explanation. The identification of qualia with certain

neurophysiological processes and properties substantively simplifies the ontology of

consciousness. Moreover, by locating qualia within the causal economy of sentient

organisms, qualia-body identity affords a straightforward explanation of the causal

powers of qualia, and by alleviating the threat of epiphenomenalism, the spectre of

eliminativism is dispelled. Thus, not only is qualia-body identity parsimonious, it

also provides a robust account of the reality of conscious experience, securing its

place within the causal web of the natural world.

Dual-access theory, then, holds that qualia are type identical with certainneurophysiological properties and processes; for example, (human) pain qualia are

identical with certain types of C-fiber excitation which are appropriately integrated

and situated in a human subjects nervous system. Nevertheless, we have access to

pain/excited C-fibers from more than one perspective; although I and my neurosur-

geon may be focusing on the same thing when she stimulates my C-fibers, I am

directly acquainted with this stimulation, I am its subject. Call this first-person

access. From the perspective of first-person access, the raw feels of conscious

experience are lived throughenjoyed or suffered (Feigl, 1970, p. 34). Conscious

experience, then, involves the possession of certain brain states, brain states that feel

like something for their owners. And while my neurosurgeon can observe my qualia,in as much as she can observe any neurophysiological property, she only has direct

(first-person) access to her own qualia.

However, it might be objected, does not dual-access theory imply the implausi-

ble consequence that while looking at the surface of, say, a red table, one is not

experiencing the tables surface, but some region of the brain? No, dual-access

theory does not imply this consequence. According to dual-access theory, one is

experiencing the tables surface, and not some region of the brain. The object of the

experiencethat which is being experiencedis the surface of the table. The

experience itself, on the other hand, is a brain state, and one, as the owner of thebrain in question, is in a position to have that experience, i.e. to be the subject of that

neural activity


8/22

232 L. DEMPSEY

Dual-access theory, then, ought not be confused with a higher-order thought

(HOT) or a higher-order perception (HOP) model of consciousness [11]. According

to such views, a first-order state becomes conscious when there is a HOT or HOP

that represents it. I contend, on the other hand, that higher-order thoughts about

ones own qualia are the exception, not the rule. According to dual-access theory,while we do sometimes think about, and reflect on, our own conscious experiences,

we need notand quite often do notthink about, or reflect on, them.

At least two sorts of first-person access should be distinguished here; call them

phenomenal and cognitive access. Phenomenal access is the sort of access had

in first-order conscious experiences. First-order conscious experiences are experi-

ences one is having but not introspecting, i.e. ones that are not being thought about,

reflected on, or otherwise referred to by the organism in question. Conscious

experiences, then, are phenomenally accessed not in the sense of being perceived

or thought about but simply in the sense that one is the subject of them; there need

be no intentional act of inner perception or thought that represents the experience.

This is not to say that we do not sometimes have higher-order thoughts about our

first-order conscious experiences; this, I take it, is an intuitively plausible construal

of introspection and is what I would call cognitive access. We can, it would seem,

not only experience the world but also have thoughts about the experiences them-

selves. Perhaps such cases will inevitably involve introspective mechanisms for

focusing on some states and not others. Introspection, however, is the exception, not

the rule. According to dual-access theory, we do not need to think about or perceive

our conscious experiences in order to have them [12].

Dual-access theorys emphasis on access may remind the reader of the sort ofpositions propounded by Tye (1995, 2000) and Dretske (1995). Such views reject

the need for a HOT or HOP to make a first-order state conscious. What makes a

first-order state conscious is that it is appropriately accessible to processes of

belief-formation, planning, and decision-making. For example, Tye (1995) defends

what he calls the PANIC model of qualia: a quale is a sort of abstract non-concep-

tual intentional content that is poised for use by a cognitive system [13]. On such a

view, then, qualia are a sort of intentional property poised for use in belief-forma-

tion, decision-making, and planning. Tye also advances a mode of presentation

strategy for dealing with the explanatory gap. Put very briefly, he distinguishes

indexical phenomenal concepts from predicative phenomenal concepts. Indexical

phenomenal concepts apply to a percipients own occurrent experiences, e.g., this

pain. Thus, upon emerging from her black and white room, Marythe genius

color scientist who has never seen colorgains new indexical phenomenal concepts;

she is now in a position to say this is what it is like to see red. Tyes response to

the perspectival nature of conscious experiences, then, has its roots in Loars (1997)

mode of presentation account of phenomenal states, and hence, is in the tradition

of Feigls dual-access theory [14].

I agree that qualia are causally relevant in such things as belief-formation,

decision-making, and planning. Indeed, the identity thesis places qualia squarelywithin the causal economy of a sentient organisms nervous system locating them

within the causal web that results in such things as planning and the formation of


9/22


beliefs. It is unlikely, however, that Tye would happily embrace dual-access theory

since central to his account of qualia is a strong form of representational externalism.

As Levine (1997, p. 103) points out, representationalism about qualia can take two

forms. The first holds that qualia are the vehicles of representation, and so, are

intrinsic to the organism. This sort of qualia representationalism is consistent withdual-access theory. The second version of qualia representationalism, the one that

Tye advances, holds that qualia are (abstract) intentional content properties. On this

view, qualia are not intrinsic to an organism; being a function of the distal properties

they represent, qualia are relational intentional properties that abstract away from

the neurophysiological properties of the central nervous system. Qualia, on Tyes

view, are properties of the objects represented in experience, which, in standard

cases of perception, are objects in the external environment. Thus, in the spirit of

Putnams (1975) well known contention that meaning aint in the head, Tye

(1995, p. 151) contends that phenomenology too aint in the head [15].

According to Tye, such a position has many theoretical benefits for dealing with

the mysterious nature of qualia. However, as Levine (1997, pp. 1045) argues, Tyes

qualia externalism does little work for him in resolving the explanatory gap; it is the

modes of presentation strategy that is doing any work and it runs as wellif not

betteron a view that takes qualia to be neurophysiological properties of, and

intrinsic to, the organisms that have them. Indeed, he notes that, Tyes externalism

. . . gets him into serious trouble when it comes to dealing with inverted qualia;

worse than functionalism generally (Levine 1997, p. 109). Since, on Tyes view,

the qualitative character of a conscious experience is a function of the distal

properties it represents, any organism that represents, say, the distal properties thatco-vary with red experiences in humans, must have qualitatively identical experi-

ences. And this is so even if the organism in question has a radically different

neurophysiology, and even radically different sense organs. This, I take it, is highly

implausible and Levine develops a number of inverted qualia thought experiments

to demonstrate this problematic feature of Tyes account (Levine, 1997, pp. 109

12) [16].

Perhaps we do not have to go so far afield to see the problem with qualia-exter-

nalism. Consider the perception of unique hues. All the hues on a hue circle are red,

yellow, green, blue, or some combination of two of them. Some hues are taken to

be more elementary than others: a green that is neither yellowish nor bluish is more

elementary than a yellowish or bluish green. Elementary hues, like a green that is

neither bluish nor yellowish, are unique hues. Interestingly, there is a great deal

of variation between normal observers location of unique hues along the wavelength

spectrum. Subjects consistently identify a unique huefor example, a green that is

neither bluish nor yellowishat differentspots on the spectrum. About this phenom-

enon, Hardin writes,

[U]nder carefully controlled conditions, any individual observer can con-

sistently locate his or her unique green on a spectrum with an error of plusor minus three nanometers. But the average settings for 50 normal observ-

ers spanned a range of almost thirty nanometers from 490 nm to 520 nm


10/22

234 L. DEMPSEY

Most people will see this range of greens as consisting of several dis-

tinguishable hues, ranging from bluish green at one end to a yellowish

green at the other. (1994, p. 564) [17]

A natural way to interpret these results is to take them to reflect subtle but

discernible qualitative differences in color experiences between normal human

observers. In this case, we have the very same distal stimuli systematically evoking

different color experiences in different subjects. How, then, can qualitative character

be a function of the distal properties in question? If the same distal properties evoke

qualitatively distinct color experiences in different subjects, then qualitative charac-

ter cannot be determined by the distal properties alone.

Again, dual-access theory holds that qualia are internal and intrinsic to sentient

organisms. They are a sort of neurophysiological activity that feels like something for

their owners. That they are neurophysiological properties intrinsic to the organism

is, I believe, essential in accounting for their private and subjective nature. Intuitionand experience has it that conscious experiences are, in some sense, private and

subjective, and that they are of a sort that can be introspected with some degree of

privileged access [18]. The neurophysiological properties with which qualia are

co-instantiated are also intrinsic to the organism; only I can feel my pain, just as only

I can be the subject of my own neural activity. Thus, not only is the qualia-body

identity thesis a parsimonious position that gives a straightforward account of the

causal relevance of qualia by locating them within the causal economy of the

organism, it accords well with the private and subjective nature of conscious

experience. As I argue below, the benefits that dual-access theory brings to the

resolution of the explanatory gaps are impressive.

Finally, it should be noted that the sort of access that characterizes the views

propounded by Tye and Dretskeaccess to processes of belief-formation and

planningis not the sort that I have in mind [19]. Dual-access theory is not

concerned with whether or not a quale is accessible to processes of belief formation,

per se. The differences in access that we are concerned with here involve two very

different perspectives on the same physical propertythe direct access had by the

subject of the neural activity in question, and the less direct access had by the

neurosurgeon who is studying that neural activity. The access to my conscious

experiences had by my neurosurgeon is quite different from my access to my ownconscious experiences, and it is this difference in access that will help us resolve the

various explanatory gaps.

4.2. The reductive gap (again)

Let us suspend judgment on the merits of reductive explanations as a general model

of reduction [20]. Even if we allow that there is an epistemic gap in some sense,

there are reasons independent of dual-access theory for denying its importance. As

noted above, we can (and do) have prima facie compelling reasons (arguments fromparsimony, causal efficacy, explanatory force, consciousness-realism) for belief in the

identity of conscious experience and certain sorts of neural activity It should be of


11/22


little surprise that this does not preclude the conceivability of various sorts of dualistic

positions, nor require a definition of conscious experiences in terms of their neuro-

physiological underpinnings: this is, after all, an empirical, a posteriori identity. The

doxastic contexts in which phenomenal and neurophysiological descriptions occur

are, not surprisingly, referentially opaque; one might, for example, believe that one isin pain without believing that ones C-fibers are excited, but this does not imply that

pain is not C-fiber excitation [21]. In other words, the contexts in which phenom-

enal and neurophysiological terms occur obscures the fact that the terms may very

well refer to the same things. One cannot infer a duality of properties from the

phenomenon of referential opacity. As Levine (1993, p. 546) correctly notes, [o]ne

cannot infer from a variety of modes of access to a variety of facts being accessed.

In fact I do not believe that the identities waterH2O and painC-fiber

excitation are different in a way that suggests the latter, but not the former, is false

or somehow problematic. Again, it might be argued that while the macro properties

of water are epistemologically necessitated by facts about H2O, this is not the case

with pain and C-fiber excitation. However, Block & Stalnaker (1999) have convinc-

ingly argued that one could not deduce that water would boil at 100(C from

knowledge of the chemistry of H2O alone. Consider someone who does not know

anything about how water boils; perhaps she does not even know that water is

composed of molecules, or if she does, perhaps she believes that water is composed

of XYZ. Suppose one were to present her with theory T (a complete theory of

physics), and a description (in microphysical terms) of a water boiling situation.

Can she then deduce that ifTis true and a situation met conditions C, then the H2O

would be boiling? No (Block & Stalnaker, 1999, p. 374). For all she knows, wateris composed of XYZ, not H2O, and it is water that boils. Block & Stalnaker

continue:

Perhaps if she were told, or could figure out, that the theory was actually

true of the relevant stuff in her environment, she could then conclude

(using her knowledge of the observable behavior of the things in her

environment) that H2O is water, and that the relevant microphysical

description is a description of boiling, but the additional information is of

course not a priori, and the inference from her experience would be

inductive. (1999, pp. 3745)

The point is that in order for her to deduce from T and the microphysical

description that H2O is boiling, she must already know that H2O is water, and this

she can only learn through experience, that is, a posteriori.

It might be pressed, however, that even if one concedes Block & Stalnakers

point, there is a sense in which appeal to the chemical theory of H2O explains (a

posteriori) the macro features of waterit provides epistemic ascent from the chemi-

cal theory of H2O to the macro features of waterin a way that appeal to the

neurophysiology of the brain does not explain the phenomenal features of conscious

experiences. The identity of consciousness and, say, pyramidal cell activity [22] doesallow for some explanatory ascent. Block & Stalnaker (1999) give the following

example: why has Smith lost consciousness? Well consciousness just is pyramidal


12/22

236 L. DEMPSEY

cell activity and Smith has ingested a substance that causes pyramidal cell activity to

cease. Likewise, that water is H2O allows us to infer from the fact that a certain

volume of water will douse a certain size fire to the fact that the same volume of H 2O

will douse the same fire. But the identity of water and H2O seems to offer more. The

chemical theory of H2O allows us to explain why, for example, water is transparent,colorless, liquid, etc., but neurophysiological theory does not seem to provide us

with an explanation of why pain feels the way it does or, more generally, why one

type of neurophysiological activity feels one way and another type of neurophysio-

logical activity feels another way.

If the identity thesis is true, the qualia-brain relation may very well embody a

part-whole relation in some ways comparable to the water/H2O identity. Consider

that if the identity conscious experiencepyramidal cell activity is true, there is

a sense in which a given conscious experience involves a potentially wide array of

nervous tissue activity; that is, there is a sense in which the relation between the two

is a part-whole relation. Searle (1992) has made a similar claim suggesting that

consciousness is a macro property of the brain as liquidity is a macro property of

H2O. However, the analogy with standard micro-macro relations is far from perfect;

while liquidity is an objective and public phenomenon, conscious experience, as

accessed in the first-person, is not. It is not as if while observing the brain one can

see qualia and, with a closer inspection, the neurons that constitute them. Consider

that what prevents one from directly observing the H2O molecules that constitute

water and account for its liquidity is the size of the moleculesbut it is not the size

of qualia that seemingly prevents them from being directly accessed by the neuro-

physiologist, nor is it the limitations of the perceptual capacities of the human eye.Rather, according to dual-access theory, it is a question of perspective; only the

owner of a brain can directly access its phenomenal properties. In other words,

rather than being a micro-macro reduction as in the identification of water and H2O,

this sort of identity is perspectival. Pain and C-fiber firings are identical not in the

sense that the former is composed of the latter, or that the latter are micro features

of the former, or that the latter fills the causal role definitive of the former, but in

the sense that they are the same thing apprehended or accessed from two different

perspectives. So the claim is not that a pain experience is identical to micro

properties of the brainsay, the micro neurophysiological properties that constitute

C-fibersas water is identical to H2O molecules; instead, a pain experience is

identical to the property C-fiber excitation which is, itself, a macro property of the

brain. In general, then, conscious experiences are identical to certain macro proper-

ties of the brain, properties that can be accessed directly by their owners.

What I have in mind by perspectival identity is quite commonplace. Perspec-

tival identities are discovered, a posteriori, in doxastic contexts which are, initially,

referentially opaque. So, for example, consider a situation in which the same thing

or aspect of a thing is perceived from two or more different perspectives, but where

the percipient does not know that it is the same thing or aspect of a thing. Fred has

recently acquired a new car, a blue Porsche. He has also recently started a new jobin a large office building in a new city. There is a parking lot on both the north and

south sides of the building Fred parks his car on the south side and believes that his


13/22


office faces the north side parking lot. On Freds first day, he notices a beautiful

brand new blue Porsche outside his office window. While Fred is duly impressed

with the aesthetics of this car, he is a little disappointed with the fact that someone

else in the building has a car just like his. Of course, it is not long before Fred

realizes that the car outside his window is his car; in other words, the car he droveto work in and the one he now perceives are identical.

Similarly, there are striking examples of inter-modal identities; these identities

are discovered when it is realized that the same thing or aspect of a thing is being

perceived by different senses. For example, a congenitally blind person that recovers

her sight will have to learn that things that feel square look the way they do, i.e.

square. In this case, the person discovers, a posteriori, that the property she now

perceives visually is the same old property she is used to perceiving tangibly.

Presumably, babies go through a similar process of learning to identify the objects

of sight with the objects of touch, hearing, and so on.

According to dual-access theory, we have a similar situation with qualia. Qualia

are neurophysiological properties of a certain sort, properties to which their owner

can have direct access. But what is being accessed here is the same thing my

neurosurgeon can potentially observe; the difference is one of perspective. An

appreciation of this point, I believe, alleviates any demand for epistemic ascent from

one set of features to another, say, from micro features of the brain to the

phenomenal features of conscious experiences. We would not, I believe, demand the

sort of epistemic ascent Levine describes in the case of boiling waterleaving aside

the issue of whether this ascent is a priori to explain how Samuel ClemensMark

Twain; we do not need to functionalize Mark Twain in order to ground theidentity. What is needed is good reason to believe that Samuel Clemens and

Mark Twain refer to the same person. Likewise for dual-access theory; what we

have in consciousness is a subjects access to conscious experiences that we have

good reason to believe are certain sorts of neurophysiological activity.

If painC-fiber excitation, this is necessarily so, that is, it is true in at least

every nomologically possible world. The claim, then, is that, as a matter of fact, qualia

are certain neurophysiological properties. That we can imagine otherwise (in some

sense) is of little surprise given the obvious differences in the meanings of the terms

involved. Indeed, both terms evoke very different connotations, and Kripke is right

that the identity of water and H2O and pain and C-fiber excitation are not exactly

analogous. Both are empirical identities and both are nomologically necessary; but

whereas waterH2O involves the identification of pretheoretic macro features and

theoretical micro features, painC-fiber excitation involves the recognition that the

same property can be accessed from two different perspectives. This is an important

difference, but rather than showing that the identity fails, it explains why the two

(pain and C-fiber excitation) seem different, why we can imagine one without the

other, and why, I am suggesting, there is no epistemic ascent from the micro

properties of the brain to facts about the qualitative nature of qualia in the way there

is in the case of water

H2O.In sum, we might say that there remains a reductive explanatory gap in the

sense that there is a conceptual gap between the phenomenal language of introspec


14/22

238 L. DEMPSEY

tion and the language of neurophysiology. But this is a very innocuous sense of

explanatory gap. There is no explanatory gap in the sense of a gap between belief

in the identity thesis and the reasons that warrant such a belief. Neither does this

residual gap imply any metaphysical consequences, as Levine would agree, nor does

it demand further explanation; qualia do not admit such explanations, and, I haveargued, this is neither surprising nor troubling.

4.3. Epistemic asymmetries (again)

Dual-access theory has little trouble accommodating these concerns since it posits

different modes of access to the same phenomenon. No one can feel my pain

precisely because no one but me has direct access tois the subject ofmy brain

activity. Such access often provides its owner with a great deal of epistemic authority

even if it falls short of absolute authority. My neurosurgeon, on the other hand, has

a different, more mediated access to my brain. What she is directly acquainted with

is some activity in her own brain, which, in this case, is representing my brain.

In short, the subjective need not be beyond the bounds of the physical sciences;

quite to the contrary, conscious processes are physical processes and conscious

experiences are those processes viewed from the inside, as it were [23]. The

epistemic asymmetries of conscious experience are quite natural and dual-access

theory attempts to account for them in a monistic and parsimonious way.

4.4. Bruteness and incomprehensibility (again)

The first set of bruteness questions, as questions addressed to the proponent of

dual-access theory, can be quickly dispensed with as misplaced. Given that painC-

fiber excitation, there is no explanation of why the two correlate, precisely because,

in fact, there is no correlation. Neither is there any emergence of qualia from brain

activity if emergence implies that the brain is producing something over and above

itself. Thus, we need not puzzle over the mechanism by which conscious experience,

as such, is generated. As Kim (1998, p. 98) correctly points out, [I]dentity takes

away the logical space in which explanatory questions can be formulated. To the

question Why is that whenever and wherever Hillary Rodham shows up, the

Presidents wife also shows up? there is no better, or conclusive, answer than

Hillary Rodham is the Presidents wife [24]. Of course, one might puzzle over

the neurophysiological mechanism that brings about pyramidal cell activity, but such

is a tractable puzzlement that, it would seem, will be dissolved with further research.

With regard to the second set of questions, however, there may remain the

troubling appearance of bruteness. Again, while it is relatively clear how the

neurophysiological properties underpinning pain experiences cause pain behavior,

it might still be asked why those properties feel the way they do; why are they pain

qualia and not, say, color qualia? And why are they, say, sharp and not burning pain

qualia? As Tyndall queries,

[L]et the consciousness of love for example be associated with a right


15/22


handed spiral motion of the molecules of the brain, and the consciousness

of hate with a left-handed spiral motion. We should then know, when we

love, that the motion is in one direction, and when we hate, that the motion

is in the other; but the WHY? would remain as unanswerable as before.

(Tyndall, 1868/1898, p. 87)

Tyndalls concerns here forebode the concerns of the British emergentists; from

knowledge of brain activitythe basal conditionsalone, one will be unable to

predict the type of feeling that will emerge. Even if one knew that the experience of

love co-varies with the right-handed spiral motion of the molecules in the brain and

the feeling of hate with a left-handed motion, one is still left with the question, why?

There may, however, be a lurking dualism here if the question implies that the

brain has both neurophysiological properties and conscious properties as well, and

that the latter are produced by the former. Recall Tyndalls example of an unprob-

lematic empirical association, a magnet deflecting a needle. The mechanism in

this case is clear and there is no lingering puzzlement. But while the magnet example

involves two phenomena in a causal relation, dual-access theory denies this sort of

dualism. The underpinnings of conscious experience are not neurophysiological

states that also have conscious properties; they are the same property instances

accessed either from the perspective of the neurosurgeon or from the perspective of

their owner.

Of course, never having been directly acquainted with the right-hand spirals of

love, one might be (pleasantly) surprised that such spirals in ones own brain feel the

way they do. This case may again remind the reader of Jacksons (1986) Mary. Ourneurophysiologist may have studied the right-hand spiral motions of love for many

years. However, according to dual-access theory, it is only when the right-hand

spiral motions of love happen in her own brain that she becomes the subject of them,

and only then will she finally know what-it-is-like (Nagel, 1974) to be in love.

There probably are, as Huxley calls them, ultimate fact[s] of nature and some

of the facts about the relation between consciousness and brain activity may be of

this sort. I do not believe, however, that there are any troubling brute facts concern-

ing the relationship between qualia and the brain. To see this, consider a case of

what I would take to be a troubling brute identity. Suppose that appeal to the

chemical theory of H2O told us nothing about the macro features of water; the

chemistry of H2O offers us no insight into why water is colorless, liquid, etc. If we

were still inclined to identify water and H2O, this lack of epistemic ascent would be

very troubling. However, I have argued that this micro-macro model of identity is

not appropriate in the case of conscious experience and the brain. In the case of

conscious experience, the identity is posited when it is realized that the same things

are being accessed from more than one perspective. Given that this is not a

micro-macro reduction, the demand for the sort of epistemic ascent had in the

reduction of water to H2O is misguided. Thus, the lack of this sort of epistemic

ascent in the case of qualia and the brain is in no way troubling. Likewise, there isno troubling bruteness in the identification of the Samuel Clemens and Mark

Twain We simply come to realize a posteriori that Samuel Clemens and Mark


16/22

240 L. DEMPSEY

Twain refer to the same person. Similarly, we come to realize, a posteriori, that

pain and C-fiber excitation refer to the same thing; the difference between the

two is one of perspective.

4.5. Differences in appearance (again)

It may be useful to reiterate the unique position of qualia as a species of physical

phenomena. Physical phenomena are, typically, observed through the mediation of

sensory qualia. But one is aware of ones own qualia much more directly; indeed

qualia are the only physical properties that can be accessed in a way that is

unmediated by other qualia. Thus, as a species of physical phenomena, qualia are

unique. But dual-access theory gives a straightforward explanation of any differences

in appearance since, on this view, the brain can be accessed from two very different

perspectives. Since my neurophysiologist cannot be directly acquainted with my

brain, the neural activity that is my conscious experience will seem quite different

from her own conscious experiences.

Recall Ewings argument that the properties are completely different in kind.

He takes himself to be comparing brain states and pains. In effect, however, he is

comparing two of his own conscious experiences: a visual experiencewhich results

from his mediated observations of anothers brainand a pain experience. Pains and

visual experiences are quite different; this, of course, is beside the point. Any

seeming differences between excited C-fibers and pain experiences, according to

dual-access theory, is one of perspective and does not imply a dualistic ontology. The

point, for our purposes, is that my pain experience is not contained in the neuro-physiologistsor for that matter, my ownvisualexperience of my brain. It may be

the object of that visual experience, but one does not feel my pain by looking at it.

For the neurophysiologist to conclude from this that my pain experiences cannot be

brain states would be for her to confuse the object of her observationmy excited

C-fibers/pain experiencewith her own visual experience of my brain (see also

Russell, 1948, p. 229).

In sum, not only is dual-access theory a parsimonious, elegant, and explanato-

rily fruitful hypothesis that faithfully preserves the nature of conscious experience, it

goes quite far in addressing the various explanatory gaps distinguished above.

Although it departs from popular non-reductivist tendencies, its robust resilience in

the face of the explanatory gaps is testament to its utility and intuitive strength.

While many questions remain, I believe we have gone far enough to see that some

version of dual-access theory will be an important element in any plausible natural-

istic account of conscious experience.

Acknowledgements

I would like to thank Ausonio Marras, Jillian McIntosh, John Nicholas, Andrew

Bailey, Chris Viger, Melvin Goodale, Itay Shani, James Sage, Neil Campbell,William Demopolous and the anonymous referee at this journal for helpful com-

ments on early drafts of this paper


17/22


Notes

[1] It is not only proponents of the explanatory gap that resist the identification of qualia with

neurophysiological properties of the human central nervous system; any version of non-reductive

physicalism denies the reducibility of mental properties, although it holds that all events or

particulars are physical. Some non-reductive physicalists construe the relationship between mental

and physical properties as one of supervenience. For instance, Marras (1993, 2000) holds that

qualia, like other mental properties, supervene on, but are not identical to, neurophysiological

properties. The reasons for the widespread rejection of mind-body reduction are varied; this paper

seeks to deal with those who object specifically to the reduction of qualia to their neurophysiolog-

ical co-variants on the basis of the supposed explanatory gap taken to exist between the two sets

of properties. Non-reductive physicalists are motivated more by the supposed multiple realizabil-

ity of the mental: if a mental property is realizable in a wide variety of physically disparate

organisms, then it cannot be identical with any one physical property (see also Hill, 1991).

[2] Other proponents of what I am calling a reductive explanatory gap include Kim (1998), Chalmers

(1996) and Jackson (1993, 1997). For a critique of the sort of reduction scheme used by the

advocates of the explanatory gap, see Block & Stalnaker (1999), Hill & McLaughlin (1999) and

Marras (2002, 2000). The model of reduction advocated by the above writers has many

similarities with the analytic functionalism originally proposed by Lewis (1966) and Armstrong

(1968). On this view, mental properties are given a functional definitionare defined in terms of

a causal roleand are then identified with whatever (physical) property is found to occupy that

role.

[3] This is Hillary Putnams (1975) example of a hypothetical molecular composition of twin

water: waterish stuff that is identical to real water except for its molecular composition.

[4] In Levines words:The story goes something like this. Molecules of H2O move about at various

speeds. Some fast-moving molecules that happen to be near the surface of the liquid have

sufficient kinetic energy to escape the intermolecular attractive forces that keep the liquid intact.

These molecules enter the atmosphere. Thats evaporation. The precise value of the intermolec-

ular attractive forces of H2O molecules determines the vapor pressure of liquid masses of H2O,

the pressure exerted by molecules attempting to escape into saturated air. As the average kinetic

energy of the molecules increases, so does the vapor pressure. When the vapor pressure reaches

the point where it is equal to atmospheric pressure, large bubbles form within the liquid and burst

forth at the liquids surface. The water boils. (1997, p. 549)

[5] There is a problem, however: folk theory and chemical theory have disparate vocabularies. Boil

is not part of chemical theory. How then could the fact that water boils at 100(C be deduced from

chemical theory? The language of the folk theory and of the chemical theory must be bridged.

Hence, bridge principles (Levine, 1993, p. 550) will be required. These bridge principles take

the form of definitions of the terms into the proprietary vocabularies of the theories appealed to

in the explanation (Levine, 1993, p. 551). Thus, for Levine, bridge principles allow the causal

roles definitive of the pretheoretic macro features of the explanadum to be identified with theunderlying chemical mechanisms of the explanans. So, for example, colorlessness is a superficial

property of water, but not a chemical property. To explain why water is colorless in terms of its

molecular structure, then, we need to reduce colorlessness to a property like having a particular

spectral reflectance function (Levine, 1993, p. 551). This particular spectral reflectance function

plays the causal role definitive of colorlessness, and so, since H2O has this spectral reflectance

function, we have an explanation of why water is colorless: colorlessness is a particular spectral

reflectance function; water is H2O and H2O has this spectral reflectance function.

[6] Kim, Chalmers and Jackson, on the other hand, believe that metaphysical consequences follow

from this line of reasoning. Kim (1998), for example, gives essentially the same account of

reductive explanations, and like Levine, he agrees that such a strategy will not work in the case

of qualia. From these sorts of considerations, Kim concludes that qualia are quite likely irre-ducible epiphenomena. But for Kim, unlike Chalmers (1996), such epiphenomenalism amounts to

eliminativism According to what Kim calls Alexanders Dictum genuine (non Cambridge)


18/22

242 L. DEMPSEY

properties must have causal powers and the irreducibility of qualia precludes their causal efficacy.

As Kim puts the point, if you stay with physicalism, you come to[a] choice point: either you retain

supervenient and yet irreducible (that is, nonfunctionalizable) mental properties, say qualia, but

accept their causal impotence, or you embrace mental eliminativism and deny the reality of these

irreducible properties. [But] on Alexanders criterion of what is real, eliminativism and epiphe-

nomenalism both come to pretty much the same thing: mental irrealism. (1998, p. 119)So notonly might this version of the explanatory gap deny the physical nature of qualia, it may even

challenge their reality; the qualities of conscious experience have failed to find a place in the causal

economy of the natural world.

[7] Both quotes are taken from Guzelderes (1997, pp. 478) very informative survey of the historical

and contemporary consciousness literature; Tyndall is there quoted at greater length.

[8] Guzeldere (1997, p. 4) suggests that the puzzlement over the nature of conscious experience is

takenby those who feel such puzzlementto be the result of either (1) the limitations of the

materialist paradigm or (2) our own cognitive limitations. As Guzeldere (1997, p. 48) points out,

Nagel acknowledges the sort of position propounded by McGinn and Tyndall (see Nagel, 1986,

pp. 489).

[9] In a similar vein, I think, Leibniz (1714) points out that if a brain were made as large as a millsuch that one could walk around inside it, one would still not see any thoughts or feelings

thoughts and feelings are not the things we see when we observe a brain.

[10] For contemporary accounts of the mind-body relation that are similar to Feigls dual-access

theory, see Perrys (2001) two-way reflexive theory of sentience; see also Loar (1997, fn. 14)

who advocates a mode of presentation account of first-person experience. Although I may demur

with some of the details, I agree with the general tack of these approaches. My aim here is to

demonstrate how this elegant and parsimonious account of the qualia-body relation dissolves the

various explanatory gaps distinguished above.

[11] For HOP theory see Armstrong (1968) and Lycan (1997); for HOT theory see Carruthers

(2000).

[12] Whats more, I am sympathetic with Perrys skepticism concerning the theoretical benefits a HOT

or HOP theory brings to the mystery of sentience and the resolution of the explanatory gaps.

The amazement that a brain state should feel like something for its owner is not, I believe,

dissipated by positing a HOT or HOP that represents it. As Perry puts the point:One may say that

it is somewhat amazing and mysterious that it can be like something to be in a state. That is

correct, but however amazing it may be, it is true. We gain nothing by pushing the mystery

somewhere else in the mind. The states of our body, often carrying information about the external

world, put our brains in states it is like something to be in. Amazing, but true. The mystery of

sentience does not come when we perceive those states, or think about them, or know them; it

comes when we are in them. (2001, p. 46)If it were the case that a first-order state is only

conscious when there is a HOT or HOP representing it, then I would be inclined to identify

qualiathe raw feels of conscious experiencesnot with the first-order state, but with the HOT

or HOP that makes it conscious. But again, what have we gained by pushing the locus of

experience back to the second-order thought or percept? Is it not just as mysterious and amazing

that the neural activity underpinning a HOT or HOP should feel like something for its owner?

[13] For a review and critique of Tyes PANIC model of consciousness, see Levine (1997).

[14] According to Loar, what Mary gains is a new concept, specifically a phenomenal concept.

Phenomenal concepts are recognitional concepts and they may very well pick out or classify the

same things as certain neuro-functional concepts.

[15] In defense of his qualia-externalism, Tye points to the apparent transparency of conscious

experience. Consider the perception of a red sunset. When we turn our focus to the color

experience, Tye contends, we inevitably end up attending to the external object of the experience,

not something internal or intrinsic to the percipient. This is why, Tye writes,you cannot find

any technicolor qualia, any raw feels, by peering around inside the brain (with or without aflashlight). They simply are not in there. To discover what its like, you need to look outside the

head to what the brain states represent So systems that are internally physically identical do not


19/22


have to be phenomenally identical. (1995, p. 151)In the final section of this paper, I give the

dual-access account of why we apparently do not see any technicolor qualia while peering around

the head. However, space does not permit a detailed critique of Tyes argument from transpar-

ency. Nonetheless, two points are worthy noting here. First, as Levine (1997) points out, one can

recognize the representational nature of sensory qualia without externalizing them. Second, there

are many cases in which conscious experiences are had in the absence of perceiving any externalobjects (e.g. day and night dreams), and indeed, even perceptual experiences can be evoked

without any external objects, as when ones brain is stimulated directly by a neurosurgeon. In

these cases, it is far from clear that there is any transparency in Tyes sense.

[16] For example, Levine (1997, pp. 10912) considers a race of aliens that are neurophysiologically

identical to humans except for the fact that they have color-inverting lenseslenses that invert the

color information reaching the retina. Because, for Tye, qualitative character is a function of the

distal properties it represents, he is committed to the view that these creatures have qualitatively

identical color experiences as humans when presented with the same distal stimuli. And, one

might query, what of creatures that represent these same distal stimuli through the use of radically

distinct sense organs? Arguments from the inverted and absent qualia thought experiments are

much more manageable on a view, like dual-access theory, that construes qualia as intrinsic to theorganism. Levine (1997, p. 105) makes this point when he writes that, if you opt for a view of

qualia as intrinsic physical properties, as the identity theorist does, the inverted and absent qualia

arent so much of a problem. It is quite plausible to maintain that physical duplicates must

share all of their (intrinsic) properties. By hypothesis, my physical duplicate has C-fibers if I do,

and if painexcited C-fibers, then there is little reason to doubt my physical duplicates capacity

for the experience of pain.

[17] Hardins remarks are based on experiments first conducted by Hurvich et al. (1968).

[18] Interestingly, Levine (1997, pp. 11112) argues that Tyes qualia externalism leads to some very

counter-intuitive consequences concerning ones introspective access to ones own qualia. How-

ever, a discussion of these issues goes beyond the scope of this paper.

[19] Nor should we confuse dual-access with Blocks (1997) notion of access consciousness which

he distinguishes from phenomenal consciousness; it is phenomenal consciousness that we are

concerned with here.

[20] Marras (2000, 2002) has noted a number of problems with the reductive explanation model,

especially Kims (1998) version, and has suggested that, once properly understood, a functional

model of reduction is not substantially different from the Nagelian model (Nagel, 1961).

[21] Of course, beliefs about our own conscious experiences represent what I have called cognitive

access to those experiences. And since referential opacity is only relevant for doxastic contexts,

these points about the referential opacity of phenomenal descriptions applies only to cognitive

accessto our beliefs about, and descriptions of, our conscious experiences.

[22] Pyramidal cell activity is Block & Stalnakers (1999) hypothetical reduction base for conscious

experience.

[23] To paraphrase the insightful definition of consciousness in Drevers (1964) A Dictionary ofPsychology. Of course, the visual metaphor is misleading, except, perhaps, in the case of cognitive

access. What is important here is the recognition that some brain states can be accessed from

more than one perspective.

[24] Block & Stalnaker make this point by analogy when they write that [i]f we believe that heat is

correlated with but not identical to molecular kinetic energy, we should regard as legitimate the

question of why the correlation exists and what its mechanism is. But once we realize that heat is

molecular energy, questions like this will be seen as wrongheaded (Block & Stalnaker, 1999, p. 24).

ReferencesARMSTRONG, D. (1968). A materialist theory of mind. London: Routledge & Kegan Paul.

BLOCK N (1997) On a confusion about the function of consciousness In N BLOCK O FLANAGAN


20/22

244 L. DEMPSEY

& G. GULZELDERE (Eds) The nature of consciousness: philosophical debates (pp. 375416). Cambridge,

MA: MIT Press.

BLOCK, N. (2002). The harder problem of consciousness. Journal of Philosophy, 99, 391425.

BLOCK, N. & STALNAKER, R. (1999). Conceptual analysis, dualism, and the explanatory gap. Philosoph-

ical Review, 108, 146.

CHALMERS, D. (1996). The conscious mind. New York: Oxford University Press.CARRUTHERS, P. (2000). Phenomenal consciousness: A naturalistic theory. Cambridge: Cambridge Univer-

sity Press.

DRETSKE, F. (1995). Naturalizing the mind. Cambridge, MA: MIT Press.

DREVER, J. (1964). A dictionary of psychology. Harmondsworth: Penguin Books:

EWING, A.C. (1962) The fundamental questions of philosophy. New York: Collier Books.

FEIGL, H. (1958). The mental and the physical. Minneapolis, MN: University of Minnesota Press.

FEIGL, H. (1967). Postscript after ten years. The metal and the physical: the essay with a postscript.

Minneapolis, MN: University of Minneapolis Press.

FEIGL, H. (1970). Mind-body, not a pseudo-problem. In C.V. BORST (Ed.) The mind-brain identity theory

(pp. 3341). Macmillan: St. Martins Press.

GU

ZELDERE, G. (1997). The many faces of consciousness: a field guide. In N. BLOCK, O. FLANAGAN& G. GULZELDERE (Eds) The nature of consciousness: philosophical debates (pp. 168). Cambridge,

MA: MIT Press.

HARDIN, C. L. (1994). Color and illusion. In W.G. LYCAN (Ed.) Mind and cognition (pp. 555567). MA:

Blackwell.

HILL, C. (1991). Sensations: A defense of type materialism. Cambridge: Cambridge University Press.

HILL, C. & MCLAUGHLIN, B. (1999). There are fewer things in reality than are dreamt of in Chalmerss

philosophy. Philosophy and Phenomenological Research, 59, 445454.

HURVICH, L., JAMESON, D. & COHEN, J.D. (1968). The experimental determination of unique green in

the spectrum. Perception and Psychophysics, 4, 6568.

HUXLEY, T.H. (1866). Lessons in elementary physiology. London: The MacMillan Co.

JACKSON, F. (1986). What Mary didnt know. Journal of Philosophy, 83, 291295.

JACKSON, F. (1993). Armchair metaphysics. In J. OLEARY-HAWTHORNE and M. MICHAEL (Eds)

Philosophy of mind. Dordrecht: Kluwer.

JACKSON, F. (1997). Finding the mind in the natural world. In N. BLOCK, O. FLANAGAN & G.

GULZELDERE (Eds) The nature of consciousness: Philosophical debates (pp. 483492). Cambridge, MA:

MIT Press.

KIM, J. (1998). Mind in a physical world: An essay on the mind-body problem and mental causation.

Cambridge, MA: The MIT Press.

KRIPKE, S. (1980). Naming and Necessity. Oxford: Blackwell.

LEIBNIZ, G. (1965). Monadology and Other Philosophical Essays, trans. by P. & A. MARTIN. New York:

Schrecker.

LEVINE, J. (1983). Materialism and qualia: the explanatory gap. Pacific Philosophical Quarterly, 64,

354361.

LEVINE, J. (1993). On leaving out what its like. In N. BLOCK, O. FLANAGAN & G. GULZELDERE (Eds)

The nature of consciousness: philosophical debates (pp. 543555). Cambridge, MA: MIT Press.

LEVINE, J. (1997). Are qualia just representational? A critical notice of Michael Tyes Ten Problems of

Consciousness. Mind and Language, 12, 101113.

LEWIS, D. (1966). An argument for the identity thesis. Journal of Philosophy, 63, 1725.

LOAR, B. (1997). Phenomenal states. In N. BLOCK, O. FLANAGAN, & G. GULZELDERE (Eds), The

nature of consciousness: Philosophical debates (pp. 597616). Cambridge, MA: MIT Press.

LYCAN, W.G. (1997). Consciousness as internal monitoring. In N. BLOCK, O. FLANAGAN & G.

GULZELDERE (Eds) The nature of consciousness: Philosophical debates (pp. 755772). Cambridge, MA:

MIT Press.

MARRAS, A. (1993). Materialism, functionalism, and supervenient qualia. Dialogue, 32, 475492.MARRAS, A. (2000). Critical notice of Jaegwon Kims Mind in a Physical World. Canadian Journal of

Philosophy 30 137 160


21/22


MARRAS, A. (2002). Kim on reduction. Erkenntis, 57, 231257.

MCGINN, C. (1989). Can we solve the mind-body problem? Mind, 98, 349366.

NAGEL, E. (1961). The structure of science. New York: Harcourt, Brace, & World.

NAGEL, T. (1974). What is it like to be a bat? Philosophical Review, 83, 435450.

NAGEL, T. (1986). The view from nowhere. Oxford: Oxford University Press.

PERRY, J. (2001). Knowledge, possibility, and consciousness. Cambridge, MA: MIT Press.PUTNAM, H. (1975). Mind, language, and reality: Philosophical papers, vol. 2. Cambridge: Cambridge

University Press.

RUSSELL, B. (1948). Human knowledge: Its scope and limits. New York: Simon & Schuster.

SEARLE, J. (1992). The rediscovery of the mind. Cambridge, MA: MIT Press.

TYE, M. (1995). Ten problems of consciousness. Cambridge, MA: MIT Press.

TYE, M. (2000). Consciousness, color, and content. Cambridge, MA: MIT Press.

TYNDALL, J. (1868/1898). Scientific materialism. In J. TYNDALL (Ed.) Fragments of science, vol. 2

(pp. 7590). New York: Appleton & Co.


22/22

consciousness experience reduction and identity

Documents