A
peer-reviewed, edited version of this paper appeared in Vol. 52
No. 2 (2010) of Activitas Nervosa Superior: The Journal for
Neurocognitive Research. That article is available in PDF
form on both this
site and the
ANS site. |
A paper presented at the Tucson III Toward
a Science of Consciousness 1998 conference --- Tucson, Arizona,
1 May 1998.
IMPLICATIONS OF A FUNDAMENTAL CONSCIOUSNESS
Copthorne Macdonald, P.O. Box 2941, Charlottetown, Prince
Edward Island,
C1A 8C5 Canada. Email: cop@copmacdonald.com
Abstract: The author postulates a universe in which mentality is
as fundamental as physicality, explores the implications of that, and presents
hypotheses concerning the evolution and functioning of human cognitive systems
in such an environment. Of the several interpretations of reality which
consider the physical and the mental to be equally real and equally fundamental,
two compatible interpretations are discussed in detail. These are Ervin
Laszlo's biperspectival system theory, and an elaboration of the perennial
philosophy view which incorporates the concepts of algorithm, information,
informational modulation, and evolution. In this latter view, reality comprises
an enduring protophysical, protomental medium modulated by transient informational
patterns. Chance-and-necessity evolution, guided by intrinsic "laws-of-nature"
algorithms, produces systems that may be non-functional, physically functional,
or physically and mentally functional. Given such a reality, the author
concludes that human mentality evolved in bottom-up fashion, with mind-associated
neuronal systems not so much creating mind as organizing a pre-existing
propensity for awareness into useful, functional awareness, and providing
for its modulation by useful information.
The author hypothesizes that discrete, localized occurrences of awareness
accompany the functioning of relatively simple neuronal systems within the
columnar structure of the brain's sensory cortex, and that each of these
systems informationally modulates its associated awareness to create an
elemental quale. Together, the awareness elements of a given sensory modality
constitute a subjective field which, through brain activity not yet fully
understood, becomes topologically related to the body image. The several
superposed fields simulate a unified, multi-modal consciousness and constitute
a global workspace. Selective attention to the qualia in these superposed
fields activates neural correlates which facilitate situation evaluation
and decision making.
I. Introduction
As we assess progress on solving the "hard problem" in consciousness
studies, certain contributions of David Chalmers and Bernard Baars seem
particularly significant. In his recent writings, Chalmers has resurrected
the call of earlier writers (e.g., Russell, 1921; Laszlo, 1972a) to break
with the physicalist view of reality. Chalmers (1995a) proposed "that
conscious experience be considered a fundamental feature, irreducible to
anything more basic," and suggested (1996) that perhaps some form of
constrained double-aspect theory is appropriate. Baars' contribution (1988,
1997a, b) is a comprehensive "global workspace" model of cognitive
functioning based on observed psychological and neurological information
flows. It is a model which, in this author's view, is compatible with a
fundamental mentality and with the hypotheses advanced here.
In this paper I postulate a universe in which mentality is as fundamental
is physicality, explore the implications of that, and present hypotheses
about the evolution and functioning of human cognitive systems in such an
environment. Regarding the hard-problem element in Baars' theory, I address
the dynamics of information transfer in both directions between physically-embodied
and mentally-embodied information.
II. Primal Reality: Physical-Only, or Mental-Physical?
One of the axioms of physicalist science is that the fundamental reality
of the universe has only a physical nature — that reality has no mental
or protomental qualities. We know that research in the highly-physical branches
of science has flourished with this axiom in place. Doesn't this prove that
it belongs there? Not necessarily. No problems arose, I would suggest, because
in the fields of physics and chemistry the axiom was never really challenged.
Where experiments involve overwhelmingly physical phenomena, it simply
doesn't matter whether mentality exists or not. In those fields, the
"everything is physical" assumption had little or no effect on the choice
of experiments, or on the interpretation of experimental results. In trying
to understand what the brain is up to, on the other hand, the assumptions
made about primal reality matter a great deal. Most importantly, perhaps,
they limit the range of hypotheses that are likely to occur to experimenters
and theorists — or to be taken seriously by them if proposed by others.
For a long time there have also been interpretations of reality that see
the physical and the mental as being equally real and equally fundamental.
Forms of this perspective appeared first in the perennial philosophy
traditions, later as dual-aspect monism and the biperspectival
systems view, and most recently as panexperientialism.1
It is a way of looking at things that has been advocated
for some time as a possible basis for solving the mind-body problem (Russell,
1921; Globus, 1976).
Globus (1973, p. 154) articulated the view this way: "mind is but one
aspect of a fundamental neutral reality with matter being a second aspect,
both aspects having equal importance, as two sides of a coin." Wald (1988,
p. 9) used these words: "[Consciousness] is not some iffy phenomenon that
we just project on reality; it is at the base, at the foundations." Wald
also quoted Pauli:
"To us...the only acceptable point of view appears to be one that
recognizes both sides of reality — the quantitative and the qualitative,
the physical and the psychical — as compatible with each other, and can
embrace them simultaneously. It would be most satisfactory if physis
and psyche (i.e., matter and mind) could be seen as the complementary
aspects of the same reality." (p. 11)
Rensch (1971, p. 297) said:
"there is no contrast between mind and matter. We must recognize that
all "matter" is protopsychical in character."
Like the statements above, most statements about psycho-physical reality
tell us little about how fundamental consciousness might actually work.
System theorist Ervin Laszlo's biperspectival systems theory (1972a)
is more specific. Laszlo, too, considered mentality to be fundamental. But
he also held that specific expressions of mentality occur in a systems context,
and that each system experiences "sensations appropriate to the organization
of the system" (1972a, p. 172). Just as Laszlo saw consciousness going all
the way down, he also saw systems going all the way down. In the view he
articulated, the universe is a hierarchy of "natural systems" with the systemic
structures at one level in the hierarchy being components in the systems
at the next, more complex, level. His hierarchy included atoms, molecules,
inorganic crystals, organic cells, multi-cellular systems within organisms,
and whole organisms. Individual systems at all levels are "biperspectival".
That is, each system can be experienced objectively from the outside as
a physical entity. But each is also capable of experiencing aspects of its
own functioning. Laszlo ascribed subjectivity to systems as simple as atoms
and molecules, and speculated that an atom would experience major events
such as an electron jumping from one orbit to another, or the fission of
its nucleus.
Laszlo also called attention to those much more complex systems which
play a subjective role in cognition. He called these latter systems "natural-cognitive"
systems, and said of them:
"[Natural-cognitive systems] are . . . 'biperspectival': They are
single, self-consistent systems of events, observable from two points of
view. When 'lived'. such a system is a system of mind-events, viz., a 'cognitive
system'. When looked at from any other viewpoint, the system is a system
of physical events, i.e., a 'natural system'. The physical and mental sets
of events are correlates . . ." (1972a, p. 154)
In such a cognitive system there would be closed, inaccessible subjectivities
within each component of the system — each atom, molecule, and cell — as
well as the "mind-event" subjectivity associated with the system as a whole.
When we contemplate psycho-physical theories such as Laszlo's, it is important
that we don't anthropomorphize. Although all physically eventful systems
will also be mentally eventful, the mental events of most systems are not
going to be anything like human mental events. Nor are they likely to be
useful. This is obviously true of the physical utility of systems.
If I take a handful of electronic parts at random, interconnect them in
some unplanned way, and apply a voltage between two points, something electrical
will probably happen. A current may flow; parts may heat. But nothing particularly
useful is likely to happen. Only a tiny percentage of possible systemic
structures and energizing arrangements allow interesting and useful physical
happenings. We must expect the same to be true of the mental aspect of physical
systems. Even if a system has been carefully designed for physical utility,
there is no reason to suspect that its mental aspect will serve any sort
of useful function. The analytical challenge is to find out what sort of
physical arrangements give rise to useful mentality. Later in this
paper I share some of my own analysis, and discuss what I consider to be
the systemic roots of the human "global workspace" mental environment.
Laszlo's theory gives us a rough sense of mental happenings at the whole-system
level, but very few details. Fortunately, a recent elaboration of the perennial
philosophy view — one that incorporates the concepts of algorithm, information,
informational modulation, and evolution — allows us to see more. Laszlo's
theory and this other view are based on similar assumptions about primal
reality, and both focus on the role of systems. But this new perspective's
kit of conceptual tools helps us to explore more deeply the why and
how of psycho-physical systems, and to better understand the processes
going on within them.
The perennial philosophy perspective was first introduced to many
English-speaking readers by Aldous Huxley (1945), but the view has long
been espoused by Vedanta, Taoism, the Zen and Dzogchen branches of Buddhism,
and Christian mysticism. It is "a view which holds that underlying the transient,
ever-changing realm of manifest existence is an eternal unmanifested Ground,
a protophysical, protomental oneness that interpenetrates existence and
enables it to be." (Macdonald, 1994, p. 136)
The ancients were able to apprehend this perspective intuitively, but
had difficulty expressing it clearly in words because they lacked certain
key concepts that we now have. The present "information age" or postmodern
refinement of the perspective had to wait until these concepts emerged and
became part of our cultural vocabulary — concepts like medium and message,
carrier and modulation, algorithm and information. It had to wait, for instance,
until Claude Shannon (1948) demonstrated that the fuzzy concept of information
could have a solid, quantifiable meaning. It had to wait until DNA research
in the 1950s showed that organisms and other physical structures are in
fact informational structures. It had to wait until the role of algorithms
in information processing became clear in the 1960s and 1970s, and until
ideas about parallel processing began to emerge in the 1980s. In essence,
the interpretation is this:
Reality consists of an enduring medium modulated by transient informational
patterns.
- The medium has a physical aspect, a mental aspect, and an algorithmic
aspect.
- Physically, the primal medium is energy or proto-energy — the ground
of the physical universe.
- Mentally, the primal medium is awareness or proto-awareness — the ground
of mind and subjective experience.
- Algorithmically, the medium is the home of "laws of nature" algorithms
which, during the life of the universe, allow mental/physical potentials
to become actualized. These algorithms, these laws, are the intrinsic
rules that guide physical, chemical, geological, and biological change.
It is the moment-to-moment functioning of these algorithms that forms,
patterns, and modulates the primal medium with information — creating,
as it does, that hierarchy of systems we call the universe. In information
processing terms, the universe is equipped with built-in recursive algorithms
which repeatedly take the informational situation that exists at this
instant and transform it into a new informational situation in the next.
(Macdonald, 1994, p. 136)
At t = 0, the instant of the Big Bang, our universe is generally conceived
as just the medium with no, or almost no, informational patterning. Within
a small fraction of a second after t = 0, however, the informational patterning
or modulating began (Barrow & Silk, 1980). This information-creating,
system-building process has been described for the early universe by Weinberg
(1988), for the later universe by Laszlo (1972a, 1972b, 1987), and overall
in narrative form by Swimme and Berry (1992). A hierarchy of natural systems
evolved in response to the guidance offered by those intrinsic algorithms.
In this view, the physical universe is seen to be an informational patterning
of energy. At the submicroscopic level that patterning appears as varieties
of energy/matter quanta, and as atomic and molecular structure. At micro-,
meso-, and macroscopic levels it appears as the space-time patterning of
those components in complex geological, biological, and astronomical systems.
The enduring reality is the energy itself (it cannot be created or destroyed),
but what makes the universe so interesting is the ever-changing informational
patterning which energy undergoes as evolution proceeds.
III. Information, Awareness, Qualia, Mind, and Attention
The essence of information is difference, or as Gregory Bateson
put it: "any difference which makes a difference" (1975, p. 381). Plato
may have imagined disembodied information, perfect patterns existing all
by themselves on some ethereal plane. But real-world information is not
like that; differences that make a difference must be differences in something.
Information must have its medium or carrier. So information isn't a thing-in-itself,
it is a pattern of significant differences impressed upon some substrate
or medium that serves as its carrier. There are both encoded information
and embodied information. Examples of encoded information include written
language, DNA, and the ones and zeros of computer data. Examples of embodied
information include the shape of an ocean wave, the structural and functional
organization of a living organism, and the details of a conscious experience.
Viewing physical existence as informationally-patterned energy meets little
resistance these days. Mathematician Rudy Rucker has said: "It is now considered
reasonable to say that, at the deepest, most fundamental level, our world
is made of information. . . . For postmodern people, reality is a pattern
of information, a pattern in fact space" (1987, p. 31). Physicist John Wheeler
put it this way: "all things physical are information-theoretic in origin"
(1994, p. 296), and added, "Tomorrow we will have learned to understand
and express all physics in the language of information" (1994, p. 298).
In addition to being a carrier of physical information, a psycho-physical
primal reality is also a carrier of mental information. We have labels for
its mental-carrier aspect: awareness, sentience, pure subjectivity, consciousness
without content.2 I use
the term awareness because there are few one-word alternatives,
and because much of the perennial philosophy literature
uses it.3 Beyond labeling this carrier,
we can refer to its roles and functions: Awareness and energy are the two
faces of the primal reality, and in the same sense that energy is the enabler
of physical activity, awareness is the enabler of mental activity. Awareness
is the ground, medium, and carrier of mind. Awareness is what permits conscious
experience. Awareness is the subjective capability that is present during
ARAS (ascending reticular activating system) arousal. Awareness is the sentient
medium that when modulated by neuronally-generated information becomes mental
qualia, mind with informational content. But because awareness is primal
and unique, our powers of definition are limited. As with other one-of-a-kind
aspects of primal reality (energy, time, space), a detailed analogic definition
of awareness is not possible.
Traditionally, definitions of primal entities have left much to be desired.
Asked to define time, Einstein is supposed to have said: "Time is
what clocks measure." A widely-accepted definition of energy is:
"Energy is the capacity to do work." About awareness we might say:
"Awareness is the capacity to present information subjectively." Each definition
is saying something interesting about the primal entity it attempts to define,
but each falls short of letting us look at the intrinsic nature of that
entity. To me, this difficulty in defining awareness is itself strong evidence
that this aspect of reality which I'm labeling awareness — like those
other aspects: energy, time and space — is fundamental,
not derivative.
In the view presented here, awareness and its informational modulations
are intimately associated. This intimacy is analogous to the intimacy between
the ocean and its wave modulations or a radio station's energy carrier and
its program modulations. In this view there is no observer/observed duality,
no "ghost in the machine." There is no experiencer separate from experience;
there is just experiencing. The casual observer of mind does see a subject/object
duality, but adepts in advanced perennial philosophy traditions such as
Zen and Dzogchen have seen through the apparent duality and have become
cognizant of the inherently non-dual nature of mental experience.4
Varela also commented on this:
"One of the originalities of the phenomenal attitude is that it does
not seek to oppose the subjective to the objective, but to move beyond the
split into their fundamental correlation." (1996, p. 339)
Those accomplished meditators and Western phenomenologists who have paid
the price in time and effort to, in Wilber's words, "become adequate to
the postformal data". represent a "validating community of competent subjects"
who attest to this.5
Before proceeding, I'd like to clarify my use of three other terms. Qualia
are awareness-associated informational artifacts. They are components of
the informational totality which constitutes conscious experience. They
are specific instances of informationally-modulated awareness. They are
mind content. Edelman has said:
"Qualia constitute the collection of personal or subjective experiences,
feelings, and sensations that accompany awareness. They are phenomenal states
— "how things seem to us" as human beings. For example, the "redness"
of a red object is a quale. Qualia are discriminable parts of a mental scene
that nonetheless has an overall unity. They may range in intensity and clarity
from "raw feels" to highly refined discriminada." (1992,
p. 114)
In another sense, qualia are mental metaphors that symbolize the modulating
stimulus, or are elements of a mental analog of some perceived reality (Jaynes,
1982). For example, specific odors are mental metaphors for specific air-borne
molecules. And visual experience is a reasonably accurate mental analog
(map) of the optical scene projected on the retinas.
Mind is the space-like awareness environment in which qualia
appear, the subjective global workspace, the composite experiential field.
Attention is a condition of mind and brain marked by heightened,
and usually selective, noting of qualia. Research tells us that selective
attention is not caused by varying the intensity of awareness — which is
simply present during periods of arousal and not present during deep sleep
— but by selectively gating neuronal information.6
The usual human pattern is to attend intently to one
quale or aspect of a quale at a time, although wide-focus, multi-qualia
modes of attending can be learned (Fehmi and Fritz, 1980).
IV. Why evolve a mind?
I agree with Chalmers when he said, "For a satisfactory theory, we need
to know more than which processes give rise to experience; we also need
an account of why and how. A full theory of consciousness must build an
explanatory bridge" (1995b). The model of conscious functioning that my
own mind-watching and literature-review activities have led me to adopt
is a theater model, similar to, and I believe largely compatible with, Bernard
Baars Global Workplace Theory (Baars, 1988, 1997a, b; Newman and
Baars, 1993). What I propose to contribute to that view is some insight
into why and how the global workplace came into existence,
and perhaps a few fresh thoughts about its functioning.
Let's begin with the key question posed in Vol. 1, No. 2 of the Journal
of Consciousness Studies: "Why, in principle, should a neuronal
system of any degree of complexity give rise to the phenomenal experience
of consciousness?" My answer has two parts: If we start with radical
physicalist assumptions about the nature of reality, then there is no
reason why, "in principle". a neuronal system should give rise to conscious
experience. If, however, we start with the assumption that primal reality
is as described in this paper, then the arising of conscious experience
is not astonishing at all. It's just what we might expect. If reality is
this second way, then the role of the neuronal system is not to mysteriously
create awareness and mind from alien substance. Rather, it is to
organize a pre-existing propensity for awareness into useful, functional
awareness, and provide for its modulation by useful information. Again we
face the utility issue. If awareness is as primal and ubiquitous as energy,
then it will be present in every system. But whether or not it plays a functional
role will depend on how a particular system has been configured, and the
nature of its connections to the world outside it.
It is quite possible that during pre-biological evolution (the cosmological
and geological phases of evolution) awareness played no functional role.
It is clear, however, that at some point during biological evolution, awareness
was harnessed and put to work. If, today, we humans were given the task
of designing systems that have useful mental characteristics, we
quite literally would not know where to begin. Yet evolution — with its
slow, plodding, chance-and-necessity genius — did a magnificent job of it.
As I see it, this was possible because the medium on which the cosmic
algorithms have been operating is a mental-physical medium, not just a physical
one.
Early in the evolution of living things, organisms exhibited sensitivity
to their environments, and some were able to respond to environmental changes.
Many types of plants align themselves to maximize their exposure to light.
Paramecia move away from irritating stimuli. These behaviors appear to most
scientists to arise from totally physical, reflex-like mechanisms. They
feel that subjectivity and mind play no functional role, and this may well
be true. It may even be true of amphibians. In the classic Lettvin, J. et
al. (1965) study of "What the frog's eye tells the frog's brain".
the frog's eye is reported to have different types of retinal sensors that
give rise, quite automatically it seems, to a limited set of stereotyped
behaviors. If a small dark object passes across the frog's field of vision
(a fly, perhaps?), the frog's tongue reflexively darts out. If the overall
light level suddenly drops (the shadow of a hawk, perhaps?) the frog reflexively
jumps off the lily pad. Whether or not these organisms have a functional
consciousness may become clear when we finally understand how human
mentality works at the neural level.
As evolution progressed, species proliferated and ecosystems became more
complex. Increasingly intricate forms of animal life emerged to take advantage
of newly created environmental niches. Increasingly sophisticated sensory
systems evolved. New survival opportunities opened up; but so did new threats
to survival. As a result of all this, evolutionary pressure arose for better
situation-analysis and decision-making capabilities.
With just one perceptual mode (say chemical sensitivity or taste) and
a limited number of action modes (say eating and flight), purely physical,
reflex-type control of behavior would appear to be adequate. But in organisms
equipped to receive several different kinds of highly-detailed sensory information
simultaneously, and to respond in many different ways, the demands on the
control system increase dramatically. To avoid behavioral chaos or gridlock
from competing information, sophisticated analysis and decision-making systems
were needed, and eventually evolved.
Artificial intelligence research has shown that it is not easy to sort
out the relevant from the irrelevant, or even to make figure/ground discriminations
using physical-only approaches (Hurlbert and Poggio, 1986). I am suggesting
that mentality — and selective attention in particular — was evolution's
way of solving this problem. I am not saying that it is impossible, in principle,
to perform these same tasks using only the physical aspect of systems and
computational techniques. Rather, I'm hypothesizing that this is not what
evolution did. If we human designers were given the task, we would be forced
to take an all-physical approach (the only one with which we are currently
familiar), and given sufficient time and resources we might eventually succeed
in solving the problem that way. Evolution, however, had another design
option, one not yet open to us: the option of incorporating mentality as
well as physicality into its designs. This, of course, is not a new idea.
Baars (1997a) notes William James's comment: "The study . . . of the distribution
of consciousness shows it to be exactly such as we might expect in an organ
added for the sake of steering a nervous system grown too complicated to
regulate itself" (James, 1890/1983, p. 141). Theorist of evolution Harry
Jerison put it this way: "I regard the mind and conscious experience as
constructions of nervous systems to handle the overwhelming amount of information
that they process" (1973, p. 4).
Evolution's mental-physical approach seems to have been this: Create neuronal
systems that generate mental metaphors or analogs of the immediate physical
situation, and bring them together in one mental "space." Combine this with
a selective attention mechanism which allows the superposed mental fields
to be scanned for qualia that have survival or reproductive significance,
and arrange for the neuronal correlates of attended-to qualia to become
available for unconscious computational processing.7
In humans, if the processing deems the quale to be extremely significant
it will occasionally give rise to an automatic reaction, as when someone
jumps immediately to save a child in danger. Usually, however, the computational
processing simply suggests a course of action. It does this by causing
a thought, feeling, or emotion to appear in the mind along with the information
already present there. A third possibility arises when the processing decides
that the quale being attended to is not significant. In that case, an unconscious
instruction restarts attentional scanning.
In this view, the conscious field is the great simplifier. The creation
of a mental "workspace" allows large amounts of relevant and irrelevant
information to be brought together in one subjective arena. Selective attention
then allows that mass of data to be rapidly surveyed in serial fashion.
Neuronal correlates of items attended to are checked computationally for
relevance. Different kinds of relevance cause different kinds of data-processing
outputs to appear in the mind: mental images; thoughts; and feelings
of pleasure, pain, fear, anger, hate, or tenderness, for example. These
newly-arisen qualia are themselves then available for possible selection
by attention, and if selected, their neuronal correlates would be
used as input data for further processing. At the end of all the processing,
the ultimate behavioral decision is frequently accompanied by a mental correlate
of its own — a YES feeling, a NO feeling, fear, anger, etc.
This kind of analysis-and-control system is flexible. Because evolution's
behavioral suggestions — lust, fear, hunger, anger, a liking for sugar,
etc. — are presented mentally, they are not hard-wired action imperatives.
Priorities can be accommodated; "Flee the tiger rather than grab the
fruit". And learning can override evolutionary messages; "I'm
already overweight, so I'll ignore the impulse to have dessert." Through
our immersion in culture we acquire a learned hierarchy of values which
can, in various circumstances, override evolution's default hierarchy. If
our learning has been appropriate to our reality, then we will behave appropriately
and wisely in a much wider range of circumstances than if our control system
had been hard wired in another era.
V. Some Neurological Speculations
Postulating that we live in a two-aspect, biperspectival universe allows
us to take seriously the possibility that for a relatively primitive mentality
to come into existence, an extremely complex brain is not needed. If subjectivity
is fundamental, then we should expect that relatively simple forms of mind
would require only relatively simple systems for their arising. It appears
that even in the human brain, awareness may not arise as one unified whole,
but through the integration of many localized instances of awareness, each
of which is associated with the functioning of a relatively simple local
system.
Although human awareness seems unified, research during the past
few decades indicates that it is not. Hebb (1980, p. 40), in referring to
the split-brain patients of Bogen, Gazzaniga and Sperry, notes that after
the two brain hemispheres were separated surgically "a patient might seem
to have two minds, a left-hand and a right-hand mind." MacLean (1977, p.
313) saw "three mentalities." He felt that each part of the "triune brain"
(reptilian brain, limbic system, and neocortex) has "its own subjectivity."
Jackendoff (1990, p. 52) saw yet another "disunity in awareness" — a disunity
in which each sensory modality has its own separate awareness.
I am suggesting that the separate subjective fields associated with vision,
somatosensory experience, hearing, smell, and taste are each made to relate
topologically to the body image by processes of arrangement and binding
not yet fully understood. The effect is a superpositioning of the individual
fields. They overlay and overlap much like multiple transparencies laid
on an overhead projector, with all five sensory fields occupying roughly
the same subjective space.8 Together,
the superposed fields simulate a unified multi-modal consciousness,
and constitute a subjective global workspace.
I am also suggesting that even within a single brain region or sensory
modality, awareness may not be unified. Let us think for a moment about
the discrete nature of the information involved in visual perception. Although
human visual experience seems smooth and continuous, we know that the information
which gives rise to it is actually discrete, segmented, elemental. Being
derived from the outputs of discrete retinal neurons, visual experience
is like a computer image or newspaper picture in that it contains a limited
number of visual elements. Visual experience seems continuous because
the elements are tightly packed, and because there are so many of them.
But it is not continuous. The seemingly smooth and continuous experiences
of sound and touch also originate in impulses from discrete sensory neurons
in the cochlea and skin. If the information that fills the various sensory
fields seems continuous but isn't, why assume that the awareness associated
with that information is continuous? I am suggesting that it is more reasonable
from an evolutionary and systems point of view to assume that each element
of conscious data is associated with its own element of awareness.
My hypothesis is that in the visual, auditory, and somatosensory cortex
of the human brain there exist a multitude of relatively simple neuronal
systems, each of which organizes the medium's inherent subjective capacity
into a functioning elemental awareness. If an appropriate neuronal signal
is received from an external source, each of these mind-element systems
also informationally modulates its elemental awareness, creating in the
process an elemental quale — a pictorial element in the case of visual perception,
part of an auditory experience, or a localized sensation in the somatic
sensory field. The binding and orienting problems still need to be solved,
but it may turn out that what is being bound and oriented are a large number
of quite small elements of awareness — each with its associated informational
modulation.
The visual system has been more extensively studied than the auditory
or somatosensory systems, and to support "the involvement of early
parts of visual cortex in visual consciousness." Baars (1997a) presented
four "convergent lines of evidence" (p. 68):
First, when Area V1 is lost, people report a loss of visual conscious experience,
though they can still "guess" at the objects their eyes are looking at.
Second, when the early visual areas are stimulated by a gentle current,
people report conscious visual flashes (phosphenes). Third, when people
are conscious of a visual object, we can see the early visual areas "light
up" in PET scans, indicating a distinct increase in neural activity. Fourth,
recording of single cells in visual cortex indicates that there is a difference
between the conscious and unconscious flows of stimulation (pp. 100-01).
Cortical areas A1 and S1 play roles in auditory and somatosensory perception
analogous to V1's role in vision. The bilateral destruction of A1 produces
cortical deafness (Aitkin, 1990), and the destruction of S1 results in the
inability to consciously perceive stimuli at the body surface (Schmidt,
1986). Thus, it seems likely that A1 and S1 are where the space-like fields
of auditory and somatosensory awareness and qualia are generated — although
secondary processing areas might also be involved.
The neural columns which are present in these sensory processing areas
seem likely candidates for those awareness-organizing, awareness-modulating
subsystems mentioned above. One suggestive piece of data is that the observed
resolution of visual data in V1 is similar to column spacing. F.T. Hambrecht
(1992) electrically stimulated the foveal region of V1 and determined that
phosphenes produced by simultaneous stimulation through two electrodes 500
microns apart appeared as two separate phosphenes, but as just a single
phosphene when electrodes were 250 microns apart.
Another reason for highlighting these neural columns is that cortical
levels 2, 3, and 4 appear to be involved in the processing of sensory data,
and levels 5 and 6 appear to be involved in arousal and the presence or
absence of consciousness.9 This
suggests the possibility that neurons in layers 5 and 6 may be involved
in organizing awareness tendencies into useful awareness, and that neurons
in the middle layers may be involved in modulating that awareness with sensory
data and "sensory-like" imagined or remembered data.
It is also possible to describe the situation from Laszlo's "biperspectival
system" point of view. From that perspective, those small awareness-organizing
neuronal systems are subsystems of the overall "global workspace"
cognitive system, and their functioning is an integral part of the larger
system's functioning. As modulating signals from the computational environment
are processed by the columnar subsystems, subsystem physical states constantly
change — elemental physical events occur. Those physical changes
are accompanied by correlated changes in subsystem subjective states — elemental
mental events occur.
The many mind-element subsystems, together with those brain subsystems
responsible for their topological organization, constitute a single "natural-cognitive
system" whose interior state is the subjective global workspace.
Human consciousness is this system's self-experience.
VI. Next Steps
What's next? What can be done to investigate bottom-up hypotheses such
as those put forth here? How can we test their validity and determine their
worth? A few thoughts:
- First, previous experimental work could be reconsidered with the present
set of ideas in mind. Would this, in at least a few situations, lead to
a different interpretation of the original data? Is there previous experimental
work that clearly refutes the speculations and hypotheses put forth in
this paper? Is there work that lends support or confirmation?
- Could an experiment be devised to temporarily block arousal in a
portion of V1 without interfering with information processing activities
in the blocked region? How would this affect subjective experience? And
what would the change in subjective experience tell us about the validity
of the ideas presented here?
- Obviously, it is important to continue work on the binding problem,
and to search for the mechanism which aligns whole fields of awareness
elements with the body image. Equally obvious is the importance of lesion
analysis and brain-scan technology in shedding light on brain/mind correlations.
The eventual task will be to "reverse-engineer the wetware" to determine,
in detail, how neural functioning actually does give rise to subjective
experience. But first we need to know that we are heading in the right
direction. We need experiments that help determine whether or not consciousness
really is a bottom-up phenomenon, a fundamental feature of the universe.
Notes
1 For a discussion of panexperientialism see de Quincey (1994). Back
to text.
2 Can we really talk about consciousness without content, awareness without
informational modulation, mind without qualia? Absence of mind content is
not part of our everyday experience, but accomplished meditators approach
this condition. They find that during prolonged periods of meditation, mind
content drops toward the asymptotic limit of no content. They also find
that awareness remains present, irrespective of the level of mental information.
At some point in their practice, many advanced practitioners experience
a cognitive shift in which awareness becomes figure rather than ground,
and is thereafter recognized as a tangible reality in its own right. Back
to text.
3 I do realize that the term is also used in other senses — Chalmers" use,
for example (1996, p. 28). Back to text
4 Varela has suggested that both Western Phenomenology (1996) and Buddhist
meditation (Varela, et al., 1991) are useful techniques for the serious
investigation of conscious experience. Wilber (1997a, b) and I (Macdonald,
1996) have made similar suggestions. Disciplines that I have found particularly
fruitful are the Vipassana and Dzogchen varieties of Buddhist meditation,
and the Western practice called Open Focus (Fehmi and Fritz, 1980). Back
to text.
Where appropriate, researchers will have to engage in various injunctions
that transform their own consciousness if they are to be adequate
to the postformal data. You cannot vote on the truth of the Pythagorean
Theorem if you do not learn geometry (the injunction); likewise, you cannot
vote on the truth of Buddha Nature if you do not learn meditation. All valid
knowledge has injunction, apprehension and confirmation; the injunctions
are all of the form, "if you want to know this, you must do this" — and
thus, when it comes to consciousness studies itself, the utterly obvious
but much-resisted conclusion is that certain interior injunctions have to
be followed by the researchers themselves. If we do not do this,
then we will not know this (1997a, p. 91). Back
to text.
6 Newman and Baars (1993) report that "virtually all information conveyed
to the cortex from visual, auditory, and somatosensory pathways is relayed
through the thalamus" and that "gatelets" in the reticular
nucleus of the thalamus regulate the "flow of information from the
thalamus to the cortex." They report that these gatelets are opened
and closed in response to control signals from various regions of the cortex.
Back to text.
7 A number of researchers have presented results that link conscious experience
and the attentional process to specific physical brain correlates. For example,
Wurtz, Goldberg, and Robinson, reporting on their primate research, said:
If the monkey is alert, but not attending to anything in particular, the
response of the nerve cells in [the posterior parietal cortex] is relatively
uniform. When the monkey begins to attend to some object, however, the nerve
cells in the posterior parietal cortex that are related to the object because
it is in their receptive field begin to discharge more intensely. . . .
We do not know how the enhancement arises, and in the absence of this knowledge
it is tempting to say that the enhanced response amounts in itself to visual
attention. It remains quite possible, however, that the enhancement is only
a correlate of visual attention (1982, p. 124).
It is also possible to pay attention to visual attributes other than position,
and to detect, in the secondary visual processing areas, physical correlates
of that kind of attending. As Corbetta, Miezin, Dobmeyer, Shulman, and Petersen
found:
"attention to basic visual attributes such as shape, color, or velocity
appears to influence . . . physiological measures of visual processing.
. . . Physiologically, neural activity is increased in extrastriate regions
specialized for processing information related to the selected visual attribute"
(1990, p. 1556). Back to text.
8 Should you wish to investigate this for yourself, I have elsewhere (Macdonald
1993) described a little experiment:
"If I look straight ahead and move my hands around to find the edges
of the visually-active part of the field, I conclude that it's about one
unit high and three or four wide. If I then put a bottle of perfume under
my nose, the experience of odour fills much of this same field — being most
intense in the centre, less so at the edges. If I next bite into a piece
of fruit and pay attention to my experience of taste as I chew it, I find
that taste occupies a more sharply defined zone than odour. Taste sensations
appear in a horizontally-oriented oval located below the centre of visual
data. Touch, body sensations, and sounds also appear in the awareness field,
sometimes extending beyond the edges of the visual data. The location of
most body feelings and sensations is sharply defined, while the direction
of most sounds is just roughly indicated " (pp. 25-6). Back
to text.
9 See, for example, Livingstone and Hubel (1981). Back
to text.
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