Is Consciousness Only a Property of
Jonathan CW Edwards, University College London
The text below is the basis of a paper published in the April/May 2005
issue of Journal of Consciousness Studies. It represents the most recent formal
version of an idea which has evolved at this
internet site since October 2002. First posted summer 2004. Revised February 2005.
Further comments on the single cell approach to consciousness are being
We perceive colour, shape, sound and touch 'bound' in a single experience. The
following arguments about this binding phenomenon are raised:
1. The individual signals passing from neurone to neurone are not
bound together, whether as elements of information or physically.
2. Within a single cell, binding in terms of bringing together of information is potentially
feasible. A physical substrate may also be available.
3. It is therefore proposed that a bound conscious experience is a property of an
individual cell, not a group of cells. Since it is unlikely that one specific
neurone is conscious,
it is suggested
that every neurone has a version of our consciousness, or at least some form of sentience.
5. However absurd this may seem it is consistent with the available evidence;
arguably the only explanation that is. It probably does not alter the way we
should expect to experience the world, but may help to explain the
ways we seem to differ from digital computers and some of the paradoxes seen
in mental illness. It predicts non-digital features of intracellular computation,
for which there is already evidence, and which should be open to further experimental
The binding problem
The binding problem may be defined as the absence of an explanation for the ordered
integration of many and varied sensory elements into a single subjective experience.
Recent accounts of the importance of this problem to theories of consciousness are given by
Chalmers (1995) and by Seager (1995). The problem is a complex of related problems
(Hardcastle, 1994; Revonsuo and
Tarkko, 2002), two of which I will distinguish, although they are entangled. The first,
which I will call the information problem, is that of the nature of the pathways that bring
signals arising at different sites in the brain together as information. (Drawing the flow
chart without worrying about the physics.) The second, which I will call the physical
substrate problem, is that of finding a substrate at the fundamental physical level
which might support a subjective experience in which
many elements are bound into a seamless whole.
There are further complexities. Binding of experiential elements is full of paradoxes
and illusions, most clearly seen in
brain disease, but also by normal perception. Experience is like a questionnaire about
the world, with answers about both objects and their relations partly filled in.
My aim is not to explain these anomalies, but to find a starting point for binding
being possible. However, the anomalies suggest that experience uses a language quite
different from that used by a television to form an image, in keeping with
the sort of mechanism I shall propose.
The argument I will develop is that both information and physical substrate
problems point to one solution; that consciousness is a property of a cell, not a group of
cells. No one special cell is implicated. It is proposed that all neurones are conscious,
to a degree; that the single subjective 'soul' is a confabulation.
Starting from William James
Late in the genesis of this viewpoint I received a timely prompt from Paul Marshall
to read Chapter VI of William James's Principles of Psychology (1890). Not only did I
find James discussing cellular
consciousness, or polyzoism, but considering it the only explanation which is not
He cannot accept it but his further comments are amusing: '... metaphysics, not psychology,
will be responsible for its career (having earlier defines metaphysics as '... nothing but an
unusually obstinate effort to think clearly.'). That the career may be a successful
one must be admitted ... a theory which Leibniz, Herbart and Lotze have taken under
their protection must have some sort of destiny.'
James abandons polyzoism for two reasons. Firstly, he assumes that it implies the
existence of a unique 'pontifical cell',which he rejects. As indicated above, my
view of polyzoism is democratic, not pontificial. The absence of a sense of
is implicit in James's exposition; 'Every brain cell has its own individual
no other cell knows anything about...' so one wonders why James did not
entertain the democratic version.
His second objection is more serious, arising from his analysis of the binding
problem in terms of nineteenth century atomistic physics. A composite structure such as a
brain is merely a construct of an outside observer, and 'non-existent as a
genuinely physical fact'.
The brain is a collection of little things, not one thing with the intrinsic identity that
would allow it to have a single subjectivity. And 'The cell is no more
a unit, materially considered,
than the total brain is a unit.' At the time, these arguments were irresistible.
However, physics has
changed since 1890 and I suggest James might have argued differently today
(see also Seager, 1995).
With James as foundation the exposition below develops three strands;
(i) retracing of the arguments addressed by James, but in a computer age
(ii) reclamation (hopefully) of the possibility of binding in the context of
modern physics, but only
within a cell, and (iii) exploration of the implications of cellular
consciousness to address further
obstacles that it may raise.
The information problem
In trying to identify a basis for consciousness, a definition of what is being looked for is
needed. Individual sensory elements or 'qualia' (Chalmers, 1995) seem beyond analysis,
but the binding
problem provides a handle. Thus, the key functional requirement of consciousness,
as I see it, is that
something has simultaneous (cotemporal) access to many elements (of information)
in defined inter-relationships (SAMEDI), i.e. access to a pattern. This requirement is not
sufficient to define consciousness
but perhaps covers sentience. Consciousness I will call sentience in which the accessible
pattern includes a useful map of some other 'outer' environment, normally the outside of a
human being, with a sense of time and, in its fullest form, adult consciousness, a
sense of self (see Bolender, 2001; Frith and Frith, 1999)).
The information problem is how to find a neurophysiological unit in the brain that could have
access to many elements of information as a pattern; perhaps 1000 elements
in a single experience. Some would say much more information is needed but I am assuming
coming in is not encoding every 'pixel' of the experience, but is built in an economical,
modular way (Searle, 2000)
The answer seems simple. A single neurone has SAMEDI for signals arriving from elsewhere
in the brain at its synapses. This is not meaningfully true
of a net of cells, each of which receives a separate set of signals. Although
it might be argued that the net 'as a whole' has access to the information as a pattern
this is not the case, as James saw clearly. Simultaneity of inputs to a logic gate such
as a cell, or semiconducting unit in a computer, is essential to the processing function of
the gate (the signals need to be in operation at the same time) but the timing of events at
other gates is irrelevant. Aggregate SAMEDI for several gates has no functional significance.
In an artificial 'neural net' in a computer that can 'recognise patterns'
the pattern does not exist as a pattern in the net. There is no representation of
the pattern in the sense of re-presentation. Nothing has SAMEDI for more than 0 or 1 and
0 or 1. Yet something in our brains does appear to have SAMEDI; we experience patterns
and these patterns seem to be relevant to the way information is processed.
There is no mechanism for access to information held in several
cells other than through
signals converging on a single cell. There is no more reason why information should be shared
between two cells a hundred microns apart in a single brain than between two cells in
two brains a metre
apart. The existence of a connection that might transfer information is irrelevant.
Such transfer of
information would change the pattern, if it indeed existed. Functionally, neurones
are as separate as people, capable of exchanging
information but not pooling it.
The idea that patterns are accessible as patterns in computers may have become accepted
because computers can imitate us. However, as Koch and Segev (2000) point out, there may be
a false premise here. It may be assumed that, because intercellular signals in the
brain are discrete pulses, as in a computer, information processing in the brain
involves only a mathematics similar to that of a computer. This is unlikely
(Koch and Segev, 2000). Integration of signals inside cells is complex and can
mimic multiplication. It may involve patterns. Thus although it might be argued
that binding in a cell poses the same problem as in a net of cells, it does not have to.
What we know of the brain indicates that binding could not occur between cells linked
by discrete signals but might occur in a cell. A sophisticated substrate might
be needed in the cellular 'black box' but if patterns are involved at all, this
would need to be the place. Put another way, postulating a new, unobserved
mode of integration between neurones begs the question why we need axons.
A non-bitwise mode of integration within cells is probably already supported
by experimental evidence.
In passing, I would make a comment made by many; that synchronised firing
(Crick, 1994) of neurones
cannot in itself create binding. Synchronisation of the traffic signals in
ten cities does not mean that anyone observes it.
Reading James I suspect that before computers the arguments must have
seemed much more obvious. Consciousness means binding, which means integration, which
happens in each cell separately.
The physical substrate problem: as seen by William James
It could be argued that binding occurs outside known physics, perhaps in
another set of dimensions. However, neuroscience continues to extend evidence
that experience depends on physical neural events at specific sites (Rees et al., 2002).
Biology is full of peculiar things getting an ordinary physical explanation.
It has also been suggested, in the functionalist view, that physical substrate
is unimportant, that what matters is the flow chart (Chalmers, 1995). However,
as Seager (1995) has pointed out, a brain has many different functions at different
structural levels and it is not clear why one or other should be endowed with
consciousness. Moreover, my argument is that the functions usually discussed
will not fit. Ironically, my final conclusion is that I agree with Chalmers and,
remarkably, with some of Dennett (1996) in that consciousness is a basic correlate
of function, but a function that only certain fundamental physical substrates can
subserve. To know the true function is to know the substrate.
The physical substrate problem is really the same problem as the information
problem, but in sharp focus. As James (1890) points out, a cell appears to be
just as much a collection of things as a brain. Access to many elements by a cell
is no good if no one 'atom' of the cell has that access, and specifically
simultaneous, or cotemporal, access.
I should point out here that pattern based information processing can be
explained in the conventional physics of 1890. For a cell to respond to a
pattern, no one part of the cell need be seen as having simultaneous
access to the pattern. If incoming signals create electrical waves which
interact in a way dependent on their pattern of phase relations, which in crude terms
we know they do, cell output can be pattern-dependent. However, in a classical
analysis no part of the cell has access to the pattern in the sense of
simultaneous availability of all the incoming signals in defined interrelationships.
For experiential binding, however, SAMEDI appears to be an absolute requirement.
Availability of either single bits of information in rapid succession or the single
value outcome of an interaction between waves is no good. We cannot escape by
saying our impression of simultaneous access to colour and shape
is an illusion. The mechanism needed to create the illusion is just as difficult to find,
even if it requires fewer elements than we tend to think we observe.
The importance of simultaneous access to information may be unfamiliar but it
has a long pedigree. It is implicit in Leibniz's view of the universe
(Woolhouse and Franks, 1998).
In classical atomistic physics 'access to information' can only really mean
exposure to forces. Gravitation is irrelevant in the brain, so the forces will
be mechanical or electrical. At the classical atomic level these are the same
thing, so that an atom can barely have access to more than one bit of information
at a time. A composite structure, such as a bit of brain, with different parts
exposed to each of 1000 different forces will not support subjective binding
because no one atom has simultaneous access to all these forces as a pattern.
For subjective binding we need at least one indivisible part of the brain to
have simultaneous access to the 1000 element pattern of forces, which classical
physics does not allow. Hence James's analysis that this is 'a total brain
activity which is non-existent as a genuinely physical fact.' There are two
facets of meaning to this statement. One is that atomistic physics does not
allow forces to act as complex patterns. The second is that composite structures
do not have the intrinsic identity that might allow them an individual subjectivity.
Fortunately, classical atomism would no longer be the place to look for
something as fundamental as subjectivity. Classical physics is now merely a
guide to what happens when things act as aggregates. As discussed below, modern
physics restores the possibility of subjective binding, because indivisibles have
access to many elements of information at once (Feynman, 1985; Bohm and Hiley,
1995; Seager, 1995). However, development of a coherent description of an observer
in modern physics has been slow and painful and might yet benefit from a little
help from Leibniz.
The physical substrate problem in the modern physics context
Many suggestions have been made about how quantum theory might explain
consciousness (Hameroff, 1994; Penrose, 1994; Seager, 1995; Ho, 1996;
Jibu et al., 1997; Globus, 1998; Esfield, 1999; Vitiello, 2001; McFadden, 2002)
although not always in the context of binding. While reasons for involving
quantum theory are often cogent, esoteric aspects are often invoked, such as
indeterminacy, wave function collapse and Bose-Einstein condensation. Some of these
are not even recognised in all versions of quantum theory (Bohm and Hiley, 1995).
Much of the resistance to these explanation relates to the implication of events
which tend only to occur under very limited conditions (Grush and Churchland 1995).
More general aspects of modern physics would be more attractive as a basis for a
Like many biologists interested in subjectivity I must declare my modern physics to
be largely self-taught, with advice from physicist colleagues. I have to take my
courage in my hands and build a set of ideas that I believe both theoretically
acceptable and accessible. An immediate problem is that conventional quantum
theory is reticent on what might have 'intrinsic existence' of the sort that
Leibniz, Descartes and James saw as important. Bohm and Hiley (1995), and Vitiello (2001)
I have found the most help in this area, although I see that no perfect ontological
view has yet been reached. For those who prefer a strict 'Copenhagen'
approach to quantum theory I would simply say that a theory that needs an observer
but cannot describe it or allow it to exist is no use to students of the mind.
Rather than seeing modern physics as 'quantum' superseding 'classical'
my impression is that there have been a series of conceptual shifts over
about 200 years, some of which may be rediscoveries, which I understand
roughly as follows:
1. That waves, (oscillating fields) and matter are inextricably linked (Maxwell).
2. That waves need not be just patterns of movement of things, but may in themselves be
things, or groups of things called quanta (Einstein's photons).
3. That all elemental things are waves (electron diffraction etc.; quantum theory)
4. That all true waves are things or groups of things inasmuch as anything
can be called a thing (modern field theory).
Put simply, the universe is populated by waves not billiard balls. These waves come
with associated positions in space but these positions are more like the cursor on a
line you draw with a computer graphics package than a site of a 'lump'. Moreover, in
an ontological analysis the wave and position must play quite different roles, an
issue beyond the scope of this paper. A wave is a perturbation with amplitude and
phase. It is not necessarily an 'up and down' oscillation. It may be more like a
spinning or corkscrewing and not necessarily in 'real' space. It is also indivisible; you
cannot have half a wave. (Try skipping over half a skipping rope.) If the indivisibles
(for Leibniz, monads) forming the basis of both observables and observers are waveforms,
then James's arguments need revising. The chime of a bell is an indivisible just as much
as an electron. James's argument '[when] H2 and O combine... the 'water' is just the
old atoms in the new position H-O-H' is wrong. The waveforms occupied by electrons
in a water molecule are new indivisibles.
Indivisibles that can be both observables and observers can reasonably be
said to exist in the sense required by Descartes. In Bohm and Hiley's (1995)
terms these are be-ables. This makes it reasonable to say that a bell exists
just as much as an electron, and that what defines this existence is a wave,
field or quantised mode of perturbation, rather than old-fashioned signs like
hardness, weight or opacity. The reader might question whether a chime is made
of quanta, as is a light wave. The answer from quantum field theory appears to
be yes; the quanta are phonons. There is a technical issue about whether the
field or the individual quanta are the be-ables. It seems it is the whole field,
which helps to move away from individual quanta which are unlikely to be of any
This discussion leads to the second reason for placing consciousness in a
cell rather than a brain. For something to be associated with a quantised
field or wave mode, that might give it the intrinsic identity a subject would
seem to require, it needs structural homogeneity and clear boundaries. A bell
supports such a field but a spoonful of porridge does not. The brain is forever
porridge. It is structurally highly heterogeneous and has no well-defined
boundaries. No perturbations with amplitude and phase can be expected to
occupy totally and exclusively the brain, or any component neural network.
Electrical waves in cells are exchanged for diffusional movements of chemicals
and back again it is all too divisible. On the other hand there is a chance
that a wave might occupy totally and exclusively a neuronal membrane. It may
be dangerous to jump to that conclusion and I shall explore it in more detail
later, but it may be the only chance we have.
Access to information by indivisibles
Having implied that a neuronal membrane might behave as indivisible, or monadic,
I need to return to the issue of SAMEDI. As indicated by Feynman (1985), the basic
difference between modern and classical physics lies in Young's double slit
experiment. A single photon passing through two slits in a screen shows
self-interference, indicating that it behaves as if it has simultaneous
access to information about both slits. It is not that one part of a wave
has access to one place and another part to another. However much a wave is
pared down in intensity, even to a single quantum, it maintains its complete,
indivisible, spatially distributed relationship to its environment. A photon
passing through a 'micro-colander' with 1000 holes has simultaneous access to
1000 elements of information as a pattern: it fulfils the functional requirement
of sentience. Moreover, this access to information informs the progress of the
photon. It is the 'active information' that determines the behaviour of waves
for Bohm and Hiley (1995). Put another way, if we are made up of waves we have
no justification in thinking that our sentience is any different from the access
to 'active information' of a wave.
We now seem to have a framework for indivisibles that can be both observables
and observers which have this peculiar binding property that we find in
consciousness. Both aspects of James's concern about 'genuinely physical
facts' are addressed. Note that the rules of access to information by
indivisibles are not those which govern access to information about indivisibles,
i.e. Heisenberg's Uncertainty Principle.
Which indivisible perturbations might carry
A number of suggestions have been made for perturbations that might
mediate consciousness. Several people have suggested that the brain's
electromagnetic field might help to explain binding, including Crick (1994),
McFadden (2002) and Pockett (2002). However, there are several problems with
'electromagnetic thought' some of which Pockett herself has well described
(Pockett, 2002). A brain's electromagnetic field is not obviously separable
from that of the spinal cord, nerves, skin, or even clothes. There is no
evidence that the electromagnetic field generated by neuronal activity is
involved in processing information in a way that could influence behaviour.
The radiofrequency photons that form the field would be scattered and
absorbed at random or pass rapidly out of the body. Much of the information
they have access to would be about irrelevant brain 'plumbing' like blood
vessels. We need perturbations that stay in a demarcated, ordered but potentially
complex domain and are tuned to data mapping the outside world.
Hameroff (1994) has suggested that microtubules might be a substrate
for consciousness. However, it is in the cell membrane that electrical
waves generated at synapses, tuned to information about the outer world,
are integrated. A translation of information to microtubules might seem
excessive. Membranes can support more complex wave patterns than filaments,
being essentially two, rather than one, dimensional. Anchorage to the
cytoskeleton might, nevertheless, modulate membrane waves either mechanically
or through ionic fluxes; the two structures might function as a unit, like
'cello string and sound box.
In a sense we know that the integration of information in neurones
involves the interaction of electrical waves spreading out from synapses,
according to the rules described by Hodgkin and Huxley. We know that those
waves operate within the demarcated, ordered semi-crystalline domain of the
cell membrane. The simplest solution would be if these are the waves
associated with sentience. But do they have the right properties?
The hypothesis seems to make two requirements of a wave that might endow the
neuronal membrane as a whole with sentience linked to behaviour. Firstly, a
wave with access to information about the state at all synapses would need its
wavefront (or domain of non-trivial amplitude) to occupy the whole neuronal
dendritic tree. This would seem to require a reverberating wave with time to
make several passes like the resonation of the bell. In Vitiello's (2001)
terms it would be a long range correlation. Secondly, to be describable as a
quantised field it probably needs to be energy conserving, at least to a first
It is not clear that a purely electrical wave with these features exists.
The basic Hodgkin-Huxley wave is a simple damped, dissipative biphasic packet.
Fröhlich (1968) suggested an electromechanically coupled wave in which electrical
and elastic potential were exchanged. He suggested that this wave might be a
Bose-Einstein condensate, but this seems unlikely and is as far as I can see
unnecessary. There is no doubt, however, that electromechanical coupling can
occur in neuronal membranes. As shown by Iwasa et al. (1980), an action potential
is associated with a mechanical wave. Petrov (1999) has shown that as polar
planar liquid crystals, cell membranes generate biologically relevant voltages
when flexed and vice versa. This is a form of piezoelectricity, called
flexoelectricity, involving coupling of phonons to an electrical field.
At least in isolated sheets of membrane modes of electromechanical perturbation
can be established. Of note, there is increasing interest in electromechanical
coupling as fundamental to the way cells sense their environment and respond
through opening and closing ion channels (Zhang et al., 2001; Kumanovics et
al., 2002). It has been suggested that this might be particularly relevant
to sites of membrane curvature such as neuronal dendritic spines (Zhang et al., 2001).
Many attempts to relate consciousness to modern physics have sought to
identify new mechanisms for information processing in the brain ((Hameroff,
1994; Penrose, 1994; Jibu et al., 1997; Globus, 1998; Vitiello, 2001),
giving sentience a place in the causal chain. I was initially drawn by
this line of thought despite being advised by people such as Andrew Huxley
and Horace Barlow that new mechanisms look dangerously redundant. I
then realised that although quantised fields may help to explain bound experience,
that this in no way implies that a 'field of sentience' should contribute to output
in an active way. In fact there are several arguments against, which I can only
cover briefly here.
Assuming that the field of sentience is some sort of long range electromechanical
(perhaps piezoelectric) correlation, then an active effect on information
processing should be through local modulation of the parameters of
interacting Hodgkin-Huxley waves; either membrane dimensions or capacitance
or conductance terms. However, there is good evidence that these are constant.
Moreover, active involvement in the electrophysiological process would require
work and that would be at odds with an energy conserving field. Although
primitive organisms and specialised cells like cochlear hair cells translate
electrical effects into movement, neurones appear to be adapted to being an
immobile substratum for electrical interactions. Neural spine design may actually
minimise membrane movement.
The resolution of the problem seems to be that a field of sentience can just as
much be bound into the causal chain by being inseparably associated with constant
parameters for each cell. In this model the field of sentience can be compared to a
chess board which is a passive but essential component of the causality of the game.
The causal power of a chessboard may seem limited but the causal power of ten billion
chessboards each with ten thousand squares, connected by trillions of pathways subject
to feedback-related plasticity would not be.
It remains uncertain as to precisely what long range correlations exist in
the cell membrane as a whole, or at least throughout the dendritic tree.
Nevertheless, the key point remains that whereas resonant waves in a
large chunk of brain are implausible, they are reasonably plausible in a cell membrane.
The above account may appear to leave something missing. It has been argued
that experience itself must affect output if we are to talk about the nature of
experience and its role. But I would argue that we only ever talk about the
content of experience, which is carried by conventional interacting Hodgkin-Huxley
waveforms, as it appears to a sentient entity similar to those from which it
arose. My feeling is that the above does provide an adequate account of
causality and that any apparent inadequacy arises from the dynamics being
counterintuitive. Specifically, I would argue that if a paradox remains it
cannot be resolved by suggesting another active mechanism in addition to the
electrophysiology we already have evidence for. The proposal is, therefore,
that there is a solution to the binding problem which requires nothing esoteric
and nothing for which we do not have some experimental support, as long as it
operates in each cell separately. If a cell can support modes of
electrical/mechanical oscillation in its membrane, as a liquid crystal
should, we have no reason not to expect it to have a sentience (SAMEDI)
which mirrors the cell¹s input. If the input maps the outer environment,
the cell is conscious, and if the input maps the self, it has adult
consciousness. Sentience remains awesome, but not at odds with physics.
Encoding the world into a conscious map
Could a neurone support enough information to explain the richness of
visual experience? During the process of peer review I discovered that
Steven Sevush has come to much the same conclusion as myself from a
different standpoint, specifically addressing the neuroanatomical
feasibility of cellular consciousness (Sevush, 2004). Each cell has
thousands of synapses which can receive tens of messages a second.
We think we are aware of hundreds of things at a time, but it may be
much fewer (Noë, 2002). I suspect that what we think of as the full
detail of an image is not downloaded into a cell, but that modules of
experience embedded in the fine structure of the neurone are 'called up'
by economical incoming codes. Moreover, our experience does not seem to be
formed from 'pixels', but in a language of preformed elements (Searle, 2002).
Binding of qualia based on electrical wave patterns might be more like
transforming topologies than digital addition. We assume a cell could not
support a whole picture because we are used to images built up with a
paint brush or a VDU but that is not how waves work.
A worrying feature of Bertrand Russell's point that all we are ever
aware of is the inside of our head, is that it is hard to see why some
part of the inside of a head should see in itself a landscape, an
interior, or any other view of the world. If consciousness is in one
cell the question becomes why a pattern of electrical phenomena in a
membrane should give rise to sensations like yellow and lemon-flavoured,
meaningfully interrelated. The initial answer would seem to be that we
have no reason to think we can expect to predict how a cell membrane should
experience itself or that it should not be what we do experience. At
least it is a unitary physical substrate rather than the abstract
'functional' substrate of apparently indistinguishable signals passing
along separate paths.
A number of people have looked for relationships or equivalences
between subjective space and time and 'outside' space and time,
raising points worthy of much further debate (Marshall, 2001;
Bolender, 2001; Romijn, 2002). However, to include emotion, colour
and taste, we have to assume considerable non-equivalence and it
may be that outside space is encoded in both space and time and
outside time similarly. Specifically, I would suspect that dimensions
may be encoded in differentials in time (rates of change) since that
is what waves are about. This might bear on the concept of the
'specious present', in which physical events dissociated in time
are perceived as co-temporal but offset from an objective present.
There may be no reason to think that 'a moment¹s thought' lasts 'a moment'.
The issues of time and differentials in time suggest a reason for
the association of synchronised electrical signals with consciousness
(Crick, 1994). While implication of synchrony in an intercellular
model of binding seems untenable, synchrony should have a vital role
in an intracellular binding based on patterns of wave interaction.
It may be possible to deduce the language for encoding the outside
world into an internal map by considering constraints such as the
need to integrate input from different senses in congruent dimensions.
However, unlike normal languages, with meanings shared between
individuals, a wave-based language of sentience would only be used
by a cell to experience itself. Communication with other cells would
be via discrete signals, not wave patterns. If two adjacent cells
used a pattern in one case to be yellow and the other to be lemon-flavoured,
it should not matter. All that is required is that the cell experiences
a sensory input of yellow in the same code as a signal indicating the
memory of yellow. Much more could be said on this subject but it may be
that the rules governing the language of experience are more flexible,
and usage less constant, than might be expected.
What is known about intracellular signal processing?
As reviewed by Koch and Segev (2001), integration of incoming signals in
neurones has often been considered as a summative electrical process.
However, Koch and colleagues have shown that this is too simple and
that integration fits best a complex partly digital, partly analogue
model including something equivalent to multiplication. This makes
true pattern-based processing a serious possibility. Koch also points
out the diversity of dendritic morphology in different types of
neurone, suggesting that integration may involve combinations of
processes with different emphasis on one or other process in different
cell types. Apical, oblique and basal dendrites may have different
roles in a single cell.
Summative integration is of no use as a basis for conscious experience.
A thousand signals integrating in a summative fashion can generate two
meanings; enough or not enough. With pattern-based binding the number
of meanings could be 2 to the 1000th or more (about 1 followed by 300 zeros),
enough for a separate meaning for every millisecond of life of every cell
in every brain that ever lived. It would be a mistake, however, to assume
that pattern-based integration is always advantageous. If it is possible
at all, setting up waves with useful effects may require both very
sophisticated cellular microstructure and very sophisticated regulation
of information input. A digital computer can solve almost any problem
with enough speed and memory. An individual pattern-based unit may only
be able to solve one problem, or very few. Any one cell, may experience
a panorama but only occasionally contribute to behaviour by identifying
a local pattern match to which it is tuned.
A lot more information is needed about intracellular computation and
its potential link to sentience. However, the hypothesis being explored
makes a testable prediction; that at least in some neurones, complex
patterns are involved.
A copy of consciousness in each cell: why not?
The picture I have painted is of two components to brain processing,
acting in series rather than parallel. The intercellular part of
processing is synaptic, non-bound and like a computer. The intracellular
part has a synaptic input, is at least partly pattern-based, is
available to a sentient field with SAMEDI that is a be-able in Bohm and
Hiley's terms, and leads to an electrical output. From both informational
and physical substrate points of view this seems to be the only model that
allows binding. The main difficulty may be cultural. We think we have a
single sentience. I am proposing we are colonies of sentient cells, each
with a hermetic unshared consciousness. We believe as a debating house
believes, worship as a congregation. Is such a view consistent with experience?
Although the literature is dominated by the idea of a single centre of
consciousness, the alternative idea of more than one centre of consciousness
is not new. As indicated, William James considered a pontificial polyzoism
very seriously and implied that the idea had a long tradition. However, in
a democratic polyzoism there is no single 'me' cell; in at least some parts
of the brain there may be millions that have the experience of being me.
This has the advantage that it is consistent both with James's fundamental
requirements for binding and with the apparently distributed nature of
consciousness. It is also very compatible with the 'holographic' aspects
of consciousness described by Pribram (1991) in the sense that a version
of the 'experiential story' is distributed widely throughout the brain.
If one neurone benefits from sentient pattern-based processing why not all?
I suspect that 99% of what goes on in my brain is decided on somewhere other
than the site of any subjective viewpoint that I see it from. This 99% is
termed unconscious, but a lot of the clever things that brains do emerge
from this unconsciousness. It would be easier if, rather than being
unconscious, these events were in other cellular consciousnesses, or
at least sentiences. This would resolve a problem with Penrose's (1994)
masterly argument that conscious thought is non-computable; that the best
thoughts often seem to surface from somewhere else.
Although held in a cultural framework, the belief that we have a
single self probably has an inbuilt biological basis. As indicated
by Frith and Frith (1999) and by Gazzaniga (1998), there is evidence
that one or more regions in the left frontal region are responsible
for a story of self which makes sense of our relationship to the
world and other selves. In individuals with autism this story may
have different rules or may not be told at all. The story telling
may be almost unique to Homo sapiens and may be the source
of our success. It may be a useful myth.
How the story of self works is unclear. Certain cells in my left
prefrontal area may be those that think they are me. It might
also be that they regulate the flow of, perhaps synchronised,
impulses which determine the focus of attention for other cells.
The profuse branching of many axons would allow a pattern of signals
to be distributed widely, such that large numbers of cells could
receive a copy of the same story of self which they interpret as
their own. Democratic polyzoism does not alter the need to answer
questions about how intercellular pathways build up the story. It
just suggests that these questions may have a different relationship
experience in terms of site and copy number.
We are brought up to think that our brains are conscious as a
whole but we are also taught that the cell is the living unit
and that chemical processes are regulated individually in each
cell. The Darwinian reasons for retaining separate biological
machinery in each cell may apply equally well to consciousness.
The existence of consciousness in each neurone is very much in
keeping with what we know about recovery after brain damage.
Patchy loss of grey matter or tracts of white matter would leave
many cells to relay the contents of their consciousness to the
outside world, with defects in certain areas relating to the lack
of input from sister cells. A copy of consciousness in each cell
might be the safest way to protect against threats such as
birth trauma or measles encephalitis.
However wasteful it may seem, every cell has a copy of the
genetic blueprint of our bodies. Why does each cell not hold
a consciousness, or at least sentience, in its membrane? Each
cell's version would differ, more like the proteome than the genome.
Red blood cells have no genes and are unlikely to make use of
membrane waves. Skin and bone cells might have little use for
sentience, but in a wound they undertake repair with considerable
skill. They would not have access to the sort of mapping system
generated in the brain but nevertheless, integration of selective
information about the cell's environment in the cell membrane
might be used for regulating changes in cell shape and sites of
secretion of tissue fibres. Sentience for them and for phagocytes
might have no extended temporal reference. On the other hand some
such cells may show behaviour suggesting memory or learning
(Frost, 1996). Since each contains enough genetic information to
build a brain we should not exclude the possibility that they have
a 'programmed self'. Neurones have a much more stable cytoskeletal
structure and their form of consciousness may be incompatible with
locomotion. Nevertheless, looking for evidence of integration by
patterns and waves in single cells might be easier than in neurones.
The effects of anaesthetics on
single cells might be worth much more study.
Conversely, complex pattern-based integration might not be a
major feature of all neurones. Neurones in peripheral nerves
may be little more than linear electrical relays, less 'intelligent'
than phagocytes. Neurones in the brain would generally be expected
to use sophisticated integration and mapping, perhaps especially
to generate abstract concepts, language and introspection but some
cells may only deal with information from the retina or ear. The
thoughts that we exchange in conversation may go on in rather few
cells, but it is still possible that very many neurones are aware
of a similar breadth of information but in a 'dialect' suited to
their field of action. Perhaps the
various shapes of dendritic trees hold clues.
Although consciousness is often related to the cerebral cortex,
it is not absolutely clear that this is where a sense of self would
reside. The thalamus is also crucial to consciousness and is densely
supplied from overlying cortex. It is not inconceivable that this is
where the 'me' cells might be. Parts of the brain stem, notably the
peri-aqueductal grey matter, are crucially important to consciousness
in the sense of being awake and responsive (Panksepp, 2002).
Specialised cells in this area might be the ones to hold the
consciousness that people write articles about. However, many would
argue that these areas simply control wakefulness and sleep by sending
out signals which
regulate synchronous discharges elsewhere.
Why, if consciousness is in a single cell, do humans have such a
large brain? Brain size is frequently related to intelligence,
sophisticated behaviour, and everything we associate with the
'higher consciousness' of man. This, I suspect, is one of the
most misleading premises of consciousness studies, as shown by the
comparison of a bee and a cow. A bee has about a million times fewer
neurones than the cow. The bee can talk to its hive mates in quantitative
geometry and fashion hexagonal arrays. Cows seem to do little except eat
grass. Brain size has little to do with sophistication of behaviour or
social activities. An orang-utan may paddle a canoe and have a place in
a group hierarchy. A crow with no cortex and a nut-sized brain can use
a tool to get food from a jar and has a pecking order in much the same
way. Brain complexity may give more scope, but it should not be seen as
central to the consciousness issue. What may well be true of insects is
that they do not have room for the networks needed for self-consciousness.
Complex cellular consciousnesses may exist in greater isolation. The
neurones controlling chomping mouthparts may not recognise as 'me' the
leg being simultaneously
chomped by another animal (Penrose, 1994).
One might ask why one's experience belongs to 'this' cell, or
why we wake up every day as the same cell. These are valueless
questions, no more puzzling than why we are not turnips, or on
Mars. The cell(s) you are at this moment refers to a congruent
library of incoming memories. We would never be in a situation
of saying, why am I a different cell from the one I was yesterday,
or how come my body goes
on talking when I have died of a stroke?
A consciousness in each cell might be relevant to aberrations in
experience and mental illness. We talk of being in two minds, suggesting
that although conflict within a consciousness may not be possible, conflict
between conscious entities may be just below the surface. What is going on
in those people who smile on one side of their face? Do people claiming to
have more than one personality have segregated subgroups of self-narrating
cells? Are hallucinations and other features of schizophrenia due to failure
of regulation of the input of the self story into self-conscious cells? The
are hard to answer with a global self.
In these questions there is a considerable danger in confusing the content
of consciousness, input from other cells, and the way it is processed in a
single cell. If consciousness in each cell should alter our interpretation
of our experience I suspect it is in a subtle way which needs to be analysed
with care. Nevertheless, the implications of looking at ourselves as colonies
rather than individuals are not trivial. Even in terms of traditional
neuroscience it cannot be controversial to say that decisions are not
made by men and women but by cells. However, the idea that those cells
might be the only conscious actors in the play may highlight just how
relevant this is to real life. Politics and spin go on inside as much
as outside as the Prince of Denmark
and the Moor of Venice were well aware.
It must, however, be stressed that anarchy within a democratic polyzoism
is not to be expected. Conflicts may chiefly arise when the self story is
mismatched to the social environment. All the cells in the brain survive
together, so there will be no pressure to compete. As in a general election,
the retelling of the self story will be based on a consensus from the neural
polls. If free will is a meaningful concept, which I personally doubt, every
cell will make a very small contribution. Moreover, cells will have no
knowledge of what their own contribution is. The cell's output, the action
potential, probably simply wipes the membrane clean of incoming patterns.
All is designed for co-operation, as for the asexual workers in a beehive.
Put another way, democratic polyzoism is functionally no more than those
same co-operative interactions of individual cells the neurophysiologists
have already identified
functionally it is the way we know it is.
Perhaps the most disorientating implication is that there may be no
single subjective soul that controls our behaviour. We think of everything
we do as being controlled by one being, and in general we see this being as
something that communicates through language, including the writing of papers
on consciousness. But the question of which cells ultimately control our
conscious behaviour (Ramachandran and Hirstein, 1997; Frith and Frith,
1999; Crick and Koch, 2003) is likely to be too simple. Every action
involves thousands of cells. Some communicate through talking or writing
because they have verbal inputs. However, our perception of consciousness
in others need have nothing to do with words. We sense that animals are
conscious without them speaking. Eye contact tells us of consciousness,
leaving the verbal mind straggling behind. Different members of our colony
interact in different ways with animate and inanimate entities. Such
interactions may involve consciousnesses which may be full of emotion
but dissociated from speech. When we hear Casals we recognise across
time the power of cells that speak without words. When we look at Bonnard
we know that true intimacy is silent. Perhaps consciousness studies are
the fruit of nerd cells that need to go out and get a life rather than
just a second hand story from the real players!
If indeed every cell is independently conscious, the implications may be
far reaching. Nothing I have so far encountered seems to make the concept
incompatible with experience. The main problem seems to be our shared
preconception of the existence of a single sentient self. The idea is
potentially testable, since it predicts that intracellular information
processing is based on complex patterns, at least in some cells. It also
requires the existence of long range correlations in membranes, that might
be amenable to probing via sensitivity to general anaesthetics. Until such
time as it is tested experimentally it can only be judged on Ockham's rule
of parsimony. It is probably as parsimonious as any other suggestion. No
new physics and little, if any, new biology are required.
Bohm, D. and Hiley, B. (1995) The Unidivided Universe. (London, Routledge).
Bolender J. (2001) An argument for idealism. Journal of Consciousness Studies 8, 4, 37-61.
Chalmers, D. (1995) Facing up to the problems of consciousness. Journal of Consciousness Studies 2, 3, 200-219.
Crick, F. (1994) The Astonishing Hypothesis. (New York, Scribners).
Crick, F. and Koch, C. (2003). A framework for consciousness. Nature Neuroscience 6, 2, 119-126.
Esfield, M. (1999) Quantum holism and the philosophy of mind. Journal of Consciousness Studies 6, 1, 23-38.
Feynman, R. P. (1985) Q.E.D. (Princeton, Princeton University Press)
Frith, C. and Frith, U. (1999) Interacting minds a biological basis. Science 286, 1692-1695.
Fröhlich H. (1968) Long range phase correlations in biological systems. Int. J. Q. Chem. 2, 641-649.
Frost, H.M. (1996) Perspectives: a proposed general model of the 'mechanostat' (suggestions from a new skeletal-biologic paradigm). Anat. Rec. 244, 139-47.
Gazzaniga, M. (1998) The mind's past. (Berkeley, University of California Press)
Globus, G. (1998) Self, cognition, qualia, and world in quantum brain dynamics. Journal of Consciousness Studies 5, 1, 34-52.
Grush, R. and Churchland, P.S. (1995) Gaps in Penrose's Toiling. Journal of Consciousness Studies 2, 1, 10-29.
Hameroff, S. (1994) Quantum coherence in microtubules. Journal of Consciousness Studies 1, 1, 91-118.
Hardcastle, V.G. (1994) Psychology's binding problem and possible neurobiological solutions. Journal of Consciousness Studies 1,1, 66-90.
Ho, M-W. (1996) The biology of free will. Journal of Consciousness Studies 3, 3, 231-44.
Iwasa, K., Tasaki, I. and Gibbons, R.C.. (1980) Swelling of nerve fibres associated with action potentials. Science 210, 338-9.
James, W. (1890) The Principles of Psychology. Chapter VI The mind-stuff theory. (Cambridge MA, Harvard University Press).
Jibu, M. and Yasue, K. (1995) Quantum brain dynamics and consciousness. (Amsterdam and Philadelphia, John Benjamins).
Koch, C and Segev, I. (2000) The role of single neurons in information processing. Nature Neuroscience suppl 3, 1171-1177.
Kumánovics, A., Levin, G. and Blount, P. (2002) Family ties of gated pores; evolution of the sensor module. FASEB Journal 16, 1623-29.
Marshall, P. (2001) Transforming the world into experience. Journal of Consciousness Studies 8, 1, 59-76.
McFadden, J. (2002) Synchronous firing and its influence on the brain's electromagnetic field. Journal of Consciousness Studies 9, 4, 23-50.
Noë, A. (2002) Is the world a grand illusion? Journal of Consciousness Studies 9, 5-6, 1-13.
Panksepp, J. (2002) The primordial self. In Consciousness, Carter, R (Ed.) pp 186-188. (London, Weidenfield and Nicholson).
Penrose, R. (1994) Shadows of the Mind. (Oxford University Press).
Petrov A. (1999) The Lyotropic State of Matter. Gordon and Breach, Amsterdam.
Pockett, S. (2002) Difficulties with the electromagnetic field theory of consciousness. Journal of Consciousness Studies 9, 4, 51-56.
Pribram K.H.. (1991) Brain and Perception. Lawrence Erlbaum, New Jersey.
Ramachandran, V.S. and Hirstein, W. (1997) Three laws of qualia. Journal of Consciousness Studies 4, 5-6, 429-457.
Rees, G., Kreiman, G. and Koch, C. (2002) Neural correlates of consciousness in humans. Nature Reviews: Neuroscience 3, 261-270.
Revonsuo, A. and Tarkko, K. (2002) Binding in dreams. Journal of Consciousness Studies 9, 7, 3-24.
Seager, W. (1995) Consciousness, Information adnd Panpsychism. Journal of Consciousness Studies 2, 3, 272-288.
Searle, J. (2000) Consciousness. Annu Rev Neurosci 23, 557-78.
Sevush, S. (2004) Single-neuron theory of consciousness. Cogprints.org/3891/
Vitiello, G. (2001) My double unveiled. (Amsterdam, John Benjamins)
Woolhouse, R.S. and Franks, R. (1998) G.W. Leibniz, philosophical texts. Oxford, Oxford University Press.
Zhang, P-C., Keleshian, A.M. and Sachs, F. (2001) Voltage-induced membrane movement. Nature 413; 428-31.