Single Cell Consciousness
This is a conjecture about the nature of self which has evolved on this page since October 2002.
Published and in progress papers can be found at 'Is consciousness
only a property of individual cells? Journal of Consciousness Studies 2005,
4-5, 60-76, 'Are our spaces made of words?' Journal of Consciousness
Studies 2008, 1, 63-83, 'Back here on zombie earth' Submitted and
'The Location of Representations' In progress.
Further informal ideas can be found at Short Thoughts.
A quick comment about the God Delusion is also here.
For an extended account of the ideas in book form, designed for a general audience
see How Many People Are There In My Head And In Hers?
Perhaps the most baffling unanswered question in science is how the physical working of the brain
gives rise to conscious awareness. There are several reasons for this question being difficult,
but the most important may be that we are looking for the wrong sort of answer. Almost everyone
assumes that we are trying to explain one copy of awareness in each person's brain, one observer,
one subject; one consciousness. However, as William James pointed out in 1890, having one copy of
awareness in a brain makes very little sense, whether in terms of logic, physics or neurology. It
would make much more sense if there were lots of copies and lots of subjects, even if it seems odd.
There is also a basic biological reason for there being many subjects in a brain; a
brain is not a single life unit but a colony of cellular life units which are not joined together
by any mysterious 'life force'.
The hypothesis of Single Cell Consciousness (also known as the Single Neuron Theory of Consciousness)
arose from the simple strategy of trying to find an explanation for awareness that fits with what we
know about the physics of the brain. There appears to be only one option that works; that each brain
cell is aware separately. Although this may seem to conflict with our experience it almost certainly
does not. This is a brief review of the approach, with more detail elsewhere.
The philosopher Daniel Dennett might be said to have come to a similar conclusion, in proposing
that our awareness comes in the form of 'multiple drafts' throughout the brain. However, Dennett
provides no specific physical basis for his suggestion and so does not really address the key
problems. Single Cell Consciousness deals with these problems head on, by specifying that each
copy of awareness belongs to an individual cell and is as complete as we experience, rather than
being a partial 'draft'. There can be no 'combined' or 'global' awareness over and above the
awareness of each cell. Not only would this require some strange metaphysical 'glue' but it
would be in direct contradiction to what we know about how the brain works.
Many people's reaction to this suggestion is that it cannot possibly be true, or that
they cannot even see what it could mean. However, I would
respectfully suggest that this simply indicates how deeply rooted false assumptions can
be. The key point is that, whatever difficulties there might be with this idea, they
might be soluble, whereas the difficulties with the idea of a single awareness in a
brain are not only worse, they are insurmountable.
Taking the idea of an observer seriously
Physics, and particularly modern physics, relates everything to an observer. An observer is
something that receives information about other parts of the universe from a particular frame
of reference, which includes position, time and movement. An observer is something with a
single relationship to other parts of the universe. It cannot be a collection of things, each
with a different relationship to the universe and, therefore, receiving different information
about the universe. Physicists assume that a human being can provide a single thing with a
single relationship to the universe, but it quite obviously cannot, since a human being is
a collection of things with different relationships to the universe. Even the brain is such
a collection, and quite specifically a collection of nerve cells, each receiving a separate
input of information from a different frame of reference.
It might be argued that the brain could be considered as a whole, with a single set of inputs
from all the nerves coming from eyes, ears, fingers and elsewhere. But that is not what a brain is.
The brain is mostly made up of the connections that allow these inputs to be brought in, tidied up,
collated and compared with past experience before they are received by an observer. We cannot
say that the information coming in to the right side of the brain and the information reaching
the left side of the brain are reaching a single observer, because there is nothing that gets
both inputs. Not only can nothing act as observer for both sets of inputs, nothing can respond
to the combination of the two inputs because they are arriving at different places, one of which
has no information about what is arriving at the other.
The idea of a brain being one observer is simply logically incoherent. It is neurologically
meaningless. It is incompatible with physics. The fact that so many people find this hard to
accept, even professors of neuroscience and philosophy, probably indicates that we are
genetically programmed to believe each of us is a single observer. This belief may be so
inbuilt that denying it may simply not be possible for some people.
What neurology tells us
What neuroscience has established is that each brain cell functions as a separate receiving unit.
There are a variety of routes for passing information from cell to cell, including direct channels
between cell interiors in some cases. However, there is no evidence of sharing of complex patterns
of incoming information, and it is complex patterns of incoming information that we need for the
sort of observing that we seem to experience. If cell A has a pattern of 10,000 inputs through
its synapses in 10 milliseconds, that pattern is not available to cell B, and vice versa, even
if cell A and cell B have links between their cell bodies. Cells could be observers, but brains
If there are many observers in a brain it might seem that there should be conflicting experiences,
and behaviour should be reduced to chaos. However, this is not what neurology predicts. The
information coming in to every cell would be consistent, since it arises from the same sensory
input. Inasmuch as two brain cells dealt with the same sort of information they would get copies
of the same input. There is no doubt that information coming in from the senses is sent out in
many copies to many cells. A cell in the occipital cortex, which fires when inputs from the retina
indicate that an edge of an object has moved, will send that information to perhaps ten thousand
cells. The idea that there might be thousands of cells all receiving the same information is
entirely consistent with what we know about brains. Again, the idea of a single observer with
a single copy of an input is absurd, because everything in the brain is sent around in lots of
What seems to have happened in the development of a received dogma about the link between
awareness and messages between brain cells is that these thousands of copies of a piece of
information are seen as somehow 'in bulk' generating awareness. But this does not make sense
because in order for the information to mean anything it has to arrive at a receiving unit,
our observer, along with whatever other information it is to be experienced with (brown and cow,
red and lorry) so that it can be made use of. Presumably only one copy of any piece of
information will arrive at any receiving unit (a cell). Other copies would have no further
meaning to the observer in hand. All they can do is provide a meaning to other observers.
A new prediction
One of the advantages of the Single Cell Consciousness idea is that it poses a problem that
ought to have a solution that can be confirmed by experiment.
As William James pointed out, the arguments that make the idea of a brain as a single
observer absurd also cast doubt on the possibility of a cell being an observer. A cell is
a single receiving unit in neuroanatomical terms, but in fundamental physical terms it
may not be. It could be argued that a cell is a branching tree of separate receiving units,
each of which receives the information coming in to a tiny piece of cell membrane but
nothing else. You might even say that each atom of the cell receives its own information
and there is no possibility of an observer being more than one thing; one atom. This is a
serious problem if you stick with 1890 physics. However, modern physics may offer a way out.
In modern physics the elements of the universe are not tiny lumps but rather oscillations with
strange properties attached to them such as spin, mass, and charge. Although some of these
oscillations are familiar subatomic particles, some cover much larger domains and are known
as long-range correlations. Thus a piezoelectric crystal is 'inhabited' by quantised
long-range correlations in which transient photons are coupled to 'phonons'. A long-range
correlation behaves as a whole with no parts, so any information received at any point in
a domain defined by such a long-range correlation can be seen as being received by a single 'thing'.
Almost by definition, cell membranes, as liquid crystals, should be inhabited by
long-range correlations. In fact piezoelectric oscillations are recognised in specialised nerve
cells in the inner ear known as outer hair cells. To be of any relevance to awareness in cells
within the brain such oscillations would probably have to be higher frequency and lower
amplitude, but it would not be unreasonable to predict that such oscillations might exist.
Thus the suggestion is made that the observers in our heads are piezoelectric oscillations
and that these should be discoverable.
What should we be expecting?
The idea of an observer being a piezoelectric oscillation may seem very peculiar,
but it is worth considering what logic would suggest that an observer ought to be.
A number of people have suggested that the observer in our heads is some quite extensive
collection of brain cells, given some sort of unified status by interactions at the quantum
mechanical level. Many other people reject the idea that quantum mechanics is relevant.
However, I would agree that since observing seems to be such a fundamental physical
process, an observer really has to have a description in the fundamental terms that
are provided by quantum theory in modern physics. There are, nonetheless, three serious
problems with making a collection of cells the observer.
Firstly, we have no reason to think that the combined inputs to many cells have any function
role in the brain, nor that they should have any useful computational role. To make a group
of cells an observer, in the sense of a receiving unit, is essentially to say that our
experimentally tested view of how brains work is wrong. There needs to be a very good reason
to do that. Thus, to ascribe a quantum level unity to structures in the brain that appear to
have no classical biological functional unity does not seem helpful.
The second problem is that a group of cells is made up of many fundamental units and
finding a quantum mechanical explanation for these having a common access to a pool of
information requires proposing things that are at best highly speculative and at worst
totally unverifiable. Concepts such as 'spontaneous wave function collapse' and 'entanglement'
have been invoked. The problem is that no current theory gives any idea why these events should
make signals in one part of the brain co-available to a particular group of cells with other
signals not being available. No boundaries are defined.
The third problem is that a unification of many cells at the quantum mechanical level
would seem to have to include all sorts of particles that have nothing to do with the
information our observer ought to have access to. Entanglement involving mitochondria or
nuclei would be inappropriate. The information our observers are aware of is held as
electrical potentials across cell membranes, with, as far as we know, no further transference
to other cellular structures. Moreover, entanglement would link quantum mechanical properties
at the atomic or molecular level and the relevant information is held at a different level
involving areas of cell membrane about a micron across (made up of many millions of molecules).
The point emerges that whatever fundamental physical feature 'unifies' our observer it needs
to match up with a relevant biological structure. The feature needs to demarcate a domain and
needs to operate on the right scale. A long-range correlation in a cell membrane would seem to
do this very well but more speculative concepts like entanglement and spontaneous wave function
collapse would not. Moreover, there can be no doubt that the phonon-based mode of a
long-range piezoelectric correlation has access to the information held in the pattern of
local electrical potentials across the cell membrane. This access is the basis of the 'coupling'
of electrical and mechanical fields that makes piezoelectricity what it is. In contrast, it is
very unclear in what sense a collection of particles unified by wave function collapse or
entanglement would have this access. It is not something that has any recognised place in
conventional physics theory; it seems to be just a metaphysical speculation.
A long-range piezoelectric correlation might seem to be a rather insubstantial basis for an
observer. It has no mass. However, it should be noted that such a long-range correlation is
in a sense inseparable from the cell membrane that it inhabits. To say the correlation is
the observer is hardly different from saying that the cell membrane is the observer. Moreover,
the piezoelectric correlation may involve acoustic parameters determined by the cell as a whole,
so that it may be reasonable to say that the whole cell makes a necessary contribution to the
observing unit, and thus may legitimately be called the observing unit.
A function for the observer
Whatever the observing units in our heads are, it seems reasonable to think that their
observing is part of a process that leads to a response that is based on what is being
observed. For an observer made up of a net of cells this does not make much sense. Each
cell responds separately and only to the pattern of signals coming in to that cell. There
is no sense in which the output from one cell is a response to the input to lots of cells.
If the observing unit is a cell then things make sense because the output of a cell is
dependent on the pattern of inputs to the cell.
Although it is difficult to be sure exactly what long-range correlation might allow a
cell to act as a single receiving unit, a phonon-based of oscillation would provide a convenient
means to link input to output. The mode would take up energy from the local electrical
potentials that are the incoming signals in the dendrites of a neuron. According to the
entire pattern of incoming potentials the mode would then return energy to the electrical
mode and thereby modulate the output of the cell in terms of firing signals down its axon.
The idea that 'decisions' are made on the basis of patterns of information in lots of
places at once in a brain is entirely in line with neurobiology and yet there appears
to be an assumption made by many people, including neuroscientists, that the brain makes
one 'conscious decision' at a time. There are some complex issues involved here, not the
least of which is the fact that 'conscious decision' is actually a physical contradiction
in terms if we take seriously what standard neurology tells us. Consciousness is about
knowing or having an input. Decisions are outputs. A unit with an output cannot be aware
of that output until it comes around again as input, and within the brain there is no way
that such a unit can know that it is receiving information about its own output rather than
that of another unit. An awful lot of intuitive assumptions need to be re-thought. However,
if each cell is an observer all the apparent contradictions appear to resolve themselves.
Neurobiology tells us that our brains are colonies of separate receiving units: brain cells. An
observer is a receiving unit. A receiving unit cannot have direct evidence of anything received
by another receiving unit. Just as none of us has direct evidence of consciousness in other
brains, no cell will ever have direct evidence of awareness in other cells. So the fact that
we do not feel ourselves to be multiple observers should not be a surprise. The existence of
other observers has to be inferred from logical argument of the sort given here.
Jonathan Edwards: email@example.com