Are
Our Spaces Made of Words?
Jonathan C.W. Edwards
Summary
It is
argued that both neuroscience and physics point towards a similar re-assessment
of our concepts of space, time and ÔrealityÕ, which, by removing some apparent
paradoxes, may lead to a view which can provide a natural place for
consciousness and language within biophysics. There are reasons to believe that
relationships between entities in experiential space and time and in modern
physicistsÕ space and time are quite different, neither corresponding to our
geometric schooling. The elements
of the universe may be better described not as ÔparticlesÕ but as dynamic
processes giving rise, where they interface with each other, to the transfer,
and at least in some cases experience, of ÔpureÕ or ÔactiveÕ information, the
mental and physical just reflecting different standpoints. Although this
analysis draws on general features of quantum dynamics, it is argued that
purely quantum level events (and their ÔinterpretationsÕ) are unlikely to be
relevant to the understanding of consciousness. The processes that might be
able to give rise, within brain cells, to an experience like ours are briefly
reviewed. It is suggested that the elementary signals that are integrated to
generate a spatial experience may have features more in common with words than
pixels. It is further suggested that the laws of integration of words in
language may provide useful clues to the way biophysical integration of signals
in neurons relates to integration of elements in experiential space.
Experiential
and Explanatory Spaces
It is still widely perceived within consciousness studies
that neither consciousness nor meaning in language (semantics/syntax) can be
explained in ÔphysicalÕ or ÔmaterialÕ terms (Chalmers, 1995; Preston and
Bishop, 2002). However, both neuroscience and physics provide reasons for
thinking that many of the difficulties involved may arise from a failure to
grasp the radically different nature of experiential space and time and modern
physicistsÕ space and time. We may also underestimate the link between these
spaces and language.
By space, we can mean either the space we experience or a
concept that physicists use to help explain how things come to be the way we
experience them.
This dichotomy extends to all aspects of the Ôreality of experienceÕ, as
distinct from what we think is Ôreally going onÕ (including when we are not
watching). The existence of a disparity is widely acknowledged, as in phrases
like Ôthe moon looks too big tonightÕ. However, as discussed later, this may
involve reference to yet another sort of space, geometric or Cartesian space
(of res extensa),
which most people use as their intuitive gold standard, once sufficed as
physicistsÕ space, but no longer does.
The
Case From Experience
We do not experience the world Ôas it isÕ, but rather as
our brains portray it to be. There is clear evidence that our spatial
experiences are based on models, or maps, concocted in the brain, that reflect
selected features of what is going on in the world (Smythies, 2003). It should
not be necessary to point to such evidence because it confronts us every day.
However, we intuitively compensate for inconsistencies and mismatches in these
maps, which is why it is useful to have formal psychological studies. The case
is summarised clearly in Ramachandran and HirsteinÕs paper ÔThree Laws of
QualiaÕ (1997), which gives a wealth of evidence from filled in blind spots to
disembodied heads. Rather than take up space reviewing the detail here I would
refer the reader to the original, since this is well-established ground. I
appreciate that some readers may still hold to a different view but would
nevertheless encourage them to read on.
The implications of this Ôspace concoctingÕ for our
understanding of reality need to be taken seriously. It is generally accepted
that nothing is intrinsically green. It can only tend to give rise to an
experience of green for a human with typical colour vision, by dint of a
certain reflectance spectrum. People may hold more firmly to the idea that two
things are Ôfar apartÕ, but far apart in experiential terms differs from far
apart in physicistsÕ terms in much the same way that the sense of green differs
from a green reflectance spectrum. Space may be a more pervasive aspect of the
world than greenness, but neuropsychological experiments indicate that
experiential space is just as much dependent on the machinery of experiencing
as green. And this is what we should expect. We have no basis for suggesting that brain
substance can re-concoct something with the Ôreal appearance of spaceÕ rather
than some analogy-bearing construct the appearance of which is primarily
dependent on the biophysical media the brain uses for its construction. We cannot expect the real
appearance of space to be floating about in the ¾ther ready for a functionalist
brain to latch on to at will.
My astigmatic right eye provides me with a concocted
spatial experience that illustrates two further points, one of which I will
expand on later. The lens in that eye makes light from a circle converge in the
way that a perfect lens does for an ellipse. With my corrective glasses on, a
round plate on a wall is round. Surprisingly, without glasses, the plate seen
through my right eye is still round. Yet, if I hold my glasses at a distance
and look at the plate, but not the room, through the glasses with my right eye,
the plate is elliptical, and I sense it as Ôseen through a lensÕ. But if I
convince myself that I see the plate directly, it snaps to the circle, as a
Necker Cube flips. With glasses ÔoffÕ my left hemisphere works as if it has a
lens inside it. With them ÔonÕ it does not.
Firstly, this example demonstrates that the issue is not
which appearances are real and which illusions. Which was the illusion? All
appearances depend on the way inputs are sorted at all stages up to the point
of experience.
Secondly, the fact that I have never noticed a
re-learning process since starting to wear glasses suggests something
remarkable about how the brain deals with shapes. It is very unlikely that the
relevant part of my brain maps a circle as a set of points each of which is
shifted just enough to make an ellipse each time I get the flip. (Optic nerve
input is constant.) It is much more likely that the map carries the messages
Ôsee circleÕ or Ôsee ellipseÕ and that these feed experience directly. This
should be no surprise since we know that messages like Ôsee edgeÕ arise in the
retina.
It may be
assumed that experiential space is 3-dimensional but it has been known since
the nineteenth century that it is not (James, 1890). We can see movement using parts of our retina that
cannot assess the distance involved in the movement. Just as things can be red now,
they can be moving now. We do not experience one space at one time; we insert time
into space. Experiential maps cross dimensions. As discussed below, our
experience has many dimensions, at least in the sense that it has dimensions at
all.
There are further layers to this discussion. We are
entitled to ask specific questions about how brains produce such useful maps of the outside world, as
long as these are considered maps based on correspondence of rules rather than
replicas. It is also important to note that a lot of experience is non-spatial,
as emphasised by Chris Clarke (1995), who has addressed several of the issues
raised here about space, if from a slightly different angle. Nevertheless, the
salient conclusion up to this point is that neuroscience supports the view that
searching for an answer to the question Ôwhat is physicistsÕ space likeÕ is
misplaced.
The
Case From Physics
It may be hard to accept that physicistsÕ space is not
ÔspaciousÕ, but modern physics involves radical changes to our concept of
space. Space is ÔcurvedÕ, in a way we cannot experience. It is inseparable from
time, whatever that might Ôbe likeÕ if it were. The space between an atomÕs
nucleus and its electrons was thought to be empty for a period around 1900 but
is now seen as neither full nor empty. More importantly, as discussed by
Douglas Bilodeau (1996), space no longer has the property that things are in
one part of it at one time. Space, time and probability are linked in a way
that defies the idea that we can envisage how Ôthis must have happened there
thenÕ. We have to analyse the world in an abstract dynamic way in which causality is more
than just a sequence of geometric frames.
So physics supports neurobiology. Rather than adhere to
the idea that physicistsÕ space is spacious like experiential space, logic
suggests that it is highly unlikely that physicistsÕ space should be thought of
as spacious in an experiential sense even if the thought were legitimate.
Ironically, these issues may have been easier to handle in 1700. Our problem
now is that schools hammer into us a debased form of Newtonian physics, frozen
in Cartesian geometry.
The
implication of the above is that appearances are connected by an aspect of
reality that, in itself, has no knowable, or even meaningful, appearance. This
aspect of reality is only known to us by inference, as sets of rules. This is not idealism because
these are not abstract Platonic rules. Rather, modern physicistsÕ reality comes
in the form of units (quanta) of operation of these rules, the number and type
of which can be determined under suitable conditions. There is apparent
reality, which
is undeniable to the individual subject but a partial and sometimes inaccurate
guide to what might be called connecting or process reality, which has no appearance, but
explains why appearances are compatible for all observers. These are not
internal and external realities. It is just that our only access to apparent
reality is internal and we are better at linking external, rather than
internal, events to process reality.
Two complementary realities may seem odd, but they have
been around a long time, even in the ordinary personÕs view. William James
(1890) notes: ÒStrange mutual dependence this, in which the appearance needs
the reality in order to exist, but the reality needs the appearance in order to
be known.Ó The dichotomy was familiar to Newton. He realised that his rules for
light and gravity required processes with no appearance generating appearances.
It is fairly easy, however, to pretend that these processes have appearances.
Quantum theory, however, has rules that defy appearances. Moreover, the
dichotomy is central to the theory. As such it is perceived as posing
paradoxes, like the Ômeasurement problemÕ. However, it may do so only because
the case from experience has not been absorbed. What is perhaps historically
most strange is that Whitehead (1929) was so dedicated to such a
process/experience view yet seemed not to capitalise on the new physics of his
time.
Geometric
Space: a Third, Fictitious but Necessary Space
I have indicated that neither experiential nor modern
physicistsÕ space is geometric space, which may come as a surprise and requires
clarification. Bilodeau (1996) contrasts the dynamic view of space, as the metric of
processes, with a geometric view of space with contents. The geometric view is
inadequate because it cannot explain the causality that modern physics
requires, if indeed it can explain process at all. In a sense it reduces the
world to a series of publicly accessible static three dimensional slices of
spacetime, which raise problems in both BohrÕs and EinsteinÕs theories. This
point goes back to LeibnizÕs time and is reflected in his Monadology (Woolhouse and Franks, 1998).
Leibniz rejected the geometric view for a Ômodern mechanicalÕ view, although he
also realised that ÔmechanismÕ could not ultimately be of an intuitive billiard
ball type and must be replaced by a Ôprogress in harmonyÕ with significant
similarities to contemporary physics.
Bilodeau also contrasts a dynamic account with a
Ôhistoric/ empiricÕ account of the world. The historic account is what is
provided by a ÔmeasurementÕ. A physicist needs both the dynamic account to
provide predictions and the historic account to test them. Indeed, Bilodeau
makes the claim that this is what Bohr meant by the distinction between ÔquantumÕ
(dynamic) and ÔclassicalÕ (historic/ empiric). It is not that some things obey
quantum dynamics and some obey classical dynamics. All processes must be
quantum-dynamic. Unfortunately, confusion has arisen because the word
ÔclassicalÕ is also used to describe the approximate Newtonian/ Maxwellian
dynamics to which quantum dynamics tends on a large scale through the
correspondence principle.
The historic account might seem to be an experiential
account, fitting with the process/appearance dichotomy described above, but
Bilodeau emphasises that it is not. His historic account is an objective
account in public language – like metres and seconds, with troublesome
dimension-crossing removed. It sounds suspiciously like a geometric account and
I think it is. Bilodeau admits that Ôthe metaphysical status of this mode may
be up for debateÕ. This would seem right in that appearances and processes seem
undeniable in their different ways but the geometric account may be no more
than a tool for interpersonal agreement, or the internal dialogue of considered
thought. It is essential for any scientific exploration (and so in a sense is
also a ÔphysicistsÕ Õ space), including that of consciousness, but maybe we
have confused the tool with reality.
Thus, the working model is that appearances exist in
experiential space and are linked by processes in modern physicistsÕ dynamic
space and that geometric spaces are attempts to marry a sanitised experiential
space with an explanatory space. These attempts have a bridging role, but no
claim to reality.
Sticking
to the Dynamic View (and Geometric Recidivism)
If reality has the two aspects of process and appearance
then the relationship between the two ought to be central to understanding
consciousness. Modern physics requires that the dynamics of quantum theory
underlie all processes, yet there are serious objections to explaining
consciousness at a purely quantum level. I am strongly in agreement with
BilodeauÕs view that models that invoke quantum level phenomena such as wave
function collapse or coherence are distractions. As I will argue further below,
it is the general framework of modern dynamics, involving the interaction of
distributed indivisible processes, which may allow a solution that a
ÔmechanicalÕ model cannot. Moreover, this can readily Ôshow throughÕ at a
traditional Maxwellian level via correspondence.
Perhaps the key problem with quantum theory is not that
it gives us an unfamiliar dynamic view of the world, but that people want to
keep a geometric view of process as well. They want to know Ôwhat things are
likeÕ between two situations in which interactions lead to appearances. What is
predicted mathematically is not disputed, but because the process linking two
such situations defies being given an appearance, people try to break it down
into sub-processes that almost have appearances. Although most physicists agree
that it is valueless to attribute appearances to the fundamental processes that
link observations, it is not always clear how completely this is taken to
heart. Bilodeau suggests that Bohr believed that the dynamic rules that link
appearances should not have any appearance. He suggests that several physicists, most
notably von Neumann, then back-peddled, creating the measurement problem.
BilodeauÕs account of BohrÕs views might be challenged,
but this is unimportant. Neuropsychology tells us that the refusal of quantum
theory to give appearances to the rules that connect appearances is not a
matter of pragmatics, it is good metaphysics and good biology. In BilodeauÕs
words ÔThe convoluted paradoxes of QM are really a road map out of our
ontological impasse.Õ If it has no meaning to ask what things are really like
in between Ôbeing like something to somethingÕ, i.e. generating an appearance
at the interface with another process, then the differences between the
ÔinterpretationsÕ of quantum theory have limited meaning. The two sub-processes
of von Neumann, the ontological interpretation of Bohm and Hiley and the many
worlds view of Everett (Barrett, 2003) are just attempts to impose appearances
on something which has none, or at least to try to hook up the dynamics to
appearances that cannot be. The predictions are the same; the mathematics is
equivalent. There may, nevertheless, be differences in heuristic power, as I
shall come to later.
Restoring
Homunculi
Before going further in trying to see how a dynamic view
might help to explain consciousness I believe we have to take one thing at face
value, even if problematic: the appearances of experience belong to something
inside a brain which has access to a pattern of internally pre-interpreted
information, including maps of external events together with elements from
memory, emotional responses etc.. We need a homunculus, or homunculi. And there
is no need for apology. Homunculi are often dismissed, but usually without good
reason. As Dennett (1978) pointed out, Ôhomunculi
are only bogeymen if they duplicate entirely the talents they are rung in to
explainÕ.
By homunculus I mean something in the brain
that receives converging signals not directly from the outside world but from
some internal ÔarrayÕ that maps the outside world. This involves repeated
transduction of signals from a state of a sensory receptor to a message-sending
form, back to another form in the array and again into a message-sending form
before reaching the homunculus, i.e. there is a regress or repetition. However,
this regress is only infinite, as Dennett implies, if every
time the message is passed on it gives rise to an array of exactly the same
physical form as the last. Nobody has ever proposed a homunculus in
such terms. Moreover, repetitive transduction is what brains are about. There
are arrays in the retina, in the brain stem, in the visual cortex and in the
parietal cortex but in each place the signals are in a different format. We
should be relaxed about there being many places in the brain with maps of the
world, with no infinite regress.
It may be
useful to indicate what I mean by information at this point. The existence of
several definitions may reflect a tendency to hit trouble when considering what
a homunculus might be. I shall later introduce a concept of ÔpureÕ or ÔactiveÕ
information to try to resolve these problems, but first I need to discuss
information in traditional terms. I will use the term at this point to mean a
feature(s) of a physical state of affairs for which a subject has access (is
informed), which is often, but not necessarily, a signal or
indicator of a
feature of another state of affairs with which it correlates in a way that the
subject can appreciate through interpretative rules. This definition (and
most?) immediately begs two questions. What is it for a subject (homunculus) to
have access to information (apperceive)? How does it have a set of rules of
interpretation? The challenge of these questions is again central to LeibnizÕs
metaphysics and I suspect LeibnizÕs analysis is a good place to start, whether
or not we call the rule-provider God.
What
Properties We Want From Homunculi
Rather
than ridiculing homunculi it is useful to review their putative defects. The
first is that repetitive transduction is a way of putting off facing up to the
impossibility of there being a final place where Ôthings come togetherÕ.
Information is handled in a brain in two stages. The first is segregative. The
eye and the ear segregate elements of information, which arrive in a
superimposed form, into maps or patterns of separate data points, as at the
retina. Further steps may involve re-segregation into other forms of maps but
at some stage there must be a process that does the reverse; where signals are
integrated, or brought back together.
It sometimes seems to be suggested that the information
is not Ôall brought togetherÕ. However, if this were so we would not be able to
respond to the relationships between bits of information – like smiling
in response to the pattern of a familiar face. For actions to be based on
patterns of information the elements of information need to be brought
together, or integrated, in one or more places, at least one being where we
experience things together. Although it may be unclear why integration is
associated with an experience it would be perverse to suggest that information
is integrated in one place for computation and experience of integrated
information arises elsewhere, unconnected to computation. Apart from anything
this would deny the possibility of talking about experiences.
What is likely to be true is that there is no single
place where things come together, because the brain uses parallel processing
with complex integration occurring in many places at once. Computers provide a
misleading analogy because everything comes together in one central processor,
but does so in a serial piecemeal fashion that would not be expected to give
rise to a complex appearance. The presence of many sites of integration in a
brain does complicate the relationship between computation and experience
(Edwards, 2006) but this is beyond the scope of the present discussion.
The second putative defect is the misconceived need for
an internal map to physically match the arrangement of the outside world in the
way that a screen, or a 3-D equivalent would: i.e. to be homotopic. Very
crudely homotopic maps do occur in
the cortex, but probably just as the simplest way of packing connections,
irrelevant to computation. Homotopy has no computational value because
homotopic arrays of signals present the same sorting problems as the source
from which they derive, with the added problem that in opaque brain they cannot
be accessed optically. They are DennettÕs bogeymen.
We are so used to the idea that maps are homotopic,
because their function is to present segregated data, that it is hard to
envisage what ÔmapsÕ involved in integration might be like. This is where the
question of how a subject has access to information looms large. A further
shift into counterintuitive territory is needed. Whatever the rules or dynamics
of Ôexperiential integrationÕ are they are unlikely to bear any relation to the
rules used to generate segregative maps, whether by means of lenses, or a video
camera. These maps used for integration are not going to be ÔanalogueÕ maps in
any familiar sense since no mode of ÔaccessÕ based on a traditional classical
geometric view of the world can address the Ôcomplexity within unityÕ that is
the binding problem of integrated phenomenal experience. This should not be a
surprise, since, if the information accessed by the subject is in forms like
Ôsee circleÕ, there is no way that we should expect homotopy or ÔanalogyÕ in
the laying out of signals for experiencing. This suggests that the ÔaccessÕ
that a homunculus has to information may need to be understood in a new sort of
framework with the distributed features of the fundamental dynamics of modern
physics.
Difficulties
with Receiving
Because of the difficulty of understanding how
information is accessed or received there appears to be a fashion for denying that
information needs to be received, despite the clear assumption of conventional
neuroscience that it does (and the cell activation that sends an action
potential down an axon only ÔfunctionsÕ as a signal if the potential arrives
somewhere). In their essay on qualia, Ramachandran and Hirstein (1997) suggest
that if person A experiences red, then careful connection of their brain by a
Ôneuronal bridgeÕ to the right spot in the brain of person B, who is colour
blind but has the brain tissue needed to experience colour, will ensure that B
experiences red; i.e. a bit of B receives red.
Receiving is needed to make sense of the story. Yet the
problem of meaning in physical systems arises here. The suggestion seems to be
that experiential red is carried by brain cells in a language that is
accessible to other brain cells, and that experiential red is only ÔprivateÕ
because B does not know how to translate the word red into cell message
language. This may be true in one sense, but in another sense brain cells do
not have a language for their messages. All messages consist of the same action
potentials.
The meaning of red must lie entirely in the relationship
between the physical arrival of the message and the properties of the brain cell at
which it arrives (highlighting the importance of brain substrate, and
supporting the ÔtissueÕ (versus functionalist) view espoused by Jeffrey Gray
(2002)). We can only assume the message will be AÕs ÔredÕ if the receiving cell
in brain B has exactly the same physical properties, including the position and
excitatory properties of the point where the neuronal bridge is connected, as
its counterpart in brain A. (For the difficulties encountered when considering
more than one cell, see Edwards (2005, 2006)). These things may one day be
knowable but privacy of experience is more robust than Ramachandran and Hirstein
imply. This brings us to the problem of how a subject can have rules of
interpretation that allows it to receive information in a useful way. Something
in the nature of a receiving unit must carry with it such rules.
So how might a dynamic analysis resolve these issues of
integrated richness of access and intrinsic rules of interpretation?
The
Indivisibility of Fundamental Processes
The main attraction of a dynamic view for explaining
consciousness is that fundamental processes are distributed in time and space
and can have enormous indivisible richness. This is not particular to oddities
like Bose-Einstein condensates, which are, if anything, rather isolated and
uniform. It also has nothing to do with the concept of wave function collapse,
which appears to have been introduced to salvage a quasi-geometric account of
the otherwise ÔunvisualisableÕ[1].
The indivisibility of a fundamental process is a much more general concept,
perhaps most elegantly illustrated by Richard FeynmanÕs lay description of
electromagnetism in ÔQEDÕ (1985). Crucially, it is an indivisibility of process, not of ÔstateÕ.
As an example, consider a radio wave passing from a
transmitter to my television aerial through air encumbered by tall buildings,
leading to ÔshadowsÕ in my TV picture due to diffraction by the buildings. This
process is indivisible, is as large as one might like, cannot be described
purely geometrically, but can nonetheless be analysed without recourse to
quantum formalism. All we need is for consciousness to involve the same
everyday features.
What is interestingly indivisible about fundamental
processes is their interaction with other processes; diffraction of a radio
wave by buildings is an indivisible process distributed in space and time.
These fundamental causal interactions have no ÔmechanismÕ. There is no
mediator, the processes simply progress in harmony, as Leibniz proposed.
Nothing pushes or pulls; pushes and pulls are just the most intimate harmonious
processes (e.g. radio waves). All that is exchanged in these interactions is a
pattern of probabilities that so-and-so will appear to be so: in other words,
pure information, or, as Bohm and Hiley (1995) described it, Ôactive
informationÕ. Passage of information is ÔdeterminacyÕ: not a state of a thing,
but a ÔknowingÕ about one process by another process. The knowing is always
partial and known to some particular process; processes are not either
ÔdeterminateÕ or Ônon-determinateÕ. Moreover, modern physics requires that once
an aspect of a process is ÔknownÕ through such an interaction it is
irrevocable. There is nothing special about brains in this respect; once a
machine has acquired information about a process that aspect of the process can
never be knowable otherwise.
Modern physics tells us that the fundamental elements of
the universe, are instances of the operation of rules which determine the
likelihood that one appearance will follow another: rules that operate on information
from their environment that modulates, or informs, probabilities. Moreover, the amount of
information available to these elements is large. As Feynman (1985) pointed
out, a photon of sunlight reaching my eye, having been reflected off a lake, is
informed about the entire lake, not to mention the surface of the moon on some
days. We are used to information coming in discrete ÔbitsÕ in a classical
geometric framework, with each bit relating to one interaction in one place at
one time. However, physics tells us that this is just the correspondence
principle operating when countless processes are considered together. Bohm and
HileyÕs pure, active information, works in a quite different way.
The
Subject as Fundamental Dynamic Process
To capitalise on this availability of a rich, indivisible
pattern of information, we need to propose that a human experiencing unit, or
subject, is itself a fundamental process. This should not be too hard to
swallow, since there is nothing else for it to be in the dynamic view. A
subject in a brain should access information the way an x-ray passing through a
crystal does, and responds accordingly. By definition, fundamental processes
carry with them sets of interpretative rules, at least in the sense that they
ÔknowÕ how to respond; perhaps the most remarkable aspect of all physics. They
are instances of operation of such rules. So an appearance should not be a
description of such a processes, but a pattern of informational elements passed
to a process (subject) by other processes at their interface. BohrÕs
complementarity, which separates appearance and process, is to be expected, not mysterious.
Casting the subject as a fundamental process may be
unfamiliar. It is usually cast as a ÔclassicalÕ object, but in BilodeauÕs
interpretation of BohrÕs usage it is not. Classical ÔthingsÕ are just marks in
the sand (Ômeasuring devicesÕ) used for confirming dynamic realities.
Nevertheless, we need to find a fundamental process that
could be a subject in a brain that is unitary and demarcated, with parameters
that allow it to access the right sort of information, and coupled to a
biologically relevant outcome. Modern physics seems to suggest that a
fundamental dynamic process ought to be a mode of oscillation that can be
occupied by one or more quanta of energy. Detailed discussion of the options
for a Ôhuman subject modeÕ is beyond the present scope but elsewhere (Edwards,
2006) I have argued that the candidate that fits the above requirements best is
an elastic (phononic) mode occupying the dendritic tree of a neuron with a
wavelength close to the distance between synapses, coupled to trans-membrane
electrical potentials. Neuronal dendrites are where we know information is
integrated and such a mode would have access to many thousands of informational
elements simultaneously. A recent reassessment of neuronal membrane excitation
suggests that it is critically dependent on coupling to an elastic wave
(Heimburg and Jackson, 2005) at least for action potential propagation.
Anaesthetics may remove experience because they decouple the elastic wave by
altering the melting point parameters of the membrane. This suggests that there
would be nothing epiphenomenal about such a basis for consciousness; it would
be essential to neuronal function.
The idea that human subjects might be features of the
membranes of individual cells seems to worry people, although this may be more
an emotional than a scientific problem since it appears to raise no conflict
with what we know, just with what we tend to assume (Edwards, 2005; 2006). It
is possible that a fundamental physical process can occupy the dendrites of
several cells but current dogma is that the neuron is the functional
integrating unit in the brain. Further discussion below leaves this as an open
question, but a single cell model does appear to be more tractable and
therefore potentially more productive.
Is
Experience Made of Words?
The puzzle that this model leaves us with is that
although current physics can give a third person account of how fundamental
processes might interact at sites of integration of information in the brain,
it tells us nothing about how these rules might translate into experiential integration. How is ÔcircleÕ
integrated with ÔblueÕ to produce a blue circle? For the concept of interplay
between dynamic processes and appearances to be of practical value, we need
some clues as to how to approach the problem from the experiential side, to
provide some predictions about what might match with what. We need clues to how
experiential space might Ôbe constructedÕ, to use a potentially dangerous
metaphor in the absence of anything better.
In 1972, Horace Barlow (1972) made some suggestions about
the number of elements of information required in various parts of the brain
for a human percept. The suggestion was that an experience would be composed of
about a thousand elements of information, which Barlow portrayed as, Ôlike
words, having the special property that they lead to an economical
representationÕ. Thus, although Ôa picture is worth a thousand wordsÕ, a
thousand words (~5Kbytes) would carry information more economically than the
necessary array of pixels (?~1Mbyte). In BarlowÕs concept each element of
information was associated with the firing of a cell; Ôan active neuron says
something of the order of complexity of a wordÕ.
I suspect this suggestion contains a profound insight.
However, Barlow says nothing about how these word-like elements Ôlead to an
economical representationÕ. What ÔhearsÕ this ÔsayingÕ; i.e. how do the words
combine to form the picture? How does blue get with circle? There would seem to
be only one neurologically tenable answer; action potentials from these 1,000
cells must be sent down axonal branches to converge on the dendrites of a
receiving neuron – or indeed through many branches to many such neurons.
A thousand signals is well within the input capacity of some cortical neurons
with ~40,000 dendritic synapses. (A variant is that signals behave more like
letters than words, which is still economical, but implies different sorts of
rules of interpretation.) It is perhaps ironic that although it is frequently
assumed that experiential integration occurs over a large ÔnetÕ of cells,
orthodox neurophysiology, based on the Ôneuron doctrineÕ, requires integration
to occur only within individual cells. The frequently assumed picture is a
violation of a doctrine based on a century of experiment. My own view is that
the neuron doctrine is sound (Edwards, 2005, 2006).
What seems of key interest here is that without this
assumption of signals that combine with the unusual economy of words, it is
hard to see how a brain could integrate the elements of an (at least visual)
experience. This bears on the circle-ellipse flip mentioned earlier. It
suggests that experience may be synthesised from elements more like words than
pixels. As with Ôfive red rosesÕ this allows a single colour signal somehow to
be bound to five separate shapes and not the gaps between.
Dimensions
and Degrees of Freedom
Understanding how appearances could be built out of words
runs into the problem that the physical basis of word combination, or syntax,
is itself a major mystery. Chomsky (2000) has implied that unlocking it is
probably beyond our current capabilities. However, one or two people have
considered taking up the gauntlet. The way words combine involves peculiar
properties in which elements ÔbelongÕ to each other in various different ways.
Hinzen and Uriagereka (2006) have suggested that this implies that individual
words have values in more than one dimension and may interact in a way best
described by a matrix based algebra, which allows for complex and asymmetrical
relations between elements.
The idea of words existing in, say, five dimensions, may
seem fanciful, but only if we remain tied to a geometric view of the world. In
a purely mathematical dynamic view dimensions are simply independent degrees of
freedom. Modern physics ascribes considerably more degrees of freedom to
processes than just position and time.
Mathematical treatments of fields using vector or matrix based algebras
may invoke very large (potentially infinite) numbers of degrees of
freedom.
There is no shortage of degrees of freedom available in
the brain. A neuronal membrane with 40,000 input synapses can be considered as
a field with 40,000 degrees of freedom. Creating a 17-dimensional experience out
of this is not a problem in terms of capacity. In a sense what needs explaining
is how a system with 40,000 degrees of freedom gets interpreted in terms of
what seem to be a relatively small number of dimensions. This should depend on
the way the input is ÔreadÕ. A hologram may provide an analogy. A hologram can
be considered as a field of countless degrees of freedom or as an array at a
surface with two, spatial dimensional, degrees of freedom. However, if probed
by the right sort of optical beam a third dimension is retrieved because the
probing beam applies a registrational rule to the elements in the hologram that
detects a phase relation. Another example is an Ôinformation stringÕ on a
Turing machine tape or optical disk, which can be interpreted in whatever set
of dimensions the registrational rules of a piece of software are designed to
ÔextractÕ it in.
Thus pure information accessible to any fundamental
process would be expected to have an effective number of degrees of freedom
determined by the number of degrees of freedom of the field that is this
processÕs environment of many other Ôapperceived processesÕ and whatever
registrational rules are inherent to the apperceiving process. In terms of the
causal chain involved in such an information-passing interaction, and the
externally observable results, we have a good idea what the registrational
rules must be. They should be the rules of modern field theory. We simply need
to know what the parameters of the relevant fields and modes are.
What is a much harder issue is how these rules of process
might relate to rules of interpretation that determine the qualities of
appearances where processes interact, and Ôapparent dimensionalityÕ.
Analysis
from Within
This brings us to a completely new sort of scientific
question. There may be another half to physics, an experiential half, to keep
us busy for a few centuries. And trying to transpose the rules of third person
ÔprocessÕ physics to first person ÔappearanceÕ physics is likely to create a
minefield of false analogies. Almost certainly, correspondence between the two
needs to be considered in abstract mathematical terms without being bound by a
geometric framework. We need to beware questions like Ôwhy should a phononic
mode interacting through a pattern of potentials across a membrane actually
have a spatial experienceÕ.
This would be putting things back to front, missing the point that physicistsÕ
space is not spacious in the experiential sense; that is just a feel you get
inside a brain. It would be just as inappropriate to think that a photon
passing through YoungÕs slits would experience our spatial view of slits.
Everything has to be thought of Ôfrom the inside outÕ, which is far from easy.
There must be a pattern of electrical perturbations in
the dendrites of one or more cells that carries a code that is interpreted as
the experience of an imagined green silk scarf. Neuroscience requires that.
Perhaps we need to recognise just how clever fundamental processes are at
interpreting incoming information. They progress on the basis of effortlessly
following the interference pattern of an almost infinite number of path
possibilities. Why should they not be able to convert an array of about 200
points of ÔblacknessÕ (path impossibility) into the thought Ôgreen silk scarfÕ.
After all, even if in a more indirect way, this is exactly what has happened
between your retina and somewhere in your brain just now. And it is the final
receiver that must do the interpreting; nothing else makes sense.
One foothold we have is that it seems reasonable to
assume that the way a field of informational elements is handled in terms of
degrees of freedom in process terms matches up in at least in some way with the
way it is interpreted experientially. This seems to be required if experience
is to bear any relation to behaviour, which it does. In fact the brain might be
thought of as a machine that harnesses experiential integration at the
fundamental level to guide behaviour in a macroscopic composite world.
Yet, two uncertainties emerge. Firstly, it is not clear
how well the hologram analogy holds when considering the internal picture. In a
hologram the probing beam converts a field from a two-dimensional array to a
three dimensional shape, in terms of the information passed on to another
observing process,
but we have no insight into what the probing beam might experience. Secondly,
it is not clear that experiential space really comes in dimensions. The
Penrose/Escher staircases show that we can think we are experiencing in three
dimensions when in fact there is no overall dimensional framework. (Perhaps
germane to ClarkeÕs (1995) argument that experience is not inherently spatial.)
We have a set of relations, each of which makes sense, but which, taken as a
whole, are impossible. This is again akin to language where it is possible to
have a narrative, in which the words and sentences make sense, but which, taken
as a whole, is self-contradictory. Experience is probably consistent most of
the time because it is a best guess narrative constructed by the consensus of
millions of parallel operations in input pathways sifting through for the most
consistent relations (Ôcircle seems the best betÕ). These operations have
usually got things sorted before experience but sometimes a false association
is made.
Moreover, these relations often seem to have more to do
with the ÔbelongingÕ relations of language than geometric relations. A car is
perceived as having all sorts of non-spatial features, like solidity, potential
motion, kudos, age, environmental unfriendliness. These relations certainly
involve many degrees of freedom, but perhaps they are not sorted into
ÔdimensionsÕ.
Nevertheless, it does seem necessary to propose that
information is stratified in some sort of way within an experience, so that
elements are interpreted as Ôthis or that sortÕ whether the sorts be shape,
colour, movement or whatever. The integration of these sorted elements is then
a matter of the subjectÕs Ôexperiential syntaxÕ. One or more processes inside a
head must have an internal language, a sort of inbuilt Chomskyan I-language
(Chomsky, 2000) of thought, with a vocabulary that includes line, circle,
ellipse, red, blue, etc. Incoming signals are read in this vocabulary. The
signals may have meaning individually or their relations may have meaning. Thus
a signal at a synapse may mean red, or may be more analogous to ÔrÕ.
What does seem to be a basic requirement of a set of
registrational rules generating an experience, if we genuinely believe our
experiences are unified, is that it must be able to sort sensory elements from a hierarchy of relations
between elements
and then build an interpretation that uses both appropriately. This is
essentially what a language faculty needs to do, binding the percepts of
Ôphonetic formÕ (the sound or shape of the word cow) and referent (an image of
the animal) through a relation involving the semantic content or Ôlogical formÕ
of the word and then binding each word to others through syntactic relations.
To discover the rules of experiential syntax may be an
impossible task. However, the message sending system that is a brain must,
presumably, to be useful, complement such an experiential syntax according to
rules that may be at least broadly derivable. Thus the function of the brain,
whether it be language, mathematics or any form of thinking, should involve the
interaction of two complementary rule systems, one at the fundamental level and
one at the composite level of neural networks. In the past interest has focused
on connections and network systems, but the rules of integration must be at
least as important.
The parts of the brain dealing with language may be
unusual, but the evolution of human language occurred too fast to require major
genetic changes. It is not unreasonable to suggest that the way the elements of
language are integrated reflects some fairly basic aspects of how information
is integrated in neurons. In the Chomskyan programme (Chomsky 2000) most of the
rules of language have been whittled down to one basic process called ÔmergeÕ;
in other words, integration. Very simply (at least on the face of it) ÔlovesÕ
merges with ÔMaryÕ and then with ÔJohnÕ to form ÔJohn loves MaryÕ. Although
this has been described in terms of Ôinclusion in a setÕ there are features
that suggest that it may be much more like a matrix operation (Hinzen and
Uriagereka, 2006). If the defining parameters of such an operation could be
expressed mathematically then we might have an idea just what we should expect
neurobiophysical processes to explain. Hinzen and Uriagereka (2006) suggest
that words need four hierarchical degrees of freedom (for nouns: abstract <
mass < count < animate).
That is an important start.
Thus, there may be legitimacy in seeing the problem of
syntactical merge as the same sort of problem as the binding problem of
experience. The caveat must be that any integrative processes going on outside
of experience (at least the sort we are used to discussing) may well be a
composite process involving piecemeal integration at lots of different sites in
series or in parallel, as much dependent on the pattern of connections as on
individual fundamental integrative events. Nevertheless, the semantic/
syntactic rules of these fundamental integrative events ought to play an
important part in determining the overall rules of the system.
There might also be clues derivable from neuronal
microanatomy. Fundamental processes can have parameters that translate directly
into classical geometry – like the phononic modes that occupy ice
crystals, with sixfold symmetry and multiple nodes in each arm. Phononic modes
in neuronal dendrites could similarly have parameters relating to the branching
manifold nature of dendritic trees. However great the gap between biophysics
and experience may currently seem to be there are reasons for thinking that the
rules governing the relationship between relevant parameters should be rather
simple, just as the genetic code turned out to be remarkably like an alphabet.
Finally, it needs to be noted that the processes of
signal sending and integration are going on in many places in the brain at
once, each place dealing with a different level or stage of the total process
of perception. The access to information that in the proposed model constitutes
our Ôverbally reportableÕ experience will presumably occur at only one of these
many levels or stages. That need not imply privileged metaphysical
(experiential) status at this level; it simply implies reportability. This
illustrates how cautiously one has to proceed.
Synthesis
In summary, it is proposed that there are two
complementary aspects to reality: processes, and, at their interfaces,
appearances. Processes have no appearance, but are instances of sets of rules
operating on other processes. For fundamental processes, operation of these
rules is indivisible, whereas composite processes are divisible into component
processes and, as such, tend to fit into a Ôclassical geometricÕ view. Pure, or
active, information, which forms the basis of appearances, is exchanged between
fundamental processes in a non- mechanical way, although in composite processes
information may seem to be carried mechanically. The rules that are fundamental
processes determine both the way these processes evolve, as observed from
ÔoutsideÕ and described by current physics, and the way each process interprets
its interactions with other processes as an appearance. Fundamental processes
interact with fields with very many degrees of freedom. The way these degrees
of freedom are assigned to ÔdimensionsÕ from within is something we do not yet
understand, and may prove intractable, as in the ÔmysterianÕ view. However, it
may prove accessible through inference from mathematics and language.
The suggestion is made that the way these rules handle
degrees of freedom in constructing visual or other experiences may be much
closer to the rules of language syntax than might first appear. Experiential
space is not built of little Lego
ÔspacebricksÕ (as
if we had any reason to think it was) but more the way a sentence is built. We know that fundamental
processes have stupendous powers of reading and integrating possibilities.
There seems no reason not to think they might handle things like sentences.
Even the invisible mathematical rules of the space of processes might be said
to be more like language than schoolroom geometry.
It has been suggested (Hinzen and Uriagereka, 2006) that
our mathematical capacity, which, as indicated by Alfred Wallace, emerged
without apparent evolutionary drive, may be a by-product of language.
Linguistic operations can be reduced to mathematical operations in abstract
terms. A slightly different proposal, based on BarlowÕs suggestion, might be
that brains use word-like operations, with matrix-like aspects, in constructing
and using ordinary experiences, as of a round or elliptical plate. Words and
numbers may have, in a sense, already been there. A relatively minor change in
neuronal dynamics may then have led to the option of using these same
operations in a more abstract way, giving rise to both linguistic and
mathematical faculties.
The practical implication of this synthesis is that it
may be valuable to focus efforts on identifying exactly what the domains of
integration of pure information relevant to experience in the brain are. The way
they behave may then be open to study both in process terms, through
biophysical experiment, perhaps involving the actions of anaesthetics, and
experiential terms using inference from language itself. Just as neurology
might one day tell us how language works, language might also tell us something
about how brain cells work.
Acknowledgements
I would
like to thank Paul Marshall, Basil Hiley, Wolfram Hinzen, Juan Uriagereka,
Chris Clarke, Horace Barlow, John Smythies and many JCS online subscribers for stimulating
input in various forms, and Douglas Bilodeau for the clarity of his 1996
article.
References
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[1] Despite the popularity of a link
between wave function collapse and consciousness, such a link raises a number
of difficulties, including:
1. In
BohrÕs original theory, observations of the initial and final conditions of a
quantum system were linked by a single process, contingent on both observations. Von Neumann
divided the process into two, the second being a collapse from many possible
ÔstatesÕ to one. This may help ÔvisualisationÕ but introduces an arbitrary
ÔeventÕ, at the second observation for which we have no evidence.
2. Wave
function collapse looks to be the least interesting part of quantum theory, its
ÔcontributionÕ being random and expected to be lost in a biological
system.
3. The
original idea that Ôconsciousness collapses wave functionsÕ conceals a logical
error. Bohr gave rules for processes that link experiences. Since we do not
have experiences in other peopleÕs heads we cannot ascribe a special ontological
interruption to what goes on there even if we might to our own experience.
4. Wave
function collapse is said to make things ÔdeterminateÕ. This begs the question
of what being determinate to what. Being determinate is about one thing being
known to some other thing. There is nothing in quantum theory that says it is
an intrinsic change of state of something. This is the geometric illusion
again.
5. If
part of my brain Ôbecame determinate to itselfÕ, what would that mean? Would
the determinate state be a static snapshot or include dynamic features? Quantum
theory does not say Ôparticles know themselves when the music stopsÕ. It just
says that when we observe something it has a ÔparticulateÕ quality.
6. von
NeumannÕs approach allows the Ôsuperposition of statesÕ of, say, an electron,
to continue as part of a greater Ôsuperposed systemÕ right through to the point
of the ÔcollapseÕ of conscious perception. But what links the collapse of this
electronÕs wave function to those of all the other things we are seeing at the
time?