MIND AND BRAIN
|
| Information Processing |
NOTE 1: by "matter" we understand
a metalanguage shortcut to the physical concept
of discretized, integrated high density areas
of Gravity/Inertia Field. Inverted commas
stress its contrast to the common so called
materialistic usage of the term, which denotes
a meaningless abstraction void of physical
sense and absent from physical vocabulary.
In the chapter "PHYSICAL CONSTRUCTS"
we asserted:
*** A particularly pernicious pseudo-physical
term is "matter". It does not appear
in any physical formula even as an auxiliary
concept or its metalanguage alias, i. e.
there is no such physical term. Nevertheless,
one should be aware that it's commonly used
as a metalanguage shortcut, as a collective
name for "discretized high density field
areas", aka "particles".
*** Concurrent physics sees phenomena in
the general form of C/D polarity of continuous/discrete
aspects. In order to comply with the common
usage we shall use "matter", indicating
with inverted commas its meaning of discrete
aspect of involved phenomena.
NOTE 2: In the context of the C/D polarity,
Mind and Brain are respectively continuous
and discrete polar counterparts, the P-Equivalent
aspects of the phenomenon "reflection".
"Brain" is an abstract structure
justified, as all abstractions, by its capacity
to coordinate particular "neurological"
events and their associations with P-Equivalent
"psychological" events, both mental
and immanent. Some unbridled neurologists
and pseudo-philosophers reify "Brain"
to a transcendental "real object"
promoted to the utmost foundation of the
phantasmagoric human view of the "World
Out There". In the present chapter we
shall substitute for "reflection"
its technical synonym "information processing".
Information Processing may be schematized
with help of three entities: Processor, Input
and Output. Input, a set of Receptor devices,
feeds the Processor which generates Output,
a set of action Trigger devices, fed partially
back to the Input as the cybernetic feed-back..
Within this schema and in an arbitrary -
not preprogrammed or memorized - situation,
action involves the perceptional- motor coupling,
i. e. relating all Receptor/Trigger couples,
in order to select those pertinent to the
particular act.
Now, discrete "material" Processor
cannot exceed 2*10e47 operations per gram
and second (Bremermann's limit[*] (BL)).
Enormous as it may seem, it turns out to
be negligible.
2*10e47 is a small number when compared with
processing rates that one would need to carry
out certain search processes. For example,
Minsky gives the number of all possible move
sequences in chess as about 10**120.
Conservatively estimated Input and Output
of an advanced organism contains 10e6 devices
each. Supposing simplest 2 state devices,
relating Input with Output requires R=2**(2*10e6)
operations. Its Log=602060, indicates R to
be
1 with 602060 zeros. On the other hand BL
for a kg (roughly the mass of the brain)
is about 2*1e50 or 1 with 50 zeros. Dividing
R by BL we get about 1 with 602010 zeros
seconds as the lowest limit of time required
by discrete "material" brain to
relate conservatively estimated input and
output of an organism. The practical "synaptic"
limit[**] is by about
34 orders longer, because the neuron structure
of the brain is much courser than the atomic
granularity implied by the BL.
Thus, Morphogenesis, behavior of living Organisms,
Human complex scientific and social Projects
clearly require some additional agent different
and incomparably faster than the raw discrete
"matter", let alone the real neural
brain.
MIND, BRAIN AND THEIR INTERFACE
Mind
The chapter "STRUCTURES OF MIND"
postulates a Structure homomorphic with the
"Three Worlds" of Ref1, encompassing
three domains: Sensorium, Imagery and Symbolics,
accounting for Mind's functions, such as
perception, imagination, cognition, symbolizing,
inference, reflection and understanding
Brain
Brain's structure pertinent to information
processing encompasses specialized cells
called Neurons and their interfaces called
Synapses. A neuron consists roughly of several
dendrites, of a cell body and an axon. Dendrites
are receptors of electric impulses which
travel through them to the cell body and
make it "fire", sending electric
impulse further down the axon till axon terminal.
Axon terminal lies close to dendrites of
neighboring neurons, separated from them
by synapses. A synapse consists of:
1. a presynaptic ending that contains neurotransmitters,
2. a postsynaptic ending that contains receptor
sites for neurotransmitters and,
3. a synaptic cleft or space between 1 and
2. Neurotransmitter is a chemical released
by impulse reaching the presynaptic ending
at the axon terminal and travelling through
the cleft to the postsynaptic ending in vicinity
of a neighboring neuron's dendrite. Neurotransmitter
reaches the dendrite and triggers an electric
impulse that travels down to the cell body
of the neighboring neuron which in turn may
fire. This network structure of neurons-vertices
and synapses-edges allows millions of neurons
to "talk" with each other. However,
it would imply so far chain reactions in
which a single impulse will fire the whole
network rather than create any local pattern.
That's why we have two sorts of neurotransmitters:
activating and inhibiting. The receiving
neuron "counts the votes" and decides
to fire in case of sufficient "activating
majority" or else to stay idle. While
freely stretching an arm, the triceps contracting
neurons will get activated, while those of
the biceps inhibited in order to relax the
opposite bending force. In controlled stretching
both activations and inhibitions will be
precisely measured out to achieve the desired
action. Neurons are connected so that when
they fire together, they "wire"
together, to form stronger synaptic connections.
This is the Brain's dialectic counterpart
of Mind's Learning faculty defined above.
Brain-Mind interface
We have seen that discrete "material"
processor of the size of human brain would
need about 1e600000 seconds to process the
Information involved by a simplest action
of an advanced organism. This is a hypothetical
limit of what the evolution may reach in
another billion years. The practical limit
of brain's neural network by itself is about
1e900000 seconds.
Consequently, the discrete "material"
Brain, including its neural network structure
cannot account alone for human and living
organisms' behavior. We must look for some
continuous aspect of Brain as Interface supporting
covariant maps to such Mind's functions as
Reflection and Inference.
Field suggests itself as the most fundamental
Continuum. Brain's neural network clearly
"generates" electromagnetic field
and many Neurologists see it as Mind itself,
or at least as Brain's interface to some
other, as yet undefined, but clearly observable,
thus physical "Mind". This question
exceeds the scope of our essay. We stop at
the assertion that human behavior posits
a polar continuous counterpart of the discrete
Brain and that the EM field satisfies this
requirement.
Another, more complex and rather exciting
theory proposes Field generated hologram
as interface to Mind, or Mind itself. Hologram
has many striking features, starting with
Totality being in each Part. Some Neurologists
claim that memories are not stored in any
specific location in the brain, but appear
to be distributed over the whole brain, much
as any portion of a holographic image is
distributed over the whole structure. Suppressing
a part does not change the anything in the
image, else than making it fainter. The dynamic
TimeSpace of the holographic image is homomorphic
with our Imagery structure and could eventually
support its patterns. Again, like in the
case of Field, the question of hologram being
"Mind", or an interface to some
as yet undefined "Mind", exceeds
the scope of our essay. We shall stop at
saying that hologram may satisfy the requirement
of a polar continuous counterpart of the
discrete Brain.
We shall just mention here a rather poetic
theory of pan-hologram based on "holographic
paradigm". A small group of researchers
sees "real universe" as a holographic
blur of frequencies and the brain also as
a hologram which selects some of this blur's
frequencies and transforms them into sensory
perceptions. In this "ocean of consciousness"
we would be the "weary rivers that wind
somewhere safe to sea". There is a striking
affinity of this paradigm with religions
of the East which have long upheld, the physical
world is Maya, an illusion, and although
we may think we are physical existants moving
through a physical world, this too is an
illusion. Most, if not all protagonists of
the paradigm are attired by eastern beliefs,
include the paranormal in their inquiries
and some report about shamans making instantly
disappear and reappear entire groves of trees.
Let's note that so far we have justified
the need of some covariant continuum with
consideration of the processing speed. Another
necessary justification is provided by the
Morphogenesis. Whether we consider it from
the point of view of Haken's Synergetics
or Thom's Catastrophes, it consists in ordering
a continuum.
Final note
Brain and Mind structures described above
are Models satisfying all Model requirements,
including falsifiability.
Brain-Mind Interface, perhaps the most exciting
area of inquiry, produced so far only Theories,
i. e. deductively consistent structures lacking
factual falsification.
References: Ref1: Popper and Eccles "The
Self and Its Brain"
(Springer International) Page 327, Fig E5-7,
etc.
[*]BREMERMANN'S LIMIT
No discrete "material" system whether
artificial or living can compute more than
2 x 10e47 bits per second and per gram of
its mass. This limit refers to a self-contained
system where the power supply is included
in the "matter" and where "computation"
is defined as the transmission of information
over one or more channels within the system.
Recognizing that computation requires energy
for changing physical markers and for recognizing
such changes in subsequent steps, the limit
is obtained from Einstein's relation between
energy and "matter", E=mc2, and
Heisenberg's uncertainty principle, which
specifies the inaccuracy or noise in the
measurement of energy. Current computers
as well as the brain are far from approximating
this limit because they don't utilize atomic
events for the storage and transmission of
information.
Ref2: Bremermann's paper
OPTIMIZATION THROUGH EVOLUTION AND RECOMBINATION*
H. J. Bremermann
Part I. Limitations On Data Processing Arising
From Quantum Theory Part II. Evolution Processes
and Optimization
Part I is pertinent to the derivation of
the limit and to its implications for the
Mind-Brain issue.
[**] BRAIN'S COMPUTATIONAL POWER
The total computational power of the brain
is limited by several factors, including
the ability to propagate nerve impulses from
one place in the brain to another. Propagating
a nerve impulse a distance of 1 millimeter
requires about 5 x 10-15 joules. Because
the total energy dissipated by the brain
is about 10 watts, this means nerve impulses
can collectively travel at most 2 x 10e15
millimeters per second. By estimating the
distance between synapses we can in turn
estimate how many synapse operations per
second the brain can do. This estimate is
only slightly smaller than one based on multiplying
the estimated number of synapses by the average
firing rate, and two orders of magnitude
greater than one based on functional estimates
of retinal computational power. It seems
reasonable to conclude that the human brain
has a raw computational power between 10e13
and 10e16 operations per second
|