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Biological Systems
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| 03/02/05 |
| The Cell as a System
The cell is the fundamental construct of
living systems. It is the common building block of all living
tissue and the foundation for all living systems, without
exception. In many ways it is the best example of a prototypical
system that we can conjure up, and it is in many ways the
epitome of natural self-organization. Indeed, general systems
science really had its birth in the concern with holistic
perspectives upon cellular function and development, at a time
when the internal organization and happenings of a cell were
still pretty much a mysterious "black box." We need
only consider how remarkable cellular evolutionary development
has been, when we realize that all living organisms have been
basically the descendants of a continuous, non-stop process of
cellular growth, reproduction and division from the first
proto-biotic cellular formations, and it is possible that all
life might have originated from a single successful cellular
system. I return to the examination of the cell as a system, for
beyond ecology, what little formal biological study I've had has
been focused upon the cell. A systems
based perspective upon the cell therefore would be based upon
not only the examination of the metabolism, behavior and
life-cycle of a cell as a prototypical biological system, but
upon what can be called "cell ecology" and properly
"cellular meta-biotics" or the nature of
inter-cellular interactions that influence the outcomes of
microbial development and evolution. At some point, microbial
populations would begin exerting a significant influence upon
their environment, and begin altering their bio-geophysical
contexts in the direction that encouraged further evolutionary
development taking place. In spite of the
self-containing environment within the cell membrane, all cells
exhibit specialized environmental adaptations. They exist in
rather special and narrow contexts of cell development, that
define the limits of their growth and development. Under
normal conditions for a cell, a cell can be expected to respond
to its environment by growing in population to the natural
limits of its context, and then overstepping these limits in
critical ways. Death rates will eventually balance or exceed
reproductive rates, and the population will eventually crash or
achieve some long term equilibrium. A
phenomenon called "endosymbiosis," the encapsulization
of the DNA machinery of one micro-organism by another, and the
appropriation of that machinery, seems to me a fitting
demonstration of a systems-based meta-biotic framework. Virus's
and viroids are similar entities, that, though associated with
disease, demonstrate a kind of meta-biotic complication of
living systems that do not fit normal hierarchical frameworks.
Horizontal transmission of DNA, especially in some forms of soil
bacteria, are another case that clearly defies our received
models of strict vertical and intergenerational transmission of
DNA from parent to offspring. "Endosymbiosis"
becomes the basis for the emergence of Eukarya, more complex
cells, and in turn for multi-cellular organization, which
features functional subordination and specialization of cell
types. A fertilized gamete will carry the blueprints that
include the instructions for the development of a large number
of different specialized cell types performing a host of
integrated functions. The differentiation of so many cell types
from a single precursor resembles the controlled internalized
embodiment of the entire process of taxon evolution of complex
forms from simple parent cells. It is
evident therefore in the first place that all cells are capable
of evolutionary development and speciation through chance
genetic variation of structure. Microorganisms have been
observed to be capable of quite rapid speciation and
evolutionary development, compared to more complex living
systems that are slower to replicate and reproduce. The earliest
known form of cells, presumably some primitive form of Prokarya,
were of minimal possible size and structure, probably less than
five micrometers in diameter and a micron in thickness. This was
perhaps the optimal size for rapid self-replication and
immediate exploitation of whatever growth medium becomes
available. It seems that life seized on the basic principles
involved in this, and capitalized on it as much as possible. It is the
case therefore that in the war against disease, there is a
on-going struggle to develop effective vaccines against new
strains of old strains of bacteria that become immune to
previous remedies through evolutionary adaptation. The
principle function of the cell can be said to provide a suitable
environment for the storage and replication of DNA and the
machinery needed for this storage and replication, as well as
for replication needed for the components of the cell itself. A
cell must therefore be capable of faithfully reproducing its DNA
informational database, and itself. It requires transportable
and usable energy, in chemical form, for carrying out its many
tasks, and it must be capable of somehow capturing and
transporting energy into itself across its membrane. Cellular
reproduction is a normal part of cell growth and its
life-cycle.
Essential components of cells, besides DNA,
are: 1. A cell wall and/or cytoplasmic
membrane
2. Cytoplasm 3. A
nucleus or nucleoid 4. Cellular
Organelles, consisting of ribosomes and/or mitochondrioon,
endoplasmic reticula for the manufacture of proteins and for the
maintenance of cellular tissue structure, function and
equilibrium. The first distinction we
draw is between simple bacteria or prokaryotes, and complex
cells referred to as eukarya or eukaryotes. In general,
prokaryotes are much smaller and simpler than eukaryotes,
averaging between 1 and 5 micrometers (versus about 25
micrometers for eukarya) and about 1 micrometer in depth. They
have a cell wall, but otherwise lack many of the structures
common to eukarya. Prokarya are
simple one-celled organisms capable of fairly rapid
reproduction. They are presumably the first organisms, or the
direct descendants of the first forms of life, to have evolved
on earth. Some have even suggested the possibility that they may
have been carried to earth in a meteorite that crashed in the
best of circumstances (cosmic seeding hypothesis), and from
there began reproducing and evolving. Prokarya are grouped into
bacteria and archaea, distinguished largely by the complex
structures of the cell walls and analytically by their growth
characteristics in various mediums and the ability to stain
under a cover slip of a microscopic slide. Eukarya
evolved from Prokarya, with the suggested mechanism of the
symbiotic ingestion ("endosymbiosis") of one cell by
another to form a more complex structure of organelles like
mitochondria and chloroplasts. Eukarya include algae, fungi,
protozoa and all multi-cellular life forms we know of. Prokarya
in general do not form multi-cellular structures of any form.
They lead an independent life contained within the narrow
confines of their cell wall. Under the right conditions, they
are known to grow rapidly, which growth is defined by the
cellular division and propagation by mitosis at a fairly fast
doubling rate. One possible scenario of
the development of proto-life was that the first forms to emerge
were primitive extremophiles, Archaea, that developed through
chemosynthesis. These eventually differentiated and evolved into
forms that were less marginal and more tolerable of normal
conditions, and that possibly could find a broader range of
energy resources. From these developed what we know of as the
prototypical generalized bacteria. This bacteria became so
successful as an environmental generalist, that the first
adaptive radiation of life was its spread by air, water or any
other medium to virtually the entire earth, to cover the whole
earth in a thin, invisible layer of life. When this prototypical
bacteria encountered extreme conditions, it possibly resumed
characteristics of an extremophile form. One of the main functions
of the cell-membrane is to provide a medium for transport
between the external environment of the cell and the cell's
self-maintaining internal environment. We know from the standard
general system model that such transport mechanisms and mediums
are fundamental to the definition of systems as order creating
and order maintaining processes. The cell membrane, therefore,
with or without the added structural or buffer support of a cell
wall, is a vital component of all cell systems, for they are the
principal transport mechanisms of such systems that maintain
internal equilibrium and stability of the internal environment
across a random and external environment. In
the case of multi-cellular organisms, we must ask what a cell
gives up in terms of its independence as a system, and what it
gains in turn from the specialization of function and
structures. Specialized cells tend to take on definite shapes
and configurations of structure, and they tend to be capable of
performing fairly specialized functions, either in a
chemo-mechanical manner or in terms of the production of special
protein structures or cellular metabolism. What is clear is that
such cells, in become specialized, become dependent upon the
organismic contexts in which they develop--they cannot survive
apart from the super-cellular structures in which they develop. It
is clear that from fairly early on cellular evolution became a
meta-biotic process, with cells respond to and adapting to the
presence and behavior of other cells as a part of their
environment. The most basic form of this kind of interaction was
probably competition of different strains of bacteria for the
same resource substrates. Selection that we can observe at this
level is generally geared to those strains that can effectively
tolerate, adapt to and exploit a different medium. Symbiotic or
complementary relationships between different strains of
bacteria may have developed in time. The
earliest mechanisms of cellular metabolism (catabolism and
anabolism) was presumably some form of chemo-synthesis--the
derivation of usable chemical energy from some form of enzyme
reaction with a chemical substrate. Presumably, one of the first
metabiotic forms of relationship that may have developed between
different species of bacteria may have been that of
predator-prey relations, or the capacity for one strain of
bacteria to attack and consume another form of bacteria for its
energy and material reserves. Photo-synthesis was known to have
evolved from early Eukarya, and presumably one of the first
forms of endosymbiosis may have been in terms of photosynthetic
cloroplasts capable of synthesizing chemical energy from the
energy of the sun. Indirect symbiosis and interdependence also
undoubtedly occurred, by which the action and metabolism of one
organism created the environment suitable for the growth of a
second organism. Presumably, though
there are many kinds of Prokarya we know of today, their basic
structure and function is not so very different than that of
their original precursors, and the diversity of life forms at
this level appears to be far lower overall than the diversity of
more complex multi-cellular organisms. Of all varieties of
prokarya, the forms possibly most similar to the ancestral
"precursor" of life are possibly the archaea though
what we know of these prokarya today is that they have fairly
specialized cellular membranes and walls. |
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| 02/12/05 |
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Balancing Cultural & Natural Ecologies
Human cultural ecology is distinct from the natural ecologies from
which it arose. Human cultural ecology has been extremely successful,
for the most part, in promoting the adaptive and reproductive success of
the human species, and in its diversification to a wide range of niches
in the world. Indeed, its open and constructive capacities has resulted
in the development of entirely new niches and even whole ranges of
niches that did not previously exist before the invention and
construction of culture.
But this success in our shared history has not come without a heavy
price being extracted from our natural environment. Modern Homo sapiens
may have refined the technologies of ecocide, but they were not the
first to invent or utilize such technologies, and we may reach deeply
into our shared heritage to find examples of the mass slaughter of life
and the systematic destruction of entire ecosystems on behalf of
maintaining a growing human system.
This success has been achieved by means of social organization, the
application of technological systems in shaping, controlling and
managing the environment, and in terms of anthropogenic factors like
symbolic language, culture, and mind. We may find counter-examples among
many species of similar forms of adaptation, particularly of social
systems, but these are analogies of parallel evolution of form and
function, and not homologies of shared design features or genetic coda.
It is clear that cultural and natural ecology have
been out of balance, and the former has been advanced largely at the
expense and exploitation of the latter. The sense of imbalance, or
disequilibrium between cultural and natural ecologies is in the long run
bound to have negative consequences for both forms of ecology, to the
extent that cultural ecology is basically bound to and dependent upon
natural ecology, and to the extent that natural ecologies are becoming
increasingly influenced by and under the control of human cultural
ecologies. The long-term consequence of course, as is evident with
Global Warming and other global trends, is the rapid destruction and
disruption of natural ecologies, almost upon every level at which they
occur. These are long-term consequences for which we have known
precedents, and, unfortunately, we do not have to wait very much longer
to bear witness to their dire consequences.
The challenged faced by humankind is to bring back
into balance, upon a new level, both natural and cultural ecologies,
which means primarily the refashioning and reshaping of human cultural
ecologies in a manner that will be less destructive and exploitative of
natural ecologies. First and foremost is the effort to rapidly bring
human population growth to control, even to a level of negative growth.
Secondly, is to curtail and circumscribe the activities of human systems
and communities, in terms that are most relevant to the future
development of natural ecologies.
We are faced with a kind of Easter Island Scenario.
The planet earth is a very large but not unlimited Easter Island. There
is no convenient or suitable way off the island, at least for most
people. We are wholly dependent upon the resources of the island for our
survival and success, and yet by our very success in exploiting the
resources of the island we are jeopardizing our future on that island.
Of course, if we cut down all the trees on the island in order to
transport our giant Moa heads, and we denude the island of all
productive vegetation as a consequence ultimately of too great a human
population, then we run headlong into the problem of the breakdown of
natural ecologies for the sake of maintaining an imbalanced human
ecology. We are then reminded of the Malthusian dilemmas of natural
population increase that outstrips its environmental carrying
capacities.
Altering human adaptive ecology to be more in line
with a natural ecological framework begins with the individual in the
home, but does not end there. Certainly in many systems it is not just
undesirable, but downright socially self-destructive, to abnegate the
drive and symbols of affluence by which modern societies are based and
regulated, even if these patterns towards affluence are directly averse
to the challenge of developing saner and safer human ecologies. I have
learned this by personal experience. It takes organized corporate
institutional structures to effectively implement new designs that
encourage and entail alternative forms of human adaptation. Only by
means of a ground swell, grass-roots movement, a "human tidal
wave" might industry and government be encouraged to adopt
alternative and less exploitative practices. If everyone boycotted those
things known to be the most environmentally destructive, including large
vehicles, etc, then certainly industry would be forced to alter their
designs to suit public demand and taste. But cultivating such a form of
resistance is difficult, especially when vast amounts of capital are
spent just in advertising designed to convince people that they
"need" big vehicles and the stuff that anti-environmental
industry thrives upon.
It becomes in a sense, therefore, a kind of war, made
up of many battles. The first battles are with ourselves in our local
environment--recycling, eating lower on the trophic level, walking
instead of driving, making fewer babies, working for the environment
rather than against it, etc. It extends out to our local and areal
communities--creating awareness, setting examples, participating and
even initiating programs that come to rescue the environment or promote
awareness of the environment. Finally, it extends to regional and
national levels, and ultimately, to international and global levels of
awareness.
We can conclude this overwrought essay by suggesting
that those who are not only a part of the problem but the primary reason
of the problem, cannot be counted upon to change themselves voluntarily,
or to adopt policies that will be in reverse or adverse to their own
established interests that are consonant with the established order of
things in the world. The solution cannot come from those with power, but
only from those who can and must empower themselves. The kind of
revolution of human ecology I'm referring to is ultimately a kind of
pacifist revolution, a concerted effort to deny to those who are in
power and who are a big part of the problem the means of dehumanization
and violence that they use to force their motives and get their way in
the world.
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| 02/05/05 |
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The Case of Bio-genesis of Pre-biotic Systems & Proto-biotics
The object of this digression is not to elaborate a model of
bio-genesis. It is possible that we may never completely understand how
life originated on earth. It is rather to open a forum for inquiry into
the possibilities and "paradigmatic" range of possibilities we
might pose in regard to the development of conjectural hypothesis and
somewhat counter-factual histories of the development of first life,
explained of course from a systems perspective that argues for
stochastic self-organization, or "spontaneous origination" and
not from any form of predetermination or "supernatural
creation". The most noteworthy characteristic of the earth is the
vast abundance of water. Water in some abundance was a precursor to the
development of proto-biotic systems. Water may not have originally been
in the kind of abundance we see today, but it had to be sufficient
enough and probably pure and salty enough, to become the basis of life.
We cannot imagine a sea that is half methanol and half water as the
substrate of life. I think the original ocean had to be a little larger
than a set of tide-pools on a beach or even a chain of crater lakes
where extinct volcanoes once roared. The first question to be answered
then is how was water first created in such abundance on earth, and what
would have been the resulting atmospheric effects of the formation of
large quantities of water on the earth's surface. The pathways that may
have led to this occurrence are not known exactly, and may in fact have
been quite complex by themselves. Photosynthesis in
algae does not appear to the most primitive form of prokaryotic life,
even if it is perhaps the earliest or most primitive form of
"green" life we have. This brings to question the possibility
of life deriving energy from alternative sources than solar light, and
only after first originating then "discovering" light in a
kind of early "photosynthetic revolution." Evidence from
undersea tubules that support rich living formations in the near
complete absence of light suggest that this kind of formation was
possible. Evidence of extremophiles existing in hot-springs or geysers
at temperatures normally beyond that most life-forms can tolerate
suggest the possibility of life forming originally in craters or at the
edges of heat vents in a world presumably more volcanically active than
today. I would think if some form of vulcanism is the most plausible
explanation for the early formation of pre-biotic systems, then this
vulcanism had to carry on in a relatively stable and steady-state manner
in contexts that were not overly disruptive or explosive. We can find
numerous instances of geo-thermal systems on the earth where enough heat
can be produced in the vicinity of stable water sources to create a
sufficient condition for the formation of living systems. Alternative
to heat energy produced by thermal vents, whether submarine or
terrestrial, would be the reliance on some form of chemical
energy--chemical energy that was available in either organic compounds
or inorganic compounds in sufficient quantities to sustain indefinitely
processes of basic replication. We are talking metabolic and catabolic
reactions result in the formation of complex organic chemical molecules,
and in their reformation on a continuous, periodic basis. We can
venture off the edge of probable explanation, and suggest the
possibility of even a cosmic "seeding" hypothesis--meteorites
carrying organic molecules rained down on earth, created craters in
volcanic areas. Rain and water collected in these craters and the
organic molecules began interacting with one another in strange ways. The
first basis of such interaction would be a molecule that is able to
utilize an external source of energy, probably for self-replication. We
can find many examples of simple chemical systems in which molecules are
spontaneously precipitated in concentration when certain threshold
conditions are sufficient. For such a system to work in a
prebiotically sufficiently manner, we would have to assume a semi-closed
kind of system in which energy could be input in regular and probably
steady quantities, and within which a certain kind of complex
equilibrium could be established between a complex molecular form and
its substrate, with the molecular form being able to reproduce itself
from the substrate in a regular manner, at a steady rate, and possibly,
the components of the molecule eventually breaking down and being
recycled into the substrate. New components might be periodically
introduced into such an environment. This early pre-biotic
environment must have been somehow protected from a larger world in some
way that allowed access to energy as well as to the basic building
blocks of the molecules being produced. Not only did such molecules
replicate themselves, but they obviously replicated themselves in
growing numbers. We must imagine at some point the construction or
presence of a barrier or even a "film" or membrane that
isolated the machinery and processes of replication while simultaneously
filtering both the components of replication as well as the energy that
drove such replication. I think something as simple as a soap film, or a
soap bubble, would be sufficient if it permitted transpiration of gases
that might contain energy. Methane gas is a candidate for energy
yielding molecules that might be easily transported across a membrane
from a region of relatively high concentration to a region of low
concentration. A by-product of methane gas combustion would be carbon
dioxide, or alternatively water and oxygen. We can argue for an
early form of a carbon cycle that must have been there in the earliest
system, sans the photosynthesis but with an alternate pathway of
chemo-synthesis that may be catalyzed by thermo-synthesis, or
alternatively, the reverse, thermo-synthesis catalyzed by
chemo-synthetic compounds. In fact, from a systems standpoint, we
should argue for the presence of the basic chemical compounds, and
elements, we find in all life forms today--namely nitrogen, carbon,
oxygen, and hydrogen. The cycles associated with these elements, found
in living systems, and the basic reactions pathways associated with the
organic molecules and compounds associated with these elements, should
be more or less present in some form in the earliest pre-biotic systems.
That water is a universal solvent, and that many solutions occur in
water and many chemical compounds are soluble or partly soluble in
water, seems like a basis for pre-biotic formations. The
complexity of analyzing possible pathways of compounds and energy
relations, especially in terms of bonding of molecules, is too complex
to be explored in this digression. We may in brief speculate that
certain kinds of compounds may have been present in certain forms and
variable concentrations--possibly methane gas, ammonia, water, carbon
dioxide, and probably certain calcium compounds. These would have given
rise to basic lipids, organic molecules, and nitrogen compounds that we
associate with all living tissues and cells. This kind of experiment
in fact resembles in very primitive outline a simple prokaryotic cell,
minus of course the genetic machinery. We must assume that the
pre-biotic molecules were in a sense early genetic sequences of a sort,
that were being replicated on a continuous basis. Enough variability
must have been present in the early stages of this continuous
self-replication that multiple forms or varieties of similar
self-replicating molecules emerged. At this stage, something
else must have happened. The number of sub-processes involved in the
cycles and chains of self-replication gradually became extended at a
number of different points of articulation, and different replicating
"species" of molecule began interacting with one another, and
this interaction eventually must have influenced the context and process
of events in self-replication. It is at this point that I would say we
would step from a "pre-biotic" form to a
"proto-biotic" form of self-replication. Not only would the
basic molecules themselves have to be self-replicated, but the entire
system and even the entire environment become capable of regeneration.
Life at this point quits merely responding to conditions in its
environment, and begins control and creating, in a systems like manner,
conditions of its environment. This is the stage at which we would
expect the emergence of a full-blown prototypical cell that carried and
reproduced not only the essential genetic molecule, but the environment
and machinery for replication as well, including, perhaps most
importantly, the cell wall. I can imagine a prototypical,
generic kind of cytoplasm as somewhat replicating the initial conditions
of the primordial "soup" or broth n which life first formed.
It would be kind of like a small tide-pool at the edge of a steam vent,
constantly full of water, at the bottom of which would collect the right
ingredients for such self-replication to occur spontaneous in an
on-going way--eventually this aggregation would become
"encapsulated" in a shell of sorts, not a hard shell but a
semi-permeable membrane. And eventually, the molecules in this
"large proto-cell" would come to wrap the membrane around
themselves--at the point that they could reproduce not only their own
structure in a consistent manner, but the machinery for maintaining and
producing the membrane as well.
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| 01/28/2005 |
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Natural Self-Organization and the Problem of
Predetermination
All natural systems are self-organizing. They are not
self-organizing in any self-deterministic manner in the sense that their
design is somehow inherent to the parts that compose such systems. Rather, they become
spontaneously organized by themselves when conditions conducive to their
organization, are ripe and available. These conditions are invariably
complex and stochastic in the sense that they are largely based upon the
concatenation of random variables by chance.
Biological systems are the epitome of natural
self-organization, and their finite complexity defies not only
description, but our imagination and sense of credibility. It is no wonder when we deal with the
myriad intricacies encountered in living systems in almost every form of
their expression that we are tempted to believe in some sense of
predetermination of pattern. We may say of course that biological design
is genetically predetermined, as indeed it is. It is in fact by virtue
of non-random genetic determination that life has been able to
perpetuate itself and to recreate itself anew on a continuous basis.
This "self-replication" is something no non-living system has
yet been observed to do. But the question of predetermination comes
before the phenomenon of genetic predetermination--how did life get to
the point of being able to replicate itself in a reliable and consistent
manner?
If the original organization of living systems on
earth was unpredetermined, then it was stochastically achieved within
conditions that were suitable to its spontaneous self-organization. We
can imagine that this was probably only accomplished by much "trial
and error" without implying of course any deliberate intentionality
to the chances processes then occurring. The genetic organization of
life was not achieved by an preordained plan or a-priori sense of
structure. It was achieved through the chance concatenation of factors
that made the organization of genetic codons probable.
If we examine natural evolutionary development of
living forms, we find that it is based upon two principles at least--1st)
chance point mutation in genetic coding sequences that lead to a process of
significant alteration of cellular structure, function and pattern as a
function of RNA transcription; 2nd)
it has been demonstrated that DNA structure and transmission has
undergone several major transformations in the course of evolution,
probably associated with the emergence of new forms of life, and these
kinds of transformations of the transmission process appear to have been
based upon inherent structural variability of the DNA machinery, built
in from the beginning. (From a systems perspective, these principles of
evolutionary dynamics at the genetic level are predictable.)
We can find the evolution of living systems to be a
continuation of natural systems principles of underdetermined
self-organization upon a completely different level, and in fact,
operating upon several levels simultaneously. The inherent multi-level
variability of ecological and evolutionary systems has resulted in the
differentiation of life into a vast number of alternative forms and
designs, and it has resulted in a kind of blind genetic algorithm, a
kind of exploration of alternative possibilities of structure in
systems. We are reluctant to credit any form or sense of
"teleological purpose" to this patterning of Taxon cycles and
evolution of increasingly complex and sophisticated forms of life, but
we can safely invoke systems principles like "equi-finality"
to explain how complex systems can blindly explore a large range of
possibilities of an even larger search-solution landscape and in the
process hit upon remarkable design solutions for life forms to take.
We must somewhat smugly credit ourselves, Homo
sapiens sapiens, as one of those wonderful solutions of this process
of the blind exploration of life's possibilities. I say so not in
sarcasm to our many faults and chronic history of violence and greed,
but in respect and awe of a natural world that can produce such complex
creatures, however imperfect in nature.
I have addressed the question of the
non-predetermination of self-organizing natural systems not because this
has arisen recently as a popular issue in modern American political
culture dealing with this neo-creationist ideology of "Intelligent
Design." Rather, my purpose for addressing the problem of
predetermination in natural systems was to provide some kind of
conceptual platform in a quasi-formal sense for explaining how natural
systems may normally arise, indeed, must arise, from purely chance
conditions which result in the formation of "pre-systems" or
conditions for the organization of systems. This can only be understood
when local conditions permit the augmentation and concentration of
energy as a working gradient against the normal and random process of
entropy, i.e, the non-random organization of natural energy in
"pockets" mediated by some kind of "boundary"
mechanism.
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