[Paleopsych] SW: Complexity and Causality
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Theoretical Physics: Complexity and Causality
http://scienceweek.com/2005/sw050819-6.htm
The following points are made by George F. Ellis (Nature 2005
435:743):
1) The atomic theory of matter and the periodic table of elements
allow us to understand the physical nature of material objects,
including living beings. Quantum theory illuminates the physical basis
of the periodic table and the nature of chemical bonding. Molecular
biology shows how complex molecules underlie the development and
functioning of living organisms. And neurophysics reveals the
functioning of the brain.
2) In the hierarchy of complexity, each level links to the one above:
chemistry links to biochemistry, to cell biology, physiology,
psychology, to sociology, economics, and politics. Particle physics is
the foundational subject underlying -- and so in some sense explaining
-- all the others. In a reductionist world view, physics is all there
is. The cartesian picture of man as a machine seems to be vindicated.
3) But this view omits important aspects of the world that physics has
yet to come to terms with. Our environment is dominated by objects
that embody the outcomes of intentional design (buildings, books,
computers, teaspoons). Today's physics has nothing to say about the
intentionality that has resulted in the existence of such objects,
even though this intentionality is clearly causally effective.
4) A simple statement of fact: there is no physics theory that
explains the nature of, or even the existence of, football matches,
teapots, or jumbo-jet aircraft. The human mind is physically based,
but there is no hope whatever of predicting the behavior it controls
from the underlying physical laws. Even if we had a satisfactory
fundamental physics "theory of everything", this situation would
remain unchanged: physics would still fail to explain the outcomes of
human purpose, and so would provide an incomplete description of the
real world around us.
5) Can we nevertheless claim that the underlying physics uniquely
causally determines what happens, even if we cannot predict the
outcome? To examine whether we can, contemplate what is required for
this claim to be true within its proper cosmic context. The
implication is that the particles existing when the cosmic background
radiation was decoupling from matter, in the early Universe, were
placed precisely so as to make it inevitable that 14 billion years
later, human beings would exist, Charles Townes would conceive of the
laser, and Edward Witten would develop string theory. Is it plausible
that quantum fluctuations in the inflationary era in the very early
Universe -- the source of the perturbations at the time of decoupling
-- implied the future inevitability of the Mona Lisa and Einstein's
theory of relativity? Those fluctuations are supposed to have been
random, which by definition means without purpose or meaning.[1,2]
References:
1. Ellis, G. F. R. Phys. Today (in the press).
2. Bishop, R. C. Phil. Sci. (in the press).
Nature http://www.nature.com/nature
--------------------------------
Related Material:
THEORETICAL BIOLOGY: ON SCALE AND COMPLEXITY
The following points are made by Neil D. Theise (Nature 2005
435:1165):
1) Complexity theory, which describes emergent self-organization of
complex adaptive systems, has gained a prominent position in many
sciences. One powerful aspect of emergent self-organization is that
scale matters. What appears to be a dynamic, ever changing
organizational panoply at the scale of the interacting agents that
comprise it, looks to be a single, functional entity from a higher
scale. Ant colonies are a good example: from afar, the colony appears
to be a solid, shifting, dark mass against the earth. But up close,
one can discern individual ants and describe the colony as the
emergent self-organization of these scurrying individuals. Moving in
still closer, the individual ants dissolve into myriad cells.
2) Cells fulfill all the criteria necessary to be considered agents
within a complex system: they exist in great numbers; their
interactions involve homeostatic, negative feedback loops; and they
respond to local environmental cues with limited stochasticity
("quenched disorder"). Like any group of interacting individuals
fulfilling these criteria, they self-organize without external
planning. What emerges is the structure and function of our tissues,
organs and bodies.
3) This view is in keeping with cell doctrine -- the fundamental
paradigm of modern biology and medicine whereby cells are the
fundamental building blocks of all living organisms. Before cell
doctrine emerged, other possibilities were explored. The ancient
Greeks debated whether the body's substance was an endlessly divisible
fluid or a sum of ultimately indivisible subunits. But when the
microscopes of Theodor Schwann (1810-1882) and Matthias Schleiden
(1804-1881) revealed cell membranes, the debate was settled. The
body's substance is not a fluid, but an indivisible box-like cell: the
magnificently successful cell doctrine was born.
4) But a complexity analysis presses for consideration of a level of
observation at a lower scale. At the nanoscale, one might suggest that
cells are not discreet objects; rather, they are dynamically shifting,
adaptive systems of uncountable biomolecules. Do biomolecules fulfill
the necessary criteria for agents forming complex systems? They
obviously exist in sufficient quantities to generate emergent
phenomena; they interact only on the local level, without monitoring
the whole system; and many homeostatic feedback loops govern these
local interactions. But do their interactions display quenched
disorder; that is, are they somewhere between being completely random
and rigidly determined? Analyses of individual interacting molecules
and the recognition that at the nanoscale, quantum effects may have a
measurable impact, suggest that the answer is yes.[1-3]
References:
1. Theise N. D. & d'Inverno, M. Blood Cells Mol. Dis. 32, 17-20 (2004)
2. Theise N. D. & Krause D. S. Leukemia 16, 542-548 (2002)
3. Kurakin A. Dev. Genes Evol. 215, 46-52 (2005)
Nature http://www.nature.com/nature
--------------------------------
Related Material:
PHYSICS AND COMPLEXITY
The following points are made by Gregoire Nicolis (citation below):
1) For the vast majority of scientists physics is a marvelous
algorithm explaining natural phenomena in terms of the building blocks
of the universe and their interactions. Planetary motion; the
structure of genetic material, of molecules, atoms or nuclei; the
diffraction pattern of a crystalline body; superconductivity; the
explanation of the compressibility, elasticity, surface tension or
thermal conductivity of a material, are only a few among the
innumerable examples illustrating the immense success of this view,
which presided over the most impressive breakthroughs that have so far
marked the development of modern science since Newton.
2) Implicit in the classical view, according to which physical
phenomena are reducible to a few fundamental interactions, is the idea
that under well-defined conditions a system governed by a given set of
laws will follow a unique course, and that a slight change in the
causes will likewise produce a slight change in the effects. But,
since the 1960s, an increasing amount of experimental data challenging
this idea has become available, and this imposes a new attitude
concerning the description of nature. Such ordinary systems as a layer
of fluid or a mixture of chemical products can generate, under
appropriate conditions, a multitude of self-organization phenomena on
a macroscopic scale -- a scale orders of magnitude larger than the
range of fundamental interactions -- in the form of spatial patterns
or temporal rhythms.
3) States of matter capable of evolving (states for which order,
complexity, regulation, information and other concepts usually absent
from the vocabulary of the physicist become the natural mode of
description) are, all of a sudden, emerging in the laboratory. These
states suggest that the gap between "simple" and "complex", and
between "disorder" and "order", is much narrower than previously
thought. They also provide the natural archetypes for understanding a
large body of phenomena in branches which traditionally were outside
the realm of physics, such as turbulence, the circulation of the
atmosphere and the oceans, plate tectonics, glaciations, and other
forces that shape our natural environment: or, even, the emergence of
replicating systems capable of storing and generating information,
embryonic development, the electrical activity of brain, or the
behavior of populations in an ecosystem or in an economic environment.
Adapted from: Gregoire Nicolis: in: Paul Davies (ed.): The New
Physics. Cambridge University Press 1989, p.316
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