Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
The US biologist Stuart Kauffman views the dynamics of “complex systems” as a manifestation of the fundamental force that counteracts the universal drift towards disorder required by the second law of Thermodynamics.
His idea is that Darwin was only half right: systems do evolve under the pressure of natural selection, but their quest for order is helped by a property of our universe, the property that "complex" systems just tend to organize themselves. Darwin's story is about the power of chance: by chance life developed and then evolved. Kauffman's story is about destiny: life is the almost inevitable result of a process inherent in nature.
Kauffman's starting point was that cells behave like mathematical networks.
In the early 1960s the French biologist Jacques Monod and others discovered gene regulation: genes are assembled not in a long string of instructions but in "genetic circuits". Within the cell, there are regulatory genes whose job is to turn on or off other genes. Therefore genes are not simply instructions to be carried out one after the other. Genes realize a complex network of messages. A regulatory gene may trigger another regulatory gene that may trigger another gene…etc. Each gene is typically controlled by two to ten other genes. Turning on just one gene may trigger an avalanche of effects.
The genetic program is not a sequence of instructions but rather a regulatory network that behaves like a self-organizing system.
By using a computer simulation of a cell-like network, Kauffman proved that, in any organism, the number of cell types must be approximately the square root of the number of genes.
He basically started where Langton ended. His “candidate principle” states that organisms change their interactions in such a way to reach the boundary between order and chaos.
For example, the Danish physicist Per Bak ("Self-organized criticality”, 1987) studied a pile of sand, whose collapse under the weight of a new randomly placed grain is unpredictable. However, when it happens, the pile reorganizes itself. While it is impossible to predict if a particular grain will cause an avalanche, the size of these avalanches is distributed according to a "power law". No external force is shaping the pile of sand: it is the pile of sand that organizes itself.
Further examples include any ecosystem (in which organisms live at the border between extinction and overpopulation), the price of a product (which is defined by supply and demand at the border of where nobody wants to buy it and where everybody wants to buy it). Evolution proceeds towards the edge of chaos. Systems on the boundary between order and chaos have the flexibility to adapt rapidly and successfully.
Natural selection and self-organization complement each other: they create complex systems poised at the edge between order and chaos, which are fit to evolve in a complex environment. At all levels of organization, whether of living organisms or ecosystems, the target of selection is a type of adaptive system at the edge between chaos and order.
In 1932 the US biologist Sewall Wright had introduced the concept of "fitness landscapes". Fitness is the replication rate of a genotype. A fitness landscape is a distribution of fitness values over the space of genotypes. In other words, the fitness landscape describes all possible genotypes, their degree of similarity and their fitness values. Fitness is related to height in the landscape. Genotypes that are very similar are close to each other in the landscape.
Evolution is the traversing of a fitness landscape. Peaks represent optimal fitness. Populations wander through the landscape, driven by mutation, selection and drift, in their search for peaks. Kauffman showed that the best strategy for reaching the peaks occurs at the phase transition between order and disorder, or, again, at the edge of chaos. The same model applies to other biological phenomena and even nonbiological phenomena, and may therefore represent a universal law of nature.
Adaptive evolution can be represented as a local “hill-climbing search” that converges via fitter mutants toward some local or global optimum. Adaptive evolution occurs on rugged (multipeaked) fitness landscapes. The very structure of these landscapes implies that “radiation” and “stasis” are inherent features of adaptation. The Cambrian explosion and the Permian extinction (famous paradoxes of the fossil record) may be the natural consequences of inherent properties of rugged landscapes.
Kauffman also noted how complex (nonlinear dynamic) systems which interact with the external world are bound to “classify” and “know” their world through their attractors.
Kauffman's view of life can be summarized as follows: autocatalytic networks (networks that feed themselves) arise spontaneously; natural selection brings them to the edge of chaos; a genetic regulatory mechanism accounts for metabolism and growth; attractors lay the foundations for cognition.
The main theme of Kauffman's research is the ubiquitous trend towards self-organization. This trend causes the appearance of "emergent properties" in complex systems. One such property is life. The requirements for order to emerge are far easier than traditionally assumed.
There is order for free.
Far from equilibrium, systems organize themselves. The way they organize themselves is such that it creates systems at higher levels, which in turn tend to organize themselves. Atoms organize in molecules that organize in autocatalytic sets that organize in living organisms that organize in ecosystems.
The whole universe may be driven by a principle similar to autocatalysis. The universe may be nothing but a hierarchy of autocatalytic sets.
Of course, one possible objection to the whole theory of “self-organizing” systems is that no system truly “self-organizes”: they all depend on external energy. Thus one could claim that it is the external energy that organizes them. Self-organizing systems, strictly speaking, do not exist. Only the universe as a whole can be said to be truly self-organizing.
Chaos as the Creator
Anorther corollary to this vision of multi-layered self-organization is about the role played by chaos. Gregory Bateson, Francisco Varela, Chris Langton and Stuart Kauffman assign a creative role to chaos. A living organism is a self-organizing sysetm, a system that tries to maintain order inside. Outside there is a chaotic world, and that is the reason why the self-organization is a continuous, endless process. At that same time it is that chaotic "outside" that fosters creativity, growth and evolution. Too much "chaos" might kill the living organism, but, whenever the organism if capable of responding to chaos, the result is actually an increase in complexity and "intelligence".
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