The notion of evolution, generally speaking, describes the progressive transition of simple systems towards more elaborate ones, but more specifically this term is most often reserved for the evolution of the universe.
Transcending Lamarck and Darwin, who described only parts of the natural evolution, the French Jesuit and paleontologist Pierre Teilhard de Chardin (1881-1955), developed a model (The Phenomenon of Man, manuscript 1938 English translation New York: Harper and Row, 1959) describing the cosmic evolution, starting with the Big Bang (the Alpha Point), and ending with the Omega Point. The humanistic and agnostic biologist and philosopher Julian Huxley (1887-1975) joined his views (Essays of a humanist, New York: Harper & Row, 1964). His theory doesn't yet seem to be surpassed. He was one of the first scientists, with Whitehead, to use the integrative method as a scientific tool to describe levels of reality beyond the reach of the experimental physical scientific method.
The fundamental mechanisms
Teilhard stated that the evolution of the Universe is characterized by his law of complexity and consciousness (or, to use a term of Paulo Freire (1970): conscientization), by which he described two fundamental tendencies: (1) an increasing complexification and (2) an increasing consciousness.
The development of natural systems towards more complex systems and organisms progresses along two movements:
- a complexification within the own level, i.e. more complex "variations" with the same building blocks; e.g. atoms becoming more complex from hydrogen (1 proton) towards uranium (92 atoms)
- a complexification by jumping to a higher level, i.e. using elements of the former level as building blocks, e.g. molecules composed by atoms, society composed by individuals.
The second movement starts when the first reaches its end, as if nature considered more trials within the actual level as non-productive.
This fundamental process generated, up to now, nine levels of complexification, as far as scientific knowledge reaches. It's nice to remember that Teilhard "forgot" stages 1, 2 and 6, not yet discovered at that moment, and proposed a 6-layer model. But it's impressive to consider that those three "new" levels smoothly shoved into the existing model, rather confirming than refuting it.
The subsequent levels in the evolution of the Universe
Those 9 layers are:
- the (super)strings.
- the elementary particles: quarks, the photon and the electron; they are complexes of strings.
- the atomic particles, including protons, neutrons and baryons; they are complexes of quarks.
- the atoms, ranging from Hydrogen to Uranium (everything beyond Uranium is artificial, and very short-living); they are complexes of elementary particles.
- the molecules, including the anorganic (e.g. water), evolving to the organic (with the amino-acids); they are complexes of atoms
- the eobionts or protoplasmic organisms, ranging from poorly organized proteins to complex organelles, i.e. cell constituents that existed autonomously, outside the cell, at a certain point in evolution, and also viruses, but today are only found inside cells; they are complexes of proteins and other organic and anorganic molecules.
- the protozoa, i.e. the individual cell evolving from primitive organisms to organized complexes of organelles
- the metazoa, i.e. the animals (and a side branch of plants), ultimately evolving to mammalian, hominids and man; they are complexes of cells.
- the socialization, i.e. a symbiosis of humans, a mental noosphere, organizing not only society, but also matter on a planetary and universal scale, and probably interacting and cooperating one day with intelligent beings from other inhabited planets.
These 9 levels can be grouped into 3 kind of systems:
- the Lithosphere (levels 1 to 5): consisting of "dead" matter, whose states and functioning is completely regulated by external and structural influences
- the Biosphere (levels 6 to 8): consisting of "living" structures, whose activities and development is regulated by a genetic program (DNA, reflexes and instincts)
- the Noosphere (level 9): consisting of the actual human society, whose activities and development is regulated by developing concepts of reality
This rather misty concept of Teilhard is not to be reduced to the Christian soul, but could rather be interpreted as a software (the mind), residing in a suitable hardware (the brain). It is a regulating system, that enables the composition of complex organisms, and the interaction of these organisms with a expanding part of the environment.
- In the lithosphere there is no separate knowledge system. One could say that the structure of the elements from level 1 to 5 reflects somehow an increasing "clever" application of the elementary laws of physics, enabling the development gradually more complex natural systems (from strings to molecules)
- In the biosphere the "experience" enabling the development of gradually more complex systems is stored in genetic programs, from simple DNA to chromosomes, that regulate the structural development, and later the installation of reflexes and instincts. During level 8 (the animals) a memory and learning ability is developed, completing the inborn "wisdom" by individually experiences for successfully achieving one's goals.
- In the noosphere (humanity) the frontal brain enables abstraction, logical thinking and complete consciousness, by the gradual development of an internal image of external reality, enriched with abstractions and creative thinking.
Some arguments for this hypothesis
Arguments that sustain the complexity-consciousness hypothesis include:
- The extreme simplicity of the system, never surpassed to date by a more general or more simple explanation. It's a kind of natural systems theory.
- All existing scientific observations and theories are integrated in this hypothesis
- The fact that at each level, organisms are exclusively using building blocks from the former level, and nearly never from any more primitive level. E.g. in a metazoon (level 8), everything, including the rigid bones and the shield of the turtle, and even blood, is composed of living cells (level 7). Molecules (level 5) are only composed of atoms (level 4). Only man (starting with the primates) invents technology, i.e. makes tools composed of elements of lower levels
- The apparent extinction of evolution at a certain point of complexity within the actual level. It is even extremely difficult if not impossible to transgress these natural limits, e.g. the impossibility to synthesize really stable atoms beyond uranium, the most complex "natural" atom.
- It is striking that the duration of each level shortens with the same factor, i.e. 0.618 (the Golden Section), with the exception of the first two or three levels, disappearing in the mist of relativistic speeds. This temporal regularity suggests a fundamental process.
 Teilhard de Chardin, Pierre: 'The Phenomenon of Man' (Fountain Books, 1977), p. 86.
 Freire, P.: 'Pedagogy of the Oppressed' (New York: Herder & Herder, 1970).
Thank you, Brian Cowan.