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, 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 shortliving); 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, hominoids 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 compostion 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.
Some other characteristics of Evolution
- At every level nature encounters a natural limit, (Teilhard called these boundaries critical points) apparently marking the exhaustion of evolutionary possibilities (although evolution continues at a higher level, adding just one degree of complexity).
- In every domain, when anything exceeds a certain measurement, it suddenly changes its aspect, condition or nature. The curve doubles back, the surface contracts to a point, the solid disintegrates, the liquid boils, the germ cell divides, intuition suddenly bursts on the piled up facts... Critical points have been reached, rungs on the ladder, involving a change of state -- jumps of all sorts in the course of development. 
- Moreover, when science and technology try to transgress this point, it up to now never succeeded, to th egreat frutsration of scientists. The most striking example of this in the development of more compelx atoms than Uranium (92), nature's ending point. No cyclotron up to date succeeded in the breeding of a new stable element: only extremely short living times were encountered so far. Scientists already feel gratified when they encounter a "stability" close to 1 second...
- For the same reason "Teilhardians" fear that transgressing the ending point of Man (stag 8) will prove difficult or perhaps impossible, to the great frustration of genetic scientists.
- During evolution, the "dominant" system organizing the superior one, moves form the left end of the range (simple building blocks) to the right (the most evolved samples). E.g. at the molcular level, the most important and central atomes are simple elements such as hydrogen, oxygen and carbon. At higher biological levels the most elaborated structures become the building blocks: well developed cells for metazoa, and man for the socialization. This shift arises from the organizing principle: in dead matter structural versatility is of the essence, so that simple, versatile elements are favoured. On the contrary, with more complex organisms, complex intelligence is preferable, so that for the "last" level of evolution, socialization and the noosphere, the most elaborated metazoon, homo sapiens, offers most possibilities.
- There exist some impressive analogies between level 8 (the metazoa) and level 9 (socialization): as blood vessels transport products and cells from the point of production to the point of application, rivers and streets develop in society. As the nervous system transports information in both senses between decision making and executive centres, electrical and other communition devices connect people. The description of society as a planetary body of humans (and other beings and objects) is more than poetic.
Nevertheless there are some striking differences, due to the fact that. with homo, evolution changes its tactics for a versatile interaction with the environment. We observe a disconnection between the organizing and the performing device, the latter becoming external to the person. Up to the sub-primate level, progress in evolutionary effectiveness consisted in anatomic adaptation. Animals that run fast are physically conceived to run fast, most often at the expense of other abilities, say climbing, flying and swimming. In biophase, we observe a universal differentiation and specialization. With man, both functions are disconnected:
We can observe the same trend in nowadays' computers: they are becoming "mutipurpose", taking the "intelligent" part of the job for themselves, and reducing peripheral devices as printers, scanners, musical instruments and speakers to their most essential performing aspects.
This departicularization of the intelligent element, i.e. man, not only leeds to a even more far-reaching organization and transformation, through technology, of the non-human world, but frees humans. For the first time in history, an organism is able to take part in complexigfication without losing its individuality. This means that futuristic theories which imply the loss of an individual's ability to move or to think independently, and with a total, global application filed: human thinking and consciousness intends to cover all aspects of intelligible reality, and will, at least for the final decision making, not be surpassed by computers. We'll discuss this interesting topic in another page.
This is bad news for geneticians, who are dreaming to perfect human nature, reduce his aggressiveness etc. by genetic manipulation. In fact, biological evolution came to an end, and did so already a long time ago. Of course, genetic manipulation will allow us to make some useful corrections and repairs in diseases. It is, from a Teilhardian perspective, unlikely that psychological and technological evolution will be stopped one day, and that nature should return to a more primitive strategy.
 Teilhard de Chardin, Pierre: 'The Phenomenon of Man' (Fountain Books, 1977), p. 86.
Thank you, Brian Cowan.