The contemporary astrophysicist today deals with questions that bear on the area known to traditional philosophy as “metaphysics.” Consequently, it is tempting to cross the threshold. One can allow oneself to be tempted by the idea that science is in a position to provide solutions to ancient and venerable metaphysical quests. One can even imagine, according to the wish expressed two thousand years ago by Epicurus, that it can calm our “metaphysical anxieties.”

The universe, of which our domicile the planet Earth forms but a minuscule part, has an architecture that changes and has been changing in time. In other words, it has a history of evolution. Lack of experimental evidence denies us the knowledge of what the universe was like “at the time of its origin,” as discussed by Hubert Reeves in the preceding chapter. Neither do we know much about its geometry, simply because our observatories are concentrated, for all practical purposes, vanishingly close to a single point in an immensity whose size can only be measured by the billions of years required by light to go from one extremity to another!

The earth, the abode of the only form of intelligent life in the universe of which we are aware, is a minor member of a system of nine planets, 40 or so moons and about 100 billion asteroids orbiting around the Sun, an average-size member of the 100-billion-star community making up our galaxy, the Milky Way. It is the third planet to the Sun, which it orbits, following an almost circular elliptical path maintaining an average distance of 1.5×108 km, with the longest and the shortest radii now being 1.53×108 km and 1.47×10 km respectively (Fig. 1). This orbit is subject to changes in its “eccentricity” (i.e., in how much it deviates from a circle) with periods of 105 and 4×10 years5 years (Fig. 2A). In addition, the elliptical orbit itself slowly rotates as shown in Fig. 2B, in what we call the precession.

The term “origin” is associated with a beginning, a debut, a birth. Expressions such as “the origin of life” or “the origin of man” suggest unique moments linked to remarkable phenomena. In the following pages, we will attempt to show that, since its birth, the universe has been undergoing a process of self-organization. The appearance of life on Earth represents one of the stages in this process.

Palaeontology is an historical science comparable to prehistory, archeology, and history, in that it deals with living beings from past times. The documents needed to write the history of life are the remains of organisms contained in geological deposits from the last four billion years. They are called “fossils.”

In order to tell the story of Man and understand our emergence better, we can readily follow on from Heinz Tobien, though we do not need to go back so far in time - just a few million years.

Clearly, our fundamental origin is animal. Thus it is easy to understand that in the great genealogy (known as phylogeny), there was one vital (geological) moment when our line was forever detached from the animal “kingdom.” The evidence of palaeontology, like that of molecular biology, today locates this point - which is, by definition, the very point of origin of our family, the hominids - in Eastern Africa around 8 million years ago. In order to state this, palaeontology rests on two sets of results. All the most ancient hominids, without exception, are East African, and the oldest of all goes back more than 7 million years. Through the study of various characteristics of the cells of contemporary primates, having arranged them in an order of increasing complexity and having hypothesized that this contemporary complexity may be a reflection of that which developed through time, molecular biology has, on the basis of palaeontological dating, calibrated this transformation and its different stages and constructed what is called a molecular clock. In this way, it has arrived at two conclusions. The primates closest to Man are by far the great African apes (chimpanzees, gorillas), and the “distance” that separates us - in other words the degree of difference that exists between them and us - situates the divergence of our two branches at just over 7 million years.

If we consider human thought as the, so far, ultimate, if not supreme, stage in the evolution of life on Earth, we must also try to understand the evolutionary conditions that allowed it to emerge, and that leads us to look again at living organization.

Whatever the origins of life (cf. the text of Jacques Reisse, p. 53), it is clear that the oldest living organization, that of a protobacteria, is extremely complex in its functional and complementary association of extremely diverse macro-molecules, and that this complexity includes in particular: a) the organization of exchanges with an environment from which it draws both matter-energy and organization ; b) a permanent process of self-reorganization through the replacing of molecules that have deteriorated and through the production of new ones; c) the organization of the self-reproduction of the creature through division. An organization of this kind includes a quasi-informational dimension (the hereditary message inscribed in the genes and the capacity to extract information from the environment), a quasi-computational dimension (the processing of data, via indices or quasi-signs from the interior and exterior), and a communicational dimension (internal RNA-protein communication and external communication with its congeners). In short, from the beginning, a living being is the product/producer of a self-eco-organization the nature of which is at the same time computational, informational, and communicational. In other words, within every living organization, there is a cognitive dimension, but this cognitive dimension is undifferentiated within it.