Evolutionary and neurobiological bases of theism

According to evolutionary psychology, all human behaviours are a product of internal mechanisms in conjunction with inputs that cause activation of those mechanisms: no mechanism, no behaviour; no input, no behaviour. From an ethological point of view, the most important religious behaviours consist in the gathering of humans who perform demonstrations of submission toward supernatural individuals endowed with an immense power. About the genesis of the ideas of such beings, Freud felt that they could be the projection result of the “primordial horde’s father” in a super-human world. Subsequently Morris has proposed that divine beings risult from the projection of the figure of the dominant male of a “Single Male” breeding group. However, inferring social behaviour from the sexual dimorphism noticed in fossils, most scholars think that in ancient groups of Hominini endowed with low sexual dimorphism (as from Homo habilis or Homo erectus), there was not any individual, i. e. dominant male of a SM social group, that could act as realistic example of a “Immense Powerful Being”. How, among humans with a low male-male competition, could a projection in a super- human world of a being that should have to be associated with a high male-male competition social system have happened? A possible answer is that the human brain preserved (and still preserves) hierarchy forming structures. MacLean described primate’s brain as formed by three principal philogenetic structures that have been integrated during evolution. He called these basic types Reptilian (R – complex), Old mammalian (Limbic System), and Neomammalian (as Neocortex) brains. The counterpart of the Reptilian brain in Mammals is fundamental for genetically constituted forms of behavior as hunting, mating, and forming social hierarchies. The Limbic System may be seen as a regulator (mostly inhibitory) of the R–complex, while the Neomammalian brain is the main seat of cognitive and conscious capabilities. Following d’Aquili and Newberg, we have also considered behavioral, emotive and cognitive operators as specific functions performed by brain’s regions. According to a model integrating MacLean’s and d’Aquili and Newberg’s conceptions, the neocortical concept of an Immense powerful being can be only created after a proposal emerging from the R–complex. Consequently we can deduce that at some time in human evolution such a nervous structure has been set free from the inhibitory action of the Limbic System as a consequence of a strong stimulus. We may presume that this “input” consisted in the awareness of death. Homo sapiens is conscious of being mortal, but he does not recognize this fact as a natural datum. Instead he feels death as violence; we may presume that in this way death could have been considered by early humans. As the neocortex seeks to determine agents who cause phenomena, early humans tried to find the cause of death, but failed in this. Because of this shock, the Limbic System activity on R-complex would have had a variation that caused the activation of hierarchic R-complex structures and that led the Neocortical structures to accept the idea that a “Powerful, but unseen, Being” was the agent of death. After this, the neocortical association areas, in relations to environment, developed various systems of religion.