Julian Jaynes developed a hypothesis called
Bicameralism where human mind, before being conscious, was then divided into two parts: one in command, called God (taking its foundations in the right hemisphere), and the other part obeyed, housed in the left hemisphere, called Man. This bipartition was the modus operandi of the bicameral mind. In the bicameral mind, volition/will, development and initiative organized themselves without the help of awareness in the right hemisphere and were then sent to the person in the language she/he knows, in the left hemisphere, sometimes accompanied by the appearance of a friend, an authority figure or a god. The person then obeyed the voice because she/he didn't know what to do alone. In all her/his actions, the Man was with a response such as ours (nowadays), but the decision during a moment of stress was performed using a voice that collected the admonitory wisdom accumulated during his life . These voices rumbled, comforted, commanded or announced what would happen: they were also producing eventually visual hallucination, a figure.
The hypothesis of Jaynes is that the bicameral mind was the form of social control that allowed humanity to move from small groups of hunter-gatherers to large farming communities. The bicameral mind, controlled by the gods, would have developed as the final step in the evolution of language, and it is in this development that lies the source of civilization. Auditory hallucinations, developing as a side effect of language comprehension. It was no longer necessary for a chief/king to rely on repeated meetings with each person to exercise his domination. The hallucinations were particularly supported by the statues and funerary art, specific to reactivate the voices (the hypnotic state is encouraged by the predominance of eyes, staring with authority).
The profound and irreversible changes scoring the second millennium BC -the frequency of wars, disasters. In the space of a day, entire populations were forced into exodus, and the appearance of cruel king such as Tiglath-Pileser I in Assyria who massacred thousands of harmless villagers- gave birth to a loosening of the association between God and Man, divine voices could no longer meet the increased stress of the Man and couldn't allow him to avoid more death.
This chaos was durable: it was prolonged in Greece under the name of Dorian invasions. That voice was compensated by the importance given to writing. As for the observation of the difference in others (another language, another people, another god), it may be that it is the source of psychic space.
When the voice of the gods is silent, prayer appears to bring it back. The first king kneeling is the Assyrian king Tukulti-Ninurta I in 1230 BC.
The theme of World Religions appears for the first time : why the gods have they abandoned us? They must have been offended. Our troubles are punishment for our sins. We apologize to the gods. The chiefs/kings who have no gods are restless and uncertain, their authority is questionable, and they must turn to the omens and divination. One must ask the gods to speak again. Angels and demons appear as intermediate creatures, or messengers, and the heavens/skies as dwelling place of the gods.
The history of mankind after the disappearance of voices is intertwined with the search for the lost authorization. The gods no longer speak, but everything is organized by them: they record our births, define us, marry us, bury us, receive our confessions; our laws are based on values that without their divine counterpart, would be empty and unenforceable. The overwhelming importance of religion in the history of mankind is the trace: the man doesn't give up his fascination and nostalgia for a mystery with powers beyond the capacity of the left hemisphere.
The search continues. The search for a lost innocence. The search for a moment of authentic humanity before the descent into the irreversible line of civilization.