So I'm a big fan of the HBO series, West World. It's a remake of the 70s movie in a series format. The next episode is titled, "The Bicameral Mind".
The Bicameral Mind is a hypothesis of how consciousness developed. The hypothesis was put fort by Julian Jaynes in his 1976 book, "The Origin of Consciousness in the Breakdown of the Bicameral Mind"
In a nutshell, the hypothesis states that consciousness, the ability of self-awareness, only evolved around 3,000 years ago. Prior to this time, human were non-conscious, having little to no self-awareness, something kin to an android or robot, only carrying out programmed behavior.
The word "bicameral" means "two-chambered". This is a reference to the belief that these non-conscious humans had their minds divided into roughly two hemispheres. The right hemisphere, call the god portion, and the left hemisphere. The god portion communicated to the left hemisphere via auditory hallucinations that humans interpreted as the voices of the gods or deceased ancestors. The left hemisphere simply obeyed the voices that told them what to do without question.
In a nutshell, people before 3,000 years ago did not understand that these voices where "theirs". They attributed thought and these auditory hallucinations to an outside, supernatural force, i.e. "the gods". It was this that spurned the development of religion where these "voices" appeared to be vastly superior to humans. Civilization was constructed around this framework, with a king or ruler that dictated behavior and subjects that did as they were told, reflecting the bicameral mind.
The important thing to comprehend about this is also the hardest thing to comprehend. How can a conscious being understand what it's like to be non-conscious?
These people, though outwardly looking human, even possessing human behavior, were not human mentally. There was nothing going on inside them. There was no introspection. They had no concept of "I"-ness. They were literally like robots. They merely responded to stimuli. The light was on but nobody's home.
There is considerable evidence that this is the case because much of the stories and writings of ancient man do survive. In these writings, which include much of the old portions of the Old Testament, it's clear that people were just like this. They constantly heard the gods (or God). They spoke nothing about any internal thoughts or feelings. It was only reaction to outward stimuli. It's very odd.
The one literary work that is picked as the best example of this is Homer's Odyssey. In it Odysseus hallucinates the voices of the gods telling him what to do left and right. His men, and every other character, are just robots who then obey his commands. They have no internal life. They are simple automatons.
Sometime around 3,000 years ago things began to change in human society. New stresses and circumstance helped for the evolution of "I"-ness, which is the birth of consciousness. Now mankind was fully human. The voices of the gods fell silent, only rearing their heads in that state between sleeping and wakefulness as well as various mental illnesses.
This is a remarkable, mind-blowing hypothesis. It's not without it's kinks but it's a fascinating subject to study. If this turns out to be true then I'm convinced there are people today who are non-conscious. I've met numerous people who claim that God talks to them in an actual voice and not just a feeling. I've met many more people that seem to be incapable of introspection. Can you imagine if the world slipped back into this non-conscious state again? One would be the last human on the planet even though the world would be full of people. Since we don't truly understand why consciousness evolved it may actually be possible that our species might once again slip back into non-consciousness and return to the bicameral mind.
Also, if this fascinates you like it does me, check out the link below. This truly frightens me!