"At one time human nature was split in two, an executive part called a god, and a follower part called a man.
Neither part was Consciously aware."[1]
According to Jaynes, ancient people in the bicameral state would function in a manner similar to that of a modern-day schizophrenic. Rather than making conscious evaluations in novel or unexpected situations, the person would hallucinate a voice or "god" giving admonitory advice or commands, and obey these voices without question. Others have argued that this state of mind is recreated in members of cults.[2]
In his 1976 work The Origin of Consciousness in the Breakdown of the Bicameral Mind, Julian Jaynes proposed that human brains existed in a bicameral state until as recently as 3000 years ago. Jaynes builds a case for this theory by citing evidence from many diverse sources including historical literature. He took an interdisciplinary approach, drawing data from many different fields.[3]
Jaynes asserts that until roughly the times written about in Homer's Iliad, humans did not generally have the self-awareness characteristic of consciousness as most people experience it today. Rather, Jaynes argued that the bicameral individual was guided by mental commands believed to be issued by external "gods"—the commands which were so often recorded in ancient myths, legends and historical accounts; these commands were however emanating from individuals' own minds. This is exemplified not only in the commands given to characters in ancient epics but also the very muses of Greek mythology which "sang" the poems: Jaynes argues that while later interpretations see the muses as a simple personification of creative inspiration, the ancients literally heard muses as the direct source of their music and poetry.
Jaynes inferred that these "voices" came from the right brain counterparts of the left brain language centres—specifically, the counterparts to Wernicke's area and Broca's area. These regions are somewhat dormant in the right brains of most modern humans, but Jaynes noted that some studies show that auditory hallucinations cause increased activity in these areas of the brain.[3]
For example, he asserts that, in The Iliad and sections of the Old Testament in The Bible, no mention is made of any kind of cognitive processes such as introspection, and he argues that there is no apparent indication that the writers were self-aware. According to Jaynes, the older portions of the Old Testament (such as the Book of Amos) have little or none of the features of some later books of the Old Testament (such as Ecclesiastes) as well as later works such as The Odyssey, which show indications of a profoundly different kind of mentality—an early form of consciousness.[3]
Jaynes noted that in ancient societies, the corpses of the dead were often treated as though they were still alive (being seated on chairs, dressed in clothing, and even fed food) and he argued that the dead bodies were presumed to be still living and the source of auditory hallucinations (see ancestor worship).[3] This adaptation to the village communities of 100 individuals or more formed the core of religion. Unlike today's hallucinations, the voices of ancient times were structured by cultural norms to produce a seamlessly functioning society.
In ancient times, Jaynes noted, gods were generally much more numerous and much more anthropomorphic than in modern times, and speculates that this was because each bicameral person had their own "god" who reflected their own desires and experiences.[4]
Even in modern times, Jaynes notes that there is no consensus as to the cause or origins of schizophrenia (the subject is still hotly debated). According to Jaynes, schizophrenia is simply a vestige of humanity's earlier state.[3] Jaynes noted that many schizophrenics have "command hallucinations" wherein the "voices" command the schizophrenic to commit certain acts. In Jaynes' argument, these command hallucinations are little different from the commands from gods which feature so prominently in ancient stories.[3]
