The origin of consciousness in the breakdown of the bicameral mind

Bicameralism (the philosophy of "two-chamberedness") is a hypothesis in psychology that argues that the human mind once assumed a state in which cognitive functions were divided between one part of the brain which appears to be "speaking", and a second part which listens and obeys—a bicameral mind. The term was coined by psychologist Julian Jaynes, who presented the idea in his 1976 book The Origin of Consciousness in the Breakdown of the Bicameral Mind, wherein he made the case that a bicameral mentality was the normal and ubiquitous state of the human mind only as recently as 3000 years ago.

Jaynes asserted 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, the bicameral individual was guided by mental commands believed to be issued by external "gods" — commands which were recorded in ancient myths, legends and historical accounts. 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: the ancients literally heard muses as the direct source of their music and poetry.

For example, in the Iliad and sections of the Old Testament no mention is made of any kind of cognitive processes such as introspection, and 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 few or none of the features of some later books of the Old Testament (such as Ecclesiastes) as well as later works such as Homer's Odyssey, which show indications of a profoundly different kind of mentality — an early form of consciousness.

http://s-f-walker.org.uk/pubsebooks/pdfs/Julian_Jaynes_The_Origin_of_Consciousness.pdf