Jaynes’s theory can be broken down into four independent hypotheses:
1. Consciousness — as he carefully defines it — is a learned process based on metaphorical language.
2. That preceding the development of consciousness there was a different mentality based on verbal hallucinations called the bicameral (‘two-chambered’) mind.
3. Dating the development of consciousness to around the end of the second millennium B.C. in Greece and Mesopotamia. The transition occurred at different times in other parts of the world.
4. The neurological model for the bicameral mind.