https://en.wikipedia.org/wiki/Bicameralism_(psychology)
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 person would hallucinate a voice or "god" giving admonitory advice or commands and obey without question: one would not be at all conscious of one's own thought processes per se.