Today it means: The hypothetical mentality, neurology and sociology of the theory that before the historical emergence of introspective consciousness ancient humans and the earliest civilizations were governed by auditory hallucinations ‘spoken’ by the right cerebral hemisphere and ‘heard’ by the left hemisphere as the voices of gods. Full definition →
Coined by Julian Jaynes as a “rather inexact metaphor to a bicameral legislature of an upper and lower house” (1989) and appearing in his 1976 book The Origin of Consciousness in the Breakdown of the Bicameral Mind.
Etymology from Wiktionary, CC BY-SA 4.0.