http://www.julianjaynes.org/bicameralmind.php

Julian Jaynes wrote one of the most amazing books in history on the evolution of consciousness. In it he speculated about a visionary state of awareness predating modern consciousness which he calls bicamerality. But Jaynes was not bicameral, himself — and thus had to guess about what he was writing about. Unlike Julian, I -am- bicameral. I know what he was writing about — firsthand.