Based on the fact that there is virtually no description of mental states in the Ancient Greek classic The Iliad, where the protagonists are largely spoken to by Gods, Jaynes speculates that consciousness as we know it didn’t exist at this point in time and people experienced their thoughts as instructions from external voices which they interpreted as gods.
His book is a 1976 is a tour de force of interdisciplinary scholarship and although the idea that humans became conscious only 3,000 years ago is extremely unlikely, the book has been hugely influential even among people who think Jaynes was wrong, largely because he is a massively creative thinker.
Consciousness, Jaynes tells readers, in a passage that can be seen as a challenge to future students of philosophy and cognitive science, “is a much smaller part of our mental life than we are conscious of, because we cannot be conscious of what we are not conscious of.” His illustration of his point is quite wonderful. “It is like asking a flashlight in a dark room to search around for something that does not have any light shining upon it. The flashlight, since there is light in whatever direction it turns, would have to conclude that there is light everywhere. And so consciousness can seem to pervade all mentality when actually it does not.”
The Nautilus article is a brilliant retrospective on both Jaynes as a person and the theory, talking to some leading cognitive scientists who are admirers.
A wonderful piece on a delightful chapter in the history of psychology.
Link to Nautilus article on Julian Jaynes.