Having examined and now largely rejected Julian Jaynes' theory of the origin of consciousness, I'd like to take a look at where we're left.
I think it's safe to assume that ancient peoples had no clear notion of the subconscious. When they experienced feelings or reactions they could not explain, it would be natural for them to ascribe these strange sensations to the influence of an outside force – gods, or spirits, or demons.
We can see this clearly enough in the word panic, which stems from the Greek god Pan, the god of wild revelry and carnal indulgence. People "in a panic" were thought to be possessed by Pan. The same mentality crops up in the New Testament in the many stories of people who are possessed by demons, and who can be cured only by exorcism. The idea that the insane are possessed by some god, and that poets are essentially madmen, crops up in Plato, among other places. "Inspiration" originally meant breathing in or absorbing the spirit of a supernatural being.
In this light, we can take a new look at some of the examples that Jaynes cites in support of his theory. Take the scene in the Iliad when Achilles, almost overcome with rage, finds himself violently restrained by the hand of Athena, who swoops down from heaven to grab him by the hair and warn him off. This could very well reflect a primitive understanding of a seemingly causeless emotional upheaval and inner conflict. In the Iliad's battle scenes, the heroes are often spurred to violent acts by the urgings of gods, just as men in battle even today may find themselves fired up by adrenaline, crowd psychology, and long-suppressed emotions that they cannot readily understand. Later they may look back in amazement at their apparent fearlessness, even recklessness, and wonder how they were able to do it. In an age haunted by gods, the simplest answer would be that some god or other took over the person's body and used him for the god's own ends.
Jaynes also spends a good deal of time talking about the Greek oracles, notably the oracle at the Temple of Apollo. He sees these oracles as holdovers from the bicameral age. But another possibility suggests itself. If the primitive psychology of the era conflated hysterical behavior with possession by a god, then what would be more natural than to induce hysteria in some highly suggestible subject in the hope of bringing about this kind of spirit possession? This might explain why the prophetesses of the oracles were typically young, naïve, illiterate farm girls, precisely the sort of subjects who might be most easily whipped into a frenzy, given the proper training and the appropriate commands by authority figures (the temple priests). As Jaynes himself points out, these girls typically did exhibit wild, frantic twitches and gesticulations before issuing their oracular pronouncements.(It is an open question whether the pronouncements themselves derived from the girls' subconscious, the suggestions of the priests, or some spirit-world source. Quite possibly, the answer is: all of the above.)
But none of this necessarily indicates that people behaved this way all the time – that they felt themselves to be at the mercy of the dictates of gods even in their casual, everyday activities. Nor does it suggest that people of this era were automatons who had no sense of self, no ego, no distinct personality, and no ability to introspect.
The plethora of idols in the ancient world, which were found everywhere from massive ziggurats to small shrines in humble homes, certainly implies that some form of idol worship, or communion with idols, was central to daily life. The exact nature of this communion probably cannot be recovered now. Perhaps people did go into a sort of hypnotic trance while staring into the large eyes of these carved figures, in order to activate otherwise inaccessible parts of the brain. In Ezekiel 21:26, we read that the king of Babylon has "questioned the household gods," a casual reference suggesting that such consultations were far from rare. We know from ancient Mesopotamian documents (cited by Jaynes) that people took great stock in the "utterances" of the gods and prided themselves on their ability to "hear," sometimes appending the name "True of voice" to their given names. It is likely that the ritual of washing a statue's mouth was connected with the desire to coax the statue into communicating. We also know that later cultures deplored the vanishing of the gods and begged for them to return. Jaynes quotes many such statements, such as these lines from The Babylonian Theodicy (ca. 900 BC):
May the gods who have thrown me off give help,
May the goddess who has abandoned me show mercy.
The Psalms also are dense with appeals to Yahweh to show himself, make himself known, not abandon his people, etc. Everything points to "the disappearance of God," to borrow a title from Biblical scholar Richard Elliott Friedman. Sometime during the long process of building civilization, man's contact with the gods (or spirits) became tenuous and unstable.
I would suggest that Jaynes is right about this much: the progress of literacy and the growing complexity of civilization and trade encouraged left-brain dominance, which in turn tended to inhibit the activity of the right cerebral hemisphere, the doorway to spirit communications (and psi). As left-brain, linear thinking became standard, the more intuitive, psychically active, mediumistic functions of the right brain were less likely to develop; these talents tended to remain dormant or inaccessible. Hence the laments for the vanishing gods, the silenced voices, the lost visions. And later, after a left-brain orthodoxy had been established to supplant the voices and maintain social control in other ways, repeated efforts were made to suppress the last vestiges of channeling, sometimes by violence.
The question has been raised – and it's a good one – as to why ancient peoples would receive such angry, militaristic instructions from their spirit guides. Here are some possibilities that occur to me.
First, in many cases people may have been confusing their own subconscious impulses with spirit possession, as described above. The less-than-edifying messages may have been their own subconscious urges, misinterpreted as divine guidance. This kind of thing happens even today, in cases of psychopaths who claim that God told them to kill.
Second, the extent or degree of these violent messages may be exaggerated in some of our texts. There are many episodes in the Torah (the first five books of the Hebrew Bible) in which Yahweh orders his people to commit massacres. But almost all scholars agree that these books were compiled and redacted a long time after the events they purport to describe. The most plausible scenario is that significant parts of the Torah, and possibly other books like Samuel and Kings, were put together during the reign of King Josiah in roughly 600 BC for purposes of reviving religious traditions; this material, trumpeted as having been miraculously rediscovered, was claimed to have been written by Moses ca. 1400 BC. The Exodus story was probably invented, or at least significantly embellished, during the period of the Babylonian Captivity which closely followed Josiah's reign; the story would have been a response to the humiliating enslavement of the Israelites (with Egypt standing for Babylon in these tales). In short, a great deal of the violent, wrathful, destructive personality attributed to Yahweh was invented by a priestly caste of storytellers working for propagandistic ends. These stories almost certainly do not reflect the actual communications received by ancient peoples.
Finally, in a rough and unsettled world, it may have been necessary to use violence in ways that disturb us today. If a certain population was more intellectually advanced than its competitors, there might well be a long-term value in the survival of that population that would justify extreme measures in its own defense. Perhaps the only way for humanity to make progress, at least in the early stages of civilization, was by weeding out the populations that were holding it back. A rather Darwinian notion, to be sure, but could history as we know it have ever gotten started if the first cities had been wiped out by the raiders from the hills? (Sam Barone's novel Dawn of Empire is an entertaining depiction of this conflict, though some of the historical details – notably, the use of coinage and cavalry – are wrong.)
Below is a carving (ca. 1250 BC) reproduced in Jaynes' book. It shows the god Sharruma embracing a Hittite king, Tudha-liys. Jaynes naturally interprets the god as the hallucinated voice/vision that guided the king throughout his life. Note that the god is on the king's right side, consistent with the idea that the hallucinations originated in the right brain. But an alternate interpretation is possible. Perhaps Tudha-liys actually was in contact with a spirit guide, via mediating structures in the right cerebral hemisphere. Later, such close contact between the physical world and the spirit world was largely lost; and for centuries afterward, poets and mystics longed for that golden age when men and gods spoke face to face and walked hand in hand.
Carving as reproduced in The Origin of Consciousness in the Breakdown of the Bicameral Mind.