If you think about schizophrenia long enough, you're forced to the conclusion (however uncomfortable) that each voice is an independent network of neurons that lives inside the brain. But these voices aren't just passively housed in the brain — they're alive in there, in a very real sense.

If we have trouble accepting this, it's because we're chauvinists. We fancy not only that our 'selves' are in full control, but also that our selves are the only locus of control and intelligence in our brains. (We're especially fond of this idea here in the modern West.) In the 'government within', our selves claim absolute authority. Occasionally we'll grant some kind of intelligence to our unconscious minds, but we imagine that it's all somehow done in service to 'us' — that it's really somehow our intelligence. We reject, with extreme prejudice, the notion that the brain could harbor any independent intelligence, with an agenda other than our own. And if such a 'rogue' intelligence could somehow command verbal skills and talk to us — why, that would be truly subversive.

The difference is that, in a typical modern brain, the rogue network exists at a much lower level, whereas the gods in a bicameral brain exist at (more or less) the same level as the self and, crucially, can call upon the language and reasoning faculties directly.

In many ways you would have been just like a typical modern human. The crucial difference is that you would have experienced occasional, or perhaps frequent, auditory hallucinations: the voices of your god or gods. You would have heard them clearly and distinctly, as though they were actual voices coming from the outside world (much like today's schizophrenics). The voices would speak to you in the form of commands, admonishment, and advice. Sometimes they would have been accompanied by visual hallucinations as well, whether as an anthropomorphic figure (very rare) or simply as a visual glitch — like a swirling mist or burning bush, similar to what people experience today using psychedelics.

The gods were in no sense 'figments of the imagination' of anyone. They were man's volition. They occupied his nervous system... and from stores of admonitory and preceptive experience, transmuted this experience into articulated speech which then 'told' the man what to do.

According to Jaynes, a child in a bicameral society learned to hear his voices by internalizing the advice, admonishment, and direct orders from his parents and other authority figures. As he grew up, he would internalize other voices, such as those of his bosses, priests, or political leaders. Along the way he would be actively coached in this process, and aided by external triggers like special awe-inducing spaces (temples, shrines), special hallucinogenic images (statues, idols), and special substances (incense, drugs).

In this way, god-identification might not have been so different from the identity crises experienced by adolescents today. A high-schooler vacillating between an artistic and an intellectual identity is in some sense being pulled toward two different gods.

The fact that it's not always easy to identify one's gods resolves a puzzle that had long baffled me: Why Yahweh keeps reintroducing himself (to Isaac, Jacob, Moses, Isaiah, and others) as "the god of your fathers."

I always used to think: There's only one God, right? So if Moses heard a voice, wouldn't he know whose it was? And why the reference to Moses's ancestors? But now I understand. Exodus was written for an audience familiar with the problem of hearing voices (plural) and trying to identify them — and Yahweh's remarks make perfect sense in this context.

Jaynes postulates that this mode of social control, facilitated by the bicameral mind, is what allowed large, dense, hierarchical city-states to form in the first place.

Incidentally this is also what happens with words (another psycho-social phenomenon), only the effect is much weaker. A word like "art," say, exists in some neural representation in your brain, but it also exists externally as a cultural concept. Whatever people are saying about "art," then, can affect you in a very direct way. This is why we're always fighting over what "art" means, what its boundaries are, etc. If our whole culture comes to agree that software is a form of "art," for example, then you'll automatically start to conceptualize software differently, and perhaps change your relationship to it.

So too with the gods — except that a 'god' or 'spirit' in your brain has a lot more power than any word, because it's alive in there. It's a fully animated concept, with agency of its own. As it happens, words aren't completely dead and lifeless; they're just like little fledgling gods. They can pop to mind unbidden, shift in meaning, and become more or less salient. But they have nowhere near as much intelligence or independent agency as a hallucinated voice.

From Gilgamesh to the Iliad, from the Old Testament to the Code of Hammurabi, from private letters to the most public steles — all portray an intimate, visceral, real relationship between gods and humans. This is so utterly different from the kind of relationship we see today (between the Abrahamic God and His followers) that I had always just assumed that the ancients were being poetic, manipulative, delusional, or some combination thereof.

Today our God is abstract, distant, formless, and silent — in other words, merely conceptual. This is what happens when a god becomes neurologically weak. And paradoxically, it's exactly what allows him to be portrayed as omnipotent, omniscient, etc. He becomes, in effect, a blank slate on which to project all of our most grandiose ambitions.

If they seemed all too human, it's because they're ontologically the same type of creature as a human.

Now imagine what it must have felt like to have the gods abandon you. Your god-voices were the source of some of your most important intuition and volition. It would be like suddenly having no basis for making decisions.

Today we know perfectly well how to make decisions: we think about our goals, list out our options, listen to reasons, evaluate and weigh all the evidence for each option (including some of our inarticulable feelings), and ultimately choose whichever one is best.

But the idea of a "conscious, reasoning will" was a set of protocols and a way of thinking that had to be invented (and catch on) sometime between 1250 and 500 BC, once the gods stopped acting as people's volitions. And in the interim, people probably used a number of techniques to compensate for their missing gods.