Now it is time for Jaynes to introduce what he calls the bicameral mind.
By this, he means a mind that is capable of thinking, making decisions, doing, and recalling, but one that is not conscious of doing any of these.
But, it didn't "metaphorize" about how itself was thinking. A thought appeared to the bicameral mind much as it does to yours - out of the blue. But the bicameral mind didn't wonder where it came from or who it belonged to. There wasn't any self for it to belong to, so it must have come from somewhere else. From a god perhaps ...
The input to the divine hallucinatory aspect of the bicameral mind was auditory. It used cortical areas more closely connected to the auditory parts of the brain.
You could do rather a lot with this sort of mind. If it tells you to plant every spring, you do, and you would survive until the next spring. If it told you to tell others to plant every spring, you'd all survive (and you'd achieve a level of fame).
And, it isn't as if I'm claiming that humans aren't mentally superior to animals. Think of all the things you do every day that are bicameral in nature. Just to exit your car you have to hit the brake, hold the brake, sense a stop, slip the car into park, check that it is there, release the break, check again, turn the key, and open the door. You're not conscious of any of those, for the most part. And yet, could they be commands barked at you by a driving instructor? Are there in fact commands barked by your driving instructor stored somewhere in your memory? The big difference between you and a schizophrenic is that you've turned down the volume on those commands way down.
There is no reason why a bicameral mind couldn't talk or write. The latter is really interesting because of how we read - we hear the words spoken inside our head.
So, your primitive, but civilized, and someone teaches you to read and tells you that the words you see are from a god/king/overseer. It's not a stretch to then think that the voice you hear in your head is the god/king/overseer. That is the essence of the bicameral mind: the ability to recall and replay commands in the voices of people other than yourself.
You could do a lot with that. Again, think about yourself. Is there a recalled voice inside you nagging you to get away from that stupid blog and do something productive? Who exactly is that if your conscious mind is doing the reading?
But, there's a problem in running a society based on transmiting commands for the recall of bicameral minds:
And once the word of god was silent, written on dumb clay tablets or incised into speechless stone, the god's command, or the king's directives could be turned to or avoided by one's own efforts in a way that auditory hallucinations never could be. [pg. 208]
A dog probably can't stop recalling the voice of his master saying "don't dig" or "stop barking". They may not be able to carry through on that, but it isn't like they can substitute some other recalled memory like "do go ahead and dig" or "it's OK to bark now".
But you ... you can recall the voice of the driving instructor telling you not to roll through stop signs ... and you can rationalize that if you stretch that rule a little bit at this junction, maybe, just maybe, the memory of the driving instructor won't come back to haunt you.