This theory was first brought to my attention when I was doing research on religions and the origins of religion. It is well known today that we have a split in our brains; basically is is considered to be two sided. This is the actual definition of bicameral. Bi meaning two and cameral meaning mind. Or something like that.This theory was thought up by Dr. Julian Jaynes in his book, The Origin of Consciousness in the Breakdown of the Bicameral Mind, which you'd probably rather not read. It is sort of boring, unless you are really into the whole concept. in a nutshell, the theory states that for thousands of years humans weren't conscious in the same way that we are today. He said that the two halves of the brain were separate in that one half was the 'man mind' and the other the 'god mind.' (My terms there, not his.) Basically the god-mind controlled the man-mind in something akin to a puppet master pulling strings.So you had a society made up of schizophrenic members. That was the norm. If the god-voice was loud enough, perhaps it would start to dictate and the man-mind would write down the thoughts. These were the basis of early religious writing. (Remember I am just paraphrasing the theory, not necessarily espousing it.) The more the god-mind was conscious, the more likely the person was to become "the voice of god" or better known as a prophet. This went on for quite a long time. Eventually through evolution of our minds, the two halves of the mind blended and the god part became our consciousness.Today if someone hears voices in their head they are considered mentally unbalanced. Thousands of years ago they were revered. Are we making progress here or what? Maybe not. Are the voices really just a part of someone's more primitive state, or are they perhaps actually communication from another plane? I know this is 'out there' and I am not saying one way or another what is truth with a capital T. I know I don't know one way or the other.I do believe that prophets of old merely had to convince themselves that they were hearing god, and then convince others of the fact; then a new religion could start. It still is happening today. Are the charlatans in fact messengers from god? There are new religions forming all the time. To have more acceptance, many of them a branches of established religions. You can look at the Lutheran movement, if you want to go back in history a ways, or you can check out Mormons or Jehovah's Witnesses for early 20th century examples. Newer examples might be Branch Davidians, Heaven's Gate or militant Muslims.It is a scary thought to think that all the rules and commandments might just be the product of split personalities thousands of years ago. Another thing to think about it is, what if someone who is locked up in a mental institution really is a true prophet of God, but is in a rubber room and can't get the message out.