My theory is that God could have communicated the bible to a human being, who wrote it down. The problem is, that person may have not copied down the word of god exactly. Let's say that they did, for all intensive purposes. But how many people have laid their hands on the Old Testament? Probably millions, if not billions. Each person who copied the Old Testament, or any bible for that matter, could have changed the wording slightly. Even if not purposely, I find it hard to believe that a huge document like the Old Testament could be copied down without any typos or errors at all. My point is, even if a bible originally was the word of God, there's no way it was preserved word for word after so many people have laid their hands on it.