The way some of the stories are clearly cobbled together from divergent accounts implies that they started out as spoken fables and that there was at least some kind of editorial process when they were being recorded. Although I think it's less of a process where various people worked together to hash out a version as much as it was that succeeding writers decided to add their two cents or modify what was already there. Stuff like the creation account and the two versions of the ten commandments makes you wonder just how many versions of those stories made it to 'paper' before being wiped out forever.
"Well, evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape- like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered."
-Stephen Jay Gould
-Stephen Jay Gould
