While Christian Evangelicals will insist the Bible is factual — cover to cover — and that it should be taken literally, do not be deceived. The Bible is full of myth! How do we know this? Because countless stories found in the Bible are also found in other Mediterranean mythologies...Long-time readers will know that I don't have much truck with creationalists. I give them a fair shake - I think: I review their stuff, and then when it turns out weak fall back on my long-held position that I personally do not know how much of Genesis is to be taken literally. Some of it only makes sense when taken literally, not only that, but it fits into what we know archaeologically about the Ancient Near East. Some of it, I'll admit, is difficult to swallow*.
To use Noah and the Flood as an example — we know that the ancient Sumerians, Akkadians, Assyrians, and Babylonians all believed in the myth of the great deluge thousands of years before the Hebrews were even recognized as a people. The evidence is indisputable that this myth was adopted and redacted by the Hebrews to suit their own cultural objectives.
However, I tend to follow the "What would we expect?" school of history** at times, and flood narratives actually tend to fit that pretty well. If there were a huge flood that knocked out all of mankind but a few people, what would we expect? We should certainly expect that "the ancient Sumerians, Akkadians, Assyrians, and Babylonians all believed in the myth of the great deluge thousands of years before the Hebrews were even recognized as a people" - in fact, I've even used the Babylonian version here before. Since every people would by necessity be descended from the survivors, then we ought to expect that nearly every nation would have some manner of remembrance of it, however mangled. Which, coincidentally, is what we find. That the Sumerians had it "first" is simply a function of chronology - we have stuff that they wrote that is older than the Hebrews because the Hebrews came out of Sumeria after it was written. In short, if the Hebrews' version*** is true, then the evidence we find from the Sumerians is precisely what we ought to expect to find. Rather than evidence against the Hebrew story, its existence is evidence for it.
Does the fact that it passes the "What should we expect?" test mean it's true history? Of course not - it could still be myth - but it does mean that it's not "indisputable" that the Hebrews stole a story that existed only because those who came before them had a penchant for gripping fiction. The "stolen myth" motif does not explain how the Mi'qmak (feather) Indians taught that the flood was caused by the tears of the sun/god over the fact that the first family created started killing one one another off, with only 2 righteous people being saved from the ensuing flood, and who then repopulated the whole earth - a much closer parallel to the Hebrew than the neighboring Akkadian version, in which the flood was caused by gods concerned with overpopulation. Though I suppose that one could always propose that the Hebrews stole the story from a wandering tribe of Canadian Indians.
* that being said, God is God, if and he wants to put a talking snake in a garden a la Gen 3, I'm certainly not going to say he can't do so, nor will I be surprised if he tells me that he did when I stand before him in a few short years. It just seems representative of a religious truth, not unlike Pandora's wonderful jar in Greek mythology.
** I frankly find it more useful than the "x peoples crossed the x mountains in x bc" school, as in the book on the early Greeks that I'm currently reading. Where did they come from? Well they just showed up and started tagging the walls of Crete City in Linear B. We don't know where most people came from, nor when they showed up where they did. They cannot tell us and left no evidence for us to find. That's where our own myths about the Bering Strait land bridge come in so handy.
*** I won't say "Moses' version" as I don't think he wrote it.