Please excuse me while I argue with myself.
1. The Bible was written for the simple people of that time and used images and metaphors because that’s what people could understand. We’re smarter, so we can discard that now.
You’re no smarter than the people who first listened to Moses. If they needed images and metaphors, you need them too.
2. It’s all lies! Silly fables! Let’s just have done with it.
Even if this weren’t the word of God we’re talking about, that would be a silly thing to say. Sure, it seems next to impossible that all the world’s animals really descend from those on the Ark. Still, a story like the Flood, shared by peoples all over the world, has got to be more than just the product of some random storyteller’s imagination. Perhaps there was some event that all peoples vaguely remember. My suspicion is that every legend has some basis in fact. But even if you don’t believe this, it’s pretty remarkable that this story is so widely shared. If we assume nothing like what it describes ever happened, then it means either that lots of peoples independently keep recreating this story, or else this story has some sort of special appeal that it transmits quickly from people to people, even when they’re not much interested in other aspects of each others’ culture. Either way, we have the sense that this story is some kind of given, an archetype not manufactured but discovered, a truth of the human imagination if not of natural history. It is certainly worth getting to the bottom of.
3. It’s all well and good to say that Genesis is really giving us symbols of spiritual truths, but to be credible as anything but face-saving in the face of scientific disproof, you’d better be able to say exactly what the symbolism is, and why it had to be related in this way rather than plainly and literally.
If I could tell you exactly what the symbols say, then there wouldn’t have been any need for them, and they would ipso facto not have been necessary. Symbols are not code for literal propositions; they exist to express truths and connections that can’t be expressed with literal propositions.
4. But the only reason you’re looking to chuck the literal–in the modern sense of that word–meaning is that you’re embarrassed by it. The authority of the Bible doesn’t lead you to these weird interpretations, just the fact that you don’t believe what the Bible is telling you. That means that, whatever you may tell yourself, there actually are authorities that trump the Bible for you. Why not be honest with yourself? If you can’t salvage your faith, at least preserve your honesty.
That’s mean. Especially since I’ve already expressed my hunch that there is some historical kernel to all of this. I don’t pretend to have any general principles to offer, but a guideline is to notice when scripture is expressing the inexpressible. For example, Genesis begins with God about to impose form on the Earth, and the chaos of formlessness is represented (as it is for pretty much all peoples) by the primordial waters. Now, in reality, formlessness is one thing that the human mind can’t truly conceive, because the way to think about anything is precisely to extract the form. All our ideas about space, time, mass, and energy are formal aspects of material being. And even after God forms the world, the primordial waters remain as a sign of whatever lies beyond the realm of intelligibility, a beyond about which, by its very “nature”, we can say nothing direct. I suspect that all peoples retain this intuition that beyond the realm of order is a vast chaos, not a mere absence of being, but something active, always ready to crash in on the ordered realm, dissolving form and identity, destroying and renewing. Thus the resonance of the story of the Ark, since indeed the ordered realm is conceived as itself a sort of Ark surrounded by the primordial waters.
Could it be true, that some physical, psychological, or social force of chaos once overwhelmed humanity? If so, it could only properly be remembered by myth.