Okay, so apparently I lied, and this is still interesting to me. This time, though, I'm going to try to play devil's advocate. Please understand that I don't necessarily believe the arguments I'll make in this thread, but I intend to do my best to argue in favor of the Biblical flood myth as representing an actual global event. So, here we go:
Arguments have been made that the flood was not catastrophic or violent, that water flows uphill, that the opening of the fountains of the deep doesn't mean water reaching high in the atmosphere, that water wasn't in the mantle pre-flood, but got there afterwards when the "single land mass" divided in the days of Peleg.
In the distant past we've discussed this topic, touching on Walt Brown's hydroplate theory and vapour canopies etc, but it would be worthwhile to discuss this subject in light of the ongoing thread "Evidence for a recent flood". In that thread many claims are made regarding the source of the flood water. Discussion of that would be off topic in that thread (I think) and it would be useful to have all the claims together in one thread.
As has been mentioned many times on this forum, there simply is not sufficient water currently on the Earth to allow a global Flood to have occurred as described in the Biblical story, covering the mountains and killing all life aside from that which was preserved on the Ark.
The answer, then, is that the flood itself was
miraculous, and that God literally used magic (or however one wants to describe deific omnipotence) to create the water as He created the Universe, and then took the excess water away afterward. The water was not drained to "hide evidence," as the Biblical God is not a trickster like Loki, but rather because as has been mentioned, if sufficient water existed on the Earth to cover the mountains, the mountains would still be covered.
To deny the possibility of a miraculous appearance/disappearance of the water unfairly discounts a valid hypothesis. It is conceivable,
though admittedly not probable through the lens of modern experience, that some agency used technology or other abilities to alter the water content of the Earth beyond normal naturalistic processes. If we're even allowing that the flood myth in the Bible might
describe a real global event, then we're also talking about accepting for the argument the existence of a deity who warned Noah, allowed him time to prepare, and put the entire sequence of events in motion. To accept that basic idea we're already talking about a being who can violate what we would call the laws of physics, because that level of prediction requires at a minimum either precognition (basically time travel, since it involves receiving information sent from the future), or the ability to set in motion a global flood.
This provides a problem: how do we tell whether the flood myth recounted in the Bible was representative of a real global event? With miraculous flood waters, the amount of water on Earth as we observe it today would be the same, either way.
The problem is somewhat akin to a criminal investigation, where the perpetrator of a crime has deliberately tried to cover his tracks, or to even place evidence that would mislead investigators. This is not to say that deception was God's motivation, however - remember, so long as that amount of water exists on the planet, the whole of the Earth would remain flooded as sea level would be a higher elevation than any land mass. God had to
add and remove water from the Earth in order to create a flood, if there was going to be a global flood at all.
So what, then, should we look for? We have one potential hypothesis in which the evidence in question would be the same regardless of whether the flood happened or not.
The answer is simple: we need to ask ourselves what else
we would expect to see, both if the world had been flooded, and if the world had not been flooded, and then examine the evidence to see which hypothesis best represents the world we actually live in.
Off the top of my head, one thing we would expect to see would be the frequency of myths, legends, and religious stories involving global floods, either as creation myths or as divine acts to cleanse the world of the wicked. The survivors of the Flood were all parts of Noah's family - after a few generations and tribal migrations as the human population recovered, we would expect the tale to be retold and slightly changed across multiple different cultures. Since all cultures would of necessity trace their ancestry back to Noah's family, it's conceivable that some tribes would eventually regard the flood as a creation event - in a way, it was
the beginning of the world, because the old world was swept away and drowned.
We would expect to see more of these flood myths (specifically dealing with divine punishment or creation) if the flood was an actual event than otherwise, because many myths and legends are at least based loosely on true events, and because a global
flood is sufficiently specific to make spontaneous similarity (similar stories arising in multiple cultures independently) unlikely.
And of course, when we look at cultures around the globe, we find that flood myths are extraordinarily common. They exist in cultures from every corner of the world.
I realize that the topic of this thread is the origin and destination of the actual flood water - but I think that sufficient evidence has already been posted so as to make the question moot. Clearly, there is not today enough water to flood the Earth as described in the Bible. Clearly, there was not sufficient water on the Earth before
the flood. In either of those cases, the Earth would simply have been flooded.
The answer, then, regardless of how improbable, has to have been
some additional mechanism capable of adding and removing that volume of water to the Earth. Hypotheses involving extant water have simply been ruled out, and the remaining hypothesis space including a global flood requires for the water to have been added and removed.
Since we know of no natural process that would allow for such a volume of water to be added and removed, we know we need to find an additional factor for our equation. We're missing a necessary term.
And the very Bible that leads us to investigate the possibility of a global flood also gives us the missing piece of the puzzle: an omnipotent deity, who earlier in the same narrative created the entire Universe ex nihilo.
If God created the entire Universe, where water is the second-most-common molecule in existence, certainly He could have created a bit more
water on Earth and then removed it once His purpose was accomplished!
The claim is
unfalsifiable, at least so far as quantities of water are concerned. That particular bit of evidence would look the same to us, either way. But when we have exhausted the alternatives, the remaining hypotheses, however less probable they seemed at first, must
contain the truth. Even if those hypotheses require something as improbable and untestable as divine intervention. Science cannot
exclude potential hypotheses - what we do not understand today, we may
understand tomorrow. "Magic" carries significant negative connotations in science, but the simple fact is that sufficiently advanced technology, or indeed any
phenomenon will be indistinguishable from "magic." My cell phone would appear to work by magic to a person from three centuries ago.
And the God of the Bible is no trickster. He would not lay false trails and attempt to deceive His own creations - if He were that sort of God, He wouldn't have bothered to leave us the Bible at all to recount the true story.
So while this one bit of evidence would look the same either way, we must shift our focus to other observations, other facts about the world that would be different if the Earth had or had not been flooded.
How'd I do?
The human understanding when it has once adopted an opinion (either as being the received opinion or as being agreeable to itself) draws all things else to support and agree with it.
- Francis Bacon
"There are two novels that can change a bookish fourteen-year old's life: The Lord of the Rings and Atlas Shrugged. One is a childish fantasy that often engenders a lifelong obsession with its unbelievable heroes, leading to an emotionally stunted, socially crippled adulthood, unable to deal with the real world. The other, of course, involves orcs." - John Rogers