There's a story you might have heard, where there was a
flood, and much of the
Earth was covered, and many people died but some handful were saved, through good
fortune or
divine favor.
In one version of this story, a fellow named
Noah built an
ark and stocked it with
animals to ride out this calamity for well over a year. There are many
questions about the story and specific
challenges to the feasibility of the asserted construction and husbandry involved. But this is actually not one of those. This is, instead, a point about Noah's own
knowledge of the events as supposedly passed down by himself.
Let us suppose, in fact, that there was indeed a Noah who sincerely believed that he was hearing a disembodied voice (recalling that nobody else in the story hears this voice to corroborate it, so we're relying on a later writer asserting what Noah was supposed to have heard). And suppose Noah did indeed hear instructions to build an Ark, and stocked it with the animals which he was familiar with (which, to his somewhat parochially localized view, could encompass all the animals in the world as known to him).
Remember, Noah's version of the story doesn't specify any of the animals on the Ark except a very few species: specifically, "clean beasts" (almost certainly sheep and oxen) there for the
sacrifice desired by the voice he heard, and
ravens and
doves. There is no indication of what kinds of animals Noah knew to exist at all, really.
But if we suppose that there was indeed a Noah who floated for a lengthy period before running an ark aground somewhere, and this Noah believed the rest of mankind to be dead, he'd have no way to know that was true. Certainly he might've looked around and not seen anybody within eyeshot. He might've walked a few miles in this direction or that before concluding his family alone remained in the world. He might've told his children that they were all that was left, and as they went their separate ways in the world (as the story recounts), they would have believed this, and passed this knowledge to their children, and their children's children -- and it might well be that enough generations of them propagated and spread out for themselves that, by the time they encountered descendants of other survivors, they didn't realize that these weren't just more of Noah's dispersed offspring.
But there are, you see, other flood stories.
Gilgamesh survives a flood in a boat, and encounters other people who've done the same. Many cultures recount varying numbers of people (and animals) surviving in varying numbers of boats. One tradition found in the
Vedas has an entire nation surviving such a flood, warned of its coming and preventing inundation with barriers instead of boats. The Bible claims "on the seventeenth day of the seventh month the ark came to rest on the mountains of
Ararat" -- so one must wonder, how far can a large wooden boat with no mechanism for steering or powered movement drift in seven and a half months? A Noah who began to float in one part of
Turkey and ran aground around another, and remained in that vicinity would simply never have known about people in India, China, Australia, or even in Egypt and Mesopotamia.
There is some claim that
Moses -- who couldn't have any personal knowledge of anything before his time -- authored the
Genesis stories as well, but no trace of how he might've gotten that information, nor that he himself could have known of other cultures outside his
Mideast sphere of wandering. And so it can be credited that each of the varying mythic accounts, including the scriptural, does accurately reflects some historical experience from the limited perspectives of those who believed those experiences based on their localized knowledge.
It is in fact interesting that some point to the multiplicity of flood myths to attempt to use this as a factor limiting history do a single account, when a multiplicity of survivor accounts in different regions is a more logical explanation. This is especially so, given how both
genetic variation and the variations in descriptions of the survivors and means of their survivorship are largely irreconcilable with a single exclusively true account, and where there remain some cultures such as the Bantu and Khosa people of Africa who have lengthy oral mythohistoric traditions with no flood account whatsoever, indicating that whatever great floods may have occurred in the world's history, none reached their region -- and so none reach
reason.
Azul-din adds: Personally I like the Hopi version- surrounded by warlike and stronger tribes such as the Apache, the Hopi believe the world was destroyed not once but four times (once by a flood) by Tawa, and each time only a few good Hopi's survived, preserved by Spider Woman in holes in the ground.
And Tem42 adds: If a mythology is based even remotely on truth, and stretches back (for example) 500 years, then it should be expected to include a 500-year flood, a 500-year earthquake, a 500-year plague of locusts, etc. Large catastrophes aren't evidence of supernatural events; we should pay much more attention to mythologies that do not mention catastrophes that should statistically have happened. That's when the gods actually did something.