For serious discussion of the controversies, approaches and enigmas surrounding the origins and development of the human species and of human civilization. (NB: for more ‘out there’ posts we point you in the direction of the ‘Paranormal & Supernatural
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Personally, I believe the flood myth arose from an actual flood. Problem is, there's lots of floods in the past. Big ones.
I don't see why similar tales wouldn't have arisen from completely different floods.
Once a culture has some sort of flood myth, it's easy to see how such myths from different cultures could be confabulated at a later date through cultural contacts. I mean, hunter gatherers sitting around the fire at a regional gathering place - such as Gobekli Tepe may well have been.