> You're taking a very modern view of Judaism, as a very clearly defined set of beliefs that cannot just borrow from other religions. Early Judaism (if that's even the correct term her, because this was a very different religion from what we now know) was not even clearly monotheistic.

Yes, as I said:

> Indeed, it’s most commonly believed that the Israelite religion was not unique, but a simple development into monotheism from a normal localized Canaanite religion.

Early Judaism was obviously polytheistic. The Flood story is almost certainly a story that dates back to those times, well before the Exile.

That said, by the Babylonian Exile, Judaism was clearly monotheistic and not "syncretic" (that's not how syncretism works anyway).

> The Epic of Gilgamesh predates Genesis by about 1500 years.

This is the issue. You're conflating the current academic consensus (very rough and subject to change) on the composition of Genesis with "when did the Genesis stories originate among the Israelites." Nobody thinks Genesis was written ex nihilo by some priests in Babylon and pressed on the rest of the Jewish population. (If nothing else, this would make post-Exile events totally untenable: how did they convince the non-Exile Jews of...anything?)

> The people who wrote Genesis would have known of the Epic of Gilgamesh. I do not find it convincing to hand-wave the identical details in the stories (like the story about beaching on a mountain and then releasing birds from the Ark to find dry land, until one doesn't return) as merely suggesting a common origin.

There's nothing handwavy about this. This is exactly how it works, in religions and myths across the world. Sometimes we've been able to trace it very clearly, as with Indo-Europeans. The more closely related the peoples, the more their stories match up. Two Semitic peoples in the same region having two near-identical stories without them having borrowed from one another is the least surprising thing in the world; oral tradition actually holds up pretty well in most cases (as documented in the original article.) This is in fact clearly supported by the theory of the composition of Genesis by multiple authors, with very slightly different narratives.

If you want to be more technical about the composition of Genesis, opinions vary, but the current consensus holds there were three or four main authors: the Yahwist, the Elohist, the Deuteronomist, and the Priest. The only one of these believed to date to the Exile is the Priest, with all the others predating it. The earliest source is believed to be the Yahwist, supposed to be writing in the 800s BC. Critically, much of the Flood story and the details about birds are specifically believed to originate with the Yahwist source before the Exile period.

> Babylon was a superpower of the time, both politically and culturally. The Israelites were influenced by it.

Yes, as I specifically said:

> It’s possible that this did happen. But it’s also the case that Babylonian contact was not new in the Exile period. The Israelites didn’t exist in a vacuum, they were part of the tapestry of the wider Semitic world for their entire existence and would have had familiarity with all these stories and beliefs the entire time.

Either way, all the Semitic versions of the Flood myth likely depend on a Sumerian original, along with the general influence of Sumerian myth on Semitic belief. (Personally, I have no problem with supposing that it was based on some real event and then the tale grew in the telling, just as Gilgamesh was a real king.) It's of course conceivable that before the Exile the Canaanites and the Babylonians crosschecked each other's versions, but it's not at all necessary. There was never any reason for "late" contamination of the story by Babylonians; the pan-Semitic influence always existed, and whoever the proto-Israelites were, obviously they were wandering around somewhere concurrently with the other Semitic peoples.

At any rate, the Babylonians were very definitely on the downslope during the Exile period, as evidence by their permanent fall from notability after their conquest by the Persians at the end of it. They and Egypt were the two regional powers Judah was stuck between at the time. Israel, of course, was earlier destroyed by the Assyrians, who had been a definite superpower but saw their glory days end with Nineveh.