My initial hypothesis was that when Proto-Indo-Europeans arrived into Levant, they brought non-duality (and Cannabis) with them, which, when introduced to animistic societies, resulted in emergence of hierarchical social structures centered around polytheistic and in some cases monotheistic religions. You can preview my main starting points in a response I made here.

However, the more I looked into it, the more it became clear that that hypothesis is untenable, and what transpired was much more complex than my initial linear (and rather naive) assumption.

First, although the connection of non-duality and Cannabis is rather clear-cut as I have written elsewhere (this is also supported by the fact that I could not trace any instances of non-dual understanding in pre-columbian Americas where Cannabis was absent), there is absolutely no evidence of non-duality existing before c. 2000–1500 BCE. Thus, it pretty much correlates with mainstream theories of how Indo-Aryans spread this knowledge during their migration from Pontic-Caspian steppe, and it is also further highlighted by e.g. events in Egypt (use of Cannabis from c. 2000–1700 BCE and Akhenaten’s attempts at establishing a “modern” monotheistic religion during 14th century BCE).

So, according to my initial hypothesis, there would be 1–2 millennia gap between emergence of hierarchical societies with polytheistic religions at their center and arrival of non-duality on the historic scene — definitely a no-go.

Second, I was caught off guard when I looked at the oldest animistic societies still surviving on Earth. Particularly that none of them use hallucinogens, and, although their overall worldviews within the culture are (sort of) identical, the actual customs among various bands vary to a large extent (e.g. some Pygmy groups are strongly monogamous while other groups are polygamous, there is different degree of customs appropriated from other cultures, etc.). It’s also interesting to see the strong emphasis they put on sex as a source of life (maybe as a compensation for awareness of mortality?).

Another funny coincidence is that there are essentially two pharmacological classes of the most widely used psychedelics — first are serotonergics (mescaline, ergot, psilocybe, ayahuasca, iboga) and the second are cannabinoidergics (well, cannabis). Makes one wonder (when, as it seems, cannabis was associated with tree of life) what could ancients consider to be the tree of knowledge of good and bad (serotonergics, as opposed to Cannabis, certainly take one completely into “another wold”, and the same can be also said about deliriants and dissociatives even though they are in their own pharmacological groups). But I digress.

All in all, I scratched that initial hypothesis.

It became clear that religions arise when we “invent god (or a complete pantheon of gods), an instrumentality through which the wholeness of existence and its various aspects operate, but which can be separated from community as well as individual,” and the shaman is elevated to the position of a priest. So, a religion is born when a society co-opts a worldview and establishes ceremonial rituals (as opposed to communal ones) which put common folks in the role of mere spectators, and it is used solely to solidify a hierarchical society and give the ruling elites an ideological footing. In this way animism becomes a polytheistic religion, non-duality becomes a monotheistic (or henotheistic) religion, and atheism turns into a religion of scientific naturalism (with justifications such as social Darwinism, derision of everything non-intellectual and irrational, and similar).

It also became clear that it most probably originated within groups that had a predisposition (that later solidified into a culture) for use of violence, raiding their neighbors for resources, subjugating even the members of one’s own tribe, etc. (similarly as we can observe significant cultural differences within otherwise uniform Pygmy population).

Just for illustration, here’s a rough timeline (mainly Levant):

• c. 330000–230000 BCE : Homo naledi burials that hint at the awareness of mortality (maybe also the very birth of symbolic thinking)
• c. 65000 BCE : Neanderthal animistic cave paintings — first clear evidence of symbolic thinking
• c. 42000 BCE : emergence of Sapiens’ animistic art (cave paintings, zoomorphic and anthropomorphic figures, etc.) which continued almost unchanged till the neolithic revolution
• c. 30000–28000 BCE : Sungir burials — most probably the oldest known shaman burials (but it’s just a speculation)
• c. 12000 BCE : Natufian shamaness — burial site of an elderly female (c. 45 years), similar to Sungir graves, but with more elaborate inventory, and remnants of a huge funeral feast
• c. 12500–10000 BCE : Neolithic revolution
• c. 10000 BCE : Jericho
• c. 7400 BCE : Çatalhöyük — large egalitarian city (median estimates 8000 people) that was abandoned around 5100 BCE
• c. 6000 BCE : First fortified settlements in Levant (e.g. Tell es-Sawwan)
• c. 4500 BCE : Enki’s temple in Eridu
• c. 4400 BCE : First clear evidence of organized warfare (Tepe Gawra)
• c. 3900 BCE : Holy granaries, elite palaces, oldest known copper swords, and clear signs of food redistribution in Arslantepe, Anatolia
• c. 2000–1700 BCE : Cannabis used for medicinal purposes in Egypt
• c. 1500 BCE : Composition of oldest layers of Rigveda (oldest known non-dual scripture, although here merely in strict oral form)
• c. 1352–1335 BCE : Akhenaten’s “monotheistic” religious reform
• c. 1200–1150 BCE : Late Bronze Age collapse

Well, I hope this answers your questions.