First view: Any historical tradition and model of a particular polytheism is acceptable to follow, including a new modern one
Second view: There is only one historical tradition and model of a particular polytheism, before which things were undeveloped and after which things were in decline
Balanced view: There is a plurality of valid historical traditions and models to follow, but it is also possible to refine our research in order to select the better few.
This is a topic that has long occupied my thinking and seems to grow only more complex with time. Let us consider an example, as in the Hellenic polytheism, since a great deal is known about its various historical traditions; there is the Minoan period, Mycenaean period, the Homeric, the Archaic, the Classical, the Hellenistic, the Greco-Roman, and the Late Antiquity or Medieval period. These all constitute what may be called distinct historical traditions and models of Hellenic polytheism which people nowadays follow with variations. Within those historical periods, there are more sub-variations, as for example, with the philosophical schools or regional practices within Greece. Other polytheisms share this plurality of period, model and region, with more or less complexity. The question is, do we have a best one, better ones or are all of them alike? The balanced path that avoids extremes will acknowledge that there is such a thing as “better” (and conversely “worse”), but at the same time no absolute “best” or “worst”. The reason for this critical approach is that we are aware of certain historical changes and mistakes that had adverse consequences on (to continue the same example) Hellenic polytheism. These were unconscious changes and mistakes that took place with the force of circumstance, but although one cannot remove a certain degree of validity from them, it is possible to compare and analyze distinct periods and models in order to refine our view about Hellenic polytheism in general. Although we should take the Hesiodic principle of decline through time (which seems universal through cultures*) into serious consideration, we must also understand the value of what can be called a tradition’s “maturity”. In my view, Hellenic polytheism matured during the Archaic and Early Classical Period, only to decline not long after during the Late Classical Period without recovery**. Since this double-edged situation is sometimes more or less true for other polytheisms, it is necessary to reconcile the notions of decline and maturity fairly. This can be done by a method which posits a sort of “terminus ante quem” for each particular polytheism, whereby there is a “latest date before which” the validity of a historical model cannot be much questioned, and thus after which it can be. By following this method, which may at first seem arbitrary, it will become possible to select the better (more valid, more correct or more mature) models and distinguish them from the worse (the opposite). The following list is an initial attempt for several polytheisms, based on my previous research:
Celtic- before Roman invasion
Roman- before Middle Republic (thus allowing for Etruscan and others to exist)
Germanic- before Late Antiquity expansions
Egyptian- before Late Middle Kingdom
Semetic- before Hellenistic invasion (with exception to regions not conquered)
Slavic- before Late Antiquity
Chinese- before Qin Empire
Indian- before Mauryan Empire
Thracian and Illyrian- before Roman invasion
American, East Indies, Sub-Saharan and Oceanic – before Western colonialism
Lest this is taken as a hugely and unjustifiably arbitrary attempt, I will explain four points before I conclude. First, as the list seems to exclude important developments in religion, I will certainly concede that there is a great deal of religious and ritual knowledge that are dated after these afore-mentioned periods which we can’t dispense with. In such a case, we should be using what we have, in order to reconstruct a purer model and period without decline. The second point is, these periods are broad estimates that are not true for all regions that fall under a particular polytheism. For example, the Irish were not conquered by the Romans and therefore their period can last later than the rest. This is also true of the Indian and Chinese religious traditions (among others) that were unaffected by imperial influence and the times. Thirdly, these demarcations on religious tradition, which are meant to balance purity with maturity, do not exclude the arts, literature and so many other historical developments. For example, as a Hellenic polytheist who is seeking to follow a Homeric religious tradition, I value the art of the Late Classical and Hellenistic periods. And lastly, there will always be a considerable distance (in urbanized societies) between the religious tradition of the city and the rural areas, where the latter are always purer and less affected by dangerous innovations.
*The Hindus share this principle, and it seems to be a very common mode of thinking in societies that value ancestral tradition and purity of practice. This stands in direct contrast to the notion of “progress”, which (as far as I can tell) derived originally from the quasi-atheistical Epicurean philosophy which embraced atomic materialism. See Lucretius’s poem.
**Only true for areas affected by Athenian innovations, which by the Hellenistic period was almost every part of Greece (except the rural ones) and even beyond.