Cash, I could, quite literally, expand on Paganism forever. I spend hours every day thinking, researching, discussing and writing about Paganism.
The best bet is to start with Wikipedia articles as a launching pad. Modern Paganism is incredibly diverse, from relatively new religions to the actual reconstruction of ancient religions. Wiccanate Paganism forms the majority of the modern Pagan movement. Unbroken indigenous religious traditions such as Shinto, Hinduism, Santeria, Vodou and Native American Spirituality are not considered strictly Pagan, but have a cousin relationship to modern Paganism. Most forms of Paganism, but not all, draw on the indigenous religious practices of Europe, the Mediterranean and the ancient Middle East.
Pagan comes from paganus, which means country dweller. As people in rural areas were usually the last to convert to monotheism they became known as pagans. Heathen is a term that has a similar origin. Most people feel that Pagan is a word that needs to be reclaimed with pride. There is a minority movement that rejects the term Pagan in favor of the term polytheist.
The various forms of practice and theology that fall under the Pagan umbrella can be overwhelming to take in at first. There are religions such as Asatru, Hellenismos and religio Romana that are reconstructed from ancient records and adapted to a modern sensibility. These tend to be oriented towards family and community, tend to be polytheistic and tend to be more conservative than other Pagan religions. There are religions like Romuva, the religion of the Mari people and other pockets of Pagan survivals. These are a bit controversial regarding their historical claims and very fascinating. Then there is Wicca, modern Druidry and Wiccanate Paganism, which are new spiritual traditions that get their inspiration from ancient paganism, ecology, feminism, GLBT movement and civil rights movement. Some of these traditions claim an ancient lineage, but to my knowledge none have academically proven a lineage beyond WWI.
I myself am a traditional Wiccan initiate who practices Hellenismos, or the reconstructed religion of ancient Greece.
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Your neurodiverse (Aspie) score: 159 of 200
Your neurotypical (non-autistic) score: 75 of 200
You are very likely neurodiverse (Aspie)