but how would I distinguish a pagan from an atheist?The latter neither believe in, nor worship, any higher or supernatural power. The former seem to place an inordinate amount of faith into such things as trees and rocks.
"Pagan" is a catch-all term for a set of modern religions that do not worship the usual Christian/Judaic/Muslim deity. Pagans range from Wiccans and those who follow Wiccanesque ideals, to neo-Druids, to cultural reconstructionists (Egyptian, Greek, Roman, Celtic, Norse.) Some pagans are monotheistic but worship a single goddess. Some are polytheistic and believe in entire pantheons. Some (like Wiccans) are duotheistic and believe there is a god and a goddess and all deities of every culture are aspects of these two. Some are also animistic, meaning they believe there is spirit in the natural world. Not all are animistic though. Pagans are NOT Satanists. I'd say 95% of pagans don't even acknowledge Satan's existance, let alone think about worshipping him.
Don't worry, Freepers, pagans aren't a threat. I can't think of a single pagan sect that actively proselytizes or recruits. They mostly want to be left alone. I know, because I am one of them.