I know to a certain extent what the beliefs practices are, on top of at least a few of the members being rather bad at reading, but I’ll put that to the side for now. Whatever the doctrines of Wicca are, what’s their basis. I mean, Islam is based in the Qar’an, which is supposedly infallible. It’s an argument, perhaps a circular one, but it’s there. What evidence is there for Wiccan beliefs being true?
Our teachings originated with Gerald Gardner and continue to evolve with practice and communication between Wiccans. We do not have Scripture. We do not have any documents we consider infalliable, and I doubt you’d find any Wiccan who would claim that Gardner was perfect and his teachings unquestionable. That’s contrary to our beliefs.
There is a truth out there. Religious people seek that truth. Wiccans embrace Wicca because what it teaches makes intellectual sense to us, because it reflects our real-world experiences, and because the we find the rituals and practices to result in further understanding of the gods. Esoteric religions do not teach the truth so much as suggest paths to it. “Evidence” is what each of us has personally experienced. Those experiences will differ from Wiccan to Wiccan, and we generally do not expect anyone else to believe in Wicca just because we’ve had experiences.