We can forget psychology and physiology, it's all the demons. If the Christian is willing to back into the "medical symptoms are the effects of the demon" corner, there's no real argument to be had. There's no argument because when someone is willing to concede any hope of evidence in favor of unfounded claims of causality, there's no way to make any progress.
People tried blaming everything we didn't understand or like on demons, it set science back and cost thousands of innocent lives. That people would take this dark-ages mentality into the 21st century disgusts me. The outright rejection of science in favor of superstition is so terribly harmful in so very many ways. There should never be a conflict here, yet the majority of America is still in the dark ages.
Anything which is beyond testing and observation should immediately raise a flag of warning. This includes all things spiritual. It's a shame that so many theists are advocates of the unfalsifiable hypothesis, it greatly inhibits my ability to learn from and talk to them.
The same Christian who went off on the devil thing is a conspiracy theorist (go figure), but oddly enough he also thinks governments are incompetent. The two are mutually exclusive. To plan a conspiracy and have almost no people know about it, a person or group must be incredibly prepared, organized and intelligent. An incompetent person or group would never manage to pull off such an elaborate plan.
At any rate, he submits on a regular basis the One-World-Government idea*. He says it's forming now, and that the devil is behind it. There are so many reasons why this is improbable, here are a few;
- So many governments don't like each other and couldn't merge peacefully.
- Many people would protest the idea and anarchy wouldn't be a ridiculous assumption.
- Religions of all colors which make up almost all of the world wouldn't let it happen.
- There are no real advantages to it.
Next, he decried Wicca as Satanism. He wasn't talking about the mainstream Satanism either, more the "Kill cute puppies, small children and anyone who annoys you" version, or put more simply, the bastardized Christian version of Satanism. Wicca has a karma system...On steroids. The law of three as it is called states that any energy one puts out into the world will come back threefold to bite them in the ass. Wicca has a requirement for the respect of free will and offers cosmic punishment for those who disregard free will. The semi-famous Wiccan's creed "An ye harm none do what ye will" shows the awful, evil, violent nature of Wicca, except oh wait IT'S ALL BUT THE DAMNED GOLDEN RULE!
I mentioned Satanism in the past paragraph. The version I stated was as I said, bastardized. Satanism is essentially religious libertarianism. There are rules of Satanism saying that harming animals and children is wrong. I'd go further to say that harming anyone who isn't trying to harm anyone is wrong in most cases, but it's still not the kitten-blood-drinking, bonfire-lighting, demon-summoning ideology which people assume. Most of the cases which the author of Extreme Evil: Kids Killing Kids gives in his promotional video are high-school related, naturally. The problem is the factor of rebellion in high school, an angry child will reach for what they perceive to be the darkest thing out there to impress their peers and annoy authority. Some times there's more to it, but to entirely discount rebellion as a cause of this is disingenuous.
*I don't grace it with calling it a theory, even as far as conspiracy theories go.