Everyone has a belief system, even if it’s shunning what they identify as belief systems.
The core principle behind exorcism is not unlike an animal’s territorial behavior. Some species can tolerate the presence of other species in their territory fairly well, while others are much more aggressive and defensive against any rivals. This is why early exorcists would come to have a whole roster of different kinds of spirits categorized according to their behavior. It was sort of a guide for what was a proper course of action when faced with any specific kind of spiritual presence. These days, most people would try to drive off an angel, forgetting that even angels were originally seen as frightening presences. Originally, they would avoid trying to drive off angels at all costs as it was more or less seen as sin, but moving on…
Every culture recognized a compact of sorts between spirits and humanity, from the Chinese mandate of heaven, to the Egyptian concept of ma’at, to the spiritual relationships and taboos held by the Native Americans and the Polynesian Islanders. Some set of rules has existed everywhere, and the exorcist was basically a person well versed in the rules as well as other things, and acted as a sort of spiritual police. From the Gypsie lore regarding left handed men and children born with a cowl (which resembles a funeral shroud by the way, a skin that covered their face or eyes), to the concept of divine intervention of the extended tribal ranking in shamanic cultures.
There has always been ways of dealing with the spiritual criminal, if you will, but no single method was seen as universally effective. Placation ceremonies worked with some spirits, like those of offended ancestors, but not others, like dealing with angry elementals or elder spirits that previously inhabited recently settled land.
Any specific questions about exorcism? It’s really a broad practice.
Can anyone perform an exorcism? With proper knowledge and personal power, yes.
Is there a real danger to the exorcist? Not in the movie sense, no.
Say I notice a disturbance occurring in a community, how would I start? Depending on the spirit you are dealing with, there are circumstances where you would have to deal with it much like you might deal with a belligerent human being. The spirits argument is as valid as the human. In other circumstances, the spirit is causing a greater disturbance than just the human community, and the land itself will lend aid if you call on it.
So it is a lot like dealing with any human, you have to decide if diplomacy or intimidation is warranted? Yes, and sometimes even literal force. A medium can lead a spirit to see reason. This is why exorcism was often just the shaman acting as spirit guide for the spirit.
It’s good to have backup. You wouldn’t try and handle a violent person by yourself. Also true. Some spirits have genuinely inappropriate motivations.
Your thoughts are welcome. Be well friends.