I just watched The Possession of Emily Rose. Although there was an attempt to portray both the natural and supernatural explanations for the events that led to the death of the title character, the presentation of those events may appear to favour the supernatural explanation. I liked the way it was done, as the supernatural was always presented through the eyes of one of the characters, but I suspect that this point would have been lost on people who are inclined to believe in the supernatural to begin with.
The interesting thing that came across to me is how the belief in the supernatural itself played into Emily Rose's possession. It is clear from the ubiquitous presence of Catholic iconography around the house that Emily Rose was primed from childhood for a strong conviction concerning the existence of spiritual agencies, demonic as well as divine. When she is struck by what appeared to me to resemble a night terror or sleep paralysis, she interprets this as a demonic attack. It seems likely in the course of the movie that she was afflicted with a form of epilepsy, but it is interesting to note that the terror of this original episode, even if it were a simple case of sleep paralysis, might have been sufficient to lead to the rest of the story.
As the movie progresses, many of the people who make contact with Emily Rose's story become convinced that they are being stalked by the powers of darkness. The priest on trial is the first, but soon the defending attorney is hearing things go bump in the night and interpreting chance occurences as signs. When a doctor who was present at the exorcism comes forward, it becomes clear that he too is convinced that the devil is after him. They have all apparently entered into a war with the devil, and the devil is working against them. Their only defense is in totems, signs, and portents.
Towards the end of her life, after an unsuccessful attempt at exorcism, Emily Rose writes to the priest to tell him that the Virgin Mary offered her an end to her suffering with a quick death, or the choice to continue in agony to prove to the world that God exists. Emily Rose chooses the heroic path, and dies a few weeks later, having refused all further attempts at exorcism. Her ordeal becomes an act of witnessing, to stand as proof to the world that the unseen world is real. Likewise, the priest and defending attorney also feel compelled to tell her story, to also give witness to the existence of the spirit world.
The movie tracks the transmission and fortification of a meme, and a particularly deadly one at that, possibly the most destructive parasitic meme known to humanity. In its more benign form, this meme is the belief in the spirit world, in disembodied intelligent agents who can affect the physical world and those in it. Those who hold this belief are carriers of a virus but manifest few or no symptoms. But there are a rare few, like Emily Rose, who come down with the full syndrome. They become possessed. The simple belief in evil spirits takes root and gives rise to an alternate personality.
The first stage of an exorcism is called the Pretense. During this phase, the exorcist and his assistants seek to tease out the demonic personality from the real personality, treating each differently as separate entities. In the exorcism proper, the exorcist then attempts to extract the name of the demon. The name, according to the lore of exorcism, is essential in controlling the demon. By the old laws of magic, having the name of a thing allows you to understand and control it (this is why the name Jehovah was never to be spoken.) But these two features of exorcism reveal another intent--not merely to draw the demon out, but to actually create the alternate personality. This is a dance of belief, an negotiation leading to the definition of the main character in a shared story. The name is appropriate to the character of the demon; it may be an historical demonic name, or a name indicative of its personality. But once fixed, everyone 'knows' who they're dealing with. The meme acquires a face and a name.
To be present at one of these affairs must be an overwhelming experience. Here a belief already firmly held is extended to its most extreme and absurd form. In the possessed, all the stops are pulled. Pain is silenced or ignored; as with people high on PCP, the absence of pain permits extraordinary feats of strength, because the possessed is unaware of damage done to bone and sinew which would ordinarily check exertion. We already know that hypnosis can be used for pain management. The absence of discomfort can help with some truly amazing facial and bodily contortions as well. It's easy to be an instant yoga master when you just don't care that your limbs are popping out of their sockets. The demonic construct, which shares the belief of all the participants that it will be able to jump clear of the body when it dies, doesn't really mind if the body is damaged. Knowledge rarely employed is drawn upon to create the illusion of supernatural cunning. This isn't all that hard--you just have to be cleverly obtuse. Read Foucault and you'll get the idea. And after a few days of screaming, everyone sounds like the cookie monster, just like the lead singer of most heavy metal bands.
What really gives the game away is that the demon is very naughty, but not really all that evil. It may scratch, bite, kick, swear, and make a mess, but if it were really intent on racking up a body count, it would sit quietly, play nice, and then slit everyone's throat while they were sleeping. This conforms to the account of hypnotised people resisting suggestions which call upon them to violate their ethical code. The naughtiness is another matter; they are, after all, possessed, and no one is going to believe in God if the demon looks fake. This is simply expected of them, and in the Pretense, it is made clear that they'd better perform.
The most convincing aspect, however, is the spectacle of self-destruction involved. But then, part and parcel of the faith is self-sacrifice and the mortification of the flesh. If the reward in the next life is directly proportional to the suffering in this one, then those who are demonically possessed are destined for great things. Christians have been beating themselves up for centuries, and most don't even have demons to blame for this. Auto-sado-masochism is, in my opinion, the very zenith of kink, but when you've been told all your life that everything that feels good is bad, your wiring will tend to get rather crossed. It's funny to say all this, but actually seeing it taken to the extremes present in exorcism would be a truly horrific and profound experience. We can see similar measures of self-annhilation at work in anorexia nervosa, the 'good girl's' disease, but even that pales by comparison. Murder, apparently, is a sin, unless the victim is yourself and you've chosen a spectacularly painful way to do it.
It is, however, still murder. Exorcism contributes to the belief structure that facilitates it, and is as blunt a therapy as performing brain surgery with a pickaxe while blindfolded. But so too does the belief in the afterlife, and contempt for the body. The main purpose of the phenomena of possession is to propogate the meme of supernatural agency. The devil's greatest trick was not, as the old saying goes, to convince the world that he didn't exist, but to convince the world that he did. It is hoped that by convincing people that the devil exists, they will believe in God. But a strong belief in the devil is faith in the power of evil. Jihadists murder civilians because they are convinced all of the West belongs to Shaitan. Nazi propoganda made devils of the Jews, greasing the slope to the Holocaust. The witch craze led to the torture and execution of thousands of innocent men and women. Religious wars have always been driven by the certainty that the enemy is in league with the devil. Giving up the belief in God may not be necessary, if we can just get people to give up their faith in the devil.
Still, the meme marches on. I'm not certain whether it was one of the fictionalized aspects of the story, but Emily Rose was convinced her ordeal would spread her beliefs to others. It worked, and for some people, through this movie, it may still be working.