<!-- @page { size: 8.5in 11in; margin: 0.79in } P { margin-bottom: 0.08in } --> ...I think the demon's target is not the possessed; it is us...the observers...I think the point is to make us despair; to reject our own humanity...to see us as ultimately bestial; as ultimately vile and putrescent; without dignity; ugly; unworthy. And there lies the heart of it, perhaps: in unworthiness. For I think belief in God is not a matter of reason at all; I think it is a matter of love; of accepting the possibility that God could love us. William Blatty, The Exorcist, pg 369.
(Blatty 369)
Humankind has always thought itself a little above nature in terms of its intellect, and this has led to an angel/animal duality where our socialized, civilized side is in a conflict with our instinctual, primitive side.
We are animals with an advanced conscience.
The Greeks described this as like driving a chariot with one horse representing instinct and emotion, and the other reason.
When we allow the instinctual side to take reign, our socialized side--the one that lauds reason and decorum over emotion and irrationality--feels guilty, and in separating our world, we put ourselves in opposition to the universe. We want to love ourselves; we want the universe to love us, and to be accepted. But the conflict is always there, since we cannot (as yet) separate our animal side from our angel side.
The Christian way of settling this is through atonement: believing that one is being forgiven by the ultimate reality, and thus loved.
Other cultures have other ways of settling this. Many involve accepting the animal side as being in harmony with the angel side (Yin and Yang, the Pentacle), and others involve reaching a level of equality with the universe (Enlightenment, Nirvana).
Blatty, William. The Exorcist. New York : Bantam Book, 1971.