Why does reverend parris become upset at the thought that illness is a result of unnatural causes in crucible?

In _The Crucible_, Reverend Parris becomes upset at the thought that illness is a result of unnatural causes because it challenges his religious beliefs and authority. As the minister of Salem, Parris believes that all events, including illness, are part of God's plan and that the community should turn to prayer and faith for healing. The idea that sickness could be caused by witchcraft or other supernatural forces threatens his position as the spiritual leader of the town and suggests that there may be forces at work beyond his control. This challenges his authority and undermines the power of the church, which is why he becomes so vehemently opposed to the idea.