Arthur Miller, in his play "The Crucible," examines the hysteria which existed within the village of Salem, Massachusetts in 1692 (during the Salem Witch Trials). Many villagers were accused of witchcraft based up old and current feuds, personality conflicts, and uncertainty.
Sarah Good is a villager who does not live up to the village's expectations. She lives outside of the village limits (on the edge) and many believe her to be crazy. Given that this period of time warranted specific behaviors (reading the Bible and going to church), anyone not following the word of God, or going against the town's majority, was an easy target of hatred.
Eventually, Sarah Good is accused of witchcraft. To prevent her own hanging, Goody Good admits to practicing witchcraft. The only way an accused witch would be pardoned was through admitting to the crime or being found not guilty (which rarely happened). Therefore, only through admitting that she practiced witchcraft was Goody Good allowed to live.