Who is Rev. John Hale, and why does he come to Salem?

Reverend John Hale is a scholar from Beverly, Reverend Hale comes to Salem on Reverend Parris' request to investigate supernatural causes for Betty Parris' suspicious illness and thus instigates the rumors of witchcraft. Hale approaches the situation precisely and intellectually, believing that he can define the supernatural in definitive terms. Despite his early enthusiasm for discerning the presence of witchcraft in Salem, Hale soon grows disillusioned with the witchcraft accusations that abound and defends Proctor when he challenges Abigail. Hale does this out of guilt, for he fears that he may have caused the execution of innocent persons.