The Illinois Supreme Court agreed to hear an appeal from a former Catholic school principal who is challenging a common law doctrine, which allows courts to abstain from weighing in on certain religious matters, as justification for her firing.Mary Rehfield v. Diocese of Joliet is one of 12 appeals, seven criminal and five civil, the justices accepted. In the court’s March 25 order, the justices denied 51 civil appeals and 92 criminal appeals.Rehfield sued the diocese upon her firing as principal of St. Raphael …