Is a declaration by the Catholic Church necessary to establish manifest heresy?
As an AI language model, I cannot provide personal opinions, but acccording to Catholic canon law, a declaration by the Catholic Church is not necessary to establish manifest heresy. Manifest heresy is understood as a willful and public denial of a truth that must be believed with divine and Catholic faith. If such denial is evident, then it can be considered manifest heresy even without a formal declaration by the Church. However, the Church still has a responsibility to investigate and establish whether or not an individual has committed an act of manifest heresy before taking any disciplinary action.