Responsibility to the Inquisition varied with the grade of heresy, which was carefully classified by the theologians. Material heresy is error in a baptized person arising from ignorance and, if the ignorance is inculpable, it is scarce to be considered as true heresy deserving of punishment.[11] Formal or mixed heresy is voluntary and pertinacious error, pertinacity being adherence to what is known to be contrary to the teachings of the Church. This formal heresy is again distinguished into internal, or mental, and external. Internal, or mental, heresy is that which is secretly entertained and is not manifested by either word or act. External heresy is subdivided into occult and public. Occult external is that which is manifested by words or signs, either in secret or to one or two persons only--as though a man in the solitude of his chamber should say "There is no God," or should utter his thought in the presence of another. Public external is that which is manifested openly, either in public or to more than two persons.[12] The bearing of these distinctions on the work of the Inquisition will be apparent hereafter. [Sidenote: _EPISCOPAL JURISDICTION_] There was still another definition of even greater importance. Heresy was both a sin and a crime. As a sin it was subject to the _forum internum_, or forum of conscience; as a crime, to the _forum externum_ or judicial forum. A penitent in sacramental confession, admitting heretical belief, might receive sacramental absolution and be pardoned in the sight of God, but the crime, like that of murder or any other violation of human laws, would still remain to be punished in the judicial forum. We shall see that in the Inquisition the penitent, who confessed and repented and received absolution, was still subject to penalties ranging, according to circumstances, from slight penance to death. * * * * *