heresy

heresy. The formal denial or doubt of any defined doctrine of the Catholic faith. From early days the Church claimed teaching authority and consequently condemned heresy. The need to rebut heresy has sometimes stimulated the formulation of orthodox Christian doctrine.

In the early centuries heresy was mainly a matter of erroneous attempts to understand the nature of the Person of Christ, of the Trinity, or both. After the Church had become a structured and wealthy institution, many of the heretical movements were inspired by a desire to return to what was seen as the simplicity of the apostolic Church; they often came to reject the Sacraments as well as other institutions of the Church. The Inquisition was established to secure the conversion of heretics, and punished the obdurate.

According to RC canon law, heresy is defined as the obstinate denial or doubt, after Baptism, of a truth ‘which must be believed with divine and catholic faith’. This ‘formal heresy’ is a grave sin involving automatic excommunication. ‘Material heresy’, the holding of heretical doctrines ‘in good faith’, e.g. by those brought up in heretical surroundings, constitutes neither crime nor sin.