List of heresies in the Catholic Church

In its vision of heresy, the Catholic Church makes a distinction between material and formal heresy. Material heresy means in effect "holding erroneous doctrines through no fault of one's own" due to inculpable ignorance and "is neither a crime nor a sin" since the individual has made the error in good faith.^[1] Formal heresy is "the wilful and persistent adherence to an error in matters of faith" on the part of a baptised person. As such it is a grave sin and involves ipso facto excommunication; a Catholic that embraces a formal heresy is considered to have automatically separated his or her soul from the Catholic Church. Here "matters of faith" means dogmas which have been proposed by the infallible magisterium of the Church^[2] and, in addition to this intellectual error, "pertinacity in the will" in maintaining it in opposition to the teaching of the Church must be present.^[3]

Heresy has been a concern in Christian communities at least since the writing of the Second Epistle of Peter: "Even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them" (2 Peter 2:1). In the first two or three centuries of the early Church, heresy and schism were not clearly distinguished. A similar overlapping occurred in medieval scholasticism. Heresy is understood today to mean the denial of revealed truth as taught by the Church.^[1] Nineteenth-century theologian Friedrich Schleiermacher defined it as "that which preserved the appearance of Christianity, and yet contradicted its essence".^[4] This article contains the movements and denominations which have been declared as heresy by the Catholic Church.

The following listing contains those opinions which were either explicitly condemned by Chalcedonian Christianity before 1054 or are of later origin but similar. Details of some modern opinions deemed to be heretical by the Catholic Church are listed in an appendix. All lists are in alphabetical order.