Christian Heresies

Jesus himself warned his followers to 'beware of false prophets' (Matthew 7, 15; see also Matthew 24,3-28, and Mark 13, 22); and the Christian Church has always been concerned to protect its members from falling into error in matters of religious belief. Even before Christianity became widespread in the Roman Empire, let alone its official religion, Christian thinkers sought to identify and refute what they regarded as false doctrine, i.e., heresy, and some of the Early Church Fathers wrote works exposing what they took to be heresies - most conspicuously, St. Irenaeus (died c202 CE), bishop of Lugdunum (modern Lyons in France), in his Adversus haereses (Against Heresies, c180), and Tertullian (Quintus Septimius Florens Tertullianus) (?160-?225), a Carthaginian lay Christian, in his De praescriptione haereticorum (On the Prescription of Heretics, c200).

But who should decide what is a heresy? And how should they decide the issue? It was Irenaeus' answers to these questions which largely determined the practice of the Christian Church. He argued that disagreements about doctrine within a particular locality were to be settled by the head of the church (i.e., the bishop) within that locality, and that it was for councils (i.e., meetings of bishops) to determine what was true and what was false in religious matters. (He also maintained that precedence over the other bishops should be accorded to the bishop of Rome, as the successor of St. Peter, the apostle appointed by Jesus as head of his church, and the first bishop of Rome.) Irenaeus argued further that any doctrine that conflicted with the teaching of Jesus must be false and rejected as a heresy. However, by the end of the second century many different accounts of Jesus' teaching, i.e., many different Gospels, were current, and it was therefore necessary for Irenaeus to decide which accounts were genuine, and which spurious. He proposed that an account should be regarded as authentic, and form part of the scriptural canon, only if its author could be shown to have been taught by Jesus himself or taught by someone whom Jesus had taught, and so on: in other words, he envisaged the true faith as having been handed down from teacher to disciple in an unbroken line, and assumed that the truth of a doctrine was guaranteed by its place in the tradition. (It is Irenaeus who is primarily responsible for the contents of the New Testament as we know it today.)

In the fourth century, after the conversion of the emperor Constantine I in 312, Christianity became widespread in the Roman Empire and began to acquire social and political functions, e.g., as one of the elements which served to unify the Empire. In these circumstances the need for uniformity of belief became more pressing - if only to avoid religious conflict which could threaten the Empire's stability. And once Christianity became the official religion of the Roman Empire at the end of the fourth century, clarity of doctrine became essential: if individuals were to be subject to legal punishment for not holding the correct beliefs - and the penalty for heresy could sometimes be death - it was vital that what the correct beliefs were should be clear. It was during the fourth century that the first ecumenical councils (i.e., 'worldwide' meetings of bishops) were held to resolve disputed points of doctrine, to promulgate as dogma beliefs found to be acceptable, to condemn as heresy beliefs found to be unacceptable, and to formulate creeds, i.e., authoritative statements of the set of beliefs to which Christians were expected to assent. The first ecumenical council, attended by 300 bishops and presided over by the emperor Constantine himself, was held at Nicaea, a city in northwest Asia Minor, in 325: it condemned Arianism, i.e., the teaching of Arius, as heretical and formulated the Nicene Creed.

Central to Christianity is the belief that Jesus was both the son of God and lived on earth as a human being, the orthodox interpretation of this belief being that Jesus had two natures and was both fully divine and fully human. Many, though not all, of the earliest heresies involve alternative interpretations, or even the denial, of this central Christian belief (see Arianism, Monophysitism, Nestorianism, Docetism, and Monothelitism). Other heresies relate to other elements of Christianity: Pelagianism, for example, concerns the extent to which we have free will and can be responsible for our salvation; while Gnosticism conflicts with orthodoxy on a number of issues, not least on the nature of the sources of truth in religious matters.