HERESY, in its primary meaning signifies an act of choice, whether good or bad (cf. LXX. in Gen. xlix. 5; Lev. xxii. 18, 21; Neh. xii. 40; I Macc. viii. 3o) ; it is the English equivalent of the Greek a ipeacs. From this arose its later meaning of personal choice of an opinion or belief, or personal adhesion to a group or party advocating certain principles of belief ; from this again it was used of the group or party as such, as a school or "sect." In Eusebius (Hist. x. 5) the Christian Church itself is described as the "most sacred heresy." But in the N.T. we see the word, acquiring the implication of disparagement or condemnation. It is applied to the Pharisees and Sadducees (Acts v. 17, xv. 5, xxvi. 5) and to Christianity itself by opponents (Acts xxiv. 14, xxviii. 22), with implied censure of a factious spirit. Specially noteworthy is its application to "divisions" due, not to matters of opinion, but to breaches of the law of love (Rom. xvi. 17; Gal. v. 20; I Cor. i. 1o; iii. 3,4; xi. 19) . In one of the latest books of the N.T. the word is used of doctrinal errors and their advocates (2 Peter ii. I, and Jude, 4, "false teachers," "sects of perdition") . In general, the apostolic writings show a vehement antagonism towards all teaching opposed to the gospel, whether the word "heresy" is used or not. This is explained by the character of the teachings or movements so attacked. They involved such a blend ing of the gospel with Jewish and Pagan elements as would have destroyed everything distinctive of it. Before illustrating the theological and ecclesiastical use of the word heresy in the history of Christianity, we must briefly examine its more general sig nificance.
From this point of view a "heresy" may be compared to a "paradox," in the sense of a proposition contrary to the body of belief on a given subject held in a particular country or a par ticular age, or even by most men, always and everywhere. And this fact serves to call attention to the other side of the case which we have stated. Such a proposition is not necessarily false because of its paradoxical or heretical character. Many times in the history of human thought a belief once heretical has be come a universally accepted truth, "sometimes a paradox, but now the time gives it proof" (Hamlet, iii., i. 115) : so Hobbes de scribed a paradox as "an opinion not yet generally received" (English Works, edit. Molesworth, v. 304). In every age of the world there have been established systems opposed from time to time by isolated and dissentient reformers (cf. De Morgan, Budg et of Paradoxes, 1872, p. 4, sqq.) . Such an established system has sometimes fallen slowly and gradually, upset by the rising influence of some one man or undermined by gradual change of opinion in the many. It must be admitted that an opinion being "generally received" implies a preoccupation of the ground which must hold good until sufficient reason is adduced against it. To this extent there is a presumption against anything "heretical"; the burden of proof lies with him who maintains it. Nevertheless, the history of science is partly the history of paradoxes becom ing commonplaces and heresies becoming orthodoxies, e.g., the motion of the earth, the possibility of the antipodes, the pressure of the atmosphere (as against the dogma "Nature abhors a vacuum"), the circulation of the blood, the facts of hypnotism, the electrical phenomena produced by Galvani's experiments— to mention only a few of the cases now utterly beyond the reach of controversy. Contemporary science is enlarging indefinitely its conception of natural possibility; and hitherto unknown and un suspected facts have emerged in regions of enquiry which might have been supposed exhaustively explored, e.g., the constituent gases of the atmosphere. "Such experiences indicate the need of a spirit of caution in those who may be tempted to condemn avenues of scientific enquiry as bound in advance to be unfruit ful. Yet it does not follow that the march of science is impeded by such premature judgments. Rather they may be regarded as sheep-dogs, which keep the scientific flock together in its progress to those fields of thought which for the moment offer the richest pasture" (H. A. L. Fisher, Orthodoxy, p. 37, 1922).
The influence of these controversies continued in the 3rd cen tury, when new divergent tendencies emerged. A revised Adop tianism, embodied in a more elaborate theology, was taught by Paul of Samosata and by Lucian at Antioch (see PAULICIANS). It spread widely and Arius was influenced by it. During the lat ter part of the 3rd and part of the 4th century, the movement said to have been founded by Mani, the Mesopotamian (see MANICHAEISM), at first sight looking like a revived Gnosticism, invaded the Church ; Augustine adopted it for a time, and its in fluence is probably found in some of the enthusiastic movements characteristic of the early mediaeval period (see below). Mani chaeism, however, was not a serious danger to the Church; and the controversies characteristic of the 4th century were those arising from the Adoptianist Christology as it spread in the East through Paul of Samosata and through Origen's doctrine of the subordination of Christ to the Father (see ORIGEN). The doc trinal struggle came to a head in the contest between the fol lowers of Arius and their opponents, afterwards led by Athanasius, at the Council of Nicaea in 325 (see ARIUS; ATHANASIUS). Arian ism became a heresy, but it found defenders down to modern times. The Nicene Council is a turning-point in the history of heresy. The earlier heresies (as indicated above) threatened to mingle with the gospel Jewish or pagan elements fatal to its es sence ; while many of the later heresies were differences in the interpretation of Christian truth which did not in the same way threaten the essence of Christianity. No vital interest of Chris tian truth justified the extravagant denunciations in which theo logical partisanship so recklessly and ruthlessly indulged. Again, in the ante-Nicene period only ecclesiastical penalties, such as reproof, deposition or excommunication, could be imposed; but in the post-Nicene the Lnion of Church an State transformed theological error into legal offence. This greatly embittered the Christological controversies which sprang from the Council of Nicaea (see NESTORIANS ; MONOPHYSITES ; MONOTHELITES).
From the end of the 4th century the emperors accepted the view that they were bound to use their secular power against heretics for the maintenance of orthodox doctrine.
The heresies of the middle ages were not matters of doctrine merely (however important), but were symptoms of spiritual movements, common to people of many lands, and in one way or another threatening the foundations of the Roman Catholic sys tem (see ALBIGENSES; BOGO:VIILS; CATHARS; WALDENSES). Such movements led to active ecclesiastical legislation against heresy; and several councils in the 12th and 13th centuries declared that the secular arm was bound to punish heretics. But it was main tained that heretics must in the first instance be brought before ecclesiastical courts, and this led to the erection of special Church courts with a procedure of their own (see INQUISITION). In evangelical Protestantism the older attitude survived in some of the earlier Protestant constitutions, where heresy is regarded as a crime punishable by the State. Logically, evangelical Protes tantism, which declines to force the consciences of its members and appeals only to Scripture for the confirmation of its doctrines, can only denounce erroneous doctrine as erroneous, and deal with them by persuasion and argument ; although this consideration does not prevent or invalidate disciplinary action in reference to ministers or lay members who defy the official standards of the organized Church to which they claim to belong.
BIBLIOGRAPHY.-For a general account see G. Cross, art. "Heresy" Bibliography.-For a general account see G. Cross, art. "Heresy" in Hastings, Encyclopaedia of Religion and Ethics, with references there given, and (from the Roman Catholic point of view) J. Wilhelm, art. "Heresy" in the Catholic Encyclopaedia; also A. Gordon, Heresy: its Ancient Wrongs and Modern Rights, Ig13 (with special reference to Gt. Britain) . On legal procedure, see Havet, L'heresie et le bras seculier au moyen age (r881) ; Richter-Wahl, Lehrbuch des Kirchenrechts (1886) ; Phillimore, Ecclesiastical Law. On the history, see Hilgenfeld, Ketzergeschichte des Urchristenthums (1884, specially valuable for sources) ; J. J. von Dolliuger, Beitrcrge zur Sektengeschichte des Mittelalters; and the standard histories of Dogma and of the Church. (S. H. M.)