The separation of church and state is a philosophical and jurisprudential concept for defining political distance in the relationship between religious organizations and the state. Conceptually, the term refers to the creation of a secular state (with or without legally explicit church-state separation) and to disestablishment, the changing of an existing, formal relationship between the church and the state. Although the concept is older, the exact phrase "separation of church and state" is derived from "wall of separation between church and state", a term coined by Thomas Jefferson. The concept was promoted by Enlightenment philosophers such as John Locke.
In a society, the degree of political separation between the church and the civil state is determined by the legal structures and prevalent legal views that define the proper relationship between organized religion and the state. The arm's length principle proposes a relationship wherein the two political entities interact as organizations each independent of the authority of the other. The strict application of the secular principle of laïcité is used in France, while secular societies such as Denmark and England maintain a form of constitutional recognition of an official state religion.
The philosophy of the separation of the church from the civil state parallels the philosophies of secularism, disestablishmentarianism, religious liberty, and religious pluralism. By way of these philosophies, the European states assumed some of the social roles of the church and the welfare state, a social shift that produced a culturally secular population and public sphere. In practice, church–state separation varies from total separation, mandated by the country's political constitution, as in India and Singapore, to a state religion, as in the Maldives.
History of the concept and term
Late antiquity
An important contributor to the discussion concerning the proper relationship between Church and state was St. Augustine, who in The City of God, Book XIX, Chapter 17, examined the ideal relationship between the "earthly city" and the "city of God". In this work, Augustine posited that major points of overlap were to be found between the "earthly city" and the "city of God", especially as people need to live together and get along on earth. Thus, Augustine held that it was the work of the "temporal city" to make it possible for a "heavenly city" to be established on earth.
Medieval Europe
For centuries, monarchs ruled by the idea of divine right. Sometimes this began to be used by a monarch to support the notion that the king ruled both his own kingdom and Church within its boundaries, a theory known as caesaropapism. On the other side was the Catholic doctrine that the Pope, as the Vicar of Christ on earth, should have the ultimate authority over the Church, and indirectly over the state, with the forged Donation of Constantine used to justify and assert the political authority of the papacy. This divine authority was explicitly contested by Kings, in the like of the, 1164, Constitutions of Clarendon, which asserted the supremacy of Royal courts over Clerical, and with Clergy subject to prosecution, as any other subject of the English Crown; or the 1215 Magna Carta that asserted the supremacy of Parliament and juries over the English Crown; both were condemned by the Vatican. Moreover, throughout the Middle Ages, the Pope claimed the right to depose the Catholic kings of Western Europe and tried to exercise it, sometimes successfully, eg. 1066, Harold Godwinson, sometimes not, e.g., in 1305 with Robert the Bruce of Scotland, and later Henry VIII of England and Henry III of Navarre. The Waldensians were a medieval sect that urged separation of church of state.
In the West the issue of the separation of church and state during the medieval period centered on monarchs who ruled in the secular sphere but encroached on the Church's rule of the spiritual sphere. This unresolved contradiction in ultimate control of the Church led to power struggles and crises of leadership, notably in the Investiture Controversy, which was resolved in the Concordat of Worms in 1122. By this concordat, the Emperor renounced the right to invest ecclesiastics with ring and crosier, the symbols of their spiritual power, and guaranteed election by the canons of cathedral or abbey and free consecration.