theology, in Christianity, the systematic study of the nature of God and God's relationship with humanity and with the world. Although other religions may be said to have theologies, this is a matter of controversy within, for instance, Judaism, which holds that God is unknowable. This article will therefore confine itself to Christian theology.

The development of theology in Christendom arose from the need for educated Christians of the ancient world to express their ideas in terminology familiar in current thought. Hence arose the close relation of Christian theology with Greek philosophy formulated by the Greek and Latin Fathers of the Church. St. Augustine, a Latin Father and one of the greatest theologians, introduced and standardized in his writings teachings that became central to Christian theology. Augustine's influence was paralleled in the East by that of Origen.

The great theological problems of the early church involved the relationship of the first and second persons of the Christian Trinity, the relationship of the divine and human in Jesus, and the relationship between God and humanity. One important struggle was over Arianism, the heresy that denied the true divinity of Jesus. The nature of grace was also debated during the Middle Ages and the Protestant Reformation; the heretical Pelagians (see Pelagianism) contended that a human being has the ability to take the first steps necessary toward salvation apart from divine grace. Augustine insisted, against the Pelagians, that humanity is totally dependent on grace for salvation.

Scholastic theology (see scholasticism) sought to illuminate matters of religious faith through intellectual understanding. Scholastic theologians such as Thomas Aquinas attempted to reconcile seeming contradictions in revealed truths by presenting a doctrine with supporting argument, contradicting argument, and a solution. Aquinas' Summa Theologica is often regarded as the greatest work of Scholasticism. Scholastics differentiated carefully between theology and philosophy by confining theology to the field of the systematization and investigation of revealed truths; in this distinction philosophy is to proceed always from reason and does not investigate the truths that transcend reason. The distinction is maintained explicitly by Roman Catholic thinkers and implicitly by conservative Protestants. According to this differentiation Calvinism and Lutheranism are theologies, not philosophies.

As a result of the 18th-century Enlightenment, especially the work of Immanuel Kant, a new rational theology arose in the 19th cent. This must be carefully distinguished from the "rationalism" of scholasticism, because 19th-century rational theology assumes as axiomatic the ability of reason to criticize adequately every truth. The theological school of Tübingen was the center for the extreme "rationalistic theologians," and there the "higher criticism" of the Bible, which revolutionized much of Protestant thought, was brought to its first fruition. The most profound of 19th-century Protestant German theologians, and perhaps the most influential of the new rationalists, was Friedrich Schleiermacher. The new rationalistic theology developed very rapidly, and hardly any two theologians of it agree in detail; there are various systems of modernism.

In the 20th cent. the Protestant neoorthodoxy movement emerged in Europe and America. It owed much to the theology of Karl Barth and Reinhold Niebuhr. The movement, which accepted the methods and findings of modern biblical criticism, interpreted religion as only one aspect of contemporary life and emphasized faith and revelation as divine gifts. Among Roman Catholics in the 20th cent., liberation theology, which originated in Latin America, has emphasized the importance of fighting oppression and aiding the poor through active roles in political affairs; since the 1980s it has been strongly criticized by the church hierarchy. Under Pope John Paul II, the Roman Catholic Church strongly reasserted its control over the teaching of theology by Catholic theologians, removing official sanction from Hans Küng and others who deviated from church doctrine.

liberation theology, belief that the Christian Gospel demands "a preferential option for the poor," and that the church should be involved in the struggle for economic and political justice in the contemporary world—particularly in the Third World. Dating to the Second Vatican Council (1962-65) and the Second Latin American Bishops Conference, held in Medellin, Colombia (1968), the movement brought poor people together in comunidades de base, or Christian-based communities, to study the Bible and to fight for social justice. Since the 1980s, the church hierarchy has criticized liberation theology and its advocates, accusing them of wrongly supporting violent revolution and Marxist class struggle.

Study of the nature of God and the relationship of the human and divine. The term was first used in the works of Plato and other Greek philosophers to refer to the teaching of myth, but the discipline expanded within Christianity and has found application in all theistic religions (see theism). It examines doctrines concerning such subjects as sin, faith, and grace and considers the terms of God's covenant with humankind in matters such as salvation and eschatology. Theology typically takes for granted the authority of a religious teacher or the validity of a religious experience. It is distinguished from philosophy in being concerned with justifying and explicating a faith, rather than questioning the underlying assumptions of such faith, but it often employs quasi-philosophical methods.

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Spiritual quest for union with the divine. Forms of mysticism are found in all major religions. Hinduism, with its goal of absorption of the soul in the All, is inherently predisposed to mystical experience. Buddhism emphasizes meditation as a means of moving toward nirvana. In Islam, Sufism employs metaphors of intoxication and of the love between bride and bridegroom to express the desire for union with the divine. In Judaism, the foundations of mysticism were laid in the visions of the biblical prophets and were later developed in the Kabbala and in Hasidism. Mysticism has appeared intermittently in Christianity, notably in the writings of St. Augustine and St. Teresa of Àvila, and in the works of Meister Eckhart and his 14th-century successors.

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Roman Catholic movement that originated in the late 20th century in Latin America and seeks to express religious faith by helping the poor and working for political and social change. It began in 1968, when bishops attending the Latin American Bishops' Conference in Medellín, Colom., affirmed the rights of the poor and asserted that industrialized nations were enriching themselves at the expense of the Third World. The movement's central text, A Theology of Liberation (1971), was written by the Peruvian priest Gustavo Gutiérrez (b. 1928). Liberation theologians have sometimes been criticized as purveyors of Marxism, and the Vatican has sought to curb their influence by appointing more conservative prelates.

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School of religious thought characterized by concern with inner motivation as opposed to external controls. It was set in motion in the 17th century by René Descartes, who expressed faith in human reason, and it was influenced by such philosophers as Benedict de Spinoza, G. W. Leibniz, and John Locke. Its second stage, which coincided with the Romantic movement of the late 18th and 19th century, was marked by an appreciation of individual creativity, expressed in the writings of philosophers such as Jean-Jacques Rousseau and Immanuel Kant as well as of the theologian Friedrich Schleiermacher. The third stage, from the mid-19th century through the 1920s, emphasized the idea of progress. Stimulated by the Industrial Revolution and by Charles Darwin's Origin of Species (1859), thinkers such as T. H. Huxley and Herbert Spencer in England and William James and John Dewey in the U.S. focused on the psychological study of religious experience, the sociological study of religious institutions, and philosophical inquiry into religious values.

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Any of several movements that attempt to revive the polytheistic religions of Europe and the Middle East. Largely a product of the 1960s, contemporary Neo-Paganism has flourished particularly in the U.S., Britain, and Scandinavia. Its adherents often have deep ecological concerns and an attachment to nature; many worship an earth-mother goddess and center their rituals on the change of the seasons. Since the late 1970s, Neo-Paganism has also attracted feminists open to female personifications of the deity. Major Neo-Pagan groups include the Church of All Worlds, Feraferia, Pagan Way, the Reformed Druids of North America, the Church of the Eternal Source, and the Viking Brotherhood. Seealso Wicca.

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