When something is proposed as a matter of Christian faith, reflective believers ask, quite legitimately: What exactly is the revealed datum? Where and how is it attested? How can things be as faith says they are? What logically follows from the truths of faith? People who try to answer these and similar questions in a methodical way are called theologians.
Oxford Dictionary of the Christian Church
Among the Greek Fathers it comes to have two specific references: it can denote either the doctrine of the Trinity (i.e., of God’s being, as opposed to his dealings with the created order), or it can mean prayer (as it is only in prayer that God is truly known). Later, in the West it came to mean the science of the Divinely revealed religious truths. Its theme is the Being and Nature of God and His creatures and the whole complex of the Divine dispensation from the Fall of Adam to the Redemption through Christ and its mediation to men by His Church, including the so-called natural truths of God, the soul, the moral law, etc., which are accessible to mere reason. Its purpose is the investigation of the contents of belief by means of reason enlightened by faith (fides quaerens intellectum) and the promotion of its deeper understanding. In the course of time theology has developed into several branches, among them dogmatic, historical, and practical theology. The methods of classification of the sub-disciplines, however, fluctuate in different theological systems.
Cardinal Avery Dulles
Avery Cardinal Dulles, “The Freedom of Theology,” First Things, May 2008, p. 19. Some excerpts:
When something is proposed as a matter of Christian faith, reflective believers ask, quite legitimately: What exactly is the revealed datum? Where and how is it attested? How can things be as faith says they are? What logically follows from the truths of faith? People who try to answer these and similar questions in a methodical way are called theologians.
The objection can be made that it is the theologians’ role to study current questions and that the magisterium, if it speaks at all, must follow the guidance of theologians. The historic experience of the Church, in my estimation, shows that theologians are often unable to resolve their own differences, still less to establish doctrine for the Church. They are, by training and temperament, suited to gather data, to ask questions, and to speculate, rather than to make doctrinal decisions for the Church. Some theologians regard doctrinal decisions as an unwelcome intrusion on their own freedom of inquiry. As scholars, theologians dwell in a somewhat rarified atmosphere, concocting new theories and interminably debating them. For all these reasons, the Church needs a living voice other than that of theologians to preserve continuity with the apostolic faith and to maintain communion throughout the Church. We may be grateful, then, that Christ has equipped the Church with a body of pastoral teachers, competent to decide what is to be preached and to set the limits of theological debate.
For fruitful relations between themselves and theologians, it is desirable for popes and bishops to be theologically educated. According to the present Code of Canon Law, every bishop ought to have a licentiate or doctorate in biblical studies, theology, or canon law, or at least be truly skilled in these disciplines. But the same canon requires that bishops be outstanding in strength of faith, moral probity, piety, zeal for souls, wisdom, prudence, and other human virtues and gifts needed for their office. Professional theologians do not necessarily make the best bishops. If they are raised to the episcopal office, they must learn to separate their theological positions, which are personal and private, from the doctrine of the Church, which it is their responsibility to promote. For good reasons, therefore, the Church generally selects its bishops from priests experienced in preaching, counseling, and active ministry who have, in addition, shown a capacity to delegate and to govern.
In their magisterial role, residential bishops have a primary responsibility to judge what should be preached and taught in their particular church at a particular time. Even popes and councils, speaking to and for the universal Church, do not escape the conditions of their own age and culture. The bulk of official teaching is correlated with particular historical contingencies but is not for that reason less authoritative. The magisterium has a pastoral mandate to direct the Church’s response to new challenges and opportunities. Prudential decisions of the magisterium, responding pastorally to particular crises, may lose their binding force under changed conditions, though the principles they embody may be permanently valid.
Although the functions of the magisterium and of the theologians are distinct, each group requires and profits from the work of the other. Theologians depend on the magisterium because the creeds and dogmas of the Church are constitutive for their own enterprise. Theology is a reflection on the faith of the Church as set forth in the canonical Scriptures and in the official statements of the Church’s belief. If the magisterium were not trustworthy, the foundations of theology, including even the canon of Scripture, would crumble. The more abundantly theology draws on the teaching of the magisterium, the richer, generally speaking, will it be. To ignore or dismiss magisterial teaching is to neglect resources that are at hand. It is possible, of course, to disagree with the magisterium on some point or other or to wish to nuance its declarations, but the first instinct of the theologian should be to accept and build on what is officially taught in the Church. It is a great benefit for theology to have a magisterium that is committed and qualified to safeguard the apostolic faith.