In contemplating Christian theology, it’s vital to distinguish synchronic from diachronic theology.
The Bible is not chiefly about theology (as in “systematic theology”), but about God’s revelation in history, centered in the Person of our Lord and Savior, Jesus Christ. However, the Bible does set forth theology (John’s account of Jesus’ teachings, Paul’s interpretation of Jesus’ redemptive work, etc.), and there can be no Christianity without it. When Jude exhorts his hearers to contend vigorously for the Faith once for all delivered to the saints (v. 3), he assumes a body of belief without which the Faith cannot exist.
Two Kinds of Theology
We may call this synchronic theology, theology as it was originally given to the apostles and recorded in God’s inspired Word, the Bible. It underwent slight development in the apostolic era as it was revealed to the Biblical writers; but when that age ended, and when that theology was later given permanent form in the text of the Scriptures, it became a fixed body of doctrine. It became Christianity’s deposit of Faith. This is synchronic theology, synchronic meaning that it is not subject to historical development. Once it has been solidified in the Bible, it becomes unchangeable.
However, godly men since the apostolic age have reflected on that Biblical theology. They have interpreted it, and they have drawn out its implications. We may call this diachronic theology, that is, theology as it has developed over time. This form of theology started even in the apostolic age, and parts of it were given universal, binding authority at the early church councils. This theology, inscribed in the Apostles, Nicene, and Athanasian Creeds, is orthodox Christian theology on which the vast majority of Christians agree — and have agreed. It is not inherently authoritative (only God and His Word are), but it is ecclesiastically authoritative.
The Diachronic Theology of the Reformation
Diachronic theology got a big push at the Reformation, because its churches wanted an extensive, binding interpretation of many doctrines of the Bible. It gave this interpretation in such “symbols,” or confessions of Faith, as the Augsburg Confession, the Westminster Confession, the London Baptist Confession, and the Thirty Nine Articles of the Church of England. In the medieval era, the church itself was vested with the authority to interpret the Bible — within the boundaries of the early ecumenical creeds, of course. The Reformation churches vested that authority (in principle, at least) in its confessions of Faith. The confessions, rather than the church, became the lens through which synchronic (Biblical) theology was interpreted.
Diachronic theology is desirable and, in case, inescapable. Why? For one thing. All of the Bible’s teachings on a certain topic (like the deity of Christ, baptism, predestination, faith, and so on) are not found in one place in the Bible. Whenever we systematize those teachings, we are practicing diachronic theology. For another thing, historical situations demand answers from the Bible that are not explicitly given in it. In the patristic church, the question arose as to how the infants of Christian parents should be included in the church, and how that inclusion should be formalized. This is how infant baptism gained almost universal acceptance. The Bible is not explicit about infant baptism, but the pressure of historical circumstances forced the church into a diachronic theology out of which the practice arose.
Roman Catholics, with their view of the church (their church) as the interpreter of the Bible, have sometimes blended synchronic and diachronic theology. The church’s reflection on the Bible (the Old and New testaments and the Apocrypha, the orthodox Trinity, the assumption of Mary, the infallibility of the Pope) has sometimes become as normative as the explicit teachings of the Bible. Protestants have created a greater distance between synchronic and diachronic theology. They want the Bible’s teachings to be normative, and they recognize human interpretations of the Bible to be reflective. This does not mean that they abandon the normative character of all diachronic theology (though some “radical reformers” have done this). The Protestants (at least the conservatives) hold the early ecumenical creeds to be normative but — and this is the key — only because these creeds teach what the Bible itself teaches. Synchronic theology always takes precedence over diachronic theology.
Normative and Reflective
The problem comes when synchronic theology becomes reflective, and diachronic theology becomes normative. The former is usually the problem of liberals, and the latter of conservatives.
Liberals do not believe the Bible and its teachings are normative. They see it as it best human authors’ reflection on God’s revelation to them. Because the Bible is not the inspired Word of God, its synchronic theology cannot be normative. In fact, sometimes it seems as though for liberals, synchronic theology (their own, of course) is normative, while the Bible’s theology is not. A flagrant example is Gary Conmstock’s book (published by the United Church of Christ) Gay Theology Without Apology. Here, diachronic theology has clearly supplanted synchronic theology.
I have already noted how that Roman Catholics have blended diachronic theology with synchronic theology. But Protestants, especially (and ironically) the most conservative Protestants, have sometimes done the same thing. This happens often among the “strict” confessionalists, those who permit no deviation from (or questioning of) their confessions of faith. Confessions of faith are simply examples of diachronic theology. When they are held to be above revision and amendment, they supplant the theology of the Bible.
Theology and History
A main goal of those committed to synchronic theology is to illumine the historical circumstances under which that theology arose. In other words, they try to understand the Bible and its message in its original historical circumstances. This is the task of historical criticism and grammatical-historical interpretation. When conservative Protestants oppose these tasks by deferring only to their confessions, they are denying the role of the normative character of diachronic theology. The Bible arose in particular history and a particular time to a particular people. Theologians call this the “scandal of particularity.” If we try to bypass the Bible’s history in ascertaining its meaning, and in deferring to later confessions of faith, we will not only hazard misunderstanding the Bible’s message; we will also undercut our faith’s very ground, which is (first-century) historical to the core.
Investigations into the Bible’s meaning in its historical circumstances are often met with assaults from conservative Protestants. These investigations are sometimes good, sometimes bad, but they are necessary. If we say that we do not want to learn more about the Bible’s message from those who investigate the history in which it emerged, we are really saying that the Bible is not ultimately authoritative. If we assert that a greater grasp of the Bible could never cause us to amend our confessions, we, like many Roman Catholics, merge diachronic theology into synchronic theology.
Diachronic theology, particularly orthodox, ecumenical theology, is ecclesiastically normative. Synchronic theology, the theology of the Bible, is ultimately authoritative.
If we really believe the Bible, we must never jettison diachronic theology, but we must always subordinate it to synchronic theology.