In systematic theology there has always been the issue of how one explains the development of doctrine. If we think of theology as cognitive assent to timeless propositions excavated from Scripture, how do we explain the fact that the church’s theology seems to have developed, crystalized, changed, and even been corrected over time? The doctrine of the Trinity was gradually formulated through torrid debates climaxing in the councils of Nicea (325 AD) and Constantinople (381 AD), but even since then the doctrine of the Trinity has been refined by Augustinian and Cappodocian thinking, and even by the modern contributions of Karl Rahner and Karl Barth. The Reformation’s theology of the atonement and salvation was not entirely unprecedented, however, one must acknowledge that a forensic justification and penal substitutionary were at best peripheral in patristic sources and yet were made central to the schemes of the Reformers. Likewise, theologies of creation certainly had to be updated with the Copernican revolution, Newtonian science, and Einstein’s theory of general relativity, as were theological anthropologies after Darwin and the discovery of the human genome. In terms of ethics, the church has changed from once accepting the practice of slavery (even if it known to be less than ideal), to recognizing its inherent injustice and opposing it outright (now campaigning for the abolition of modern slavery). If theology was ever perfect, when was it? The Day of Pentecost (30 AD), when the Westminster Confession was written (1647), or with the Chicago Statement on Biblical Inerrancy (1979)?
The development of doctrine is an issue for evangelicals who acknowledge the formal and material authority of Scripture, and yet who also recognize the need for chastened, corrected, constructive, and contextualized theologies to emerge. At no point in the Christian tradition has theology ever been definitive, it has always developed and progressed. Theology is never frozen or finished, it is always “under construction” as the church struggles to know its own mind while it attends to Scripture, wrestles with tradition, observes nature, reflects on experience, and speaks within its local cultures. The doctrine of the Trinity and the ethics of slavery are exemplars of how doctrine and ethics can develop. As such, theological orthodoxy should not be identified with doctrinal mummification, naïve antiquarianism, curatorial Christianity, or ecclesial primitivism. While theology concerns itself with the quest for normativity – right belief, right worship, and right practice – it has always been provisional and contextual. When Vincent of Lérins defined the Catholic and Orthodox faith as “that faith which has been believed everywhere, always, by all,” it never meant that doctrines do not develop or come to diverse expression, only that development must be organic to the apostolic message and reach for catholic consensus. Vincent himself acknowledged the possibility of “progress in religion in the church of Christ” on the proviso that “the progress made must be according to its own type, that is, in accord with the same doctrine the same meaning, and the same judgment.” To tease that out, the theologies of Marcion and Arius were arguably marked by radical innovation rather than an organic outworking of the apostolic teaching. In contrast, Athanasius’ championing of the Father and Son as being homoousios (“sharing the same substance”) was using ontological language to simply affirm what Scripture said, that the Father and Son are equal, and represented an organic development within the tradition to bring clarity to the Father-Son relationship and to meet the challenge of the Arian option which confused the economy of grace and rendered the church’s worship as blasphemous. Proof that some change is often for the best.
In which case, theological development is a necessity given the evolving state of the world, its moral crises, the flux of its languages, new questions emerging, and the theological controversies that periodically arrive on the scene. In order to deal with this, the church must be, as the Reformers claimed, Semper Reformanda, “always reforming.” Similarly, the Puritan pastor John Robinson said, God always has new light shining upon his word. But this new light is not new revelation, not a contradiction of what has gone before, it constitutes a clarification and amplificiation to the apostolic faith. Development is about progress not a permutation, things doctrines newly said not newly devised doctrines, restated concepts not contempt for the past. Development is about rendering biblical judgments in the garb of newly contextualized expressive concepts. Thus, change should not be resisted, as much as be done in a way that is faithful to what has been received. To that end, the challenge is to determine which developments are organic and which are innovative ruptures (e.g., what do we make of developments like dispensationalism, covenant theology, the ordination of women, paedo-communion, congregational government, divorce and remarriage, mono-episcopacy, acceptance of homoeroticism, material views of the human body, gender neutral language for God, ecological ethics, etc.). The task of Christian theology is to determine precisely the legitimacy or illegitimacy of various developments.
 Rhyne R. Putman, In Defense of Doctrine: Evangelicalism, Theology, and Scripture (Minneapolis: Fortress, 2015), 327.
 Thomas G. Guarino, Vincent of Lérins and the Development of Christian Doctrine (Grand Rapids, MI: Baker, 2013), 16.
 Vincent, Commonitorium, 23.3.
 Vincent, Commonitorium, 23.1-3.
 David S. Yeago, “The New Testament and the Nicene Dogma: A Contribution to the Recovery of Theological Exegesis,” Pro Ecclesia 3 (1994): 160-61.
 Donald G. Bloesch, Theology of Word and Spirit: Truth and Method in Theology (Downers Grove, IL: InterVarsity Press, 2005), 125.
 Yeago, “The New Testament and the Nicene Dogma,” 162-64.
 Vanhoozer, Drama of Doctrine, 125.
 See discussion in William Webb, Slaves, Women, and Homosexuals: Exploring the Hermeneutics of Cultural Analysis (Downers Grove, IL: InterVarsity Press, 2001).