Those alive when the twentieth century began lived in a world that had been and still was experiencing unprecedented change. Longstanding empires had fallen. Others were reaching the height of their power as colonialism was at its peak. The wars caused by all of these events seemed never-ending. Additionally, the Second Industrial Revolution was creating massive social and economic changes as people fled the farms and filled the cities. Philosophically, the academy was still coming to grips with the questions of authority associated with the rise of modernity. Little did anyone then know, however, that the changes they had already witnessed would be almost nothing compared to what the twentieth century would bring.

Doctrinal Shifts in Europe and America

Since the beginning of the Enlightenment, questions of authority had remained at the forefront of philosophical and theological thinking. The authority of Scripture and/or the church was no longer taken for granted by most, but what was the alternative? Many Enlightenment thinkers had placed human reason in that exalted role, but others, such as those influenced by Romanticism, reacted against this. Christian theologians were forced to answer as well. In the nineteenth century, the father of German liberalism, Friedrich Schleiermacher, proposed inward religious feeling as his authority. Several prominent Anglicans attempted to find authority in early Christian history, creating the Oxford Movement. The Roman Catholic Church established the dogma of papal infallibility at the First Vatican Council (1869–70). Yet, in the midst of all this, there were still many, such as the Reformed theologians at Princeton Theological Seminary, who continued to defend the authority of the Bible.

As the twentieth century began, this dynamic continued. German liberalism continued to develop and to attempt to adapt to modern ways of thought. Adolf von Harnack, for example, published his What Is Christianity? in 1901, arguing that the inner truth of Christianity remained firm despite the fact that its external doctrinal form had been undergoing change since the first century. At the same time, the German History of Religions School was coming into its own with its claims that Christianity was a syncretistic combination of Jewish thought, mystery religions, and Stoic philosophy. The crisis in the cities caused by massive urbanization led to the rise of the social gospel under the leadership of theologians such as Walter Rauschenbusch. This Protestant liberalism would not remain unchallenged, however. After World War I, a number of German theologians, including Karl Barth, Emil Brunner, and Rudolf Bultmann, reacted against liberal theology, developing what would come to be known as dialectical theology. These men differed with German liberalism primarily on the relationship of history and faith, but the differences among them would ultimately lead each of them in different directions. Bultmann would develop his theology along the lines of existential philosophy and would have an enormous influence especially in the middle decades of the twentieth century, but the most influential theologian among the dialectical theologians would prove to be Karl Barth, whose Neoorthodoxy continues to influence theologians of all stripes to this very day.