The first decades of the 20th century were traumatic for American Protestantism because for half a century the churches had gradually divided into conservative (fundamentalist) and liberal (modernist) wings. The liberal churches accepted Darwinian evolution and integrated it into their belief system as "God's way of doing things." They envisioned religion as evolving from the primitive to the complex, with Christianity being the most evolved religion. The Bible was viewed not as a supernatural production, but as a collection of myths and primitive understandings. At the very center of presuppositions behind modernism was the authority of reason and the findings of science. What was not reasonable or scientific was discarded, such as the virgin birth, resurrection and Second Advent of Jesus, miracles, and substitutionary atonement. Jesus was an example of what human being could become. They promoted the essential goodness of human nature, that sin is not rebellion but ignorance correctable by education and social reform, and that the kingdom of God was brought through the ceaseless process of evolution.