The Enlightenment had a profound impact on the Church. Its impact is felt today. It is impossible to cover each and every nuance in a blog format. What I want to do is focus the overall impact it has had on Protestantism.
The 16th Century Reformation came in response to a Roman Catholic Church that had become corrupt and ineffectual. As Luther, Calvin and other reformers emerged from the struggles of the day, they questioned the emphasis that had been placed on Church tradition for past centuries. They wanted to ground authority in something else? Sola Scriptura, scripture only.
It didn’t take long to realize that consensus on scriptural teaching was an elusive effort. What would be the core determinative principals that would inform how scripture is understood? What was foundational to the Christian living?
As the Enlightenment flourished in the in the 18th Century, there became a growing dichotomy between natural religion and revealed religion. The first related to religion that could be demonstrated by reason and the latter to doctrines taught by various religious factions. Hostility increased toward revealed religion and lead to deism and ultimately to an impasse. The two choices left were to be to abandon reason and accept the doctrines of the Church or embrace skeptical rationalism.
The 19th Century saw yet another twist develop as theologians began looking for a way through the impasse. Some theologians worked to identify religious experience that was common to all humanity. They postulated that there is a God consciousness in each of us. By tapping into that consciousness we gain insight and doctrine emerges out of those insights. Jesus was the greatest example of the path toward the God consciousness. The human mind in search of foundational experience became exalted over the scripture. Scripture was demythologized and reinterpreted to meet what ever God consciousness direction theologians were going, always in search of the foundational reality. This became the liberal trajectory over the past two centuries.
The conservative theologians chose to respond to the impasse differently. The fully embraced rationalism and determined to demonstrate the truth of scripture by reason . The project became one of creating the unassailably logical Bible. Theology become less the study of God and more the science of doctrine. Theologians labored to identify the key propositions that would rationnally explain the whole Bible and incorporate any anomalies. The inerrant Bible would then offer a perfect "system" for addressing all issues.
As the Twentieth Century unfolded, the liberal wing of Christianity was in its glory. The Christian Century Magazine started in 1900 as a witness to the fact that this was the century that would usher in the "Kingdom of God." The exercise of science would be one of the primary means for creating this new age. Conservatives, on the other hand, rejected the “godless” science of the liberals, for their “holy” science that reinforced the inerrancy of scripture. They too had the optimism that they could prevail with their rational inerrancy and usher in a new age.
As it turned out, the conservative agenda lost the public relations war three decades into the century. The conservative agenda became increasingly gloomy and isolationist with regard to culture. The Great Depression sandwiched between two world wars disillusioned many liberal Christians and eventually led to the “God is Dead” movement in the 1960s. While the liberal movement did carry some currency in the civil rights arena for a time, it soon became a fragmented mix of various ideology driven theologies (e.g. liberation, feminist, etc.) There was a re-engagement with the culture by the more conservative Christian wing beginning in the late 1970s but ultimately it showed little influence in moving the culture to a Christian mindset. It too has been fading of late.
The irony is that both liberal and conservative Christians neutered the transformative power of the Word of God, and thereby the Church, with their foundational approaches. The liberals reduced scripture to little more than supplemental material on the way to discovering God. So complex and nuanced did scripture become, that only a specialized class of Christians (scholars and clergy) could be trusted with appropriate interpretations. Meanwhile, conservatives turned the Bible into a complex collection of data that could only be deciphered by systematic theologies and/or clergy who could help you link all the pieces together into an approved, rationally coherent, system.
In either case, why read the scripture for yourself? What transformative power can scripture have when it is merely a collection of highly complex ancient documents that "might" point you to a path, or it is just a collection of theological data to be used in a theological erector set? That is where we are at today.
(I highly recommend “Beyond Foundationalism,” by Grenz and Frank on this topic.)