At the beginning of the Enlightenment, the Genesis record was considered factual. Living creatures existed today pretty much as they had when they were created a few thousand years earlier. Science was still influenced by Thomas Aquinas who believed that discovery of a purpose for a given object or phenomena was an intergral part of studying he physical world. Several things were about to change.
David Hume (1711-1776) was responsible for one of the most important changes toward modern science. He believed it was inappropriate to attribute purpose to anything that could be studied by the scientific method. This challenged the religious schema of science and opened up the possibility of natural selection and naturalism
One of the most important books of the early 19th Century was William Paley’s “Natural Theology,” published in 1802. Paley’s study made the case that we can learn about God by studying the natural world. Part of his thesis was the adaptation of various species depending on God’s purposes.
During 17 and 18th Century, biologist were discovering species at an overwhelming rate. Taxonomies were constantly changing as scientists sought to make sense of the new data. Even so, fixity of species remained the assumption of the day. When Zoologist Jean-Baptiste Antoine de Monte, Chevalier de Lamarck, published his “Zoological Philosophy,” in 1809, he made the case that there was a continual drive by life toward complexity, improvement and progress, thus challenging the notion of fixity. One scientist who shared this opposition to fixity was Erasmus Darwin, grandfather of Charles Darwin.
At the end of the 18th Century, and especially in the early 19th Century, a number of geologist (many of them clergy) were coming to the conclusion that the Earth was significantly older than anyone previously had believed. The realization that the distribution of fossils in different geological strata had a consistent pattern based on species began to raise a number of questions. Most geologists at the time believed in catastrophism, which, for them, meant that earth had been altered by a catastrophic flood. As scientists begin to find and catalog fossils, particularly at high elevations, some anti-Church types downplayed the discoveries fearing it would give credence to a universal flood perspective. A major change to geology came when Charles Lyell published his “Principles of Geology” in 1830, he made a case for an uniformitarian perspective versus a catastrophic perspective. This is the idea that the material world functions the same now as it did all through out the past.
Then, in 1851, Herbert Spencer wrote his “Social Statics” which argued that every biological form of life, including human systems, followed evolutionary rules. Spencer was more a social theorist than a scientist. Nevertheless, his writing both reflected and inculcated an evolutionary line of thinking.
Therefore, by 1851, science had moved away from the Genesis record as traditionally understood. The earth was believed to be millions of years old. Science had become focused on finding only natural causes for physical events. Fixity was being abandoned and the possibility of specie adaptation was being considered. A belief that there was some innate sense of progress “programmed” into life was taking root. Uniformitarian perspectives were winning the day. An evolutionary model was perceived by some to be at work in a myriad of ways even in human behavior.
All that remained was for someone to bring this all together.