The history of Western civilization cannot be neatly divided into precise linear sections. Instead, it must be viewed as a series of developing threads that combine, interact, and, at various intervals, take pervasive shifts. The Enlightenment of the eighteenth century was one of these paradigm historical shifts, challenging the traditional notions of authority by investing reason with the power to change the human condition for the better. This ecumenical emphasis on reason and independent thought led to an explosion of change and development across science, philosophy, religion, and politics. Later ideologies that would shape the socioeconomic landscape of the next two centuries were themselves shaped by the threads of Enlightenment thought. These threads did not abruptly end, as some would suppose, with the French Revolution, but can still be seen in various modes of thought today.
The importance that the Enlightenment placed upon reason was most obvious in the spheres of science and philosophy. Although this time period saw a rapid increase in scientific knowledge, the overarching idea behind the discoveries was that man could realize his full potential and progress towards perfection through the application of reason. Descartes’ epistemological foundationalism encouraged skeptical analysis in order to arrive at indubitable truth, and set the tone for the new metaphysics that emerged along with a vigorous interest in “natural philosophy” and the inductive study of the physical realm. At the same, however, there was intense philosophical discussion about the nature of the material world that was being studied. Some, like David Hume, believed that we had no way of knowing if our perceptions and the external world actually correlated, while others, mainly Immanuel Kant, believed that nature was made to conform to the active categorical interpretation of the human mind. Anthropological optimism pervaded the philosophical debates, however, standing in stark contrast to the pious hierarchical philosophies of the Middle Ages.
As the Enlightenment ideals of reason and unfettered thinking were applied to the religious realm, they produced diverse effects. It does not suffice merely to say that the time period was characterized by a universal decline in religion, for in addition to the anti-religious diatribes of those such as Voltaire, there was a rise in several diverse religious schools of thought. Deism, which arose in the late seventeenth century in England, was a popular product of the search for a rational and natural religion because of its denial of God’s active involvement with the world after creation. Although many started to call special revelation and the validity of scriptural claims into question, the rise of devotional movements such as Pietism and Methodism exemplified the range of religious thought and practice during the Enlightenment. Religion was going through metamorphosis, not annihilation.