This book examines the intellectual importance of religion for the origins of the German Enlightenment around 1700. In particular, I shall focus on a central figure of early eighteenth-century intellectual history: the jurist and philosopher Christian Thomasius (1655–1728). Now known mainly for his criticism of witchcraft trials and judicial torture, Thomasius's reputation in German intellectual history is comparable to that of John Locke in England. He is considered to be one of the first and most influential representatives of the early Enlightenment in the German territories. His status as such was well established by the late eighteenth century. In the course of the famous debate on the nature of “Enlightenment,” to which Immanuel Kant contributed his well-known essay, the writer Friedrich Gedike described Thomasius as the founder of the Enlightenment in Germany, the philosopher to whom “we owe a large part of our intellectual and material happiness.” A few years later, Friedrich Schiller praised him for his fearless opposition to scholastic “pedantry.” In recent scholarship, Thomasius continues to be credited with weakening the authority of obsolete, “scholastic” learning and with contributing to the intellectual revival of German universities after a period of decline in the second half of the seventeenth century, following the destruction caused by the Thirty Years’ War.

As a religious thinker, he is usually presented as a classical theorist of the Enlightenment, who separated the question of religious truth from the pursuit of secular philosophy. He is not considered an atheist, but it is widely claimed that Thomasius's secular philosophical positions were in some sense “independent” from his religious beliefs. Werner Schneiders, for example, wrote that although Thomasius's philosophy was for a short time in the 1690s strongly influenced by religious mysticism, this was no more than a passing phase. It reflected a religious and psychological crisis, from which Thomasius recovered around 1700, making it possible for him to return to a rationalist and secular philosophy.