This article uses Johan Joachim Spalding's Bestimmung des Menschen (1748) to explore the transformation of German Protestantism in the second half of the eighteenth century. The text was at once a philosophical and religious meditation about the senses, the spirit, the nature of creation, and the immortality of the soul. In unleashing a set of discussions about the purpose of "man" that went far beyond his apologetical and devotional intention, Spalding laid the groundwork for the culture of modern German Protestantism, and also introduced a rivalry between theology and philosophy that was one of its constitutive and abiding features.