Historians have often described the rise of a "positivist natural science" as a defining feature of mid-nineteenth century German culture. This chapter argues, however, that "positivist" was not in fact a label that mid-nineteenth-century German scientists claimed for themselves. Indeed, the word was initially far more likely to be assigned to the natural sciences as an insult rather than as praise. In the German intellectual tradition, "positive knowledge" was a concept originally used in law and theology, not in natural science. The concept came to be associated with the natural sciences during a set of contentious debates over educational reform in the 1820s, 1830s, and 1840s; in these debates, "positive" knowledge was devalued and seen as potentially dangerous to the education of elite young men.