The thesis looks at 6 court cases in 17th and 18th centuries' Basel to excavate popular forms of science and knowledge in a period known for allegedly discovering 'science' and 'reason'. It finds that while in each trial an individual was prosecuted for witchcraft, popular interpretations of the events were always embedded in science. This outlook was shared by the accused, the witnesses, and also, surprisingly, the plaintiffs. Witchcraft trials provide a unique window into the kinds of popular scientific practices and knowledge claims that were both common yet subject to prosecution. Revealed are curious interactions, frictions, and negotiations between popular and "official court" ontologies, epistemologies, and conceptions of nature. Using Foucault, but more particularly Deleuze and Guattari's idea of the rhizomatic representation of knowledge, the thesis tells a story "from below" in an attempt to understand popular epistemologies as unruly configurations with porous boundaries and deeply anti-genealogical makeups. Maintaining no strict distinction between science, myth, folklore, medicine, and religion, rhizomatic knowledge was mobile and nomadic. Almost always, much of the epistemic conflict that took place on the court stage centred around opposing views of nature. In a second step, the thesis traces court officials' efforts to occlude and delegitimise popular epistemic articulations. Discursively and legally, the term 'witchcraft' acted as a language of exclusion and subalternisation. What occurred in the courtroom can therefore be summarised as a politically driven project to discipline a highly mobile, scrambled field of knowledge, bringing order to "chaosmos."