While acknowledging the disproportionate role of Islamic jurisprudence in studies of Islam generally, as a body of texts it provides a valuable site to trace the ways in which the natural sciences were on the one hand instrumentalized and appropriated by jurists to address ritual and social issues, and on the other demonstrates how these sciences provided the basis for legal thinking. The case of the Great Smoking Debate of the seventeenth–eighteenth centuries is discussed at length to show in detail how medicine shaped legal categories.