The science of the “rules of inquiry” (ādāb al-baḥth) has received little modern scholarly attention. Though influenced by Aristotelian topics and early Islamic juridical-theological eristic (jadal), it only emerges as a full-fledged science in the course of the 13th century. My paper will argue that (1) there was a dramatic increase in interest in this science in the 17th and 18th centuries in the Ottoman Empire, (2) the discipline itself was developed in noticeable ways by Ottoman scholars in this period, and (3) that the discipline was widely seen as central to the widely held ideal of “verification” (taḥqīq), i.e. the critical evaluation of received scholarly opinions in the rational sciences.