This paper undertakes an in-depth examination of the intriguing argument for the existential import of negative propositions by the fifteenth-century Ottoman scholar Hatibzâde Mehmed (d. 1496) and the counterarguments by his disciple, Taşköprizâde Kâsım (d. 1513). It argues that this discussion is a significant example of Ottoman scholars engaging in long-standing disputes concerning the nature and ontological ground of negative propositions, which date back to Plato and Aristotle. It is also intended to underline the need for considering not only logic (...) texts but also works primarily associated with other disciplines in order to attain a comprehensive picture of logical discussions in the post-classical period of Islamic thought. (shrink)