The Logic of Khārijī Propositions

There are two general methods for interpreting and analyzing khārijī and ḥaqīqī propositions: first, by analyzing them within a unified logic; second, by assigning separate logics to khārijī and ḥaqīqī propositions. So far, most interpretations and analyses of khārijī and ḥaqīqī propositions have been carried out using the first method within either traditional logic or a branch of modern logic, while the second method has rarely been used for this purpose. In this article, we aim to use the second method and demonstrate that the appropriate logic for ḥaqīqī propositions is classical predicate logic, while for khārijī propositions, it is predicate-free logic. We show that non-classical predicate-free logic restricts the rules of introduction and elimination of the quantifiers on the existence of khārijī objects, making it the most suitable logic for khārijī propositions. In contrast, classical predicate logic, which does not restrict the quantifiers on the external existence of objects, is more suitable for ḥaqīqī propositions. Additionally, we illustrate that by incorporating modal logic and temporal logic into classical and free predicate logics, the principles and rules of ḥaqīqī and khārijī propositions become more distinguishable, resulting in more distinct logics. In particular, we demonstrate that the Barcan Formula, the Buridan Formula, and the converse Barcan Formula hold true for ḥaqīqī propositions and are proven in classical modal and temporal logics, while they are false for khārijī propositions and remain unprovable in free modal and temporal logic.