عنوان مقاله [English]
Expressing the contradictory of atomic modal and universal compound modal, Khunaji utilizes two different methods to infer the contradictory of modal particular compound proposition. In one method, he accounts contradictory of modal particular proposition a disjunctive- predicated universal proposition and in the other method he accounts contradictory of this proposition a disjunctive proposition which the subject of one of the two sides is bounded by common predicate of disjunction particles. In this paper after a brief review of quality contradiction atomic modals and universal compound propositions in viewpoint of Khunaji, we will consider the quality contradiction particular compound modals in the viewpoint of this logician and we demonstrate that Khunaji is the inventor of the first method to infer the contradictory from this proposition and is the first logician discovered the disjunctive predicated proposition. We will also show that Khunaji in the second method of inference was owed Kashshi and he was the second logician that utilizes this method.