Abstract

According to the principle of presupposition, in affirmative propositions, whose subject is the impossible being by essence, it is necessary for the subject to be realized, which is impossible. It seems that a good solution to this problem is considering uncertain categorical propositions as conditional ones. However, Muslim philosophers, particularly Mulla Sadra, believe that although uncertain propositions are coextensive with conditional ones, their logical structure is a categorial one.It seems that their most important reason for opposing equating conditional and uncertain propositions with each other is their believing in mental existence, and that one of the most important proofs for demonstrating this existence is based on the idea that subjectless propositions are categorial.