Conditional Logic and its Philosophical Bases

It is one of the basic questions of the Logic that why Aristotle has not dealt with conditional logic. How has the very originator of logic not paid any attention to such an important topic? Has this carelessness been some kind of ignorance or has it been deliberated and Aristotle has had good reasons for that? In this article, after having examined the conditional logic (conditional syllogism and proposition) from the stoics’ point of view and explaining its significance for modern logicians, theoretical andphilosophical bases of the two systems of predicative and conditional logic have been discussed. With studying Aristotle’s philosophy and having in mind his specific viewsregarding categories and the insertion of the things in The Ten Categories we can conclude that Aristotle has had an essence-based way of thinking and this is completely different from empirical thinking of the stoics, because stoics deal with external laws of the things in their philosophical thinking, rather than with essence and nature of the things. Therefore, the stoics have deviated from the predicative logic and have focused on conditional logic, because this kind of viewing the beings does not have thenecessities of an insertion and predicative system. In the same way that, we cannot speak conditionally and dubiously with a class-based look at the world's beings. In other words, regarding Aristotle's philosophical and ontological bases, we cannot accept conditional logic. For this reason, Aristotle has not entered discussing conditional syllogism and proposition in his works, whereas Megara school have dealt with these discussions before Aristotle, and after him this discussion has been seriously followed by thestoics, because it has been more compatible with their ontology.