Abstract

According to a rule of traditional logic concerning the relation between general (or universal) concepts, if a given concept is more general than a second one, then the opposition (or contradictory) of the first concept is more specific than the opposition (or contradictory) of the second one. Kātibī, one of the Muslim logicians in the 13th century, has raised a question against this rule and, by giving some counterexamples, claims that it results in contradiction. Some Muslim logicians have replied to Kātibī, and in this paper I have examined their replies. Also, by using rules of modern logic, we may easily show that either Kātibī's argumentation is fallacious or it does not result in contradiction; however, it seems that if modern logic rules had been represented to Muslim logicians, some of those rules would have been rejected by them.