An Inquiry into Athir al-Din Abhari's Rational Thoughts

Athir al-Din Abhari, an eminent philosopher and logician of the 7th century AH, has played a pivotal role in the advancement of Avicennian logic. Understanding his views about logic is necessary for realizing the views and methods of logicians who came after him. Extending some of Ibn Sina`s innovations and reshaping some of Fakhr Razi`s views, he has own views. Using an analytical-descriptive method, this paper seeks to present some of his views, including; following Ibn Sina`s two-Tierd logic, discovering the physical proposition and its independent convention it as a special proposition, discovering the conversion of the particular negative in the two special properties, adding three moods to the concluding moods of the fourth figure in complex modal propositions, evidence of asserting the self, the composite quiddity of judgment negating the assumption that all aspects are self-evident, negating the interrelation between the significance of commensuration and consecutive significance, adding the mental proposition to the classification of categorical determinate proposition into a true proposition and external proposition.