Fakhr Razi’s Logical Innovations and His Challenges to Avicenna School of Logic

Understanding Fakhr al-Razi’s logical thoughts is very important in understanding the views of seventh and eighth-century logicians. His role in the development of Avicennan logic and his new challenges to this logic are undeniable. Composite of judgment, believe in all concepts are self-evident, expansion and development of a variety of definitions and specific approach to the nominal definition, the mutual implication of concordance and obligation signification, six kinds of universal and to be clear than the particular, unpredicatablity of the partial concept, minimalistic view in the conditions of contradiction between the theorems, differentiation between categorical propositions and real propositions, modality of conditionals, extraction result of the forth syllogism and determining valid mood and valid conditions in fourth figure of Syllogism are Fakhr al-Razi’s logical innovations. This paper is an attempt to explain such innovations.