Method of inference from conditional syllogism from the point of Kashshī, Abhari and Toosi

Document Type : Original Article





Muslim logicians have concluded in two different ways from the conditional syllogism, whose middle term is incomplete. In this paper, Kashshi's method is investigated.
By examining disagreements about types, conditions of validity, conclusive moods, and the reason for the validity of this syllogism, we find that the validity of this syllogism is based on a syllogism whose middle term is complete and the components of categorical syllogism in the deduction system of conditional syllogism have made it difficult to understand clearly the structure of conditional syllogisms.
In order to reveal the deduction system concealed in this method, two basic syllogisms have been identified first: the syllogism whose middle term is part of the consequent in both the premises and the syllogism whose middle term is part of the minor consequent and the major antecedent. And then we introduce the rules that are used to prove non-basic syllogisms.


ابن سینا، ح سین بن عبدال ، املخت رص االو سطفی املنطق، مقدمه و ت صح یح س ید محمود
یوسف ثانی، تهران، انتشارات مؤسسه پژوهشی حکمت و فلسفه ایران، 0811.
 ابن سینا، حسین بن عبدال، منطق الشفا، )جلد 1 )قم، انتشارات آیة الله مرعشی نجفی، 0115ق.
 ابن سینا، ح سین بن عبدال ، النجاة من الغرق ىف بحر ال ضالالت، مقدمه و ت صحیح از محمد
تقى دانش پژوه، تهران، انتشارات دانشگاه تهران، چاپ دوم، 0831.
 ابهری، اثیرالدین ، خالصةة االفکار فی ابانه االرسار: منطق )تحریرهای یکم و دوم( تحقیق
مهدی عظیمی و هاشم قربانی، تهران، انتشارات حکمت، 0811 .
 ابهری، اثیرالدین، ک شف احلقائق یف حتریر الدقائق، تحقیق: حسهین صهاری أوغلی، إ ستانبول ،