Abstract

It was Ibn-Sina who, for the first time in the history of logic, discussed the quantity and quality of conditional propositions in detail and explained the authenticity of their generality and particularity in simple terms. He also determined the place of affirmation and negation in conditional propositions, and discovered a number of different points through his analyses of the issue. However, he mixed the ordinary logic of conditionals with their modal logic so that, due to some contradictions, no specific formal system about conditionals could be derived from the resulting logic.He was also the first person who started the discussion of conditional conjunctive syllogism, and it seems that he intended to base conditional logic on categorical logic through comparing conditional and predicative propositions with each other and pinpointing their similarities.