The logic of Avicenna between al-qiyas and man?iq al-mašriqiyyin

Abstract

Avicenna's logic is presented in many treatises, of which the most important is Al-Qiyās (Prior analytics), which is included in his encyclopaedic book Al-Šifā'. But the treatise entitled Maná1-iq al-mašriqiyyīn is said to express Avicenna's own logic by some commentators. One can thus ask: is this treatise in conflict with Al-Qiyās and the other logical writings? In this paper, we will answer this question by comparing Avicenna's analyses of the absolute - i. e. non modal - propositions. We will show that there is no radical difference between both treatises in this respect, since most conditions added to the absolute propositions in Al-Qiyās can be found in Maná1-iq al-mašriqiyyīn. These conditions are: (1) as long as S exists, (2) as long as it is S, (3) as long as it is P, (4) at some times, (5) at one determined time, (6) sometimes but not permanently. In Maná1-iq al-mašriqiyyīn, the áarūrīya contains (1), the lāzima contains (2), the muntašira contains (4), the mafrūáa contains (5), the wujūdiyya contains (6), but (3) is abandoned. The waqtiyya was evoked in Al-Qiyās, although not classified. So the temporal analysis initiated in Al-Qiyās is pursued and developed in Maná1-iq al-mašriqiyyīn, even if in the latter it is sometimes confused.