The principle that a necessarily false proposition implies any proposition, and that a necessarily true proposition is implied by any proposition, was apparently first propounded in twelfth century Latin logic, and came to be widely, though not universally, accepted in the fourteenth century. These principles seem never to have been accepted, or even seriously entertained, by Arabic logicians. In the present study, I explore some thirteenth century Arabic discussions of conditionals with impossible antecedents. The Persian-born scholar Afdal al-Dīn al-Kh najī (...) (d.1248) suggested the novel idea that two contradictory propositions may follow from the same impossible antecedent, and closely related to this point, he suggested that if an antecedent implies a consequent, then it will do so no matter how it is strengthened. These ideas led him, and those who followed him, to reject what has come to be known as 'Aristotle's thesis' that no proposition is implied by its own negation. Even these suggestions were widely resisted. Particularly influential were the counter-arguments of Na īr al-Dīn al-T ī (d.1274). (shrink)

Western contemporary logic has been used to advance the field of Islamic philosophical theology, which historically utilised Aristotelian-Avicennian logic, on grounds of there being an inherent normativity in logic. This is in spite of the surrounding controversy on the status of logic in the Islamic theological tradition. The normative authority of logic means that it influences the content of what we ought to believe and how we ought to revise those beliefs. This paper seeks to demonstrate that, notwithstanding the incompatible (...) differences between the two systems, the underlying feature of both Western contemporary logic and Aristotelian- Avicennian logic is logical normativity. It then argues that an inherent normativity of logic in the Islamic theological/philosophical tradition is unmotivated. Instead, it proposes to reinstate logic as anti-exceptional within the Islamic theological/philosophical tradition as a viable alternative. (shrink)

Avicenna (d. 1037) and Tūsī (d. 1274) have different doctrines on the contradiction and conversion of the absolute proposition. Following Avicenna's presentation of the doctrine in Pointers and reminders, and comparing it with what is given in Tūsī's commentary, allow us to pinpoint a major reason why Avicenna and Tūsī have different treatments of the modal syllogistic. Further comparison shows that the syllogistic system Rescher described in his research on Arabic logic more nearly fits Tūsī than Avicenna. This in turn (...) has consequences for analysing Avicenna's logic, and for writing the history of a fascinating period of change and diversity in the discipline in the medieval Islamic world. (shrink)

Speaking of relations between logic and religion in Islamic world may refer to logic in two respects: logic in religious texts, from doctrinal sacred texts such as Qur’ān and sayings of the Prophet to the Qur’ānic commentaries and the texts related to the principles and fundamentals of jurisprudence, all of which make use of some reasoning to persuade the audiences or to infer the rules and prescripts for religious behavior of the members of religious community; and logic as a discipline (...) that is studied and applied both independently and as a tool for reasoning in schools of Islamic theology, systems of Islamic philosophy, and other types of knowledge in medieval Islamic world, all being strongly influenced by religious doctrines of Islam. Accordingly, this paper speaks of the different manifestations of using logical reasoning, particularly analogy, in Qur’ānic arguments, e.g. for the existence of God and resurrection after death; some contradictions or paradoxes reported by different opponents in the verses of Qur’ān; the place of logic in the classification of disciplines and the courses taught at the schools and seminaries; the influence of the attitudes of different religious sects on logic; the instrumental role of logic for both religious and secular reasonings; the relation between reason and dogmatic religious doctrines, and, finally, the reflection of this relation on progress or recession of logic in medieval Islamic world. (shrink)

Zapadna suvremena logika korištena je za unapređenje islamske filozofske teologije, koja je povijesno koristila aristotelovsko-avicenovsku logiku, na temelju toga što se logika shvaćala kao inherentno normativna. To je usprkos kontroverzama o statusu logike u islamskoj teološkoj tradiciji. Normativni autoritet logike znači da ona utječe na sadržaj onoga u što bismo trebali vjerovati i na to kako bismo trebali revidirati ta uvjerenja. Ovaj rad nastoji pokazati da je, bez obzira na nekompatibilne razlike između dvaju sustava, temeljna značajka zapadne suvremene logike i (...) aristotelovsko-avicenovske logike njihova normativnost. Zatim se tvrdi da je inherentna normativnost logike u islamskoj teološkoj/filozofskoj tradiciji nemotivirana. Umjesto toga, kao održivu alternativu rad predlaže ponovno uspostavljanje logike kao anti-ekscepcionalističke unutar islamske teološke/filozofske tradicije. (shrink)

It is quite common among historians of Arabic logic to attribute MS Aḥmad iii, no. 3401, entitled Al-manṭiq al-kabīr, to Fakhr al-Dīn Rāzī. This view is expressed explicitly...