Depuis son édition par Heiberg au XIXe s., on savait que le texte grec de La mesure du cercle d'Archimède qui nous est parvenu est fautif, altéré par l'intervention d'un compilateur. Pour certaines de ses parties au moins, il est donc d'une authenticité douteuse. Plus récemment, l'examen de la traduction latine (au IXe siècle) de la traduction arabe de ce texte a permis de conclure que le manuscrit grec traduit appartient à une tradition textuelle meilleure et plus ancienne que le texte édité par Heiberg. Dans cette étude, on trouve l'editio princeps de la traduction arabe de La mesure du cercle, sa première traduction et une analyse historique et mathématique. Les nombreuses lectures de cette traduction faites au cours des siècles ont inspiré plusieurs « rédactions ». Trois d'entre elles seront éditées, traduites et examinées dans une prochaine étude.

This article brings to light a previously unedited short treatise, the Masʾalatān (Two Questions), attributed to Avicenna (d. 1037). While the earliest witness to the text is the Ayasofya 4853 manuscript, containing a substantial portion of Avicenna's Nachlass, some of which is integrated into the Mubāḥaṯāt and Taʿlīqāt, the Masʾalatān has remained a standalone work with limited circulation. Consequently, the primary concern revolves around the verification of its authenticity and its feasibility given the available data. This article presents a critical edition of the text alongside a parallel translation but it also serves as a case study on the possibilities of authorship verification. It also compiles information from codicology, nevertheless, it primarily focuses on the commentary that analyses and compares the arguments to Avicenna's unquestionably authentic solutions. The first question addresses whether every existent is spatially located, while the second explores the impossibility of an actual infinite body. The commentary endeavors to interpret the text against the cultural and theological background that may have inspired such inquiries, meanwhile also seeks to address its later influence. In addition to unveiling a hitherto unseen text to the scholarly community for further research, it also offers an insight into the limitations of authorship attribution.

Ibn Sīnā famously opens The Metaphysics (Al-ilāhiyyāt) of The Healing (Al-šifāʾ) with a discussion of what constitutes the subject matter of that science. Several candidates are introduced and subsequently dismissed, before “the existent qua existent” is identified as its subject matter. Among the candidates dismissed, he mentions “the ultimate causes for all existents, the four of them” (which are, however, things investigated [maṭālib] in this science). Here, Ibn Sīnā comes to problematise the notion of causality itself. He is adamant that “the existence of causes for things which are effects” is not self-evident, but needs to be proven by the metaphysician by means of a “demonstrative clarification” (bayān burhānī). He explains why sensation (ḥiss) and experience (taǧriba) cannot prove causality, before turning to its metaphysical proof. In this article, I investigate what Ibn Sīnā thought this “demonstrative clarification” of causality is. I present an analysis of his train of thought and a commentary on the various points he makes, leading up to his proof of causality. These points touch on problems of psychology, scientific method, and scientific proof, and can be unpacked by taking into account explanations he offers elsewhere.

This paper aims to introduce and discuss al-Fārābī's (d. 950–1 CE) fallacy from transfer and substitution in his little-studied “On Deceptive Topoi” (Kitāb al-amkina al-muġalliṭa) and the criticism leveled at him by Averroes (d. 1198 CE) for violating Aristotle's claim of the exhaustiveness of his list of fallacies. The first and larger half of this paper introduces al-Fārābī's treatise and its innovations upon Aristotle's Sophistici elenchi. The second half focuses on Averroes’ criticism in his so-called middle commentary (talḫīṣ) on Aristotle's SE and discusses the validity of his arguments against al-Fārābī. As the final analysis will show, Averroes’ criticism does not sufficiently take into account the independence of al-Fārābī's treatise from Aristotle's SE, its disregard for the study of dialectical deception and counter-deception, and its particular focus on the demonstrative sciences. In light of al-Fārābī's innovation his “On Deceptive Topoi” turns out to be a work of great originality drawing on a broad range of source texts.