CORRECTING PTOLEMY AND ARISTOTLE: IBN AL-ṢALĀḤ ON MISTAKES IN THE ALMAGEST, ON THE HEAVENS, AND POSTERIOR ANALYTICS

Abstract The polymath Ibn al-Ṣalāḥ (d. 1154 CE) is known for a number of comparatively small treatises on specific aspects of ancient Greek mathematical and philosophical works. He devotes many of his works to greater or smaller errors that he found in the works by Euclid, Ptolemy, and Aristotle. The aim of the present paper, which focuses on three treatises on Ptolemy and Aristotle, is to describe Ibn al-Ṣalāḥ’s method and aim in these works. I argue that his treatises on the Almagest, On the Heavens, and Posterior Analytics follow a similar structure and that there is much value for modern research resulting from the bibliographical details provided by Ibn al-Ṣalāḥ. To give but just one example, Ibn al-Ṣalāḥ attests to the existence of a so far unknown Arabic translation of Aristotle's Posterior Analytics. In this way, this paper is the first to establish Ibn al-Ṣalāḥ’s research profile: his works tell us which sources were available to scholars active in Baghdad and Damascus in the 12th century CE and how he tried to resolve contradictions from the different versions of authoritative texts. Thus, this paper enhances our knowledge of the Graeco-Arabic transmission of scientific and philosophical texts.