Ibrahim ibn Sinan: Logique et geometrie au Xe siecle.

• Author: Morrison, Robert S.
• Position: Book Review

By ROSHDI RASHED and HELENE BELLOSTA. Islamic Philosophy, Theology and Science: Texts and Studies, vol. 42. Leiden: BRILL, 2000. Pp. ix + 809.

In this hefty tome, the authors have provided editions, translations, and technical commentaries on the works of Ibrahim ibn Sinan ibn Thabit ibn Qurra (d. 946 A.D.), along with indices and an Arabic-French glossary of technical terms. Many of the texts in the book under review first appeared in the 1948 Hyderabad, India (Osmania Oriental Publications Bureau) edition. Ahmad Saidan's The Works of Ibrahim Ibn Sinan (Kuwait, 1983) represented a vast improvement on the Hyderabad edition. Rashed and Bellosta's book Includes texts not found either in Ahmad Saidan's book or in the Hyderabad edition, and relies upon manuscripts other than MS Khuda Bakhsh 2468 (renumbered as MS Khuda Bakhsh 2519). This had been the sole MS for Saidan's book and for the Hyderabad edition.

In order to lend a historical framework to the individual texts, the authors begin by presenting Ibn Sinan's autobiography in which he provides an overview of his own career. The authors' edition relies upon MS Khuda Bakhsh 2519, and refers frequently to George Saliba's 1981 edition of the autobiography autobiography, which appeared in Waded al-Qadi (ed.), Studia Arabica & Islamica.

The bulk of the volume deals with Ibn Sinan's work on analysis and synthesis. Analysis is a method of geometrical demonstration in which one proceeds from the desired conclusion back towards a premise which one knows to be true. The ensuing synthesis moves from the known premise towards the conclusion. In Ibn Sinan's work, the authors identify three levels of analysis, each of which in turn motivates a certain type of synthesis. The first level, found in "Geometrical Analysis: The Anthology of Problems," is one in which the analysis shows that the object of the demonstration exists, generally without the addition of further conditions, or that the problem posed leads back to a problem whose solution exists. Too complex for pedagogical purposes, the "Anthology" belongs to a genre of text that first appeared in Islamic civilization in the tenth century. The problems of the "Anthology" indicate directions of research for Ibn Sinan and his contemporaries and fall into two categories. In the first category one determines the magnitude of certain parts of geometrical figures, assuming other parts are given. For example, if certain chords and arcs of a circle are given...