Striking similarities, often literal, between Ibn Riḍwan's Book on the Application of Logic in the Sciences and Arts and the Didascalia in Rhetoricam Aristotelis ex glosa Alpharabii lead to suppose that the first of these treatises has preserved something of the Arabic source of the second one, the Great Commentary on the Rhetoric by al-Fārābī, and to question on the originality of Ibn Riḍwan's rhetorical doctrine. In this paper, the texts on rhetoric of Ibn Riḍwan's treatise are edited, translated and placed in front of their correspondents of the Didascalia. They are then analysed and classified depending on their proximity and distance to the Didascalia. It appears that Ibn Riḍwān has, as the Didascalia, a system of the means of the persuasion which puts on the same level eight non pathetical means external to the speech, the enthymeme and the example. Nervertheless, one has also to note that Ibn Riḍwan's theory of rhetoric is radically different from Didascalia's: on the one side, a general rhetoric – non limited to specific activity, means, listeners and objects; on the other side, a special rhetoric, with such limitations. On the basis of these similarities and differences, I shall treat, in the next issue of A.S.P., the degree of dependence of Ibn Riḍwān's rhetorical doctrine towards the Didascalia, and the project underlying his work.

We have attempted in this article to describe the content of al-Khayyām's 11th century Arabic commentary on Book V of Euclid's Elements, and have translated into English what we thought were its most important passages. We have also tried to explain why some Arab mathematicians were opposed to the famous definition of proportional magnitudes found at the beginning of Book V of the Elements.

The focus of this study is the definitions of substance and accident as expressed and outlined in Ibn Daud's book The Exalted Faith. The original Arabic text of Ibn Daud's book, completed in 1160, is lost. However the work survives through two Hebrew translations (both date from the late 14th century). In this study I suggest a hypothetical reconstruction of the Arabic text based on a wide comparison with Ibn Daud's Muslim predecessors, such as Alfarabi, Avicenna and Alghazali, on the one hand, and the Hebrew translations on the other. By returning to Ibn Daud's direct sources, I hope to shed more light on two subjects: (1) Ibn Daud's dependance on non-Jewish sources in his attempt to establish a philosophical synthesis between Aristotelism and traditional faith; and (2) to clarify the true philosophical meaning embodied in professional terminology, such as the definitions of substance and accident.