Scholars have long debated the possibility of a mystical or illuminationist strain of thought in Ibn Sīnā's body of writing. This debate has often focused on the meaning and contents of his partly lost work al-Mashriqiyyūn (The Easterners), also known as al-Ḥikma al-Mashriqiyya (Eastern Wisdom), mentioned by Ibn Sīnā himself as well as by numerous Western writers including Ibn Rushd and Ibn Ṭufayl. A handful of references to what is called Ibn Sīnā's “Oriental Philosophy” are also found in the Castilian and Hebrew works of the Castilian Jew Abner of Burgos (ca. 1270-ca. 1347), known after his conversion to Christianity as Alfonso of Valladolid. Although the content of these citations has not been identified, it has been proposed that they may preserve otherwise unknown passages from Ibn Sīnā's lost work. This study considers the references to Ibn Sīnā's so-called “Oriental Philosophy” within Abner's writings and concludes that rather than preserving lost passages from Ibn Sīnā's writing, Abner's references were drawn primarily from Ibn Ṭufayl and offer no support for the argument of a possible mystical or illuminationist strain in Ibn Sīnā's thinking.

In his encyclopedic book (al-Istikmāl), the mathematician of Saragossa, Ibn Hūd (d. 1085/478 H.), established by an intrinsic demonstration of spherical geometry, a remarkable theorem which generalizes the proposition III.11 from Theodosius’s Spherics and integrates the propositions III.23-25 from Menelaus’s Spherics. In this paper, we study this theorem and the demonstration of Ibn Hūd. The reader will find also some established and translated texts (Ibn Hūd, Ibn ʿIrāq, al-Ṭūsī) addressing the same theme.

We here present the Arabic text, with an English translation, of certain pages dedicated by al-Khayyām to the mathematical theory of music. Our edition is based on a manuscript extant in a library in Manisa (Turkey), and corrects the mistakes found in another transcription. Lastly, we compare the theory of al-Khayyām with other Arabic theories of Music, and with those coming from other traditions.

The medieval Islamic philosophers held a certain conception of the divine unity that assumes the necessary existent to be both one and simple. The oneness of the necessary existent meant that it is the only necessary existent and its simplicity meant that it admits no composition whatsoever – it is pure essence and its essence is necessary existence. In The Incoherence of the Philosophers al-Ġazālī presents, with elaboration, an exposition of the philosophers' conception of the divine unity, several arguments for its two components (i.e., oneness and simplicity), and his critique of these arguments. In this paper I focus on six of the arguments attributed to the philosophers. Following the textual evidence, I reconstruct these arguments and offer two possible interpretations of them. The first interpretation, which I call the many-argument interpretation, sees one of the arguments as employing the simplicity of the necessary existent to establish its oneness and the other five arguments as invoking oneness to establish simplicity. The second interpretation, which I call the one-argument interpretation, doesn't offer a new reading for the first argument but sees the other five arguments as defending the simplicity of the necessary existent based on its basic concept. I argue for the superiority of the one-argument interpretation.