The present study seeks to lay out the most basic elements of the ontology of classical Aš‘arite theology. In several cases this requires a careful examination of the traditional and the formal lexicography of certain key expressions. The topics primarily treated are: (1) how they understood “Being/ existence” and “being/existent” and essential natures; the systematic exploitation of the equivocities of certain expressions (e.g., ḫaqīqa, ḫadd, ma‘na) within a general context in which other than words there are no universals proves to be elegant as well as insightful; (2) the basic categories of primary entities: independant beings and nonindependant beings, (a) created and (b) uncreated, the equivocity of “being/existent” as predicated of contingent entities on the one hand and of God and His attributes on the other, and certain problems that arise because of the rigid application of the system's underlying analytic principles.

Among the extensive correspondence of Timothy I, Catholicos of the Church of the East, are two letters which refer to his collobaration in a translation of Aristotle's Topics into Syriac and Arabic, commissioned by the Caliph al-Mahdī. An annotated English translation of both letters is provided.

On some of the end-leaves of a Bible manuscript someone has copied out a passage from the Theology of Aristotle in Hebrew translation. The passage deals with the immunity of person of intellect from magical manipulation. No other copies of this passage in Hebrew are known to exist. The dependence of the translator upon the so-called “long version” of the Theology, specifically the copy in St Petersburg, is demonstrated, and it is suggested that the translator may be Shem Tov ibn Falaquera. The passage differs significantly from other versions of the Theology, and from Plotinus, in placing intellectual achievement ahead of ethical perfection in the scale of values.

Abū al-Wafā’ al-Būzjānī proposed, in a fragment established and translated herein, two methods to build a parabolic mirror. The lack of demonstration, particularly for the first method, raises a difficult question of interpretation. To understand this method, O. Neugebauer used, in an unpublished article translated herein, concepts of descriptive geometry. He then eliminated the space construction used, to keep only simple geometrical considerations known by the Greeks. The second interpretation, given by R. Rashed, is based on the geometrical practices of al-Būzjānī's contemporaries, like al-Qūhī and Ibn Sahl, i.e. on the methods of conical projections. The second method borrowed by al-Būzjānī from Ibn Sinān seems to support this last interpretation.