In the fifth book of his De aspectibus, the medieval Latin version of Ibn al-Haytham’s Kitāb al-Manāẓir, Alhacen undertakes to determine precisely where a given ray of light will reflect to a given center of sight from a variety of convex and concave mirrors based on circular sections. As applied specifically to convex and concave spherical mirrors, this problem exercised several seventeenth-century thinkers, Christiaan Huygens foremost among them, and in that context it soon became known as ‘‘Alhazen’s Problem.’’ By current standards, Alhacen’s solution (or solutions) of this problem is deficient in comparison to that of Huygens and later mathematicians. It is my purpose in this paper to show by reconstruction that in fact, far from deficient in any absolute sense, Alhacen’s approach to this problem was remarkably ingenious and elegant in its conceptual simplicity.

Na‘īm ibn Mūsā’s lived in Baghdad in the second half of the 9th century. He was probably not a major mathematician. Still his Collection of geometrical propositions – recently edited and translated in French by Roshdi Rashed and Christian Houzel – reflects quite well the mathematical practice that was common in Thābit ibn Qurra’s school. A relevant characteristic of Na‘īm’s treatise is its large use of a form of inferences that can be said ‘algebraic’ in a sense that will be explained. They occur both in proofs of theorems and in solutions of problems. In the latter case, they enter different sorts of problematic analyses that are mainly used to reduce the geometrical problems they are concerned with to al-Khwārizmī’s equations.

In his Short Treatise and his Commentary on the Peri hermeneias, al-Fārābī offers two different but related accounts of indefinite terms and the propositions that contain them. In both works he presents a series of different senses that an indefinite term may have, commencing with a sense in which such a term would be equivalent to a privative term, and concluding with a sense in which it would determine the logical complement of the corresponding definite term. I offer an interpretation of this series according to which they reveal the workings of a fine analytical mind and a subtle teacher.

Al-Fārābī’s title of ‘‘Second Teacher’’ after Aristotle is well-warranted. Al-Fārābī’s work serves to illuminate the writings of the ‘‘First Teacher’’ in interesting and overlooked ways that go beyond the parameters of Aristotelian logic. Credence is lent to this assessment through the analysis of a specific topic, namely, authentic prophetic vision. At first glance, this seems like a strange assertion to make given Aristotle’s apparent skepticism and indifference regarding the topic of prophecy. However, as this paper will show, there is a latent theory of prophetic vision in the extant texts of Aristotle that al-Fārābī recognizes and completes in a way that is, in large part, faithful to and consistent with the corpus of Aristotle as we read it today. In the end, al-Fārābī provides insight into how a properly Aristotelian theory of authentic prophetic vision could be realized.

Galen’s Commentaries on the Hippocratic Epidemics constitute one of the most detailed studies of Hippocratic medicine from Antiquity. The Arabic translation of the Commentaries by Ḥunayn ibn Isḥāq (d. c. 873) is of crucial importance because it preserves large sections now lost in Greek, and because it helped to establish an Arabic clinical literature. The present contribution investigate the translation of this seminal work into Syriac and Arabic. It provides a first survey of the manuscript tradition, and explores how physicians in the medieval Muslim world drew on it both to teach medicine to students, and to develop a framework for their own clinical research.