Revealing Manuscripts and Embedded Texts: The Case of Arabic Optics

Dr. Elaheh Kheirandish
This paper presents the result of a recent study on two Arabic optical compositions, with a focus on their manuscript copies and “embedded” texts: The first text is “The Book of Optics and Burning Mirrors, composed by Ahmad ibn ‘Isa” (3rd/9th c.?); the second is titled, “The Rectification of Errors and Problems of Euclid’s Book Called Optics” by Ya‘qub al-Kindi (d. ca. 257/870). The former, whose author’s identity and dates remain little known, is available in two Arabic manuscript copies and a Hebrew transcription; the latter, apparently composed later than al-Kindi’s De aspectibus, surviving only in Latin, is known through a single manuscript.
The manuscripts of Ibn ‘Isa and al-Kindi’s compositions contain the following revealing features: Ibn ‘Isa’s Optics, exposes through one of its two Arabic manuscripts, a “note” on refraction dictated by Ibn al-Haytham; al-Kindi’s Rectification reveals, besides a much better known author and date, a text long considered a “Correction” following many manuscript copies of the Recension of Euclid’s Optics by Nasir al-Din al-Tusi (d. 672/1274); the manuscripts of both optical compositions also capture, as part of their alternative formulation of the Euclidean visual-ray hypothesis, a striking passage corresponding to the unique copy of the [pseudo-]Euclidean De speculis, a text whose comparative context will be discussed as part of an ongiong project.
The paper concludes that: (1) The Ibn ‘Isa manuscript preserving Ibn al-Haytham’s dictation is not “incomplete” as catalogued, but rather, imbedding the “note” onto a few folios just before the text’s ending; (2) The al-Kindi manuscript raises transmission questions beyond correspondence to the so-called “Correction”, and (3) The close wording of De speculis and the two compositions may be related to the defective nature of the manuscript tradition in both the Greek and Arabic Euclidean texts.