Chaucer and Ibn al-Haytham (Alhacen): Perspectiva, Arabic Mathematics, and Acts of Looking

Abstract:The question of "how one sees" gives rise to a brief, learned interjection on optics and perspectiva in the Squire's unfinished, interlaced romance—an intervention that draws "Alocen," the Arabic mathematician Ibn al-Haytham (Latin: Alhacen or Alhazen) into discussion. Alhacen's De aspectibus, the Latin translation of his extraordinary treatise Kitāb al-Manāzir (Book of Optics) has long been acknowledged and utilized in Chaucer scholarship. However, little focused attention has been paid to tracing the intertextual routes that lead to Chaucer's "Alocen" from Jean de Meun's reference to "Alhacem" in the Roman de la Rose, through to entries on "Ibn al-Haytham" in Arabic bio-bibliographic dictionaries. In tracing the ways that European vernacular literature can be connected with Arabic textualtradi tions, this article also challenges the under-examined Eurocentric approaches to Chaucer and late medieval vernacular literature where Arabic figures such as "Alocen" have been collapsed into generic molds of medieval philosophers. It argues that repositioning Chaucer's "Alocen" as an Arabic mathematician and optical authority allows us to understand better not only his presence in The Squire's Tale, but the depiction of the physical act of looking and the cognitive and psychological consequences of key moments of sight beyond this romance. In order to demonstrate this, the exact question of "how one sees" as presented in the Kitāb al-Manāzir is explored with particular attention paid to the psychology of sight in examining the relationship between perception and judgment in three pivotal acts of looking in The Knight's Tale, The Physician's Tale, and Troilus and Criseyde.