Intellectual Merits The critical edition of book 6 of Alhacen's De aspectibus proposed here constitutes the next stage of a long-term plan to critically edit all seven books of that treatise. Originally composed by Ibn al-Haytham in the early eleventh century and entitled Kitab al-Manazir ("Book of Optics") in Arabic, this work was translated into Latin around 1200 under the title De aspectibus and ascribed to "Alhacen." A soup-to-nuts treatment of optics, from physical light-theory and ray geometry to the physiology and psychology of visual perception, it represents a grand synthesis of Aristotelian physics and psychology, Euclidean-Ptolemaic mathematical optics, and Galenic anatomy and physiology. More than that, though, it represents a significant advance beyond its Hellenic and Hellenistic sources at the level of both content and methodology. As such, it provided the dominant paradigm for optical and visual analysis in the Latin West until the early seventeenth century, when its theoretical foundations were undermined by the likes of Kepler, Descartes, and Huygens. To this point, books 1-3, which deal with visual perception in general, have already been published, and books 4-5, on the basic principles of reflection, are soon to be published. The edition of book 6 should be in print by late 2007.
Broader Impacts Aside from its significance for the history of optics in particular and the history of science in general, the De aspectibus has long been recognized for its importance in fields outside the technical limits of those disciplines. Going back at least to Erwin Panofsky, art historians have been aware of the crucial role Alhacen's theory of visual perception played in the development of medieval and Renaissance artistic norms. Likewise, Alhacen's influence on philosophical and theological thought has come increasingly to attention, and recent literary studies have traced his influence in the development of various tropes within medieval and Renaissance poetry. Of increasing interest among psychologists, moreover, is Alhacen's emphasis on the psychological aspects of spatial perception, particularly in regard to size- and distance determination.
There is thus a fairly broad audience for this edition of the De aspectibus, the Latin text being of interest primarily to specialists, the English translation and commentary being of interest to both specialists and non-specialists. To ensure the widest dissemination possible, this edition, like its two forerunners, will be compiled in publish-ready format by the PI to cut down on the expense of the final printed version. In addition, the PI will explore the possibility of eventually producing the entire edition in digital format for greater accessibility and searchability.
In terms, finally, of its broadest impact, this sort of study reveals how deeply grounded the Western intellectual tradition is in medieval Arabic sources and the ideas and approaches they convey. These sources run the gamut from philosophical and theological to astronomical and mathematical, and the influence of some of them is already well documented. But, as lesser known or understood sources, such as this one, are brought to the light of publication, it becomes increasingly obvious that East-West political and cultural relations have yielded far richer fruit than the implacable hostility and rejection so commonly assumed. This study, in short, should help put the lie to that simplistic, wrongheaded, and ultimately corrosive assumption. It should also help put the lie to any lingering notion that Arabic culture is, and always has been, intrinsically backward.
