De Aspectibus Research Articles

ON THE LATIN SOURCE OF THE ITALIAN VERSION OF ALHACEN'S DE ASPECTIBUS (VAT. LAT. 4595)

AbstractA comparison of the manuscripts has shown that De li aspecti, the Italian version of Alhacen's De aspectibus, Vat. lat. 4595 (I), was copied from London, British Library, Royal 12.G.vii (L). The discovery of long omissions in L, not reproduced in I, disproves this conclusion. The error has two reasons: a sampling too small, the confusion between phenetic and cladistic approaches.

Ibn al-Haytham, the Arab who brought Greek optics into focus for Latin Europe

Ibn al-Haytham remains an unknown figure in the development of optics from the ancient Greeks to Latin Europe. He put to rest the idea of visual rays being emitted from the eye, demonstrating vision occurs by intromission of light rays to the eye. Through observational experimentation he characterized the behavior of light and described many visual phenomena that are now considered visual perception. Ibn al-Haytham’s most significant work, Kitab al-Manazir was written in the eleventh century and was translated to Latin, as De aspectibus during the middle of the thirteenth century. Its introduction to Latin Europe stimulated the study of optics within the nascent universities of Europe and provided a model to conduct experiments and influenced natural philosophers for centuries.

Arabic classical traditions in the history of the exact sciences: The case of Ibn al-Haytham⋆

This paper examines selected leitmotifs from the Arabic classical traditions in the history of the exact sciences while taking into account their adaptive assimilation and expansion of ancient Greek scientific knowledge within the pre-modern Islamicate intellectual milieu, and the subsequent transmission and reception of the Greco-Arabic sciences within the European mediaeval and Renaissance circles of scholarship. To give a more concrete focus to this thematic orientation I will address the legacy in the science of optics of the 11th century Arab polymath al-Hasan Ibn al-Haytham (known in Latin renditions of his name as Alhazen; died ca. 1041 CE), as encompassed primarily in his Kitāb al-manāzir (Book of Optics, De aspectibus or Perspectiva). This opus contained his explications of the nature and comportment of light and direct vision, including studies in catoptrics and dioptrics (respectively, the optical sciences that investigate the mathematical and physical principles of the reflection and refraction of light, along with their associated scientific instruments). This inquiry is situated within the wider epistemic setting of Ibn al-Haytham’s scientific experimental method of controlled testing that is underpinned by an isomorphic composition of geometric modelling with physics in studying natural phenomena.

Alhacen’s Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen’s De Aspectibus, the Medieval Latin Version of Ibn al-Haytham’s Kitab al-Manazir

Alhacen’s Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen’s De Aspectibus, the Medieval Latin Version of Ibn al-Haytham’s Kitab al-Manazir

ALHACEN’S APPROACH TO ‘‘ALHAZEN’S PROBLEM’’

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.

VISION, LIGHT AND COLOR IN AL-KINDĪ, PTOLEMY AND THE ANCIENT COMMENTATORS

Al-Kindī was influenced by two Greek traditions in his attempts to explain vision, light and color. Most obviously, his works on optics are indebted to Euclid and, perhaps indirectly, to Ptolemy. But he also knew some works from the Aristotelian tradition that touch on the nature of color and vision. Al-Kindī explicitly rejects the Aristotelian account of vision in his De Aspectibus, and adopts a theory according to which we see by means of a visual ray emitted from the eye. But in the same work, al-Kindī draws on Philoponus’ commentary on Aristotle's De Anima. His borrowing from this commentary, via an Arabic paraphrase of the De Anima, was crucial in the development of al-Kindī's new ‘ ‘ punctiform analysis of light.” Conversely, two broadly Aristotelian works by al-Kindī, which explain the reason things are colored, engage with problems about color dealt with in the Aristotelian tradition ( e.g. by Alexander of Aphrodisias ). But here the Aristotelian theory, and in particular the Aristotelian notion of the transparent, is abandoned in order to accommodate the visual ray theory expounded in De Aspectibus.

Alhacen on the Principles of Reflection: A Critical Edition, with English Translation and Commentary, of Books 4 and 5 of Alhacen's "De Aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitāb al-Manāẓir". Volume Two: English Translation

Alhacen on the Principles of Reflection: A Critical Edition, with English Translation and Commentary, of Books 4 and 5 of Alhacen's "De Aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitāb al-Manāẓir". Volume Two: English Translation

Alhacen on the Principles of Reflection: A Critical Edition, with English Translation and Commentary, of Books 4 and 5 of Alhacen's "De Aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitāb al-Manāẓir". Volume One: Introduction and Latin Text

Alhacen on the Principles of Reflection: A Critical Edition, with English Translation and Commentary, of Books 4 and 5 of Alhacen's "De Aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitāb al-Manāẓir". Volume One: Introduction and Latin Text

Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's "De aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitab al-Manazir": Volume Two

Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's "De aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitab al-Manazir": Volume Two

Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's "De aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitab al-Manazir": Volume One

Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's "De aspectibus", the Medieval Latin Version of Ibn al-Haytham's "Kitab al-Manazir": Volume One

Alhazen Vulgarisé: Le De li aspecti d'un manuscrit du Vatican (moitié du XIVe siècle) et le troisième Commentaire sur l'optique de Lorenzo Ghiberti

Dans sa description de l'œuvre en langue vulgaire de Lorenzo Ghiberti, Giorgio Vasari, quoiqu'il en dénigre certains aspects, saisit bien, nous semble-t-il, les traits marquants des Commentaires de Lorenzo, en particulier ceux du troisième livre concernant l'optique: Scrisse Lorenzo un'opera in volgare nella quale trattò di molte cose, ma sì fattamente che poco costrutto se ne cava… [que l'on en tire très peu de connaissances utiles…] Né tacerò che egli mostra il libro essere stato fatto da altri [Je ne tairai pas qu'il montre que le livre a été fait par d'autres personnes]

Witelo—Polish vision scientist of the middle ages: father of physiological optics

Unknown to the Western hemisphere, a Polish scientist, naturalist, anatomist, physiologist, philosopher and optician, Witelo, wrote an important ten volume manuscript, Peri-Optikes, usually cited in the literature as Perspectiva. This classic textbook was first published in 1535 in Nuremberg under the title: Vitellionis mathematici doctissimi … vulgo Perspectivam vocant libri X, which is translated to English as Perspectiva. It was a vital source of information for such scientists as Leonardo da Vinci, Keppler and others in the next few centuries. Although many of his ideas were similar to Alhazan's, who earlier had written a significant optical manuscript De aspectibus, Witelo developed his own interpretation of many optical issues. He was one of the first scientists to discover spherical aberration of concave lenses and concave mirrors. He was also first to point out “that deflection of the light ray increases with the angle in which they approach two different optical substances and each increase is smaller than the previous one.” Until recently, Witelo's achievements and contributions to the understanding of optical and anatomical aspects of the eye and visual function have remained unknown in western literature. Undoubtedly, Witelo should be recognized as the father of physiological optics.

An Optical Theme in The Merchant’s Tale

An Optical Theme in The Merchant’s Tale

A Note on John of Beaumont's Version of Euclid's De Visu

The reception of Euclid's Optica in the West has received scant attention, in contrast with the interest evoked by the Latin tradition of the Elements. A study of the extremely complex manuscript tradition of the Optica reveals that the translations of this work too were soon in the hands of many teachers, eager to learn what the great Geometer taught concerning vison and visual perspective. Three translations—two from the Arabic (Liber de radiis visualibus and Liber de aspectibus) and one from the Greek (Liber de visu)—were available to scholars before the close of the twelfth century. Furthermore, the Greco-Latin Liber de visu, by far the most widely known and carefully studied of the translations, appeared in at least three different versions before 1200. One of these versions is of particular interest as providing evidence of the diffusion of texts among the scholarly community in the latter part of the twelfth century. The version in question has survived in two manuscripts, Bodleian Library, Corpus Christi College 283, folios 163r–165v, and Seville, Bibl. Columbina 7.6.2, folios 43(44)v–54(55)r. Although the various translations and many other versions of Liber de visu are anonymous, the authors of this text are explicitly given in the colophon, which reads: Nota quod sexaginta et tria toreumata continentur in is to libra. Aimare, gralias age quia hoc opus sic glosulasti sub magistro Johanne de Beaumont. Explicit feliciter liber de visu. Whether Aimar was merely the scribe or perhaps the student of John of Beaumont, it is undoubtedly the latter that is to be primarily credited with the contents of the treatise. Unfortunately, neither The complete peerage nor the Dictionary of national biography list a John of Beaumont from the twelfth century, although the Beaumont family, with some reputation for learning, was prominent at that time in Normandy and England, particularly in the regions near Oxford. Whether John was a member of that illustrious line remains merely a matter for speculation. In any case, the treatise remains of interest to Euclidian scholars and historians of optics as a good witness to the twelfth century concern, not only with Euclid's visual theory, but particularly with his attempts to employ geometry in solving the problems of visual perspective.

Mediaeval empiricism: the case of Grosseteste's optics.

THE appearance of an experimental methodology of science in Robert Grosseteste's writings is often remarked upon by historians of science and forms a convenient focal point for demonstration of the creative interplay between science and philosophy in the Middle Ages.' Grosseteste's optics has been cited as a concrete and important example of this new, experimental method.2 Despite some apparent inconsistency in application3 Grosseteste's method in optical research should in general reflect his logic of science. However, the lack of close correlation between his theory and his practice necessitates reconsideration of Grosseteste's concept of experiment. Because his optical works have borne the burden of proof to a large degree in earlier discussion, a closer examination of the optics is in order as a basis for reassessment. Robert Grosseteste's approach to the study of optics was in the tradition established by Aristotle and given a clear metaphysico-mathematical statement by Alfarabi. In the Hellenistic world a geometrical approach to optics became standard. After Euclid's Optics the tradition was confirmed by such men as Heron, Ptolemy, Heliodoros, Damianos, and Theon. But the geometrical treatment of light could be more than just a method; its metaphysical significance stemmed from the place of mathematics itself in the Neoplatonic outlook.4 When one recalls the high place accorded to mathematics in Plato's ontology and epistemology, the metaphysical suggestiveness of applying geometry to any science is clear. Following the Pythagorean rather than the Archimedean view of mathematics, Neoplatonists tended to see an ultimate reality in everything falling under the heading of this discipline. So it was that many mediaeval adherents of the emission theory of vision found support for their view in the geometrical description of the field of vision. If one could treat sight geometrically as if rays were emitted from the eye, then some reality must pertain to this notion. Of course, emission theories predate Neoplatonism and geometrical optics; Aristotle discussed their origins in Presocratic thinkers like Pythagoras and Empedocles. But strength was given to the emission theory by the success of geometry as an analytical tool in optics and by Neoplatonic emphasis on the reality of geometricals. Alkindi's De aspectibus, 7 (9th century) gave reality to a power sent out from the