Islamic Medicine History and Current Practice - International Society ...

Al-Haytham the Man of Experience.First Steps in the Science of VisionRosanna GORINI** Institute of Neurosciences-Laboratory of Psychobiology and Psychopharmacology, Rome, Italy.e-mail: R.Gorini@ipsifar.rm.cnr.itAbu ‘Ali al-Hasan ibn al-Hasan ibn al-Haytham (965-1039 A.D) was one of the most significant figures in the history of opticsbetween antiquity and the 17th century. His explanation of the vision has been revolutionary in the history of medicine and vision.In his Kitab al-Manazir he studied optical illusions, the structure of the eye, perspective, atmospheric refractions etc. In particular histheory in which the principles of light and perspective are explained for the first time in the Middle Ages, had a great impact uponEuropean culture of the medieval and modern eras.Key Words; Al-Haytham, Kitab al-Manazir, Optics, Vision.SummaryAbu ‘Ali al-Hasan ibn al-Hasan ibn al-Haytham(965-1039 A.D), sometimes called al-Basri (from thecity of Basra, his birthplace) or al-Misri (since hecame from Egypt) is more often known in Europe asAlhazen or Alhacen (the latinization of al-Hasan) andAvenatan or Avennathan. He was identified towardsthe end of the 19 th century with the Alhazen,Avennathan and Avenetan of medieval Latin texts(1). Little is known about al-Haytham’s life. Mostprobably he was born in Basrah in Iraq, and was educatedin Basrah and Baghdad. His father was a civilservant, so al-Haytham was sufficiently well educated.We know that he travelled a lot, especially inSpain, and that he spent a long period of his life inCairo during the rule of the Fatimid caliph al-Hakimbi-Amr Allah (985-1021 A.D.). The munificence ofal-Hakim to scholars and scientists, according toSami Hamarneh had attracted al-Haytham into goingto Fatimid Egypt (2).According to Haidar Bammate, al-Haytham wasthe first to support the building of a dam near Aswanto raise the water level of the Nile (3). He submittedto al-Hakim a hydraulic plan for regulating the inundationsof the Nile. We do not know if that projectwas refused by the caliph or if al-Hayhtam was notable to carry on it, perhaps for its expensiveness. In a13 th century report it is said that al-Haytham, afterrealizing that it was not possible to make his projectJISHIM 2003, 2concrete, pretended to be mad to avoid al-Hakim’sanger and punishment. As a consequence he was confinedin a house where he lived for many years, untilthe death of the caliph, twelve years later. After theseevents al-Haytham continued to live in Cairo near theal-Azhar University, until his death.He was a very erudite man, like many medievalmen. He expounded, among the others, the theoriesof Aristotle, Galen and Ptolemy and was devoted onphilosophy, physics, medicine, optics, astronomy andmathematics. He wrote about one hundred books onthese and other subjects. However his most importantstudies were related to the optic matter and his influenceon the western thoughts is mainly due to hisworks in the field of optics, in which the basis lays ofthe otpical knowledge in later Christian and IslamicMiddle Age. Hence, Al-Haytham is considered one ofthe most significant figures in the history of opticsbetween antiquity and the 17 th century. His explanationof the vision has been revolutionary in the historyboth of medicine and optics and has modified theidea that ancients had about light and their theorieson the anatomy and the physiology of the eye (4).The light has been the subject of various studiessince antiquity and the nature of the physical relationbetween eyes and objects has been a considerableproblem to the early 17 th century. The Greek philoso-53