Who is Ibn al-Haytham?June 25, 2021
Ibn al-Haytham (Arabic: ابن الهيثم, full name: ابو علی، حسن بن حسن بن هيثم Abū ‘Alī al-Hasan ibn al-Hasan ibn al-Haytham, Latin: Alhacen or Alhazen), Arab physicist, mathematician and is a philosopher. He was born in Basra in 965 and died in Cairo between 1038 and 1040.
He started his education in Basra. He also learned the high religion and sciences of his time here. After completing part of his education, he went to Baghdad especially; He learned positive sciences such as mathematics, physics, engineering, astronomy, metallurgy and became famous. He put a lot of effort into putting what he learned into practice. It achieved many important results and achievements.
When Ibn al-Haytham’s achievements were heard in other countries, El-Hakim, one of the rulers of the Shiite-Fatimi State who ruled in Egypt, invited him to Egypt. Before going to Egypt, Ibn al-Haytham had done an irrigation project and some technical studies on the Nile River and researched how to benefit from the Nile river. When he explained his project to the Fatimid sultan Al-Hakim, the sultan informed him that he would help him in every way possible for the realization of the project. Ibn al-Haytham made scientific and technical investigations along the Nile River. Seeing that the successful implementation of his projects was not possible under the conditions of that day, he begged forgiveness from the ruler. Ibn al-Haytham, fearing that al-Hakim’s opinions about him might change, decided to retreat to a secluded place and stay away from the ruler. Continuing his scientific studies secretly, he wrote many works. According to historians of science, this period of Ibn al-Haytham’s life was the most productive and successful. Ibn al-Haytham was contemporary with Biruni and Avicenna.
Ibn al-Haytham was the authority in all the sciences of his age. He had an exceptionally keen vision, understanding, judgment, and intelligence. He studied the works of Aristotle and Ptolemy, demonstrating his mistakes. He summarized them and translated them into Arabic. He also deepened in medical science. He applied geometry to logic. He developed the geometric and numerical methods of Euclid and Apollonius and pointed to their practical application. He contributed to the application of geometry and mathematics in the field of construction. By examining mathematics, geometry and astronomy inherited from ancient civilizations, he put forward his scientific criticisms and developed his own theories in these fields and presented them to the scientific world. E.g; He expressed his doubts and hesitations about the views of Aristotle and Ptolemy that the world is the center of the universe. He said that an Earth-centered universe system would not be certain, that other systems could be found in space, and that the solar system existed. As a matter of fact, hundreds of years after Ibn al-Haytham, before Ibn Shatir and Batruci, then Newton and Kepler, they accepted the theory of the solar system and said that the earth was in this system.
The Latin scholastics call Ibn al-Haytham, who has done research in the fields of physical optics, meteorological optics, catoptric, dioptric, burning mirrors, physiology of the eye and perceptual psychology, as “Alhazen”. He was also given the nickname “Ptolemaeus Secundus” (Ptolemy the Second; “Ptolemy-i Sani” in Arabic). Ibn al-Haytham’s book Kitab al-Menazir (Book of Optics / Book of Images / Optical Treasure), in which he demonstrates his mastery in medicine as well as in physics, begins with the anatomy and physiology of the eye. Here, the role of each of the conjunctive parts, such as the iris, cornea, and lens, in vision, from the optic nerve coming out of the brain to the eye itself, is masterfully illustrated. The relationship between the various parts of the eye and how the eye functions as a whole organ and dioptric system during the visual event is shown. Here, Ibn al-Haytham named the parts of the eye as follows: “Al-sebakiye” (retina), “al-kurniye” (cornea), “al-sa’il al-ma’i” (eye fluid), “al-sa’ il al-zucaci” (eng. “vitreous humor”; a jelly-like clear and colorless liquid that fills the retinal-enclosed cavity of the eye) etc.
Ibn al-Haytham’s famous work was translated into Latin under the title Opticae Thesaurus Alhazen (Ibn al-Haytham’s Optical Treasure) by Gerard (Gherardo) of Cremona (1114-1187) in the 12th century, and it occupied the Western world for 600 years. affected. The book deals with the structure of the eye, illusion, mirage, perspective, refraction of light and the camera’s ancestor, the “dark room” (literally Ar. “bayt al-muzlim”, Lat. “camera obscura”: “dark room”). ) and states that an inverted image will be obtained with such a punch-hole camera. Here, Ibn al-Haytham suggests using the “dark room” for observing solar eclipses. The Alexandrian astronomer, mathematician, and geographer Claudius Ptolemy (Ptolemy) (108-168) dealt with the theory of vision and reflection in his Almagest (Great Collection) (~150s) and Optics. Only the Latin translation of Ptolemy’s Optics by Emir Eugene of Sicily has survived. The theory of vision up to Ibn al-Haytham