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Alhazen
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Name: Abū ‘Alī al-Ḥasan ibn al-Ḥasan ibn al-Haytham
Title: Ibn al-Haytham and Alhacen
Birth: 965[1]
Death: c. 1040[1]
Ethnicity: Arab and/or Persian
Region: Iraq (Mesopotamia) and Egypt
Main interests: Anatomy, Astronomy, Engineering, Mathematics, Mechanics, Medicine, Optics, Ophthalmology, Philosophy, Physics, Psychology, Science
Notable ideas: Pioneer in optics, scientific method, experimental science, experimental physics, experimental psychology, visual perception, phenomenology, analytic geometry, non-Ptolemaic astronomy, celestial mechanics
Works: Book of Optics, Doubts Concerning Ptolemy, On the Configuration of the World, The Model of the Motions, Treatise on Light, Treatise on Place
Influences: Aristotle, Euclid, Ptolemy, Galen, Muhammad, Banū Mūsā, Thabit ibn Qurra, al-Kindi, Ibn Sahl, al-Qūhī
Influenced: Khayyam, al-Khazini, Averroes, Roger Bacon, Witelo, Pecham, Farisi, Theodoric, Gersonides, Alfonso, von Peuerbach, Taqi al-Din, Risner, Clavius, Kepler, John Wallis, Saccheri
Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haytham (Arabic: ابو علی، حسن بن حسن بن الهيثم, Persian: ابن هیثم, Latinized: Alhacen or (deprecated) Alhazen) (965 in Basra - c. 1039 in Cairo), was an Arab[2] or Persian[3] polymath.[4] He made significant contributions to the principles of optics, as well as to anatomy, astronomy, engineering, mathematics, medicine, ophthalmology, philosophy, physics, psychology, visual perception, and to science in general with his introduction of the scientific method. He is sometimes called al-Basri (Arabic: البصري), after his birthplace in the city of Basra.[5] He was also nicknamed Ptolemaeus Secundus ("Ptolemy the Second")[6] or simply "The Physicist"[7] in medieval Europe.
Born circa 965, in Basra, part of present-day Iraq and part of Buyid Persia at that time,[1] he lived mainly in Cairo, Egypt, dying there at age 76.[6] Over-confident about practical application of his mathematical knowledge, he assumed that he could regulate the floods of the Nile.[8] After being ordered by Al-Hakim bi-Amr Allah, the sixth ruler of the Fatimid caliphate, to carry out this operation, he quickly perceived the impossibility of what he was attempting to do, and retired from engineering. Fearing for his life, he feigned madness[1][9] and was placed under house arrest, during and after which he devoted himself to his scientific work until his death.[6]
Ibn al-Haytham is regarded as the "father of modern optics"[10] for his influential Book of Optics (written while he was under house arrest), which correctly explained and proved the modern intromission theory of vision. He is also recognized so for his experiments on optics, including experiments on lenses, mirrors, refraction, reflection, and the dispersion of light into its constituent colours.[11] He studied binocular vision and the Moon illusion, described the finite speed[12][13] of light, and argued that it is made of particles[14] travelling in straight lines.[13][15] Due to his formulation of a modern quantitative and empirical approach to physics and science, he is considered the pioneer of the modern scientific method[16][17] and the originator of the experimental nature of physics[18] and science.[19] Author Bradley Steffens describes him as the "first scientist".[20] He is also considered by A. I. Sabra to be the founder of experimental psychology[21] for his approach to visual perception and optical illusions,[22] and a pioneer of the philosophical field of phenomenology or the study of consciousness from a first-person perspective. His Book of Optics has been ranked with Isaac Newton's Philosophiae Naturalis Principia Mathematica as one of the most influential books in the history of physics,[23] for starting a revolution in optics[24] and visual perception.[25]
Ibn al-Haytham's achievements include many advances in physics and mathematics. He gave the first clear description[26] and correct analysis[27] of the camera obscura. He enunciated Fermat's principle of least time and the concept of inertia (Newton's first law of motion),[28] and developed the concept of momentum.[29] He described the attraction between masses and was aware of the magnitude of acceleration due to gravity at-a-distance.[30] He stated that the heavenly bodies were accountable to the laws of physics and also presented a critique and reform of Ptolemaic astronomy. He was the first to state Wilson's theorem in number theory, and he formulated the Lambert quadrilateral[31] and a concept similar to Playfair's axiom[32] now used in non-Euclidean geometry. Moreover, he formulated and solved Alhazen's problem geometrically using early ideas related to calculus and mathematical induction.[33] In his optical research, he laid the foundations for the later development of telescopic astronomy,[34] as well as for the microscope and the use of optical aids in Renaissance art.[35]
Overview
Biography
Abū ‘Alī al-Hasan ibn al-Hasan ibn al-Haytham (and known in Europe as Alhacen or Alhazen) was born in Basra in present-day Iraq, </ref>. He probably died in Cairo, Egypt. During the Islamic Golden Age, Basra was a "key centre of learning",[36] and he was educated there and in Baghdad, the capital of the Abbasid Caliphate, and the focus of the "high point of Islamic civilization".[36] During his time in Iraq, he worked as a civil servant and read many theological and scientific books.[5]
One account of his career has him summoned to Egypt by the mercurial Al-Hakim bi-Amr Allah, ruler of the Fatimid Caliphate, to regulate the flooding of the Nile, a task requiring an early attempt at building a dam at the present site of the Aswan Dam.[37] After his field work made him aware of the impracticality of this scheme,[6] and fearing the caliph's anger, he feigned madness. He was kept under house arrest from 1011 until al-Hakim's death in 1021.[38] During this time, he wrote his influential Book of Optics.
Although there are stories that Ibn al-Haytham fled to Syria, ventured into Baghdad later in his life, or was even in Basra when he pretended to be insane, it is certain that he was in Egypt by 1038 at the latest.[5] During his time in Cairo, he became associated with Al-Azhar University, as well the city's "House of Wisdom",[39] known as Dar Al-Hekma (House of Knowledge), which was a library "second in importance" to Baghdad's House of Wisdom.[5] After his house arrest ended, he wrote scores of other treatises on physics, astronomy and mathematics. He later traveled to Islamic Spain. During this period, he had ample time for his scientific pursuits, which included optics, mathematics, physics, medicine, and the development of scientific methods; he left several outstanding books on these subjects.