Ibn al-Haytham

Abu Ali al-Hasan ibn al-Haytham (354-430 AH / 965-1040 CE), known in the West as Alhazen, was an Arab Muslim scientist who made groundbreaking contributions to optics, physics, mathematics, and astronomy. Born in Basra, he later moved to Cairo during the reign of the Fatimid caliph al-Hakim bi-Amr Allah, where he spent the most productive years of his career.

Ibn al-Haytham's most important work, Kitab al-Manazir (Book of Optics), revolutionized the understanding of vision and light. He definitively disproved the ancient Greek 'emission theory' (which held that eyes emit rays that enable vision) and established that vision occurs when light enters the eye from external objects. He conducted systematic experiments on the behavior of light, including reflection, refraction, and the camera obscura effect, making him one of the earliest practitioners of what we now call the scientific method: formulating hypotheses, designing experiments, observing results, and drawing conclusions. The Latin translation of his Book of Optics profoundly influenced European scientists including Roger Bacon, Johannes Kepler, and Isaac Newton.

Ibn al-Haytham authored over 200 works on optics, astronomy, mathematics, engineering, philosophy, and medicine, though many have been lost. His mathematical work included advances in number theory and analytic geometry. He died in Cairo in 430 AH (1040 CE). His emphasis on empirical evidence and systematic experimentation makes him one of the most important figures in the history of science, and his contributions are recognized as laying the groundwork for modern physics and the scientific method.