Alhazen (Ibn al-Haytham)

Al-Hasan Ibn al-Haytham (c. 965–1040 CE), celebrated in the West as Alhazen, was an intellectual giant who lived in Basra and Fatimid Cairo. Feigning madness to escape execution by the erratic Caliph al-Hakim after recognizing the impossibility of damming the Nile with 11th-century engineering, he was placed under house arrest for ten years, which he used to conduct groundbreaking optical experiments.

In his monumental seven-volume Kitab al-Manazir (*Book of Optics*), he demolished the ancient extramission theory of Euclid and Ptolemy, proving through dark-chamber experiments (*al-bayt al-muzlim*, camera obscura) that light reflects from external objects into the eye. He established the modern scientific method: systematically testing hypotheses through repeatable empirical experiment.