Ibn al-Haytham (Alhazen)

Known for

Book of Optics; explained vision by light entering the eye; pioneer of the experimental method

Biography

Arab scientist from Basra (Iraq) who did most of his work in Fatimid Cairo.

Contributions

• Showed that we see because light from objects enters the eye, not rays sent out from the eye
• Studied reflection, refraction and the camera obscura (pinhole camera) with experiments
• Insisted on testing theories by controlled, repeatable experiments, an early form of the scientific method
• Criticized Ptolemy's astronomy in Doubts Concerning Ptolemy

Major works

• Kitab al-Manazir (Book of Optics)
• Al-Shukuk 'ala Batlamyus (Doubts Concerning Ptolemy)