Episode Details

Summoned to dam the Nile by the volatile Fatimid caliph al-Hakim, the engineer Ibn al-Haytham realized the project was impossible and faked madness to save his life. This deep dive explores how roughly a decade of house arrest in Cairo produced his seven-volume Book of Optics and a new standard for proving ideas through experiment.

We follow his path from theology in Basra to mathematics and engineering, then examine how he overturned the ancient emission and intromission theories of vision, argued that perception happens in the brain, and used controlled experiments with the camera obscura. We also cover his work on reflection and refraction and how Latin translations shaped Kepler, Galileo, and Descartes.

• Why he turned from theology to mathematics in search of certainty
• The perpendicular ray idea and his ball-against-a-board analogy
• Candles outside a dark room proving that light travels in straight lines
• Finite light speed, refraction, and an early version of the principle of least time
• How De aspectibus spread his work and why Europeans called him simply the physicist