In 1011, the caliph of Egypt appointed a young civil servant to design and construct a huge dam across the Nile River. Every year, flooding disrupted the country’s agriculture, and the caliph hoped that a barrier might prevent the annual deluge. The man he picked for the task, Ibn al-Haytham (965–c. 1040), was renowned as one of the most promising mathematicians of the Islamic world.
After arriving at the proposed dam site, however, al-Haytham quickly realized that the caliph’s dream was completely impractical. The Nile, one of the most powerful rivers in the world, would wash away any dam within days. But al-Haytham feared that the caliph, who was known for his cruelty and eccentric behavior, would punish him if he failed to carry out his mission.
Luckily for science, al-Haytham found a way to avoid the caliph’s wrath: For the next ten years, he pretended to be insane. He was placed under house arrest, but his life was spared. And while he was in captivity, al-Haytham wrote one of the pivotal works in the history of science, Optics.
Al-Haytham was born in the Iraqi city of Basra and educated in Baghdad. Seven volumes in length, Optics was a massive inquiry into the behavior of light and the workings of the human eye. Al-Haytham was the first to discover that light moves in a straight line, the first to devise a camera obscura, and the first to deduce how the eye functions. The book was also notable for al-Haytham’s reliance on experimentation, an emphasis that helped inspire the scientific method. Optics became a favorite of European scholars such as Roger Bacon (c. 1214–c. 1292) after it was translated into Latin in the twelfth century, and it earned its author the title “father of optics.”
After the assassination of the caliph in 1021, al-Haytham was finally released from house arrest. For the rest of his life, he continued to experiment—he wrote some 200 books on physics, astronomy, and medicine—while earning a living by producing handwritten copies of other books. He died in Egypt in his seventies.