Spotlight on the 11th-century pioneer of optics and scientific experimentation
Born around a thousand years ago in present day Iraq, Al-Hasan Ibn al-Haytham (known in the West by the Latinised form of his first name, initially “Alhacen” and later “Alhazen”) was a pioneering scientific thinker who made important contributions to the understanding of vision, optics and light. His methodology of investigation, in particular using experiment to verify theory, shows certain similarities to what later became known as the modern scientific method. Through his Book of Optics (Kitab al-Manazir) and its Latin translation (De Aspectibus), his ideas influenced European scholars including those of the European Renaissance. Today, many consider him a pivotal figure in the history of optics and the “Father of modern Optics” (see references below).
Ibn al-Haytham was born during a creative period known as the golden age of Muslim civilisation that saw many fascinating advances in science, technology and medicine. In an area that spread from Spain to China, inspirational men and women, of different faiths and cultures, built upon knowledge of ancient civilisations, making discoveries that had a huge and often underappreciated impact on our world.
In January 2015, 1001 Inventions launched a high-profile international educational campaign and transmedia initiative celebrating Ibn al-Haytham. The global campaign ‘1001 Inventions and the World of Ibn al-Haytham’ is produced by the UK based, science and cultural heritage organization, 1001 Inventions and Saudi Aramco’s King Abdulaziz Center for World Culture, in partnership with UNESCO and the United Nations International Year of Light and Light-based Technologies (IYL 2015), celebrating the central role of light in science and culture.
Ibn al-Haytham's work was remarkable for its emphasis on proof and evidence. He is known to have said:
“If learning the truth is the scientist’s goal… then he must make himself the enemy of all that he reads. ”By this he meant it was essential to conduct experiments to test what is written rather than blindly accepting it as true.
Ibn al-Haytham was born in the year 965 in Basra, and died in about 1040 in Cairo. He was one of the earliest scientists to study the characteristics of light and the mechanism/process of vision. He sought experimental proof of his theories and ideas. During many years living in Egypt, ten of which were spent underwhat we may now call protective custody (house arrest), he composed one of his most celebrated works, the Kitab al-Manazir, whose title is commonly translated into English as Book of Optics but more properly has the broader meaning Book of Vision.
Ibn al-Haytham made significant advances in optics, mathematics and astronomy. His work on optics was characterised by a strong emphasis on carefully designedexperiments to test theories and hypotheses. In that regard he was following a procedure somewhat similar to the one modern scientists adhere to in their investigative research.
Different views about how the process of vision could be explained had been in circulation for centuries mainly among classical Greek thinkers. Some said rays came out of the eyes, while others thought something entered the eyes to represent an object. But it was the 11th-century scientist Ibn al-Haytham who undertook a systematic critique of these ideas about vision in order to demonstrate by both reason and experiment that light was a crucial, and independent, part of the visual process. He thus concluded that vision would only take place when a light ray issued from a luminous source or wasreflected from such a source before it entered the eye.
Ibn al-Haytham is credited with explaining the nature of light and vision, through using a dark chamber he called “Albeit Almuzlim”, which has the Latin translation as the “camera obscura”; the device that forms the basis of photography.
Out of the 96 books he is recorded to have written; only 55 are known to have survived. Those related to the subject of light included: The Light of the Moon, The Light of the Stars, The Rainbow and the Halo, Spherical Burning Mirrors, Parabolic Burning Mirrors, The Burning Sphere, The Shape of the Eclipse, The Formation of Shadows, Discourse on Light, as well as his masterpiece, Book of Optics. Latin translations of some of his works are known to have influenced important Medieval and European Renaissance thinkers like Roger Bacon, René Descartes and Christian Huygens, who knew him as “Alhazen”. The crater Alhazen on the Moon is named in his honour, as is the asteroid 59239Alhazen.
- Born in 965 in Basra, during the intellectual heyday of Muslim civilisation
- Invited to Egypt to help build a dam on the Nile. After a field visit, he declined to proceed with the project causing him to end up in what we now call -protective custody for 10 years.
- From his observations of light entering a dark room, he made major breakthroughs in understanding light and vision
- His discoveries led him to make significant revision to ancient views about how our eyes see.
- Through his studies of earlier work by Galen and others, he gave names to several parts of the eye, such as the lens, the retina and the cornea.
- He set new standards in experimental science and completed his great Book of Optics sometime around 1027.
- He died at the age of 74 in around the year 1040
- His Book of Optics was translated into Latin and had a significant influence on many scientists of the Middle Ages, Renaissance and Enlightenment. For example, the optics book Perspectiva was authored around 1275 byErazmus Witelo, who later was called "Alhazen's Ape" when people realised he had largely copied al-Haytham’s Book of Optics.