Ptolemy the Second: Alhazen
Abu Ali Hasan Ibn al-Haitham (anglicized as Alhazen) was an Arabic scientist who, like al-Khwarizmi, proved to be prolific for the field of science at a time when European scientists were making few contributions. While many details of his life are lost to history, Alhazen’s work paints the picture of an incredible, scientific mind. Born in 965 in Basra, Iraq, Alhazen was on the path to becoming a religious scholar or minister when he decided to pursue his interest in science instead. Interestingly enough, much of Alhabzen’s later work would challenge the theories of Aristotle, Ptolemy, and Euclid that he studied before conducting his own experiments. Alhazen favored the study of optics, experimenting with refraction, dispersion of light into component colors, catoptrics (the function of mirrors in optics), and shadows and eclipses. He was nearly successful in accurately describing the laws of refraction, which took another three hundred years to be perfected. Kitab-al-Manadhir, known as Book of Optics in English, was his most influential work and the result of ten years of writing and experimentation. One development from this text was Alhazen’s theory of light. According to his theory, sources such as the sun or fire emanate light, which reflects off of objects before being received by the eyes. Alhazen’s concept of light contradicted the theories of Ptolemy and Euclid which argued that light was emitted from the eyes. Alhazen’s theory was very much revolutionary, rejecting ideas that had been accepted by the scientific community for hundreds of years.
Alhazen’s method of disproving the prevailing view of light was equally groundbreaking. Unlike the Classical Greek scientists preceding him and even the scientists succeeding him, Alhazen generated an observation-derived hypothesis and created a rigorous experiment to determine the validity of his claims. Alhazen’s use of the scientific method sets him apart from other early scientists, and the Latin translation of his Book of Optics and its emphasis on the scientific method held great influence over Roger Bacon and Johannes Kepler.
In addition to researching optics, Alhazen studied other fields with equally significant results. His adherence to the scientific method led him to become one of the first scientists to reject astrology as an empirically invalid field. Alhazen also formulated a precursor of Newton’s First Law of Motion. His work in optics and other fields earned him the nicknames Ptolemaeus Secundus (Ptolemy the Second) and the “Father of Physics” during the Middle Ages. Alhazen, in conjunction with other Islamic scientists, made significant contributions towards the study of science. Their hundreds of years of work, translated into Latin and widely distributed throughout Europe, would eventually become the intellectual foundation of the Renaissance.
Vijay Venkatesan is a freshman from Baker College at Rice University.