Al-Hazen: Arab mathematician

Book of Optics or Kitab al-Manazir, was written by Abū ‘Alī al-Ḥasan ibn al-Ḥasan ibn al-Haytham (965–1039 AD).

Abū ‘Alī al-Ḥasan ibn al-Ḥasan ibn al-Haytham or Ibn al-Haytham in brief, commonly known as Alhazen (also spelled Alhacen) in the Western literature, was an Arab Islamic polymath, physician, astronomer, mathematician, physicist and philosopher.

Ibn al-Haytham was born in Basra of Old Persia (now southern Iraq) in about 965 AD. His birthplace also resulted in him being known as al-Basri. Ibn alHaytham spent his primary education in his native city and continued his education in Baghdad (currently the capital city of Iraq). Ibn al-Haytham became a government minister (vizier) in Basra and spent his spare time working on mathematics, writing a treatise on the ancient (and impossible) problem of squaring the circle.

His work in optics irrefutably proved that vision is a function of external light rays entering the human eye; his rigorous and quantitative approach formed the basis of the modern experimental method in science.

Ibn al-Haytham was the first person to firmly reject the extramission theory of vision. In contrast to the popular theories of his predecessors, including those of Galen (130–200 AD), Ptolemy (died 178 AD) and Euclid (330– 260 BC), Ibn al-Haytham believed that objects are seen by light rays emanating from the objects and not from the eyes.

Ibn al‐Haytham's mathematical research was particularly in the field of geometry and not of algebra. The contributions of Ibn al‐Haytham in geometry can be divided into several groups, the most important of which are in infinitesimal mathematics and the theory of conic sections and their applications. He composed 12 treatises on infinitesimal mathematics and then on conic theory.

Ibn al-Haytham was a prolific author. Ibn Abi Usaibi’a attributed more than 200 works to Ibn al-Haytham, covering a wide variety of philosophical and scientific matters including medicine, mathematics, astronomy, physics, optics and vision, cosmology, meteorology and metaphysics.

One of Ibn al-Haytham 's most significant creations was a seven-volume work on optics titled Kitab al-Manazir (later translated to Latin as Opticae Thesaurus Alhazeni – Alhazen's Book of Optics). Al-
Hazen: Arab mathematician 

Book of Optics (Opticae Thesaurus) by Al-Hazen

Abū ‘Alī al-Ḥasan ibn al-Ḥasan ibn al-Haytham conducted research in optics, mathematics, physics, medicine and development of scientific methods. His mainwork, The Book of Optics, was writtenwhile under house arrest in Cairo during eleven years 1010-1021. Abū ‘Alī al-Ḥasan ibn al-Ḥasan ibn al-Haytham was regarded as the father of Modern Optics.

The Arab Muslim scholar Abu Ali al Hasan ibn al-Haytham , known in the west as Al-Hacen or Al-Hazen was born in 965 in the city of Basra in Southern Iraq, hence he is also known as Al-Basri. He was educated in Basra and Baghdad, and died in Cairo, Egypt in the year 1040.

He wrote more than 200 works on a wide range of subjects, of which at least 96 of his scientific works are known, and approximately 50 of them have survived to date.

Al-Hazen was an expert and a serious researcher in philosophy, physics and mathematics. He is considered the most important researcher in optics between antiquity and the seventh century. He made a significant contribution to understanding of the visual process and systemically investigated the optical properties of air.

In the book Al-Hazen correctly explained and proved modern intromission theory of vision. He recognized for his experimentation on optics, including experiment on lenses, mirror, refraction, reflection and the dispersion of light into its constituent colors. He studied binocular vision and the Moon illusion, described the finite speed of light, and argued that it is made of particles traveling in straight lines. Due to his formulation of a modern quantitative and empirical approach to physics and science, he is considered the pioneer of the modern scientific method and the originator of the experimental nature of physics and science.

Al-hazen described the eye and its functioning, and he made mathematical descriptions of the properties of light. He proposed that light moves with finite speed, and that it moves more slowly in dense media.

In his Kitab al-Manazir, Al-Hazen asserted that optics is a synthetic branch of inquiry that combines mathematical and physical consideration. This not only a new doctrine of vision, but also a new methodology. Al-Hazen was led to formulate problems which either would not have made sense from the stand point of the visual-ray theory or had been ignored by philosophers aiming primarily to give an account of what vision rather than an explanation of how to take place.

Al-Haytham was the pioneer of the modern scientific method. With his book, he changed the meaning of the term “optics”, and established experiments as the norm of proof in the field.

For reason that are not entirely clear, the Kitab al-Manazir seems to have been virtually unknown in the Islamic world until the end of the thirteenth century. Only then did the Arabic text receive the attention it deserved in the form of a critical commentary written in Arabic by the Persian Kamal al-Din al-Farisi. The Book of Optics was translated into Latin, and had much influence especially on and through Roger Bacon.

Some parts of the Book of Optics came to Europe about 1200, were translated into Latin, and had great impact on the development of European science in the following centuries. Alhazen's book was considered the most important book on optics until Johannes Kepler's "Astronomiae Pars Optica" from 1604.
Book of Optics (Opticae Thesaurus) by Al-Hazen