Who was Ibn-al-Haytham? Everything You Need to Know

Quick Facts

Nick Name: Alhazen, al-Basri,

Also Known As: Ḥasan Ibn al-Haytham, Alhazen

Died At Age: 75

Born Country: Iraq

Physicists Astronomers

Died on: 1040

place of death: Cairo, Egypt

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1

What were Ibn al-Haytham's significant contributions to the field of optics?

Ibn al-Haytham made significant contributions to the field of optics, particularly in understanding the nature of light, vision, and the principles of reflection and refraction. His work laid the foundation for modern optics and the scientific method.
2

How did Ibn al-Haytham's work influence the development of the scientific method?

Ibn al-Haytham's work on optics and his emphasis on experimental investigation and evidence-based reasoning had a profound impact on the development of the scientific method. He is considered one of the pioneers of the scientific method.
3

How did Ibn al-Haytham challenge the prevailing theories of vision in his time?

Ibn al-Haytham challenged the prevailing theories of vision in his time by arguing that vision is not a result of light emitted from the eyes, but rather light entering the eyes. His experimental approach and observations revolutionized the understanding of vision.
4

What is the significance of Ibn al-Haytham's concept of the camera obscura?

Ibn al-Haytham's concept of the camera obscura, a darkened room with a small hole through which light enters to project an inverted image, was a precursor to the development of photography. His experiments with the camera obscura helped advance the understanding of light and vision.

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Childhood

Ibn-al-Haytham was born in the city of Basra in Southern Iraq (which was then under the Buyid Emirate), around 965 CE.

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Overview of Life

After completing his formal education in Basra, he relocated to Cairo, Egypt then ruled by Al-Hakim, the Fatimid Caliph who patronized the sciences, especially astronomy.

It is said that Ibn-Al-Haytham made a proposal to the Caliph to construct a weir (at the same location where Aswan Dam stands today) in order to tame the tumultuous Nile. However, historians and chroniclers are at variance regarding the veracity of the above proposition.

It later dawned on al-Haytham that building a dam over the river may not prevent the waterway from flooding its banks. However, he was terrified of revealing the truth to Al-Hakim who was notorious for his irrational ways and therefore in order to save himself from getting executed, he pretended to be insane.

Al-Haytham was detained in his house from 1011 to 1021, till Al-Hakim died. It was during his detention that he penned the seminal ‘Book of Optics’ which is considered his masterpiece, and also authored pieces on astronomy, philosophy, number theory, and geometry.

Legacy &Influences

Ibn-al-Haytham not only pioneered new theories, concepts, and postulates in geometry, astronomy, natural philosophy, and arithmetic but also gave fresh insight to these disciplines by correcting erroneous propositions believed to be hitherto flawless. However, his most noteworthy contributions were in optics, a branch of physics, and it is epitomized by his magnum opus, the ‘Kitab al-Manazir’.

He was perhaps the first researcher and scientist to stress on the imperativeness of proving a hypothesis or theorem through experiments using scientific methods. In the past, academics and scholars banked on reason and divinity for substantiating a proposition or concept.

Al-Haytham drew inspiration from several Greek, Persian, and Turkish scholars including Aristotle, Ptolemy, Euclid, Pythagoras, Galen, Abu Sahl al-Quhi, Ibn Sahl, Al-Kindi, Thabit Ibn Qurra, and Banu Musa for his observations.

His works influenced luminaries like Averroes, Omar Khayyam, Taqi-ad-din Muhammad Ibn Mar’uf, Kamal al-din al-Farisi, Johannes Kepler, and Roger Bacon.

Kitab-al-Manazir (Book of Optics)

’Kitab-al-Manazari’, a seven-tome compilation on optics was Al-Haytham’s most notable work written over a period of ten years. The credit for revealing the significance of this encyclopedic work in the Muslim dominions goes to Kamal al-din al-Farisi, the 13th century Persian scientist who made commentaries on the work.

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Al-Haytham endeavored to strike a balance between two key postulates on vision that prevailed in the Greco-Roman world. The primary proposition, ‘Emission Theory’ propounded by Ptolemy and Euclid, stressed that the eyes emitted light rays resulting in the perception of vision.

The second hypothesis, the ‘Intromission Theory’ backed by Aristotle hinted that light bounced off of different subjects and objects to enter the eye making visualization possible. Al-Haytham drew heavily from Ptolemy’s ‘Optics’, Euclid, and Aristotle as well as cited Galen for describing the eye’s physiology and anatomy.

He commented that light rays hit the eyes after rebounding from objects and not the other way round as the sight organs experienced pain when an individual looked at the sun directly. He refuted the assertion that the eyes sent out beams of light.

Light rays of different colors given off by self-illuminating transparent bodies and opaque sources are picked up by the eyes when they lie in the line of sight. The incident rays form an impression in the eyes’ glacial humor is interpreted by the mind as vision or sight enabling the individual to see.

The above supposition which formed the crux of Al-Haytham’s vision theory became the cornerstone for all future discussions and debates on optics in the countries of Europe till the 17th century

The Scientific Analysis

Al-Haytham relied heavily on supervised testing and systematic experiments to back up his researches and investigations he undertook in the aforementioned academic disciplines. The practice of using methodical experimentations in a consistent and even manner for establishing the legitimacy of propositions was pioneered by him.

Alhazen's

Al-Haytham’s discussed at length on catoptrics—a section of optics dealing with light reflections from mirrors or objects with mirror-like surfaces—in volume 5 of ‘Kitab-al-Manazari’ that was termed as ‘Alhazen’s problem. It was Ptolemy, the Greek polymath who first dabbled in catoptrics in 150 A.D.

Al-Haytham analyzed the intricacies involved with reflections from different types of mirrors and mirror-like objects in his own way. He dealt with the catoptrics problem by attempting to work out the point and angle of reflection from curved or plane surfaces when the observer was focusing on an object.

Al-Haytham analogized the catoptrics predicament first propounded by Ptolemy diagrammatically and solved it geometrically using conic representations. His other important optical contributions include ‘A Discourse on Light’, ‘On the Shape of the Eclipse’, ‘On Halo and Rainbow’, and ‘On the Light of the Moon’.

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Other Works on Physics

Al-Haytham touched space physics which can be found in his treatise ‘Epitome of Astronomy’ and maintained that Ptolemaic astronomy models could be correlated with physical objects for understanding them. He also explored ‘mechanics’ another branch of physics discussing in detail about the different forces acting on a body that creates motion.

Facts About Ibn-al-Haytham

Ibn al-Haytham was a pioneer in the field of optics and is often referred to as the "father of modern optics" for his groundbreaking work on the nature of light and vision.

He is credited with introducing the scientific method to the field of optics, emphasizing the importance of experimentation and observation in understanding the natural world.

Ibn al-Haytham's influential work, the "Book of Optics," was a key text in the development of the scientific revolution in Europe and had a significant impact on the study of optics for centuries to come.

In addition to his scientific contributions, Ibn al-Haytham was also a talented polymath, with interests and expertise in a wide range of fields including mathematics, astronomy, and engineering.

Despite living in the 10th and 11th centuries, Ibn al-Haytham's ideas and methods continue to inspire scientists and researchers today, making him a truly timeless figure in the history of science.

Works on Astronomy

Al-Haytham’s works on astronomy have contributed greatly towards the development of this specific branch of science. He offered a comprehensive account of the earth’s physical structure and composition in ‘On the Configuration of the World’. In ‘Doubts Concerning Ptolemy’ he indicated and specified several incongruities in Ptolemy’s works including ‘Almagest’, ‘Optics’, and ‘Planetary Hypotheses’.

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He wrote another book on astronomy, titled ‘The Model of the Motions of Each of the Seven Planets’ in c. 1038. He authored 25 volumes on astronomy that basically centered on astronomical observations, problems, and technical issues.

Works on Mathematics

Al-Haytham carried forward the mathematical postulates of Thabit Ibn Qurra and Euclid, especially on “the beginnings of the link between algebra and geometry”. He recorded his observations on ‘Euclidean parallel postulate’ and created the ‘Lambert quadrilateral’ also called ‘Ibn-Al-Haytham-Lambert quadrilateral’. He tried to find a solution to how to square a circle.

He experimented on ‘perfect numbers’ in his mathematical project named, ‘Analysis and Synthesis’. He solved the Wilson’s Theorem’ in another mathematical project called ‘Opuscula’. He also made significant contributions to ‘Calculus’ including the summation equation for the 4th power which helped him in determining a paraboloid’s volume.

Other Works & Contributions

Apart from making constructive and groundbreaking contributions to mathematics, astronomy, optics, physics, and geometry, Al-Haytham also forayed into engineering, philosophy, and theology. He conducted an in-depth analysis of the Nile’s deluging its banks and laid out a blueprint for constructing a dam over the river.

He penned ‘Treatise on Place’ where he refuted the Aristotlean philosophy that Nature was not vacuous. He attempted to demonstrate geometrically that it (Nature) was actually void, similar to the presumed 3-dimensional emptiness within a body’s inner surfaces.

Al-Haytham was a staunch follower of the Islam faith and wrote a book based on Islamist theology that elaborated on prophethood and listed a set of idealistic criterions to discourage phoney candidates pretending to be oracles.

Death

Ibn al-Haytham died around c. 1040, in Cairo, Fatimid Caliphate.

He did not get the credit that was due to him on account of his works that covered a wide variety of academic disciplines and topics. Nevertheless, it would not be an exaggeration to state that the quintessential polymath’s diverse body of work has inspired researchers, scholars, and intellectuals who followed him.

Ibn-al-Haytham Biography

You wanted to know

What were Ibn al-Haytham's significant contributions to the field of optics?

How did Ibn al-Haytham's work influence the development of the scientific method?

How did Ibn al-Haytham challenge the prevailing theories of vision in his time?

What is the significance of Ibn al-Haytham's concept of the camera obscura?