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Wednesday, June 1, 2011



Abu Ali al-Hasn ibn al-Haytham:
Born: 965 (possibly) Basra, Persia (now Iraq)
Died: 1040 (possibly) Cairo, Egypt

Abu Ali al-Hasan ibn al-Hasan ibn al-Haytham was the pioneer scientist who initiated the scientific revolution over 1000 years ago. He was the first person to test hypotheses with verifiable experiments, developing the scientific method more than 200 years before European scholars learned of it, by reading his books. He is often known as Alhazen which is the Latinised version of his first name "al-Hasan".
In particular this name occurs in the naming of the problem for which he is best remembered, namely Alhazen's problem:

Given a light source and a spherical mirror, find the point on the mirror were the light will be reflected to the eye of an observer.

A devout Muslim, Ibn al-Haitham believed that  

human beings are flawed and only God is perfect. To discover the truth about nature, Ibn a-Haitham reasoned, one had to eliminate human opinion and allow the universe to speak for itself through physical experiments. 

"The seeker after truth is not one who studies the writings of the ancients and, following his natural disposition, puts his trust in them, but rather the one who suspects his faith in them and questions what he gathers from them, the one who submits to argument and demonstration."

Ibn Al-Haytham - The First Scientist - Origin of the Camera

Since the main events that we know of in ibn al-Haytham's life involve his time in Egypt, we should set the scene regarding that country. The Fatimid political and religious dynasty took its name from Fatimah, the daughter of the Prophet Muhammad. The Fatimids headed a religious movement dedicated to taking over the whole of the political and religious world of Islam. As a consequence they refused to recognise the 'Abbasid caliphs. The Fatimid caliphs ruled North Africa and Sicily during the first half of the 10th century, but after a number of unsuccessful attempts to defeat Egypt, they began a major advance into that country in 969 conquering the Nile Valley. They founded the city of Cairo as the capital of their new empire. These events were happening while ibn al-Haytham was a young boy growing up in Basra
We know little of ibn al-Haytham's years in Basra. In his autobiography he explains how, as a youth, he thought about the conflicting religious views of the various religious movements and came to the conclusion that none of them represented the truth. It appears that he did not devote himself to the study of mathematics and other academic topics at a young age but trained for what might be best described as a civil service job.

He was appointed as a minister for Basra and the surrounding region. However, ibn al-Haytham became increasingly unhappy with his deep studies of religion and made a decision to devote himself entirely to a study of science which he found most clearly described in the writings of Aristotle. Having made this decision, ibn al-Haytham kept to it for the rest of his life devoting all his energies to mathematics, physics, and other sciences.

Ibn al-Haytham went to Egypt some considerable time after he made the decision to give up his job as a minister and to devote himself to science, for he had made his reputation as a famous scientist while still in Basra. We do know that al-Hakim was Caliph when ibn al-Haytham reached Egypt. Al-Hakim was the second of the Fatimid caliphs to begin his reign in Egypt; al-Aziz was the first of the Fatimid caliphs to do so. Al-Aziz became Caliph in 975 on the death of his father al-Mu'izz. He was very involved in military and political ventures in northern Syria trying to expand the Fatimid empire. For most of his 20 year reign he worked towards this aim. Al-Aziz died in 996 while organising an army to march against the Byzantines and al-Hakim, who was eleven years old at the time, became Caliph.

Al-Hakim, despite being a cruel leader who murdered his enemies, was a patron of the sciences employing top quality scientists such as the astronomer ibn Yunus. His support for science may have been partly because of his interest in astrology. Al-Hakim was highly eccentric, for example he ordered the sacking of the city of al-Fustat, he ordered the killing of all dogs since their barking annoyed him, and he banned certain vegetables and shellfish. However al-Hakim kept astronomical instruments in his house overlooking Cairo and built up a library which was only second in importance to that of the House of Wisdom over 150 years earlier.
Our knowledge of ibn al-Haytham's interaction with al-Hakim comes from a number of sources, the most important of which is the writings of al-Qifti. We are told that al-Hakim learnt of a proposal by ibn al-Haytham to regulate the flow of water down the Nile. He requested that ibn al-Haytham come to Egypt to carry out his proposal and al-Hakim appointed him to head an engineering team which would undertake the task. However, as the team travelled further and further up the Nile, ibn al-Haytham realised that his idea to regulate the flow of water with large constructions would not work.

Ibn al-Haytham returned with his engineering team and reported to al-Hakim that they could not achieve their aim. Al-Hakim, disappointed with ibn al-Haytham's scientific abilities, appointed him to an administrative post. At first ibn al-Haytham accepted this but soon realised that al-Hakim was a dangerous man whom he could not trust. It appears that ibn al-Haytham pretended to be mad and as a result was confined to his house until after al-Hakim's death in 1021.

During this time he undertook scientific work and after al-Hakim's death he was able to show that he had only pretended to be mad. According to al-Qifti, ibn al-Haytham lived for the rest of his life near the Azhar Mosque in Cairo writing mathematics texts, teaching and making money by copying texts. Since the Fatimids founded the University of Al-Azhar based on this mosque in 970, ibn al-Haytham must have been associated with this centre of learning.
A different report says that after failing in his mission to regulate the Nile, ibn al-Haytham fled from Egypt to Syria where he spent the rest of his life. This however seems unlikely for other reports certainly make it certain that ibn al-Haytham was in Egypt in 1038. One further complication is the title of a work ibn al-Haytham wrote in 1027 which is entitled Ibn al-Haytham's answer to a geometrical question addressed to him in Baghdad. Several different explanations are possible, the simplest of which being that he visited Baghdad for a short time before returning to Egypt. He may also have spent some time in Syria which would partly explain the other version of the story. Yet another version has ibn al-Haytham pretending to be mad while still in Basra.

According to medieval biographers, Ibn al-Haytham wrote more than 200 works on a wide range of subjects,[23] of which at least 96 of his scientific works are known. Most of his works are now lost, but more than 50 of them have survived to some extent. Nearly half of his surviving works are on mathematics, 23 of them are on astronomy, and 14 of them are on optics, with a few on other areas of science.[24] Not all of his surviving works have yet been studied, but some of his most important ones are described below. These include:
  • Book of Optics (1021)
  • Analysis and Synthesis
  • Balance of Wisdom
  • Discourse on Place
  • Maqala fi'l-qarastun
  • Doubts concerning Ptolemy (1028)
  • On the Configuration of the World
  • Opuscula
  • The Model of the Motions of Each of the Seven Planets (1038)
  • The Resolution of Doubts
  • Treatise on Light
  • Treatise on Place

Scientific method

Rosanna Gorini wrote the following on Ibn al-Haytham's introduction of the scientific method:
"According to the majority of the historians 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. His investigations are based not on abstract theories, but on experimental evidences and his experiments were systematic and repeatable."[9]
Roshdi Rashed wrote the following on Ibn al-Haytham:
"His work on optics, which includes a theory of vision and a theory of light, is considered by many to be his most important contribution, setting the scene for developments well into the seventeenth century. His contributions to geometry and number theory go well beyond the archimedean tradition. And by promoting the use of experiments in scientific research, al-Haytham played an important part in setting the scene for modern science."[24]
Ibn al-Haytham developed rigorous experimental methods of controlled scientific testing in order to verify theoretical hypotheses and substantiate inductive conjectures.[17] Ibn al-Haytham's scientific method was very similar to the modern scientific method and consisted of the following procedures:[23]
  1. Observation
  2. Statement of problem
  3. Formulation of hypothesis
  4. Testing of hypothesis using experimentation
  5. Analysis of experimental results
  6. Interpretation of data and formulation of conclusion
  7. Publication of findings
In The Model of the Motions, Ibn al-Haytham also describes an early version of Occam's razor, where he employs only minimal hypotheses regarding the properties that characterize astronomical motions, as he attempts to eliminate from his planetary model the cosmological hypotheses that cannot be observed from Earth
Article by: J J O'Connor and E F Robertso

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