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Throughout human history civilizations experience periods of great intellectual growth: a golden age where scholarship greatly encourages the function and expansion of a civilization. The Muslim Caliphate, known for its great scientific advancements, was a particular civilization made multiple contributions to the world’s human knowledge and education. As Muhammad Saud once expressed, “Islam’s greatest contribution to human history is its sound and healthy concept of God, and a sound and healthy vision of life and society” (1). During the Muslim period of enlightenment, many great thinkers used the resources of their progressive culture to attribute findings in natural science and technology. One such man, known as Alhazen will make such remarkable advancements in the area of the natural sciences. He will later be recognized as one of the greatest scientists known in Islamic history. Alhazen’s empirical method revolutionized the scientific thinking/way to seek knowledge of his time and went on to influence the advancements of later science including seventeenth century Christian Europe.

The Muslim scholar Abu Ali al Hasan Ibn al-Haytham, (ca. 965-1040 CE) better known in Europe as Alhazen or Alhacen (the latin form of al Hasan) was born in the southern Iraq city of Basra. One might think that Alhazen was always a man of science but his early years led him towards another path. His father was a civil servant and Alhazen became well educated (Gorini 53). After completing his civil service education Alhazen was appointed chief minister of the caliphate of Basra. As a part of his role he was required to immerse himself in theological readings, and endless religious debates (Morgan 98).

Having the position of chief minister was a very prestigious role in the Muslim caliphate. After some time Alhazen began to question the arguments of theology he encountered, and wondered “how could something as vast and complicated as the divine be known with any certainty by the mortal mind” (Morgan 98). This was a forward thinking question Alhazen had posed to himself, and he knew, “that there was only a single truth and that the differences of opinions was the result of the different ways adopted to seek it” (Saud 3). Until now, truth was based upon information deduced from what was already known and then theorized upon. Alhazen believed that no man could merely understand the complexities of God and life just by speculating about such ideas. He resigned from his position of power as chief minister and sought to find truth through science. Having a civil service education established Alhazen as an intellectual man, however it is, “apparent from the titles of his own writings that he was widely read in Greek mathematics and mathematical science” (Lindberg 61). Many men would not have given up power for the life of a scholar yet, “the only thing that motivates him is the hunger to know more, to understand the complexity of God’s universe, to find truth where ever it is, no matter the language or the conventional wisdom or the articles of faith” (Morgan 104). Alhazen’s thinking was forward and progressive for his time. It is a perfect example of the dynamic learning scholars and scientists of the Muslim culture were so enthused to pursue. His belief that the truth of God’s universe had its foundation in science and mathematics was dramatically contrary to the conventional and accepted theological teachings of the religious factions present in the caliphate. It was Alhazen who believed that “in rationalism will…the true mind of God be revealed” (Morgan 98). Alhazen became the man to venture away from the belief of undisputed theological truths.

During the tenth and eleventh centuries, Greek literature was highly influential in Islamic life. The Abbasid Caliphate (from 750) opened its borders to a wide expanse of foreign culture and knowledge. The Islam culture, “adopted Greek concepts and methods of reasoning into the disciplines of theology and law” (Lindberg 67), which proved to be most influential. A result of these adoptions gave way to the rise of philosophy in Islamic culture, directly accompanied by the “reception of Aristotelian canon of rational sciences” (Lindberg 67). The Aristotelian teachings permeated into Islamic culture, influencing also the theological debates within the religious caliphate. Like many other scholars of his time, Alhazen began his search for truth by finding “solace in the thoughts of Aristotle” (Morgan 98). Over the years Alhazen becomes a well-versed man of science as he “expounded the theories…of Aristotle, Galen and Ptolemy and was devoted on philosophy, physics, medicine, optics, astronomy, and mathematics” (Gorini 53). Alhazen’s life works were extensive, as many as two hundred works, many of which will eventually be lost, yet his seven volumes on optics will survive and be widely considered his most important intellectual contribution to a particular field of study (Morgan 103). Alhazen was entranced by the very complexity of light and visual perception. His seven volumes on optics as a complete work was entitled Kitab al-Manazir, translated into The Book of Optics. It is because of the extensive work Alhazen performed that he is considered to this day by many as “one of the most significant figures in the history of optics between antiquity and the 17th century” (Gorini 2003). His Kitab goes on to alter the thinking of many European scholars centuries after he has pioneered the field of study. Alhazen’s scientific advances contributed a vast supply of knowledge “in the history of both medicine and optics and [had] modified the idea that ancients had about light” (Gorini 53). Along with other significant findings, Alhazen disproved the ancient Greek notion of the visual perception of the human eye. Light was Alhazen’s primary interest and he sought to discover the truth whether it was contrary to the Greek theories like those of Ptolemy and Aristotle.

During Alhazen’s time Greek literature and influence was a primary source of knowledge. If it wasn’t for scholarly men, such as Alhazen, future scholars would have relied on this same scholastic form of education: the same ancient text translated from one language to another undisputed. Alhazen took a bold step in the opposite direction of founded knowledge by rejecting all known knowledge. He wished to seek the truth and further understand concepts himself. In his particular investigation into optics Alhazen turned to the early writings of Ptolemy and Aristotle. Until Alhazen delved into the matter of optics, an unsupported and metaphysical based idea of how the eye perceived images was commonly accepted.

The concept of visual perception, accepted by the Greeks, was known as the extramission theory. Many Greek scholars, including Ptolemy, disputed this particular theory. It was, “supposed that the eye sends out rays of light to view the objects.” Aristotle advanced this theory called the “Mediumistic Theory by which the eye receives rays rather than direct them outward. In particular…in the process of human vision the object being looked at somehow altered the medium between the object itself and the viewer’s eye” (Gorini 2003 53). Both theories proved to provide insufficient evidence and support and thus according to Alhazen’s belief the theories had to be rejected.

The Greek scholars made connections between the light and eye sensations but failed to actually explain how it connected to vision perception. Alhazen based his studies on Aristotle’s initial theory, yet instead of basing theory on speculation, he wished to validate his theory upon scientific outcome. In his Kitab Alhazen gives his observations about the nature of light on the human eye:

“We find that when the eye looks into exceedingly bright light, it suffers greatly because of them and is injured; for when an observer looks at the body of the sun, he cannot behold it well, since his eye experiences pain because of its light. Similarly, when he looks into a polished mirror, above which rises the light of the sun, and his eye is in the place to which the light is reflected by the mirror, he will again experience pain because of the reflected light reaching his eye from the mirror, and he will not be able to open his eye to observe that light” (Lindberg 62).

This writing supports Alhazen’s findings, leading to the intromission theory, that the eyes receive rays of light rather than emanating rays in order to visually perceive objects. Through extensive and carefully planned investigation, “Alhazen’s most effective refutation of the extramission theory was his own positive intromission theory” (Lindberg 67). Alhazen provided an answer to the question of vision that was founded in the physical proof of the natural science. Unlike his predecessors he realized more truth was yet to be discovered and, “held that visual perception is not a mere sensation but is primarily an inferential act of discernment and judgment (El-Bizri 344). Alhazen recognized that in order to understand optics, one must make greater connections between light, mathematics, and the anatomical properties of the human eye. The refutation of the extramission theory was one of Alhazen’s multiple contributions to the understanding of optics. Alhazen’s unique methods led to what Lindberg believed to be one of the principle merits of Alhazen’s theory of vision in which he, “successfully integrated the anatomical, physical, and mathematical approaches to sight” (67). No other man before Alhazen utilized many areas of study to define so thoroughly the concept of optics. His extensive scientific work proved to be important because it challenged the works of his Greek predecessors.

In all of his studies Alhazen restricted his knowledge to the physical limitations of the natural sciences. According to Saud, Alhazen recognized that, “in the works of Greeks…Physical knowledge is found to be mixed up with metaphysical speculations” and instead of accepting the knowledge of his Greek predecessors sought to advance it. He did this by substituting “free investigation for authoritarianism” (Saud 10). This relates back to Alhazen’s initial hunger to seek truth despite what knowledge society deemed to be absolute. Alhazen will one day be recognized as the man to, “shrine empirical method over faith and unsubstantial theory” (Morgan 2007). To look at one of his works it would be apparent that Alhazen developed a revolutionary way of investigating theoretical hypotheses of natural science. These developments paved the way for a new dynamic way of scholarly learning.

Alhazen brought Middle-Eastern scholarship out of the educational system of scholastic research clouded with metaphysical speculation, and into a sphere of dynamic experimental science. In order to pursue his own studies Alhazen developed a precise and controlled system of empiricism in which his conclusions were founded upon investigation and experience. Facts were not valid unless verified through personal experience and so “the core lessons of his writings is that science must be based upon empirical methods” (Morgan 103). According to Alhazen, this was the only way scientific knowledge could be validated. The Greeks did have an understanding of empiricism, but were prone to intellectual theorizing rather than gaining knowledge through research. It is important to understand that Alhazen, “did not rely upon authority in scientific conclusions but believed in direct study of Nature” (Saud 1990 7). Alhazen’s ‘against the grain’ method of learning could be viewed as only an attempt to end the quarrels he had once been immersed in as chief minister during theological disputes. These quarrels were only the result of the lack of progressive thinking necessary for a methodical system of dynamic learning. It was Alhazen who advanced this new concept in Muslim culture.

Alhazen acknowledged the lack of method and definition in the way his culture sought knowledge and ultimately succeeded in a remedy. Alhazen “was the pioneer of the modern scientific method…established experiments as the norm of proof in the field” (Gorini 2003 55). Today’s scientific method is directly reflective of Alhazen’s methods as written in his Kitab in which he outlines his empirical method:

We shall commence our investigations of the existing objects through induction and by searching for conditions of the visible objects and by distinguishing between the characteristics of individual objects. And out of the characteristics associated with sight we shall inductively select those which are permanent and immutable and those which are quite clear and not ambiguous during the process of seeing. Then we shall advance in investigation and syllogism gradually and in order, criticize the premises and secure conclusions against errors (Saud 33).

This passage can be divided into a series of steps Alhazen took to investigate a particular study. According to Saud, first was the formulation of a Hypothesis and its Verification, second the Observation of Particulars, third the Classification and Selection of relevant data, and lastly Gradual Induction (34). Alhazen’s method was so exact that if certain observations were not in cohesion with a hypothesis, that particular hypothesis was rejected. Gorini also supports the modern reflection of Alhazen’s method in which it, “consisted of a repeating cycle of observations, hypothesis, experimentation and the need for personal verification” (55). Alhazen can be attributed with some of the initial use of scientific words that are commonly used today as he, “accurately employs the terms experiment, experimentation, examiner, obersver, and find in his study of optics and visual perceptions” (Khaleefa 4). These terms could only be found in the writings of a dynamic scholar, for it is already justified that the Greeks had no ambition like the Islamic people to pursue scholarly research. In his Kitab, he writes:

Let an experimenter take a solid body, make a tiny hole in it, then hold it opposite the sun. He will find that light goes through the hole, moving along a straight line. If he tests the light as it extends through space, he will find it to be perfectly straight. It is therefore clear from all this that the light of the sun only extends along straight lines (Morgan 104).

The basic idea of light travelling in straight lines, so common to us now, was not accepted and had not been proven until Alhazen sought to prove it through his unique empirical method. Alhazen was a prolific writer, whose empirical and rationalized research went to cover multiple facets of the study of optics, and whose influence spread past the borders of the Muslim world, into the beginning of the European Scientific Revolution.

Within a culture, new eras of enlightenment can generally be believed to begin with the adoption and integration of foreign ideas. Just as the Muslim empire received teachings from the Greeks, Persians and other civilizations, so had the Christian European Empire began to receive Muslim influences. Omar supports the correlation of the European scientific revolution with Islamic influence in which, “the revival of scientific activity in Europe in the thirteenth century followed the translation into Latin of many Arabic works on optics, astronomy, mathematics, and medicine” (68). For hundreds of years while Islam enjoyed years of enlightenment and advances in scientific study, Europe sat in the dark ages. It was the works of Islamic scholars like Alhazen, whose Kitab al-Manazir was translated into Latin by the Polish scholar Witelio in 1270 (Gorini 54), which contributed greatly to the new thinking of Europe. The integration of new ideas took time. For many generations the European education system was based solely on the religious teachings of the Christian belief. However, one must also recognize that the scholastic teachings of Europe should not be seen in an entirely negative light. It was the scholastic learning of the European churches that not only preserved knowledge, but also served as the foundation for later dynamic learning. It can be believed then that “the first Christians of Europe cared little for secular knowledge” (Saud 6). It was in the beginning of the twelfth century that medieval Christians began to acquaint themselves with such works as Alhazen’s, practically three centuries after his death. These works however certainly, “dealt a blow to the medieval synthesis of knowledge, and helped the Western scholars to get a true conception of the physical science” (Saud 7). Europeans began to expand their thinking past the Christian foundation, and began to form new understandings. Many scholars through time have wrongly accredited the ideas of Muslim scholars to later European scholars between the thirteenth and seventeenth century. As this Western belief is no longer strongly believed, works and theories very similar and almost identical to those of the great thinker Alhazen are traceable in the works of later Western scientists (Saud 42).

Preserved in his writings Alhazen’s empirical method influenced the works of European methodologists such as Galileo, Roger Bacon (c. 1214-1294), and Johannes Kepler (c. 1571-1630) as well as many others. All of these men studied the works of Alhazen and it is believed by Selah Omar that, “all other Latin works before then [17th c.] repeated Alhazen’s experiments, expatiated his theories, or simply misunderstood much of his work” (69). However, while these men were not the innovators of such a useful scientific method, many European scientists used Alhazen’s influence to better scholarly research and education. It was Alhazen’s mathematical and optic theories that would, “lay the foundation…for Galileo and Copernicus to understand the true relationship of the earth to other heavenly bodies” (Morgan 97). Roger Bacon who was commonly believed by the English to establish empirical method, produced his own writings which “are largely commentaries on [Alhazen’s] writings”, and like Alhazen recognized that problems were still beyond the reach of human capabilities of the time (Khaleefa 3). It wasn’t until Johannes Kepler, a German Mathematician and Astronomer who was perhaps the first European to master Alhazen’s experimental approach to science as well as further the great Muslim’s studies (Omar 68).

Johannes Keper lived during the seventeenth century, the peak of the scientific revolution, where new European knowledge was fully intermixed with the lasting knowledge of its predecessors. Having been influenced by the works of Alhazen, Kepler pursued his own method of rigorous scientific empiricism and, “by insisting upon more rigor and consistency than the medieval perspectivists themselves had been able to achieve, he was able to perfect it” (Lindberg 208). Kepler’s primary achievement was his theory of retinal images. One of Alhazen’s experimental devices he created, the camera obscura, helped define the properties of light and led scholars such as Kepler to the initial concept of the camera. Kepler’s theory for retinal images, “was the natural outcome of comparing the eye to the camera obscura and applying to the eye the knowledge of image-formation acquired in solving the problem of the camera” (Lindberg 205). Kepler provided European education new ideas connected to those once established by Alhazen. At the peak of Europe’s scientific revolution Kepler was able to apply more rigor and make his own advances, “but did so without departing from the basic aims and criteria of visual theory established by Alhazen in the eleventh century” (Lindberg 207).

Through the scientific revolution, it was Alhazen’s new method of epistemology based upon empirical method that “gave sense-perception its proper role in the process of cognition, a role which has…been totally...subordinate to intuition on the Aristotelean theory of knowledge. This theory gave Greek its ‘axiomatic’ approach, so valuable for mathematics, but so stultifying for natural science” (Omar 69-70). From the beginning it was Alhazen who turned away from the idea of self-evident scientific law and turned knowledge rather into validated and probable theories in the realm of natural science.

Not only his theories, but also the knowledge of his work in optics, astronomy, and mathematics became the basis for education throughout history. Alhazen and other Islamic scientists advanced the knowledge of their time. Ancient works such as those of the Greeks were understood through the perception of centuries of Islamic influence and thought. Alhazen was a dedicated scientist whose consistency in precision made him one of the greatest innovators of his time. He came from a culture that held the general belief that knowledge revealed the whole of nature in all honesty. Therefore he refused to be content with the ideas associated with authoritarianism and only accepted the theories of his predecessors after personal verification through inductive methods. The entire lengthy work of Alhazen’s is the ultimate source for the application of his empirical method. His methods of empiricism will go on to be adapted to field of study outside of the ancient areas of knowledge. Western culture would sustain Alhazen’s experimental science through out generations, and it would to be adapted and applied to modern issues. Alhazen’s empirical method would remain to be one of the fundamental concepts in scientific research and education.





Alhazen’s Method of Empiricism and its Contributions to Advancing Science


Page Author: Elizabeth Anne Rathburn

Saturday, 11-Feb-2012 14:19



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