Sunday, June 10, 2007

192)The Science of Optics: Muslim contributions between 800CE and 1350CE.

As a result of the failure to acknowledge adequately the contributions of Muslim scientists to the pantheon of world knowledge between the 7th and 13th centuries, as described in this post: ,

the claim is made that Sir Isaac Newton(d.1727CE) was the founder of modern Optics, as described in this post:

Dr Nader El-Bizri's analysis of developments in the science of Optics shows the substantial and incremental contributions made to this important science by Hunayn ibn Ishaq(d.873CE), al-Kindi(d.ca870CE), ibn al-Haytham(d.ca1039CE), Ibn Sina(d.1037CE), Nasir al-Din Tusi(d.1274CE) and Kamal al-Din al-Farisi(d.1320CE) fully 400-700 years before Isaac Newton.

Ibn al-Haytham's notable contribution to the Science of Optics is also discussed in these posts:

Academic Papers
The Institute of Ismaili Studies


Dr Nader El-Bizri

This is an edited version of an article that was originally published in Medieval Islamic Civilization, An Encyclopaedia, Vol. I, p. 578-579, ed. Josef W. Meri, Routledge (New York-London, 2006).

The science of optics (‘ilm al-manazir) studies the nature and comportment of vision and light, along with phenomena associated with the reflection and refraction of the rays of light. This classical discipline preoccupied numerous mathematicians and physicists in the history of mediaeval science and philosophy in Islam. Its variegated applications were also fundamental in the structuring of several theories in meteorology, astronomy, surveying, and the investigation of the anatomy of the eye and of the psychological aspects of visual perception. The ground-breaking innovative progress of this ancient science was accomplished by Ibn al-Haytham (Alhazen; d. after 1041 CE), and it was further developed by Kamal al-Din al-Farisi (d. 1320 CE).

Key words:
Optika, Ptolemy, vision, Hunayn ibn Ishaq, al-Kindi, Euclid, Ibn al- Haytham, astronomy, Islamic civilization, Avicenna, Nasir al-Din Tusi, intromission, Kitab al-manazir (The Optics), meteorology.

Optics, as a scientific discipline that explores the nature and comportment of vision and light, finds its earliest methodic roots in Euclid’s elementary treatise, the Optika (ca.300 BCE), which eventually was geometrically systematised by Ptolemy (d. ca. 165 CE). According to those polymaths, vision results from the emission of actual light rays from the eye, which take the shape of a cone whose vertex is at the centre of the eye and its base on the surfaces of visible objects. This optical theory reconfirmed Plato’s account in the Timaeus, wherein it was stated that vision is attributed to the soul’s non-consuming fire, which provides the eye with a light that gets emitted into the surrounding air to meet lit objects. This picture was also affirmed in Galen’s (d. ca. 200 CE) anatomy of the eye, whereby he argued that vision occurs due to the eye’s spirit, which passes through the luminous channels of the optical nerve and is radiated onto the external environment as a light ray that travels at an infinite velocity. A similar observation regarding the speed of light was also made by Heron of Alexandria (d. 75 CE) in his work Catoptrics. These mathematical “emission” theories of vision contrasted the physical “intromission” accounts of sight like what is encountered in Aristotle’s De anima (Tract on the Soul) wherein it was ambivalently stated that visual perception results from the introduction of the form of the visible object without its matter into the eye. Although the channels of the transmission of Euclid’s Greek Optika were indeterminate, its Arabic version was preserved under the title Kitab Uqlidus fi ikhtilaf al-manazir. As for Ptolemy’s text, it is known from its Greek source, whereas its Arabic rendition is only recoverable from fragments of Latin translations. One of the earliest engagements with optics in Islam may be traced back to Hunayn ibn Ishaq’s (d. ca. 873 CE) Galenic studies and al-Kindi’s (d. ca. 870 CE) commentaries on Euclid’s Optika; the latter surviving in Latin under the title De aspectibus and were directed by philosophical speculations more than geometric demonstrations.

The most remarkable accomplishment in the science of optics is ultimately achieved in Ibn al-Haytham’s (Alhazen; d. ca.1039 CE) monumental Kitab al-manazir (The Optics: ca.1027 CE), which was translated into Latin as De aspectibus (ca. 1270 CE) and had a focal impact on the tin folding of the perspective tradition in the history of medieval science and Renaissance art. He lived and worked under the patronage of the Fatimid Dynasty, based in Cairo. Gathering the findings of the Ancients, Ibn al-Haytham was able to overcome the main dispute over the nature of vision between the Greek mathematicians and physicists. Rejecting the claim that vision occurs by way of the emission of a light ray from the eye, Ibn al-Haytham systematised the intromission account of vision by demonstrating that seeing results from the introduction of the rays of light into the eye in the shape of a virtual conical model. He moreover supplemented his Optics with a Treatise on Light (Risala fi l-Daw’) that studied the radiating dispersion of light across transparent media in a rectilinear propagation. His optical writings did also incorporate catoptrical explorations of reflection on planar, spherical, cylindrical, parabolic, and conical mirrors. He also integrated the study of lenses and magnification within the science of optics and verified his theoretical hypotheses with controlled tests and experimental installations. The refraction of light also constituted a central subject in his Optics that assisted him in his explorations in astronomy and meteorology.

Although his optical tradition was comprehensively studied and integrated within the European Latin scientific impetus, it, unfortunately, confronted a period of long interruption in transmission within the medieval Islamic civilisation. A parallel engagement in ocular investigations is noted Ibn Sina’s (the noted philosopher and physicians) (Avicenna. d. 1037 CE) critical espousal of the Aristotelian theory of vision which classified optics as a branch of physics rather than mathematics. However, in diverging from Aristotle’s Meteorology, Ibn Sina ultimately advanced an alternate explanation of the phenomenon of the rainbow.

Following his tradition, Nasir al-Din Tusi, the Shia scholar and astronomer, (d.1274 CE) wrote a commentary on Euclid’s Optika that did not show signs of being aware of the optical writings of Ibn al-Haytham. However, the most notable progress in optics which built on Ibn al-Haytham’s results and disseminated them is creditably attributed to Tanqih al-manazir (The Revision of the Optics) by Kamal al-Din al-Farisi (d.1320 CE). Informed by Ibn Sina’s writings, Kamal al-Din revised Ibn al-Haytham’s elucidation of the nature of the rainbow and the halo. Using geometrical constructs to demonstrate how the rainbow results from refraction of light falling on individual raindrops, Kamal al-Din further substantiated his hypothesis by experimentally modelling this process on the passage of light through a spherical vessel filled with water. Following this latest advancement in classical optics, the study of vision in the Muslim world did not progress beyond synoptic summarizations of earlier sources.

Primary Sources

Euclid. The Arabic Version of Euclid’s Optics: Kitab Uqlidus fi Ikhtilaf al-Manazir. Edited and translated by Elaheh Kheirandish. Berlin: Springer Verlag, 1999.
Ibn al-Haytham. Kitab al-manazir. Edited by Abdelhamid I. Sabra. Kuwait: National Council for Culture. Arts and Letters, 1983.
— — The Optics of Ibn al-Haytham, Books I-III, On Direct Vision. Translated by Abdelhamid I. Sabra. London: The Warburg Institute, University of London, 1989.
Ibn Sina. Kitab al-shifa’, Kitab al-nafs. Edited by Fazlur Rahman. Oxford: Oxford University Press, 1960.

Further Reading

Beshara, Saleh O. Ibn al-Haytham’s Optics: A Study of the Origins of Experimental Science. Minneapolis: Bibliotheca Islamica, 1977.
Gul, Russell. “The Emergence of Physiological Optics.” In Encyclopaedia of the History of Arabic Science. Vol. II. Edited by Roshdi Rashed and Regis Morélon. London and New York: Routledge, 1996.
Lindberg, David C. Theories of Vision from al-Kindi to Kepler. Chicago: University of Chicago Press, 1976.
— — “The Western Reception of Arabic Optics.” In Encyclopaedia of the History of Arabic Science. Vol. II. Edited by Roshdi Rashed and Regis Morélon. London and New York: Routledge, 1996.
Rashed, Roshdi. “Geometrical Optics.” In Encyclopaedia of the History of Arabic Science. Vol. II. Edited by Roshdi Rashed and Regis Morélon. London and New York: Routledge, 1996.
— — Optique et mathématiques, recherches sur la pensée scientifique en arabe. Aldershot: Variorum Reprints, 1992.
Sabra, Abdelhamid I. “The Physical and the Mathematical in Ibn al-Haytham’s Theory of Light and Vision.” In The Commemoration Volume of Biruni International Congress in Tehran. Vol. 38. Tehran: High Council of Culture and Arts, 1976.
— — “Sensation and Inference in Alhazen’s Theory of Visual Perception.” In Studies in Perception: Interrelations in the History of Philosophy and Science, Edited by Peter K. Machamer and Robert G. Turnbull. Ohio: Ohio State University Press, 1978.
— — “Optics, Islamic.” In Dictionary of the Middle Ages. Vol. 9. Edited by Joseph R. Strayer. New York: Charles Scribner’s Sons, 1987.


Islam, eminently logical, placing the greatest emphasis on knowledge, purports to understand God's creation:Aga Khan 4(2006)
The God of the Quran is the One whose Ayats(Signs) are the Universe in which we live, move and have our being:Aga Khan 3(1952)
Our interpretation of Islam places enormous value on knowledge. Knowledge is the reflection of faith if it is used properly. Seek out that knowledge and use it properly:Aga Khan 4(2005)