Here’s the latest from the European essayist Fjordman:
My full history of optics and modern science, published in stages at Jihad Watch, Atlas Shrugs and the Gates of Vienna blog, has been published at the GoV. Why do I write about optics? I had heard a number of references to the scholar Ibn al-Haytham or Alhazen, who received compliments even from people who are otherwise very critical of Islamic culture. Because of this I decided to look into his work. I wanted to be able to place him in a historical context, so I read about the history of optics before and after him. It is an undeniable historical fact that photography, the telescope, the microscope and other optical inventions were first made in Europe. Yet if we assume that the Middle East with Mr. Alhazen by the eleventh century AD held a leading position in the optical sciences, why did optics not progress further in that region?
I started out with the intention of writing mainly about Alhazen and Kepler, but the essay eventually grew into a small book of well over 50,000 words. That happens to me a lot. A haiku for me is one thousand words. This essay is part of a larger effort to write a history of science and some other topics as well. The one good thing about having to disprove the historical myths promoted by Muslims and their apologists is that it forces us to look seriously into many aspects of history that we may not normally pay much attention. I have therefore read extensively about the history of mathematics, astronomy, physics, optics and chemistry, among many other things.
I intend to publish my conclusions regarding this, plus a history of beer and chocolate, provided that I can find a publisher for my material. My first book Defeating Eurabia is already available in print. My next book will probably exceed 150,000 words and will include this plus a number of other online essays and a few additional texts which I will reserve for the paper edition. I will soon continue with a history of mathematics and mathematical astronomy in several parts, published at the Gates of Vienna, The Brussels Journal, Atlas Shrugs and Jihad Watch.
I am virtually immune to Political Correctness. The creation of modern science happened in Europe between the seventeenth and the nineteenth centuries; I have so far seen nothing to convince me otherwise. However, I will give credit to people from other cultures when they deserve it. Individuals who do good work should be credited for that, regardless of who they are and where they come from. I agree with Indians who say that their mathematical tradition doesn’t always get the recognition that it deserves. Mathematics is one of the areas where I personally think India has in some periods outperformed China. The Indian numeral system which we use today was NOT invented in the Islamic world, despite what some Muslims like to claim.
I am probably as hostile to Islamic culture as you can possibly get. Nevertheless, while the achievements of “Islamic science” are currently inflated beyond absurdity, there were a few scholars during the medieval period who were at least nominally Muslims and still did good work. Alhazen definitely belongs on that list, perhaps at the very top. I mention him with respect in my history of optics for the simple reason that he has earned my respect. By the eleventh century he probably had the best understanding of human vision achieved by any scholar anywhere in the world until that time. The following quotes by the eminent scholar David C. Lindberg, who is widely recognized as a leading expert on ancient, medieval and early modern optics, refer to his book Theories of vision — From al-Kindi to Kepler.
By far the most important optical work to appear during the Middle Ages was the Book of Optics (Kitab al-Manazir in the original Arabic; De Aspectibus in Latin translation). It was written during the first quarter of the eleventh century by Ibn al-Haytham (965-ca. 1039), who was born in present-day Iraq but spent much of his career in Egypt. He is usually known as Alhazen in Western literature. David C. Lindberg explains:
“Abu ‘Ali al-Hasan ibn al-Haytham (known in medieval Europe as Alhazen or Alhacen) was born in Basra about 965 A.D. The little we know of his life comes from the biobibliographical sketches of Ibn al-Qifti and Ibn Abi Usaibi’a, who report that Alhazen was summoned to Egypt by the Fatimid Khalif, al-Hakim (996-1021), who had heard of Alhazen’s great learning and of his boast that he knew how to regulate the flow of the Nile River. Although his scheme for regulating the Nile proved unworkable, Alhazen remained in Egypt for the rest of his life, patronized by al-Hakim (and, for a time, feigning madness in order to be free of his patron). He died in Cairo in 1039 or shortly after. Alhazen was a prolific writer on all aspects of science and natural philosophy. More than two hundred works are attributed to him by Ibn Abi Usaibi’a, including ninety of which Alhazen himself acknowledged authorship. The latter group, whose authenticity is beyond question, includes commentaries on Euclid’s Elements and Ptolemy’s Almagest, an analysis of the optical works of Euclid and Ptolemy, a resume of the Conics of Apollonius of Perga, and analyses of Aristotle’s Physics, De anima, and Meteorologica.”
Alhazen did work in several scholarly disciplines but is especially remembered for his contributions to optics. He read Hippocrates and Galen on medicine, Plato and Aristotle on philosophy and wrote commentaries on Apollonius, Euclid, Ptolemy, Archimedes’ On the Sphere and Cylinder and other mathematical works. He was probably familiar with al-Kindi’s De aspectibus and Hunain ibn Ishaq’s Ten Treatises, too. Alhazen had the resources to develop a theory of vision which incorporated elements from all of the optical traditions of the past. His treatise contains a substantially correct model of vision: the passive reception of light reflected from other objects, not an active emanation of light rays from the eyes, and he combined mathematical reasoning with some forms of experimental verification. He relied heavily on the Greek scientific tradition, but the synthesis he created was new. Lindberg:
“Alhazen’s essential achievement, it appears to me, was to obliterate the old battle lines. Alhazen was neither Euclidean nor Galenist nor Aristotelian – or else he was all of them. Employing physical and physiological argument, he convincingly demolished the extramission theory; but the intromission theory he erected in its place, while satisfying physical and physiological criteria, also incorporated the entire mathematical framework of Euclid, Ptolemy, and al-Kindi. Alhazen thus drew together the mathematical, medical, and physical traditions and created a single comprehensive theory.”
Curiously, his Book of Optics was not widely used in the Islamic world afterwards. There were a few exceptions such as the Persian natural philosopher Kamal al-Din al-Farisi (1267-ca.1320), but overall, Alhazen’s scientific mindset wasn’t appreciated by his contemporaries. Here is how his writings were received by fellow Muslims, as quoted in Ibn Warraq’s classic Why I Am Not a Muslim:
“A disciple of Maimonides, the Jewish philosopher, relates that he was in Baghdad on business, when the library of a certain philosopher (who died in 1214) was burned there. The preacher, who conducted the execution of the sentence, threw into the flames, with his own hands, an astronomical work of Ibn al-Haitham, after he had pointed to a delineation therein given of the sphere of the earth, as an unhappy symbol of impious Atheism.”
Muslims had access to good ideas, but failed to appreciate their full potential. It was in the West that Alhazen had his greatest influence. The Book of Optics was translated into Latin and had a significant impact on the English scholar Roger Bacon (ca. 1220-1292) and others in the thirteenth century. Bacon was educated at Oxford and lectured on Aristotle at the University of Paris. He wrote about many subjects and was among the first scholars to argue that lenses could be used for the correction of eyesight. His teacher, the English bishop and scholar Robert Grosseteste (ca. 1170-1253), was an early proponent of validating theory through experimentation. Grosseteste played an important role in shaping Oxford University in the first half of the thirteenth century with great intellectual powers and administrative skills.
The great German astronomer Johannes Kepler (1571-1630) was interested in optics before the telescope had been invented and had probably received an introduction to the subject at the university. Kepler was primarily a mathematician and did not personally study the anatomy of the eye, but his description does not contain any major errors. From other scholars he obtained as much anatomical knowledge as he needed to develop his theory of the retinal image. Alhazen’s contributions influenced most important works on optics written in Europe up to and including Kepler, but it was nevertheless Kepler, not Alhazen, who created the first recognizably modern theory of human vision. Lindberg:
“He has painstakingly demonstrated that all the radiation from a point in the visual field entering the eye must be returned to a point of focus on the retina. If all the radiation entering the eye must be taken into account (and who could gainsay that proposition after reflecting on Kepler’s argument?), and if the requirement of a one-to-one correspondence between the point sources of rays in the visual field and points in the eye stimulated by those rays is accepted, then Kepler’s theory appears to be established beyond serious dispute. An inverted picture is painted on the retina, as on the back of the camera obscura, reproducing all the visual features of the scene before the eye. The fact that Kepler’s geometrical scheme perfectly complemented Platter’s teaching about the sensitivity of the retina surely helped to confirm this conclusion. It is perhaps significant that Kepler employed the term pictura in discussing the inverted retinal image, for this is the first genuine instance in the history of visual theory of a real optical image within the eye — a picture, having an existence independent of the observer, formed by the focusing of all available rays on a surface.”
Kepler compared the eye to a camera obscura, but only once in his treatise. The most difficult challenge was the fact that the picture on the retina is upside down and reversed from right to left. This inverted picture caused Kepler considerable problems. He lacked the means to cope with this issue but argued that “geometrical laws leave no choice in the matter” and excluded the problem from optics, separating the optical from the nonoptical aspects of vision, which was the sensible thing to do. Optics ceases with the formation of the picture on the retina. What happens after that is for somebody else to find out. The image gets turned “right” by the brain, but the functions of the brain were not understood by any culture at that time.
The history of the camera is older than the history of photography. The basic principles behind the pinhole camera, a precursor to the camera obscura (Latin: dark chamber), were understood by Aristotle and the ancients Greeks in the fourth century BC as well as the Chinese engineer and thinker Mo Ti or Mozi in the fifth century BC. The school of thought that he founded, Mohism, flourished during the Warring States era (479-221 BC) prior to the unification of Imperial China. During this period it provided a crucial stimulus for Confucian thinkers Mencius and Xunzi, for Daoists and for Legalists, adherents of the militaristic-totalitarian ideology which enabled the Qin state to unify China under its First Emperor. However, Mozi’s optical ideas were not widely followed in China later.
One exception was the government official and polymath Shen Kuo or Shen Kua (AD 1031-1095). In his major work Mengxi bitan or Dream Pool Essays of 1088, Shen Kuo experimented with the camera obscura as the Mohists had done. He had promising insights into many other subjects, too, ranging from meteorology and geology to fossils. However, these insights usually lacked clear-cut organization and were not developed into coherent scientific theories. Although the Chinese did on occasion perform various experiments with mirrors and other optical tools, progress in optics stagnated in China after initial advances. The clearest medieval description of the camera obscura was made by Alhazen (Ibn al-Haytham) in the Middle East. Toby E. Huff explains in The Rise of Early Modern Science, second edition:
“In optics, which in early science probably played something like the role of physics in modern science, the Chinese, in Needham’s words, “˜never equalled the highest level attained by the Islamic students of light such as Ibn al-Haytham.” Among other reasons, this was a reflection of the fact that the Chinese were “˜greatly hampered by the lack of the Greek deductive geometry” that the Arabs had inherited. Finally, though we think of physics as the fundamental natural science, Joseph Needham concluded that there was very little systematic physical thought among the Chinese. While one can find Chinese physical thought, “˜one can hardly speak of a developed science of physics,” and it lacked powerful systematic thinkers, who could correspond to the so-called precursors of Galileo, represented in the West by such names as Philoponus, Buridan, Bradwardine, and Nicole d”Oresme.”
Photography was born when the camera was combined with chemical advances necessary to permanently capture images. This was first done successfully by the Frenchman Joseph NicÃ©phore NiÃ©pce (1765-1833) in the 1820s.
David C. Lindberg argues that Alhazen’s Book of Optics must have been translated during the late twelfth or early thirteenth century. Indirect evidence indicates Spain as the point of translation, and the high quality of the translation points to the great Italian (Lombard) translator Gerard of Cremona (ca. 1114-1187) or somebody from his school, although we do not know this with certainty. Many of the works initially translated from Arabic by Gerard and his associates, among them Ptolemy’s great astronomical work the Almagest, were later translated directly from Greek into Latin from Byzantine manuscripts. Obviously, Alhazen’s work had to be translated from Arabic since it was written in that language in the first place.
Kepler’s earliest work was based on the naked-eye observations of the astronomer Tycho Brahe (1546-1601) from Denmark, the last and the greatest of the pre-telescopic observers. Kepler was the founder of modern optics; the first to describe upright and inverted images and the concept of magnification. He made the first thorough theoretical explanation of how eyeglasses work. After he became familiar with the telescope used by Galileo Galilei in late 1609 and early 1610, he extended this explanation to the new invention as well.
Although Kepler’s theory of the retinal image, not Alhazen’s work, is identified as the birth of modern optical theory, Lindberg argues that he was the culminating figure of centuries of scholarship. Alhazen inspired many European optical scholars during the late medieval and early modern period, up to and including Kepler:
“That his theory of vision had revolutionary implications, which would be unfolded in the course of the seventeenth century, must not be allowed to obscure the fact that Kepler himself remained firmly within the medieval framework. The theory of the retinal image constituted an alteration in the superstructure of visual theory; at bottom, it remained solidly upon a medieval foundation. Kepler attacked the problem of vision with greater skill than had theretofore been applied to it, but he did so without departing from the basic aims and criteria of visual theory established by Alhazen in the eleventh century. Thus neither extreme of the continuity-discontinuity spectrum will suffice to describe Kepler’s achievement: his theory of vision was not anticipated by medieval scholars; nor did he formulate his theory out of reaction to, or as a repudiation of, the medieval achievement. Rather, Kepler presented a new solution (but not a new kind of solution) to a medieval problem, defined some six hundred years earlier by Alhazen. By taking the medieval tradition seriously, by accepting its most basic assumptions but insisting upon more rigor and consistency than the medieval perspectivists themselves had been able to achieve, he was able to perfect it.”