Alhazen

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Ibn al-Haytham
(Alhazen)
Ibn al-Haytham.png
Born (965-07-01)July 1, 965 CE[1] (354 AH)[2]
Basra, Buyid Emirate
Died March 6, 1040(1040-03-06) (aged 74)[1] (430 AH)[3]
Cairo, Egypt, Fatimid Caliphate
Residence
Fields
Known for

Abū ʿAlī al-Ḥasan ibn al-Ḥasan ibn al-Haytham (Arabic: أبو علي، الحسن بن الحسن بن الهيثم‎), frequently referred to as Ibn al-Haytham (Arabic: ابن الهيثم, Latinized as Alhazen[Notes 1] or Alhacen; c. 965 – c. 1040) was an Arab[8] scientist, polymath, mathematician, astronomer and philosopher who made significant contributions to the principles of optics, astronomy, mathematics, meteorology,[9] visual perception and the scientific method.

He has been described as the father of modern optics, ophthalmology,[10] experimental physics and scientific methodology[11][12][13] and the first theoretical physicist[14] In medieval Europe, he was nicknamed Ptolemaeus Secundus ("Ptolemy the Second")[15] or simply called "The Physicist".[16] He is also sometimes called al-Basri (Arabic: البصري) after Basra, his birthplace.[17]

According to one version of his biography,[18] al-Haytham, confident about the practical application of his mathematical knowledge, assumed he could regulate the floods of the Nile. Having been ordered to do so by Al-Hakim bi-Amr Allah, the sixth ruler of the Fatimid caliphate, he quickly realised its impossibility. Fearing for his life, he feigned madness[1][19] and was placed under house arrest. Once Al-Hakim had died, he was able to prove that he was not mad and for the rest of his life made money copying texts while writing mathematical works and teaching.[20]

Overview[edit]

Biography[edit]

Alhazen, the polymath.

Born c. 965 in Basra, which was then part of the Buyid emirate,[1] to an Arab family,[21][22] he lived mainly in Cairo, Egypt, dying there at age 74.[15] During the Islamic Golden Age, Basra was a "key beginning of learning",[23] and he was educated there and in Baghdad, the capital of the Abbasid Caliphate, and the focus of the "high point of Islamic civilization".[23] During his time in Basra, he trained for government work and became Minister for the area.[17]

One account of his career has him called to Egypt by Al-Hakim bi-Amr Allah, ruler of the Fatimid Caliphate, to regulate the flooding of the Nile, a task requiring an early attempt at building a dam at the present site of the Aswan Dam.[24] After deciding the scheme was impractical and fearing the caliph's anger, he feigned madness. He was kept under house arrest from 1011 until al-Hakim's death in 1021.[25] During this time, he wrote his influential Book of Optics. After his house arrest ended, he wrote scores of other treatises on physics, astronomy and mathematics. He later traveled to Islamic Spain. During this period, he had ample time for his scientific pursuits, which included optics, mathematics, physics, medicine, and practical experiments.

Some biographers have claimed that Alhazen fled to Syria, ventured into Baghdad later in his life, or was in Basra when he pretended to be insane. In any case, he was in Egypt by 1038.[17] Accounts state that during his time in Cairo he lived near and studied at the Al-Azhar Mosque.[26]

Among his students were Sorkhab (Sohrab), a Persian from Iran's Semnan who was his student for over 3 years, and Abu al-Wafa Mubashir ibn Fatek, an Egyptian scientist who learned mathematics from Alhazan.[27]

Legacy[edit]

Front page of a Latin edition of Alhazen's Thesaurus opticus, showing how Archimedes set on fire the Roman ships before Syracuse with the help of parabolic mirrors.

Alhazen made significant improvements in optics, physical science, and the scientific method. Alhazen's work on optics is credited with contributing a new emphasis on experiment. Alhazen is considered by British-Iraqi physicist, Jim Al-Khalili, to be the "first true scientist" based on Alhazen's pioneering work on the scientific method.[14]

His main work, Kitab al-Manazir (Book of Optics) had little direct influence in the Islamic Middle East, being known mainly through a thirteenth-century commentary by Kamāl al-Dīn al-Fārisī, the Tanqīḥ al-Manāẓir li-dhawī l-abṣār wa l-baṣā'ir.[28] In Islamic Spain it was used by the eleventh-century mathematician, al-Mu'taman ibn Hūd, and a Latin translation was produced in the thirteenth century.[29][30] Through this translation, Alhazen exerted a great influence on Western science: for example, on the work of Roger Bacon,[31] Robert Grosseteste,[32] Witelo, Leonardo Di Vinci,[33] Christian Huygens,[34] and Johannes Kepler.[35] His research in catoptrics (the study of optical systems using mirrors) centred on spherical and parabolic mirrors and spherical aberration. He made the observation that the ratio between the angle of incidence and refraction does not remain constant, and investigated the magnifying power of a lens. His work on catoptrics also contains the problem known as "Alhazen's problem".[36] Meanwhile in the Islamic world, Alhazen's work influenced Averroes' writings on optics,[37] and his legacy was further advanced through the 'reforming' of his Optics by Persian scientist Kamal al-Din al-Farisi (died ca. 1320) in the latter's Kitab Tanqih al-Manazir (The Revision of [Ibn al-Haytham's] Optics).[38] Alhazen wrote as many as 200 books, although only 55 have survived, and many of those have not yet been translated from Arabic.[citation needed] Some of his treatises on optics survived only through Latin translation. During the Middle Ages his books on cosmology were translated into Latin, Hebrew and other languages. The crater Alhazen on the Moon is named in his honour,[39] as was the asteroid 59239 Alhazen.[40] In honour of Alhazen, the Aga Khan University (Pakistan) named its Ophthalmology endowed chair as "The Ibn-e-Haitham Associate Professor and Chief of Ophthalmology".[41] Alhazen, by the name Ibn al-Haytham, is featured on the obverse of the Iraqi 10,000-dinar banknote issued in 2003,[42] and on 10-dinar notes from 1982. A research facility that UN weapons inspectors suspected of conducting chemical and biological weapons research in Saddam Hussein's Iraq was also named after him.[42][43]

Book of Optics[edit]

Alhazen's most famous work is his seven-volume treatise on optics Kitab al-Manazir (Book of Optics), written from 1011 to 1021.

Optics was translated into Latin by an unknown scholar at the end of the 12th century or the beginning of the 13th century.[44] It was printed by Friedrich Risner in 1572, with the title Opticae thesaurus: Alhazeni Arabis libri septem, nuncprimum editi; Eiusdem liber De Crepusculis et nubium ascensionibus (English : Optics treasure: Arab Alhazeni seven books, published for the first time: The book of the Twilight of the clouds and ascensions).[45] Risner is also the author of the name variant "Alhazen"; before Risner he was known in the west as Alhacen, which is the correct transcription of the Arabic name.[46] This work enjoyed a great reputation during the Middle Ages. Works by Alhazen on geometric subjects were discovered in the Bibliothèque nationale in Paris in 1834 by E. A. Sedillot. Other manuscripts are preserved in the Bodleian Library at Oxford and in the library of Leiden.

Theory of vision[edit]

Alhazen on Iraqi 10 Dinars

Two major theories on vision prevailed in classical antiquity. The first theory, the emission theory, was supported by such thinkers as Euclid and Ptolemy, who believed that sight worked by the eye emitting rays of light. The second theory, the intromission theory supported by Aristotle and his followers, had physical forms entering the eye from an object. Previous Islamic writers (such as al-Kindi) had argued essentially on Euclidean, Galenist, or Aristotelian lines; Alhazen's achievement was to come up with a theory which successfully combined parts of the mathematical ray arguments of Euclid, the medical tradition of Galen, and the intromission theories of Aristotle. Alhazen's intromission theory followed al-Kindi (and broke with Aristotle) in asserting that "from each point of every colored body, illuminated by any light, issue light and color along every straight line that can be drawn from that point".[47] This however left him with the problem of explaining how a coherent image was formed from many independent sources of radiation; in particular, every point of an object would send rays to every point on the eye. What Alhazen needed was for each point on an object to correspond to one point only on the eye.[47] He attempted to resolve this by asserting that only perpendicular rays from the object would be perceived by the eye; for any one point on the eye, only the ray which reached it directly, without being refracted by any other part of the eye, would be perceived. He argued using a physical analogy that perpendicular rays were stronger than oblique rays; in the same way that a ball thrown directly at a board might break the board, whereas a ball thrown obliquely at the board would glance off, perpendicular rays were stronger than refracted rays, and it was only perpendicular rays which were perceived by the eye. As there was only one perpendicular ray that would enter the eye at any one point, and all these rays would converge on the centre of the eye in a cone, this allowed him to resolve the problem of each point on an object sending many rays to the eye; if only the perpendicular ray mattered, then he had a one-to-one correspondence and the confusion could be resolved.[48] He later asserted (in book seven of the Optics) that other rays would be refracted through the eye and perceived as if perpendicular.[49]

His arguments regarding perpendicular rays do not clearly explain why only perpendicular rays were perceived; why would the weaker oblique rays not be perceived more weakly?[50] His later argument that refracted rays would be perceived as if perpendicular does not seem persuasive.[51] However, despite its weaknesses, no other theory of the time was so comprehensive, and it was enormously influential, particularly in Western Europe: "Directly or indirectly, his De Aspectibus inspired much of the activity in optics which occurred between the 13th and 17th centuries." [52] Kepler's later theory of the retinal image (which resolved the problem of the correspondence of points on an object and points in the eye) built directly on the conceptual framework of Alhazen.[52]

Alhazen showed through experiment that light travels in straight lines, and carried out various experiments with lenses, mirrors, refraction, and reflection.[36] He was the first to consider separately the vertical and horizontal components of reflected and refracted light rays, which was an important step in understanding optics geometrically.[53]

The camera obscura was known to the Chinese, and Aristotle had discussed the principle behind it in his Problems, however it is Alhazen's work which contains the first clear description[54] and early analysis[55] of the device.

Alhazen studied the process of sight, the structure of the eye, image formation in the eye, and the visual system. Ian P. Howard argued in a 1996 Perception article that Alhazen should be credited with many discoveries and theories which were previously attributed to Western Europeans writing centuries later. For example, he described what became in the 19th century Hering's law of equal innervation; he had a description of vertical horopters which predates Aguilonius by 600 years and is actually closer to the modern definition than Aguilonius's; and his work on binocular disparity was repeated by Panum in 1858.[56] Craig Aaen-Stockdale, while agreeing that Alhazen should be credited with many advances, has expressed some caution, especially when considering Alhazen in isolation from Ptolemy, who Alhazen was extremely familiar with. Alhazen corrected a significant error of Ptolemy regarding binocular vision, but otherwise his account is very similar; Ptolemy also attempted to explain what is now called Hering's law.[57] In general, Alhazen built on and expanded the optics of Ptolemy.[58][59] In a more detailed account of Ibn al-Haytham's contribution to the study of binocular vision based on Lejeune[60] and Sabra,[18] Raynaud[61] showed that the concepts of correspondence, homonymous and crossed diplopia were in place in Ibn al-Haytham's optics. But contrary to Howard, he explained why Ibn al-Haytham did not give the circular figure of the horopter and why, by reasoning experimentally, he was in fact closer to the discovery of Panum's fusional area than that of the Vieth-Müller circle. In this regard, Ibn al-Haytham's theory of binocular vision faced two main limits: the lack of recognition of the role of the retina, and obviously the lack of an experimental investigation of ocular tracts.

Alhazen's most original contribution was that after describing how he thought the eye was anatomically constructed, he went on to consider how this anatomy would behave functionally as an optical system.[62] His understanding of pinhole projection from his experiments appears to have influenced his consideration of image inversion in the eye,[63] which he sought to avoid.[64] He maintained that the rays that fell perpendicularly on the lens (or glacial humor as he called it) were further refracted outward as they left the glacial humor and the resulting image thus passed upright into the optic nerve at the back of the eye.[65] He followed Galen in believing that the lens was the receptive organ of sight, although some of his work hints that he thought the retina was also involved.[66]

Scientific method[edit]

Frontispiece of book showing two persons in robes, one holding a geometrical diagram, the other holding a telescope.
Hevelius's Selenographia, showing Alhasen [sic] representing reason, and Galileo representing the senses.
The duty of the man who investigates the writings of scientists, if learning the truth is his goal, is to make himself an enemy of all that he reads, and,.. attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency.

—Alhazen, [18]

An aspect associated with Alhazen's optical research is related to systemic and methodological reliance on experimentation (i'tibar)(Arabic: إختبار) and controlled testing in his scientific inquiries. Moreover, his experimental directives rested on combining classical physics (ilm tabi'i) with mathematics (ta'alim; geometry in particular). This mathematical-physical approach to experimental science supported most of his propositions in Kitab al-Manazir (The Optics; De aspectibus or Perspectivae) and grounded his theories of vision, light and colour, as well as his research in catoptrics and dioptrics (the study of the refraction of light).[38] Bradley Steffens in his book Ibn Al-Haytham: First Scientist has argued that Alhazen's approach to testing and experimentation made an important contribution to the scientific method. According to Matthias Schramm, Alhazen:

was the first to make a systematic use of the method of varying the experimental conditions in a constant and uniform manner, in an experiment showing that the intensity of the light-spot formed by the projection of the moonlight through two small apertures onto a screen diminishes constantly as one of the apertures is gradually blocked up.[67]

G. J. Toomer expressed some skepticism regarding Schramm's view, arguing that caution is needed to avoid reading anachronistically particular passages in Alhazen's very large body of work, and while acknowledging Alhazen's importance in developing experimental techniques, argued that he should not be considered in isolation from other Islamic and ancient thinkers.[68]

Alhazen's problem[edit]

His work on catoptrics in Book V of the Book of Optics contains a discussion of what is now known as Alhazen's problem, first formulated by Ptolemy in 150 AD. It comprises drawing lines from two points in the plane of a circle meeting at a point on the circumference and making equal angles with the normal at that point. This is equivalent to finding the point on the edge of a circular billiard table at which a cue ball at a given point must be aimed in order to carom off the edge of the table and hit another ball at a second given point. Thus, its main application in optics is to solve the problem, "Given a light source and a spherical mirror, find the point on the mirror where the light will be reflected to the eye of an observer." This leads to an equation of the fourth degree.[17][69] This eventually led Alhazen to derive a formula for the sum of fourth powers, where previously only the formulas for the sums of squares and cubes had been stated. His method can be readily generalized to find the formula for the sum of any integral powers, although he did not himself do this (perhaps because he only needed the fourth power to calculate the volume of the paraboloid he was interested in). He used his result on sums of integral powers to perform what would now be called an integration, where the formulas for the sums of integral squares and fourth powers allowed him to calculate the volume of a paraboloid.[70] Alhazen eventually solved the problem using conic sections and a geometric proof. His solution was extremely long and complicated and may not have been understood by mathematicians reading him in Latin translation. Later mathematicians used Descartes' analytical methods to analyse the problem,[71] with a new solution being found in 1997 by the Oxford mathematician Peter M. Neumann.[72] Recently, Mitsubishi Electric Research Laboratories (MERL) researchers Amit Agrawal, Yuichi Taguchi and Srikumar Ramalingam solved the extension of Alhazen's problem to general rotationally symmetric quadric mirrors including hyperbolic, parabolic and elliptical mirrors.[73] They showed that the mirror reflection point can be computed by solving an eighth degree equation in the most general case. If the camera (eye) is placed on the axis of the mirror, the degree of the equation reduces to six.[74] Alhazen's problem can also be extended to multiple refractions from a spherical ball. Given a light source and a spherical ball of certain refractive index, the closest point on the spherical ball where the light is refracted to the eye of the observer can be obtained by solving a tenth degree equation.[74]

Other contributions[edit]

The Book of Optics describes several experimental observations that Alhazen made and how he used his results to explain certain optical phenomena using mechanical analogies. He conducted experiments with projectiles, and a description of his conclusions is: "it was only the impact of perpendicular projectiles on surfaces which was forceful enough to enable them to penetrate whereas the oblique ones were deflected. For example, to explain refraction from a rare to a dense medium, he used the mechanical analogy of an iron ball thrown at a thin slate covering a wide hole in a metal sheet. A perpendicular throw would break the slate and pass through, whereas an oblique one with equal force and from an equal distance would not."[75] He also used this result to explain how intense, direct light hurts the eye, using a mechanical analogy: "Alhazen associated 'strong' lights with perpendicular rays and 'weak' lights with oblique ones. The obvious answer to the problem of multiple rays and the eye was in the choice of the perpendicular ray since there could only be one such ray from each point on the surface of the object which could penetrate the eye."[75]

Sudanese psychologist Omar Khaleefa has argued that Alhazen should be considered be the "founder of experimental psychology", for his pioneering work on the psychology of visual perception and optical illusions.[76] Khaleefa has also argued that Alhazen should also be considered the "founder of psychophysics", a sub-discipline and precursor to modern psychology.[76] Although Alhazen made many subjective reports regarding vision, there is no evidence that he used quantitative psychophysical techniques and the claim has been rebuffed.[57]

Alhazen offered an explanation of the Moon illusion, an illusion that played an important role in the scientific tradition of medieval Europe.[77] Many authors repeated explanations that attempted to solve the problem of the Moon appearing larger near the horizon than it does when higher up in the sky, a debate that is still unresolved. Alhazen argued against Ptolemy's refraction theory, and defined the problem in terms of perceived, rather than real, enlargement. He said that judging the distance of an object depends on there being an uninterrupted sequence of intervening bodies between the object and the observer. When the Moon is high in the sky there are no intervening objects, so the Moon appears close. The perceived size of an object of constant angular size varies with its perceived distance. Therefore, the Moon appears closer and smaller high in the sky, and further and larger on the horizon. Through works by Roger Bacon, John Pecham and Witelo based on Alhazen's explanation, the Moon illusion gradually came to be accepted as a psychological phenomenon, with the refraction theory being rejected in the 17th century.[78] Although Alhazen is often credited with the perceived distance explanation, he was not the first author to offer it. Cleomedes (c. 2nd century) gave this account (in addition to refraction), and he credited it to Posidonius (c. 135-50 BC).[79] Ptolemy may also have offered this explanation in his Optics, but the text is obscure.[80] Alhazen's writings were more widely available in the Middle Ages than those of these earlier authors, and that probably explains why Alhazen received the credit.

Other works on physics[edit]

Optical treatises[edit]

Besides the Book of Optics, Alhazen wrote several other treatises on the same subject, including his Risala fi l-Daw’ (Treatise on Light). He investigated the properties of luminance, the rainbow, eclipses, twilight, and moonlight. Experiments with mirrors and magnifying lenses provided the foundation for his theories on catoptrics.[81]

In his treatise Mizan al-Hikmah (Balance of Wisdom), Alhazen discussed the density of the atmosphere and related it to altitude. He also studied atmospheric refraction.[36]

Celestial physics[edit]

Alhazen discussed the physics of the celestial region in his Epitome of Astronomy, arguing that Ptolemaic models needed to be understood in terms of physical objects rather than abstract hypotheses; in other words that it should be possible to create physical models where (for example) none of the celestial bodies would collide with each other. The suggestion of mechanical models for the Earth centred Ptolemaic model "greatly contributed to the eventual triumph of the Ptolemaic system among the Christians of the West". Alhazen's determination to root astronomy in the realm of physical objects was important however, because it meant astronomical hypotheses "were accountable to the laws of physics", and could be criticised and improved upon in those terms.[82]

In Mizan al-Hikmah (Balance of Wisdom), Alhazen discussed the theories of attraction between masses.[36] He also wrote Maqala fi daw al-qamar (On the Light of the Moon).

Mechanics[edit]

In his work, Alhazen discussed theories on the motion of a body.[81] In his Treatise on Place, Alhazen disagreed with Aristotle's view that nature abhors a void, and he used geometry in an attempt to demonstrate that place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body.[83]

Astronomical works[edit]

On the Configuration of the World[edit]

In his On the Configuration of the World Alhazen presented a detailed description of the physical structure of the earth:

The earth as a whole is a round sphere whose center is the center of the world. It is stationary in its [the world's] middle, fixed in it and not moving in any direction nor moving with any of the varieties of motion, but always at rest.[84]

The book is a non-technical explanation of Ptolemy's Almagest, which was eventually translated into Hebrew and Latin in the 13th and 14th centuries and subsequently had an influence on astronomers such as Georg von Peuerbach[1] during the European Middle Ages and Renaissance.[85][86]

Doubts Concerning Ptolemy[edit]

In his Al-Shukūk ‛alā Batlamyūs, variously translated as Doubts Concerning Ptolemy or Aporias against Ptolemy, published at some time between 1025 and 1028, Alhazen criticized Ptolemy's Almagest, Planetary Hypotheses, and Optics, pointing out various contradictions he found in these works, particularly in astronomy. Ptolemy's Almagest concerned mathematical theories regarding the motion of the planets, whereas the Hypotheses concerned what Ptolemy thought was the actual configuration of the planets. Ptolemy himself acknowledged that his theories and configurations did not always agree with each other, arguing that this was not a problem provided it did not result in noticeable error, but Alhazen was particularly scathing in his criticism of the inherent contradictions in Ptolemy's works.[87] He considered that some of the mathematical devices Ptolemy introduced into astronomy, especially the equant, failed to satisfy the physical requirement of uniform circular motion, and noted the absurdity of relating actual physical motions to imaginary mathematical points, lines and circles:[88]

Ptolemy assumed an arrangement (hay'a) that cannot exist, and the fact that this arrangement produces in his imagination the motions that belong to the planets does not free him from the error he committed in his assumed arrangement, for the existing motions of the planets cannot be the result of an arrangement that is impossible to exist... [F]or a man to imagine a circle in the heavens, and to imagine the planet moving in it does not bring about the planet's motion.[89][90]

Having pointed out the problems, Alhazen appears to have intended to resolve the contradictions he pointed out in Ptolemy in a later work. Alhazen's belief was that there was a "true configuration" of the planets which Ptolemy had failed to grasp; his intention was to complete and repair Ptolemy's system, not to replace it completely.[87]

In the Doubts Concerning Ptolemy Alhazen set out his views on the difficulty of attaining scientific knowledge and the need to question existing authorities and theories:

Truth is sought for itself [but] the truths, [he warns] are immersed in uncertainties [and the scientific authorities (such as Ptolemy, whom he greatly respected) are] not immune from error...[18]

He held that the criticism of existing theories—which dominated this book—holds a special place in the growth of scientific knowledge.

Model of the Motions of Each of the Seven Planets[edit]

Alhazen's The Model of the Motions of Each of the Seven Planets was written c. 1038. Only one damaged manuscript has been found, with only the introduction and the first section, on the theory of planetary motion, surviving. (There was also a second section on astronomical calculation, and a third section, on astronomical instruments.) Following on from his Doubts on Ptolemy, Alhazen described a new, geometry based planetary model, describing the motions of the planets in terms of spherical geometry, infinitesimal geometry and trigonometry. He kept a geocentric universe and assumed that celestial motions are uniformly circular, which required the inclusion of epicycles to explain observed motion, but he managed to eliminate Ptolemy's equant. In general, his model made no attempt to provide a causal explanation of the motions, but concentrated on providing a complete, geometric description which could be used to explain observed motions, without the contradictions inherent in Ptolemy's model.[91]

Other astronomical works[edit]

Alhazen wrote a total of twenty-five astronomical works, some concerning technical issues such as Exact Determination of the Meridian, a second group concerning accurate astronomical observation, a third group concerning various astronomical problems and questions such as the location of the Milky Way; Alhazen argued for a distant location, based on the fact that it does not move in relation to the fixed stars.[92] The fourth group consists of ten works on astronomical theory, including the Doubts and Model of the Motions discussed above.[93]

Mathematical works[edit]

In mathematics, Alhazen built on the mathematical works of Euclid and Thabit ibn Qurra and worked on "the beginnings of the link between algebra and geometry."[94]

Geometry[edit]

The lunes of Alhazen. The two blue lunes together have the same area as the green right triangle.

In geometry, Alhazen developed analytical geometry and the link between algebra and geometry.[94] He developed a formula for adding the first 100 natural numbers, using a geometric proof to prove the formula.[95]

Alhazen explored the Euclidean parallel postulate, the fifth postulate in Euclid's Elements, using a proof by contradiction,[96] and in effect introducing the concept of motion into geometry.[97] He formulated the Lambert quadrilateral, which Boris Abramovich Rozenfeld names the "Ibn al-Haytham–Lambert quadrilateral".[98] His theorems on quadrilaterals, including the Lambert quadrilateral, were the first theorems on elliptical geometry and hyperbolic geometry. These theorems, along with his alternative postulates, such as Playfair's axiom, can be seen as marking the beginning of non-Euclidean geometry. His work had a considerable influence on its development among the later Persian geometers Omar Khayyám and Nasīr al-Dīn al-Tūsī, and the European geometers Witelo, Gersonides, and Alfonso.[99]

In elementary geometry, Alhazen attempted to solve the problem of squaring the circle using the area of lunes (crescent shapes), but later gave up on the impossible task.[17] The two lunes formed from a right triangle by erecting a semicircle on each of the triangle's sides, inward for the hypotenuse and outward for the other two sides, are known as the lunes of Alhazen; they have the same total area as the triangle itself.[100]

Number theory[edit]

His contributions to number theory include his work on perfect numbers. In his Analysis and Synthesis, Alhazen may have been the first to state that every even perfect number is of the form 2n−1(2n − 1) where 2n − 1 is prime, but he was not able to prove this result successfully (Euler later proved it in the 18th century).[17]

Alhazen solved problems involving congruences using what is now called Wilson's theorem. In his Opuscula, Alhazen considers the solution of a system of congruences, and gives two general methods of solution. His first method, the canonical method, involved Wilson's theorem, while his second method involved a version of the Chinese remainder theorem.[17]

Other works[edit]

Influence of Melodies on the Souls of Animals[edit]

Alhazen also wrote a Treatise on the Influence of Melodies on the Souls of Animals, although no copies have survived. It appears to have been concerned with the question of whether animals could react to music, for example whether a camel would increase or decrease its pace.

Engineering[edit]

In engineering, one account of his career as a civil engineer has him summoned to Egypt by the Fatimid Caliph, Al-Hakim bi-Amr Allah, to regulate the flooding of the Nile River. He carried out a detailed scientific study of the annual inundation of the Nile River, and he drew plans for building a dam, at the site of the modern-day Aswan Dam. His field work, however, later made him aware of the impracticality of this scheme, and he soon feigned madness so he could avoid punishment from the Caliph.[101]

Philosophy[edit]

In his Treatise on Place, Alhazen disagreed with Aristotle's view that nature abhors a void, and he used geometry in an attempt to demonstrate that place (al-makan) is the imagined three-dimensional void between the inner surfaces of a containing body.[83] Abd-el-latif, a supporter of Aristotle's philosophical view of place, later criticized the work in Fi al-Radd ‘ala Ibn al-Haytham fi al-makan (A refutation of Ibn al-Haytham’s place) for its geometrization of place.[83]

Alhazen also discussed space perception and its epistemological implications in his Book of Optics. In "tying the visual perception of space to prior bodily experience, Alhacen unequivocally rejected the intuitiveness of spatial perception and, therefore, the autonomy of vision. Without tangible notions of distance and size for correlation, sight can tell us next to nothing about such things."[102]

Theology[edit]

Alhazen was a devout Muslim, though it is uncertain which branch of Islam he followed. He may have been either a follower of the Ash'ari school of Sunni Islamic theology according to Ziauddin Sardar[103] and Lawrence Bettany[104] (and opposed to the views of the Mu'tazili school),[104] a follower of the Mu'tazili school of Islamic theology according to Peter Edward Hodgson,[105] or a follower of Shia Islam possibly according to A. I. Sabra.[106]

Alhazen wrote a work on Islamic theology, in which he discussed prophethood and developed a system of philosophical criteria to discern its false claimants in his time.[107] He also wrote a treatise entitled Finding the Direction of Qibla by Calculation, in which he discussed finding the Qibla, where Salat prayers are directed towards, mathematically.[108]

He wrote in his Doubts Concerning Ptolemy:

Truth is sought for its own sake ... Finding the truth is difficult, and the road to it is rough. For the truths are plunged in obscurity. ... God, however, has not preserved the scientist from error and has not safeguarded science from shortcomings and faults. If this had been the case, scientists would not have disagreed upon any point of science...[109]

In The Winding Motion, Alhazen further wrote:

From the statements made by the noble Shaykh, it is clear that he believes in Ptolemy's words in everything he says, without relying on a demonstration or calling on a proof, but by pure imitation (taqlid); that is how experts in the prophetic tradition have faith in Prophets, may the blessing of God be upon them. But it is not the way that mathematicians have faith in specialists in the demonstrative sciences.[110]

Alhazen described his theology:

I constantly sought knowledge and truth, and it became my belief that for gaining access to the effulgence and closeness to God, there is no better way than that of searching for truth and knowledge.[111]

List of works[edit]

According to medieval biographers, Alhazen wrote more than 200 works on a wide range of subjects, 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 subjects.[112] Not all his surviving works have yet been studied, but some of the ones that have are given below.[93][108]

  1. Book of Optics
  2. Analysis and Synthesis
  3. Balance of Wisdom
  4. Corrections to the Almagest
  5. Discourse on Place
  6. Exact Determination of the Pole
  7. Exact Determination of the Meridian
  8. Finding the Direction of Qibla by Calculation
  9. Horizontal Sundials
  10. Hour Lines
  11. Doubts Concerning Ptolemy
  12. Maqala fi'l-Qarastun
  13. On Completion of the Conics
  14. On Seeing the Stars
  15. On Squaring the Circle
  16. On the Burning Sphere
  17. On the Configuration of the World
  18. On the Form of Eclipse
  19. On the Light of Stars
  20. On the Light of the Moon
  21. On the Milky Way
  22. On the Nature of Shadows
  23. On the Rainbow and Halo
  24. Opuscula
  25. Resolution of Doubts Concerning the Almagest
  26. Resolution of Doubts Concerning the Winding Motion
  27. The Correction of the Operations in Astronomy
  28. The Different Heights of the Planets
  29. The Direction of Mecca
  30. The Model of the Motions of Each of the Seven Planets
  31. The Model of the Universe
  32. The Motion of the Moon
  33. The Ratios of Hourly Arcs to their Heights
  34. The Winding Motion
  35. Treatise on Light
  36. Treatise on Place
  37. Treatise on the Influence of Melodies on the Souls of Animals[113]

Notes[edit]

  1. ^ Now deprecated (Lindberg 1967).

References[edit]

  1. ^ a b c d e (Lorch 2008)
  2. ^ Charles M. Falco (November 27–29, 2007), Ibn al-Haytham and the Origins of Computerized Image Analysis, International Conference on Computer Engineering & Systems (ICCES), retrieved 2010-01-30 
  3. ^ Franz Rosenthal (1960–1961), "Al-Mubashshir ibn Fâtik. Prolegomena to an Abortive Edition", Oriens (Brill Publishers) 13: 132–158 [136–7], JSTOR 1580309 
  4. ^ O'Connor, John J.; Robertson, Edmund F., "Abu Ali al-Hasan ibn al-Haytham", MacTutor History of Mathematics archive, University of St Andrews .
  5. ^ Charles H Carman, John Hendrix, ed. (2012). "2: Classical optics and the perspectivae traditions leading to the Renaissance". Renaissance Theories of Vision. Ashgate Publishing, Ltd. p. 11. ISBN 9781409486510. "Ibn al-Haytham's groundbreaking studies in optics, including his research in catoptrics and dioptrics (respectively the sciences investigating the principles and instruments pertaining to the reflection and refraction of light), were principally gathered in his monumental opus: Kitåb al-manåóir (The Optics; De Aspectibus or Perspectivae; composed between 1028 CE and 1038 CE)." 
  6. ^ Anne Rooney (2012). "Ibn Al-Haytham". The History of Physics. The Rosen Publishing Group. p. 39. ISBN 9781448873715. "As a rigorous experimental physicist, he is sometimes credited with inventing the scientific method." 
  7. ^ David B. Baker, ed. (2012). The Oxford Handbook of the History of Psychology: Global Perspectives. Oxford University Press. p. 449. ISBN 9780195366556. "As shown earlier, Ibn al-Haytham was among the first scholars to experiment with animal psychology." 
  8. ^ Science, Medicine and Technology, Ahmad Dallal, The Oxford History of Islam, ed. John L. Esposito, (Oxford University Press, 1999), 192;"Ibn al-Haytham (d. 1039), known in the West as Alhazan, was a leading Arab mathematician, astronomer, and physicist. His optical compendium, Kitab al-Manazir, is the greatest medieval work on optics".
  9. ^ Helaine Selin, ed. (2008). "M". Encyclopaedia of the History of Science, Technology, and Medicine in Non-Western Cultures, Volume 1. Springer. p. 1667. ISBN 9781402045592. "The three most recognizable Islamic contributors to meteorology were: the Alexandrian mathematician/ astronomer Ibn al-Haytham (Alhazen 965-1039), the Arab-speaking Persian physician Ibn Sina (Avicenna 980-1037), and the Spanish Moorish physician/jurist Ibn Rushd (Averroes; 1126-1198)." 
  10. ^ André Authier (2013). "3: The Dual Nature of Light". Early Days of X-ray Crystallography. Oxford University Press. p. 23. ISBN 9780191635014. "Tables of angles of incidence and refraction were given by the famous Arab mathematician and physicist Alhazen, considered as the 'father of modern optics' and ophthalmology." 
  11. ^ "Abhandlung über das Licht", J. Baarmann (ed. 1882), Zeitschrift der Deutschen Morgenländischen Gesellschaft, Vol. 36.
  12. ^ Thiele, Rüdiger (2005), "In Memoriam: Matthias Schramm", Arabic Sciences and Philosophy (Cambridge University Press) 15: 329–331, doi:10.1017/S0957423905000214 
  13. ^ Thiele, Rüdiger (August 2005), "In Memoriam: Matthias Schramm, 1928–2005", Historia Mathematica 32 (3): 271–274, doi:10.1016/j.hm.2005.05.002 
  14. ^ a b Jim Al-Khalili (4 January 2009). "The 'first true scientist'". BBC News. 
  15. ^ a b (Corbin 1993, p. 149)
  16. ^ (Lindberg 1967, p. 331)
  17. ^ a b c d e f g (O'Connor & Robertson 1999)
  18. ^ a b c d (Sabra 2003)
  19. ^ (Grant 2008)
  20. ^ [1]
  21. ^ Ibn al-Haytham, J. Vernet, The Encyclopaedia of Islam, Vol. III, ed. B. Lewis, V.L. Menage, C. Pellat, J. Schacht (Brill, 1996), 788;" "IBN AL-HAYXHAM, B. AL-HAYTHAM AL-BASRI, AL-MisRl, was identified towards the end of the 19th century with the ALHAZEN, AVENNATHAN and AVENETAN of mediaeval Latin texts. He is one of the principal Arab mathematicians and, without any doubt, the best physicist."
  22. ^ David J. Hess, Science and Technology in a Multicultural World: The Cultural Politics of Facts and Artifacts, (Columbia University Press, 1995), page 66;"It is known that Galileo had a copy of "Opticae Thesaurus" of Ibn al-Haytham (Alhazen), an Arab scientist who was known for his experimental method (Omar 1979:68)."
  23. ^ a b (Whitaker 2004)
  24. ^ (Rashed 2002b)
  25. ^ "the Great Islamic Encyclopedia". Cgie.org.ir. Retrieved 2012-05-27. 
  26. ^ Mohamed, Mohaini (2000). Great Muslim Mathematicians. Penerbit Universiti Teknologi Malaysia. p. 48. 
  27. ^ Sajjadi, Sadegh, "Alhazen", Great Islamic Encyclopedia, Volume 1, Article No. 1917;
  28. ^ (Sabra 2007)
  29. ^ (Sabra 2007, pp. 122, 128–129)
  30. ^ Grant 1974 Alhazen at Google Books notes the Book of Optics has also been denoted as Opticae Thesaurus Alhazen Arabis, as De Aspectibus, and also as Perspectiva
  31. ^ (Lindberg 1996, p. 11), passim
  32. ^ André Authier (2013). "3: The Dual Nature of Light". Early Days of X-ray Crystallography. Oxford University Press. p. 23. ISBN 9780191635021. "Alhazen's works in turn inspired many scientists of the Middle Ages, such as the English bishop, Robert Grosseteste (ca 1175–1253), and the English Franciscan, Roger Bacon (ca 1214–1294), Erazmus Ciolek Witelo, or Witelon (ca 1230* 1280), a Silesian-born Polish friar, philosopher and scholar, published in ca 1270 a treatise on optics, Perspectiva, largely based on Alhazen's works." 
  33. ^ Ahmed H. Zewail; John Meurig Thomas (2010). 4D Electron Microscopy: Imaging in Space and Time. World Scientific. p. 5. ISBN 9781848163904. "The Latin translation of Alhazen's work influenced scientists and philosophers such as (Roger) Bacon and da Vinci, and formed the foundation for the work by mathematicians like Kepler, Descartes and Huygens..." 
  34. ^ Frank Northen Magill; Alison Aves (1998). "The Middles Ages: Alhazen". Dictionary of World Biography, Volume 2. Routledge. p. 66. ISBN 9781579580414. "Sabra discusses in detail the impact of Alhazen's ideas on the optical discoveries of such men as Descartes and Christian Huygens." 
  35. ^ Frank Northen Magill; Alison Aves (1998). "The Middles Ages: Alhazen". Dictionary of World Biography, Volume 2. Routledge. p. 66. ISBN 9781579580414. "Even Kepler, however, used some of Alhazen's ideas, for example, the one-to-one correspondence between points on the object and points in the eye. It would not be going too far to say that Alhazen's optical theories defined the scope and goals of the field from his day to ours." 
  36. ^ a b c d (Dr. Al Deek 2004)
  37. ^ (Topdemir 2007a, p. 77)
  38. ^ a b (El-Bizri 2005a)
    (El-Bizri 2005b)
  39. ^ Chong SM, Lim ACH, Ang PS (2002). Photographic Atlas of the Moon. Appendix 3, pp.129. Alhazen at Google Books
  40. ^ 59239 Alhazen (1999 CR2), NASA, 2006-03-22, retrieved 2008-09-20 
  41. ^ AKU Research Publications 1995-98[dead link]
  42. ^ a b (Murphy 2003)
  43. ^ (Burns 1999)
  44. ^ (Crombie 1971, p. 147, n. 2)
  45. ^ Alhazen (965–1040): Library of Congress Citations, Malaspina Great Books, retrieved 2008-01-23 
  46. ^ (Smith 2001, p. xxi)
  47. ^ a b (Lindberg 1976, p. 73)
  48. ^ (Lindberg 1976, p. 74)
  49. ^ (Lindberg 1976, p. 76)
  50. ^ (Lindberg 1976, p. 75)
  51. ^ (Lindberg 1976, pp. 76–78)
  52. ^ a b (Lindberg 1976, p. 86)
  53. ^ (Heeffer 2003)
  54. ^ (Kelley, Milone & Aveni 2005, p. 83):

    "The first clear description of the device appears in the Book of Optics of Alhazen."

  55. ^ (Wade & Finger 2001):

    "The principles of the camera obscura first began to be correctly analysed in the eleventh century, when they were outlined by Ibn al-Haytham."

  56. ^ (Howard 1996)
  57. ^ a b (Aaen-Stockdale 2008)
  58. ^ (Wade 1998, pp. 240,316,334,367)
  59. ^ (Howard & Wade 1996, pp. 1195,1197,1200)
  60. ^ (Lejeune 1958)
  61. ^ (Raynaud 2003)
  62. ^ Gul A. Russell, "Emergence of Physiological Optics", p. 691, in (Morelon & Rashed 1996)
  63. ^ Gul A. Russell, "Emergence of Physiological Optics", p. 689, in (Morelon & Rashed 1996)
  64. ^ (Lindberg 1976, pp. 80–85)
  65. ^ (Smith 2004, pp. 186, 192)
  66. ^ (Wade 1998, p. 14)
  67. ^ (Toomer 1964, pp. 463–4)
  68. ^ (Toomer 1964, p. 465)
  69. ^ (Weisstein)
  70. ^ (Katz 1995, pp. 165–9 & 173–4)
  71. ^ (Smith 1992)
  72. ^ (Highfield 1997)
  73. ^ (Agrawal, Taguchi & Ramalingam 2011)
  74. ^ a b (Agrawal, Taguchi & Ramalingam 2010)
  75. ^ a b Gul A. Russell, "Emergence of Physiological Optics", p. 695, in Morelon, Régis; Rashed, Roshdi (1996), Encyclopedia of the History of Arabic Science 2, Routledge, ISBN 0-415-12410-7 
  76. ^ a b (Khaleefa 1999)
  77. ^ Ross, H.E. and Plug, C. (2002) The mystery of the moon illusion: Exploring size perception. Oxford: Oxford University Press.
  78. ^ (Hershenson 1989, pp. 9–10)
  79. ^ Ross, H.E. (2000). "Cleomedes (c. 1st century AD) on the celestial illusion, atmospheric enlargement and size-distance invariance". Perception 29: 853–861. 
  80. ^ Ross, H.E.; Ross, G.M. (1976). "Did Ptolemy understand the moon illusion?". Perception 5: 377–385. 
  81. ^ a b (El-Bizri 2006)
  82. ^ (Duhem 1969, p. 28)
  83. ^ a b c (El-Bizri 2007)
  84. ^ (Langerman 1990), chap. 2, sect. 22, p. 61
  85. ^ (Langerman 1990, pp. 34–41)
  86. ^ (Gondhalekar 2001, p. 21)
  87. ^ a b (Sabra 1998)
  88. ^ (Langerman 1990, pp. 8–10)
  89. ^ (Sabra 1978b, p. 121, n. 13)
  90. ^ Nicolaus Copernicus, Stanford Encyclopedia of Philosophy, 2005-04-18, retrieved 2008-01-23 
  91. ^ (Rashed 2007)
  92. ^ (Mohamed 2000, pp. 49–50)
  93. ^ a b (Rashed 2007, pp. 8–9)
  94. ^ a b (Faruqi 2006, pp. 395–6):

    In seventeenth century Europe the problems formulated by Ibn al-Haytham (965–1041) became known as 'Alhazen's problem'. [...] Al-Haytham’s contributions to geometry and number theory went well beyond the Archimedean tradition. Al-Haytham also worked on analytical geometry and the beginnings of the link between algebra and geometry. Subsequently, this work led in pure mathematics to the harmonious fusion of algebra and geometry that was epitomised by Descartes in geometric analysis and by Newton in the calculus. Al-Haytham was a scientist who made major contributions to the fields of mathematics, physics and astronomy during the latter half of the tenth century.

  95. ^ (Rottman 2000), Chapter 1
  96. ^ (Eder 2000)
  97. ^ (Katz 1998, p. 269):

    In effect, this method characterised parallel lines as lines always equidistant from one another and also introduced the concept of motion into geometry.

  98. ^ (Rozenfeld 1988, p. 65)
  99. ^ (Rozenfeld & Youschkevitch 1996, p. 470):

    Three scientists, Ibn al-Haytham, Khayyam and al-Tusi, had made the most considerable contribution to this branch of geometry whose importance came to be completely recognized only in the nineteenth century. In essence their propositions concerning the properties of quadrangles which they considered assuming that some of the angles of these figures were acute of obtuse, embodied the first few theorems of the hyperbolic and the elliptic geometries. Their other proposals showed that various geometric statements were equivalent to the Euclidean postulate V. It is extremely important that these scholars established the mutual connection between this postulate and the sum of the angles of a triangle and a quadrangle. By their works on the theory of parallel lines Arab mathematicians directly influenced the relevant investigations of their European counterparts. The first European attempt to prove the postulate on parallel lines – made by Witelo, the Polish scientists of the thirteenth century, while revising Alhazen's Book of Optics (Kitab al-Manazir) – was undoubtedly prompted by Arabic sources. The proofs put forward in the fourteenth century by the Jewish scholar Gersonides, who lived in southern France, and by the above-mentioned Alfonso from Spain directly border on Ibn Alhazen's demonstration.

  100. ^ Alsina, Claudi; Nelsen, Roger B. (2010), "9.1 Squarable lunes", Charming Proofs: A Journey into Elegant Mathematics, Dolciani mathematical expositions 42, Mathematical Association of America, pp. 137–144, ISBN 978-0-88385-348-1 
  101. ^ (Plott 2000), Pt. II, p. 459
  102. ^ (Smith 2005, pp. 219–40)
  103. ^ (Sardar 1998)
  104. ^ a b (Bettany 1995, p. 251)
  105. ^ (Hodgson 2006, p. 53)
  106. ^ (Sabra 1978a, p. 54)[need quotation to verify]
  107. ^ (Plott 2000), Pt. II, p. 464
  108. ^ a b (Topdemir 2007b)
  109. ^ S. Pines (1962), Actes X Congrès internationale d'histoire des sciences, Vol I, Ithaca, as referenced in Sambursky, Shmuel (ed.) (1974), Physical Thought from the Presocratics to the Quantum Physicists, Pica Press, p. 139, ISBN 0-87663-712-8 
  110. ^ (Rashed 2007, p. 11)
  111. ^ (Plott 2000), Pt. II, p. 465
  112. ^ (Rashed 2002a, p. 773)
  113. ^ (Plott 2000, p. 461)

Sources[edit]

  • Arjomand, Kamran (1997), "The emergence of scientific modernity in Iran: controversies surrounding astrology and modern astronomy in the mid-nineteenth century", Iranian Studies 30 (1) 
  • El-Bizri, Nader (2007), "In Defence of the Sovereignty of Philosophy: Al-Baghdadi's Critique of Ibn al-Haytham's Geometrisation of Place", Arabic Sciences and Philosophy (Cambridge University Press) 17: 57–80, doi:10.1017/S0957423907000367 
  • Faruqi, Yasmeen M. (2006), "Contributions of Islamic scholars to the scientific enterprise", International Education Journal 7 (4): 391–396 
  • Grant, Edward (1974), A source book in medieval science, Volume One, Cambridge MA: Harvard University Press 
  • Hodgson, Peter Edward (2006), Theology And Modern Physics, Burlington, VT: Ashgate Publishing (published 2006-01-15), ISBN 978-0-7546-3622-9, OCLC 56876894, DDC: 201.653, LCC: BL265.P4 H63 2005 
  • Howard, Ian P. (1996), "Alhazen's neglected discoveries of visual phenomena", Perception 25 (10): 1203–1217, doi:10.1068/p251203, PMID 9027923 
  • Howard, Ian P.; Wade, Nicholas J. (1996), "Ptolemy's contributions to the geometry of binocular vision", Perception 25 (10): 1189–201, doi:10.1068/p251189, PMID 9027922 
  • Katz, Victor J. (1995), "Ideas of Calculus in Islam and India", Mathematics Magazine 68 (3): 163–174, doi:10.2307/2691411 
  • Khaleefa, Omar (1999), "Who Is the Founder of Psychophysics and Experimental Psychology?", American Journal of Islamic Social Sciences 16 (2) 
  • Langerman, Y. Tzvi (1990), Ibn al Haytham's On the Configuration of the World 
  • Lejeune, Albert (1958), "Les recherches de Ptolémée sur la vision binoculaire", Janus 47: 79–86 
  • Lindberg, David C. (1967), "Alhazen's Theory of Vision and Its Reception in the West", Isis 58 (3): 321–341, doi:10.1086/350266, PMID 4867472 
  • Lindberg, David C. (1996), Roger Bacon and the Origins of Perspectiva in the Middle Ages, Clarendon Press 
  • Rashed, Roshdi (2007), "The Celestial Kinematics of Ibn al-Haytham", Arabic Sciences and Philosophy (Cambridge University Press) 17: 7–55, doi:10.1017/S0957423907000355 
  • Raynaud, D. (2003), "Ibn al-Haytham sur la vision binoculaire: un précurseur de l'optique physiologique", Arabic Sciences and Philosophy (Cambridge University Press) 13 (1): 79–99, doi:10.1017/S0957423903003047 
  • Rozenfeld, Boris Abramovich; Youschkevitch, Adolf P. (1996), "Geometry", in Rashed, Roshdi, Encyclopedia of the History of Arabic Science 2, London & New York: Routledge, pp. 447–494 
  • Sabra, A. I. (1978b), "An Eleventh-Century Refutation of Ptolemy's Planetary Theory", in Hilfstein, Erna; Czartoryski, Paweł; Grande, Frank D., Science and History: Studies in Honor of Edward Rosen, Studia Copernicana XVI, Ossolineum, Wrocław, pp. 117–131 
  • Sabra, A. I. (2007), "The "Commentary" That Saved the Text. The Hazardous Journey of Ibn al-Haytham's Arabic "Optics"", Early Science and Medicine 12 (2): 117–133, JSTOR 20617660 
  • Samuelson, James; Crookes, William, The Journal of Science, and Annals of Astronomy, Biology, Geology 
  • Smith, A. Mark (2005), "The Alhacenian Account Of Spatial Perception And Its Epistemological Implications", Arabic Sciences and Philosophy (Cambridge University Press) 15, doi:10.1017/S0957423905000184 
  • Topdemir, Huseyin Gazi (July 18, 2007), Ibn al-Haytham (965-1039) His Life and Works 
  • Wade, Nicholas J. (1998), A Natural History of Vision, Cambridge, MA: MIT Press 
  • Wade, Nicholas J.; Finger, Stanley (2001), "The eye as an optical instrument: from camera obscura to Helmholtz's perspective", Perception 30 (10): 1157–1177, doi:10.1068/p3210, PMID 11721819 

Further reading[edit]

Primary[edit]

  • Sabra, A. I., ed. (1983), The Optics of Ibn al-Haytham, Books I-II-III: On Direct Vision. The Arabic text, edited and with Introduction, Arabic-Latin Glossaries and Concordance Tables, Kuwait: National Council for Culture, Arts and Letters 
  • Sabra, A. I., ed. (2002), The Optics of Ibn al-Haytham. Edition of the Arabic Text of Books IV-V: On Reflection and Images Seen by Reflection. 2 vols, Kuwait: The National Council for Culture, Arts and Letters 
  • Smith, A. Mark, ed. and trans. (2001), "Alhacen's Theory of Visual Perception: A Critical Edition, with English Translation and Commentary, of the First Three Books of Alhacen's De aspectibus, the Medieval Latin Version of Ibn al-Haytham's Kitāb al-Manāzir, 2 vols.", written at Philadelphia, Transactions of the American Philosophical Society (Philadelphia: American Philosophical Society) 91 (4-5), ISBN 0-87169-914-1, OCLC 47168716 
  • Smith, A. Mark, ed. and trans. (2006), "Alhacen on the Principles of Reflection: A Critical Edition, with English Translation and Commentary, of Books 4 and 5 of Alhacen's De Aspectibus, the Medieval Latin version of Ibn-al-Haytham's Kitāb al-Manāzir, 2 vols", Transactions of the American Philosophical Society (Philadelphia: American Philosophical Soc.) 96 (2–3), ISBN 0-87169-962-1, OCLC 123464885 185359947 185359957 219328717 219328739 70078653 

Secondary[edit]

  • Graham, Mark. How Islam Created the Modern World. Amana Publications, 2006.
  • Omar, Saleh Beshara (June 1975), Ibn al-Haytham and Greek optics: a comparative study in scientific methodology, PhD Dissertation, University of Chicago, Department of Near Eastern Languages and Civilizations 
  • Belting, Hans, Afterthoughts on Alhazen’s Visual Theory and Its Presence in the Pictorial Theory of Western Perspective, in: Variantology 4. On Deep Time Relations of Arts, Sciences and Technologies In the Arabic-Islamic World and Beyond, ed. by Siegfried Zielinski and Eckhard Fürlus in cooperation with Daniel Irrgang and Franziska Latell (Cologne: Verlag der Buchhandlung Walther König, 2010), pp. 19–42. [2]
  • Siegfried Zielinski & Franziska Latell, How One Sees, in: Variantology 4. On Deep Time Relations of Arts, Sciences and Technologies In the Arabic-Islamic World and Beyond, ed. by Siegfried Zielinski and Eckhard Fürlus in cooperation with Daniel Irrgang and Franziska Latell (Cologne: Verlag der Buchhandlung Walther König, 2010), pp. 19–42. [3]

External links[edit]